Abstract:
A rotary impact tool includes a housing structure with a plurality of apertures therein, an impact mechanism disposed within the housing structure, a detachable drive end mechanism coupled to the impact mechanism, and a retaining structure received by the apertures. The impact mechanism is coupled to the detachable drive end mechanism by a splined sleeve. The detachable drive end mechanism includes a detachable drive end and a collar which engages the retaining structure. Several embodiments of collars and retaining structure are disclosed.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The subject matter of this application relates to power hand tools. More particularly this application relates to power hand tools of the rotary impact type.  
           [0002]    There are a number of rotary impact tools in the prior art. These devices, often called impact wrenches, typically have an impact mechanism which generates a rotational movement by rapidly delivering a succession of rotational blows to a driven member. The driven member would typically have a drive end which is detachably engaged to a socket or other tool.  
           [0003]    While the prior art impact wrenches will generally work for their intended purpose, the high torque applications in which these impact wrenches are used and the frequency with which these tools are used often place high stress on the drive end. Consequently, the drive end, at times, may fracture or deform. Since the drive end is an integral part of the impact wrench, the impact wrench is effectively disabled without a functioning drive end. Consequently, the user is often left unable to complete a task when a drive end is broken.  
           [0004]    Due to the complexity of the design of typical impact wrenches, repair of a disabled drive end is often only undertaken by manufacturer-trained technicians. In order to repair a drive end, the user must either send or deliver the broken impact wrench to the manufacturer or a repair center for repair, or else purchase a new impact wrench. The delay in repairing or replacing an impact wrench may significantly delay the completion of a task.  
         SUMMARY OF THE INVENTION  
         [0005]    Generally, this application relates to an improved rotary impact tool which avoids the disadvantages of prior art tools while affording additional structural and operating advantages.  
           [0006]    An important feature is the provision of a rotary impact tool which is of relatively simple design and economical structure.  
           [0007]    Another important feature is the provision of a rotary impact tool with an easily removable drive end.  
           [0008]    Another important feature is the provision of a drive end that is easily detachable.  
           [0009]    In connection with the foregoing features, yet another feature is the provision of a method of removing and replacing a drive end. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    For the purpose of facilitating an understanding of the subject matter sought to be protected, there is illustrated in the accompanying drawings an embodiment thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.  
         [0011]    [0011]FIG. 1 is a fragmentary, sectional view of a rotary impact tool with a detachable drive end mechanism and retaining structure therefor;  
         [0012]    [0012]FIG. 2 is a reduced, side elevational view of the detachable drive end of the tool of FIG. 1;  
         [0013]    [0013]FIG. 3 is a front elevational view of a collar and a retaining clip of the tool of FIG. 1;  
         [0014]    [0014]FIG. 4 is a front elevational view of the rotary impact tool in FIG. 1 showing interaction between the retaining structure and the detachable drive end mechanism;  
         [0015]    [0015]FIG. 5 is an exploded, perspective view of the retaining structure and the detachable drive end mechanism of FIG. 1.  
         [0016]    [0016]FIG. 6 is a view similar to FIG. 4 showing an alternate form of retaining structure;  
         [0017]    [0017]FIG. 7 is a fragmentary view similar to FIG. 1 of the retaining structure of FIG. 6;  
         [0018]    [0018]FIG. 8 is a view similar to FIG. 6 of another form of retaining structure;  
         [0019]    [0019]FIG. 9 is a view similar to FIG. 7 showing the retaining structure of FIG. 8;  
         [0020]    [0020]FIG. 10 is a view similar to FIG. 6 of another form of retaining structure;  
         [0021]    [0021]FIG. 11 is a view similar to FIG. 7 of the retaining structure of FIG. 10;  
         [0022]    [0022]FIG. 1A is an enlargement of a portion of FIG. 11;  
         [0023]    [0023]FIG. 12 is a view similar to FIG. 6 of another form of retaining structure and drive end mechanism;  
         [0024]    [0024]FIG. 13 is a view similar to FIG. 12 of another form of retaining structure;  
         [0025]    [0025]FIG. 14 is a view similar to FIG. 12 of another form of retaining structure in a retaining condition; and  
         [0026]    [0026]FIG. 15 is a view similar to FIG. 14 showing the retaining structure in a release condition. 
     
    
     DETAILED DESCRIPTION  
       [0027]    Referring to FIG. 1, there is illustrated a rotary impact tool  10  having a housing structure  11  which includes a housing  12 , which may be formed of a suitable metal, or could be formed of a suitable plastic material, and defines an internal cavity. Disposed within the housing  12  is an impact mechanism  13  of known construction, which is coupled to a motor (not shown), the impact mechanism  13  typically including a hammer (not shown) and an anvil  14 . Typically the hammer is driven by the motor for delivering repeated rotational impacts to the anvil  14 , all in a known manner, for intermittently rotating the anvil  14 . The anvil  14  has a splined end  15  which is disposed within and in meshing engagement with the rear end of a splined sleeve  16  which is rotatably mounted within a bearing  17 . The forward end of the housing  12  defines a cylindrical opening  18  into the cavity, in which is disposed an annular oil seal  18   a  which seats against the front ends of the splined sleeve  16  and the bearing  17 . Formed laterally through the housing  12  adjacent to the front end thereof, are two apertures in the nature of cylindrical bores  19  which extend parallel to a diameter of the housing  12  on opposite sides thereof, intersecting the opening  18 .  
         [0028]    Referring also to FIGS. 2, 4, and  5 , the rotary impact tool  10  includes a detachable drive end mechanism which includes a drive end  20  which has a cylindrical body  21  with a drive square  22  projecting forwardly therefrom. Integral with the body  21  at the rear end thereof and extending laterally outwardly therefrom is an annular flange  23 . Projecting rearwardly from the flange  23  is a reduced-diameter portion  24  provided at it&#39;s distal end with circumferentially spaced splines  25  designed for a mating engagement with the splines of the sleeve  16 . In assembly, the splined end of the detachable drive end  20  is inserted into the housing opening  18 , through the oil seal  18   a  and into meshing engagement in the front end of the splined sleeve  16 , as can best be seen in FIG. 1, until the flange  23  seats against the oil seal  18   a , which serves as a mechanical stop.  
         [0029]    Referring also to FIG. 3, the detachable drive end mechanism includes an annular collar  31  having a cylindrical body  32 . Formed in the outer surface of the body  32  at the front end thereof or two parallel flats  33  on opposite sides of the central axis and respectively defining coplanar shoulders  34  which lie in a plane perpendicular to the central axis. The collar  31  has an outer diameter slightly less than the diameter of the housing opening  18  and an inner diameter slightly greater than the outer diameter of the body  21  of the detachable drive end  20 . In assembly, the collar  31  is fitted over the forward end of the detachable drive end  20  and seated against the flange  23  of the detachable drive end  20 . In this regard, a suitable annular groove  32   a  may be formed in the rear end of the collar  31  to accommodate the flange  23  (see FIGS. 1 and 5).  
         [0030]    A retaining structure  30  includes a clip  35  which may be formed of a flexible and resilient material, such as a spring steel or the like, having a bight  36  and a pair of legs  37  which converge slightly toward their distal ends, at which ends the legs are respectively provided with short outturned feet  38 . In assembly, once the collar  31  has been installed in place, the legs  37  of the clip  35  are spread sufficiently to permit them to be respectively inserted into the lateral bores  19 , so that the legs  37  respectively pass over the flats  33  of the collar  31  for engagement with the shoulders  34 , until the bight  36  seats against the outer surface of housing  12  (see FIG. 4). The outturned feet  38  serve to frictionally hold the clip  35  in place in the lateral bores  19 , the clip retaining the collar  30 , which in turn retains the detachable drive end  20 . For removal of the attachable drive end  20 , the clip  35  is removed, permitting the drive end and the collar  31  to be pulled out of the tool.  
         [0031]    Referring to FIGS. 6 and 7, there is illustrated an alternative embodiment of retaining structure, generally designated by the numeral  40 . In this case, instead of parallel radial bores receiving a clip, there are formed in the housing  12 , adjacent to the front end thereof, two diametrically aligned apertures in the form of radial bores  41 . Also formed in the outer surface of the housing  12  and communicating with the bores  41  is an annular groove  42 . Cylindrical retaining pins  43  are respectively inserted in the radial bores  41  to respectively seat on the flats  33  of the collar  31 , each pin  43  having a length such that, when seated on the flat  33 , it extends upwardly into the associated bore  41 , the pins  43  being retained in place by an O-ring  44  seated in the groove  42 . In order to remove the detachable drive end  20 , the O-ring  44  is removed and the pins  53  are dropped out of the radial bores  41 , whereupon the drive end  20  can be grasped and pulled out along with the collar  31 .  
         [0032]    Referring to FIGS. 8 and 9, there is illustrated another embodiment of retaining structure, generally designated by the numeral  50 . In this case, diametrically aligned bores  51  are formed in the housing  12  for respectively receiving pins  53 . The pins  53  are respectively biased radially outwardly into the bores  51  by leaf springs  55 , respectively disposed in front of the collar shoulders  34 , with the opposite ends of each spring  55  respectively bearing against the ends of the associated collar flat  33 . A similar retaining structure, generally designated  50   a , is shown in FIGS. 10 and 11, the basic difference being that each pin  53  is provided with a radially outwardly projecting extension  56 . Referring to FIG. 11A, the pins  53  in both of the retaining structures  50  and  50   a  may be provided with a laterally outwardly projecting flange  54 , which has a diameter greater than that of the radial bore  51  to prevent the pin  53  from escaping radially outwardly through the bore  51 . These flanges  54  bear against the shoulder  34  of the collar  31  to retain them in place. Alternatively, the pins  53  could be fixed to the leaf springs  55 .  
         [0033]    In order to remove the detachable drive end  20 , using the retaining structure  50  of FIGS. 8 and 9, a suitable tool may be inserted in the radial bores  51  to depress the pins  53  against the urging of the leaf springs  55  until the pins  53  clear the inner ends of the bores  51 , whereupon the drive end  20  can be withdrawn. In the embodiment of FIGS. 10 and 11, no tool is needed. The extensions  56  have a length such as to project outwardly of the outer surface of the housing  12 , so that they can be manually depressed with the user&#39;s fingers to disengage the pins  53 . In this case, narrow notches  52  are formed in the front end of the housing  12  communicating with the bores  51  to permit passage of the pin extensions  56  when the drive end  20  is removed.  
         [0034]    Referring to FIG. 12, there is shown another alternate form of retaining structure, designated  60 , which utilizes the same pins  53  described above in connection with FIGS. 8 and 9. However, in this case the drive end mechanism includes a modified cylindrical collar  61  having a radially outwardly extending annular flange  62  at its rear end. Laterally extending ledges  63  join the outer surface of the collar  61  to the front surface of the flange  62 . Seated on the ledges  63  are helical compression springs  64 , which respectively resiliently bias brackets  65  outwardly. In particular, each bracket  65  has a lug  66  extending into the associated spring  64  and frictionally secured thereto. The lengths of the brackets  65  are such as to engage the inner ends of the pins  53  for holding them in the bores  51 . Suitable tools can be used to depress the pins  53  and the brackets  65  against the urging of the springs  64  to release the drive end mechanism. A similar retaining structure, designated  60   a , is shown in FIG. 13, the difference being that each bracket  65  is provided with an extension  67  projecting outwardly through a suitable opening  69  in the housing  12  and having a head  68  for manually depressing the bracket  66  with the user&#39;s fingers. Slots (not shown) in the front end of the housing  12  may communicate with the openings  69  to facilitate removal of the retaining structure  60   a  with the drive end  20 , similar to the arrangement described above with respect to FIGS. 10 and 11. In both of the embodiments of FIGS. 12 and 13 the pins  53  could be connected to the brackets  65 .  
         [0035]    Another embodiment of retaining structure, designated  70  is shown in FIGS. 14 and 15, which utilizes the collar  61  of FIGS. 12 and 13. In this case, the housing structure  11  includes a rotatable ring  72  mounted on the end of the housing  12 . The springs  64  bias pins  71  into engagement with the inner surface of the ring  72 . The pins  71  seat in tapered notches  73  on the inner surface of the ring  70  in a locked position shown in FIG. 14 to hold the drive end  20  in place. To remove the drive end  20 , the ring  70  is rotated in the direction of the arrow in FIG. 15, the notches  73  cammingly depressing the pins  71 , so that they can ride up out of the notches to free the drive end  20 .  
         [0036]    The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments 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 broader aspects of applicants&#39; contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.