Abstract:
A tool for crimping work pieces to one another is disclosed. The tool is mounted on a power actuator having a reciprocating ram for effecting crimping. The tool includes a body engageable with the workpiece. A movable head is mounted on the body and receives the ram. A jaw is pivotably mounted on the body. A link connects the head to the jaw, which pivots in response to the ram engaging and moving the head. The jaw has a tooth that penetrates the work pieces upon pivoting of the jaw. Penetration of the work pieces by the tooth crimps the pieces to one another. A receiver is mounted on the body to permit its engagement with the actuator by means of an attachment device adapted to a particular actuator. The tool may be removably attachable to the actuator or permanently attached thereto.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention concerns a power tool for crimping two workpieces together.  
       BACKGROUND OF THE INVENTION  
       [0002]     During the installation of drywall, it is the practice to finish outside corners by affixing a metal angle piece along the corner from ceiling to floor. The angle piece covers and protects the edges of the drywall panels which are relatively brittle and subject to wear and damage by impact. The angle piece has a pair of elongate, thin gauge flanges which are joined lengthwise to form a bead at the vertex of the angle piece to provide increased stiffness.  
         [0003]     Once affixed in place, drywall compound is applied to feather the surface of the drywall panels at the corner, thereby presenting a neat appearance. It is preferred to affix the angle piece to the drywall by crimping the flanges into the drywall at a number of points along the length of the corner. Crimping is efficient as it avoids the need for fasteners. However, it is generally performed manually using a crimping tool and a hammer. In attaching the angle piece to the drywall, the crimping tool is held in contact with the angle piece which is positioned against the drywall with the flanges engaging the panels at the outside corner. The crimping tool has a pair of jaws which are arranged so that each one faces one of the flanges of the angle piece. Each jaw is pivotally mounted on the tool and has a tooth which will move into the flange and crimp it to the drywall when the jaw is pivoted. An impact head is mounted on the tool between the jaws. The impact head moves relatively to the tool when struck with the hammer. The jaws are mechanically linked to the head and will pivot in response to the head motion. Crimping of the angle to the drywall is effected when the hammer strikes the impact head, causing the jaws to pivot and forcing the teeth into the flanges and the drywall.  
         [0004]     Both the crimping tool and the hammer are heavy, and as multiple crimps must be made for each corner angle, it is apparent that such work will be fatiguing and may also result in repetitive motion injury. It is clear that efficiency and productivity would be improved and repetitive motion injury could be avoided by providing a power tool for crimping angle pieces to outside corners formed by drywall panels.  
       SUMMARY OF THE INVENTION  
       [0005]     The invention concerns a tool for crimping a first workpiece to a second workpiece positioned beneath the first workpiece. Specifically, the first workpiece may be a metal angle piece for drywall finishing and the second workpiece may be a pair of drywall panels forming an outside corner. The tool comprises a body having first and second contact surfaces engageable with the first workpiece. The contact surfaces are oriented at a right angle to one another to receive the outside corner formed by the drywall. A first jaw is pivotally mounted on the body adjacent to the first contact surface and a first tooth is mounted on the first jaw. The first tooth is movable in a direction facing outwardly from the first contact surface upon pivoting of the first jaw. A second jaw is pivotally mounted on the body adjacent to the second contact surface and a second tooth is mounted on the second jaw. The second tooth is movable in a direction facing outwardly from the second contact surface upon pivoting of the second jaw. An actuator having a movable ram is positioned proximate to the body. A head is movably mounted on the body. The head is engaged with the ram, and the ram effects motion of the head. A pair of links connect the jaws to the head. Each link has a first end pivotally attached to the head and a second end pivotally attached to a respective jaw. Crimping of the angle piece to the drywall is effected by the actuator powered ram moving the head, the links causing pivoting of the jaws in response to the head motion, the teeth being thereby forced into the flanges and the drywall. The actuator may be powered by any practical means, such as electrically or pneumatically. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a partial side view of a power crimping tool according to the invention;  
         [0007]      FIG. 1A  is a partial side view of the power crimping tool shown in  FIG. 1  engaging a workpiece;  
         [0008]      FIG. 2  is a perspective view of a portion of the crimping tool shown in  FIG. 1  engaging a workpiece;  
         [0009]      FIG. 3  is a front view of the power crimping tool engaging a workpiece;  
         [0010]      FIG. 3A  is a partial view on an enlarged scale taken at circle  3 A in  FIG. 3 ;  
         [0011]      FIG. 4  is a front view of the power crimping tool engaging a workpiece;  
         [0012]      FIG. 4A  is a partial view on an enlarged scale taken at circle  4 A in  FIG. 4 ;  
         [0013]      FIG. 5  is a sectional view taken at line  5 - 5  in  FIG. 1A ;  
         [0014]      FIG. 6  is a partial side view of another embodiment of a power crimping tool according to the invention; and  
         [0015]      FIG. 6A  is a partial side view of the power crimping tool shown in  FIG. 6  engaging a workpiece. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0016]      FIG. 1  shows a power crimping tool  10  according to the invention. Tool  10  comprises an actuator  12 , which is preferably electrically powered but may also be powered by other practical means such as pneumatically. A ram  14  is attached to the actuator  12 , the ram being movable in reciprocating motion by the actuator. A handle  16  is attached to the actuator  12  to allow the tool to be manually gripped. A trigger  18  is mounted on the handle  16 . When the tool  10  is armed (described below) and the trigger is manually depressed, the actuator  12  is caused to drive the ram  14  in a single cycle of reciprocal motion, outwardly from and then back toward the actuator.  
         [0017]     A crimping mechanism  20  is attached to the handle  16  adjacent to actuator  12 . Crimping mechanism  20  is preferably releasably attached to handle  16  as described in detail below, thereby allowing the actuator  12  to be used in conjunction with appropriate attachments for functions other than crimping, such as driving nails. As best shown in  FIGS. 2 and 3 , crimping mechanism  20  comprises a body  22  having contact surfaces  24  and  26 . The contact surfaces are oriented at a right angle to one another so as to advantageously engage an angle piece  28  to be crimped. The contact surfaces  24  and  26  are separated by a groove  30  which runs lengthwise along the body to receive a bead  32  formed at the vertex of the angle piece  28 .  
         [0018]     As shown in  FIG. 2 , a receiver  34  is positioned on body  22  opposite contact surfaces  24  and  26 . Receiver  34  is preferably a channel  36  defined by a pair of flanges  38  positioned in spaced relation so as to receive the handle  16  as shown in dotted line in  FIG. 1A . With reference again to  FIG. 2 , an attachment device  40  extends from the receiver  34  to engage handle  16 . Attachment device  40  preferably comprises a pair of mounting brackets  41  having slots  43  which receive bolts  42 . Bolts  42  are retained within the slots by nuts  44 . Bolts  42  engage holes through the handle  16  (not shown) and releasably attach the body  22  to the handle as illustrated in  FIGS. 1 and 1 A. The body  22  is easily removable from the handle  16  by removing the bolts  42 . The body  22  is also slidable toward and away from the actuator  12 , the slots  43  allowing relative motion between the body  22  and the handle  16  when the tool  10  engages a workpiece as shown by a comparison of  FIGS. 1 and 1 A.  
         [0019]     As best shown in  FIG. 3 , jaws  46  and  48  are mounted on body  22 , one jaw adjacent to each contact surface  24  and  26  respectively. Jaws  46  and  48  pivot about respective pivot axes  50  and  52 . Jaw  46  has a tooth  54  mounted eccentric to the pivot axis  50 , and jaw  48  has a tooth  56  mounted eccentric to the pivot axis  52 . Eccentric positioning of the teeth  54  and  56  allow them to extend outwardly from the respective contact surfaces  24  and  26  to crimp the angle piece  28  to another workpiece, such as drywall panels  58  and  60 , when the jaws  46  and  48  are pivoted about their respective pivot axes  50  and  52 . This operation is described in more detail below.  
         [0020]     As shown in  FIGS. 2 and 3 , a post  62  is mounted on body  22  between jaws  46  and  48 . Post  62  extends in a direction away from the contact surfaces  24  and  26 . A head  64  is slidably mounted on post  62 , the head being guided by the post in reciprocal motion toward and away from the contact surfaces  24  and  26 . Preferably, a biasing device in the form of a coil spring  66  is positioned between the head  64  and post  62  and biases the head away from the post. As shown in  FIG. 3 , a link  68  extends from head  64  to jaw  46 . One end  68   a  of the link  68  is pivotally mounted to the head  64  and the opposite end  68   b  is pivotally mounted to the jaw  46  in spaced relation to the jaw&#39;s pivot axis  50 . A similar link  70  extends between head  64  and jaw  48 , the ends  70   a  and  70   b  of the link  70  being pivotally attached to the head  64  and the jaw  48  respectively.  
         [0021]     As shown in  FIGS. 2 and 5 , an impact surface  72  is positioned on a flange  74  extending outwardly from head  64 . The impact surface  72  receives the force of the ram  14  and is preferably a sacrificial surface which is removable and replaceable as it wears out. During the course of its reciprocal motion, as depicted by a comparison of  FIGS. 3 and 4 , ram  14  engages impact surface  72  and forces head  64  to move against the biasing force of spring  66  toward the contact surfaces  24  and  26 . Motion of the head  64  is transmitted by links  68  and  70  to jaws  46  and  48  respectively. The jaws are caused to pivot substantially simultaneously and the teeth  54  and  56  on each jaw extend outwardly from contact surfaces  24  and  26  and engage and crimp the angle piece  28  to the drywall panels  58  and  60 . Motion of jaw  48  is shown in detail in  FIGS. 3A and 4A , the motion of jaw  46  being substantially similar.  
         [0022]     As shown in  FIG. 1 , supplemental contact surfaces  76  and  78  are mounted onto handle  16  in spaced relation to body  22 . Supplemental contact surfaces are preferably releasably mounted to handle  16  using bolts  80 . As shown in  FIG. 2 , the supplemental contact surfaces  76  and  78  align with the aforementioned contact surfaces  24  and  26  when tool  10  engages the angle piece  28 , the supplemental contact surfaces  78  and  78  supporting and aligning the tool when in use.  
         [0023]     As shown in  FIG. 1 , tool  10  is prepared for use by mounting the body  22  and the supplemental contact surfaces  76  and  78  onto the handle  16 , the body being mounted by bolts  42  extending through handle  16  and engaging slots  43  in mounting brackets  41 . The bolts are retained by nuts  44 .  
         [0024]     Operation of tool  10  is described below with reference to  FIGS. 1, 1A ,  3  and  4 . With reference to  FIG. 3 , the angle piece  28 , comprising a first workpiece, is positioned overlying an outside corner formed by drywall panels  58  and  60  which constitute a second workpiece. Contact surfaces  24  and  26  are placed in engagement with the angle piece  28 , substantially aligning the tool  10  with the outside corner. Handle  16  is pushed toward the workpieces  28 ,  58  and  60  causing the handle  16  to slide relatively to the body  22  until the supplemental contact surfaces  76  and  78  engage the angle piece  28 . As shown in  FIGS. 1A and 3 , mounting brackets  41  enter actuator  12  through access ports  49  and engage a switch (not shown) positioned within the actuator which arms the tool  10 . When the tool is armed electrical power is made available to the actuator, the power being controlled by trigger  18 . This is a safety feature which allows the tool to operate only when the body  22  is properly engaged with a workpiece, such as angle piece  28 .  
         [0025]     When trigger  18  is pulled while the tool is armed it causes actuator  12  to cycle ram  14  through a single reciprocal stroke. As shown in  FIG. 1A , the ram  14  engages the impact surface  72 , forcing the head  64  toward the contact surfaces  24  and  26 . Motion of ram  14  and head  64  is indicated in  FIG. 4  by arrows  82 . Links  68  and  70  transmit the motion of head  64  to the jaws  46  and  48 , causing them to pivot about respective axes  50  and  52 . Pivoting motion of the jaws causes the teeth  54  and  56  on each jaw to extend outwardly from contact surfaces  24  and  26  respectively and crimp the first workpiece (angle piece  28 ) to the second workpiece (drywall panels  58  and  60 ). Ram  14  retreats from engagement with impact surface  72  during the course of its motion and the head  64  is pushed back away from the contact surfaces  24  and  26  by the biasing spring  66 . Again, links  68  and  70  transmit the motion of the head  64  to the jaws  46  and  48  which pivot in the opposite direction and draw teeth  54  and  56  back to a position recessed beneath the contact surfaces  24  and  26 . The tool  10  is then repositioned along the angle piece  28 , armed by moving the handle  16  relatively to body  22  so that mounting brackets  41  close the arming switch, and the trigger is pressed again to form another crimp. This procedure is repeated until the angle piece  28  is secured to drywall panels  58  and  60 .  
         [0026]     The configuration of power crimping tool  10  shown in  FIGS. 1 and 1 A is provided by way of example only and may be modified to suit a particular actuator design  12  and still remain within the scope of the invention. Actuators from various manufacturers will differ in design details and the crimping mechanism  20  is readily adaptable to fit any design. By way of example, an alternate embodiment of the tool  90  from a different manufacturer than tool  10  and having a different design is illustrated in  FIGS. 6 and 6 A. Tool  90  has substantially the same components as tool  10  and operates substantially as described above but, being supplied by a different manufacturer, will have an actuator  92  that has a different internal layout. This may, for example, require that body  22  of crimping mechanism  20  be mounted onto the actuator  92  differently from the mounting used with actuator  12 . To this end, as shown in  FIG. 6 , a mounting bracket  94  is used to slidably mount body  22  onto the actuator  92 . Bracket  94  is designed to comply with the particular design and operation of actuator  92  and comprises a first end  96  attached to the front end of body  22  adjacent to jaws  46  (not shown) and  48 . An opposite end  98  is attached to the actuator  92 , for example, by screws  100  which are adapted to engage an existing nose piece assembly  102  that would otherwise be engaged by a lockout probe (not shown) used when the actuator performs a different function, such as for a nail driving gun. Screws  100  are received within an elongated slot  104  that extends lengthwise along bracket  94  thus allowing the bracket to slide relatively to actuator  92  and permit the body  22  to move toward and away from the actuator. Sliding motion of the body  22  is effected when it engages a workpiece  28  as shown by a comparison of  FIGS. 6 and 6 A. The motion of the bracket end  98  within the actuator  92  allows body  22  to move to a position as shown in  FIG. 6A  wherein ram  14  can engage impact surface  72  and effect the crimping function. Bracket end  98  is also used to trip a switch (not shown) within the actuator  92  that arms the tool  90  and allows trigger  18  to control the crimping operation as described previously.  
         [0027]     Although tool  10  is described above as having modular components which are assembled onto an actuator/handle unit, it is also feasible that the tool be dedicated only to the crimping function, in which case the crimping mechanism  20  and the supplemental contact surfaces  76  and  78  would be permanently attached to handle  16 . Furthermore, when the tool is a multi-purpose tool, there may be other safety features applicable to one function but not relevant to another function of the tool which must be overridden to arm the tool. For example, when the tool is used to drive nails, it usually will not function unless there are nails loaded in the tool. When such a tool is converted to a crimping function, although the nails are no longer relevant, the safety feature requiring nails to be loaded in the tool is still operative. This safety feature may be overridden by providing a mode switch on the handle which eliminates the need for nails to be loaded by closing the circuit which would otherwise be closed when nails are loaded in the tool. Alternatively, the components, such as the body  22  may also trigger an override switch when mounted on the handle  16  which eliminates the need for nails loaded in the tool when a crimping function is being performed.  
         [0028]     Power crimping tools according to the invention will increase productivity, provide uniformity of crimping action and reduce the possibility of injury due to repetitive motion.