In a multi-stage, multi-residue interpolating analog-to-digital converter (ADC), which is suitable for pipelined implementation, inputs of at least three amplifiers are "leapfrog" switched to adjacent nodes of a first interpolation ladder having discrete voltage levels established thereon. Pairs of the amplifiers drive second interpolation ladders to establish additional discrete voltage levels (in a nominal and an overlap conversion region) at nodes of the second interpolation ladders. A bank of comparators compares a predetermined threshold voltage, e.g., ground, to several of the discrete voltage levels at the nodes of the first interpolation ladder. The switches controlling which inputs of the amplifiers are connected to which nodes of the first interpolation ladder are controlled by a logic circuit which is driven by outputs of the bank of comparators. Alternatively, the bank of comparators compares an input voltage of the ADC to voltage levels established by the first interpolation ladder. In which case, the voltages at the nodes of the interpolation ladder to which the amplifiers are connected are amplified with respect to the input voltage of the ADC.

In the electronic field, there is a well recognized need for high-speed, moderate-resolution (i.e., accurate to at least 10 bits) ADCs. There are several known architectures that are suitable for many applications requiring analog-to-digital conversion. Typically, the particular application of a data converter will dictate the architecture that is chosen. Further fine tuning of the chosen architecture will also take place based on the selection of the technology to be used in implementing the converter. It is clear that there is no one optimal architecture for all applications, as all of the known architectures have specific performance advantages and disadvantages, which must be weighed and traded off based on the desired performance goals.
In a low-voltage, e.g., three volt, application, certain implementation problems may arise. For example, it is difficult to implement a high-performance (i.e., high-gain and high-bandwidth) amplifier from a low-voltage supply. Therefore, an ideal ADC architecture would require no amplifiers. To achieve a moderate-resolution conversion with the desired accuracy, however, some amplification is preferred, especially when comparing numerous discrete voltage levels located between reference voltages that are separated by a small voltage difference.
There are two performance specifications that are particularly useful in discussing the relative merit of competing ADC architectures. These include: (1) differential non-linearity (DNL), which is defined as the deviation of the actual code width from the ideal code width; DNL is measured in least significant bits (LSBs), and (2) integral non-linearity (INL), which is defined as the deviation of the converter transfer function from an ideal straight line transfer function; INL also is measured in LSBs and typically is measured with respect to the "best fit" straight line so as not to capture overall converter gain-errors, which are not considered non-linearities.
FIG. 1 is a partial schematic/partial block diagram of a one-step "flash" ADC. As shown, resistor ladder 30, which is connected between voltage node 51 (which receives a high reference voltage V.sub.REFT) and voltage node 53 (which receives a low reference voltage V.sub.REFB), provides discrete voltage levels between each of the resistors in the ladder. Each of these discrete voltage levels is provided to the input of a corresponding comparator in comparator bank 29. Input node 84 is connected to the non-inverting input of each of the comparators. Thus, assuming that the voltage V.sub.REFB at voltage node 53 is lower than the voltage V.sub.REFT at voltage node 51, as the input voltage V.sub.IN increases or decreases gradually, each of the comparators will change states (one at a time). The output of comparators in such an arrangement commonly is referred to as a "thermometer code." Encoder 32 receives the "thermometer code" from the outputs of the comparators and provides, for example, an n-bit binary output code.
Due to the fully parallel architecture of such a flash ADC, the converter is able to perform at extremely high conversion rates. To achieve a conversion having an n-bit resolution using a flash converter, however, 2.sup.n -1 comparators are required. This large number of comparators, in turn, results in a significant consumption of power as well as available die area. The power and area consumed by this architecture grows exponentially with each one-bit increase in the resolution of the converter. In addition, the large number of comparators creates a very large input capacitance seen by input node 84. Therefore, a high performance buffer/amplifier generally is required at the input. For these reasons, flash ADCs typically are restricted to applications requiring a resolution of less than 10-bits.
Implementation of a one-stage "flash" architecture becomes especially difficult if the supply voltage is less than five volts. This difficulty arises because, as the voltage between voltage node 51 and voltage node 53 becomes lower, the voltage difference between the discrete voltage levels created by resistor ladder 30 becomes smaller. That is, because any of the comparators in comparator bank 29 may have an input-referred offset associated therewith, the likelihood that bit-errors (caused by any of such offsets) will appear in the "thermometer code" at the output of the comparators will increase significantly as the difference between the discrete voltage levels is decreased. In other words, if the offset of any comparator is larger than the voltage step between the discrete voltage levels, a bit-error (i.e., a missing code) will result in the "thermometer code." Thus, due to the poor matching properties and limited transconductance of MOS transistors, flash architectures are particularly undesirable for use with CMOS technologies. Therefore, high speed flash ADCs typically are designed for bipolar processes (taking advantage of the excellent matching properties and high speeds attainable with bipolar devices).
An alternative architecture used to perform "flash" analog-to-digital conversions is shown in FIG. 2. This circuit is one implementation of an interpolating flash converter. Amplifiers 58 and 60 represent only two of many amplifiers in amplifier bank 80. Each of these amplifiers has its inverting input connected to a separate node of resistor ladder 30. Voltages at nodes 52 and 54 of resistor ladder 30 are separated by one "coarse" voltage level, which level is determined by the voltage division (of the difference between the reference voltage VREFT and VREFB) that is performed by resistor ladder 30. In FIG. 2, the voltage V.sub.REFT is greater than the voltage V.sub.REFB, so the voltage at node 52 always will be greater than the voltage at node 54. Resistor ladder 56, in turn, is connected (at every fourth node of the ladder) to the outputs of the amplifiers in amplifier bank 80. Each quantizer (e.g., a comparator configured to compare its input with a ground potential, i.e., zero volts) of quantizer bank 82 has an input connected to a corresponding node of resistor ladder 56 in order to compare the voltage at its corresponding node to a ground potential. Each quantizer of quantizer bank 82, therefore, will output a logic-high voltage if its input is above zero volts or a logic-low voltage if its input is below zero volts.
If the voltage V.sub.IN at input node 84 is greater than the voltage at node 52, then the outputs of amplifiers 58 and 60 both will be positive and, thus, the voltages at all nodes of resistor ladder 56 that are below node 74 should be greater than zero volts, thereby causing the quantizers of quantizer bank 82 that are connected to the nodes below node 74 to output a logic-high. Similarly, if input voltage V.sub.IN is less than the voltage at node 54, then the outputs of amplifiers 58 and 60 both will be negative and, thus, the voltages at all nodes of resistor ladder 56 that are above node 66 should be less than zero volts, thereby causing the quantizers of quantizer bank 82 that are connected to the nodes above node 66 to output a logic-low. It follows, then, that when the voltage V.sub.IN at input node 84 is between the voltage at node 52 and the voltage at node 54, at some location in resistor ladder 56 (i.e., either at one of nodes 66, 68, 70, 72 and 74, or at a point internal to one of resistors R1-R4) between the output of amplifier 60 and the output of amplifier 58, the voltage will be equal to zero volts (i.e., a "zero crossing" will occur). Therefore, the quantizers of quantizer bank 82 which are quantizing nodes above this "zero crossing" point will output a logic-low, while the quantizers which are quantizing nodes below this point will output a logic-high. For example, if the "zero crossing" point occurred at a midpoint of resistor R2, quantizers Q2, Q3 and Q4, as well as all quantizers above Q4 in FIG. 2, would output a logic-low signal, whereas quantizers Q1 and Q0, as well as all quantizers below Q0 in FIG. 2 would output a logic-high signal. This results in a "thermometer" output code (which is similar to the "thermometer" code that is output by the comparators in comparator bank 29 (shown in FIG. 1)).
FIG. 3 shows a transfer function of the voltages at each of nodes 66, 68, 70, 72 and 74 in the circuit shown in FIG. 2 (represented by curves 66V, 68V, 70V, 72V and 74V, respectively) versus the input voltage V.sub.IN at input node 84. All of the curves in FIG. 3 are plotted assuming that the amplifiers and quantizers are ideal (i.e., the amplifiers and the quantizers have, respectively, no dc-offset or gain-error). The points where each of curves 66V, 68V, 70V, 72V and 74V cross zero-voltage line 86 correspond to the input voltages at which each of quantizers Q0, Q1, Q2, Q3 and Q4, respectively, should switch states.
FIGS. 4 and 5 each illustrate a significant advantage that is achieved by an interpolating flash ADC such as that shown in FIG. 2. Referring to FIGS. 4 and 5, in conjunction with FIG. 2, several curves 62V, 64V, 66V, 68V, 70V, 72V, 74V, 76V and 78V are shown, which curves could correspond, respectively, to the voltage levels at nodes 62, 64, 66, 68, 70, 72, 74, 76 and 78, as plotted against the input voltage V.sub.IN. In FIG. 4, these curves are shown as they might appear if amplifier 58 had a dc-offset voltage of -1 LSB present on its non-inverting input. Otherwise, the curves in FIG. 4 are plotted assuming that amplifiers 58 and 60 have a gain-error of zero. In FIG. 5, curves 62V, 64V, 66V, 68V, 70V, 72V, 74V, 76V and 78V are shown as they might appear if the gain of amplifier 58 was approximately 30% less than the gain of amplifier 60. Otherwise, the curves in FIG. 5 are plotted assuming that amplifiers 58 and 60 have no input-referred dc-offset.
In FIGS. 4 and 5, dashed curve 88 represents the location of the ideal transfer function for the output of amplifier 58 (i.e., without an input-referred dc-offset or a gain-error) and the dots on zero-crossing line 86, e.g., dot 90, correspond to values of the input voltage V.sub.IN at which the quantizers ideally would have switched states if an input-referred dc-offset or a gain-error were not present. Since the quantizers (shown in FIG. 3) are assumed to be ideal (i.e., they will change states when their inputs "cross" zero volts), the intersections of curves 62V, 64V, 66V, 68V, 70V, 72V, 74V, 76V and 78V with the zero output voltage line (i.e., "zero crossing" line 86) may properly be termed "actual zero crossings," whereas the dots, e.g., dot 90, on "zero crossing" line 86 in each of FIGS. 4 and 5 may properly be called "ideal zero crossings." Curve 92 in FIG. 4 represents the DNL of the circuit caused by the (hypothetical) input-referred dc-offset of amplifier 58, and curve 92 in FIG. 5 represents the DNL of the circuit caused by the (hypothetical) gain error of amplifier 58. Further, curve 94 in FIG. 4 represents the INL of the circuit caused by the (hypothetical) input-referred dc-offset of amplifier 58, and curve 94 in FIG. 5 represents the INL of the circuit caused by the (hypothetical) gain error of amplifier 58. These INL values also are represented in LSBs.
Significantly, in FIG. 4 (i.e., an interpolating flash converter having an amplifier with an input-referred dc-offset), although the maximum INL error of the circuit is no different than that of a flash comparator (such as that shown in FIG. 1), the maximum DNL error is improved by a factor of four. In such a flash interpolation circuit, the DNL caused by the input-referred dc-offsets of any of the amplifiers in amplifier bank 80 will be spread among several of the interpolation points between the resistors in resistor ladder 56. Therefore, if resistor ladder 56 had, for example, eight interpolation points between the outputs of amplifiers 58 and 60 (rather than four interpolation points, as shown in FIG. 2), the DNL caused by a one-LSB input-referred dc-offset would be divided effectively by a factor of eight, and the resulting DNL of the ADC would be only one-eighth of an LSB.
In the circuit of FIG. 5 (i.e., an interpolating flash converter having an amplifier with a certain hypothetical gain-error), both the INL and DNL of the ADC caused by a somewhat drastic, i.e., approximately 30%, gain-error between adjacent amplifiers, are acceptable for most applications. But, the non-linearity of an interpolating flash converter that is caused by gain mismatches between adjacent amplifiers is substantially worse than that of standard flash converters (such as that shown in FIG. 1), wherein gain mismatches between adjacent comparators have no effect on the DNL or INL of the flash converter. Therefore, the interpolation architecture essentially trades off a small amount of gain mismatch sensitivity for a reduction in offset sensitivity. In addition, the interpolating flash architecture requires far fewer amplifiers than does the standard flash architecture (which uses amplifiers to compare the input voltage with each and every voltage level), thereby resulting in a significant reduction in the required die area and the power consumption of the interpolating flash ADC.
Another way to obtain high-speed, moderate-resolution, analog-to-digital conversion using CMOS flash convertors (such as that shown in FIG. 1) is to employ a multi-stage pipeline architecture such as that shown in FIG. 6. By using a multi-stage architecture, the total number of comparators required to perform a conversion is reduced significantly. In fact, for a n-bit conversion, the required number of comparators is reduced from approximately 2.sup.n (as are required for a full flash convertor) to approximately 2.sup.n/2+1. This reduction in the number of required comparators results in a significant die area and power consumption savings for the ADC. The two-stage pipeline converter shown in FIG. 6 is a specific example of a general class of convertors known as multi-step convertors.
The operation of the two step converter shown in FIG. 6 is fairly straightforward. First, a "coarse" conversion of the voltage V.sub.IN at input node 84 is made by n-bit ADC 34, which coarse conversion is an n-bit approximation of the input voltage V.sub.IN. N-bit digital-to-analog convertor (DAC) 36 converts the n-bit digital approximation (performed previously by n-bit ADC 34) back into an analog signal. This analog signal (representing the "coarse" n-bit approximation of the input voltage V.sub.IN) is subtracted from the input voltage V.sub.IN at subtraction node 44. The result of this subtraction is termed the "residue" of the first n-bit conversion, as it represents the residual portion of the input voltage V.sub.IN that was not accurately converted by the n-bit ADC 34. This residue then is amplified by amplifier 38 so as to enlarge the conversion range for a second or "fine" conversion, which fine conversion is performed by m-bit ADC 40. The "fine" m-bit digital word output by m-bit ADC 40 then is passed to adder 42 where it is added to the "coarse" n-bit conversion previously performed by n-bit ADC 34.
Often, as is shown in FIG. 6, the gain of the inter-stage amplifier is set such that the coarse and fine conversions have a one-bit overlap so as to allow for the correction of errors made in the coarse conversion (as discussed further below). When such an overlap is employed, the output of adder 42 provides an (m+n-1)-bit digital word. The two-stage architecture shown in FIG. 6 may be extended further to an arbitrary number of stages, with the residue of each stage being amplified and quantized by the following stage. The limiting example of such an extension is a one-bit-per-stage architecture, which requires only one comparator per added bit of resolution desired.
FIG. 7 illustrates how a gain-error in amplifier 38 can cause significant errors to appear at the output of the pipeline convertor shown in FIG. 6. Upper curves 46 and 48 show the output voltage of amplifier 38 (i.e., the amplified residue) plotted against the input voltage V.sub.IN of n-bit ADC 34. Lower curves 50 and 52 in FIG. 7 show the analog representation of the digital output code (CODE) of adder 42 plotted against the input voltage V.sub.IN of n-bit ADC 34, which is the same voltage V.sub.IN that forms the horizontal axis for upper curves 46 and 48. The transfer function of curve 46 (which represents a situation when the gain of amplifier 38 is ideal, i.e., is exactly equal to 2.sup.n-1), results in a nearly liner correspondence between the input voltage V.sub.IN and the digital output code (CODE) (as shown by curve 50). The transfer function of curve 48 (which represents the output voltage of amplifier 38 when its gain is non-ideal, i.e., is less than 2.sup.n-1), results in a digital output code (as shown by curve 52) with numerous non-linearities and possible missing codes.
There are a number of significant characteristics of multi-step convertors that may be noted. In general, the quantizers of each stage need only be accurate (i.e., linear) to the number of bits converted in that particular stage. The DACs and subtraction circuitry, however, must have an accuracy that is commensurate with the remaining accuracy of the convertor. Also, the gain of the inter-stage amplifier, such as amplifier 38 in FIG. 6, must be highly accurate so as to assure the proper quantization in the following stages. This stringent constraint on the accuracy of the inter-stage gain usually dictates that a high-gain amplifier (in a feedback configuration) be employed. The presence of a closed-loop amplifier in the signal path, however, typically limits the overall conversion rate of the pipelined converter.
The addition of sample and hold amplifiers between stages of a multi-step architecture allows adjacent stages to be pipelined, thereby increasing the throughput rate of the convertor. Thus, if the desired accuracy of the DACs, the subtractors, and the inter-stage amplifiers can be attained, such a multi-stage pipelined convertor provides an architecture that can feasibly be implemented using CMOS technology. As mentioned previously, however, the speed limitation of the high-gain amplifier in a feedback configuration normally will limit the overall speed of a multi-stage pipelined convertor.
Multi-stage architectures have the further benefit of reducing the required accuracy of the comparators in the first stage and in each subsequent stage of the convertor. That is, since fewer reference levels are required in the first stage (resulting in a larger voltage difference between adjacent reference levels), and since the residue from each preceding stage is amplified by an amount proportional to the gain of the inter-stage amplifier, the accuracy requirement of the comparators in all of the stages is significantly reduced. By taking advantage of this reduced accuracy requirement, power and die area savings may be realized by employing less accurate comparators, which consume less power and have a smaller size.
Digital error correction is used almost universally in multi-step architectures. Such a correction technique reduces the accuracy requirement of the quantizers in each stage by converting the residue passed to succeeding stages into digital words having an extra bit of accuracy. This extra bit of accuracy in the succeeding stages commonly is referred to as the "overlap" range of the succeeding stage. This extra range should be sufficient to correct any errors made by the preceding quantizer.
FIG. 8 illustrates the coding of two successive stages of a convertor wherein no overlap range is provided and, thus, no digital error correction can be performed. In this case, the ADC, DAC, and subtractor of stage i are ideal, so one voltage step of stage i is amplified to fill the full-scale range of stage i+1. In contrast, FIG. 9 illustrates the coding of the same two stages that are illustrated in FIG. 8, but with a (hypothetical) dc-offset added to two of the voltage levels in stage i. Because of these dc-offsets, the amplified signal range now falls outside of the full-scale input range of stage i+1 (i.e., a wide code or positive DNL results). As shown, this mismatch results in a region of overflow above the top voltage level of stage i+1 and a region of missing codes at the lowest voltage level of stage i+1.
FIG. 10 illustrates how an "over" and "under" overlap range may be used to compensate for quantizer offset errors in a multi-stage pipelined ADC, such as that shown in FIG. 6. As shown in FIG. 10, by reducing the inter-stage gain to .+-.one-half of the value of the inter-stage gain used in FIG. 9, the signal range of the amplified residue from stage i now falls only in the middle portion of the conversion region of stage i+1. Due to this reduction in the inter-stage gain, the convertor shown in FIG. 6 now can tolerate dc-offset errors of up to one-half of an LSB in the quantizer stage i. For signals that fall in the "over" range of stage i+1, an overlap add is performed to increment stage i's quantization output by one LSB. Signals that fall in the "under" range cause the digital correction circuit to subtract one LSB from the quantization output of stage i. Thus, this digital correction technique greatly eases the constraints imposed on the quantizers employed in each stage.
In a multi-stage ADC architecture (such as that shown in FIG. 6), if the reference voltage for m-bit ADC 40 (e.g., the difference between the voltages V.sub.REFT and V.sub.REFB in a flash ADC such as that shown in FIG. 1) was passed through a unity-gain amplifier with a percentage gain-error identical to the percentage gain-error of amplifier 38 (shown in FIG. 6), the reference range of m-bit DAC 40 then would match the full-scale range of the amplified residue from the output of amplifier 38. Unfortunately, creating a matching gain-error in a reference-buffer amplifier is not a feasible approach in CMOS. An alternative, but substantially equivalent approach, is to have the amplified residue carry the reference information for the following stage. This approach has been successfully implemented using architectures known as "multi-residue, interpolating converters."
A schematic of a multi-stage, two-residue, interpolating converter is shown in FIG. 11. The operation of this circuit is similar to that of the interpolating flash converter shown in FIG. 2. The inverting inputs of amplifiers 102 and 104, however, are not permanently connected to nodes 118 and 120 of resistor ladder 96, while the inverting inputs of amplifiers 58 and 60 (in FIG. 2) are permanently connected to nodes 52 and 54, respectively, of resistor ladder 30 (as shown in FIG. 2). Rather, leads 110 and 112 are switched so that they are connected only to: (1) the node (of resistor ladder 96) having a voltage level thereon that is closest to the input voltage V.sub.IN at input node 84, and (2) the node (of resistor ladder 96) having a voltage level thereon that is next closest to the input voltage V.sub.IN. This connection of leads 110 and 112 causes the following results: (1) the voltage at node 118 will be greater than or equal to the input voltage V.sub.IN, and (2) the voltage at node 120 will be less than or equal to the input voltage V.sub.IN. This, in turn, dictates that: (1) the output of amplifier 102 will be negative, and (2) the output of amplifier 104 will be positive.
Arrow 122 represents the input voltage V.sub.IN at input node 84 as it would appear relative to the voltage gradient formed by resistor ladder 96. The locations of the closest and second closest reference voltages (relative to the input voltage V.sub.IN) are determined by using comparators (not shown) to compare the input voltage V.sub.IN with the voltage at each of the nodes of resistor ladder 96. The outputs of these comparators are used as: (1) a digital output representing a first-stage "coarse" quantization of the input voltage V.sub.IN , which may later be added to "finer" measurements from succeeding stages, and (2) a means to control switches which switch leads 110 and 112 of amplifiers 102 and 104, respectively, to the nodes of resistor ladder 96 which are, respectively, greater than (or equal to) and less than (or equal to) the input voltage V.sub.IN at input node 84.
As previously mentioned, the switching of leads 110 and 112 such that they surround the input voltage level dictates that the voltage at the output of amplifier 102 will be negative and the voltage at the output of amplifier 104 will be negative. Therefore, at some point in resistor ladder 98, the voltage will transition from a negative voltage to a positive voltage, i.e., a "zero crossing" will occur. In the example of FIG. 11, arrow 124 represents the relative location of this "zero crossing" along the voltage gradient formed by resistor ladder 98. In an identical manner as with the interpolating flash circuit shown in FIG. 2, quantizers (not shown) are connected to each of the interpolating nodes of resistor ladder 98 in order to determine between which two nodes a "zero crossing" occurs. As with the first stage, the outputs of the quantizers are used: (1) as a second-stage digital output, which represents a digital approximation of the residue from the first stage (i.e., the portion of the signal not accurately represented by the digital value determined by the first stage), and (2) as a means to control switches which connect leads 114 and 116 of amplifiers 106 and 108, respectively, to adjacent nodes of resistor ladder 98 that surround the determined location of the "zero crossing" of resistor ladder 98.
Due to this switching, the voltage at lead 114 should be negative and the voltage at lead 116 should be positive, causing the outputs of amplifiers 106 and 108 to be, respectively, negative and positive as well. This creates a "zero crossing" along the voltage gradient formed by resistor ladder 100, which "zero crossing," in this example, is represented by arrow 126. As with the second stage, resistor ladder 100 has quantizers connected to each of its nodes to determine the location of the "zero crossing" and output a corresponding digital output code.
A multi-stage, two-residue architecture (such as that shown in FIG. 11) has several advantages over basic interpolating flash ADCs (such as that shown in FIG. 2). One such advantage is a significant reduction in the number of amplifiers and comparators that are required for its implementation (as compared to the flash or interpolating flash architectures discussed previously). This reduction in the required number of amplifiers and comparators is due, in part, to the fact that the circuit elements used in the successive stages are switched to be connected to the appropriate inputs (rather than being duplicated in the circuit), and results in a significant reduction of the power consumption and required die area of the circuit.
Another advantage attained by a two-residue structure is illustrated in FIG. 12. FIG. 12 shows transfer functions of the voltages at the outputs of amplifiers 102 and 104, as well as the voltages at several resistor ladder nodes therebetween, versus the input voltage V.sub.IN at input node 84. As shown, curves 128A and 130A represent the outputs of amplifiers 102 and 104, respectively, when both of these amplifiers have a gain equal to A. Similarly, curves 128B and 130B represent the outputs of amplifiers 102 and 104, respectively, when both of these amplifiers have an gain equal to B. The lines between curves 128A and 130A and between curves 128B and 130B represent the voltages at several of the nodes of resistor ladder 98. The parallel dashed lines, e.g., line 132, illustrate how the "zero crossings" of each of the nodes of the resistor ladder occur at the same location regardless of the gain setting of amplifiers 102 and 104, so long as the gain of amplifier 102 substantially matches the gain of amplifier 104.
Interestingly, if both of amplifiers 102 and 104 have linear settling (i.e., no slewing), then complete settling is not required in order to obtain converter linearity. This property is in stark contrast to standard multi-step architectures (such as that shown in FIG. 6), wherein complete settling of the inter-stage amplifier is paramount to the performance of the converter. In fact, the settling time of the interstage amplifier in a multi-step ADC architecture typically is the speed-determining factor of such an ADC. Thus, the fact that the amplifiers in a two-residue architecture do not have to settle completely significantly eases the performance requirements of these amplifiers.
FIG. 13 illustrates a switching scheme for the amplifiers in a two-residue architecture. Resistor ladder 142 in FIG. 13 could, for example, correspond to resistor ladder 98 in FIG. 11, and amplifiers 134 and 136 in FIG. 13 could correspond, respectively, to amplifiers 106 and 108 in FIG. 11. Arrow 138 in FIG. 13 represents the "zero crossing" of resistor ladder 142 and voltage source 140 represents an input-referred dc-offset of amplifier 136. As depicted by phantom amplifiers 134P and 136P, when amplifiers 134 and 136 are switched between nodes of resistor ladder 142, they do so in a "sliding" fashion. That is, the inputs of amplifiers 134 and 136 both are switched to be connected to the next adjacent node in resistor ladder 142.
Referring now to FIG. 14, in conjunction with FIG. 13, the output voltages of amplifiers 134 and 136 are plotted as curves 134V and 136V, respectively, versus the input voltage of the circuit. If it is assumed that the location of the "zero crossing" shown by arrow 138 initially occurs just below the node of the resistor ladder to which the input of amplifier 134 is attached, then as the input voltage is increased slightly, amplifiers 134 and 136 will be switched so that amplifier 136 will be connected to the node to which amplifier 134 was initially attached and amplifier 134 will be connected to the node just above the node to which it initially was attached. This manner of switching causes the offset voltage at the input of amplifier 136 to appear suddenly at the ladder node to which amplifier 134 was previously attached. This voltage step causes the transfer function of the converter to be irregular, as represented by curve 146 in FIG. 14. As shown in FIG. 14, line segment 150 (which could represent an interpolated voltage at a node of resistor ladder 142 between the outputs of amplifiers 134 and 136) does not intersect "zero crossing" line 144. This non-intersection with the "zero crossing" line, in turn, would result in a missing code (i.e., a DNL error of -1 LSB) after every "sliding" switch of amplifiers 134 and 136. The effect of these missing codes on the output code is illustrated by curve 146 in FIG. 14, as compared to curve 148, which represents how the output code curve might appear with no amplifier offset.
FIG. 15 is identical to FIG. 13, except that amplifiers 134 and 136 now are switched using a "leapfrog" method, as is illustrated with phantom amplifier 136P. With the switching scheme shown in FIG. 15, however, if it again is assumed that the "zero crossing" point initially occurs at a location just below the resistor ladder node to which the input of amplifier 134 initially is attached (as indicated by arrow 138), when the input voltage is increased slightly, the quantizers connected to resistor ladder 142 will cause the input of amplifier 136 to switch to the node just above the node to which amplifier 134 is attached. This manner of switching means that the offset voltage will not appear suddenly at a ladder node that is very close to the "zero crossing" point of ladder 142. Rather, the offset voltage will appear at a ladder node that is an entire (coarse) voltage level above the "zero crossing" point. Therefore after a "leapfrog" switch of the amplifiers, the quantization error introduced by any offset voltage will be "spread" between the interpolated voltage levels between the outputs of amplifiers 134 and 136, thereby substantially reducing its deleterious effect on the DNL of the converter.
The output voltages (relative to the input voltage V.sub.IN ) of amplifiers 134 and 136 are shown in FIG. 16 as curves 134V and 136V, respectively. The line segments, e.g., line segment 150, represent the voltages at the nodes of resistor ladder 142 between the outputs of amplifiers 134 and 136. As shown in this example, each of these interpolated line segments intersects "zero crossing" line 144, resulting in a "zero crossing" for each interpolation node. An analog representation of the output code of the converter corresponding to the output voltages shown thereabove is represented by curve 148 in FIG. 16, as compared to ideal code curve 146. As a result of this "leapfrog" switching scheme, while the INL of the converter suffers slightly, since there is no abrupt voltage transition when an amplifier having an offset is switched to a new node (as previously explained in connection with the discussion of FIG. 14), the DNL is significantly improved. That is, there should be no missing codes so long as the input-referred offset of the amplifiers is less than the difference between (coarse) voltage levels of resistor ladder 142.
Still referring to FIG. 15, since amplifiers 134 and 136 are "leapfrog" switched responsive to the detection of a "zero crossing" at each node of resistor ladder 142, any offset in the quantizers (e.g., dc-offset voltages at the inputs of comparators) may cause the amplifiers to be switched too early or too late. That is, instead of detecting a "zero crossing," the quantizers might detect a crossing at a voltage that is slightly less than zero or slightly greater than zero. This early or late switching could result in missing codes if the offset of the quantizers is large enough.
One solution to the problem of early or late switching of the quantizers is to create an "overlap range" which extends beyond the nominal resolution of the interpolating ladder that is connected between the outputs of the two amplifiers. This overlap scheme is illustrated in FIGS. 17(a) and 17(b). FIG. 17(a) shows amplifiers 134 and 136 having only a nominal conversion range between their outputs, whereas FIG. 17(b) shows the amplifiers having an artificially created "over" range above the output of amplifier 134 and an "under" range below the output of amplifier 136. The nodes of the interpolation ladder in these "over" and "under" ranges may be quantized as are the nodes between the outputs of amplifiers 134 and 136. Using this overlap arrangement, if amplifiers 134 and 136 are switched either too early or too late so that a "zero crossing" occurs at, for example, node 152 or node 154 of resistor ladder 156, the location of this zero crossing will be recognized to have occurred in the "over" or "under" range and the code quantized by the previous stage may be corrected digitally. For example, correction may be accomplished by adding or subtracting one bit from the digital output code of the previous stage. This overlap range and addition (or subtraction) of bits is conceptually identical to the overlap range and addition (or subtraction) of bits discussed in connection with the multi-stage flash ADC shown in FIG. 6.
Referring still to FIG. 17(b), for this overlap scheme to function properly, the voltage steps of the "over" and "under" ranges should (substantially) match the voltage steps of the nominal range. Since the "over" and "under" ranges are artificially created (e.g., using current sources 158 and 160), however, it is unlikely that the voltage steps of these ranges will match the voltage steps of the nominal range. Such a mismatch between conversion ranges may cause converter DNL. One solution of this problem of mismatching between the voltage levels of the overlap and nominal ranges is to amplify the residues of three nodes of the first interpolation ladder and perform interpolation between the outputs of all three amplifiers.
An example of this three-residue scheme is shown in FIG. 18. As shown, the residue between the voltage level at each node of resistor ladder 162 and the input voltage V.sub.IN at input node 84 is amplified and provided at the output of each of the amplifiers in amplifier bank 164. Comparators, e.g., comparator 170, have inverting inputs positioned at the midpoints of the resistors in resistor ladder 162 so as to receive a voltage that is offset from the voltages at the nodes of resistor ladder 162 by one-half of a voltage step. A comparison of these voltages at levels (intermediate to the voltage levels of the resistor ladder) will cause switches 172, 174 and 176 to switch block 168 (in a sliding fashion) to three adjacent output nodes of particular amplifiers in amplifier bank 164. Block 168 includes buffers 173, 175 and 177 (which are connected to one pole of switches 172, 174 and 176, respectively) and interpolation ladders 179 and 181 which are connected to the outputs of buffers 173, 175 and 177, as shown.
Using three residues in this manner has at least one significant advantage in that "over" and "under" conversion ranges (in addition to a nominal conversion range) are inherently created by such an architecture. That is, since switches 172, 174 and 176 are connected between the outputs of three adjacent amplifiers (rather than between the outputs of only two amplifiers), extra voltages levels (i.e., voltage levels that are not required for a "nominal" range conversion) are generated by interpolation ladders 179 and 181. The "over" and under ranges of the amplifier may then be employed in a similar manner as the "over" and "under" ranges were employed in the circuit of FIG. 17(b). The voltage levels in one section of an interpolation device (internal to fine comparator block 168) is used to perform the "nominal range" conversion, and other portions of this interpolation device may be used to perform an "under" or "over" range conversion, if required, for example, due to an offset of a comparator, e.g., comparator 170.
The conversion scheme shown in FIG. 18, however, has several drawbacks. One drawback is that amplifier bank 164 requires a large number of amplifiers to achieve the desired resolution. Such a large number of amplifiers will consume a large amount of die area and power. Another drawback is that DNL errors may arise due to the fact that fine comparator block 168 is switched (between the outputs of the amplifiers in amplifier bank 164) in a "sliding" fashion. Any offset or gain differential on, respectively, an input of an amplifier or between a particular pair of amplifiers in amplifier bank 164 may cause a "spreading" and/or "narrowing" of the interpolation steps between the outputs of two of the amplifiers, as is illustrated in FIGS. 4 and 5. Due to this possible difference in the size of the voltage level steps between the outputs of any two adjacent amplifiers, the size of the voltage level steps in the "over" or "under" range (if used) will not necessarily match the size of the voltage level steps in the next "nominal" range after fine comparator block 168 is switched to the next adjacent set of amplifier outputs. Consequently, this mismatch between the size of the voltage level steps of the nominal range and the "over" or "under" range of a three-residue scheme may result in DNL errors.
It therefore is a general object of the invention to provide an improved interpolating ADC that overcomes several of the disadvantages and drawbacks of prior art ADCs.

Multi-stage interpolating analog-to-digital conversion


The invention is a sealing means in a spray nozzle assembly which includes the provision of a groove adapted to at least partially accommodate a sealing means such as an O-ring in the surface of an upper face of an orifice disc said face being directed towards a lower face of an inner periphery of a nozzle cap.

Spray nozzle type devices customarily consist of a nozzle body extending from a fluid inlet end to a fluid outlet end the interior of which body defines a central bore housing, among other possible components, a swirl device and an orifice disc.
It is well known for an outlet face of the orifice disc to abut a landing defined by an inner periphery of the nozzle cap about a central bore and to be provided with a seal between the disc and cap.
In the prior art it has been known to provide a compressive seal at the front of the nozzle, between the inner housing and the orifice disc, using a fiat washer seal.
Such a washer seal does not provide for particularly reliable sealing at elevated pressure and temperature, with the flat seal likely to be squeezed out of the mating surfaces under some conditions.
Other types of sealing means are used in spray nozzle assemblies for example a new system has been developed which uses two independent O ring seals in compression (as opposed to a common axial body seal coupled with a front compressive seal) to form the pressure containing function for the entire nozzle assembly, whereby one O ring resides at the front of the assembly within the nozzle cap, and provides a seal between the orifice disc and the inner nozzle cap housing, and the other seal exists at the rear sealing face of the nozzle cap housing where it engages the face of the housing body via a screwed mechanism, forming the final seal.
This new sealing method allows for much higher pressure ratings than were possible with the prior art.
A further improved sealing method used in the prior art is an O ring seal groove situated inside the inner cap housing within the lower periphery of the nozzle cap, designed to conform to known sealing gland dimension standards, and allowing for correct sealing between the orifice disc and the inner cap housing. This arrangement however reduces the pressure retaining wall thickness between the inner depth of the o-ring groove and the outer surface of the housing, whose outer profile form is restricted by the need to prevent impeding the emitted spray from the orifice disc, thus compromising the mechanical strength of the housing itself.
In this prior art, the nozzle disc typically abuts a single radial mating surface inboard of the O-ring groove in the nozzle cap, with the outer diameter of the orifice disc being free and unsupported at the outer O-ring groove, which is flush with the accommodating diameter of the disc housing bore and larger In diameter than the orifice disc due to normal clearance requirements.
This typical arrangement provides little mechanical support for the compressive forces required to create an adequate face to face seal without gaps. Also, when such required compressive forces are applied, a bending moment is applied to this radial mating surface inboard of the O-ring groove, placing a bending stress upon the thinner area between the outer face of the component housing the seal groove, and the innermost O-ring groove depth, which can result in failure of this innermost radial mating surface, and in worst case scenarios, cause this entire middle section to push outward and fracture away. Thus this arrangement is not conducive to high pressure operation.
A method used to reduce the need for an O-ring groove in the inner cap, was to simply use an O-ring in compression, much like the flat washer, and not provide any sealing grooves for the proper sealing of the parts. In this case a cavity is provided between the disc and the housing cap. This variation has distinct pressure limitations where the sealing cavity formed conforms to no known sealing conventions.


The present invention is an improved computer mouse for inputting cursor commands into a computer of the type having a flat base with a tracking means for use on a flat work surface and switches operable with the fingers of the user. The improved computer mouse comprises a housing having a flat base, a vertical rear wall at a right angle to said flat base, a top and front surface disposed between the front edge of the base and the upper edge of the rear wall. The base having a front to rear dimension less than the height of the rear wall, so that the mouse is readily tiltable rearwardly. Also provided is a means for disabling the mouse when so tilted. The top and front surface being so disposed and elevated such that the user""s hand is positioned above the work surface: (i) so that his/her fingers drape over the mouse touching the work surface or slightly thereabove, and (ii) so that the user""s wrist is straight or substantially straight whereby repetitive or prolonged use of the mouse will lessen the likelihood of developing carpal tunnel syndrome, tendonitis or a related condition.

The present invention relates generally to a computer mouse, and in particular to a computer mouse which eliminates user susceptibility to injuries such as carpal tunnel syndrome, tendonitis, and others.
Computers are usually equipped with a mouse to control the movement of the cursor. In the past, the computer mouse was designed mainly with the functional aspects of the mouse in mind and little effort was placed with regard to the user""s body. As many computer users have suffered injuries such as carpal tunnel syndrome, tendonitis and others caused by the prolonged use of a computer mouse, manufacturers now attempt to design computer equipment including the computer mouse with the safety of the user in mind. However, to this day, most computer mouse developed heretofore do not prevent injuries to a user""s wrist such as those mentioned above.
Many mouse designed for use with a computer are sized such that a user""s wrist rests on a work surface rear of the mouse and the user""s hand extends over the mouse. This position places the wrist in a compressed and vulnerable position, susceptible to wrist injuries such as those identified above. Prolonged compression of the wrist can result in other problems as well which may cause other injuries, such as: pressure on the wrist, tension in the fingers, the elbow and shoulder can become tense and locked which can cause further tension in the neck and head, the torso can fall forward creating additional pressure in the user""s arm.
Numerous attempts have been made to rectify these problems including various mouse designs and other apparatus designed to support the wrist and arm of the computer mouse user. Many mouse designs attempting to eliminate wrist injuries are based on ergonomics and the comfort of the user. Even the ergonomic computer mouse designs that purport stress-free wrists, relieve stress mostly only in the wrist and thumb areas of the body. These designs still allow the arm to drop onto the mouse and do not teach the user to maintain a natural use of the arm. These ergonomically designed computer mouse may have some success in preventing wrist injuries, however user""s may still be susceptible to injuries in other parts of the body such as the neck and back or even the thighs, knees, ankles, and toes.
The computer mouse of the present invention was designed in view of the Alexander Technique, developed by the late Frederick Alexander, which teaches a method of improving one""s posture by developing an awareness of it. Alexander has shown that the body is a unique system and that improved posture can prevent misuse and deterioration of the human body due to extended strains. The present invention computer mouse teaches the user to extend both the wrist and fingers while using the mouse by ceasing to work if the user""s wrist is in a compressed or bent configuration. The present invention mouse successfully eliminates user susceptibility to injuries such as carpal tunnel syndrome, tendonitis and others commonly caused by extended use of a standard computer mouse.
Computer use is still rapidly growing throughout the world and with the onslaught of Internet based information and menu driven web-pages, the computer mouse is a tool used more than ever before by computer users.
Accordingly, there is a need for a computer mouse that is safe for a computer user to operate without the risk of painful and debilitating injuries. The present invention computer mouse prevents user susceptibility to injuries, is simple in design, inexpensive to manufacture and can be used with any cursor tracking method.
The present invention provides an improved computer mouse which reduces user susceptibility to weakness and other hand, wrist and other bodily injuries such as carpal tunnel syndrome, tendonitis and other injuries caused by prolonged or repetitive use of a computer mouse. This device teaches a user to maintain his/her wrist in an extended position by ceasing to function if the user""s wrist collapses into a compressed or bent position in which it becomes susceptible to the wrist and hand injuries identified above. Thus by not functioning if the user""s wrist is in a compressed or bent position, the present invention computer mouse eliminates user susceptibility to the types of injuries identified above from prolonged or repetitive use of a computer mouse.
The present invention is an improved computer mouse for inputting cursor commands into a computer of the type having a flat base with a tracking means for use on a flat work surface and switches operable with the fingers of the user. The improved computer mouse comprises a housing having a flat base, a vertical rear wall at a right angle to said flat base, a top and front surface disposed between the front edge of the base and the upper edge of the rear wall. The base having a front to rear dimension less than the height of the rear wall, so that the mouse is readily tiltable rearwardly. Also provided is a means for disabling the mouse when so tilted.
The computer mouse of the present invention further comprises a top and front surface being so disposed and elevated such that the user""s hand is positioned above the work surface: (i) so that his/her fingers drape over the mouse touching the work surface or slightly thereabove, and (ii) so that the user""s wrist is straight or substantially straight whereby repetitive or prolonged use of the mouse will lessen the likelihood of developing carpal tunnel syndrome, tendonitis or a related condition. The disabling means teaches the user to maintain his/her wrist in this extended position while operating the improved computer mouse of the present invention.
In one embodiment, the improved computer mouse comprises a top and front surface which is convex, alternatively, in another embodiment of the present invention, the top and front surface is angular. In either configuration the top and front surface protrudes outward such that the user""s fingers must be extended to operate the plurality of switches disposed on the lower portion of the top and front surface of the mouse.
The protruding top and front surface of the claimed computer mouse is designed specifically to accommodate only a limited portion of the user""s hand. In the preferred embodiment of the present invention, the top and front surface is dimensioned to accept only two of the metacarpalphalangeal joints and two extended fingers of the user. In another embodiment, the top surface is slightly wider, designed to accept three extended fingers and three metacarpalphalangeal joints of the user""s hand. In either design, the limited size of the protruding top and front surface of the computer mouse prevents the user from resting a major portion of his/her hand on the mouse which teaches the user to support the weight of his/her hand and wrist with his/her arm.
The substantially vertical rear wall of the present invention computer mouse has an overall height dimensioned such that when the mouse is in use, and the user is gripping the mouse, the wrist of the user is in an extended position spaced apart from the work surface and supported entirely by the arm of the user. In this position, the user""s wrist is positioned above the upper edge of the rear wall of the mouse. Collapse of the user""s wrist such that any portion of the user""s wrist falls below the upper edge of the rear wall while the user is gripping the mouse causes the computer mouse to tilt rearwardly such that the base of the mouse is rotated away from the work surface about an axis formed by the intersection of the bottom edge of the rear wall and the rear edge of the base causing the mouse to cease to function.
In combination, the limited size of the protruding top and front surface, the overall height of the substantially vertical rear wall of the housing and the position of the switches along the lower edge of the protruding top and front surface of the computer mouse, teach the user, while using the mouse, to support his/her wrist and hand with the user""s own arm such that the wrist is spaced apart from the work surface and in an extended position.
The fingers resting on the protruding top surface of the mouse must be extended to operate the switches positioned along the lower edge of the protruding top surface of the computer mouse. Also the present invention computer mouse ceases to function if the flat base of the mouse is lifted off of the work surface. The susceptibility of the user to hand and wrist injuries caused by operating a computer mouse with a bent or compressed wrist is thus eliminated in the computer mouse of the present invention.
The switches positioned along the lower edge of the protruding top and front surface of the present invention control the computer in a fashion typical to any computer mouse. The switches can be a plurality of push button, roller, touch key, or any suitable switch. Typically a computer mouse has at least left and right click switches, sometimes either a central roller or third switch is provided. The computer mouse of the present invention can employ any type and configuration of available switches. The mouse of the present invention has a symmetrical design such that it can be used in either the user""s left or right hand and therefore the switches along the lower edge of the protruding top surface can function as either left or right switches.
The preferred embodiment of the computer mouse of the present invention comprises a top and front surface having a minimum height of about two inches so that the user""s wrist is spaced apart from the work surface and wherein the user must support his wrist with his arm, rather than the computer mouse or the work surface. Therefore, the minimum rear wall height of the housing is also about two inches. This arrangement, although seemingly cumbersome, maintains the wrist in a safe position free to move about and also eliminates user susceptibility to the injuries described above. In embodiments designed for children or persons with small hands the present invention computer mouse has a rear wall of the mouse having an overall dimension less than two inches and the front to rear dimension of the base correspondingly less than the height of the rear wall to maintain the rearward tiltability of the mouse.
The improved computer mouse of the present invention further comprises a disabling means which disables the functionality of the mouse if the mouse is tilted rearwardly such that the flat base of the mouse is lifted off the work surface. This rearwardly tilting of the mouse occurs when the wrist of the user collapses or bends into a compressed position wherein it is susceptible to wrist injuries. In the preferred embodiment of the present invention computer mouse, the disabling means is a springed switch, however other means would function equally as well such as a light sensitive switch, tilt switch, or the equivalents thereof. In another embodiment of the improved computer mouse of the present invention, the disabling means is a sensor. One embodiment incorporates the use of a spring switch operative on a track ball, such that when the track ball is disengaged from the work surface, the switch activates to cease all functions of the computer mouse.
The computer mouse of the present invention further comprises a signal device to warn the user that the mouse is disabled. In the preferred embodiment of the present invention the signal device comprises a signal generator which provides optional audible and optical signals to alert the user the mouse is tilted and therefore disabled. The inventor has suggested the audible alert could be a xe2x80x9cpeepxe2x80x9d or a sound similar to the xe2x80x9cmeowxe2x80x9d of a cat. The optical signal is a plurality of lights positioned to alert the user of the disablement. In any case, the present invention, improved computer mouse comprises a method of detecting when the forward edge of the flat base of the computer mouse is lifted from the work surface, a disabling means to disable the functionality of the mouse when tilted, and also a warning device to inform the user of the disabled status of the computer mouse.
The preferred embodiment of the present invention computer mouse further comprises a plurality of feet on the lower surface of the flat base to facilitate the tracking means.
The improved computer mouse of the present invention can be used with either a standard wire connection to the computer or as a wireless mouse. In the wired configuration the applicant contemplates the wire entering the rear of the mouse above the work surface such that it would not interfere with the rearward tiltability of the mouse in the event that the user""s wrist collapses. In other embodiments the wired configured computer mouse of the present invention, the wire is attached to the mouse on a sidewall of the housing again to prevent the wire from inhibiting the tiltabiltiy of the mouse. The applicant also contemplates in the wired mouse configuration one or more female couplers on the rear wall or sidewalls of the mouse to connect a removable control wire.
The flat base further comprises a tracking means for control of the computer. The computer mouse of the present invention is functional only when the flat base is parallel to a work surface. The tracking means could be a track ball assembly as used on most conventional computer mouse, a motion sensor or any motion tracking device now known in the art, or which may become available in the future. The present invention computer mouse can employ any electronic communication and motion sensing technologies without affecting the novelty and usefulness of the improvements of the applicant""s present invention.


The present invention relates to particles comprising a core, in particular a magnetic core, and a first coating of a first shell material, wherein a second coating of a second shell material is applied to the surface of the first coating facing away from the core, the second shell material is different from the first shell material and has a higher refractive index than the first shell material.

Magnetic particles and in particular magnetic nanoparticles, i.e. magnetic particles with a diameter of less than 300 nm, are of major interest due to their great potential for application in various fields such as, amongst others, catalysis, diagnostics, therapy, water treatment and data storage.
It is known to apply a coating to the particles to protect or stabilize the particles, e.g. against corrosion or agglomeration. A coating can also serve for the further functionalization or modification of the particles for further different applications.
For example, DE 10 2015 118 816 describes anisotropic iron oxide nanoparticles with a diameter of from 3 to 50 nm which are embedded into a silicate matrix and can be used as a component of security features, e.g. in documents or security papers. Nanocrystalline magnetic iron oxide particles which are surrounded by a shell material of natural or synthetic glycosaminoglycans, and the use thereof in medical diagnostics and therapy, are disclosed, for example, in DE 41 17 782 and corresponding U.S. Pat. No. 5,427,767, which is hereby incorporated by reference. Furthermore, EP 1 894 214 and corresponding US2010063263, US2015191718, US2017159043, US2019241885, and US961753, which U.S. publications and patents are hereby incorporated by reference in their entirety, describe a method for the production of silica-coated magnetic particles and the use thereof for the purification of nucleic acids from biological body samples.
It is furthermore known that magnetic particles can generally be used for local indirect heat generation. Thus, magnetic particles which are exposed to an alternating electromagnetic field can convert some of the energy of the alternating field into heat due to hysteresis and relaxation processes. The thermal treatment of tumour cells with remotely controlled inductive heating in the radiofrequency range, wherein the tumour cells are killed by the local effect of heat, represents an example of an application utilizing this effect.
The inductive heat generation capability of magnetic particles can also be used for the debonding of adhesive bonds on demand, so-called debonding-on-demand (DoD). In this context, the debonding of adhesive bonds can be achieved on demand by significantly reducing the strength of the adhesive bond layer by heating.
Thus, for example, WO 2013/034777 and corresponding US 2014329929, US 2014371341, U.S. Pat. Nos. 9,320,686, and 9,668,946, which US publications and patents are hereby incorporated by reference, propose the incorporation of ferromagnetic nanoparticles into dental materials, in particular adhesives and cements, in order to achieve an inductive heating of the dental material by the action of an alternating magnetic field. In the dental field, the debonding of adhesive bonds is important among other things in orthodontics, where brackets which are bonded to the tooth surface to correct malocclusions must be removed again after successful correction without damaging the tooth enamel. Moreover, in the case of repair or complete replacement of high-strength ceramic restorations or crowns which are laborious to remove mechanically, cement bonds that can be easily softened or separated would be advantageous.
However, a disadvantage of the use of magnetic particles in dental materials is often the dark colour of the magnetic particles. In particular, particles the diameter of which is large enough to provide customized magnetic properties for debonding-on-demand applications, such as e.g. an adequate coercivity, are visible to the human eye as a grey or dark spot in the dental material, or lead overall to a darkening of the dental material, which is undesired for aesthetic reasons.
It is indeed known to lighten the colour of magnetic particles through the addition of white pigments. For example, JP 2000/150218 describes the coating of magnetic cores with white pigments. JP 2003/002658 discloses white magnetic particles which are obtained by applying fine magnetic iron oxide particles to the surface of white TiO2 cores. Furthermore, U.S. Pat. No. 5,194,356, which is hereby incorporated by reference, and WO 2010/149150 each describe the incorporation of magnetic particles and white pigments into a polymer matrix.
However, the present inventors have found that magnetic particles that are lightened with pigments, such as e.g. iron oxide particles with a silica-containing coating, and have a nearly neutral colour with only a slightly light-grey shade in air, exhibit a considerably darker colour when embedded in a dental medium, such as dental cement.

Particles with improved colour shielding


Provided is a lane detection system and method. The lane detection method includes extracting feature points of a driving lane from an input road image, extracting candidate start points and candidate end points from candidate control points selected from among the feature points, selecting a left start point and a right start point of the driving lane from among the candidate start points based on information corresponding to a width of the driving lane, and selecting a left end point and a right end point of the driving lane from among the candidate end points based on a number of the candidate control points between each of the left start point and the candidate end points and the right start point and the candidate end points.

1. Field
Apparatus and methods consistent with exemplary embodiments relate to providing a lane detection system and method.
2. Description of the Related Art
With recent advances in information and communication technologies, Lane Departure Warning Systems (LDWS), safe driving assistance systems such as lane keeping, and vehicle auto-control systems have been developed and have been rapidly commercialized.
Lane recognition systems have been touted as a solution for preventing accidents caused by driver distraction. Furthermore, lane recognition systems are also needed to recognize environmental factors in an autonomous driving system.
However, in the lane recognition systems of the related art, a problem of false lane detection exists.


The invention provides methods of preparing a sample of viable diseased cells obtained from a human subject for clinical testing, wherein the methods inhibit anoikis and/or anoikis in the cells while maintaining the physiological functions and genomic composition of the cells when they were in vivo. In the methods of the invention, primary cells are cultured in media comprising at least one anoikis inhibitor, preferably at least one inhibitor of an intrinsic anoikis pathway and at least one inhibitor of an extrinsic anoikis pathway, under anti-anoikis atmospheric conditions, such as greater than 2% and less than 20% oxygen. Method combining multiple culturing conditions, including surface attachment under conditions that inhibit anoikis, are also provided. Compositions and kits for use in the methods of the invention are also provided.

A number of constraints make it difficult to obtain viable human diseased cells suitable for use as a sample in a clinical test when the cells are obtained directly from a human tissue specimen. This largely explains why there are few, if any, clinical tests that use live human cells extracted from tissue. Oftentimes, the preparation of a viable diseased cell sample must be performed at a different location than where the specimen is removed from a patient. This requires that the tissue be transported in a collection container that retains cell viability for an extended period of time. In addition, the amount of diseased tissue available for testing is limited. When the specimen is obtained during a biopsy procedure, 5-10 milligrams or less of diseased tissue may be all that is available. Conventional techniques to extract viable cells from a tissue specimen of this size yield few viable cells. A clinical test requires more than a few viable diseased cells, which would require that the extracted cells to be expanded to have a suitable number representing the tumor of the patient. This presents several additional constraints. First, the time available to expand the cells is limited. Clinical test results are ideally available within several days following the acquisition of the patient specimen to ensure timely selection of an appropriate treatment protocol. In rare cases, a clinical result may still be useful 30 days after a specimen is obtained from a patient. In most cases, the clinical test must be designed to yield a result in less than two weeks to be useful. This requires, ideally, methods to extract and expand a small number of viable cells extracted from a specimen capable of providing a sufficient number of viable diseased cells in less than two weeks.
Furthermore, for the clinical test results to be reliable, the cells must be extracted and expanded in a manner that maintains the distribution of diseased cells found originally in the specimen. This is because any clinical test involving a human specimen requires that a test sample derived from the specimen be representative of the original specimen itself. For instance, a tumor specimen is comprised of different epithelial cell types—luminal, myo, basal, stem—in a certain proportion to each other; a sample obtained from it should include these cell types in roughly similar proportions. However, when a sample of cells obtained directly from a human specimen is extracted and expanded, one cell type may proliferate at a greater rate than the others, or another cell type may not expand at all depending upon the conditions employed. Should that occur, the resulting sample would not be representative of the original specimen and thus may be compromised as a clinical sample.
A related requirement for preparation of a cell sample is that the resulting diseased cells retain their in vivo genomic and physiologic activity profile so that they retain the physiological or genomic characteristics that will be tested. For instance, to measure cell adhesion or cell signaling pathway activity, the cells' pathways ex vivo must retain their in vivo function. Otherwise, the accuracy of a clinical test result would be comprised. Another requirement is that any method used to prepare a cell sample must be capable of yielding testable cell samples from a high percentage of specimens obtained.
Current practices described in scientific literature for acquiring primary cells from tissue for research report less than a 50% success rate in obtaining viable cell samples from tumor tissue (see e.g., Crystal, A. S. et al. (2014) Science 346:1480-1486). The willingness of clinicians to wait up to two weeks for a clinical test result requires the likelihood of a successful test to be high enough to justify delaying treatment of their patient. Since delaying treatment for a patient entails risk, clinicians are unlikely to adopt a clinical test that imposed this risk without a reasonable likelihood that a test result of high utility will be available.
Thus, given the unique requirements of preparing a sample of viable diseased cells for clinical testing—preserving the viability of the cells during a transit period, availability of only a small amount of specimen, the short time available to expand the diseased cells, maintaining cell sample composition consistent with the original tumor, yielding a high percentage of testable cell samples, maintaining physiological and genomic characteristics—there is a need for the development of novel methods of preparing primary cell samples derived from human tissue specimens such that the sample is suitable for use in clinical testing.

Methods of preparing a primary cell sample


A straddle stretching apparatus comprises a seat on top of a support frame and leg support wings which extend from opposite sides of the seat and move outward and upward away from the support frame as a handle at the top of the base is rotated. The handle attaches to rotating means which has struts extending from opposite sides that attach to the side of the leg support wings. The stretching apparatus is used to stretch the muscles of the lower and upper body including the legs, lower back and upper body. Stretch straps are provided on the side of the leg support wings to assist the user in a stretching exercise.

1. Field of the Invention
This invention generally relates to an exercise machine, and in particular to a leg stretching exercise apparatus having a padded seat with a rear cutout, padded leg support wings, a rotating handle for adjustment of the leg support wings, and provides a natural workout position for the user.
2. Description of Related Art
Stretch machines are used by athletes and non-athletes. Athletes typically participate in strenuous exercises and stretching relaxes muscles, prevents cramps and allows a person to loosen up prior to participating in a strenuous activity. Non-athletes include people who need to stretch for rehabilitation purposes or senior citizens who need to stretch due to circulation problems.
Many stretch machines in the prior art require the user to sit down on the floor and workout in an unnatural position. This often presents a problem for people that need to stretch for rehabilitation purposes or for senior citizens who need to stretch for circulation problems. The sit-down machine often limits the muscles that need to be stretched.
In the prior art, various approaches have been taken to provide a stretch machine. In U.S. Pat. No. 4,647,040, issued Mar. 3, 1987 to Ted R. Ehrenfried and assigned to Treco Products, Inc., a leg stretching apparatus is disclosed whereby an operator sits on a torso restraining means such as a seat assembly and a base assembly. The operator's legs are placed in the leg supporting means which are spread apart through the action of a crank and a pivoting of a crank assembly housing which includes a worm gear. However, this machine requires the user to sit down and it does not allow the user to stretch in a natural position.
In U.S. Pat. No. 5,507,711, issued Apr. 16, 1996 to Michael Richardson, a leg stretcher exercise machine is disclosed for sitting in an upright position having a centrally located padded seat and padded wings or leg platforms which are hingedly mounted on opposite sides of the seat with removable hinge pins for quick connect and disconnect from the seat. A hydraulic jack is mounted on the frame below the seat. A pump arm attached to the jack allows the user to raise the leg platforms, and a release valve control arm is provided for lowering the leg platforms. However, this exercise machine does not allow the stretcher to stretch in what is referred to as the hurdler's stretch.
In U.S. Pat. No. 4,844,453, issued Jul. 4, 1989 to Gary P. Hestilow, and assigned to Century Martial Art Supply, Inc., a stretching machine for stretching the legs of an individual is disclosed comprising a seat with an adjustable back and a pair of leg bars. The leg bars have a pivot end and an opposite a termination end. Each of the leg bars is connected to a hydraulic jack having a jack handle for moving the leg bars to stretch positions. A release rod deactivates the hydraulic jack to move the leg bars back to the rest position. Leg decks attach to the leg bars, and leg pads and thigh pads are provided. However, this stretching machine does not allow the user to stretch in what is referred to as the Chinese split or the hurdler's stretch.
In U.S. Pat. No. 5,520,598, issued May 28, 1996 to Oscar L. Little, a leg exercising machine having handlebars attached to a vertical support by means of a pin is disclosed. Mounted on the frame is a lower leg exercise device having a planar base member attached to the base frame, distal end plates, weight posts, two track assemblies with a wheeled platform extending horizontally from the base frame. A person standing with a foot on each platform slides the platforms back and forth along the track assemblies by alternately flexing and relaxing arms and outer muscles in the person's upper legs. A handle bar assembly is adjustably attached to the vertical support. This exercise machine requires the user to sit down, and it does not have any support for the user's body weight allowing a safe, comfortable stretch.
In U.S. Pat. No. 5,800,323, issued Sep. 1, 1998 to Cliff Ansel, an adjustable hip and thigh exercise apparatus 20 with padded handlebars is disclosed. The apparatus is attached to a wall and aligned with the pivot point of a user's hip. However, this exerciser has no seat.
Therefore, it is desirable to have a leg stretching exercise machine of minimum cost and high durability that allows the user to sit comfortably in an upright position and easily adjust leg supports to a stretching position.


A method for imaging includes acquiring surface image data for a target using a first imaging modality. A visual representation of the target based on the surface image data is generated. Internal image data for the target is acquired using a second imaging modality. During acquisition of the internal image data, the visual representation of the target based on the acquired internal image data is updated.

Medical imaging devices provide non-invasive methods to visualize the internal structure of a patient. Such non-invasive visualization methods can be helpful in treating patients for various ailments. For example, the early detection of cancer or tumors in a patient can be important in treating that patient, and may increase survival probability of patients.
Ultrasound imaging, a non-invasive medical imaging technique, uses sound waves, typically produced by piezoelectric transducers, to image a tissue in a patient. The ultrasound probe focuses the sound waves, typically producing an arc-shaped sound wave which travels into the body and is partially reflected from the layers between different tissues in the patient. The reflected sound wave is detected by the transducers and converted into electrical signals that can be processed by the ultrasound scanner to form an ultrasound image of the tissue.
The typical procedure followed to obtain ultrasound images of a patient's breast involves positioning a patient in a supine position upon a table, applying a gel or other acoustic couplant to the patient's breast, and passing an ultrasound transducer across the patient's breast. As the transducer traverses the breast, ultrasound images can typically be viewed in real-time on a display of an ultrasound system. The ultrasound transducer may be either a hand-held transducer which is manually manipulated by the imaging technician, or may be an automated scanning device, such as that described in U.S. Pat. No. 7,731,662. While ultrasound scanning has desirable sensitivity in detecting internal structures, a handheld ultrasound probe suffers generally poor location specificity. For instance, one drawback of such methods lies in the fact that the breast is a very malleable structure; the geometry and structures of the breast move and change whenever the patient changes position. Thus, accurate and thorough scanning of the breast with an ultrasound probe is difficult to achieve.

Synchronized surface and internal tumor detection


A fluid cartridge for a printing device includes a housing having a base and a first and second chamber. A wall extends outwardly from and substantially normal to the base and is configured to separate the housing, thereby forming the first and second chambers. An air/ink exchange port is defined in a bottom portion of the wall and adjacent to the base. A longitudinal air flow-restricting member is disposed adjacent the air/ink exchange port and on the base, and extends outwardly predetermined distance into one of the first or second chambers.

The present disclosure relates generally to fluid cartridges, and more particularly, to a fluid cartridge for a fluid supply system.
Inkjet printers often use replaceable fluid cartridges to supply ink and/or other fluids to a printing device to form an image on print media. Some fluid cartridges include two or more internal chambers configured to hold the ink, where the chambers are often separated by a wall having an air/ink exchange port formed therein. The air/ink exchange port provides air and/or ink communication between the chambers. The ink is selectively taken from one or more of the chambers and delivered to and ejected through nozzles of a printhead and then onto the print media. In some instances, however, fluid may continue to flow through the printhead even when the printhead is not actuated by the printer.
To prevent the free flow of ink during non-use of the printhead, a negative or back pressure is formed in the ink within the cartridge that overcomes the pressure at the printhead when the printhead is not in use. Thus, a vacuum is formed in the free ink chamber of the cartridge and holds the ink therein. The back pressure within the free ink chamber of the cartridge is generally maintained by capillary force and the flow of air and/or ink back and forth through the air/ink exchange port. Difficulties may arise, however, in maintaining the back pressure in the cartridge when additional, unintended air enters the air/ink exchange port from various leak regions that may form during construction of the fluid cartridge.
Further difficulties may arise from a lack of desirable back pressure. For example, if one cartridge fails to provide sufficient back pressure, the ink may drool out the nozzles onto the orifice plate, and then may be drawn up by back pressure of another color cartridge. This may result in undesirable color mixing.

Fluid cartridge for a fluid supply system

Hewlett-Packard Development Company, L.P.


Composite membranes, methods or processes for producing composite membranes, and systems utilizing composite membranes are generally described. In some examples, a composite membrane includes a porous halogenated polymer and a conductive polymer coupled to the porous halogenated polymer. In some examples, a process for producing a composite membrane includes coupling a conductive polymer and a porous halogenated polymer.

In recent years, a variety of wastewater treatment technologies have emerged, which use chemical, physical chemical, and biological methods to remove contaminants from wastewater.
Membrane water filtration technology has been increasingly used in contaminant removal systems due to its high efficiency, relatively low energy usage, simplified equipment and ease of operation. New membranes are the focus of continuous R&D efforts, such as ultra-filtration membranes, microfiltration membranes, nano-filtration membranes, ceramic membranes and ion-exchange membranes. These membranes may not only fully recover valuable resources in wastewater, but also advance the depth of wastewater treatment with significant environmental and economic benefits. However, the complexity of the manufacturing process, their relatively high price, and possibility of secondary contamination limits the widespread applications of membrane separation technology in wastewater treatment. Furthermore, at present, membranes with dual functions of filtration (of water impurities) and adsorption (of heavy metal ions) remain untapped.
The membranes used in wastewater treatment have to withstand rather harsh chemical conditions. Materials such as polytetrafluoroethylene (PTFE) for example, exhibit good resistance to chemical corrosion and are hydrophobic, are insulating, insoluble and exhibit non-adhesive or "anti-sticking" properties. PTFE films have been mainly used in gas-solid separation, dust collection, air purification, and as porous waterproof coatings on clothing. However, because of their strong hydrophobicity, PTFE films cannot be used in water filtration. Therefore, to produce PTFE composite membranes for use in water filtration, the PTFE films are typically subjected to plasma processing followed by grafting modification of hydrophilic functional monomers. The PTFE films can also be irradiated and compounded together with hydrophilic polymers. However, these processes are both complex and costly. Furthermore, plasma treatment of the PTFE films may undermine the internal structure of the membrane and decrease the membrane mechanical strength.
Another known process for producing composite membranes for use in water filtration employs electro-polymerization to polymerize hydrophilic monomers onto a non-conductive polymer support. However, due to the non-conductive nature of such polymer supports, the rate of electro-polymerization is comparatively lower than that of chemical polymerization. Furthermore, the extent of electro-polymerization is limited by the size of the electrode used. Therefore, such processes are difficult to scale-up and have limited industrial applications.


An article handling apparatus for a trim press includes a die and a cooperating punch configured to sever articles from a web, a treadle configured to move relative to the die, and a drive wheel assembly configured to move the web and the articles. The drive wheel assembly includes a pair of roller feed assemblies. Each of the roller feed assemblies include a knock-lever mechanism having a lever arm and a follower wheel, the lever arm being configured to contact the die as the treadle is moved towards the die. The the follower wheel is configured to retract from the respective drive wheel in response to contact of the lever arm with the die.

Various devices are known for trimming thin-walled articles from sheets of thermoformed plastic material. The trimming or severing of such articles from a continuous sheet of thermoformable plastic and/or foam material has long been known in the art. Additionally, sheet guides and mechanical treadles are known for moving the sheet and articles for intermittent severing between coacting punches and dies of a trim press.
U.S. Pat. No. 4,173,161 discloses a mechanical trim press that includes a mechanical treadle having feed fingers mounted on the treadle. The feed fingers comprise a mechanical linkage that interacts with projecting integral tabs formed in the sheet to advance the sheet to a die in step-bystep movement that is mechanically synchronized with the stroke of the punch. The treadle also includes opposed pairs of vertical guide strips between each article. Each guide strip is carried by a spacer that is mounted onto a cross frame member of the treadle. Opposed pairs of guide strips, provided between each adjacent pair of formed articles in the sheet, are spaced apart slightly from each other by a distance slightly greater than the thickness of the sheet passing therebetween. However, such close spacing coupled with the use of guide strips between every adjacent pair of articles results in increased frictional forces which tends to result in mis-feeding and jamming of the treadle, particularly when running the treadle at relatively high product feed rates.


A sensory aroma glass is disclosed. According to one embodiment, an apparatus comprises a fluid barrier; and a fluid container designed for containing a fluid. The fluid barrier is in contact with the rim or internal or external sidewall of the fluid container. The fluid barrier extends into the fluid container. The fluid barrier has an opening that allows aroma of the fluid to escape from the fluid container without allowing the fluid to escape from the fluid container.

Prior devices include a variety of drinking vessels that allow for improved olfaction from the vessel during consumption of a beverage, and vessel covers which prevent insects from contacting the liquid contents.
One prior device is a drinking glass having the dual purpose of providing, in addition to drinking therefrom, the ability to sample the aroma emitted from the beverage. The device has at least one inner element inside the drinking glass dividing the glass into a drinking compartment and an aroma compartment. This allows the aroma of the beverage to be sampled from the aroma compartment while consuming the beverage from the drinking compartment.
Another prior device is a drinking glass which allows for improved olfaction from the glass in addition to drinking therefrom. The rim of the glass has a cut-out section to create a facial profile to receive the nose.
Another prior device is a cover for a container which will allow liquid contents to exit while preventing intrusion of insects. The cover has a plastic screen which is attachable and detachable from the upper rim of the container.
Another prior device has an improved cover for a container which allows liquid contents to exit while preventing the intrusion of insects. The cover has an annular guard formed with a downwardly extending skirt and an orthogonally upwardly positioned rim including a screen matrix tapering downwardly to meter flow of beverage through the openings.

This patent is subject to a terminal disclaimer.


An intermediate cover is used to cover the surface of a guide rail existing between first and second sliders arranged on the guide rail of a linear guide device. The intermediate cover is structured such that it includes on the two ends thereof two mounting portions respectively for mounting the two ends of the cover onto the two sliders, and it also includes a body portion having a U-shaped section and including an upper surface and two side surfaces located adjacent to the upper surface and two side surfaces of the guide rail.

The present invention relates to a dustproof cover for covering a guide rail of a linear guide device and, in particular, to an intermediate cover for covering the portion of a guide rail existing between two sliders when a plurality of sliders are provided on the guide rail.
When a linear guide device is assembled into a machine table, in most cases, normally, as shown in FIG. 14, four sliders 2 are mounted on the lower surface of a machine table T. That is, two sliders 2 are assembled onto a guide rail 1 to form one assembly and two other sliders 2 are assembled onto another guide rail 1 to form another assembly, while the two assemblies are fixed onto a machine base D in parallel to each other.
Foreign substances such as welding powder, chips, cutting oil, dust and the like are readily adhere to the linear guide device LG structured in this manner for supporting the machine table T. If such foreign substances are stuck to the guide rail especially to the upper and side surfaces of the guide rail 1, then they penetrate into the interiors of the moving sliders 2. In the interiors of the sliders 2, a large number of rolling members move endlessly while they roll within precisely machined loaded roller rolling passages each consisting of roller rolling grooves 3 formed on the side surfaces of the guide rail 1 and roller rolling grooves (not shown) formed on the inner surfaces of the sliders opposed to the guide rail 1 side surfaces, thereby allowing the sliders 2 to move smoothly. The penetration of the foreign matter into the interiors of the sliders 2 can interfere the smooth rolling movements of the rolling members and thus can worsen the movement precision and the like of not only the sliders 2 but also the machine table T. Therefore, taking proper dustproofing measures in the guide rails is one of the important technical items.
In a conventional guide rail, as means for preventing the guide rail against dust, as shown in FIG. 15, in most cases, bellows 5 and 6 are used. To provide such bellows, Neoprene rubber is coated on the two side surfaces of nylon fiber cloth and further a reinforcing polyester film is adhered to the above to thereby form a sheet. The sheet is folded in a wave form in such a manner that it is freely expandable and contractible, and then two steel plates are respectively mounted to the two ends of the sheet. The bellows 5 respectively provided in the rail end portions are mounted in such a manner that one end of each of the bellows 5 is tapped and fixed to the one end face portion of the guide rail 1 by a screw, while the other end thereof is screwed to the outer end face of the slider 2. On the other hand, the bellows 6, which serves as an intermediate cover for covering the intermediate portion of the guide rail 1 existing between the two sliders 2 and 2, as shown in FIG. 16, is mounted in such a manner that one end thereof is screwed to the inner end face of one slider 2 by a mounting screw 7 while the other end thereof is similarly screwed to the inner end face of the other slider 2 (FIG. 17).
However, in the above-mentioned conventional bellows 6 serving as an intermediate cover, as shown in FIG. 18 in which the bellows portion of FIG. 17 is viewed from below, the lower portions of the bellows are open so that large gaps 8 are formed in continuous waves between the guide rail 1 and the bellows lower portions. That is, foreign substances are can invade the guide rail 1 through these gaps 8.
Also, since the bellows are formed in waves the crown and valley portions thereof to continue with each, the bellows 6 occupies most of a U-shaped space existing between the upper surface 1a and two side surfaces 1b of the guide rail 1 and the upper surface 2a and two side surfaces 2b of the slider 2. This interferes with a space which is necessary to arrange an oil feed pipe for supply of lubricating oil to the linear guide device LG and other attached devices.
Further, when the linear guide device LG is used in such a manner that it is mounted horizontally or vertically on a wall, or when it is used in such a manner that it is mounted to a ceiling upside down, the bellows 6 hangs down so that it cannot protect the guide rail from dust completely, or the bellows 6 can come into contact with other portions of the linear guide device LG.
Moreover, in the conventional bellows, when the end portions thereof are screwed to the slider, as shown in FIG. 16, it is necessary that the mounting screw 7 be inserted into a screw hole 9 formed in the cover end portion from inside of the bellows 6, and it is then threadably engaged into a screw hole formed in the end face of the slider 2, before it is tightened. Thus, the conventional bellows is difficult to mount.
In addition, the bellows is expensive and the durability thereof is not satisfactory.

Intermediate cover for use in a linear guide device


An engine has a pair of a pair of parallel crankshafts having a cross shaft connected at one to a journal on one of the crankshafts. The cross shaft has a slot in which a distance compensator mounted on a journal of the other of the crankshafts oscillates. A piston connecting rod is attached to the cross shaft at an intermediate portion of the cross shaft. The crankshafts rotate in the same direction and at the same speed; however, the one of the crankshafts is advanced with respect to the other. The journals are located at different radiuses.

The cross shaft is the background for this invention. The cross shaft has a slot in one end where a crankshaft journal is mounted with a distance compensator which travels in the slot.
Because of the way the cross shaft is formed, it can be energized by a standard internal combustion piston and connecting rod 18 degrees before the crank reaches top dead center. At this position, the engine gives a good amount of usable torque.
The other end of the cross shaft is secured to a crankshaft. This crankshaft has to be timed with the compensated crankshaft. The length of the radius on the two crankshafts, the timing of the two crankshafts, and the form of the cross shaft slot will govern the torque characteristics of the engine. This gives the advantage of a longer crankshaft power stroke per length of piston travel than any other engine.
The improvement of performance bit the distance compensated cross shaft engine over the way engines are being made today should be numerous. The reason for presenting this invention is because it should gennerate more horsepower while using less fuel, it will produce a cleaner exhaust. It should produce more horsepower because it has a longer distance on the crank travel on which power is applied.
There is more fuel economy because the longer power distance on the crank travel is done with a piston travel shorter than the longer power distance on the crank travel. A cleaner exhaust because of a longer time the burning fuel will stay in the combustion cylinder.
The difference between my invention and the Mandella invention is that before top dead center, my engine can start the power stroke. My engine at this advanced firing position has a large amount of usable torque. Mandella, at top dead center position, has a zero torque situation.
No other piston driven engine has torque as far ahead of top dead center position as my invention. This is a huge advantage for power and economy. My invention is very different than the Mandella invention. Because mine has less moving parts and the parts are totally different than the Mandella parts.
The concept of my invention is for torque and economy and not for inventing a mechanical adjustment for piston height. The new idea in my invention is the cross shaft with a slot wherein the distance compensator runs. This is what sets my invention apart from all the other multi-shaft engine inventions. The cross shaft concept is the invention. No other engine patent has the cross shaft with a slot and distance compensator concept. No other engine patent can give an engine the same advantages and characteristics as the cross shaft, slot, and distance compensator concept.
This is design gives many opportunities for different motor characteristics. These can be brought about by different cross shaft angles and curves in the distance compensator slot. The best part of the cross shaft invention is that it can apply usable torque to the crankshaft before top dead center.
The cross shaft can apply a changing attitude of push on the crank journal through the power stroke which applies power to turning the crank rather than stressing the engine block.