Abstract:
A crimping tool is provided including a rotary drive unit and removable extension arm with pivotal jaw arms. The removable extension arm is rotatable about its axis. A locking device is included in the jaw arm assembly such that the jaw arms may be securely positioned in a number of locations to accommodate various working angles. A logic circuit limits the movement of the jaw arms to one complete cycle for each trigger event.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to hand tools, and more particularly to a power tool for crimping steel studs and tracks during construction framing. 
     BACKGROUND 
     Steel framing has become increasingly popular for residential and commercial buildings due to the increased strength and termite resistance of steel relative to wood. However, the process of assembling steel framing is time consuming and expensive relative to the material costs. As a result of these increased labor costs, steel framing has been slow to achieve wide-spread acceptance. 
     Presently steel studs and tracks are assembled either vertically or horizontally with each of the studs screwed to the track. In horizontally constructed walls, the studs and tracks are positioned on the floor relative to one another and screws are placed in one side of each track to secure each stud to the track. The wall is then flipped over and screws are inserted into the other side of each track. In vertically constructed walls, the laborer must work on each side of the wall to screw the studs into the tracks on the top and bottom of the wall. The top is difficult to reach and the bottom requires that the operator bend or kneel on the floor. 
     Crimping tools have also been utilized to connect the studs to the tracks. However, manual crimping tools require a lot of strength and endurance to operate on large jobs and power crimping tools have proven to be heavy and cumbersome. The inefficiency of prior methods for assembling steel studs to the tracks has contributed greatly to the labor costs for steel frame construction. 
     Given the aforementioned drawbacks, it is desirable to provide a power crimping tool that alleviates much of the labor costs associated with steel framing 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a hand-held crimping tool that can be properly aligned while providing the user with a broad range of workable engagement angles. 
     It is another object of the present invention to provide a rotary drive tool with a releasably attached extension arm that is rotatable about its axis. 
     It is still another object of the present invention to provide a jaw arm assembly that is pivotally attached to the extension arm. 
     It is a further object of the present invention to provide a crimping tool that achieves one complete crimp cycle for every trigger activation. 
     It is yet another object of the present invention to provide a hand-held crimping tool that has a self-contained power source. 
     In order to obtain these and other objects, the present invention provides a crimping tool including a rotary drive unit and an extension arm. The extension arm includes a pivotally attached jaw assembly attached thereto. Upon activation of the rotary drive tool, the gear configuration in the extension arm translates a rotary input into actuation of the jaw assembly. The jaw assembly includes a first piercing jaw arm and a second receiving jaw arm for cyclical engagement therewith. A logic circuit limits an activation to one complete crimping cycle of the jaw assembly. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a side view of the crimping apparatus constructed in accordance with the teachings of the preferred embodiment of the present invention shown with the extension arm located in the center position. 
     FIG. 2 is a side view of the extension arm and jaw assembly shown with the barrel rotated 90 degrees from the rotary drive tool. 
     FIG. 3 is a rear view of the extension arm removed from the tool for purposes of illustrating the conical cam configuration. 
     FIG. 4 is a cross-sectional view of the jaw assembly taken along line  4 — 4  of FIG.  3 . 
     FIG. 5 is cross-sectional view of the jaw assembly taken along line  5 — 5  of FIG.  4 . 
     FIG. 6 is a cross sectional view of the jaw assembly taken along line  6 — 6  of FIG.  4 . 
     FIG. 7 is a cutaway view of the jaw assembly with half of the housing cutaway for illustrative purposes. 
     FIG. 8 is a bottom view of the jaw assembly with the housing removed. 
     FIG. 9 is a cutaway perspective view of the jaw assembly with part of the housing cutaway to illustrate the transmission. 
     FIG. 10 is a perspective view of the transmission and jaw assembly with the lower jaw removed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As is most clearly illustrated in FIG. 1, the crimp tool  10  of the present invention generally includes a rotary drive tool  12  and a crimp attachment  14 . The rotary drive tool  12  includes an output shaft (not specifically shown) that is coupled to a rotary shaft  16  (FIG. 9) with a connecting device carried in an extension barrel  20  which also houses a transmission  18  (best shown in FIG.  4 ). Power source  24  interconnects to drive tool  12 . The barrel  20  is rotatable about its longitudinal axis and a jaw assembly  19  is coupled to the barrel  20  for pivotal movement relative thereto. The transmission  18  transfers the rotary motion of the rotary shaft  16  to articulate the jaws as hereinafter described. 
     As is most clearly illustrated in FIGS. 1 and 2, the jaw assembly  19  is coupled to pivot relative to the barrel  20  by a pivot shaft  26  to allow the laborer to move the jaw assembly  19  to a proper position prior to crimping. By allowing the barrel  20  to rotate about its longitudinal axis and the jaw assembly  19  to pivot about shaft  26 , the crimp tool  10  permits the laborer to position the jaw assembly  19  to crimp both sides of the stud/track from the same side of the wall. 
     With reference to FIGS. 4-10, the transmission  18  operatively couples the jaw assembly  19  to the rotary shaft  16  such that rotation of the shaft  16  causes pivotable movement of an upper jaw  28  about a pivot pin  30  fixed to a lower jaw  32 . Rivet  81  holds the members that comprise the upper jaw arm  28  together and rivet  82  holds the members of the lower jaw arm  32  together. Accordingly, movement of the upper jaw  28  from its open position to its closed position causes a piercing bit  33  to deform the stud and frame thereby crimping the two members together. The surface of the lower jaw  32  that accommodates the piercing bit  33  may be configured to fold over the resulting burr thereby limiting the distance that the burr protrudes from the stud or track. 
     Referring now to FIGS. 4-6, transmission  18  includes a cam  34  fixed for rotation with rotary shaft  16 , a rocker arm  36  having a first end  44  engaged with cam  34  and a second end  45  fixed to rotate with shaft  26 . A counterweight  87  extends from shaft  16  to encourage smooth operation. The first end  44  includes a bearing  49  which acts as a cam follower to cam  34 . Cam  34  is configured to have an eccentric surface  35  to engage bearing  49  in a common plane while rocker arm  36  rotates. A drive cam  40  is coupled to the shaft  26  by a roller clutch  38  (FIG.  6 ). The upper jaw  28  includes a cam follower  42  that engages drive cam  40  to displace the upper jaw  28  between its open and closed positions in response to rotation of the drive cam  40 . As rotary shaft  16  rotates cam  34 , the eccentric surface  35  of the cam  34  oscillates the first end  44  of the rocker arm  36  in pivoting motion about the axis  46  of shaft  26 . More particularly, the riding engagement between the first end  44  of the rocker arm  36  and the rotating cam  34  causes cyclical displacement of the rocker arm  36  at a magnitude of 15 degrees for each full rotation of the cam. The rocker arm  36  is biased toward cam  34  by a spring  58  (FIG. 9) to influence contact thereto. Spring  58  is supported on one end by finger  56  extending from rocker arm  36  and on the other end by protruded housing portion  22  (FIG. 1) of crimp attachment  14 . The shaft  26  is fixed to, and cycles with, the rocker arm  36 . This incremental rotation is transferred to the drive cam  40  by the one-way roller clutch  38  so as to index the drive cam  40  to rotate in the direction of arrow  48  (clockwise). Specifically, the one way roller clutch  38  couples the drive cam  40  to the shaft  26  such that the drive cam  40  rotates clockwise with the shaft  26  while allowing the shaft  26  to rotate relative to the drive cam  40  when the shaft  26  rotates in the counterclockwise direction. 
     The drive cam  40  includes an outer cam surface  50  upon which the cam follower  42  rides. The outer cam surface  50  defines a lift angle that radially diverges from axis  46  in the direction of arrow  48 . Thus, rotation of the drive cam  40  radially displaces the cam follower  42  thereby causing the upper jaw  28  to pivot about pin  30  from its open position toward its closed position. The drive cam  40  includes a recess  54  within which the cam follower  42  falls to return the upper jaw  28  to its open position. 
     In addition to the piercing movement of the upper jaw  28 , the present invention allows for the position of the jaws to be adjustable through rotation of the barrel  20  or articulation of the jaw assembly  19  about shaft  26 . 
     The crimp tool can optionally include a lock assembly  25  for fixing the position of the jaws prior to the crimping operation. As is best illustrated in FIG. 6, the lock assembly  25  includes a locking plate  60  that is movable within the barrel housing  62  from an engaged position to a disengaged position against the bias of a spring  64 . The plate  60  includes locking tabs  66  configured to engage cooperatively configured locking apertures  68  formed in the lower jaw  32  to fix the lower jaw  32  to the barrel housing  62 . To change the angular orientation of the jaw assembly  19  relative to the barrel housing  62 , the laborer can place the locking plate  60  in its disengaged position by axially displacing the shaft  26  toward locking plate  60  thereby moving the tabs  66  from engagement with the lower jaw  32 . The locking plate  60  can include a plurality of peripherally spaced locking apertures  68  to permit the user to fix the lower jaw  32  in a variety of positions relative to the barrel housing  62 . 
     A logic circuit  51  is included that limits the movement of the jaw assembly  19  to one cycle with each activation of the trigger  21 . One cycle is defined as the movement of the jaw assembly  19  from a fully open position, to a fully closed (crimping) position and back to a fully open position. The logic circuit  51  may be configured such that the position sensor  52  is disposed on the drive cam  40  and the receiver  55  is disposed on the cam follower  42  (FIG.  9 ). In an alternative embodiment, the logic circuit  51  includes a position sensor  52  disposed on shaft  16  interconnected to a receiver  55  (not specifically shown). The logic circuit  51  regulates the movement of the shaft  16  to the appropriate number of revolutions (24 for the embodiment disclosed) such that one complete cycle of the jaw assembly  19  is achieved. Once one complete cycle is realized, the logic circuit  51  stops the output of the rotary drive tool  12  thereby causing the jaw assembly to remain in its fully open position able to readily accept the members for the next crimp event. In an alternative configuration, a sensor is mounted to one of the jaw arms and a magnet is disposed on the other jaw arm. (*** Inventors please confirm the accuracy of these descriptions) The movement of the jaw assembly  19  would be limited to the cam rotation realized by the logic circuit  51  accordingly. It is understood however, that the logic circuit configuration described herein may be employed in alternative ways. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.