Abstract:
An assembly of the spaced apart cam pins (or longitudinal arms) for a wrench is provided which is radially biased with respect to the workpiece opening and retained by metal spring elements formed in circumferential rings, spaced apart along the length of the arms, and acting upon adjacent arms. These spring rings are protected by intervening retention rings used to secure the assembly into the wrench housing. One or more of the spring rings can be secured to the end face of the arms, by a locking interface with notches in the end faces. A circumferential ring used intermediate the end faces of an arm can use a dimension reduction of the arm cross section in order to secure the arm. Alternatively, using spring rings at each end of the arms, with a shielding retention ring adjacent each spring ring, permits the camming functionality of the assembly to be readily utilized in more conventional wrenches.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to workpiece engaging apparatus, and more particularly to wrenches of various types, including socket wrenches. The present invention is intended to improve upon the invention disclosed in U.S. Pat. No. 7,290,467, entitled a “Socket Wrench Apparatus,” by the same inventor. In addition to providing improvements to the socket wrench apparatus shown in that prior patent, the present invention is intended to allow the teachings of that prior patent to be more readily adapted to wrenches and tool or workpiece holders of other types and configurations. 
         [0002]    The teachings and content of the &#39;467 are expressly incorporated herein by reference as if fully set forth herein as well. In particular, the present invention teaches the use of a different web/cam pin assembly, which can be used in place of that shown in FIGS. 6 and 7 of the &#39;467 patent. The general purpose, structure, and function of the invention are the same as that described in the &#39;467 patent, except as is indicated herein. 
         [0003]    Briefly, and by reference to the &#39;467 patent, the web/cam pin assembly of that patent included a web  36  formed of resilient material, such as the plastic material indicated in that &#39;467 patent, which connected to and retained longitudinally extending members  40 , typically referred to as cam pins or longitudinal arms. These arms  40  included notches or reduced areas  42 , intermediate the ends of the arms, which served to allow web  36  to hold the arms in place. The overall orientation of the web/cam pin assembly was as a longitudinally extending cylinder about axis AA, as shown in  FIG. 1  of the &#39;467 patent. 
         [0004]    Commercial embodiments of the invention taught by the &#39;467 patent have been successful and widely adopted. However, experience through the years of such products has shown that in certain instances the invention does not work as well as would be desired. For example, it has been found to be not uncommon practice for workers faced with extensively rusted or corroded bolts to first attempt to loosen the bolt by heating it with a torch or similar device. Once so heated, the bolt (and/or a nut attached to it) retains that heat for a significant period of time. When wrenches using the invention of the &#39;467 patent are then applied to the heated workpiece (either to the bolt head or the nut), a substantial thermal gradient exists between the temperature of the workpiece and the temperature of the wrench. That thermal gradient has been found, on occasion, to be sufficient to degrade the performance of the plastic web holding the cam pins or arms in place, occasionally to the point of even melting or burning the web up and allowing the arms to fall out of the wrench after the workpiece is removed. 
         [0005]    Obviously, the same problem could theoretically occur as a result of merely using wrenches of that type in elevated temperatures where the thermal gradient was zero, except that such wrenches are not normally stored at such elevated temperatures or readily used in such environments. However, the reverse problem has been noted as a potential, i.e., when wrenches of the type taught by the &#39;467 patent are used a substantially lower temperatures than the particular plastic selected for use as web  36  was designed for. This could occur, for example, in extreme Northern climates or during periods of substantially lower than normal outdoor temperatures, where the plastic material of web  36  could become brittle or have substantially reduced elasticity. 
         [0006]    Also, the construction of the wrench taught by the &#39;467 patent, while efficient and economical in design, could be vulnerable to damage caused by less careful use. For example, in the construction illustrated in the &#39;467 patent, the plastic web was directly accessible to the exterior environment by any object capable of entering the open end of the socket wrench. Sharp objects doing so could scratch or cut the web in part. Occasionally, the workpiece being used with the wrench could have such surfaces or projections thereon which impact and damage the web, especially over an extended period of use. Similarly, sand, crystalline materials, and like debris could also contact the web through the open end of the socket wrench, if, for example, the wrench was dropped onto such materials. Excessive instances of that happening could eventually degrade the functional capabilities of the wrench. Further, users may on occasion use certain solvents on stuck bolts or work pieces prior to applying wrenches of the type taught by the &#39;467 patent. Depending upon the chemical nature of the solvent and of the plastic material selected for web  36 , there may be an adverse chemical reaction which degrades the web if that solvent is allowed to contact the web. 
         [0007]    Moreover, while the specific plastic material suggested for web  36  in the &#39;467 patent may be suitable for most applications, there are practical limits to the strength of plastic materials, given the cost of certain plastic compositions and the compressibility needed to be assembled into the wrench and flex upon workpiece insertion. A plastic web may not permit higher forces to be applied to the wrench in certain circumstances, without driving production costs too high for effective marketing. 
         [0008]    In other situations the sheer mass of the plastic needed for the web can be an issue. When applying the invention of the &#39;467 patent to rather small wrenches or tool holders, the extent of compression and/or tension available to the web because of the reduced size or mass of the web can significantly reduce the preferred degree of functionality. Similarly, the dimensional extent of notches  42  in arms  40  that are often required for the web to most effectively engage and retain arms  40  can, on occasion, significantly reduce the strength available for those arms. 
         [0009]    Further, it has been found that over time and in certain instances, the utilization of a single web member for biasing the cam pins or arms, positioned where it is, can permit permanent deformation or “bending” of portions of the wrench components which degrades overall performance. In addition, as with any product, it is always desirable to find ways to assemble the product more efficiently and reduce production costs. Also, the specific structural format taught in the &#39;467 patent, is not readily adaptable to as wide a range of tools as would be desired, particularly because of the web configuration and the formats available for retaining that configuration into applicable housings. 
         [0010]    Accordingly, it is an object of the present invention to provide an improved method and apparatus for workpiece manipulation. More specifically, objects of the present invention include providing a wrench system or workpiece holder which:
       a. has improved functionality over a greater range of temperatures,   b. is more durable over time,   c. has improved resistance to degradation of performance over a wider range of usage environments and user practices,   d. is usable with a wider range of application force,   e. is easier to manufacture and can be manufactured at lower costs, and   f. is more readily adapted to a wide variety of workpiece holders.       
 
       SUMMARY OF THE INVENTION 
       [0017]    These and other objects of the present invention are obtained by the provision of an assembly of the spaced apart cam pins (or longitudinal arms) for the wrench which is radially biased and retained by metal spring elements formed in circumferential rings, spaced apart along the length of the arms, and acting upon adjacent arms. These spring rings are protected by intervening retention rings used to secure the assembly into the wrench housing. One or more of the spring rings can be secured to the end face of the arms, by a locking interface with notches in the end faces. A circumferential ring used intermediate the end faces of an arm can use a dimension reduction of the arm cross section in order to secure the arm. Alternatively, using spring rings at each end of the arms, with a shielding retention ring adjacent each spring ring, permits the camming functionality of the assembly to be readily utilized in more conventional wrenches. 
         [0018]    Other objects, advantages, and novel features of the present invention will become more readily apparent from the following drawings and detailed description of preferred embodiments of this invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is an exploded, front perspective view of a socket wrench socket embodying the present invention. 
           [0020]      FIG. 2  is a cross sectional view of the embodiment of  FIG. 1 , as assembled. 
           [0021]      FIG. 3  is a front end view of the embodiment of  FIG. 1 , as assembled. 
           [0022]      FIG. 4  is a front perspective view of the web/arm assembly of the embodiment of  FIG. 1 , removed from the socket wrench. 
           [0023]      FIG. 5  is a front end view of the web/arm assembly of the embodiment of  FIG. 1 . 
           [0024]      FIG. 6  is a front perspective view of a single arm of the embodiment of  FIG. 1 . 
           [0025]      FIG. 7  is an exploded, front perspective view of an alternative wrench embodying the present invention. 
           [0026]      FIG. 8  is a cross sectional view of the embodiment of  FIG. 7 , as assembled. 
           [0027]      FIG. 9  is a front perspective view of the web/arm assembly of the embodiment of  FIG. 7 . 
       
    
    
       [0028]    The drawings are not intended to be to scale from one drawing to the next, some enlargement being used to facilitate understanding of the invention. 
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0029]      FIGS. 1-6  show one embodiment of the present invention, in the format of a socket wrench of the type shown in th &#39;467 patent.  FIGS. 7-9  show an alternative embodiment of the present invention in a different type of wrench  11 , but with similar invention functionality as was taught in the &#39;467 patent. The present invention expressly contemplates applications in a wide variety of wrench and tool holder types, where ever the functional attributes of this invention are desirable (and those functional attributes are elaborated upon herein and in the &#39;467 patent). Moreover, even within each of these two illustrated embodiments of wrench types, there are significant alternative embodiments envisioned by the present invention. 
         [0030]    For example, comparing the spring rings shown with respect to the two wrench types, concave springs are shown with  FIG. 1  while convex springs are shown with  FIG. 7 , but either type of spring can be used with either wrench type. Also, in  FIG. 1  the spring rings are shown with both spring rings being intermediate the ends of the arms. However, the present invention also envisions the spring rings of that embodiment could use one intermediate the ends of the arms and the other at a notched end face, such as is used in the embodiment of  FIG. 7 . Similarly, in  FIG. 1  the retaining ring has a plurality of circumferential projections to engage the interior wall of the socket housing, but in  FIG. 7  the retaining ring is of a split ring format which is radially compressible and biased to exert retention force over its entire circumference. Either type of ring can be used with either wrench type, as preferred in a given manufacture. Further, the spacer in  FIG. 1  is illustrated to be a separate element from the spring rings, but in alternative embodiments that element can be formed integrally with one or more of the spring rings. Similarly, the need for a spacer is absent in the embodiment of  FIG. 7  since the function of that element is inherent in the arms themselves because of the end face mounting, in other embodiments the need for a separate spacer element can be absent as well because of integration of that function in the cross section dimensional configuration of the arms or, in the case of embodiments using only a single spring ring, of the passageway through or interior wall of the socket housing. 
         [0031]    Accordingly, the detailed discussion herein should not be considered to be an enumeration of the only embodiments applicable or contemplated for the present invention. 
         [0032]    Briefly,  FIG. 1  shows a socket body or housing  10  of a socket wrench wherein the assembly of the present invention can be mounted. Housing  10  includes a passageway  12  which extends at least partially (and preferably completely) through the housing along longitudinal axis  14 . As explained in the &#39;467 patent, and as shown in the drawings of this application, that passageway is configured with slots and/or recesses to receive the web/cam pin or web/arm assembly  16 . Opening  18  of passageway  12  received the workpiece upon which the wrench is intended to apply rotational force, about axis  14 . Opening  20  of passageway  18  and/or into housing  10  is intended to receive the rest of the socket wrench tool, such as is used to transmit force to housing  10 . 
         [0033]    In the embodiment of  FIG. 1 , web/arm assembly  16  includes, for example, a plurality of spaced apart longitudinal arms  22 , positioned circumferentially about assembly  16  and mounted within housing  10  approximately equidistant from axis  14 . Although those arms have been improved upon in the present invention, the function of those arms is substantially similar to members  40  in the &#39;467 patent, i.e., serving as cam arms to engage the workpiece and transmit rotational force thereto through flat inner surfaces  24 , facing radially inward toward axis  14  (the radial directions referred to herein are with reference to axis  14 ). The opposing sides  26  of arms  22  are formed with a curved, camming surface for engaging a portion of the inner wall  28  of passageway  12 . Arms  22  extend longitudinally along axis  14  and terminate at end faces  30  and  32 . End face  30 , being aligned with opening  18 , can, for example, be formed with an inclined or chamfered inner surface  34  to facilitate reception of work pieces. End face  32 , being interior of passageway  12  and generally sheltered from work pieces by the configuration of housing  10 , can, for example, be formed with a notch  36  or be a flat face. If formed with a notch, this notch can be used to receive and retain one of the spring rings, as describe further herein with respect to the embodiment of  FIG. 7 . A portion  38  of the cross sectional configuration of arm  22  or a like dimension can be reduced or notched to received a spring ring mounted intermediate the length of arm  22 . 
         [0034]    In the embodiment of  FIG. 1 , web/arm assembly  16  also includes a first spring ring  40  and a second spring ring  50 , both of which are mounted intermediate the ends of each arm  22 , along portion  38 . Alternatively, in certain embodiments those spring rings could be mounted to arms  22  via an interference or press fit, rather than using a dimensional reduction or notched portion  38 . Each of spring rings  40  and  50  include apertures  42  and  52 , respectively, for receiving arms  22 . Six such apertures are illustrated, along with six corresponding arms  22 , but the present invention is no limited to that number of arms. The number of arms is, preferably, established to correspond to the configuration of the work pieces which the invention is expected to be most commonly applied to. Six sided bolts being common in the United States, six arms were selected for illustration. Between each of apertures  42  and  52 , spring elements or members  44  and  54 , respectively, are disposed. In the embodiment of  FIG. 1 , these spring members are formed to be concave with respect to axis  14  (meaning that the “bend” of the spring is downward toward that axis). In contrast, the corresponding spring members in the embodiment of  FIG. 7  are convex with respect to axis. However, the particular configuration of the spring can be varied as desired from one application to the next so long as the function of those springs is not adversely affected. The function of those springs is to retain arms  22  in relative position with respect to each other and to apply radial biasing force to arms  22  against motion of the arms radially away from axis  14 . These spring rings are intended to improve upon and replace the function of web  36  of the &#39;467 patent. Spring rings  40  and  50  enable web/arm assembly  16  to apply retention force to the workpiece once it is inserted into housing  10 , since, in doing so, the workpiece would move arms  22  radially outward from axis  14 . Thus, once inserted into housing  10 , removal of the workpiece is resisted by the retention force. 
         [0035]    Spring rings  40  and  50  serve as narrowly dimensioned biasing elements at different positions along arms  22 , in contrast to the use of a single biasing element of greater width in the &#39;467 patent. Spring rings are, preferably, spaced apart along arms  22  and held in that relation by spacer means or ring  60 . Spring rings are, for example, formed from metal material, such as steel, and is preferably resistant to deformation and loss of spring temper over a significantly wide temperature range. Ring  60  may be formed of any desired material sufficient to withstand the limited compressive forces exerted upon it and the environmental forces it faces during operation of the socket wrench. Often, however, it will be most convenient to form spacer rings  60  from steel or a similar metal. If only a single spring ring is used with housing  10  in a given application, the function of spacer  60  can be provided by a step or ledge in inner wall  28  toward opening  20 . 
         [0036]    In the embodiment of  FIG. 1 , web/arm assembly  16  is held in place within housing  10  via a retainer ring  70 . This ring also serves as a shield member to protect spring ring  40  from impact and/or contact with items entering opening  18 , due to its dimensions and position adjacent and covering spring ring  40  in the direction of opening  18 . Further, ring  70  serves as an abutment or stop for the workpiece upon insertion into housing  10 . Ring  70  includes, for example, a plurality of radially extending projections  74  (disposed about its circumference) which can be bent slightly upon insertion into passageway  12 , but which spring back out at least slightly when reaching enlargement  72  of passageway  12 . In this manner, the web/arm assembly is restrained from removal from housing  10  once positioned therein during manufacture and/or servicing. Preferably, ring  70  is formed from metal material, such as steel, and is preferably resistant to deformation and loss of spring temper over a significantly wide temperature range. Ring  70  should also be formed from or coated with material sufficient to withstand the limited compressive forces exerted upon it and the environmental forces it faces during operation of the socket wrench. 
         [0037]    Elements of the embodiment of  FIG. 7  are numbered to correspond with like elements (in terms of general function) of the embodiment of  FIG. 1 , except for the addition of the alphanumeric “a.” The structural distinctions between the two embodiments include that housing  10   a  has opening  28   a  on opposing sides of that housing, so as to received work pieces on either side, somewhat in the manner of many conventional wrenches. Further, spring rings  40   a  and  50   a  have keyed portions  43  and  53 , respectively, rather than apertures  42  and  52 . Preferably, keyed portions  43  and  53  are formed to closely fit within notches  36   a  in arms  22   a.  Thus, arms  22   a  are engaged at their end faces by the spring rings, with no need for dimensional reduction of their cross sections intermediate the end faces (and correspondingly no need for reduction in the strength of arms  22  along their longitudinal length). Also, retainer rings  71  are of a conventional split-ring type positioned to shield and retain each of the spring rings within passageway  18   a  by expansion within enlargements  72   a  after initial compression into openings  28   a.  Retainer rings  71  are, for example, illustrated to work in combination to prevent removal of the web/arm assembly  16   a  from either end of housing  10   a.    
         [0038]    In still other alternative embodiments, the connection between the spring rings and the arms can be made via other mechanical connections, as is convenient in a given manufacturing operation or usage application, without departing from the primary functional characteristics of the present invention. In terms of the spring rings of the present invention, it is preferable in given applications that they apply radial biasing force to the arms via circumferentially continuous rings, although in a given application it may be advantageous to apply the spring biasing force via discrete and discontinuous elements, provided that the orientation of the arms is not adversely affected with respect to the camming function of applying force to the workpiece upon rotation of the wrench or tool. 
         [0039]    As will now be understood by those of skill in the art, the spring rings of the present invention substitute spring force for compression/tension forces in radial biasing of longitudinal arms  22 , by comparison with the invention described in the &#39;467 patent. Those spring forces are directed to and between each pair of circumferentially adjacent arms, and may permit, in a given instance, greater differential in the radial biasing forces applied to given arms  22 , according to uneven configurations of the workpiece circumference entering the tool housing. Moreover, the use of a pair of spring rings as the radial biasing means permits the security of system redundancy in the event of a partial failure or failure of a single spring ring. 
         [0040]    Although the present invention has been described herein with respect to specific embodiments, it must be understood that was done by way of illustration and example. The spirit and scope of the present invention is intended to be limited only by the scope of the following claims.