Abstract:
A power tool system has detachable and interchangeable implements and driving sources. The interchangeable implements and driving sources use a housing having common mating interface to selectively assemble a power tool having the desired characteristics. A latch is used to hold a selected implement and driving source in functional engagement. An adjustable bale handle provides a comfortable and safe handhold for various configurations of the interchangeable implements.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The benefit of priority under 35 U.S.C. § 119(e) is claimed based on U.S. Provisional Application Ser. No. 60/094,082, filed Jul. 24, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to power tools. In particular, the present invention is directed to a power tool having a system of detachable and interchangeable implements. The term “power tool” includes hand-held power tools such as hedge trimmers and chain saws, as well as mechanisms which are not hand-held but whose operation is controlled by the hands of a user, e.g., lawn mowers and grinders. 
     2. Description of Related Art 
     In order to perform a desired task using a power tool, it is important to select a power tool that has the proper configuration and capacity for accomplishing the task efficiently and safely. The size and shape of the working tool, the speed and power of the driving mechanism, as well as the comfort and safety of the user must always be considered. 
     Conventionally, a user selects the appropriate tool from a collection of similar devices each having different characteristics. For example, in order to select an appropriate hand-held, powered hedge trimmer, the user must make a number of choices: whether to use a single or a double edge cutting blade, the length of the cutting blade, the shape of the cutting teeth, whether driving power should come from an electric motor or an internal combustion engine, the amount of power and speed required for driving the cutting blade, etc. Given all the permutations of these characteristics, a large collection of variously configured hedge trimmers would be required. Generally, the cost of purchasing, maintaining and storing such a large collection of hedge trimmers is prohibitive. 
     It is much more common for a user to own a single hedge trimmer that is used in every situation, regardless of how well suited the hedge trimmer is to that particular situation. Under these circumstances, the efficiency and/or adequacy of the tool is often insufficient. 
     It is also conventional for a power tool to be of fixed configuration. Specifically, it is common for each tool to have a single relative arrangement of the handle, power source and working tool. One disadvantage of such a fixed arrangement is that the user is not able to adjust the power tool for safe and comfortable operation. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to overcome these disadvantages of conventional power tools. 
     It is another object of the present invention to provide a power tool that may be readily selectively configured by the user for optimum efficiency, as well as ease and safety of operation. 
     It is yet another object of the present invention to provide an arrangement for mating a driving source with a detachable working implement selected from a range of interchangeable tools. 
     It is a further object of the present invention to provide a mating arrangement for connecting a driving source with a detachable working implement that does not require additional tools to make the connection. 
     It is yet a further object of the present invention to provide an arrangement for interchangeably supporting a working implement with respect to a driving source, and for transferring power from the driving source to the working implement. 
     The objects of the present invention are achieved by means of an attachment system for connecting a driven implement to a driving source including a power take-off accessible with respect to a main body. The attachment system comprises a housing adapted for supporting the driven implement and for matingly engaging the main body; a drive transfer adapted for matingly connecting the power take-off to the driven implement; and an implement mount adapted for supporting the driven implement for movement with respect to the housing. 
     The objects of the present invention are also achieved by means of a hand held power tool having at least one interchangeable implement. The power tool comprises a generally hollow main body having an exterior surface; a bale handle connected to the main body and adapted for gripping by the hand, the bale handle being pivotally mounted with respect to the exterior surface; a driving source being supported inside the main body and adapted for outputting mechanical energy; a power take-off transferring the mechanical energy outside the main body; a housing matingly engaging the main body in a first position, the housing adapted for supporting the implement; and a drive transfer operatively connecting the power take-off to the implement. The housing is detachably separable from the main body. 
     The objects of the present invention are further achieved by means of a power tool system for trimming hedges. The power tool system comprises a main body at least partially enclosing a driving source; a first housing adapted for mating engagement with respect to the main body, the first housing including a first set of relatively reciprocating blades adapted for being operatively driven by the driving source; and a second housing adapted for mating engagement with respect to the main body, the second housing including a second set of relatively reciprocating blades adapted for being operatively driven by the driving source. The first and second housings are interchangeably connectable with respect to the main body. 
     The objects of the present invention are yet further achieved by means of a latch arrangement for securing a housing with respect to a main body. The latch arrangement comprises at least one arm adapted for pivotal movement with respect to the main body about a pivot axis; a grip adapted for grasping to pivot the at least one arm, the grip being fixed to the at least one arm; and a cam surface on each of the at least one arm, the cam surface being adapted for biasing the housing toward the main body. The at least one arm is elastically deformed by engagement between the cam surface on each of the at least one arm and the housing. 
     The objects of the present invention are additionally achieved by means of a handle adjustment system. The handle adjustment system comprises a main body having an exterior surface; and a bale handle connected to the main body and adapted for gripping by the hand, the bale handle being pivotally mounted with respect to the exterior surface. A first one of the exterior surface and the bale handle includes at least one projection engaging at least one recess formed in a second one of the exterior surface and the bale handle, whereby cooperative engagement between one of the at least one projection and one of the at least one recess define a detent adapted for maintaining the bale handle at a pivotal position with respect to the main body. 
     The objects of the present invention are yet additionally achieved by means of an interchangeable implement for connecting to a driving source including a power take-off accessible with respect to a main body. The interchangeable implement comprises a housing adapted for supporting a driven implement and adapted for matingly engaging the main body; two female members being formed in the housing and adapted to matingly receive a corresponding male member extending from the main body, each of the female members having a mating diameter in a range of 4 to 8 millimeters and being spaced apart a center-to-center distance in a range of 50 to 70 millimeters; and two projections extending from opposite sides of the housing, each of the two projections supporting a respective roller extending at least 2 millimeters from a respective one of the opposite sides to an enlarged shoulder, and a shoulder-to-shoulder measure between the enlarged shoulders being in a range of 80 to 110 millimeters. 
     Additional objects and advantages of the invention will be set forth in the description that follows, and in part will be readily apparent to those skilled in the art from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate a presently preferred embodiment of the invention, and, together with the general description given above and the detailed description of the preferred embodiment given below, serve to explain the principles of the invention. 
     FIG. 1 is a schematic illustration of a power tool according to the present invention having a main body matingly engaging a housing of a working implement, and a latch assembly in a first, unlatched, position. 
     FIG. 2 is a schematic illustration of the power tool shown in FIG. 1, with the latch assembly in a second, latched, position. 
     FIG. 3 is a perspective view of the latch assembly shown in FIG.  1 . 
     FIG. 4 is a perspective view of a gear case portion of the power tool main body according to the present invention. 
     FIG. 5 is a perspective view of a working implement according to the present invention. 
     FIG. 6 is an exploded view of the working implement shown in FIG.  5 . 
     FIGS. 7A and 7B are perspective views of an auxiliary handle for a power tool according to the present invention. 
     FIG. 8 is a perspective view of a detail of a main body of a power tool according to the present invention. 
     FIG. 9 is a partial cross-section view of a power tool according to a preferred embodiment of the present invention. 
     FIG. 10 is a bottom plan view of a main body of the preferred embodiment of the present invention illustrated in FIG.  9 . 
     FIG. 11 is a detail view of a clutch hub according to the preferred embodiment of the present invention illustrated in FIG.  9 . 
     FIG. 12 is a side elevation view of a working implement according to a preferred embodiment of the present invention. 
     FIG. 13 is a top plan view of the working implement according to the preferred embodiment of the present invention illustrated in FIG.  12 . 
     FIG. 14 is a cross-section view taken along line XIV—XIV in FIG.  13 . 
     FIG. 15 is a detail view of a drive spud according to the preferred embodiment of the present invention illustrated in FIG.  12 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A hand-held power tool  1  is shown in FIGS. 1 and 2. The power tool  1  includes a main body  10  supporting and enclosing a driving source such as an electric motor or an internal combustion engine (not shown). The main body  10  additionally supports conventional controls and auxiliary systems (not shown) for operating the driving source. The main body  10  also provides at least one means for a user&#39;s hands to hold the power tool  1 . 
     A working implement  14  is operably connected to the driving source. For the sake of illustration, a double edge hedge-trimming implement is generically illustrated throughout the drawings. However, in accordance with the present invention, implements of different types and/or characteristics may also be used in connection with the main body  10 . One example of a different type of implement is a rotary saw, as opposed to a reciprocating saw. 
     A housing or cassette  16  connects the implement  14  to the main body  10 . The cassette  16  provides a physical connection for supporting the mass of the implement  14  with respect to the main body  10 , as well as houses a driving connection between the driving source and the implement  14 . 
     The connection between the cassette  16  and the main body  10  provides a detachable interface such that different types and/or sizes of working implements may be readily connected to the main body  10  by different cassettes  16 . Specifically, the cassette  16  provides a single type of connection for attaching a range of implements having different characteristics (e.g., type, size, etc.) to the same main body  10 . Similarly, the cassette  16  enables the implement  14  to be connected to a range of main bodies  10  having different characteristics (e.g., driving source type, power output, etc.). 
     According to the present invention, a large collection of power tools is provided by interchangeably connecting small numbers of main bodies  10  and cassettes  16 . Thus, a user is able to select the appropriate power tool for a desired task without the expense of purchasing, maintaining and storing a wide range of individual power tools. 
     According to a preferred embodiment of the present invention, as illustrated in FIGS. 1-3, a latch assembly  18  is used to secure and release the cassette  16  with respect to the main body  10 . The latch assembly  18  is pivotally mounted with respect to the gear case  12  at a pair of pivot points  20 A and  20 B on opposite sides of the gear case  12 . Spacers  19 , see FIG. 1, are interposed between the latch assembly  18  and a pair of bosses  20  (only one shown) formed on the opposite sides of the gear case  12 . This provides electrical insulation for the latch assembly  18  from the gear case  12 , drive mechanism, and blades  50 A, 50 B in the event the insulation of the power cord (for an electric powered version) is severed accidentally while operating the power tool  1 . The spacers  19 , which are preferably made of plastic, also provide a durable, low friction bearing surface for the latch assembly  18  to pivot on, as opposed to having the latches wearing into the bosses  20  on the gear case  12  when pivoted. The latch assembly  18  includes a pair of latch arms  22 A and  22 B extending substantially parallel to one another and transversely from a common grip  24  to a corresponding one of the pivot points  20 A, 20 B. According to the preferred embodiment of the present invention, each of the pivot points  20  comprises one of the two bosses  20 A′, 20 B′ on the gear case  12 , respectively, and one of two holes  20 A″ and  20 B″, respectively, on the latch arms  22 A, 22 B. Although the bosses  20  are shown formed on the gear case  12  and the holes  20 A″, 20 B″ are shown formed in the latch arms  22 A, 22 B, the bosses  20  may alternatively be formed on the latch arms  22 A, 22 B and the holes  20 A″, 20 B″ formed in the gear case  12 . 
     The latch arms  22 A, 22 B include respective cam surfaces  26 A and  26 B for engaging corresponding rollers  28 A and  28 B mounted for rotation about posts on opposite sides of the cassette  16 . The cam surfaces  26 A, 26 B and the rollers  28 A, 28 B comprise overcenter mechanisms such that as the latch assembly  18  is elastically deformed during pivoting with respect to the gear case  12 . Specifically, as the latch assembly  18  is pivoted from a relaxed (i.e., un-deformed) state to a first position, the cam surfaces  26 A, 26 B engage the rollers  28 A, 28 B so as to elastically elongate that portion of the latch arms  22 A, 22 B extending from the pivot points  20 A, 20 B to the cam surfaces  26 A, 26 B. Upon further pivoting the latch assembly  18  to a second position, the cam surfaces  26 A, 26 B remain engaged with the rollers  28 A, 28 B; however, the latch arms  22 A, 22 B are elongated to a lesser degree. As is known with overcenter mechanisms, the latch arms  22 A, 22 B tend to be biased away from the first position of greatest elongation to either the second position of reduced elongation, or to a third position wherein the latch arms  22 A, 22 B are in the relaxed state. Thus, the latch assembly  18  secures and releases the cassette  16  with respect to the gear case  12  simply by pivoting the latch assembly  18  with respect to the gear case  12 , i.e., without the need of any additional tools or fasteners. By virtue of the grip  24  being spaced apart from the pivot points  20 A, 20 B a greater distance than the cam surfaces  26 A, 26 B are spaced apart from the pivot points  20 A, 20 B, a mechanical advantage is realized. 
     FIG. 4 shows the surface of the gear case  12  that interfaces with the cassette  16 . In a preferred embodiment of the present invention, a first clutch part, or clutch hub,  30  is driven by the driving source and is accessible from the exterior of the gear case  12 . The clutch hub  30  provides a driving force that is transferred through the cassette  16  to operate the implement  14 . Also projecting from the gear case  12  are positioning pins  32 A and  32 B for locating the cassette  16  with respect to the gear case  12 . As will be described further with reference to FIG. 5, the pins  32 A, 32 B are received in corresponding holes in the cassette&#39;s cover plate  40 . Although the pins  32 A and  32 B are shown as part of the gear case  12  and the holes are shown as part of the cassette  16 , the pins may alternatively be attached in the cassette  16 , and the holes formed in the gear case  12 . 
     FIG. 5 shows the surface of the cover plate  40  that interfaces with the gear case  12 . The pins  32 A, 32 B are matingly received in holes  34 A and  34 B, and the clutch hub  30  matingly engages a second clutch part, or drive spud,  72 ). 
     FIGS. 5 and 6 show a preferred embodiment of the present invention having a cassette  16  for connecting a reciprocating, double edge hedge trimming implement  14  to the gear case  12 . The cassette  16  includes a shell  38  and the cover plate  40 , and defines an interior volume. The shell  38  supports the mass of the implement  14  that is retained by means of two fasteners  42 A and  42 B and two nuts  48 A and  48 B secured to a clamping plate  46 , which is trapped between the shell  38  and the cover plate  40 . Anti-friction washers  44 A and  44 B are interposed between respective ones of the fasteners  42 A, 42 B and the blades  50 A, 50 B for improving the relative sliding action and reducing wear of the implement  14  with respect to the cassette  16 . Different clamping plates  46 , fasteners  42 A, 42 B, and nuts  48 A, 48 B may be used to support implements  14  having different characteristics within the housing  16 . 
     According to the preferred embodiment of the present invention, the implement  14  includes two stacked blades  50 A and  50 B that are longitudinally reciprocated with respect to one another. A blade support  52  extends along the length of the blades  50 A, 50 B to maintain the relative relationship between the blades  50 A, 50 B at the distal end thereof. The blades  50 A, 50 B and blade support  52  operate in a conventional manner. The blades  50 A, 50 B and the blade support  52  are interposed between the clamping plate  46  and the shell  38 , and extend outward from the interior of the cassette  16  through an opening between the shell  38  and the cover plate  40 . The relative configuration of the clamping plate  46  with respect to both the implement  14  and the cassette  16  ensures only the desired relative motion of the implement  14  with respect to the housing  16 . 
     Also mounted in the interior of the shell  38  is the drive spud  72  for matingly engaging the clutch hub  30  and for transferring motion from the clutch hub  30  to the blades  50 A, 50 B. According to the preferred embodiment of the present invention, the drive spud  72  engages a blade driver (not shown) that is rotates about the same axis of rotation as the clutch hub  30  and the drive spud  72 . The blade driver includes eccentrics (not shown) that matingly engage the blades  50 A, 50 B in a conventional manner for reciprocating the blades  50 A, 50 B with respect to one another. The drive spud  72  may also include a bearing  55  for reducing heat and wear. The drive spud  72 , clutch hub  30 , blade driver, and the eccentrics may all also be made of a material capable of acting as its own bearing surface. 
     The cover plate  40  includes the aperture  36  for the drive spud  72  to protrude from to engage the clutch hub  30 , as well as the holes  34 A, 34 B for receiving the positioning pins  32 A, 32 B. 
     When the cassette  16  is to be engaged with the gear case  12 , the pins  32 A, 32 B are aligned with the holes to prevent relative lateral movement between the cassette  16  and the gear case  12  The latch assembly  18  is subsequently pivoted to the second position described above to hold the cassette  16  against the gear case  12 . Concurrently, the drive spud  72  passes through the aperture  36  and matingly engages the clutch hub  30  for conveying movement from the driving source, through the cassette  16 , to the implement  14 . The reverse procedure is used for disconnecting the cassette  16  from the gear case  12 . 
     According the present invention, a common interface between cassette  16  and gear case  12  enables a wide range of implements  14  and main bodies  10  to be interchangeably connected. 
     According to another aspect of the present invention as shown in FIGS. 7 and 8, a bale handle  60  may be adjustably attached to the main body  10 . The adjustable bale handle  60  enables a user to hold the power tool  1  comfortably and safely after interchanging the implements  14  or after the user repositions themselves with respect to the workpiece. 
     According to a preferred embodiment of the present invention, the bale handle  60  is fastened to the main body  10  for pivotal movement about an axis. A detent system comprising at least one projection  62  and at least one recess  64  are matingly engageable for holding the bale handle  60  at a desired angular position with respect to the main body  10 . According to the preferred embodiment illustrated in FIGS. 7 and 8, the bale handle  60  includes a plurality of the projections  62 ′ and recesses  64 ′ arranged so as to at least partially circumscribe the pivot axis, and the main body  10  includes a plurality of the recesses  64 ″ (for engaging projections  62 ′) and projections  62 ″ (for engaging recesses  64 ′) arranged so as to at least partially circumscribe the pivot axis. For each position of the bale handle  60  relative to the main body  10 , at least one of the projections  62 ′, 62 ″ is matingly received in one of the recesses  64 ′, 64 ″, respectively. Elastically deforming the bale handle  60  so as to displace the projections  62  in a direction parallel to the axis and away from the recesses  64  enables the bale handle  60  to be angularly reoriented. Aligning and matingly engaging a different combination of the projections  62  with recesses  64  enables the bale handle  60  to be retained at a different angular position with respect to the main body  10 . 
     A lock may be used to releasably secure the detent system. According to a preferred embodiment, the lock may comprise cooperatively engaging threaded male and female members that, when relatively tightened, hold the projections  62  in the recesses  64 . 
     According to a preferred embodiment, the range of angular adjustment of the bale handle  60  with respect to the main body  10  is constrained by at least one stop  66  that extends axially from the main body  10  into at least one arcuate groove  68  in the bale handle  60 . The arcuate groove  68  partially circumscribes the pivot axis. The location and length of the arcuate groove  68  defines the permissible range of motion for the bale handle  60  relative to the main body  10 . 
     Although the projections  62  have been illustrated as being formed on the bale handle  60 , and the recesses  64  have been illustrated as being formed on the main body  10 , it is alternatively envisioned that the projections  62  may be formed on the main body  10  and the recesses  64  may be formed on the bale handle  60 . Similarly, although the stop  66  has been illustrated as being formed on the main body  10  and the arcuate groove  68  has been illustrated as being formed on the bale handle  60 , it is alternatively envisioned that the stop  66  may be formed on the bale handle  60  and the arcuate recess may be formed on the main body  10 . 
     FIGS. 9-15 are directed to a preferred embodiment of the present invention. According to this preferred embodiment, a driving force is transmitted through the clutch hub  30  and the drive spud  72 . The clutch hub  30  and the drive spud  72  are configured and arranged to cooperatively engage one another, thus facilitating transmission of the driving force from the main body  10  to the implement  14 . 
     The dimensions according to preferred embodiments of the present invention are indicated with on the Figures and correspond with the reference numerals in Table 1. 
     
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Ref. 
                   
                 Preferred 
                 Preferred 
               
               
                 No. 
                 Description 
                 Range 
                 Example 
               
               
                   
               
             
             
               
                 101 
                 Diameter of positioning pins 32A, 32B 
                 4-8 mm 
                 6.00 mm 
               
               
                 102 
                 Front to Back distance between gear center pin 70 
                 55-75 mm 
                 65.00 mm 
               
               
                   
                 and positioning pins 32A, 32B 
               
               
                 103 
                 Distance from center line between positioning 
                 25-35 mm 
                 30.25 mm 
               
               
                   
                 pins 32A, 32B to each of the positioning pins 
               
               
                   
                 32A, 32B 
               
               
                 104 
                 Distance between positioning pins 32A, 32B 
                 50-70 mm 
                 60.50 mm 
               
               
                 105 
                 Angle of drive tooth for clutch hub 30 
                 30-60° 
                 40° 
               
               
                 106 
                 Radius of drive tooth outside corner for clutch 
                 1-2 mm 
                  1.50 mm 
               
               
                   
                 hub 30 
               
               
                 107 
                 Radius of inside surface of drive tooth for clutch 
                 2-3 mm 
                  2.50 mm 
               
               
                   
                 hub 30 
               
               
                 108 
                 Diameter of center hole of clutch hub 30 
                 5-7 mm 
                  6.06 mm 
               
               
                 109 
                 Radius of drive tooth inside corner for clutch 
                 0.5-1.5 mm 
                  1.00 mm 
               
               
                   
                 hub 30 
               
               
                 110 
                 Angle between drive teeth for clutch hub 30 
                 30-60° 
                 45° 
               
               
                 111 
                 Diameter between drive teeth for clutch hub 30 
                 10-20 mm 
                 14.00 mm 
               
               
                 112 
                 Maximum distance of recess of drive teeth for 
                 25-35 mm 
                 29.00 mm 
               
               
                   
                 clutch hub 30 
               
               
                 113 
                 Vertical distance from end of gear center pin 70 
                 25-35 mm 
                 29.42 mm 
               
               
                   
                 to the locating ribs on the gear case 12 
               
               
                 114 
                 Horizontal distance from gear center pin 70 to the 
                 35-55 mm 
                 45.00 mm 
               
               
                   
                 rear locating ribs on the gear case 12 
               
               
                 115 
                 Horizontal distance from gear center pin 70 to the 
                 70-95 mm 
                 82.50 mm 
               
               
                   
                 front locating ribs on the gear case 12 
               
               
                 116 
                 Radius of arc that latch assembly 18 swings 
                 35-55 mm 
                 45.40 mm 
               
               
                   
                 through about pivot points 20A, 20B 
               
               
                 117 
                 Horizontal distance from pivot points 20A, 20B to 
                 30-50 mm 
                 37.10 mm 
               
               
                   
                 initial position of the arc for latch assembly 18 
               
               
                 118 
                 Vertical distance from pivot points 20A, 20B to 
                 20-35 mm 
                 26.15 mm 
               
               
                   
                 initial position of the arc for latch assembly 18 
               
               
                 119 
                 Horizontal distance from pivot points 20A, 20B to 
                 20-40 mm 
                 30.35 mm 
               
               
                   
                 final position of the arc for latch assembly 18 
               
               
                 120 
                 Vertical distance from pivot points 20A, 20B to 
                 25-40 mm 
                 33.76 mm 
               
               
                   
                 final position of the arc for latch assembly 18 
               
               
                 121 
                 Horizontal distance from gear center pin 70 to 
                  5-15 mm 
                 10.40 mm 
               
               
                   
                 pivot points 20A, 20B 
               
               
                 122 
                 Vertical distance from pivot points 20A, 20B to 
                 15-30 mm 
                 23.18 mm 
               
               
                   
                 locating ribs on gear case 12 
               
               
                 123 
                 Diameter of opening in gear case cover 
                 20-40 mm 
                 28.50 mm 
               
               
                 124 
                 Inside distance between latches 22A, 22B 
                  70-110 mm 
                 88.70 mm 
               
               
                 201 
                 Diameter of holes 34A, 34B 
                 4-8 mm 
                  6.00 mm 
               
               
                 202 
                 Front to back distance between centers of aperture 
                 50-80 mm 
                 65.00 mm 
               
               
                   
                 36 and holes 34A, 34B 
               
               
                 203 
                 Side to side distance from center of aperture 36 to 
                 25-35 mm 
                 30.25 mm 
               
               
                   
                 centers of holes 34A, 34B 
               
               
                 204 
                 Distance between centers of holes 34A, 34B 
                 50-70 mm 
                 60.50 mm 
               
               
                 205 
                 Angle of recess between drive teeth for drive spud 
                 30-60° 
                 50° 
               
               
                   
                 72 
               
               
                 206 
                 Angle of driven teeth for drive spud 72 
                 30-60 mm 
                 40° 
               
               
                 207 
                 Outside corner radius of driven teeth for drive 
                 1-2 mm 
                  1.50 mm 
               
               
                   
                 spud 72 
               
               
                 208 
                 Outside diameter of driven teeth for drive spud 72 
                 25-35 mm 
                 27.60 mm 
               
               
                 209 
                 Inside diameter of driven teeth for drive spud 72 
                  8-18 mm 
                 13.00 mm 
               
               
                 210 
                 Inside corner radius of driven teeth for drive spud 
                 0.5-1.5 mm 
                  1.00 mm 
               
               
                   
                 72 
               
               
                 211 
                 Vertical distance from cover plate 40 to bottom of 
                 25-45 mm 
                 34.84 mm 
               
               
                   
                 shell 38 at the gear center pin 70 location 
               
               
                 212 
                 Horizontal distance from center of drive spud 72 
                 40-65 mm 
                 53.20 mm 
               
               
                   
                 to back of cover plate 40 
               
               
                 213 
                 Horizontal distance from center of drive spud 72 
                  90-160 mm 
                 127.03 mm  
               
               
                   
                 to front of cover plate 40 
               
               
                 214 
                 Horizontal distance from center of drive spud 72 
                 30-50 mm 
                 41.00 mm 
               
               
                   
                 to sides of cover plate 40 at position of rear 
               
               
                   
                 locating ribs on the gear case 12 after assembly 
               
               
                 215 
                 Horizontal distance from center of drive spud 72 
                 30-50 mm 
                 41.30 mm 
               
               
                   
                 to sides of cover plate 40 at position of front 
               
               
                   
                 locating ribs one the gear case 12 after 
               
               
                   
                 assembly 
               
               
                 216 
                 Vertical distance from cover plate 40 to centers of 
                 10-20 mm 
                 14.00 mm 
               
               
                   
                 rollers 28A, 28B 
               
               
                 217 
                 Horizontal distance from center of drive spud 72 
                 20-40 mm 
                 29.00 mm 
               
               
                   
                 to centers of rollers 28A, 28B 
               
               
                 218 
                 Diameter of rolling surfaces of rollers 28A, 28B 
                 16-21 mm 
                 18.50 mm 
               
               
                 219 
                 Width of rolling surfaces of rollers 28A, 28B 
                 &gt;2 mm 
                  3.88 mm 
               
               
                 220 
                 Distance between rolling surfaces of rollers 28A 
                  80-110 mm 
                 93.02 mm 
               
               
                   
                 and 28B 
               
               
                   
               
             
          
         
       
     
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices, shown and described herein. Accordingly, various modifications may be made without departing from the spirit and scope of the general inventive concept as defined by the appended claims and their equivalents.