A tube fitting that uses only two components, namely a fitting body and a fitting nut. The nut and body are adapted to be threadably coupled together by relative rotation therebetween. The nut includes an integral tube gripping ring that cooperates with a camming surface on the body when the fitting is made-up. The camming surface preferably has a steep camming angle. The ring is radially compressed against the tube outer wall to form a seal and a tight tube grip. The ring also forms a line contact-type seal against the camming surface. The ring is designed to have a hinging action and to plastically deform during pull-up to embed into the tubing for excellent tube grip, and an axially adjacent swage or collet zone that isolates any stress riser resulting from the embedding action from vibration effects. The fitting components, and particularly the ring, may be case hardened, the fitting may include a self-gauging feature to indicate sufficient pull-up to prevent excessive pull-up. Also provided is a single ferrule tube fitting that uses a steep camming surface and is at least about 3.3 times harder than the stainless steel tube end.

Tube fittings are used to join or connect a tube end to another member, whether that other member be another tube end such as through T-fittings and elbow fittings, for example, or a device that needs to be in fluid communication with the tube end, such as for example, a valve. As used herein the terms "tube" and "tubing" are intended to include but not be limited to pipe as well. Any tube fitting must accomplish two important functions within the pressure, temperature and vibration criteria that the tube fitting is designed to meet. First, the tube fitting must grip the tube end so as to prevent loss of seal or tube blow out. Secondly, the tube fitting must maintain a primary seal against leakage. The requirement that a tube fitting accomplish these two functions has been the driving factor in tube fitting design for decades. A multitude of factors influence the design of a tube fitting to meet a desired grip and seal performance criteria, but basic to any tube fitting design will be: 1) the characteristics of the tubing that the fitting must work with, including the material, outside diameter and wall thickness; and 2) the tube grip and seal performance level required of the tube fitting for its intended applications. The goal is to design a tube fitting that reliably achieves the desired tube grip and seal functions within whatever cost constraints are imposed on the product by competing designs in the marketplace.
A flareless tube fitting generally refers to a type of tube fitting in which the tube end remains substantially tubular, in contrast to a flared tube fitting in which the tube end is outwardly flared over a fitting component. Flared tube ends are commonly encountered in use with plastic tubing and plastic tube fittings. The present invention is not directed to plastic tubing or tube fittings because such fittings have significantly different challenges and material properties that affect the ability of the fitting to both grip the tube and provide an adequate seal. Operating pressures and temperatures are also typically substantially lower in the plastics art. In other words, with respect to tube grip and seal, whatever works in a plastic tube fitting provides little or no guidance for a non-plastic tube fitting.
Tube fittings that are intended for use with stainless steel tubing, for example, are particularly challenging to design in order to achieve the desired tube grip and seal functions. This arises from the nature of stainless steel which, in terms of typical commercially available tubing material, is a very hard material, usually on the order of up to 200 Vickers. Stainless steel tubing is also used for high pressure applications in which the tubing wall thickness is substantial (referred to in the art as "heavy walled" tubing). Heavy wall tubing is difficult to grip because it is not only hard but it is also not particularly ductile. Low ductility makes it more difficult to deform the tubing plastically so as to achieve a desired tube grip.
Tube fittings for stainless steel tubing typically include an assembly of: 1) a tube gripping device, often in the form of a ferrule or ferrules, or a gripping ring-like structure, and 2) a pull-up mechanism for causing the tube gripping device to be installed on a tube end so as to grip the tube end and provide a seal against leakage. The term "pull-up" simply refers to the operation of tightening the tube fitting assembly so as to complete the assembly of the fitting onto the tube end with the desired tube grip and seal.
Usually a stainless steel tube fitting is first assembled in a "finger tight" condition and then a wrench or other suitable tool is used to tighten or "pull up" the fitting to its final initial and complete assembled condition. In some cases, especially for larger tube sizes, a swaging tool is used to pre-install a ferrule onto the tubing. The pull up mechanism most commonly used is a threaded connection of a female threaded nut component and a male threaded body component, with the tube gripping device being acted upon by these two components as they are threaded and tightened together. The body includes a tube end receiving bore with an angled camming surface at the outer portion of that bore. The most commonly used camming surfaces are frusto-conical such that the term "camming angle" refers to the cone angle of the camming surface relative to the tube end longitudinal axis or outer surface. The tube end is axially inserted into the body bore and extends past the frusto-conical camming surface. The gripping device is slipped onto the tube end and the nut is partially threaded onto the body to the finger tight position such that the tube gripping device captured axially between the camming surface and the nut. The nut typically includes an inward shoulder that drives the tube gripping device into engagement with the angled camming surface on the body as the nut and body components are threadably tightened together. The angled camming surface imparts a radial compression to the tube gripping device, forcing the tube gripping device into a gripping engagement with the tube end. The tube gripping device typically is to form a seal against the outer surface of the tubing and also against the angled camming surface.
The most commonly used tube gripping devices in stainless steel tube fittings today (the most commonly used are ferrule-type tube fittings) achieve tube grip by causing a front or nose portion of the tube gripping device to bite into the tube end outer surface. As used herein, the term "bite" refers to the plastic deformation of the tube gripping device into the outer surface of the tube end so as to plastically deform and indent the tubing with an almost cutting-like action to create a generally radial shoulder or wall at the front end of the tube gripping device. This "bite" thus serves as a strong structural feature to prevent tube blow out at high pressure, particularly for larger diameter tubing such as ½″ and higher.
Over the years there have been numerous tube fitting designs that do not rely on a "bite" type action, but rather merely radially compress the tube gripping device against the tubing outer surface, some with the effect of indenting into the tubing without creating a bite. These designs are not suitable for high pressure stainless steel tube fittings. The most common commercially available stainless steel tube fittings especially for high pressure applications have historically been of two radically distinct designs of the tube gripping device—single ferrule tube fittings and two ferrule tube fittings.
A single ferrule tube fitting, as the name implies, uses a single ferrule to accomplish both the tube grip and seal functions. However, it is becoming increasingly recognized that these two functions are at odds with each other when designing a tube fitting that can meet a desired tube grip and seal performance criteria. This is because the design criteria needed to assure that the tube fitting achieves an adequate tube grip usually works against the ability of the single ferrule to also provide an effective seal. Consequently, although prior art single ferrule fittings can achieve adequate tube grip in some cases, this tube grip performance comes at the expense of having a less effective seal. One result of this situation is that some single ferrule tube fittings have been designed with additional components and techniques to achieve an adequate seal. Less than optimum seal performance is particularly noted in single ferrule fittings that attempt to seal against gas, and especially high pressure gas. Single ferrule tube fittings thus are usually more suited to lower pressure liquid applications such as hydraulics, however, even in such lower pressure applications single ferrule seal performance remains less than desired.
For single ferrule tube fittings, the biting action is usually associated with the single ferrule being designed to bow in a radially outward direction from the tube wall in the central region or mid-portion of the single ferrule body between the front and back ends thereof The front end of the ferrule is driven against the angled camming surface of the body by the nut pushing against the back end of the ferrule. The bowing action helps direct the front end of the single ferrule into the tube end. The bowing action is also used to cause the back end of the ferrule to likewise engage and grip the tube end. This is accomplished usually by provided an angled drive surface on the nut shoulder that engages the back end of the single ferrule so as to radially compress the back end of the ferrule into a gripping action on the tube end. In some single ferrule designs, the back end of the ferrule apparently is intended to bite into the tube end. This back end tube grip is sometimes used with the single ferrule in order to attempt to improve the tube fitting's performance under vibration because the back end grip attempts to isolate down-tube vibration from affecting the front end tube bite.
The use of a back end tube grip actually works against the effort to grip the tube end at the front end of the single ferrule. Ideally, the single ferrule should be completely in three dimensional compression between the nut and the camming surface of the body. Providing a back end grip actually places a counter acting tension to the single ferrule that works against the front end compression being used to provide the tube grip. Additionally, the outward bowing action tends to work against the effort to grip the tube at the front end of the single ferrule because, in order to enable the outward bowing action, the single ferrule requires a lessened mass that is adjacent the tube gripping "bite". The outward bowing action radially displaces ferrule mass central to the ferrule body away from the tube end. Consequently, an outwardly bowed single ferrule fitting could be more susceptible to ferrule collapse, loss of seal and possibly tube blow out at higher pressures.
In order to achieve an adequate tube grip on stainless steel tubing, single ferrule stainless steel tube fittings have historically used a rather shallow camming angle of between ten and twenty degrees. This range of angles is referred to herein as "shallow" only as a term of convenience in that the angle is rather small. The shallow camming angle has been used in single ferrule fittings to obtain a mechanical advantage because the shallow angle provides an axially elongated camming surface against which to slide and radially compress the single ferrule front end to bite into the tube end outer surface. Hard stainless steel tubing material necessitated this elongated sliding camming action in order to be able to get the single ferrule to create an adequate bite for tube grip. Over the years, the single ferrule has been through hardened or case hardened so as to be significantly harder than the stainless steel tubing, however, the shallow camming angle is still used today in such single ferrule fittings to obtain a mechanical advantage from the ferrule sliding along the camming surface to produce the "bite" so as to assure an adequate tube grip. An example of a commercially available single ferrule tube fitting that uses a case hardened ferrule and a shallow camming angle of about twenty degrees is the CPI fitting line available from Parker-Hannifin Corporation. Another example is the EO fitting line available from Ermeto GmbH that uses a through hardened single ferrule and a twelve degree camming angle.
In some single ferrule designs, a non-conical camming surface has been tried whereby an attempt is made to simply press the ferrule against the outer surface of the tube end, thereby not creating a bite. The result in such cases however is a low grip or low pressure only fitting that are not well suited to stainless steel fittings.
The shallow camming angle and elongated camming surface and axial movement needed to achieve an adequate tube grip with a single ferrule fitting, however, compromises the ability of the single ferrule to achieve the seal function, especially in extreme environments and for sealing gas. This is because the front end of the single ferrule attempts to make the seal against the axially elongated camming surface. The radially outward bowing action causes a larger portion of the outer surface of the front end of the single ferrule to come into contact with the camming surface against which it is being driven. The result necessarily is a larger seal surface area between the outer surface of the single ferrule and the camming surface. This enlarged seal area causes an unwanted distribution of the sealing force between the single ferrule and the camming surface, and also creates a larger area for surface imperfections to allow leaks to occur. This is particularly a metal to metal seal issue (as contrasted to non-metal to non-metal seals: for example, in a plastic fitting it is usually desirable to provide an enlarged seal contact area because the more highly ductile plastic material can better form a seal between the two surfaces.)
Because historically the single ferrule fitting has used a shallow camming angle to achieve adequate tube grip, the less than optimum seal function is either tolerated as a recognized limitation on the application of the fitting, or additional features have been designed into the single ferrule fitting, most notably attempts to include one or more elastomeric seals with the single ferrule or with which the single ferrule cooperates to provide a better seal with stainless steel tubing. See, for example, U.S. Pat. Nos. 6,073,976 and 5,351,998. U.S. Pat. No. 6,073,976 illustrates a typical example of a single "ferrule" (called a "cutting ring" in the patent) fitting that attempts to solve the "seal" issue with added elastomeric seal. The U.S. Pat. No. 5,351,998 patent describes the benefits obtained by separating the tube grip and seal functions into two separate components.
A commercially available and highly successful two ferrule fitting used for tubing is commercially available from Swagelok Company, Solon, Ohio and is described in U.S. Pat. Nos. 6,131,963 and 3,103,373 both of which are owned in common by the assignee of the present invention, the entire disclosures of which are fully incorporated herein by reference. In this two ferrule fitting, the tube grip and seal functions also are separately achieved by the use of two ferrules. The forward or front ferrule provides an excellent seal even against gas, and the back or rear ferrule provides an excellent tube grip.
The front ferrule achieves an excellent seal by camming against a shallow camming surface angle such as twenty degrees. This is because the front ferrule does not need to slide excessively on the camming surface in order to achieve a tube grip function. Likewise, the front ferrule is not case hardened because the primary purpose of the front ferrule is to seal and is not to bite into the tube end. Thus the relatively "softer" front ferrule achieves an excellent seal, particularly against gas, even though the body conical camming surface presents a camming angle of about twenty degrees.
The back ferrule achieves the tube grip function in the above noted two ferrule tube fitting. The back ferrule is case hardened to be substantially harder than the tube end. The front end of the back ferrule cams against a frusto-conical camming surface formed in the back end of the front ferrule. The ostensible angle of this camming surface is forty-five degrees, but due to the sliding movement of the front ferrule, the effective camming angle is actually a shallow angle of about fifteen to twenty degrees. Although the effective camming angle for the back ferrule is shallow, the back ferrule is not required to provide a primary seal (although it can form secondary or backup seals). The back ferrule also does not exhibit the undesired bowing action but rather grips the tube end as a function of a radially inward hinging action. As used herein, the term "hinging" refers to a controlled deformation of the ferrule such that a central region or mid-portion of the ferrule body undergoes an inwardly radial compression, as distinctly contrasted to a bowing or radially outward displacement. Thus, the effective shallow camming angle not only does not compromise the fitting seal capability, it actually substantially enhances the overall performance of the tube fitting especially for stainless steel tubing.
By using separate ferrules for each to achieve primarily only one of the key tube fitting functions, the two ferrule tube fitting achieves tremendous tube grip and seal functions. This prior art two ferrule tube fitting thus has enjoyed tremendous commercial success especially in the art of stainless steel tubing in part due to its performance characteristics such as high pressure rating on the order of 15000 psi, wide temperature rating of cryogenic to 1200° F. and in many applications a significant number of remakes (a "remake" refers to the loosening and re-tightening of a fitting after an initial pull-up).
U.S. Pat. No. 3,248,136 illustrates use of a single locking ring as opposed to a ferrule, wherein the locking ring acts against a surface having an angle that appears to be greater than twenty degrees or more, but the ring does not appear to plastically deform into the tubing but rather remains elastic so that the ring is designed to retain its original shape after pull-up, both of which are features that are unsuitable for stainless steel tube fittings of the type considered herein. Japanese utility model publication 44-29659 illustrates a tightening ring that appears to be intended to have a bowing effect and grip the tube at the front and back ends. The fitting does not appear to be applicable to stainless steel tubing as the tube is covered with a resin cover.
Many applications and uses of the described two ferrule tube fitting do not require such high pressure, temperature and remake performance characteristics. The present invention is directed to a new fitting concept that can meet lower performance characteristics without compromising overall fitting integrity and performance. Moreover, the present invention is directed to a new single ferrule tube fitting and variants thereof that can exhibit significantly improved performance over prior art single ferrule tube fittings, particularly for applications that do not require the high end performance characteristics of the above described two ferrule tube fitting.


In a method of injecting fuel into the combustion chambers of an internal combustion engine having a plurality of cylinders, wherein a main injection process and a variable number of secondary injection processes assigned to the main injection process are carried out during one working cycle of a piston, a change of the number of secondary injection processes is initiated initially only for some of the cylinders, while the original number of secondary injection processes is maintained for the other cylinders. Subsequently, the proportion of the cylinders to which the change of the number of secondary injection processes is applied is increased.

The invention relates to a method of injecting fuel into the combustion chambers of an internal combustion engine having a plurality of cylinders by a main injection process and a variable number of secondary injection processes.
It is already known, for example, from EP 1 132 607 A2 to carry out one or more pre-injection processes before the actual main injection process during one working cycle of the piston of an internal combustion engine. EP 1 138 921 A2, EP 1 081 365 A2 or DE 196 32 650 C1 describe further similar methods of injecting fuel.
The division of a fuel injection procedure into at least one pre-injection process and the main injection process achieves a reduction of the combustion chamber pressure gradient and therefore a slower pressure build-up in the combustion chamber. This leads to improved noise behavior of the internal combustion engine and a more accurate operation of the engine.
In this context, in particular in ranges with a low rotational speed, two pre-injection processes per working cycle of the piston are also frequently used, whereas no pre-injection process and merely one main injection process are frequently used in ranges of a high engine speed for reasons of improved performance yield. To this extent, one can speak of a variable number of pre-injection processes per main injection process. As it is also possible to carry out further injection processes of small amounts of fuel after the main fuel injection process, that is to say "post-injection processes", pre-injection and post-injection are summarized by the term "secondary injections".
In the transitional ranges where the change is made from an original number of secondary injection processes per working cycle or per main injection process to a changed number of secondary injection processes, problems frequently occur, however, with regard to the ability to regulate the injection process, as well as the torque and performance output, the exhaust-gas behavior, the rotational speed stability and the noise behavior of the internal combustion engine. In this connection, it is insignificant whether the number of secondary injection processes is increased or reduced during the method.
It is therefore the principal object of the present invention to provide a method for injecting fuel into the combustion chambers of an internal combustion engine, in which the transition between different numbers of secondary injection processes per associated main injection process does not lead to an impairment of the operation of the internal combustion engine, that is, to a method in which such transition proceeds harmoniously.

Method for injecting fuel into a combustion chamber of an internal combustion engine


Provided is a lens barrel assembly and method. The lens barrel assembly including: a lens barrel in which at least one lens is installed; a driving member that moves the lens barrel in the direction of an optical axis; a base at which the driving member is accommodated; a guide member that is formed on the base and guides a movement of the lens barrel; and an elastic unit that connects the base and the lens barrel and includes a plurality of elastic members. The lens barrel assembly can improve image quality of an image processing device by stabilizing the movement of the lens barrel.

1. Field of the Invention
The present invention relates to a lens barrel assembly, and more particularly, to a lens barrel assembly in which a lens barrel is stably moved to improve image quality of an image processing device.
2. Description of the Related Art
In image processing devices, such as digital cameras, or camcorders, a lens is moved along the direction of an optical axis to focus or zoom. The lens is often installed in a lens barrel and moved by a driving means, such as a motor. The lens barrel has a predetermined penetration hole, and a guiding unit disposed to be inserted into the penetration hole guides the lens barrel, thereby allowing the lens barrel to move easily.
Often the lens will vibrate while being moved with a motor which may lower the quality of the obtained image.


A hash processing system and method for reducing the number of clock cycles required to implement the SHA1 and MD5 hash algorithms by using a common hash memory having multiple storage areas each coupled to one of two or more hash channels. The system further provides implicit padding on-the-fly as data is read from the common hash memory. The system shares register and other circuit resources for MD5 and SHA1 hash circuits that are implemented in each hash channel, and uses pipelined, two-channel SHA1 and pipelined, single-channel MD5 hash architectures to reduce the effective time required to implement the SHA1 and MD5 algorithms.

The present invention relates in general to security processing systems and, more specifically, to an apparatus and method for hash processing using multiple hash storage areas for reading and writing data during hash processing.
Hash functions have been widely used in modem cryptography to produce compressed data, message digests, fingerprints, and checksums, among other things. A hash function is a mathematical function that takes a variable-length input string, and converts it to a fixed-length output string. The output string is called a hash value, which typically is smaller than the input string. A "one-way" hash function is a hash function that works in one direction, meaning that it is easy to compute a hash value from an input string, but it is difficult to generate a second input string that hashes to the same value. Bruce Schneier, Applied Cryptography, at 429–59 (1996) includes a detailed discussion of various one-way hash algorithms.
In most modem security applications that implement hashing, the hash algorithms used are the SHA1 algorithm as defined in FIPS PUB 180-1, the MD5 algorithm as defined in RFC 1321, and HMAC-SHA1 and HMAC-MD5 as defined in RFC 2104, all of the foregoing which are incorporated by reference in full herein. These algorithms compute a signature or message digest of a sequence of bytes.
The MD5 and SHA1 hashing algorithms each require a temporary working memory of at least sixteen 32-bit words. The algorithms operate on an input data stream in blocks of 64 bytes. If the input data stream is not a multiple of 64 bytes, such as may occur when processing the last portion of data for a data packet, the algorithms define a procedure for implicit padding.
Typically, the temporary working memory is filled with 64-byte blocks of the input data stream. If the last block of input data for a data packet is less than 64 bytes, then the temporary working memory is filled with implicit padding as defined by the algorithms.
SHA1 Algorithm
As mentioned above, a commonly used, one-way hash algorithm is the "Secure Hash Algorithm," or "SHA1," which was developed by the National Institute of Standards and Technology (NIST) and the National Security Agency (NSA). SHA1 is described in detail in the Federal Information Processing Standards Publication 180-1 (May 11, 1993) (FIPS PUB 180-1), issued by NIST.
The federal government requires SHA1 to be used with their standardized "Digital Signature Algorithm" (DSA), which computes a signature for the message from a message digest. In addition, the federal government requires SHA1 to be used whenever a secure hash algorithm is required for a federal application, and encourages its use by private and commercial organizations. Accordingly, the use of SHA1 has become extremely common for applications that need a one-way hash algorithm.
When an input message of any length <264 bits is input into SHA1, the algorithm produces a 160-bit output called a "message digest." SHA1 sequentially processes message blocks of 512 bits when computing a message digest. If a message is not a multiple of 512 bits, then SHA1 first pads the message to make the message a multiple of 512 bits. The padded message is then processed by SHA1 as n 512-bit blocks, M1, . . . , Mn, where each block is composed of sixteen 32-bit words, L0, L1, . . . , L15.
The message digest computation uses two buffers, each consisting of five 32-bit registers, and a sequence of eighty 32-bit words. The registers of the first 5-word buffer are labeled ha, hb, hc, hd, and he, and the registers of the second 5-word buffer are labeled, h0, h1, h2, h3, h4. The words of the 80-word sequence are derived from the sixteen 32-bit words in the message block, and are labeled W0, W1, . . . , W79. A single word register, TEMP, is also employed.
One "round," t, is performed during each iteration of SHA1, where a round is defined as a calculation that operates on one word, Wt, of the 80-word sequence, referred to as the "input sequence." Accordingly, the processing of each block involves eighty iterations. Because each iteration takes one clock cycle, the processing of each block uses eighty clock cycles.
During the eighty iterations, SHA1 uses a sequence of eighty non-linear functions (NLF), f0, f1, . . . , f79. Each function, ft, 0<=t<=79, operates on three 32-bit words, and produces a 32-bit word as output. SHA1 also uses a sequence of constant words, K0, . . . , K79, during the eighty iterations. ft (X, Y, Z) is defined as follows:
ft(X,Y,Z)=(X AND Y) OR ((NOT X) AND Z) (0<=t<=19)
ft(X,Y,Z)=X XOR Y XOR Z (20<=t<=39)
ft(X,Y,Z)=(X AND Y) OR (X AND Z) OR (Y AND Z) (40<=t<=59)
ft(X,Y,Z)=X XOR Y XOR Z (60<=t<=79).
The algorithm also uses a sequence of constant words, K0, . . . , K79. These constants are the same as the constants used in SHA1. In hex, these are given by:
Kt=5A827999 (0<=t<=19)
Kt=6ED9EBA1 (20<=t<=39)
Kt=8F1BBCDC (40<=t<=59)
Kt=CA62C1D6 (60<=t<=79)
To generate the message digest, first the h0, h1, h2, h3, h4 registers are initialized to a predetermined set of initialization values. Specifically, registers h0, h1, h2, h3, and h4 are initialized to the following values, in hex:
h0=67452301
h1=EFCDAB89
h2=98BADCFE
h3=10325476
h4=C3D2E1F0.
The creation of the message digest then involves the following operations, where each of the blocks, M1, M2, . . . , Mn are processed in order:                1) Divide Mx into sixteen 32-bit words, L0, L1, . . . , L15, where L0 is the left-most word, and Mx is the next message block to be processed.        2) Let register ha=h0, hb=h1, hc=h2, hd=h3, and he=h4        3) For t=0 to 15, let Wt=Lt; and                    For t=16 to 79, let Wt=S1(Wt-3 XOR Wt-8 XOR Wt-14 XOR Wt-16), where SX indicates a left circular shift by X bits.                        4) For t=0 to 79,                    TEMP=S5(ha)+ft(hb,hc,hd)+he+Wt+Kt;            ha=TEMP; hb=ha; hc=S30(hb); hd=hc; he=hd                        5) Let h0=h0+ha; h1=h1+hb; h2=h2+hc; h3=h3+hd, h4=h4+he                    Repeat steps 1–5 for the next block.After processing the last block, Mn, the message digest is the 160-bit string represented by the five words h0, h1, h2, h3, h4.
In many cases, the SHA1 algorithm is performed within an application specific integrated circuit (ASIC), where the operations are performed using hardware-implemented logic gates. A hardware implementation of the SHA1 algorithm requires five registers for the 32-bit digest variables h0,h1,h2,h3,h4, which are initialized at start to constant values. It also uses registers for temporary cycle variables ha,hb,hc,hd,he, which have their initial value loaded from the five registers for h0,h1,h2,h3,h4 respectively. There are 80 rounds of hashing operation which changes the ha,hb,hc,hd,he register values. Finally, after 80 rounds, the h0,h1,h2,h3,h4 variables are incremented by ha,hb,hc,hd,he, respectively. In each round of SHA1 operation, the data is read from and written to the temporary working memory. Typically, in prior implementations, each hash operation over 64 bytes takes 80 clocks for each round of SHA1.
MD5 Algorithm
As mentioned above, a commonly used, one-way hash algorithm is "MD5", where MD stands for "message digest." MD5 was developed by Ron L. Rivest, and described in his paper entitled "The MD5 Message Digest Algorithm," RFC 1321 (April 1992).
When an arbitrarily large input message is input into MD5, the algorithm produces a 128-bit output called a "fingerprint" or "message digest" of the input message. MD5 sequentially processes message blocks of 512 bits when computing a message digest. If a message is not a multiple of 512 bits, then MD5 first pads the message to make the message a multiple of 512 bits. The padded message is then processed by MD5 as n 512-bit blocks, M1, . . . , Mn, where each block is composed of sixteen 32-bit sub-blocks, Wj, 0<=j<=15. The main loop of MD5 processes each 512-bit block one at a time, and continues for as many 512-bit blocks as are in the message. The output of the algorithm is a set of four 32-bit words, which concatenate to form a single 128-bit message digest. A four-word temporary buffer (ha, hb, hc, hd) is used to compute the message digest in four so-called rounds of computation, where each of ha, hb, hc, and hd is a 32-bit register. A four-word digest buffer (h0, h1, h2, h3) is used to accumulate the results from each round, and registers h0, h1, h2, and h3 are initialized to particular values as defined in the MD5 algorithm.
The main loop of MD5 has four "rounds," where each round includes sixteen operations. Accordingly, sixty-four operations, i (0<=i<=63), are performed for each message block.
During each operation, a non-linear function (NLF) is performed on three of four 32-bit variables stored in ha, hb, hc, and hd. Then, the operation adds the NLF output to the fourth variable, a sub-block, Mj, of the message, and a constant word, ti. The operation then performs a left circular shift of a variable number of bits, si, and adds the result to the contents of one of ha, hb, hc or hd. Finally, that sum replaces the contents of one of ha, hb, hc or hd, and the next operation is performed. The NLF used for the operations in each round (i.e., each set of 16 sequential operations) is different from the NLF used in the previous round.
After the fourth round, ha, hb, hc, and hd are added to h0, h1, h2, and h3, respectively, and the main loop repeats for the next message block, until the last block, Mn, has been processed. After processing the last block, the message digest is the 128-bit string represented by the concatenated words stored in h0, h1, h2, and h3.
MD5 can be performed by software, or within an application specific integrated circuit (ASIC), where the operations are performed using hardware-implemented logic gates. During one operation, a non-linear function (NLFi) is applied to three of the variables stored in registers ha, hb, hc, and hd. The three variables input into the NLF are the variables stored in hb, hc, and hd, although the input variables could differ for other rounds. The result is added, by a first full adder, to the contents of register ha. A second full adder adds the output of the first full adder to the appropriate sub-block, Wj, for the round and operation being performed. A third full adder then adds the output of the second full adder to the appropriate constant word, ti, for the round and operation being performed.
A shifter then circularly left shifts the output of the third full adder by the appropriate number of bits, si, for the round and operation being performed. Finally, the contents of register hb is added, by a fourth full adder, to the output of the shifter. The output of the fourth full adder is then added to the contents of register hb, and that sum is placed in register ha, for use during the next operation. The next operation will then use a different message sub-block, Wj, constant word, ti, and number of shifts, si, in the left circular shift operation, as well as a different set of three variables to be operated on by the NLF. In addition, the next operation may (or may not) use a different NLF.
During the four rounds associated with one message block, the logic blocks are cycled through sixty-four times. Further, the total number of cycles through the logic is 64n, where n is the number of 512-bit blocks in the message. Each cycle through the logic corresponds to one clock cycle. The clock frequency is limited by the various delays associated with the gates and other logical components. The logic depth of the operation is rather substantial, because the logic includes computationally complex full adders, among other elements. The cumulative delay associated with this design is long, and consequently the clock frequency must be fairly low.
Now describing the MD5 algorithm in more detail and as mentioned above, the four-word digest buffer (h0, h1, h2, h3) is used to compute the message digest, where each of h0, h1, h2, and h3 is a 32-bit register. These registers are initialized to particular values, which are the same initialization values as are used in the standard MD5 implementation.
As described previously, the main loop of MD5 has four rounds, t (0<=t<=3), where each round includes sixteen operations. Accordingly, sixty-four operations, i (0<=i<=63), are performed for each message block.
During each operation, a non-linear function (NLF) is performed on three of four 32-bit variables stored in ha, hb, hc, and hd. Then, the operation adds the NLF output to the fourth variable, a sub-block, Mj, of the message, and a constant word, ti. The operation then performs a left circular shift of a variable number of bits, si, and adds the result to the contents of one of ha, hb, hc or hd. Finally, that sum replaces the contents of hb. The other registers are updated as ha=hd; hd=hc; hc=hb; and hb=sum.
The NLF used for the operations in each round (i.e., each set of 16 sequential operations) is different from the NLF used in the previous round. Each NLF takes as input three 32-bit words and produces as output one 32-bit word. The four NLFs are defined as follows, and are the same as the NLFs used in the standard MD5 implementation:
F(X,Y,Z)=(X AND Y) OR ((NOT X) AND Z) (for round 1:0<=i<=15)
G(X,Y,Z)=(X AND Z) OR (Y AND (NOT Z)) (for round 2:16<=i<=31)
H(X,Y,Z)=X XOR Y XOR Z (for round 3:32<=i<=47)
I(X,Y,Z)=Y XOR (X OR (NOT Z)) (for round 4:48<=i<=63).
The main loop of the MD5 algorithm is performed as described below. First, the values in the four registers of the buffer (h0, h1, h2, h3) are copied into four 32-bit variables ha, hb, hc, and hd, so that ha=h0, hb=h1, hc=h2, and hd=h3.
Each of the four rounds is then performed by applying the following logic, which is the same logic as is used in the standard MD5 implementation. In the functions below, Wj represents the jth sub-block of the message (0<=j<=15), <<<s represents a left circular shift of s bits, and "+" denotes the addition of words.
Round 1: For i=0 to 15,                FF(ha,hb,hc,hd,Wj,s,ti) denotes the operation        ha=hb+((ha+F(hb,hc,hd)+Wj+ti)<<<s).
Round 2: For i=16 to 31,                GG(ha,hb,hc,hd,Wj,s,ti) denotes the operation        ha=hb+((ha+G(hb,hc,hd)+Wj+ti)<<<s).
Round 3: For i=32 to 47,                HH(ha,hb,hc,hd,Wj,s,ti) denotes the operation        ha=hb+((ha+H(hb,hc,hd)+Wj+ti)<<<s).
Round 4: For i=48 to 63,                II(ha,hb,hc,hd,Wj,s,ti) denotes the operation        ha=hb+((ha+I(hb,hc,hd)+Wj+ti)<<<s).
During each round, the three variables operated upon by the NLF, the message sub-block, Wj, the constant word, ti, and the number of shifts, si, in the left circular shift operation change from operation to operation. For each round and operation, these operations are performed sequentially, where the operations are the 64 operations as described in the standard MD5 implementation.
After Round 4, ha, hb, hc, and hd are added to the then current contents of h0, h1, h2, and h3, respectively. The main loop then repeats for the next message block, until the last block, Mn, has been processed. After processing the last block, the message digest is the 128-bit string represented by the concatenated words stored in h0, h1, h2, and h3.
As mentioned above, the MD5 algorithm requires four 32-bit digest variables h0,h1,h2,h3, which are initialized at start to constant values. It also uses temporary cycle variables ha,hb,hc,hd, which load their initial value from h0,h1,h2,h3 respectively. There are 64 rounds of hashing operation, which changes the ha,hb,hc,hd values during processing. Finally, after 64 rounds, the h0,h1,h2,h3 variables are incremented by ha,hb,hc,hd respectively. In each round of MD5 operation, only read operations are performed on the temporary working memory. Typically, each hash operation over 64 bytes takes 64 clocks for each round of MD5.
Temporary Working Memory Usage
Typically, for each hash operation over 64 bytes, including the SHA1 or MD5 operations described above, the hash blocks are idle while the temporary working memory is filled again with the next 64 bytes of input data. This filling operation may typically take 16 clocks to write 16 words of 32-bit data. These idle cycles reduce the ideal bandwidth of a hash circuit or block. It would be desirable to have a hash block that substantially eliminates this loss of ideal bandwidth. Since the hash operation takes several clock cycles to complete, generally the next 64 bytes of input data stream is accumulated in a buffer to load to the temporary working memory as soon as the hash operation is complete.
In standard IPSec and SSL/TLS applications, both encryption and hashing operations are performed. For shorter data packets, the hashing operations typically require an order of magnitude greater number of clock cycles than the corresponding ciphering operations. If several hash blocks are used for the same ciphering channel, then more buffering and working memory resources are required for the hashing operations because of the use of separate buffers and working memory. It would be desirable to have a hash block that implements two (or more) hash channels for each ciphering channel while reducing the size of the required buffering and working memory resources.
Implicit Padding
As mentioned above, implicit padding is defined for both the SHA1 and MD5 algorithms. Prior hash circuits typically perform this padding after a block of data has been loaded into the temporary working memory. This padding adds additional clock cycles of processing time for each 64-byte block of data to be hashed. It would be desirable to avoid the idle clock cycles required for loading the temporary working memory with padding bytes so that bandwidth through the hash block could be increased.
Need for Improved Hash Processing System
As the desire to compute data increases, communication systems increasingly place more demands on the computation speed of cryptographic algorithms. Thus, there is a need for an improved hash processing system that handles SHA1 and MD5 hash operations in fewer effective clock cycles, that makes improved usage of buffering and working memory resources, and that reduces the time dedicated to performing padding prior to hashing of data.

Apparatus and method for a hash processing system using integrated message digest and secure hash architectures


A process for coating of an intraocular lens to impart tissue compatibility thereto, comprising the steps: a) priming said lens using a solution of a polyamine; b) coating the lens treated in step a) above with a solution of a periodate-oxidized polysaccharide selected from heparin, heparain sulphate, and chondroitin sulphate to stabilize said polyamine by covalent and/or ionical cross-linking; c) coating the lens treated in step b) above with a solution of a polyamine; and d) coating the lens treated according to step c) above with a solution of a periodate-oxidized polysaccharide selected from heparin, heparain sulphate, and chondroitin sulphate in the presence of a cyanoborohydride to convert formed labile Schiff's bases to stable secondary amines.

Any surface of a non-biological origin initiates a sequence of unwanted reactions when brought into contact with living tissue or blood. The most well known reactions are those generated by the blood-contacting materials that activate the platelets and the plasma coagulation system leading the formation of a thrombus. Foreign surfaces in living tissue activate the complement and the mononuclear cellsystems, thereby creating inflammatory reactions.
Although the present invention is based on the use of polysaccharides selected from heparin, heparan sulphate and chondroitin sulphate for the purpose of providing stable, biocompatible coatings on intraocular eye lenses, the following discussion and disclosure will be mainly directed to heparin or heparan sulphate. However, it is important to note that the invention is not restricted to these two polysaccharides.
Inmobilisation of the blood-anticoagulant, heparin, to artificial, blood-contacting materials has proven to be a successful approach for achieving a thromboresistant surface suitable for short term use (days and weeks). In tis procedure, the structure characteristics of the endothelial lining of the vascular wall are mimiced by end-point attachment of heparin to the surface.
The surface, prepared by end-point attachment of heparin to a polyamine has the following properties: 1) it is nonthrombogenic, 2) it does not activate the complement system, 3) it does not activate the mononuclear cell system, 4) it adheres and stabilizes growth factors and 5) in general it adheres cells to a much lower extent than other surfaces.
Examples on other products where biocompatible coatings are desired are eye lenses, breast implants, vascular grafts, hip joints etc. The surface in question is excellent also for blood contacting materials.
There are several publications that have described the antiproliferative effect of heparin and heparan sulphate on a number of different cells (smooth muscle cells, epithelial cells). In other publications the growth factor stabilizing and activating effect of heparin has been described.
It is now generally agreed that low molecular weight heparin (less than about 2500 D) inhibits cell growth, whereas high molecular weight heparin (higher than about 6000 D) stimulates cell growth.


The present invention is intended to reduce a f.theta. correction error by correcting an error of an object scanning speed which is produced because a reflecting point of a laser beam moves on a polygon mirror. In an inventive laser scanner, laser light emitted from a laser oscillator is condensed into a beam by a condenser lens at first. This laser beam is reflected by a polygon mirror rotated by a scanning section and is reflected again to a photoreceptor by a curved reflecting mirror. A curved profile of a reflecting plane of the curved reflecting mirror in the main scanning direction is formed so as to be asymmetrical on right and left bounding about a scanning center point. Thereby, variation of speed for scanning the curved reflecting mirror by the light reflected by the polygon mirror may be canceled by the curved reflecting mirror and a speed for scanning the object may be fixed almost at a predetermined speed.

1. Field of the Invention
The present invention relates to an optical scanning apparatus for one-dimensionally scanning an object by light and more particularly to an optical scanning apparatus for use in a laser bar code reader, a laser printer, a laser facsimile, a laser text reader, a digital copier and the like.
2. Description of Related Art
A laser scanner is an apparatus for scanning an object by laser light. In general, the laser scanner is constructed so as to reflect laser light emitted from a laser oscillator by a scanning mirror which rotates or reciprocates and to one-dimensionally scan the surface of an object by the reflected light. A correcting lens or mirror is provided between a predetermined plane of the object and the scanning mirror in order to irradiate laser light in focus and to scan the object at a predetermined scanning speed. A direction in which the laser light is irradiated is changed and the scanning speed is corrected by causing the reflected light to pass through the correcting lens or by reflecting the reflected laser light again by the mirror. Or, thereby, a focal position is changed.
FIG. 10 is a diagram showing a structure of a typical laser scanner according to a first prior art technology. The laser scanner comprises a laser oscillator 31, a condenser lens 32, a one plane mirror 33, imaging lenses 35, a light receiving element 36 and a return mirror 37. The one-plane mirror 33 is a scanning mirror for deflecting a laser beam so that it scans within a predetermined scanning range. It has a single reflecting plane and is provided with an axis of rotation within the reflecting plane so as to be angularly displaceable. The laser beam emitted from the laser oscillator 31 is condensed by the condenser lens 32 to be reflected in an arbitrary direction by the one plane mirror 33. The reflected laser beam is imaged on a scanning position 34 on a predetermined line segment within the plane by the imaging lens 35 which is a f.theta. lens. The return mirror 37 reflects the laser beam imaged out of the above-mentioned line segment among the laser beams which have passed through the imaging lens 35 so as to guide to the light receiving element 36. The light receiving element 36 is disposed right before the scanning position 34 to detect the position of the laser beam which has passed through the imaging lens 35.
FIG. 11 is a diagram showing a structure of a typical laser scanner according to a second prior art technology. The structure of this laser scanner is the same with the laser scanner shown in FIG. 10, except of that the imaging lens 35 is replaced by a curved reflecting mirror 38. The curved reflecting mirror 38 allows the same effect with that of the imaging lens 35 to be obtained and its reflecting plane is formed by a spherical plane whose radius of curvature in the main scanning direction of the laser beam is fixed. In this laser scanner, the laser beam reflected by the one plane mirror 33 is reflected again by the curved reflecting mirror 38 to image at the scanning position 34. A number of proposals have been made since the past as to the concrete structure of the lenses and mirrors composing the laser scanners shown in FIGS. 10 and 11.
While an object scanning speed which is a speed at which the laser beam scans the surface of the object may be increased by increasing the speed of rotation of the one plane mirror 33 in the laser scanners shown in FIGS. 10 and 11, there is a limit in the increase of the speed of rotation because the faster the speed of the rotation, the more complicated the structure of a mechanism for rotating the one plane mirror 33 becomes and the harder the control of the rotation thereof becomes. Therefore, a polygon mirror having a plurality of reflecting planes is normally used instead of the one-plane mirror in increasing the object scanning speed. When the polygon mirror is used, however, the position of reflecting point in the reflecting plane where the laser beam is reflected changes corresponding to an angle of rotation of the polygon mirror because the center of rotation of the polygon mirror is separated considerably from the reflecting planes. The variation of the position of the reflecting point varies depending on the size of an inscribed circle of the polygon mirror and the larger the inscribed circle, the greater the variation becomes.
FIG. 12 is a diagrammatic view for explaining an angular displacement of the reflecting plane of the polygon mirror and changes of the reflecting point. The polygon mirror 39 is assumed to be rotated in the direction indicated by an arrow A centering on the center of rotation C.
In a first state when the laser beam starts to enter one reflecting plane of the polygon mirror 39, the reflecting plane is positioned so that the laser beam 20 condensed by the condenser lens 32 enters the reflecting plane with an incident angle of 45 degrees or more as indicated by a solid line 39a. In the first state, the laser beam 20 reflects at a reflecting point P1 and is deflected in the direction indicated by an arrow 21.
When the polygon mirror 39 is rotated further from the first state, the reflecting plane is positioned so that the laser beam 20 enters the reflecting plane with an angle of 45 degrees as indicated by a two-dot chain line 39b. In the second state, the laser beam 20 reflects at a reflecting point P2 and is deflected in the direction indicated by an arrow 22. The reflecting point P2 is located on an imaginary axis containing an optical path of the laser beam 20 and behind the reflecting point P1 in the incident direction of the laser beam 20. Therefore, the reflecting point moves from the reflecting point P1 to the reflecting point P2 in the direction indicated by an arrow a1 during when the polygon mirror 39 is rotated so as to put the reflecting plane into the second state from the first state.
When the polygon mirror 39 rotates further from the second state, the reflecting plane is positioned so that the laser beam 20 enters the reflecting plane with an incident angle of less than 45 degrees as indicated by a broken line 39c. The laser beam 20 reflects again at the reflecting point P1 and is deflected in the direction indicated by an arrow 23 in this third state. Therefore, when the polygon mirror 39 rotates so as to put the reflecting plane into the third state from the second state, the reflecting point moves from the reflecting point P2 to the reflecting point P1 in the direction indicated by an arrow a2. When the polygon mirror 39 is rotated so as to put the reflecting plane into the first through third states sequentially, the reflecting point reciprocates on the imaginary axis.
The reflecting point will not move as described above when the axis of rotation of the one plane mirror 33 is made to coincide with the reflecting plane in rotating the one plane mirror 33 because the reflecting point within the reflecting plane is always fixed. Therefore, a range in which the laser beam reflected by the one plane mirror can be deflected is bisected by the laser beam which is reflected by the one plane mirror 33 at 45 degrees. Because the reflecting point moves when the one plane mirror 33 of the laser scanner shown in FIGS. 10 and 11 is replaced by the polygon mirror 39 as described above, the linearity of scan at the scanning position 34 corrected by the imaging lens 35 or the curved reflecting mirror 38 drops considerably as compared to the case of using the one plane mirror 33. Further, thereby, the range in which the laser beam reflected by the polygon mirror 39 can be deflected will not be bisected even if the laser beam which is reflected by the polygon mirror 35 at 45 degrees is set as a boundary.
For instance, in the above-mentioned range, a first range to which the laser beam whose reflecting angle at the polygon mirror 39 is 45 degrees or more is emitted, i.e. a range from the direction indicated by the arrow 21 to the direction indicated by the arrow 22, is narrower than a range to which the laser beam whose reflecting angle at the one plane mirror 33 is 45 degrees or more is emitted. Conversely, a second range to which the laser beam whose reflecting angle at the polygon mirror 39 is 45 degree or less is emitted, i.e. a range from the direction indicated by the arrow 22 to the direction indicated by the arrow 23, is wider than the range to which the laser beam whose reflecting angle at the one plane mirror 33 is 45 degrees or less is emitted.
Accordingly, if the speed of rotation of the reflecting plane of the polygon mirror 39 is equal with the speed of rotation of the reflecting plane of the one plane mirror 33, the speed for scanning the curved reflecting mirror 38 by the laser beam emitted in the first range is slower than the speed for scanning the curved reflecting mirror 38 by the laser beam reflected by the one plane mirror 33, bounding the laser beam whose reflecting angle at the polygon mirror 39 is 45 degrees. Conversely, the speed for scanning the curved reflecting mirror 38 by the laser beam emitted to the second range is faster than the speed for scanning the curved reflecting mirror 38 by the laser beam reflected by the one plane mirror 33. The object scanning speed in scanning the object by reflecting those laser beams by the curved reflecting mirror is proportional to the scanning speed of the curved reflecting mirror 38. From these facts, when the polygon mirror is used as the scanning mirror, the object scanning speed is not kept at a predetermined speed, producing a large error in the scanning speed. Therefore, a f.theta. correction error may increase.
As a prior art technology of this laser scanner, there has been an optical scanning apparatus using an optical scanning curved mirror as disclosed in Japanese Unexamined Patent Publication JP-A 62-253116 (1987). This optical scanning apparatus is constructed so as to deflect light emitted from a light source by a scanning mirror and to reflect this light by an optical scanning curved mirror to condense and image linearly on a photoreceptor drum. A curved profile of this optical scanning curved mirror in the direction orthogonal to a locus on which a reflecting point where the light deflected by the scanning mirror is reflected moves is slanted such that an incident angle of the light increases gradually from the middle part to the both ends in order to deflect the light deflected by the scanning mirror in the direction intersecting with the plane of deflection of the light. Because the curved profile in the direction parallel with the locus in the reflecting planes of the optical scanning curved mirror is nearly parabolic, the radius of curvature thereof is almost fixed. Therefore, it is difficult to prevent the error of the object scanning speed described above.


A bicycle derailleur comprises a base member structured to be mounted to a bicycle frame; a link mechanism having a first portion and a second portion, wherein the first portion of the link mechanism is coupled to the base member, and wherein the second portion of the link mechanism is disposed above the first portion of the link mechanism; and a chain guide coupled to the second portion of the link mechanism so that the chain guide moves relative to the base member to move a chain among a plurality of sprockets.

The present invention is directed to bicycles and, more particularly, to a derailleur used to shift a chain among a plurality of sprockets.
Bicycles are used both for general transportation as well as many recreational activities. Sometimes the bicycle is transported to locations away from home before being ridden. As a result, in recent years bicycles have been developed to make them more compact to facilitate transportation and ease of use, for example, but without losing functionality expected of bicycles. This includes the development of bicycles that have smaller wheels than those found on conventional bicycles.
Many bicycles currently available have multiple speed transmissions that allow the rider to select gear ratios to accommodate changes in running conditions. Such transmissions sometimes include a derailleur for transferring a chain among a plurality of sprockets. For example, a rear derailleur may be detachably fixed to the back end of the bicycle frame, wherein the rear derailleur engages a chain on any one of a plurality of sprockets that are rotatably mounted on the rear wheel hub. One such derailleur is disclosed in Japanese Unexamined Patent Application Number 8-188852. The rear derailleur taught in that publication comprises a base member disposed on a rear end of the bicycle frame, a four-point link mechanism disposed on the base member, and a chain guide disposed on the four-point link mechanism. When this rear derailleur is operated, the four-point link mechanism moves the chain guide laterally onto any one of a plurality of sprockets mounted to the rear wheel axle.
When a conventional derailleur is mounted on a small-wheeled bicycle, there is a risk that the rear derailleur may come into contact with the road surface when the bicycle is inclined either when the bicycle is stopped or during riding. While this does not pose a problem in terms of rear derailleur function, the surface of the rear derailleur may become damaged and the appearance of the rear derailleur suffers.

Bicycle derailleur with a chain guide disposed at an upper portion of a link mechanism


A proton conductor comprises a base material, an acidic substance and a basic substance, wherein the acidic substance has protons; at least part of the protons are dissociated by the basic substance; and at least one of the acidic and basic substances is immobilized on a surface of the base material. At least part of the acidic substance and/or at least part of the basic substance may be a polymer. A powder or a porous body having pores or through-holes can be used as the base material. An organic compound having a hydrophilic part and a hydrophobic part in the molecule can be used as the at least one of the acidic and basic substances.

In recent years, there have been developed polymer electrolyte fuel cells which can be operated in a temperature range of from ordinary temperature to around 80° C. by using as an electrolyte membrane a polymer electrolyte membrane which is a proton conductor. Polymer electrolyte fuel cells have a wide variety of applications such as power generation systems for domestic power supply, distributed power supply and the like, cogeneration systems combining the above power generation systems with waste heat recovery technology, power supply for driving mobile bodies such as automobiles, and power supply for mobile terminals of electronic equipment and the like.
In order to commercialize polymer electrolyte fuel cells, higher output is desired. Increase of the operation temperature of fuel cells, specifically to 100° C. to 200° C., is considered to be effective for this purpose, because increase of operation temperature can increase the efficiency of power generation of the cells and improve the output of the fuel cells.
Polymers typically used as a proton conductor for polymer electrolyte fuel cells at present are fluorocarbon polymers having a strong acid functional group in a side chain, that is, perfluorosulfonic acid polymers. Among them, Nafion® manufactured by EI du Pont de Nemours and Company is the most typical one. Perfluorosulfonic acid polymers have the advantage that, by humidification, they have a very high proton conductivity of around 10−1 S/cm in a temperature range of from ordinary temperature to 100° C.
However, perfluorosulfonic acid polymers have the disadvantage that their proton conductivity is greatly reduced at a temperature of 100° C. or more. Therefore, it is impossible to use them in a high temperature environment. Perfluorosulfonic acid polymers retain water by humidification, and this water forms an ion-conducting path. Proton conductivity is greatly reduced because the water forming the ion-conducting path is evaporated at a temperature of 100° C. or more.
In order to solve the problem as described above, use of a basic polymer doped with a strong acid as a proton conductor is disclosed (for example, refer to Patent Document 1). This proton conductor is a basic polymer such as polybenzimidazole doped with a strong acid in liquid form such as sulfuric acid or phosphoric acid.
Patent Document 1 describes the "doping" as follows. When basic polymers are doped with strong acids, the strong acids are dissociated into protons and acid anions. The basic polymers receive protons dissociated from the acids and are protonated. The protonated basic polymers form acid-base bonding with the acid anions. The thus formed proton conductors exhibit a high proton conductivity of 10−2 S/cm or more in a temperature range of from 100° C. to 200° C. even under low humidity.
However, since the proton conductor described in Patent Document 1 is obtained by "doping" a basic polymer with an acidic substance, the bonding strength between the basic polymer and the acidic substance is not necessarily sufficient. Therefore, there is a problem that the proton conductivity is prone to be reduced due to the elimination of the acidic substance from the proton conductor. It is likely that the performance of the fuel cells using a proton conductor as described above is prone to be reduced (for example, refer to Non-Patent Document 1).
Moreover, there is proposed a proton conductor obtained by impregnating an acidic polymer (or a basic polymer) with a basic polymer (or an acidic polymer) so as to form acid-base bonding (for example, refer to Patent Document 2). It is described that this proton conductor exhibits a proton conductivity of from 10−3 to 10−2 S/cm at 150° C. in a low-humidity condition (in a nitrogen stream). It is likely that the reduction of proton conductivity due to the elimination of acid or base is alleviated since both the acid and base are polymers in the proton conductor described in Patent Document 2.
However, the proton conductor described in Patent Document 2 has a problem that its proton conductivity does not attain a practical level in a temperature range of from 100 to 200° C. This may be due to the fact that, since both the acidic and basic substances are polymers, it is impossible to sufficiently increase the content of the acidic substance or the basic substance in the proton conductor. Generally, the mechanical strength and chemical stability of the polymer containing an acidic or a basic functional group are reduced as the amount of the functional group is increased.
An electrolyte membrane may be prepared from a proton conductor having a low mechanical strength, but problems such as breakage may occur since the strength of the membrane is weak. Further, when chemical stability of a proton conductor is reduced, problems such as elution of polymers at a high temperature or dissolution thereof in water may become conspicuous. Furthermore, there is also a problem that the type of polymers that can maintain heat resistance is limited in a temperature range of from 100 to 200° C.
Moreover, there is also disclosed a proton conductor containing an acidic polymer, a basic polymer and an elastic polymer (for example, refer to Patent Document 3). By incorporating an elastic polymer, it is possible to obtain a proton conductor having an increased mechanical strength compared to a proton conductor consisting only of an acidic polymer and a basic polymer.
However, although the proton conductor described in Patent Document 3 improves mechanical strength, it does not alleviate the reduction of chemical stability. From the viewpoint of maintaining chemical stability, the amount of an acidic substance or a basic substance contained in the proton conductor cannot sufficiently be increased. The result is that the proton conductivity in a temperature range of from 100 to 200° C. also may not attain a sufficiently high level.    [Patent Document 1]: National Publication of International Patent Application No. 1999-503262    [Patent Document 2]: Japanese Patent Laid-Open No. 2001-236973    [Patent Document 3]: National Publication of International Patent Application No. 2003-535940    [Non-Patent Document 1]: Electrochemistry, Vol. 70, No. 12, p. 943-945 (2002)

Proton conductor, electrolyte membrane, electrode and fuel cell


A method for providing an authentication service by using a decentralized identity (DID) application of a first user device, a mobile device, is provided. The method includes steps of: (a) if a signature verification value is transmitted from a service provider server in response to a DID service requested by a second user device, a DID authentication server transmitting the signature verification value to the DID application so that the DID application transmits a user signature and a user DID to the DID authentication server, and (b) verifying the user signature by using a user public key and transmitting signature verification result information to the service provider server, or transmitting the user signature and the user DID to the service provider server, to allow the service provider server to verify the user signature by using the user public key, to thereby provide the DID service to the second user device.

User authentication generally refers to a process of determining whether a user can be trusted by verifying whether the user is legitimately registered in a database of a service provider server. The user authentication plays an important role in managing user access rights for services provided by the service provider server and detecting illegal activities.
Various technologies are used for the user authentication, and some of them include single-factor authentication using a combination of a user ID and a password, two-factor authentication using a combination of two verification means such as a card and a password, a shared key authentication using a secret key shared between involved parties, and biological methods such as fingerprint recognition or iris recognition.
However, since it is a convention for each of multiple service provider servers to store multiple pieces of user information belonging to their own users, risk of user information leakage due to server hacking increases as the number of the service provider servers storing the user information increases.
In addition, the distribution of the user information across the multiple service provider servers makes it difficult for the user to manage his or her history of providing the user information and requires the user to manually amend the user information of each and every service provider server when there is a change to his or her user information. This difficulty of managing one's own user information also gives rise to a potential risk of user ID theft.
Adding to this, the conventional user authentication causes inconveniences of having to memorize both the user ID and the password for each and every service provider server and having to repeatedly input the user information every time the user newly subscribes to the services.
Meanwhile, as an alternative to solve these problems of such centralized user authentication used by the service provider servers, a method of managing the user information by using a blockchain network technology with an improved security and stability is proposed.
A blockchain network uses distributed ledgers to allow multiple participants to jointly manage a series of synchronized ledgers, and this significantly reduces the risk of hacking. Since data on the distributed ledgers is open to all participants, the user information being registered on the distributed ledgers has to be encrypted, for example, by converting the user information to a hash value.
However, even when using the blockchain network, the user is still required to obtain a user ID from each service provider server.
Therefore, an enhanced method for solving the aforementioned problems is required.

Method for providing authentication service by using decentralized identity and server using the same


Some embodiments disclosed herein comprise a method of treating a subterranean formation comprising: providing a treatment fluid comprising a base fluid and an extracted natural mucilage; and introducing the treatment fluid into the subterranean formation. The treatment fluid may further comprise a mucin in an amount in the range of from about 0.000001% to about 10% by weight in the treatment fluid.

The methods of the embodiments described herein relate to treatment fluids for use in subterranean formation operations comprising mucilage compositions.
Subterranean wells (e.g., hydrocarbon producing wells, water producing wells, and the like) are often stimulated by hydraulic fracturing treatments. in hydraulic fracturing treatments, a treatment fluid is pumped into a portion of a subterranean formation at a rate and pressure such that the subterranean formation breaks down and one or more fractures are formed. Typically, particulate solids, such as graded sand, are suspended in a portion of the treatment fluid and then deposited into the fractures. These particulate solids, or "proppant particulates," serve to prop the fracture open (e.g., keep the fracture from fully closing) after the hydraulic pressure is removed. By keeping the fracture from fully closing, the proppant particulates aid in forming conductive paths through which produced fluids, such as hydrocarbons, may flow. Therefore, the ability of the treatment fluid to adequately suspend the proppant particulates with minimal or no settling is important to the success of the stimulation operation.
Well stimulation typically requires large amounts of treatment fluids to be pumped downhole under high pressures and flow rates over short periods of time, causing turbulent flow of the treatment fluid. The turbulence results in friction pressure between the treatment fluid and the stimulation equipment (e.g., wellbore piping, wellbore casing, etc.) and between the treatment fluid and the subterranean formation. The friction pressure increases the energy necessary to pump the treatment fluid downhole and can cause damage to stimulation equipment and the formation at extreme financial costs.
To combat the friction pressure, friction reducers are often added to treatment fluids. Traditional friction reducers are typically polymers (e.g., polyacrylamide, guar gum) that are able to change the rheological properties of the treatment fluid to overcome or minimize friction pressure. Some traditional friction reducing polymers may be characterized by a large hydrodynamic radius such that upon shearing, the friction reducing polymers can absorb energy from high nucleation sites by stretching to a more relaxed form and redistribute the energy to other locales. Other traditional friction reducing polymers may swell to form sticky dispersions or gelatinize so as to suspend turbulent flow.
While traditional friction reducing polymers are effective at reducing friction pressure, enhanced friction reduction is sometimes necessary for particular subterranean formation operations. Moreover, simultaneous enhanced friction reduction and viscosification of the treatment fluid for particulate suspension (e.g., proppant particulates) may be preferred.

Mucilage comprising treatment fluids for subterranean formation operations


A butyl rubber ionomer having improved adhesion to substrates whose surfaces have polar functional groups. Examples of such substrate materials include stainless steel, glass, mylar or Teflon®. The adhesion of the butyl rubber ionomer to the substrate is at least 25% greater than the adhesion of a non-ionomeric butyl rubber to the same substrate surface and with certain substrates is more than 150% greater. The adhesion is improved with increasing levels of multiolefin content in the butyl rubber ionomer. The adhesion is greatest for butyl rubber ionomers having a high multiolefin content (at least 3.5 mol% of multiolefin monomers or at least 1.5 mol % of residual multiolefins). By taking advantage of these high adhesion levels, a composite article can be formed between the butyl rubber ionomer and the substrate.

Poly(isobutylene-co-isoprene), or IIR, is a synthetic elastomer commonly known as butyl rubber which has been prepared since the 1940's through the random cationic copolymerization of isobutylene with small amounts of isoprene (1-2 mole %). As a result of its molecular structure, IIR possesses superior air impermeability, a high loss modulus, oxidative stability and extended fatigue resistance.
Butyl rubber is understood to be a copolymer of an isoolefin and one or more, preferably conjugated, multiolefins as comonomers. Commercial butyl comprise a major portion of isoolefin and a minor amount, not more than 2.5 mol %, of a conjugated multiolefin. Butyl rubber or butyl polymer is generally prepared in a slurry process using methyl chloride as a vehicle and a Friedel-Crafts catalyst as part of the polymerization initiator. This process is further described in U.S. Pat. No. 2,356,128 and Ullmanns Encyclopedia of Industrial Chemistry, volume A 23, 1993, pages 288-295.
Peroxide curable butyl rubber compounds offer several advantages over conventional, sulfur-curing, systems. Typically, these compounds display extremely fast cure rates and the resulting cured articles tend to possess excellent heat resistance. In addition, peroxide-curable formulations are considered to be "clean" in that they do not contain any extractable inorganic impurities (e.g., sulfur). The clean rubber articles can therefore be used, for example, in condenser caps, biomedical devices, pharmaceutical devices (stoppers in medicine-containing vials, plungers in syringes) and possibly in seals for fuel cells.
It is well accepted that polyisobutylene and butyl rubber decompose under the action of organic peroxides. Furthermore, U.S. Pat. Nos. 3,862,265 and 4,749,505 teach us that copolymers of a C4 to C7 isomonoolefin with up to 10 wt. % isoprene or up to 20 wt. % para-alkylstyrene undergo a molecular weight decrease when subjected to high shear mixing. This effect is enhanced in the presence of free radical initiators.
In spite of this, CA 2,418,884 and 2,458,741 describe the preparation of butyl-based, peroxide-curable compounds which have high multiolefin content. Specifically, CA 2,418,884 describes the continuous preparation of IIR with isoprene levels ranging from 3 to 8 mol %. Halogenation of this high multiolefin butyl rubber produces a reactive allylic halide functionality within the elastomer. With these elevated levels of isoprene now available, it is possible, in principle, to generate BIIR analogues which contain allylic bromide functionalities ranging from 3 to 8 mol %. In essence, the relative levels of isoprene and allylic bromide can be tuned within this range. Conventional butyl rubber halogenation processes are described in, for example, Ullmann's Encyclopedia of Industrial Chemistry (Fifth, Completely Revised Edition, Volume A231 Editors Elvers, et al.) and/or "Rubber Technology" (Third Edition) by Maurice Morton, Chapter 10 (Van Nostrand Reinhold Company© 1987), particularly pp. 297-300.
In addition to enabling the co-vulcanization of halobutyl rubber with other general-purpose rubbers, the presence of allylic halide functionalities allows for nucleophilic alkylation reactions. It has been recently shown that treatment of brominated butyl rubber (BIIR) with nitrogen and/or phosphorus based nucleophiles, in the solid state, leads to the generation of IIR-based ionomers with interesting physical and chemical properties (see: Parent, J. S.; Liskova, A.; Whitney, R. A; Resendes, R. Journal of Polymer Science, Part A: Polymer Chemistry 43, 5671-5679, 2005; Parent, J. S.; Liskova, A.; Resendes, R. Polymer 45, 8091-8096, 2004; Parent, J. S.; Penciu, A.; Guillen-Castellanos, S. A.; Liskova, A.; Whitney, R. A. Macromolecules 37, 7477-7483, 2004).
Existing Butyl elastomer grades are used in a variety of applications where the inherent low gas permeation rate is of great importance. The adhesion of butyl rubber to solid surfaces is an important physical property that leads to the formation of composite materials. For example, in multi pane gas filled glass window seals, the low permeation of Butyl elastomers allows the retention of special gases of low thermally conductivity over the life of the window. As the ever-increasing demand for improved energy efficiency drives improvements in window design, better adhesion properties in window seals are required. However, existing butyl rubber polymers exhibit only moderate adhesion to glass surfaces and as a result have deficiencies when used in glass-polymer composite applications. The same is true of metal-polymer and plastic-polymer composite applications.
The publication Bayer—Manual for the Rubber industry 2nd Edition at Page 512 table D10-1 and at page 514 table D10-2 as well as page 515 table D10-4 highlights the poor adhesion of Butyl elastomers to steel, rayon, polyamide and polyester. In thermoset rubber compounds the poor adhesion of Butyl rubber is partially overcome with a laborious process of coating the fabric/steel with a resorcinol, formaldehyde, latex, isocyanate RFL bonding system. In addition a resorcinol, formaldehyde, silica RFS bonding system is incorporated into the thermoset rubber compound. Even with these efforts an adhesion rating of 3, 2, and 0 (0-5 scale, with 5 being excellent) is all that can be expected for rayon, polyamide and regular finish polyester, respectively.
There is therefore a need for improving adhesion between butyl rubber and glass, metal and/or plastic surfaces.
In the past, butyl rubber polymers have exhibited adhesion values of less than 15 psi for stainless steel, less than 10 psi for glass and less than 5 psi for mylar. Improvements in these adhesion values are constantly being sought. To date no attempts have been made to characterize adhesion between butyl rubber ionomers and glass, metal or plastic surfaces.
The need therefore still exists for a butyl polymer having improved surface adhesion characteristics and for composite articles made therefrom.

Butyl ionomer having improved surface adhesion


Two housing members and the stator are precision machined on diameters and assembled such that the machined diameters coact to locate the members which then serve as a reference location for the subsequently assembled parts. The present invention reduces the number of critical machined features compared to a piloted assembly.

In devices such as compressors it is common to have the motor, as well as the pump structure, in a semi-hermetic casing or housing with the motor supported by straddled bearings. The motor structure must be accurately located with respect to the pump structure for proper operation and to avoid undue stress and wear. Conventional assemblies of this type use, for example, locating features such as dowel pins to make the critical alignment of the housing components. This adds critical features to the machining and inspection process. It also increases capital costs for machining and inspection.


A sequencing unit operating along a feed path of a number of opening devices for attachment to respective sealed packages of pourable food products includes a conveyor for conveying the opening devices arranged in at least one line, and a releasable stop mechanism interacting with the opening devices downstream from the conveyor along the path. The stop mechanisms are normally set to a first configuration, in which they arrest the opening devices along the path, and are movable into a second configuration allowing travel of the opening devices. The unit also has a push mechanism traveling at predetermined intervals past the stop mechanism to move the stop mechanism from the first configuration to the second configuration, so that the opening devices are fed in sequence and at a predetermined rate through the stop mechanism.

As is known, many pourable food products, such as fruit juice, UHT (ultra-high-temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.
A typical example of this type of package is the parallelepiped-shaped package for liquid or pourable food products known as TETRA BRIK ASEPTIC (registered trademark), which is made by folding and sealing laminated strip packaging material. The packaging material has a multilayer structure comprising a base layer for stiffness and strength, which may comprise a layer of fibrous material, e.g. paper, or mineral-filled polypropylene material, and which is covered on both sides with layers of thermoplastic material, e.g. polyethylene film. In the case of aseptic packages for long-storage products, such as UHT milk, the packaging material comprises a layer of oxygen-barrier material, e.g. aluminium foil, which is superimposed on a layer of thermoplastic material, and is in turn covered with another layer of thermoplastic material forming the inner face of the package eventually contacting the food product.
As is known, packages of this sort are produced on fully automatic packaging machines, on which a continuous tube is formed from the web-fed packaging material; the web of packaging material is sterilized on the packaging machine, e.g. by applying a chemical sterilizing agent, such as a hydrogen peroxide solution, which, once sterilization is completed, is removed from the surfaces of the packaging material, e.g. evaporated by heating; and the web of packaging material so sterilized is maintained in a closed, sterile environment, and is folded and sealed longitudinally to form a vertical tube.
The tube is filled with the sterilized or sterile-processed food product, and is sealed and subsequently cut along equally spaced cross sections to form pillow packs, which are then folded mechanically to form respective finished, e.g. substantially parallelepiped-shaped, packages.
Alternatively, the packaging material may be cut into blanks, which are formed into packages on forming spindles, and the packages are filled with the food product and sealed. One example of this type of package is the so-called "gable-top" package known by the trade name TETRA REX (registered trademark).
Once formed, the above packages may undergo further processing, such as the application of a reclosable opening devices to protect the food product inside the package from contact with external agents, and to enable the product to be poured out.
At present, the most commonly marketed opening devices comprise an annular frame portion defining a pour opening and fitted about a removable or pierceable portion of a top wall of the package; and a cap hinged or screwed to the frame portion, and which is removable to open the package. Alternatively, other types of opening, e.g. slide-open, devices are also known to be used.
The removable portion of the package may be defined by a sealing sheet glued or heat-sealed to the outside of the package to close a through hole in the package. One example of this solution is described and illustrated in Patent Application EP-A-943549. Alternatively, the removable portion of the package may be defined by a so-called "prelaminated" hole, i.e. a hole formed in the base layer of the packaging material before covering the base layer with other layers defining the packaging material, e.g. the layers of thermoplastic material and/or the layer of barrier material, which close the hole hermetically. One example of this solution is described and illustrated in Patent Application EP-A-331798.
In both cases, the opening devices are fed from a hopper to an adhesive application unit and subsequently to a gluing unit for gluing each opening device to a respective package.
To improve operation of the gluing unit, a need is felt within the industry for a sequencing unit for feeding the opening devices to the gluing unit in sequence and at predetermined travelling speeds and feed rates.
More specifically, a need is felt within the industry for highly flexible sequencing units, i.e. designed to convey the opening devices at different feed rates.
A need is also felt within the industry to reduce the operating noise level of the sequencing unit and at the same time reduce wear of the mechanical components, and so extend the working life, of the sequencing unit.
Finally, a need is also felt within the industry to cut off supply of the opening devices to the gluing unit without stopping the sequencing unit, in the event supply of the respective packages to the gluing unit is temporarily cut off.

Sequencing unit for opening devices for gluing to sealed packages of pourable food products


A fuel supply system of a vehicle is provided with a fuel tank 10 supported on a vehicle at a level equal to or lower than that of the carburetors 16 and 17 combined with an engine 5. A vacuum fuel cut valve 12 is placed on the upper surface of the fuel tank 10. A pulse-driven fuel pump 13 is disposed near the vacuum fuel cut valve 12 on the upper surface of the fuel tank 10. The vacuum fuel cut valve 12 has a fuel inlet port 36 connected to a fuel suction pipe 37, a fuel outlet pipe 28, and a vacuum chamber connected to an intake pipe 21a connected to the cylinder 21 of the engine 5. The pulse-driven fuel pump 13 is provided with a fuel suction pipe 25 connected to the fuel outlet pipe 28 of the vacuum fuel cut valve 12. When a negative pressure pulse is applied to the vacuum fuel cut valve 12, the vacuum fuel cut valve 12 opens to supply fuel to the carburetors 16 and 17.

1. Field of the Invention
The present invention relates to fuel supply system of a vehicle and, more particularly to a fuel supply system of vehicle including a fuel tank disposed at a level not higher than that of a carburetor combined with an engine.
2. Description of the Related Art
In a fuel supply system including a fuel tank disposed at a level higher than that of a carburetor to supply the fuel by the pressure head of the fuel contained in the fuel tank, it is usual to attach the fuel outlet line to the bottom wall of the fuel tank. The fuel outlet line is provided with a fuel cut valve to prevent the fuel contained in the fuel tank from flowing into the carburetor while the engine is stopped.
In a fuel supply system disclosed in Patent document 1 (JP-A 2003-182672) including a fuel tank disposed at a level not higher than that of a carburetor combined with an engine, it is usual to pump up the fuel contained in the fuel tank and to supply the fuel through a fuel supply line to the carburetor by a fuel pump. Since the fuel does not flow naturally from the fuel tank into the carburetor while the vehicle is stationary and the engine is stopped, the fuel supply line of the fuel supply system is not provided with any fuel cut valve.
Even in the fuel supply system including the fuel tank disposed at a level not higher than that of the carburetor, it is possible that the fuel contained in the fuel tank flows into the carburetor if the vehicle is shaken during transportation on a vehicle carrier or if the pressure in the fuel tank rises greatly due to temperature change. If the fuel flows accidentally into the carburetor, the fuel evaporated in the carburetor makes it difficult for the engine to start or the fuel is wasted. The fuel pump of the fuel supply system disclosed in Patent document 1 is disposed apart from the fuel tank. Therefore, it takes a long time for the fuel pump to pump up the fuel from the fuel tank when the engine is started, particularly, when the engine is started for the first time after shipping or after a long interruption of operation and, consequently, it takes a long time to start the engine.


A hermetic scroll-type compressor including a housing, fixed and orbiting scroll members, a frame member having a thrust surface adjacent the orbiting scroll member back surface, and a crankshaft coupled to the orbiting scroll member. A seal between the thrust surface and the back surface of the orbiting scroll member seals between a radially inner portion of the back surface exposed to discharge pressure and a radially outer portion exposed to suction pressure. The frame member defines an annular oil chamber having a side surface and a bottom surface above which the radially outer portion of the back surface orbits in spaced relationship. The oil chamber contains a sufficient depth of oil to extend the oil level above an upper peripheral edge of the orbiting scroll member, whereby oil from the oil chamber is sucked between the intermeshed scroll members. Radial compliance of the orbiting scroll meters the oil flow between the scroll members.

The present invention relates generally to a hermetic scroll-type compressor including intermeshing fixed and orbiting scroll members and, more particularly, to such a compressor having an oil lubrication control mechanism that acts to control the leakage between the orbiting and fixed scroll members during compressor operation.
A typical scroll compressor comprises two facing scroll members, each having an involute wrap, wherein the respective wraps interfit to define a plurality of closed compression pockets. When one of the scroll members is orbited relative to the other, the pockets decrease in volume as they travel between a radially outer suction port and a radially inner discharge port, thereby conveying and compressing the refrigerant fluid.
It is generally believed that the scroll-type compressor could potentially offer quiet, efficient, and low-maintenance operation in a variety of refrigeration system applications. However, several design problems persist that have prevented the scroll compressor from achieving wide market acceptance and commercial success. For instance, during compressor operation, the pressure of compressed refrigerant at the interface between the scroll members tends to force the scroll members axially apart. Axial separation of the scroll members causes the closed pockets to leak at the interface between the wrap tips of one scroll member and the face surface of the opposite scroll member. Such leakage causes reduced compressor operating efficiency and, in extreme cases, can result in an inability of the compressor to operate.
Leakage at the tip-to-face interface between scroll members during compressor operation can also be caused by a tilting and/or wobbling motion of the orbiting scroll member. This tilting motion is the result of overturning moments generated by forces acting on the orbiting scroll at axially spaced locations thereof. Specifically, the drive force imparted by the crank-shaft to the drive hub of the orbiting scroll is spaced axially from forces acting on the scroll wrap due to pressure, inertia, and friction. The overturning moment acting on the orbiting scroll member causes it to orbit in a slightly tilted condition so that the lower surface of the plate portion of the orbiting scroll is inclined upwardly in the direction of the orbiting motion. Wobbling motion of the orbiting scroll may result from the interaction between convex mating surfaces, particularly during the initial run-in period of the compressor. For instance, the mating wrap tip surface of one scroll member and face plate of the other scroll member may exhibit respective convex shapes due to machining variations and/or pressure and heat distortion during compressor operation. This creates a high contact point between the scroll members, about which the orbiting scroll has a tendency to wobble until the parts wear in. The wobbling perturbation occurs on top of the tilted orbiting motion described above.
Further, present scroll compressors of either low side or intermediate designs separate oil out of the compressor before the oil impacts the scroll set (the set of the orbiting and fixed scroll members). Inadequate lubrication of the scrolls permits refrigerant leakage between the scroll wraps and thereby loss of compressor efficiency. Adequate lubrication of the scroll set is necessary during the run-in of the scrolls as well as during normal operation.
Efforts to counteract the separating force applied to the scroll members during compressor operation, and thereby minimize the aforementioned leakage, have resulted in the development of a variety of prior art axial compliance schemes. In a compressor in which the back side of the orbiting scroll member is exposed to suction pressure, it is known to axially preload the scroll members toward each other with a force sufficient to resist the dynamic separating force. However, this approach results in high initial frictional forces between the scroll members and/or bearings when the compressor is at rest, thereby causing difficulty during compressor startup and subsequent increased power consumption. Another approach is to assure close manufacturing tolerances for component parts and have the separating force borne by a thrust bearing or surface. This requires an expensive thrust bearing, and involves high manufacturing costs in maintaining close machining tolerances.
The present invention is directed to overcoming the aforementioned problems associated with scroll-type compressors, wherein it is desired to provide an oil control mechanism that helps to prevent leakage between the interfitting scroll members.