Abstract:
An apparatus for imparting a predetermined profile to one end of a workpiece mounted on a main axis. The apparatus comprises a rotary head mounted for rotation about the main axis and at least two fingers pivotally mounted to the rotary head for pivotal movement between an open position and a closed position. Each finger has a shaping tool adapted to engage the workpiece, and a cam mounted between said at least two fingers in riding contact with an inwardly facing cam surface thereof to pivot the fingers between said open and closed positions upon relative axial movement between the rotary head and the cam.

Description:
TECHNICAL FIELD  
       [0001]     The invention relates generally to a swaging head assembly for performing a shaping or forming operation at one end portion of a workpiece.  
       BACKGROUND OF THE ART  
       [0002]     Over the years various apparatuses have been developed for performing swaging operation on workpiece. Such swaging apparatuses generally comprises a rotary head carrying a number of forming rollers press in rolling contact with the workpiece to be profiled while the rotary head is driven in rotation.  
         [0003]     Known swaging apparatuses are not well suited for high speed operations and include rather complex and cumbersome roller actuating mechanisms.  
       SUMMARY OF THE INVENTION  
       [0004]     It is therefore an object of this invention to provide a new swaging head assembly which addresses the above mentioned problems.  
         [0005]     In one aspect, the present invention provides a swaging head assembly for performing a shaping operation at one end of a workpiece mounted on a main axis, the swaging head assembly comprising: a rotary head member rotatable about the main axis, at least two pivotal fingers pivotally mounted at an intermediate location between opposed first and second ends thereof to the rotary head member, each pivotal finger carrying a shaping roller adapted to be engaged in rolling contact with the workpiece, and a cam mounted inwardly of said at least two fingers for pivoting the fingers between an open position and a closed position as a result of a relative axial displacement between the rotary head member and the cam.  
         [0006]     In another aspect, the present invention provides an apparatus for imparting a predetermined profile to one end portion of a workpiece mounted on a main axis, the apparatus comprising a rotary head mounted for rotation about the main axis, at least two fingers pivotally mounted to the rotary head for pivotal movement between an open position and a closed position, each finger having a shaping tool adapted to engage the workpiece, and a cam mounted between said at least two fingers in riding contact with an inwardly facing cam surface thereof to pivot the fingers between said open and closed positions upon relative axial movement between the rotary head and the cam.  
         [0007]     In another aspect, the present invention provides a swaging head assembly for producing an annular groove in one end portion of a workpiece mounted on a main axis, the apparatus comprising a rotary head mounted for rotation about the main axis, said rotary head being movable axially towards and away from the workpiece along said main axis, at least two fingers pivotally mounted to the rotary head, each finger having first and second opposed ends and an intermediate point of pivot therebetween, said first end having a cam surface on an inwardly facing side thereof, each finger carrying a groove forming roller at said second end thereof, said groove forming rollers being adapted to engage the workpiece when the fingers are closed against the one end portion of the workpiece, and a cam mounted internally of said rotary head between said first end of said at least two fingers for engagement with said cam surface thereof to pivot said fingers about said intermediate point of pivots between said open and closed positions upon relative axial movement between the rotary head and the cam.  
         [0008]     Further details of these and other aspects of the present invention will be apparent from the detailed description and figures included below. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0009]     Reference is now made to the accompanying figures depicting aspects of the present invention, in which:  
         [0010]      FIGS. 1   a ,  1   b ,  1   c ,  1   d  and  1   e  are schematic elevation views illustrating the sequence of the operations on a workpiece using a swaging head according to an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]      FIG. 1   a  illustrates a swaging head assembly  10  in a retracted position thereof before swaging a cylindrical workpiece W held thereunder in position by a fixture or any appropriate positioning system (not shown). The workpiece W (in the illustrated assembly a cylindrical lipstick container) is axially aligned with the central rotary axis  12  of the swaging head assembly  10 . The swaging head assembly  10  is driven in rotation about axis  12  by a driving source (not shown), such as an electric motor.  
         [0012]     The swaging head assembly  10  generally comprises a rotary head member  14  carrying a number of downwardly depending fingers  16  (three in the illustrated embodiment). The fingers  16  are uniformly distributed about the rotary head member  14  and are pivotally mounted thereto at  18 . The pivots  18  are located at an intermediate location between the opposed longitudinal ends of the fingers  16 .  
         [0013]     Each finger  16  carries at a lower end thereof a shaping or forming tool, such as a roller  20  having a rotary axis  22  collinear with the longitudinal axis of the associated finger  16 . The rollers  20  are preferably mounted for free rotation on needle bearings (not shown). A circumferential ridge  24  is provided on the outer surface of each roller  20  to form a circumferential groove  26  ( FIGS. 1   c ,  1   d  and  1   e ) in the outer surface of the workpiece W at a predetermined distance D ( FIG. 1   e ) from the upper end thereof  28 . It is understood that the outer surface of the rollers  20  can have various shapes and configurations depending on the desired profile to be given to the upper end of the workpiece W.  
         [0014]     The fingers  16  are pivoted between an open position ( FIGS. 1   a ,  1   b ,  1   d  and  1   e ) and a closed position ( FIG. 1   c ) by a cam  30 . It has been found that mounting the cam  30  internally of the rotary head member  14  between the pivotal fingers  16  as opposed to externally with respect thereto greatly simplifies the overall assembly of the swaging head assembly  10 . The cam  30  is received in a central seat  32  ( FIG. 1   c ) defined in the bottom surface of the head member  14 . The cam  30  has a generally frustoconical shape and is in sliding contact with a corresponding cam surface  34  provided on an inner side of the upper end of the fingers  16 . The cam surface  34  has a tapered portion converging towards the axis  12  in a direction towards the workpiece W. The distance between the cam surface  34  and the point of pivot  18  of the fingers  16  provides a mechanical leverage allowing the rollers  20  to be closed against the workpiece with sufficient force to impart the desired profile to the workpiece W with little effort imparted onto the actuating end (i.e. the end with the cam surface  34 ) of the fingers  16 . The configuration of the fingers  16  with the actuating portion at one end, the tool shaping portion at the other end and the intermediate point of pivot therebetween is thus advantageous.  
         [0015]     Springs  35  are provided outwardly of the fingers  16  at the upper actuating end thereof to normally bias the fingers  16  to an open position as shown in  FIGS. 1   a ,  1   b ,  1   d  and  1   e.    
         [0016]     The cam  30  is mounted at the distal end of a reciprocating shaft  36  coaxial with axis  12 . The shaft  36  is actuated by any appropriate actuator (not shown), such as a pneumatic or hydraulic cylinder or a screw motor. The actuator (not shown) is operational to axially displace the cam  30  relatively to the rotary head member  14  and, thus, the fingers  16 . According to another embodiment of the present invention, the cam  30  could be axially stationary while the rotary head  14  is axially displaced to create the required relative axial movement between the cam  30  and the fingers  16  to thereby allow the fingers  16  to open and closed under the action of the cam  30 . According to this embodiment however the orientation of the cam  30  and the cam surface  34  would be turned upside down (i.e. the cam  30  would taper in an upward direction and the cam surface  34  would converge towards the axis  12  in an upward direction away from the workpiece W).  
         [0017]     The reciprocating shaft  36  is coaxially received for axial movement in a hollow driving shaft  38  operated by a linear actuator (not shown) for lowering and raising the rotary head member  14 .  
         [0018]     A localization or positioning aid such as in the form of an abutting surface  40  is provided on the rotary head member  14  centrally between the fingers  16  at a predetermined distance from the shaping ridge  24  of the rollers  20 ; this predetermined distance corresponding to the desired distance D ( FIG. 1   e ) between the end  28  of the workpiece W and the groove  26  to be formed. As shown in  FIGS. 1   b  and  1   c , the abutting surface  40  is shaped and configured to uniformly abut against the upper end  28  of the workpiece W to ensure that groove  26  be repeatedly and consistently formed at the same distance from the end  28  of each workpiece W being processed. The fixture (not shown) holding the workpiece W is preferably axially spring loaded to compensate for differences in length and height positioning between the different workpiece to be processed.  
         [0019]     In operation, the rotary head member  14  is lowered over the workpiece W to be grooved until the abutting surface  40  abuts against the top end  28  of the workpiece, as shown in  FIG. 1   b . During this lowering phase, the cam  30  is retracted and the fingers  16  are urged to their open position by the springs  35 . Once the rotary head member  14  has been appropriately position relative to the workpiece W, the cam  30  is displaced axially downwardly to cause the fingers to pivot to a closed position against the biasing force of the springs  35 . As shown in  FIG. 1   c , in their closed position, the rollers  20  are firmly pressed against the outer surface of the workpiece W. The swaging head assembly  10  is then driven in rotation about axis  12  to cause the rollers  20  to roll over the workpiece W and thereby formed the circumferential groove  26 . Once the grooving operation is completed, the cam  30  is retracted to allow the arm to pivot back to their open position under the biasing action of the springs  35 , as shown in  FIG. 1   d . Finally, the rotary head member  14  is raised away from the workpiece W back to its retracted position, as shown in  FIG. 1   e . Then, a new workpiece W is mounted on the axis  12  underneath the swaging head assembly  10  and the above-described process is repeated all over again.  
         [0020]     The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without department from the scope of the invention disclosed. For example, it is understood that the above described vertical orientation of the apparatus is exemplary only and that the apparatus could be oriented otherwise. It is also understood that the workpiece W could be axially displaced between the fingers  16  in abutment against the abutting surface  40  while the rotary head member  14  remains in a fixed axial position. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.