Abstract:
A progressive forming machine having a frame supporting a plurality of workstations uniformly spaced in a horizontal plane, a transfer mechanism for shifting parts from one station to another and from a last station to a discharge station, a conveyor in the frame for lowering parts from the transfer discharge station, the conveyor having individual part carriers, the conveyor being arranged to present a carrier beneath the discharge station in timed relation to the operating cycle of the machine.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a device for conveying formed parts made in a progressive forging machine from a level of the work stations to a lower level for removal from the machine. 
     PRIOR ART 
     Progressive cold forming machines typically have several workstations spaced along a horizontal plane and a valley below the plane into which scrap trimmed and punched from a workpiece falls for collection to a gravity chute. The finish formed workpiece or part also is customarily dropped into the valley area from a discharge position of a part transfer mechanism. Formed parts can be damaged in the machine when a part freefalls from the transfer discharge and strikes a preceding part or the rigid gravity discharge chute itself. The potential for damage to a formed part involves many factors including its configuration, mass, and hardness. 
     One attempt to avoid the risk of damage from parts dropping on one another has been to convey them individually along a horizontal path just below the workstation plane. This arrangement has the disadvantage of obstructing the tool area by eliminating a convenient platform height that an operator could otherwise stand on. Moreover, this approach can require a hole to be provided in the sidewall of the machine frame or bed, thereby weakening the sidewall. 
     SUMMARY OF THE INVENTION 
     The invention provides a generally vertically oriented conveyor in the interior of a forming machine. The conveyor receives individual finish formed parts at a transfer discharge point and lowers the part at a controlled rate of descent thereby preventing collision damage between parts in a discharge path from the machine. 
     The disclosed conveyor includes a pair of endless chains that vertically transport carriers that in the illustrated case are of a pan-like configuration. At one stretch or side, the chains move the carriers from the transfer area to a lower elevation within the machine where the parts are discharged at a low freefall velocity thereby eliminating or reducing a risk of damage from impacts with other finish form parts of the rigid gravity discharge chute. 
     The invention, by enabling the parts to be mechanically lowered within the machine, avoids obstruction of an area adjacent the plane of the workstations used by an operator to service the machine. Moreover, the inventive conveyor does not require a modification of the machine frame which could compromise its rigidity and/or strength. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional elevational view of a progressive former within which is mounted a down conveyor of the invention; 
         FIG. 2  is a diagrammatic perspective view of the down conveyor taken from the down side; 
         FIGS. 3A-3F  are successive diagrammatic views of a carrier as it moves laterally under and then downwardly under an outboard discharge position of the fingers of a transfer mechanism; and 
         FIG. 4  is a diagrammatic perspective view of an upper end of the down conveyor taken from the up-side. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  illustrates the cross-sectional profile of a multi-station progressive cold forming machine  10 . As is customary, metal parts or workpieces are progressively transferred to successive workstations  11  after being worked by opposed tools at preceding stations. Typically, this movement of the workpieces is accomplished with a transfer mechanism having depending fingers  12 . The transfer fingers  12  grip a workpiece at a workstation  11  and in timed relation to the operation of the machine  10  shifts it to the next succeeding workstation  11 . 
     A conveyor  16  includes two endless roller chain loops  17 ,  18 . One chain  17  is in a vertical plane adjacent the transfer fingers  12  and a bolster  19  while the other chain  18  is displaced from the bolster. The chains  17 ,  18  are trained over respective upper and lower sprockets or wheels  21 ,  22 . An outboard upper sprocket  21  is fixed on a drive shaft  23  rotatably supported in bearings mounted in a conveyor frame  24 . The lower sprockets  22  are fixed on a common shaft  25  rotatably supported in a lower part of the frame  24 . The outboard upper sprocket  21  drives the co-axial inboard upper sprocket  21  through the chain  18 , shaft  25  and chain  17 . Guide plates  28 ,  29  engage rollers of the chain  17 ,  18  and constrain the respective stretches  31 ,  32  of the chains  17 ,  18  to generally vertical, straight lines. The guide plates  28  for the down stretch  31  of the chains  17 ,  18  is slightly out of plumb to provide adequate clearance for the motion of carriers  36  pivotally fixed to the chains  17 ,  18 . 
     The carriers  36  are shallow pan-like structures that, for example, can have a V-shaped cross-section. The carriers or buckets  36  are shorter than the spacing between the chains  17 ,  18  so that, as will be understood, the carriers can swing between the chains. At each end, a carrier  36  is pivotally connected to a chain through a rigid bracket  37  of T-shaped profile. The bracket  37  is pivotally fixed to a pin of a chain  17 ,  18  at  38 . A distal part of the bracket  37  is straddled by a pair of rollers  39 . As discussed below, the rollers  39  serve like cam followers to maintain a desired orientation of the carriers  36 . In the various illustrated views, the sprockets  21 ,  22  turn clockwise; the carriers  36  on the downward chain stretch  31  are concave upward and the carriers on the upward stretch  32  hang downwardly. 
       FIGS. 3A-3F  illustrate a transition of a carrier  36  from a hang-down position to a concave upward position, hereafter sometimes called a carrying position. A preliminary scan of these views illustrate that a carrier  36  pivots from the hang-down position through a space between the chains  17 ,  18 . These kinematics are produced by a cam  40  ( FIG. 4 ) fixed on the drive shaft  23  and driving a lever  41  through a cam follower  42 . The lever  41  oscillates a shaft  43  parallel to the sprocket drive shaft  23 . The shaft  43 , in turn, pivotally rocks or oscillates a pair of channels  44 , one adjacent each of the chains  17 ,  18 . The interior of the channels  44  is sized to receive a roller  39  associated with a carrier  36 . As noted, the brackets  37  provide a pivot connection  38  between a carrier  36  and a chain  17 ,  18 . 
     As a carrier  36  rises on the left chain stretch  32 , it is led by its associated rollers  39  ( FIG. 3A ). A roller bears against a vertical track plate  46  ( FIG. 4 ) until it is received in an associated channel  44 . The pitch diameter of the upper sprockets  21  is equal to the spacing of the carrier pivots  38 . The cam  40  is configured and timed to swing the channels  44  into the paths of the rollers  39  as the rollers approach the top of the plate  46 . As the sprockets  21  continue to rotate, the cam  40  causes the channels  44  to slow the rise of the rollers  39  relative to the chains  17 ,  18  thereby pivoting a carrier toward its carrying position ( FIGS. 3B-3D ). 
     As the pivot center  38  on a chain  17 ,  18  starts to descend ( FIG. 3E ), the channels  44 , still being located by the cam  40 , orient the carrier  36  to the carrying position. The distal end of the channels  44  align with generally vertical tracks  48  so that as the carrier  36  descends on the chain stretch  31 , the rollers  39  ride on the tracks  48 . The roller tracks  48  and chain tracks or guide plates  29  are parallel so that the concave up carrying orientation of a carrier  36  is maintained through the descent of the carrier until the rollers  39  run off the bottoms of the tracks  48  and the carrier is thereby released to pivot downwardly to a workpiece releasing position. 
     The sprocket drive shaft  23  and, therefore, the conveyor  16 , is preferably operated by a servomotor (schematically illustrated at  51  in  FIG. 4 ) synchronized with the speed and timing of the forming machine  10 . 
     The motor  51  rotates the shaft  23  so that a carrier  36  is located directly under the transfer fingers  12  when the transfer fingers are opened. A part or workpiece held by the transfer fingers  12  drops a relatively short distance, for example, in comparison to the depth of the adjacent frame sidewall which is a measure of the distance a part would otherwise be required to fall for removal from the machine. The kinematics of the carrier  36  adjacent the upper sprockets  21  do not require the carrier to rise above the plane of the workstations  11  when it transitions between a workpiece discharging orientation to the carrying orientation. At the bottom of the tracks, the rollers  39  and, therefore, the carrier  36  are released so that the carrier can swing to its downward hanging position and softly deposit a workpiece  52  on a chute  53  ( FIG. 1 ) or other delivery mechanism. 
     It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.