Abstract:
A composite box end wrench has a non-metallic body including a handle portion and at least one head portion which defines a fastener-receiving opening therethrough. The wrench includes strengthening and/or retaining structure which strengthens the head portion and can change the failure mode to confine wrench parts in the event of failure. In one embodiment each head portion has a fastener-engaging member insert molded therein along with a reinforcing plate which encircles the member and preferably extends slightly into the handle portion. The reinforcing structure could alternatively be a band extending the length of the wrench and encircling the fastener-engaging member (or members in a double-ended wrench). In a ratcheting version of the wrench the non-metallic body may be split lengthwise into two parts, each of which has reinforcing structure embedded therein, the fastener-engaging member being a ratchet gear which, along with an associated pawl, is disposed between the body parts. The parts may either confine or expose a peripheral portion of the gear, and the reinforcing structure encircles hub portions of the pawl and gear to the hold them together. The body parts may be secured together by various means, including pinning, ultrasonic welding and snap-fitting. The wrench body may be provided with an outer non-metallic sheath, in addition to or in lieu of the reinforcing structure, which sheath covers at least the handle portion of the body.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to hand tools, such as wrenches, and particularly to tools formed of non-metallic materials. The invention has particular application to wrenches, such as box end wrenches, of both the ratcheting and non-ratcheting type.  
           [0003]    2. Description of the Prior Art  
           [0004]    The present invention is an improvement of composite wrenches of the type disclosed, e.g., in U.S. Pat. No. 5,394,773 and in copending U.S. application Ser. No. 08/784,527 filed Jan. 17, 1997. Both the patent and the copending application relate to composite box end wrenches with fastener-engaging inserts, the copending application disclosing a ratcheting wrench wherein the ratchet mechanism is confined in a module, which is insert molded in the head end of the wrench body. These prior composite wrenches, which are compression molded of sheet molding compound, afford important electrically insulating, non-sparking and non-marring qualities. However, it has been found that, when such wrenches are injection molded of high-strength plastic material, they can break apart during testing to failure.  
           [0005]    Another problem typically experienced in ratcheting box wrenches is that, during application of high torque, the torquing forces tend to try to pull the ratchet gear away from the pawl. In very high torque applications this can cause malfunction of the ratchet mechanism. This problem is alleviated by the encapsulating module utilized in the aforementioned copending application, because the module housing engages the hubs of both the pawl and the gear for holding them together. However that arrangement is relatively expensive to manufacture.  
         SUMMARY OF THE INVENTION  
         [0006]    It is a general object of the invention to provide an improved composite wrench which avoids the disadvantages of prior wrench constructions while affording additional structural and operating advantages.  
           [0007]    An important feature of the invention is the provision of a composite box end wrench with a fastener-engaging insert which is reinforced so as to strengthen the wrench by increasing the surface area of the interface between the insert and the composite material to reduce stresses at the interface.  
           [0008]    Still another feature of the invention is the provision of a ratcheting box end wrench of the type set forth, wherein the reinforcing structure serves to inhibit separation of the ratchet pawl and gear during high torque operations in an economical manner.  
           [0009]    Yet another feature of the invention is the provision of an injection molded composite wrench construction which retains wrench parts intact in the event of failure of the wrench.  
           [0010]    Certain features of the invention are attained by providing a box end wrench comprising a body formed entirely of non-metallic material and including a handle portion and a head portion, a fastener-engaging member embedded in and encompassed by the head portion and defining a fastener-receiving opening, and a reinforcing structure embedded in the body and encompassing the fastener-engaging member.  
           [0011]    Other features of the invention are attained by providing a ratcheting box end wrench comprising a housing including two parts formed of non-metallic material and each having a handle portion and a head portion which defines an opening, each of the head portions including reinforcing structure embedded therein and encompassing the opening, the parts being joined together to form a wrench body having a handle formed by the handle portions and a head formed by the head portions with the openings aligned to define a hole through the head, and a fastener-engaging member captured between the head portions and disposed in the hole for engagement with the reinforcing structures.  
           [0012]    Still other features of the invention are attained by providing a wrench comprising an inner solid body formed entirely of a first non-metallic material and including a handle portion and a head portion having a fastener-receiving opening therein, and an outer sheath formed of a second non-metallic material and surrounding at least the handle portion of the inner body.  
           [0013]    The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    For the purpose of facilitating an understanding of the invention, there is illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, the invention, its construction and operation, and many of its advantages should be readily understood and appreciated.  
         [0015]    [0015]FIG. 1 is a perspective view of a ratcheting box end wrench with a two-part body constructed in accordance with a first embodiment of the present invention, with portions removed to foreshorten the illustration;  
         [0016]    [0016]FIG. 2 is a top plan view of a reinforcing plate used in the wrench of FIG. 1;  
         [0017]    [0017]FIG. 3 is a reduced top plan view of one part of the two-part body of the wrench of FIG. 1, and illustrating the ratchet mechanism at one end of the wrench;  
         [0018]    [0018]FIG. 4 is a view in vertical section taken along the line  4 - 4  in FIG. 3;  
         [0019]    [0019]FIG. 5 is an enlarged, fragmentary, sectional view of a portion of a mold for forming the body part of FIG. 4;  
         [0020]    [0020]FIG. 6 is a side elevational view of a ratcheting box end wrench in accordance with another embodiment of the invention;  
         [0021]    [0021]FIG. 7 is a top plan view of the wrench of FIG. 6, with the central portion of the upper part broken away;  
         [0022]    [0022]FIG. 8 is a view similar to FIG. 6 of another embodiment of the present invention;  
         [0023]    [0023]FIG. 9 is an enlarged view in vertical section illustrating an alternative technique for holding together the parts of the wrenches of FIGS.  1 - 8 ;  
         [0024]    [0024]FIG. 10 is a fragmentary view similar to FIG. 3, illustrating an alternative form of reinforcing structure;  
         [0025]    [0025]FIG. 11 is a fragmentary side elevational view in partial section of a non-ratcheting box end wrench in accordance with another embodiment of the invention;  
         [0026]    [0026]FIG. 12 is a fragmentary sectional view taken along the line  12 - 12  in FIG. 11;  
         [0027]    [0027]FIG. 13 is a top plan view of a non-ratcheting box end wrench incorporating a reinforcing structure in accordance with another embodiment of the invention;  
         [0028]    [0028]FIG. 14 is a fragmentary top plan view of another wrench similar to that of FIG. 13, incorporating yet another embodiment of reinforcing structure;  
         [0029]    [0029]FIG. 15 is a side elevational view in partial section of a wrench similar to that of FIG. 11, in accordance with still another embodiment of the invention;  
         [0030]    [0030]FIG. 16 is a sectional view taken along the line  16 - 16  in FIG. 15; and  
         [0031]    [0031]FIG. 17 is a fragmentary view similar to the right-hand end of FIG. 15, illustrating another alternative embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]    Referring to FIGS.  1 - 5 , there is illustrated a hand tool in the nature of a ratcheting box end wrench  20 , constructed in accordance with and embodying the features of a first embodiment of the present invention. The wrench  20  has a non-metallic body  21  including an elongated handle  22  provided with heads  23  and  24  at the opposite ends thereof, which may be of the same or different sizes. The body  21  is formed of two molded parts  25  which are substantially identical in construction, wherefore like portions of each part will bear the same reference numbers, although one has been designated  25 A so that the two parts can be distinguished. Preferably, each of the parts  25  and  25 A is injection molded of a non-metallic material, preferably a high-strength polymer, such as a 60% glass-filled nylon material. Each part has an elongated handle portion  26  provided at the opposite ends thereof with head portions  27  and  28 , the parts  25  and  25 A being joined with their inner sides facing each other along a parting line  29 , so that the handle portions  26  form the handle  22 , the head portions  27  form the head  23  and the head portions  28  form the head  24 .  
         [0033]    Each of the parts  25  and  25 A includes an elongated, substantially flat base wall  30  provided around the periphery thereof with an upstanding peripheral side wall  31 , the opposite sides of which are joined by transverse walls  32  and  33 , respectively adjacent to the opposite ends of the handle portion  26 . Projecting from the inner surface of the base wall  30  substantially the same height as the peripheral side wall  31  are three hollow cylindrical bosses  34 , two of which are respectively integral with the facing sides of the transverse walls  32  and  33 . Each of the transverse walls  32  and  33  has formed on the opposite or head-facing side thereof two laterally spaced-apart and forwardly extending projections  35 . The peripheral side wall  31  has a flat planar end surface  36  substantially parallel to the base wall  30 , and cooperates with the transverse walls  32  and  33  to define two ratchet mechanism cavities  37 , respectively at the head portions  27  and  28 . Formed through the base wall  30  in each of the cavities  37  is a large-diameter circular hole  38 . Also formed in the base wall  30  in each cavity  37  is a smaller-diameter circular recess  39  aligned with the hole  38  axially of the wrench body  21 .  
         [0034]    Respectively insert molded in the head portions  27  and  28  are reinforcing structures in the form of two appropriately sized substantially flat, generally pear-shaped reinforcing plates  40  (see FIG. 2), preferably formed of a suitable metal, such as steel. The reinforcing plates  40  are disposed in the base wall  30  substantially parallel to the inner and outer surfaces thereof, as can best be seen in FIGS. 4 and 5, each plate  40  having a large-diameter gear hole  41  therethrough disposed substantially congruent to the hole  38  in the associated head portion  27  or  28 , and a smaller-diameter pawl hole  42  disposed substantially congruent with the associated recess  39 . Each plate  40  is disposed in the associated head portion  27  or  28  at a depth slightly above the base of the recess  39 . Each reinforcing plate also has formed therethrough two small-diameter holes  43  between the holes  41  and  42 , which are filled with the plastic material during the molding operation to assist in anchoring the reinforcing plate  40  in the part  25  and to help prevent pieces of the wrench from breaking off in the event of an overload failure.  
         [0035]    Referring to FIG. 5, there is illustrated a portion of a mold apparatus  45  usable in molding the parts  25 . This apparatus preferably includes three core pins  46  to respectively define the cylindrical bosses  34  and core pins  47  and  48  (one each shown) for respectively forming the recesses  39  and the holes  38 . While, in the preferred embodiment, the parts  25  are formed by injection molding, it will be appreciated that other types of molding could be used, such as compression molding of layers of sheet molding compound by a technique similar to that disclosed in the aforementioned U.S. Pat. No. 5,394,773.  
         [0036]    The wrench  20  also includes two ratchet mechanisms  50 , respectively disposed in the heads  23  and  24 , the ratchet mechanisms  50  being substantially identical in construction, with the possible exception of size, wherefore only one will be described in detail. The ratchet mechanism  50  includes a ratchet gear  51  having an internal fastener-engaging surface  52 , which is illustrated as having a 12-point configuration, but which could have any of a number of other different configurations, such as hexagonal, double hexagonal, square drive and the like. The gear  51  is provided at its outer periphery with radially outwardly extending and equiangularly spaced ratchet teeth  53 . The gear  51  is provided with a cylindrical hub  54  between the teeth  53  and the fastener-engaging surface  52 , which extends axially from the teeth  53  in both directions and is dimensioned to be rotatably received in the holes  38  of the associated wrench head  23  or  24 . The ratchet mechanism  50  also includes a pawl  55 , having a pivot hub or pin  56  dimensioned to be rotatably received in the recesses  39  of the wrench  20  for ratcheting engagement with the gear teeth  53 . A leaf spring  57  is seated in the space between the projections  35  and resiliently urges the pawl  55  into engagement with the gear teeth  53  in a known manner, as can best be see in FIG. 3.  
         [0037]    In assembly, the ratchet mechanisms  50  are seated in the head portions  27  and  28  of one part  25 A, as illustrated in the right-hand end of FIG. 4. Then the other part  25  is fitted over the part  25 A, so that the ratchet mechanisms  50  are respectively confined in the cavities  37 , being completely encompassed by the base walls  30  and the peripheral side walls  31  of the parts  25  and  25 A. When thus assembled, it can be seen that the gear hubs  54  fit through the holes  41  in the reinforcing plates  40 , while the pawl hubs  56  fit through the holes  42  in the reinforcing plates  40 . The parts  25  and  25 A may be fixedly secured together by suitable means, such as by pins disposed in the aligned bosses  34 . However, it will be appreciated that any of a number of different joining techniques could be used, such as suitable adhesives, ultrasonic welding and the like, with appropriate modification of the structure of the parts  25  and  25 A as would be well understood by those of ordinary skill in the art.  
         [0038]    It is a significant aspect of the invention that, when thus assembled, the reinforcing plates  40  cooperate with the gears  51  and the pawls  55  of the ratchet mechanisms  50  to significantly increase the strength of the wrench  20 , increasing the ultimate torque at which failure is likely to occur. It is also important that the reinforcing plate  40  influences the failure mode such that, when the wrench  20  is tested to failure, the wrench tends not to break apart. Also, because the reinforcing plates  40  engage the gears  51  and the pawls  55 , they positively inhibit the tendency of those ratchet mechanism parts to separate from each other during high-torque applications. All of these advantages are achieved in a relatively simple and economical construction.  
         [0039]    Referring now to FIGS. 6 and 7, there is illustrated an alternative embodiment of the present invention in the form of a ratcheting box end wrench, generally designated by the numeral  60 . The wrench  60  has a non-metallic body  61  including an elongated handle  62  provided with heads  63  and  64  at the opposite ends thereof. Again, the body  61  is formed of two substantially identical parts  65  and  65 A, each including a handle portion  66  and head portions  67  and  68 . The handle portion  66  is substantially thicker than the heads portion  67  and  68 , being joined thereto by steps or shoulders  69 . Formed in the handle portion  66  are three longitudinally spaced-apart, circular recesses  70 . Integral with each of the shoulders  69  and projecting therefrom into the adjacent head portion  67  or  68  are a pair of laterally spaced-apart projections  71 .  
         [0040]    The ratchet mechanisms  50  are assembled in the parts  65  and  65 A in substantially the same manner as was described above in connection with the wrench  20 , with each leaf spring  57  being seated between the adjacent projections  71 . The parts  65  and  65 A may be joined by pins  72  or by any of the other alternative techniques described above. There results a ratcheting box end wrench  60  which is substantially like the wrench  20 , described above, except that, because the parts  65  and  65 A do not have the upstanding peripheral side wall, the ratchet mechanisms  50  are exposed between the head portions  67  and  68 .  
         [0041]    The wrench body of FIGS. 6 and 7 could be formed of a three-part construction rather a two-part construction. Thus, referring to FIG. 8, a wrench  75  is illustrated in which each of the outer body parts has substantially the same thickness along its entire length. Instead of the steps or shoulders  69 , an intermediate spacer  76  is disposed between the handle portions of the outer parts, the spacer  76  having leaf spring seating recesses  77  formed in the opposite ends thereof and having pin holes  78  formed therethrough for receiving the joining pins  72  in the event that that joining technique is used.  
         [0042]    In addition to the joining techniques described above, the parts of the wrench body could be designed to be snap-fitted together. Thus, referring to FIG. 9, there is illustrated a wrench  80  formed of mating parts  81  and  81 A, respectively having laterally inwardly extending flanges  82  and  82 A along one side of the peripheral side wall thereof and having hooks  83  and  83 A at the opposite sides thereof, respectively having tabs  84  and  84 A designed to snap-fit into engagement with the flanges  82 A and  82 , as illustrated.  
         [0043]    While, in the preferred embodiments described above, the reinforcing structure is in the form of flat reinforcing plates  40 , it could be in the form of an elongated band. Thus, referring to FIG. 10, there is illustrated a wrench part  85 , which is substantially identical to the wrench part  25  illustrated in FIG. 3, except that the reinforcing structure is in the form of an elongated continuous band  86  defining a loop which encircles the hub  54  of the ratchet gear  51  and the hub  56  of the pawl  55 . Preferably, the band  86  is in the form of a rigid metal band which is insert molded in the part  85  in the same manner as described above.  
         [0044]    Principles of the present invention could also be applied to a non-ratcheting box end wrench. Thus, referring to FIGS. 11 and 12, there is illustrated a box end wrench  90  having a non-metallic body  91  with an elongated handle portion  92  and head portions  93  (one shown) at the opposite ends thereof. Embedded in each of the head portions  93  is an annular, fastener-engaging insert  95 , preferably formed of a suitable metal and having an axial extent substantially equal to the thickness of the associated head portion  93 . If desired, the inserts  95  could be provided on the outer cylindrical surfaces thereof with suitable knurling, ridges or the like, more securely to grip the surrounding plastic and inhibit rotation of the insert  95  in the body  91 . Preferably, the body  91  is formed by injection molding and the inserts  95  are insert molded therein. The inserts  95  are respectively disposed through complementary holes  96  in two reinforcing plates  97  (one shown), which are also insert molded in the body  91  centrally of the thickness thereof. The wrench  90  is illustrated as being of the type having offset heads, so the reinforcing plates are correspondingly offset, defining bend lines  98 . Also formed through each of the reinforcing plates  97  is a plurality of holes  99  for receiving the body material therethrough, more securely to anchor the reinforcing plates  97  in place. The reinforcing plates  97  function in substantially the same manner described above, for strengthening the wrench  90  and for shifting the failure locations from the head portions  93  toward the handle portion  92  to failure that results in multiple pieces.  
         [0045]    The reinforcing plates  97  could be replaced by a reinforcing structure in the nature of an elongated, continuous band or loop. Thus, referring to FIG. 13, there is illustrated a composite box end wrench  100  having a non-metallic body  101  including a handle portion  102  and head portions  103  and  104 , respectively having fastener-engaging inserts  105  embedded therein, as described above. Also embedded in the body  101 , as by insert molding, is an elongated, continuous, reinforcing band  106 , which loops around the inserts  105  and extends the length of the body  101 . Preferably, the opposite sides of the band  106  are held together by a plurality of fasteners  107  (two shown) between the head portions  103  and  104  to position the band  106  centrally of the handle portion  102 . The reinforcing band  106  could be formed of a suitable metal or, alternatively, could be formed of a non-metallic material of suitable strength, such as a pultruded ribbon of reinforced nylon or other suitable material of adequate strength. Also, while the inserts  95  and  105  described above are preferably formed of a suitable-strength metal, such as steel, they could also be formed of non-sparking materials, such as non-sparking metal or a non-metallic material of suitable strength, toughness and wear resistance.  
         [0046]    Referring to FIG. 14, there is illustrated another alternative embodiment of the present invention in the nature of a box end wrench  110  having a non-metallic body in which is embedded a fastener-engaging insert  115 . The wrench  110  may be substantially the same as the wrenches  90  and  100  described above, except that in this case the reinforcing structure is in the nature of a skeleton reinforcing frame  116  which, in addition to the large hole for receiving the insert  115 , has a large opening  117  and a plurality of smaller holes or openings  118  extending around the insert  115  for receiving plastic material therethrough for anchoring purposes. Again, the reinforcing frame  116  could be formed of a suitable metal or, alternatively, of a suitable-strength non-metallic material.  
         [0047]    Referring also to FIGS. 15 and 16, there is illustrated another embodiment of the present invention, which includes a box end wrench substantially identical to the wrench  90  described above in connection with FIGS. 11 and 12, except that in this case the inner body  91  of the wrench is provided with an outer sheath  120  which substantially surrounds the handle portion  92 . The sheath  120  is formed of a suitable non-metallic material which is more flexible than the inner body  91 , preferably a tough polymer, such as nylon  6 , and may be applied by over molding the handle portion  92 . Also, the sheath  120  could be formed of a material which provides a soft feel to the touch to improve the ergonomics of the wrench and for enhanced gripping characteristics. In use, the sheath  120  will serve to retain parts of the wrench intact in the event of possible overload failure. In this regard, because the reinforcing plates  97  will tend to shift the failure location into the handle portion  92 , it has been deemed necessary only encapsulate the handle portion to achieve this object.  
         [0048]    Referring to FIG. 17 there is a similar embodiment in the nature of a box end wrench  130  having a non-metallic body  131  with a handle portion  132  and head portions  133  (one shown). In this case, each of the head portions  133  has a fastener-engaging opening  135  molding directly therein, rather than being provided by an insert. In this case, where the wrench has no insert molded parts, there is provided an outer sheath  136  which covers the entire wrench body  131 , except for the inside of the fastener-engaging openings  135 . Thus, the sheath  136 , which could be applied by overmolding or dipping, will tend to retain the pieces of the wrench intact upon possible overload failure, regardless of where that failure may occur along the wrench.  
         [0049]    From the foregoing it can be seen that there has been provided an improved box end wrench of non-metallic construction, of either the ratcheting or non-ratcheting type, including embedded fastener-engaging inserts provided with reinforcing structure to strengthen the wrench and to change the failure mode thereof such that the wrench tends not to fracture into more than one piece, all while achieving a relatively simple and economical construction. There is also provided an improved wrench construction with an outer sheath for retaining parts of the wrench intact in the event of overload failure, as well as providing a more comfortable grip.  
         [0050]    While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.