The present invention is directed to rotational stabilizer pads for stabilizer arms of vehicles. The stabilizer pads include first and second ground contact faces for contacting respectively a smooth ground surface and a rough or gravel ground surface. In embodiments of the present invention, the stabilizer pads include a reversible resilient pad coupled to a first flange and a second flange. The first and second flanges may include grouser points for engaging the rough ground surface. Further features include a releaseable latch mechanism and offset pad construction.

The present invention relates generally to stabilizer pads for vehicles, and more particularly to pivotally mounted stabilizer pads. In the majority of the constructions disclosed herein the stabilizer pads are reversible having a generally flanged first surface for engagement with a soft irregular ground surface such as gravel, and having a resilient second surface for engagement with a smooth hard ground surface such as concrete or asphalt.
FIG. 1 is a fragmentary view of a typical loader/backhoe 10 having a shovel mechanism 12, stabilizer arms 14 and 16, and associated stabilizer pads 18 and 20, respectfully. Hydraulic pistons 15 are used to operate each of the stabilizer arms 14 and 16 independently. In FIG. 1, the stabilizer arms are in an operational, extended position with the stabilizer pads 18 and 20 in engagement with the ground surface to prevent movement of the backhoe during operation of the shovel mechanism 12. When the backhoe 10 is to be moved, the pistons associated with each cylinder are withdrawn so that the stabilizer arms 14 and 16 pivot and raise the stabilizer pads above ground level.
The stabilizer pad 18 of FIG. 1 is shown in greater detail in FIGS. 2 and 3. Stabilizer pad 20 is substantially identical to stabilizer pad 18. The stabilizer pad 18 and similar stabilizer pads are further described in U.S. Pat. Nos. 4,889,362, 5,054,812, 5,466,004, 5,547,220 and 5,667,245, each of which is issued to the inventor of the present application and incorporated herein by reference. The stabilizer pad 18 includes a flat plate 22 having flanges 24 and 26, both extending from one surface of plate 22. The stabilizer pad 18 is also provided with supporting webs or ribs 25, one associated with each flange. The ribs 25 provide additional support for the flanges 24 and 26. The plate 22 is notched at 30 between flanges 24 and 26 as illustrated in FIG. 1. The plate is notched to accommodate the arm 14 and to enable reversible rotation of the stabilizer pad.
The stabilizer arm 14 includes a journal end for accommodating pin 34. Pin 34 also fits within holes of flanges 24 and 26. The pin is used to secure the stabilizer pad to the arm using, for example, a cotter pin as illustrated in FIG. 3.
On the side of the flat plate 22 opposite that containing the flanges 24 and 26 are disposed three laminated rubber pads 40. Each of the rubber pads 40 includes laminated rubber sections supported between angle irons 44 and 48. The angle irons 44 and 48 have a base leg and an upright leg. Each of the upright legs has holes therein for receiving elongated securing pins 50 for containing the laminated rubber sections between the angle irons. The laminated pads 40 are secured to the plate 22 using bolts 53 and nuts 55.
The stabilizer pads 18 and 20 are rotatable about pin 34 when the stabilizer arms are in the raised position to place either the rubber pads 40 downward for engagement with the ground or to place the flanges 24 and 26 downward for engagement with the ground.
In typical operation, the rubber pad side of the stabilizer pad 18 is positioned to engage the ground, as shown in FIG. 1, when the ground surface is a relatively flat hard surface such as concrete or pavement. The flange side of the stabilizer pad 18, as shown in FIG. 2, is positioned to engage the ground when the ground surface is an unfinished ground surface, such as gravel or dirt. The flanges are designed to dig into the unfinished ground surface to anchor and stabilize the backhoe.
Although the prior art, reversible stabilizer pads described above provide reliable operation, it is desirable to provide a simplified stabilizer pad with improved operational performance over the stabilizer pads described above.
In one general aspect, the invention features a stabilizer pad for use with a stabilizer arm. The stabilizer pad includes a frame having a base plate and first and second flanges extending from a first surface of the base plate. Each of the first flange and the second flange has at least one grouser point to engage a ground surface. The frame, including the base plate, the first flange and the second flange, is formed using a continuous, substantially U-shaped piece of material. The stabilizer pad further includes a resilient pad mounted to a second surface of the base plate, opposite the first surface of the base plate.
The resilient pad can be constructed and arranged such that it covers substantially all of the second surface of the base plate, and the resilient pad can include a plurality of rubber strips. The stabilizer arm can include a pin for rotatably mounting the stabilizer pad to the stabilizer arm, and each of the first and second flanges can include a mounting hole to receive the pin. The resilient pad can be a reversible resilient pad having a first substantially smooth surface to engage a ground surface, and a second substantially smooth surface to engage a ground surface, the first surface being substantially parallel to the second surface. The stabilizer pad can further include a mounting bracket that is constructed and arranged to mount the resilient pad to the frame such that either the first surface of the resilient pad or the second surface of the resilient pad is in contact with the second surface of the base plate. Each of the flanges can have a pair of grouser points to engage a ground surface, and for each pair of grouser points, a first grouser point of the pair can extend a greater distance from the base plate than a second grouser point of the pair. The stabilizer pad can further include means for preventing inadvertent rotation of the stabilizer pad about the pin.
In another general aspect, the invention features a stabilizer pad for pivotally coupling to a stabilizer arm of a vehicle such that the stabilizer pad can rotate about a rotation axis to allow either a first ground contact face of the stabilizer pad or a second ground contact face of the stabilizer pad to engage a ground surface. The stabilizer pad includes a frame having a base plate, a first flange and a second flange, the base plate having a first surface and a second surface, the first and second flanges being coupled to the base plate and extending in a direction substantially perpendicular to the first surface of the base plate. The stabilizer pad further includes a resilient pad mounted to the base plate, the resilient pad extending over substantially all of the second surface of the base plate.
The resilient pad can include a plurality of rubber strips. The stabilizer arm can include a pin for mounting the stabilizer pad to the stabilizer arm, and each of the first and second flanges can include a mounting hole to receive the pin. The resilient pad can be reversible and have a first substantially smooth surface to engage a ground surface, and a second substantially smooth surface to engage the ground surface, the first surface being substantially parallel to the second surface. The stabilizer pad can further include a mounting bracket that is constructed and arranged to mount the resilient pad to the frame such that either the first surface of the resilient pad or the second surface of the resilient pad is in contact with the second surface of the base plate. Each of the flanges of the stabilizer pad can have a pair of grouser points to engage a ground surface, and for each pair of grouser points, a first grouser point of the pair can extend a greater distance from the base plate than a second grouser point of the pair. The stabilizer pad can further include means for preventing inadvertent rotation of the stabilizer pad about the pin. The resilient pad can be formed using at least one rubber strip having a slot formed therein, and the base plate can extend through the slot in the rubber strip.
In yet another general aspect, the present invention features a rotatable stabilizer pad for use with a stabilizer arm. The rotatable stabilizer pad includes a base plate having a first surface and a second surface, the second surface being substantially parallel to the first surface, and first and second flanges, coupled to the base plate and extending from one surface of the base plate. Each of the flanges has a pair of grouser points to engage a ground surface, and for each pair of grouser points, a first grouser point of the pair extends a greater distance from the base plate than a second grouser point of the pair. The stabilizer pad can further include a resilient pad mounted to the base plate, and the resilient pad can have an engaging surface to engage a ground surface, the engaging surface being substantially parallel to the second surface of the base plate.
In another general aspect, the invention features a reversible resilient pad for a stabilizer pad of a stabilizer arm. The resilient pad includes a resilient body portion having a first substantially smooth surface to engage a ground surface, and a second substantially smooth surface to engage a ground surface, and means for coupling the resilient body portion to the stabilizer pad such that either the first surface or the second surface can be selected as a contact surface and be positioned to contact the ground surface. The resilient body portion can include a plurality of rubber strips.
In another general aspect, the invention features a reversible resilient pad for a stabilizer pad of a stabilizer arm. The reversible resilient pad includes a resilient body portion having a first substantially smooth surface to engage a ground surface, and a second substantially smooth surface to engage a ground surface, the first surface being substantially parallel to the second surface. The reversible resilient pad further includes at least one mounting bracket coupled to the resilient body portion for coupling the resilient body portion to the stabilizer pad.
The at least one mounting bracket can include a first bracket mounted to a first side of the body portion between the first surface and the second surface, and a second bracket mounted to a second side of the body portion between the first surface and the second surface. The first bracket and the second bracket can be constructed and arranged to provide reversible mounting of the resilient pad to the stabilizer arm to allow either the first substantially smooth surface or the second substantially smooth surface to contact a ground surface.
In another general aspect, the invention features a stabilizer pad for a stabilizer arm of a vehicle. The stabilizer pad includes means for pivotally coupling the stabilizer pad to the stabilizer arm of the vehicle such that the stabilizer pad can rotate about a rotation axis to allow either a first ground contact face of the stabilizer pad or a second ground contact face of the stabilizer pad to engage a ground surface, a first flange and a second flange, each of which is coupled to the means for pivotally coupling, a resilient pad, and means for coupling the resilient pad to the first flange and the second flange.
The resilient pad can be a reversible resilient pad having a first substantially smooth surface to engage the ground surface, and a second substantially smooth surface to engage the ground surface, the first surface being substantially parallel to the second surface. The means for coupling can include means for arranging the reversible resilient pad such that either the first surface of the resilient pad or the second surface of the resilient pad is positioned to contact the ground surface. Each of the flanges can have a pair of grouser points to engage a ground surface. The means for pivotally coupling can allow rotation of the stabilizer pad such that either the grouser points or the resilient pad is positioned to engage the ground surface. The stabilizer pad can further include means for preventing inadvertent rotation of the stabilizer pad about the axis of rotation.
In another aspect of the present invention there is provided a stabilizer pad for use with a stabilizer arm. The stabilizer pad comprises a frame of multiple members including a first member defining a first ground contact surface extending generally along a first plane, and a second member having a surface extending generally along a second plane. The first and second planes are arranged in a non-parallel relative position. A resilient pad is provided and mounted to the second member surface and defines a second ground contact surface different than said first ground contact surface. The first and second ground contact surfaces are also arranged in a non-parallel relative position. The first member comprises at least a first flange and the second member comprises a base plate. The resilient pad has a first substantially flat surface to engage a ground surface and a second substantially flat surface to engage a ground surface. The first substantially flat surface is substantially parallel to the second flat surface. The pad also includes means for coupling the resilient pad to the frame so that either the first surface or the second surface can be selected as a contact surface and be positioned to contact the ground surface.
In accordance with still a further aspect of the present invention there is provided, in a stabilizer pad for use with a stabilizer arm, an improved resilient pad member that is comprised of a resilient body portion having a first ground engageable surface extending generally along a first plane, and a second ground engageable surface extending generally along a second plane. The first and second planes are spaced from each other and disposed substantially in parallel relative position. Means are provided for coupling the resilient body portion to the stabilizer pad such that one of the first and second ground engageable surfaces can be selected and be positioned to contact the ground surface while the other of the first and second ground engageable surfaces is disposed spaced above and substantially in parallel to the ground surface. The means for coupling enables either, but only one at a time, of the ground engageable surfaces to be in contact with the ground surface. The resilient body portion may include a plurality of rubber strips.
In accordance with still a further aspect of the present invention there is provided a stabilizer pad for use with a stabilizer arm. The pad comprises a support piece and means for pivotally retaining the support piece from the stabilizer arm. The resilient pad has at least one upstanding portion engageable with a slot in the support piece. Retaining means are provided for securing the resilient pad to the support piece. The support piece may include an upright flange and a base piece having multiple slots for receiving multiple upstanding portions of the resilient pad.
In accordance with another aspect of the present invention there is provided a stabilizer pad for use with a stabilizer arm. The pad comprises a support piece and means for pivotally retaining the support piece from the stabilizer arm. A resilient pad is provided having at least one slot therethrough and defining first and second opposed ground engaging surfaces. The support piece has at least one base support member engaging the slot for support of the resilient pad from the support piece with one of said ground engaging surfaces disposed in a ground engaging position. The support piece may actually comprise a pair of base support pieces engaging with a corresponding pair of slots in the resilient pad. In this particular aspect of the invention the resilient pad is reversible by removing retaining means and reversing the pad through a 180xc2x0 rotation. A circular or hexagonal shape could be revolved in smaller degrees of rotation such as 30xc2x0, 45xc2x0 etc and then secured also.
In accordance with a further aspect of the present invention there is provided a stabilizer pad that comprises a support piece and a resilient pad supported from the support piece. The support piece has a cam and there is also provide a releasable resilient latch supported from the stabilizer arm and adapted to engage the cam to hold the latch in a locked position. The latch is constructed of a resilient material and manually operable so as to move to an unlocked position, disengaging from the cam to permit rotation of the pad. The releasable latch is preferably held in a locked position while grouser points of the pad are in engagement with a ground surface.
In accordance with a further aspect of the present invention there is provided a stabilizer pad assembly that is comprised of a pair of laterally spaced apart plate members with the plate members being pivotally attached to a stabilizer arm by a pin extending laterally between spaced surfaces of respective plate members. At least one resilient pad is formed with multiple peripheral surfaces and with at least one passage extending transversely therethrough between opposite sides thereof. At least one mounting member is provided extending through the passage in the resilient pad. The mounting member has at least one end portion secured to at least one of the plate members so as to support the resilient pad from that plate member. A fastener is engageable between the resilient pad and the plate member. This fastener is removable to permit the resilient pad to be rotatable between the multiple peripheral surfaces and to be re-engagable so as to permit selective positioning of any one of the multiple peripheral surfaces for use as a working surface for ground engagement.
In accordance with further aspects of the present invention there may be a plurality of separate resilient pads and a like plurality of mounting members. The mounting members may position the resilient pads with opposite ends thereof disposed between the pair of plate members. The mounting members preferably position the resilient pads spaced from one another. The mounting member may comprise a shaft. The resilient pads may be of cylindrical shape with the mounting member extending through a passage at substantially the center axis of the cylindrical resilient pad. The cylindrical pad may have multiple, peripherally-disposed, through holes corresponding in number to the number of multiple peripheral surfaces and for receiving the fastener extending through a selected one of the holes between plate members to position one of the multiple surfaces for use as the working surface.
In accordance with further aspects of the present invention the mounting member may be in the form of a bolt and the fastener may also be in the form of a bolt. Each resilient pad may be of multi-sided, cross-section including, for example, a square cross-section or a triangular cross-section. Each of the resilient pads may be of single piece construction or may be comprised of multiple stacked pad segments. There may be provided a base wall interconnecting the spaced apart plate members and disposed between the pin and the resilient pad. The base wall and parts of the plate members form a pocket for receiving multiple resilient pads. The plate members may also have grouser points.
In accordance with still further versions, the pad may comprise a pair of laterally spaced apart plate members with the pair of plate members being pivotally attached to a stabilizer arm by a pin extending laterally between facing surfaces of the respective plate members. At least one resilient pad is provided formed with multiple peripheral surfaces, and with at least one passage extending transversely therethrough between opposite sides of resilient pad. At least one mounting member is provided extending through the passage in the resilient pad. The resilient pad passage and mounting member have like non-circular cross-sections. A fastener removeably engageable with the mounting member is removable to permit the resilient pad to be rotatable between the multiple peripheral surfaces and re-engagable so as to permit selective positioning of any one of the multiple peripheral surfaces for use as a working surface for ground engagement.
In accordance with further aspects of the invention, there may be provided a plurality of separate resilient pads and a like plurality of mounting members. The mounting members may position the resilient pads with opposite ends thereof disposed between the pair of plate members. The mounting members may position the resilient pads spaced from one another. The mounting member may comprise a shaft that extends between spaced apart plate members. The shaft is of multi-sided cross-section and may be, for example, triangular or square in cross-section. The combination of the passage in the pad as well as the configuration of the shaft provides indexing for the pad supported from the plate members.
In accordance with still a further version of the present invention there is provided a stabilizer pad assembly that comprises a pair of laterally spaced apart plate members, a pin extending between the plate members for providing pivotal support of the plate members from a stabilizer arm and a resilient pad formed with upper and low substantially planar surfaces, and with at least one passage extending transversely therethrough between opposite sides thereof. At least one mounting member extends through the passage in the pad and is fixedly supported from at least one of the pair of plate members. A clamp bar is spacedly disposed from one of the plate members and arranged on the side of that plate member opposite to the other plate member. The clamp bar is for retaining one side of the resilient pad. At least one securing piece is provided extending through the clamp bar and the resilient pad and for securing the resilient pad to the one plate member with the resilient pad retained between the clamp bar and the one plate member.
In accordance with still further versions of the present invention the clamp bar may have a curved cross-section so that when it is clamped it provides a vice action on the resilient pad. There may be a pair of mounting members. The securing piece may comprise at least one bolt that is for securing the resilient pad to the one plate member. There may also be provided another resilient pad, clamp bar, and pair of mounting members for securing the other resilient pad to the other plate member, whereby both resilient pads are on the outside of the respective plate members.
In accordance with another aspect of the present invention there is provided a stabilizer assembly for earth moving apparatus and in which the stabilizer pad is oriented in a different manner than existing systems so as to provide a more stable construction. The stabilizer pad assembly may be considered as having a front-to-back axis and a side-to-side axis and includes at least one substantially vertical stabilizer arm and a stabilizer pad secured to the lower end of the stabilizer arm for engaging a work surface beneath the stabilizer arm. The stabilizer pad comprises a plate mounted on the lower end of the stabilizer arm and a pad member which is usually resilient and which is removeably mounted to the plate on the lower side thereof facing the work surface. The plate is of multi-sided shape having a first side dimension transverse to and greater in length than a second side dimension. The plate is mounted to the stabilizer arm so as to position the orientation of the plate with its first side dimension extending parallel to the front-to-back axis of the earth moving apparatus. This essentially orients the stabilizer pad 90xc2x0 from its previous orientation. The long dimension of the pad extends in the front-to-back direction. This construction centers the stabilizer arm on a long edge of the stabilizer pad instead of on a short edge and is thus more centered on the pad. This construction reduces excessive wear along one edge, and more evenly spreads the load over the entire lower surface of the pad.
In another aspect of the invention, there is provided a removeable pad assembly which is comprised of laminated layers of a resilient material such as rubber. The orientation of the rubber layers is vertical or perpendicular to the ground surface. The orientation of the layers may be either parallel to the front to back direction of the earth moving equipment or transverse thereof, depending upon the use of the equipment or wear characteristics desired. The pad assembly includes a bracket and pins which are mounted onto the underside of the stabilizer pad and which compress and holds together laminated rubber layers. This construction increases the life of the pad, improves the frictional engagement of the pad with the ground surface and permits the easy replacement of the rubber surface when it has become excessively worn.
In a further aspect of the invention, multiple independent pad assemblies are provided. In one embodiment, one pad assembly is disposed directly below the stabilizer arm and may be replaced separately from the outer assembly or assemblies so that the assembly experiencing the most wear may be replaced independently of the other assembly or assemblies, thus reducing the replacement costs due to pad wear.
In accordance with still a further aspect of the present invention there is provided a stabilizer assembly for an earth moving apparatus that is for improving the stability of the earth moving apparatus by employing an offset arrangement, preferably associated with each of the stabilizer arms of the apparatus.
In accordance with one aspect of this offset arrangement, there is provided an apparatus that comprises at least one stabilizer arm and a stabilizer pad disposed on a lower end of the stabilizer arm for engaging a work surface beneath the stabilizer arm. The stabilizer pad comprises a resilient pad member adapted for engagement with the work surface, a plate under which the resilient pad member is supported and including an attachment piece over the plate. An offset bracket intercouples the stabilizer arm and the attachment piece for displacing the pad member and plate so that the attachment piece is in-board of the stabilizer arm.
In accordance with a further aspect of the present invention the apparatus preferably comprises a pair of stabilizer arms supported vertically for limited vertical movement, and the offset bracket extends horizontally from the bottom of each stabilizer arm to the attachment piece. The attachment piece may include a pivot that enables pivoting between the attachment piece and the offset bracket. In one embodiment the offset bracket may include a flat plate secured to the stabilizer arm, and a rod disposed at an opposed end and for defining part of the pivot. In another embodiment the offset bracket may include a rod welded to the bottom of the stabilizer arm. In still another embodiment the offset bracket may be L-shaped secured at one leg to the bottom of the stabilizer arm, and at the other leg fixedly secured to the plate of the stabilizer pad. The resilient pad member may comprise separately disposed pad assemblies.
In accordance with another feature of the present invention there is provided a latch device for use with a stabilizer pad attached to a stabilizer arm of a vehicle and preventing self-flipping of the stabilizer pad relative to the stabilizer arm. This latch device comprises a latch constructed and arranged to have a pivot that enables limited rotation thereof. The latch is adapted to be disposed on either on the stabilizer arm or the stabilizer pad. The stabilizer pad is considered as having one and other positions or surfaces relating to opposed work surfaces. The latch is adapted for engagement with an abutting surface to hold the latch in an armed condition preventing rotation of the stabilizer pad from one position to the other. The latch is also readily manually operated to disarm the latch to enable the pad to be rotated from one position to the other.
A further aspect of the present invention is directed to a stabilizer pad having an offset construction as it relates to the stabilizer arm. There is provided a stabilizer pad in which the downwardly-directed force exerted on the pad by the stabilizer arm is more centrally located on the pad without substantially increasing the load applied to the pad and thus to the underlying surface, and in which the pad does not extend outwardly away from the center of the earth moving apparatus any farther than pre-existing pads, permitting the earth moving apparatus to be used in exactly the same limited or confined locations as existing earth moving apparatus. This result is achieved by providing a rectangular stabilizer pad which has roughly the same or greater dimensions as the stabilizer pad presently being used but which has been rotated 90xc2x0 so that the long dimension of the pad extends in the front to back direction, instead of from an outside edge towards the center of the apparatus. In this novel apparatus, the vertical stabilizer arm is substantially centered on a long edge of the stabilizer pad instead of a short edge and thus is more centered on the pad. This construction reduces excessive wear along one edge, and more evenly spreads the load over the entire lower surface of the pad.
In another aspect of the invention, the molded rubber surface which is disposed on the underside of the prior art stabilizer pad and which is in engagement with the ground surface, is replaced with a removable pad assembly which is comprised of a laminated layers of rubber. The orientation of the rubber layers is vertical or perpendicular to the ground surface. The orientation of the layers may be either parallel to the front to back direction of the earth moving equipment or transverse thereof, depending upon the use of the equipment or wear characteristics desired. The pad assembly includes a bracket and pins which are mounted onto the underside of the stabilizer pad and which compress and holds together laminated rubber layers. This construction increases the life of the pad, improves the frictional engagement of the pad with the ground surface and permits the easy replacement of the rubber surface when it has become excessively worn.
In a further aspect of the invention, multiple independent pad assemblies are provided. In one embodiment, one pad assembly is disposed directly below the stabilizer arm and may be replaced separately from the outer assembly or assemblies so that the assembly experiencing the most wear may be replaced independently of the other assembly or assemblies, thus reducing the replacement costs due to pad wear.
In accordance with still a further aspect of the present invention the offset concepts described herein may be applied, not only to vertically disposed stabilizer arms but also to slanted stabilizer arms. Moreover, the offset arrangement may offset the pads either outboard of the stabilizer arms or inboard of the stabilizer arms.


A process for separating p-diethylbenzene from a diethylbenzene isomers mixture by selective adsorption of p-diethylbenzene on a silicalite adsorbent is disclosed in the present invention, wherein a compressed high pressure CO.sub.2 or propane is used as a carrier for carrying a fixed amount of the diethylbenzene isomers mixture to the silicalite adsorbent bed for the selective adsorption, a first stage effluent stream containing a rich meta-diethylbenzene (m-DEB) and/or ortho-diethylbenzene (o-DEB), but having substantially no para-diethylbenzene (p-DEB) is eluted from the adsorbent bed; when p-DEB of the mixture starts to appear in the first stage effluent stream, a much higher pressurized CO.sub.2 or propane used as a desorbent is then fed into the adsorbent bed, and a second stage effluent stream conaining a rich p-DEB, but having substantially no other DEB isomers is thereby eluted from the adsorbent bed. The diethylbenzene isomers procucts contained in the first and second effluent streams, respectively, can be easily separated from CO.sub.2 or propane simply by reducing the pressure thereof, wherein the resulting CO.sub.2 or propane can be re-compressed and recycled.

p-Diethylbenzene (p-DEB) is used as the desorbent in the Parex process (Derosset, et al., Sep. Sci. Technol. 15, 637 (1980)) for the separation of p-Xylene for xylene isomers and as the cross-linking agent in the synthesis of polymeric resins. One of the ways to produce p-DEB is to separate mixed DEB supplied from ethylbenzene alkylation process (Wang, et al., U.S. Pat. No. 4,950,835). Because of the very close boiling points possessed by DEB isomers: for example, ortho-diethylbenzene (o-DEB) is 183.degree. C.; meta-diethylbenzene (m-DEB) is 180.degree.-181.degree. C.; and para-diethylbenzene (p-DEB) is 184.degree. C., it is difficult to have a complete separation by distillation. The cryogenic separation is an alternative, however, it is in general costly.
At present, while several adsorption processes have been developed for separation of diethylbenzene isomers, the selective adsorption process using zeolite as a adsorbent in liquid phase is most commonly used and it is recognized as a most economic one. For example, disclosed in the U.S. Pat. No. 4,051,192 (1977), Neuzil, et al. used about 70 cm.sup.3 of the zeolite X ion-exchanged with barium (Ba) and potassium (K) to recover 90.7% of p-DEB at the temperature 450 K. and the pressure 136 atm, wherein toulene was used as the desorbent; Lu and. Lee, in their article, Ind. Eng. Chem., Res. 26, 2024 (1987), tested several adsorbents and desorbents for separation p-DEB from mixed DEB and found that the CDZ zeolite was the most appropriate one to obtain p-DEB with a purity over 95% in the temperature range from 393-463 K. and in the pressure range from 1.5 to 3.0 atm. wherein o-xylene was used as the desorbent.
Santacesaria, et al. in their article, entitled "Separation of Xylenes on Y Zeolites in the Vapor Phase. 1. Determination of the Adsorption Equilibrium Parameters and of the Kinetic Regime", Ind. Eng. Chem. Processes Des. Dev. 24, 78-83 (1985) reported the separation of xylene isomers under gas phase operation was found to be superior to that under liquid phase operation. The improvement was attributed to higher mass transfer rate in vapor. But for both operations a desorbent is required. Some of C.sub.8 aromatics were the most commonly employed desorbent.
Several methods of separation using desorbent as mentioned above require using aromatic compounds as a desorbent, therefore, a distillation operation is thereby needed in order to separate desorbent from product, which is energy intensive and increased separation cost.
TAN, Chung-Sung, one of the inventors of the present invention, and Tsay, Jeng-Leei, in their article, entitled "Separation of Xylene Isomers on Silicalite in Supercritical and Gaseous Carbon Dioxide" Ind. Eng. Chem. Res., Vol. 29, 502-504 (1990) reported an experimental study of the separation of an equal amount of p- and m-xylenes on silicalite using carbon dioxide as the carrier and the desorbent. The results showed that the operations in the gaseous phase carbon dioxide offered a better separation efficiency over those at supercritical conditions. The effects of temperature, pressure and flow rate on the effectiveness of separation were also examined. It was found that, for a pulse of 1.0 cm.sup.3 of xylene isomers and 39.5 g of silicalite, the most appropriate operating conditions were a temperature of around 358 K., a pressure of 476 atm and a flow rate of about 15.0 cm.sup.3 /min.
TAN, Chun-Sung, in his U.S. Pat. application Ser. No. 07/801,531 filed on Dec. 2, 1991 (which was allowed on Dec. 24, 1992), disclosed a process for separating ethylbenzene and p-xylene from xylene isomers mixture, wherein a compressed high pressure vapor phase CO.sub.2 was used as the carrier. A fixed amount of xylene isomers was fed into a silicalite adsorbent bed for adsorption operation, and a first stage effluent stream containing a rich m-xylene and/or o-xylene, but having substantially no ethylbenzene and p-xylene was obtained from the adsorbent bed, wherein when ethylbenzene or p-xylene contained in the mixture started to appear in the first stage effluent stream, a supercritical CO.sub.2 used as a desorbent was introduced into the adsorbent bed and a second stage effluent stream containing a rich ethylbenzene and p-xylene, but having substantially no other xylene isomers is thereby obtained. Preferably, the first and the second effluent streams could be separately sent into different activated carbon adsorbent beds to adsorb isothermally and isobarically the said xylene isomers products, and the resulting substantially pure CO.sub.2 exiting from said activated carbon adsorbent bed could be recovered and repeatedly used. Alternatively, the introduction of said high pressure gaseous CO.sub.2 could continue until m-xylene, o-xylene and p-xylene were completely separated from the mixture, and then a supercritical CO.sub.2 was introduced as a desorbent such that a second stage effluent stream containing a rich ethylbenzene (EB) was obtained.
The object of the present invention is to provide a process for separation of diethylbenzene isomers on silicalite in high pressure gaseous CO.sub.2 or propane to produce a high purity of p-diethylbenzene.
Another object of the present invention is to provide a process for separation of diethylbenzene isomers on silicalite in high pressure gaseous CO.sub.2 or propane to to produce a high purity of p-diethylbenzene with a high productivity, that is, the amount of the adsorbent used is relatively lower.
The other object of the present invention is to provide a process for separation of diethylbenzene isomers on silicalite in a high pressure gaseous CO.sub.2 or propane to produce a high purity of p-diethylbenzene, wherein CO.sub.2 or propane is used as a carrier in the first stage of the process and as a desorbent in the second stage of the process, and by reducing the pressure of the effluent stream from the adsorbent bed the diethylbenzene isomers products could be separated from the carrier or desorbent.

Separation of diethylbenzene isomers on silicalite in the presence of high pressure carbon dioxide and propane


As zeolite L is used as catalyst for the chlorination of benzene, chlorobenzene, ortho-dichlorobenzene, and/or meta-dichlorobenzene, its catalytic activity diminishes. Zeolite L which has been used for such chlorinations may be reactivated by contact with steam.

Para-dichlorobenzene is frequently produced by chlorinating benzene and/or chlorobenzene. The formation of para-dichlorobenzene is accompanied by the formation of various by-products such as ortho-dichlorobenzene, meta-dichlorobenzene, more highly chlorinated benzenes, and often some degredation products. In many instances once the desired amount of para-dichlorobenzene (usually, but not necessarily close to the maximum yield attainable) has been produced, the chlorination is terminated in order to conserve chlorinating agent and to maintain the production of undesirable higher chlorinated benzenes at acceptably low levels. It is usually found in these situations that the principal by-product is ortho-dichlorobenzene.
One known way to favor the production of para-dichlorobenzene while reducing the coproduction of the less desired ortho-dichlorobenzene, is to conduct the chlorination in the presence of a catalytic amount of zeolite L catalyst. Such chlorinations are discussed in U.S. Pat. Nos. 4,724,269 and 4,777,305; in European Patent Application Publications No. 0 118 851, 0 154 236, and 0 171 265; and in Huizinga et al, Tetrahedron Letters, Volume 21, pages 3809-3812 (1980), the disclosures of which are, in their entireties, incorporated herein by reference, including especially their descriptions of zeolite L catalysts, the making of such catalysts, and the use of such catalysts in the chlorination of benzene and/or chlorobenzene. U.S. Pat. No. 3,216,789 discloses zeolite L, its preparation and characteristics. D. W. Breck, Zeolite Molecular Sieves, pages 156 and 361, and L. Wilkosz, Przemys Chemiczny, Volume 51, No. 8, pages 524-527 (1972) discuss zeolite L and its characteristics. The disclosures of U.S. Pat. No. 3,216,789 and the cited pages of the Breck and Wilkosz publications are, in their entireties, incorporated herein by reference.
A convenient ratio for characterizing the relative proportions of para-dichlorobenzene and ortho-dichlorobenzene in the organic feedstock, in organic intermediates, and in the organic reaction product is the "para/ortho ratio", often abbreviated as "P/O" or "P/O ratio", which is the ratio obtained by dividing the moles of paradichlorobenzene present by the moles of ortho-dichlorobenzene present. Sometimes the "ortho/para ratio", often abbreviated as "O/P" or as "O/P ratio", which is the inverse of the P/O ratio, is used for characterization purposes.
While the P/O ratio is useful for monitoring relative proportions of para-dichlorobenzene and ortho-dichlorobenzene, it provides little or no information as to how far the chlorination has progressed. A convenient scale of reference which provides this information is the "x-value" which reflects the degree of chlorination of the benzene-based compounds in the organic feedstock, in organic intermediates as the reaction progresses, and in the organic reaction product. The x-value is the value of x in the empirical formula for a mixture of such compounds: C.sub.6 H.sub.6-x Cl.sub.x. It may be calculated as follows: ##EQU1## where A=moles of benzene present:
B=moles of monochlorobenzene present; PA1 C=moles of dichlorobenzene (all isomers) present; PA1 D=moles of trichlorobenzene (all isomers) present; PA1 E=moles of tetrachlorobenzene (all isomers) present; PA1 F=moles of pentachlorobenzene present; and PA1 G=moles of hexachlorobenzene present.
The x-value of the organic reaction product is greater than that of the organic feedstock.
Although zeolite L favors high P/O ratios for organic intermediates and organic reaction products, its effectiveness in this regard declines with continued use. Thus under substantially similar reaction conditions using substantially similar organic feedstocks, the P/O ratio at a given x-value is often lower for later chlorinations than it is for earlier chlorinations using the same zeolite L catalyst. Eventually the catalytic effectiveness of the zeolite L becomes nil.

Process for producing para-dichlorobenzene


A bobbin holding member holds a bobbin, and the bobbin holding member includes a body portion that holds detachably an outer periphery of a brim portion provided to both ends of a middle body section of the bobbin, wherein the body portion includes a fitting portion and a fitting target portion to be fitted to the fitting portion of any of the other bobbin holding members.

The present disclosure relates to a bobbin holding member that holds a bobbin to be used in a sewing machine and a storage case for it.
Conventionally, a bobbin (thread winder) for use in a sewing machine has been generally stored in an accessory storage case of the body of the sewing machine or a tidy. However, a thread wound around the bobbin may have been released and entangled in the storage case or the tidy. Furthermore, when taking out the bobbin and using it, it has been necessary to disentangle the thread or rewind it around the bobbin by hand, resulting in troublesome handling. To solve the problem, for example, a thread winding clip has been proposed which is shaped like a circle having one open end by externally folding back both edges of a plate made of metal etc. The bobbin is arranged to be sandwiched when its body section is pressed into the inner thread winding clip. Then, a plurality of such thread winding clips can be fixed inside the storage case or the tidy with an adhesive agent, to easily store a plurality of the bobbins in a condition where they are set in order. Besides, such a bobbin tidy structure has been proposed that U-shaped cross-sectional bobbin catching strips each of which laterally sandwiches the middle body section of the bobbin may be lined up on the inner bottom surface of the tidy.
However, the thread winding clips described above can be fixed on inside a tidy etc. to store the bobbins in order, and if the thread winding clips are unfixed, they may be scattered in the tidy, thus problematically disabling storing the bobbins in order. Moreover, once the thread winding clips are fixed on inside the tidy etc. with an adhesive agent, they cannot be detached, thereby restricting a space for storing the bobbins in the tidy. It may lead also to such poor usability that accessories (for example, a pair of scissors, various pressers, needles, screwdrivers, etc.) other than the bobbins cannot newly be stored in the tidy. On the other hand, the bobbin tidy described above has bobbin catching strips lined up on its inner bottom surface, so that most of the inner space of the tidy may be occupied by storing the bobbins. This may also has a problem that is similar to that of the aforesaid thread winding clip that the accessories other than the bobbins cannot be stored so much.


Provided are a semiconductor device and a method of fabricating the same. The semiconductor device may include a charge storage structure and a gate. The charge storage structure is formed on a substrate. The gate is formed on the charge storage structure. The gate includes a lower portion formed of silicon and an upper portion formed of metal silicide. The upper portion of the gate has a width greater than that of the lower portion of the gate.

The present disclosure herein relates to a semiconductor device and a method of fabricating the same, and more particularly, to a flash memory device including a charge storage structure and a gate, and a method of fabricating the same.
As the integration degree of a semiconductor memory device is improved, the critical dimension of a gate of a flash memory is gradually reduced. There is a limitation in that the electrical resistance of a gate increases as the critical dimension of the gate decreases. Accordingly, many studies are being conducted to overcome the above limitation.

Semiconductor device and method of fabricating the same

Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do


A device for filling containers, includes a storage container in which a fluid that is to be bottled in the containers can be accommodated, a filling device which fills the fluid into the containers, and a transport line for transporting the fluid from the storage container to the filling device. A valve device is arranged in the transport line between the storage container and the filling device, which valve device automatically switches between an open and a closed state depending on a flow rate of the fluid within the transport line.

DE 103 43 281 A1 discloses a method and a device for producing and bottling oxygen-enriched fluids. This device comprises a filling member with a fluid valve, and also a nitrogen-filled chamber, wherein a through-connection for flushing and/or pre-charging the container with nitrogen can be established between the nitrogen-filled chamber and a container attached to the filling member.
DE 201 20 014 U1 describes a rotary filling machine for filling bottles. This rotary filling machine comprises a rotor which is rotatable about a vertical axis and on which a plurality of filling valves are arranged. The filling valves are connected to a fluid container via fluid lines.
DE 600 06 002 T2 describes a filling head with a flow that can be adjusted by means of a single device. In this case, there is provided in a discharge valve a valve body which is displaceable in the axial direction of the valve. By virtue of this valve body, an adjustable flow quantity reaches a bottling valve, which can function using just one single actuation device.
DE 30 40 880 A1 discloses a container filling member with a return air tube, wherein a permanent fluid barrier is provided in this return air tube. In this case, the return air tube is arranged directly in the filling member and the fluid barrier serves to allow a dry pre-charging for filling the containers.
DE 101 29 155 A1 discloses a filling member for container filling machines. This filling member comprises an outlet for the product, which can be closed by a valve having a valve seat and a movable valve body. The closing movement of this valve body is slowed at least in the end phase by a damping device. Here, too, the valve is arranged directly within the filling member.
Usually the containers to be filled are filled at a certain flow rate or at a maximum flow rate. Under certain circumstances however, for example if the containers that are to be filled break or if the containers exhibit a crack or a non-optimally cooled base after blowing, excessively high flow rates may occur in the filling valve. Due to this excessively high flow rate, considerable pressure shocks occur when the valve is closed, which cause stress on the filling valve and on the components and may even lead to failure of the gaskets.
The object of the present invention is therefore to provide a device for filling containers which prevents overloading of the filling valves at all times. In addition, the intention is also to provide a device which allows a switching of the filling valve during production, without a corresponding annular vessel having to be emptied in order to do this.


A control for varying a maximum transmission power of a transmitter according to a propagation loss or a distance between the transmitter and a receiver is made possible to reduce deterioration of a user capacity to a minimum. In a wave propagation loss measurement section, a calculation is performed on the basis of an amplification factor of a reception amplifier, amplitude information and a base station transmission power information of a reception baseband signal to calculate a wave propagation loss of a reception signal, thereby estimating a propagation loss of transmission signal. The wave propagation loss information is inputted to a maximum amplification amount designation circuit to decide a maximum amplification factor. The maximum amplification amount designation circuit adjusts a maximum transmission power of the transmission signal by designating the decided maximum amplification factor to a transmission amplifier.

1. Field of the Invention
The present invention relates to a CDMA wireless transmission apparatus, a CDMA wireless transmitter-receiver system and transmission power control method of the CDMA wireless transmission apparatus, more specifically to a CDMA wireless transmission apparatus which is possible to determine a maximum value of transmission power of a mobile station and/or a base station according to propagation loss between the base station and the mobile station, a CDMA wireless transmitter-receiver system and transmission power control method of the CDMA wireless transmission apparatus.
2. Description of the Related Art
FIG. 1 shows an example of construction of a mobile communication machine used in the conventional mobile communication system.
In the mobile communication system, a circular small wireless zone (cell) is formed for each base station, the mobile station communicates with the base station in the cell where the mobile station itself is present. A transmitter-receiver of a mobile station 113 is inputted with a radio-frequency signal from a reception antenna 101, which is inputted to a reception wireless section 108. The reception wireless section 108 comprises a reception amplifier 109 and a mixer 110, in which the radio-frequency signal is amplified by the reception amplifier 109 in the reception wireless section 108, and converted to a baseband signal in the mixer 110. The baseband signal is inputted to a reception baseband section 111 and converted into a reception data.
The reception data is inputted in a terminal interface section 107, where it is converted to a user data which can be interpreted by an external terminal such as telephone or video-phone, and then outputted to the external terminal. In a TPC bit analyzer 112, TPC bit inserted in the user data is analyzed. The TPC bit is a transmission power control data instructing the mobile station a transmission power to the communicating station, and the mobile station controls the transmission power according to the instruction. When the TPC bit is "00", the transmission amplifier 103 is controlled to increase the transmission power by +1 dB, or when the TPC bit is "11", the transmission amplifier 103 is controlled to decrease the transmission power by −1 dB.
On the other hand, when a wave is transmitted from the mobile station, the user data inputted from the external terminal is converted into a transmission data by the terminal interface 107, and the transmission data is inputted from the terminal interface 107 to a transmission baseband section 106. In the transmission baseband section 106, the transmission data is converted into a baseband signal and inputted to a transmission wireless section 103. The transmission wireless section 103 is provided with an amplifier 104 and a mixer 105, whereby the baseband signal is converted into a radio-frequency signal by the mixer 105, and, in the amplifier 104, the radio-frequency signal is amplified according to an instruction value from a TPC bit analyzer 112. Then, the radio-frequency signal is inputted from the transmission wireless section 103 to the transmission antenna 102, and a radiowave is transmitted from the transmission antenna 102.
FIG. 2 is a diagram showing an example of construction of a base station used in the conventional mobile communication system.
The signal transmitted from the antenna 102 of the mobile station 113 is inputted to the reception antenna 401 of a base station 413, and then to a reception wireless section 408. In the reception wireless section 408, the received radio-frequency signal is amplified by an amplifier 409, and converted into a baseband signal by a mixer 410. The baseband signal is inputted to a reception baseband section 411, converted into a reception data, and the converted reception data is outputted to a network through an interface 407. In a reception quality measurement section 416, reception quality is measured on the basis of information from the reception baseband section 411, and the reception quality is inputted to a TPC bit inserter 412.
When the user data Is inputted from the network, it is converted into a transmission data in the interface 407, and inputted to the TPC bit inserter 412. In the TPC bit inserter 412, when the reception quality is higher than a reference, TPC bit "11" is added, and when the quality is lower than the reference, "00" is added to the user data. The TPC bit insertion is performed at every 0.667 ms. The user data inserted with the TPC bit is inputted to the transmission baseband section 406 to be converted into a baseband signal. The baseband signal is inputted to the transmission wireless section 403. In the transmission wireless section 403, the base band signal is converted into a radio-frequency signal by the mixer 405, and the radio-frequency signal is amplified by the amplifier 404. The radio-frequency signal is inputted from the transmission wireless section 403 to the transmission antenna 402, and a wave is transmitted from the transmission antenna 402.
In the case of communication by such CDMA wireless access system, all the mobile transmission channels present in the same area use the same frequency to make communication. Therefore, when the transmission power of the transmitter is assumed as a constant value, the reception quality differs due to differences of wave propagation environment.
For example, a case is supposed in which a first mobile station and a second mobile station make communication simultaneously with the same base station. Then, wave propagation loss between the first mobile station and the base station is assumed as 60 [dB], and wave propagation loss between the second mobile station and the base station as 90 [dB]. Transmission power of the two mobile stations is +30 [dBm], reception power at the base station is +30 [dBm] for the first mobile station, and 60 [dBm] for the second mobile station. Compared to the reception power from the second mobile station, reception power from the first mobile station is higher by +30 [dB]. Therefore, since the signal from the first mobile station becomes an interference, signal from the second mobile station cannot be received.
Then, in order to avoid signal reception difficulty due to signal interference and maintain the same reception quality of all users, in the CDMA system, a technique has been known from the past to perform a closed loop high-speed transmission power control. In the high-speed transmission power control, at the base station, reception signal power to interference power ratio of reception signal is measured and compared with a reference value, and according to the comparison result, a TPC bit pattern for controlling the transmission power at the mobile station is determined.
In the high-speed transmission power control, according to communication rate, transmission power control width, and its maximum value and minimum value are determined at fixed values for all wireless channels.
However, adoption of the method in which the maximum value and minimum value of transmission power are fixed values in the conventional high-speed transmission power control has the following problems. That is, when an error occurs in signal reception for some reason, when operation of the transmitter-receiver itself becomes unstable, or when the user capacity that can be contained in the base station reaches a limit, there is the possibility that the mobile station transmits the maximum transmission power regardless of the extent of downward propagation loss. As a result thereof, there is a problem in that a deterioration occurs in the number of users that can be contained by the base station, that is, the user capacity.

CDMA wireless transmission apparatus, CDMA wireless transmitter-receiver system and transmission power control method of the CDMA wireless transmission apparatus


The subject invention relates in part to the control of AAD-1 monocot volunteers in fields planted with dicot crops such as soybeans or cotton. According to some embodiments of the subject invention, cyclohexanedione herbicides are selected as being an effective tool for controlling AAD-1 volunteers, as AAD genes do not impart tolerance to this class of graminicide chemistry. In addition, imidazolinone-class herbicides can be used in some preferred embodiments for selective control of conventional or herbicide-tolerant varieties of volunteer corn. AAD-1 corn comprising Event DAS-40278-9 is used in some particularly preferred embodiments.

Corn (monocot) and soybeans (dicot), for example, can be rotated in various crop rotation cycles in various geographies. Cotton is also a dicot.
"Volunteer" plants are unwanted plants from the prior growing season that emerge in a field planted with crops for the current growing season. Volunteers are basically weeds, and can, like weeds, reduce harvest and yield of the crop of interest for the current growing season. The volunteers divert fertilizer resources and the like from the desired crops.
Unlike plain weeds, volunteers are often specifically engineered to be resistant to some herbicides. Thus, controlling volunteers can be more difficult than controlling naturally occurring weeds.
AAD (aryloxy alkanoate dioxygenase) genes as described herein impart high levels of tolerance to 2,4-D herbicides in plants that are transformed with an AAD gene.
AAD-1 genes (encoding SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3, for example, of the attached sequence listing; see WO 2005 107437) also impart high levels of tolerance to phenoxy- and aryloxyphenoxyproplonate herbicides ("fops" such as fluazifop and haloxyfop) to corn and other monocot species transformed with the gene. (Fops are primarily used to control monocots, as dicots tend to have some natural resistance to fops.) Thus, AAD-1 allows the use of some fops as either selection agents or as herbicides on crops where crop destruction would be expected without the AAD-1 gene.
AAD-12 and AAD-13 genes also impart high levels of tolerance to pyridyloxyacetate herbicides (such as triclopyr and fluroxypyr; "pyrs"). Thus, AAD-12 and AAD-13 each allow the use of pyrs as either selection agents or as herbicides on crops where crop destruction would be expected without the AAD-12 or AAD-13 gene.
There are very numerous types of monocot- or grass-only herbicides (that kill monocots).
ACCase inhibitor herbicides include fops and dims.

This patent is subject to a terminal disclaimer.

Control of AAD-1 monocot volunteers in fields of dicot crops


In a circuit for expanding and/or compressing an amplitude of an input signal; a control signal is generated in response to the input signal and supplied to a multiplier circuit for multiplying the input signal by the control signal, a first subtracter subtracts the input signal from the output of the multiplier circuit, a signal processor processes the first subtracter output signal, and a second subtracter subtracts the output signal of the processor from the output signal of the multiplier circuit. The control signal generating circuit includes an envelope detector for detecting the envelope of the output signal of a proceeding absolute value generating circuit and which includes a pre-bit-shifting circuit for bit-shifting the envelope detected output signal by an amount determined by a pre-bit-shifting control signal, a normalizing circuit bit-shifting the output signal of the pre-bit shifting circuit so such that a normalized output signal is generated, the normalizing circuit further generating a bit shift signal representing a bit shift amount required for normalizing a pre-bit shifted signal corresponding to the detected envelope output signal occurring just prior to the current detected envelope output signal being applied to the pre-bit-shifting circuit, and a control circuit supplied with the bit shift signal for generating the control signal supplied to the pre-bit-shifting circuit.

1. Field of the Invention
The present invention relates to an amplitude compressing/expanding circuit which is suitable for use in signal processing circuits of electronic appliances such as a compact disc (CD) player or a tape recorder.
2. Prior Art
In digital audio signal reproducing apparatus such as CD players and digital audio tape recorders (DAT), an audio signal is digitized and recorded on a recording medium, then reproduced and demodulated into a corresponding analog signal, whereby, a high-quality audio signal with little noise over a wide dynamic range is obtained.
An audio signal obtained from such digital audio signal reproducing apparatus, however, has an undesirably wide dynamic range.
Because of the unnecessarily wide dynamic range, the signal waveform of this audio signal, when recorded by an analog tape recorder, is distorted at its higher signal level portion or has a deteriorated SN (signal-to-noise) ratio at its lower signal level portion.
Further, when a CD player or the like plays back such a signal in an environment where there is background noise, such as within an automobile, there arises another problem in which the signal portion at the lower signal level is lost in the background noise and becomes inaudible, or, conversely, the signal portion at the higher signal level produces an excessively large volume of sound.
To solve such conventional problems, one of the better solutions is to reduce the dynamic range of the audio signal obtained from the digital audio signal reproducing apparatus.
As shown in FIG. 1 for an input signal derived from an audio signal converted into an analog signal, the input signal at levels lower than -30 dB of the peak level is transformed to an output signal having a signal level which varies in proportion to the variation in the input signal level, the constant of proportion being 1.
For the range higher than -30 dB, the input signal also may be transformed to an output signal having a signal level which varies in proportion to the variation in the input signal level, with, however, a constant of proportion, for example, of 1/2.
By so doing, an input-output characteristic having ratios of amplitude compression (CR) of 1 at levels below the -30 db point and 2 at levels above the -30 db point is obtained (hereinafter such point, -30 db in the example, will be referred to as a threshold point, or level). As a result the dynamic range of the audio signal as a whole can be made narrower.
A prior art method using an amplitude compressing/expanding circuit 1 of the structure shown in FIG. 2 achieves such an amplitude compressing and expanding effect.
An input signal S.sub.I is input to an amplitude modulation circuit 3 through a delay circuit 2 and to a control signal generator circuit 4.
The control signal generator circuit 4 detects the signal level of the input signal and, based upon the result of the detection, outputs to the amplitude modulation circuit 3 a control signal S.sub.G having a signal level which changes in accordance with the signal level of the input signal S.sub.I.
The amplitude modulation circuit 3 is constructed of a multiplier circuit, such as a VCA (voltage controlled amplifier) or the like. By having the input signal S.sub.I amplitude-modulated by the control signal S.sub.G, an output S.sub.O is obtained having a signal level corresponding to the input signal S.sub.I, but changed according to the signal level of the control signal S.sub.G.
The delay circuit 2 is provided so that no overshoot may occur in the output signal S.sub.O.
Representing the amplitude of the input signal S.sub.I by "x" and the amplitude of the output signal So by "y", y can be expressed as a function of x and the amplitude compression ratio CR: EQU y=x.sup.1/CR ... (1)
For an amplitude compression ratio CR of 1 as when below the threshold point, the amplitude y is expressed as: ##EQU1##
The amplitude compression ratio CR of value 1 in the region below the threshold point can be obtained by generating control signal S.sub.G so that the gain "g" in the amplitude modulation circuit 3 equals 1, as expressed by EQU g=1. (3)
In contrast thereto, to obtain an amplitude compression ratio CR of value 2 as desired for when applied to the amplitude x of the input signal S.sub.I in the range above the threshold point, the amplitude "y" of the output signal S.sub.O and the gain "g" in the amplitude modulation circuit 3 are given by ##EQU2##
Therefore, an input/output characteristic providing the amplitude compression ratio CR having value of 2 for the range above the threshold point can be obtained by outputting the control signal S.sub.G so that the gain g in the amplitude modulation circuit 3 may become x.sup.-178 .
To provide such a characteristic, the control signal generator circuit 4 may be structured, for example, as shown in FIG. 3. As illustrated the input signal S.sub.I is supplied through an absolute value circuit 5 to an envelope detector circuit 6 to produce a detection signal S.sub.L proportional to the signal level of the input signal S.sub.I. This signal is then subjected to logarithmic conversion in an logarithmic converter circuit 7 and output to an adder circuit 9.
The adder circuit 9 sums the logarithmically-converted detection signal S.sub.L and a threshold point signal S.sub.H. A clipping circuit 8 receives the output of the adder circuit 9 and clips the summation signal below a 0 value and outputs the clipped signal S.sub.CL to a multiplier circuit 10.
Thus, because the input signal S.sub.I is determined by the threshold point signal S.sub.H, a clipped signal S.sub.CL is obtained which varies with respect to the input signal S.sub.I by setting the threshold point signal S.sub.H to a predetermined value.
The multiplier circuit 10 receives both the clipped signal S.sub.CL and a compression ratio controlling signal Sp and outputs a product signal thereof to the amplitude modulation circuit 3 through an exponential converter circuit 11.
By expressing the amplitude of the input signal S.sub.I at the threshold point (-30 dB in the present case) as "Y" and the amplitude of the output signal from the logarithmic converter circuit 7 as H when the input signal S.sub.I is at its peak level, the threshold point signal S.sub.H is expressed as EQU S.sub.H= H-Y/20 log.sub.e 10 .... (6)
Accordingly, a clipped signal S.sub.CL is obtained having a signal level which varies with the signal level of the input signal S.sub.I only when the input signal S.sub.I is larger than the signal level at the threshold point.
As a result, in the range below the threshold point, the clipped signal S.sub.CL clipped at the 0 value through the clipper circuit 8 is obtained, and a control signal S.sub.G is output through the exponential converter circuit 11 having a value of 1 corresponding to the 0 value.
Consequently, the gain of the multiplier circuit 3 is limited to 1 and an output signal S.sub.O is obtained having an amplitude compression ratio CR equal to 1 as shown in equation (2). Thus, the input/output characteristic for producing an amplitude compression ratio CR of 1 is obtained.
For the range above the threshold point, the input/output characteristic for producing an amplitude compression ratio of 2 will be satisfied if the gain of the multiplier circuit 3 is arranged to become h.sup.-1/2, as indicated in equation (5).
To do so a control signal S.sub.G, expressed as EQU S.sub.G =x.sup.(1-CR)/CR .... (7)
may be output with respect to the input signal S.sub.I.
More particularly, if the compression ratio controlling signal Sp is supplied to the multiplier circuit 10 so that the gain therein is expressed as EQU Ap=-(CR-1)/CR=-1/2 .... (8)
an output signal S.sub.O can be obtained whose amplitude is compressed by the compression ratio CR (CR=2 in the present case) in the range above the threshold point.
Thus, an amplitude compressing/expanding circuit 1 can generate an input/output characteristic which changes the amplitude compression ratio CR from 1 to 2 when the signal level of the input signal S.sub.I is increased across the signal level at -30 db.
However, in the above-described conventional circuit arrangement, the amplitude compression ratio CR abruptly changes between the front range and the rear range of the threshold point, and therefore, when the audio signal is reproduced in the conventional amplitude compressing/expanding circuit I, the reproduced sound is extremely unnatural to listeners.
To solve such problem, one conventional method has been proposed in which the amplitude compression ratio CR is gently changed by gradually changing the signal levels of the threshold point signal S.sub.H and the compression ratio controlling signal Sp in accordance with a change in the signal level of the input signal by using, for example, a ROM (read only memory) table.
Another conventional method has been proposed in which the threshold point signal S.sub.H and the compression ratio controlling signal Sp are controlled by a control circuit having a processing circuit arrangement instead of ROM table.
However, if such conventional methods are used, the construction of the amplitude compressing/expanding circuit as a whole becomes complex. Therefore, such methods are not yet satisfactorily practicable in the recent technology.
Further, because the output signal S.sub.O of the above-described amplitude compressing/expanding circuit is only obtained as a multiplied output signal S.sub.O depending upon the control signal S.sub.G provided from the control signal generator circuit 4, the operating characteristic cannot be variable in accordance with the frequencies of the input signal.
The capability of making the operating characteristic of an amplitude compressing/expanding function variable with the frequencies of the input signal is widely applicable to the arts for handling audio signals. For example, the input signal is applied to the compressed amplitude audio signal to compensate for the lack of the dynamic range that can be heard.

Amplitude compressing and/or expanding circuit employing enhanced normalization


An electrode for interventional purposes, such as a cardiac pacemaker, neurostimulation, or ICD electrode, comprises an elongate electrode body (6), at least one electrode pole (5) in the area of the distal end (4) of the electrode body (6) for delivering an intervention pulse, at least one supply line (7) running in the electrode body (6) to the at least one electrode pole (5), and an electrode sheath (8) for insulating the supply line (7). The first and/or second material is produced in such a way that it contains conductive particles embedded in a polymer matrix in a concentration which is greater than or equal to the percolation threshold.

1. Field of the Invention
The present invention relates to an electrode for interventional purposes, such as a pacemaker or ICD electrode or an electrophysiological catheter, as is used, for example, with pacemakers, defibrillators, neurostimulators, and in procedures of electrophysiology (EP).
2. Description of the Related Art
Electrodes of this type are known to have an elongate electrode body having a distal end and a proximal end. At least one active electrode pole for delivering an intervention pulse is provided in the area of the distal end. This electrode pole is designed, for example, as a tip electrode pole situated directly at the distal end, as a ring pole placed at a distance therefrom, or as a shock electrode. The intervention pulses delivered via this pole are, for example, the pacemaker pulses of a cardiac pacemaker and/or neurostimulator, a high-voltage pulse in the case of a defibrillator, or an ablation energy pulse in the case of an ablation device.
A supply line comprising a first material, which produces a connection to this electrode pole, runs in the electrode body. Furthermore, such electrodes for interventional purposes usually have further electrode poles to thus be referred to, using which the electrode may come into contact with tissue. A ring electrode pole of a bipolar electrode or an EP catheter are cited as examples. Furthermore, an electrode sheath which encloses the at least one supply line is provided in the electrode body, which comprises a second material. This material is usually insulating and/or different from the first material.
In recent years, magnetic resonance (MR) diagnostic devices, also referred to in the following as MR devices (such as magnetic resonance tomographs=MRT) have gained great significance because of their examination methods, which are protective of patients, noninvasive, and completely free of pain and side effects. Typical electrodes for interventional purposes display the problem that electrodes of this type heat up strongly in magnetic resonance diagnostic devices under the influence of the electromagnetic radiation thus generated because of electromagnetic induction and the discharge of the induced energy in the area of their contact surface(s) to the tissue. The reason for this is particularly the solid, metallic supply lines to the electrode poles, which act as an antenna and in which, because of their insulation, the antenna currents induced by high frequency (HF) fields may only be discharged into the body electrolytes at the electrode poles, which form the electrical interface to the tissue. The cited HF fields operate, for example, in an operating frequency range of 21 MHz in a 0.5 Tesla MR tomograph. The operating frequency range may extend up to 300 MHz in 7 Tesla MR tomographs according to the current prior art and is typically at 64 MHz in a 1.5 Tesla MR tomograph, for example. Because extremely strong heating in the tissue may occur in proximity to the electrode pole, access to magnetic resonance diagnostic devices is typically blocked to wearers of cardiological and neurological intervention devices, such as cardiac pacemakers, neurostimulators, or defibrillators.
To prevent and/or minimize the hazardous heating of the body cells, the maximum antenna current must be limited and/or reduced. Known solutions suggest discrete components for this purpose, which act as a band-stop filter or as a low-pass filter and thus limit the conduction resistance of the antenna for the frequencies of interest. Other solutions suggest capacitors, which are connected in parallel to the insulation and thus dissipate the antenna current.
In this regard, for example, U.S. Pat. No. 6,944,489, US 2003/0144720 A1, US 2003/0144721 A1, US 2005/0288751 A1 (and the simultaneously published parallel publications US 2005/0288752 A1, US 2005/0288754 A1, and US 2005/0288756 A1, which have essentially the same wording) are cited.
In principle, this possibility exists, of influencing the inductance and capacitive coupling of the antenna by construction measures and thus reducing the flow of the antenna current, dissipating it, or shifting the resonance frequency. The construction requirements placed on the electrode from a therapeutic aspect only allow little play for this purpose, however.
Furthermore, in contrast to the very simplified consideration used here, antennas also have further resonance frequencies, so that the shift of the resonance behavior of their electrode may possibly again meet the resonance condition in an MR device using other HF frequencies. This path is therefore not advantageous.
Furthermore, EP 0 884 024 B1 is to be cited as technological background, in which a capacitor is connected between the supply lines for the ablation pole of an ablation catheter and a measuring pole, also situated thereon, for recording ECG signals. Because of this capacitor, high-frequency energy may be delivered for ablation via the ablation electrode and ECG signals may also be recorded simultaneously.
US 2006/0009819 A1 discloses a cardiac pacemaker having an elongate electrode which is connected to a pulse generator connector. A passive lossy circuit is provided, which is electrically connected between a distal section of the electrode supply line and a high-frequency grounded surface. The passive lossy circuit has a high-frequency impedance which is approximately equal to a characteristic impedance of the electrode in its implanted state in the body. The reflection of incident waves is thus minimized at the terminals of the lossy circuit and their energy is intentionally dissipated here. The passive lossy circuit also acts as a low-pass filter, because of which the electrode is functional in normal operation of the cardiac pacemaker.
A further example of such an electrode is described in US 2006/0200218 A1. A solution is suggested therein, in which the electrode sheath at least sectionally comprises frequency-dependent insulating material having a lesser conductivity at lower frequencies, while the at least one supply line is produced in a known way and comprises typical material. The frequency dependence of the electrode sheath is implemented by a polymer composite which has dielectric properties. A capacitive coupling of the electrode supply line to the external medium is thus possible. However, this capacitive coupling leaves high effectiveness to be desired. This is because the resistive frequency-independent component of such a capacitive coupling is constant, because of which the total impedance upon HF incidence of an electromagnetic wave may not assume arbitrarily small values.

Electrode catheter for interventional use