Abstract:
A high production multiple station endforming machine mounts a plurality of work stations upon an indexable rotary head whereby rotation of the head permits the work stations to be indexed between loading, operational and unloading positions. The workpieces are locked in jaw members operated by an over-center linkage wherein the position of the linkage is controlled by expansible chamber motors.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to multiple station endforming machines wherein work stations are indexed about an axis of rotation during operational cycles. 
     2. Description of the Related Art 
     Endforming machines are used to axially upset elongated workpieces, usually tubes, to form the end of a tube or produce an annular enlargement or diametric reduction, and may also do rolling, assembly and other secondary operations. The endforming tool engages the end of the workpiece while the workpiece is firmly held against axial displacement. Engagement of the tool with the workpiece causes the workpiece material to deform, and the workpiece holder may include configurations to receive and shape the deformed metal during displacement of the workpiece metal by the tool. 
     Conventional endforming machines consist of a single work station wherein the work station includes a work holder, usually in the form of jaws, for firmly gripping and positioning the workpiece prior to workpiece deformation. After the workpiece has been firmly clamped, the endforming tool is moved into engagement with the workpiece to deform the workpiece as desired. The workpiece is then removed from the work holder. Such single work station machines, while adequately shaping the workpiece by the endforming operation, are relatively low production in that each work station must be singly loaded and unloaded, and with the plurality of machine cycling, only a single part has been shaped. 
     Further, if secondary operations must occur on the workpiece, it must be reclamped for each operation which reduces the workpiece diameter and hardens and stresses the workpiece. 
     Previous attempts to increase the production of endforming machines have not been satisfactory for a number of reasons, and until the advent of the instant invention, high production endforming apparatus has not been available. 
     OBJECTS OF THE INVENTION 
     It is an object of the invention to provide an endforming machine having a high production capacity wherein the machine includes a plurality of work stations. 
     A further object of the invention is to provide a high production endform machine having a plurality of work stations indexing about an axis wherein various operations may be performed upon the workpiece at selected work stations and a finished workpiece is produced at each indexing. 
     Yet another object of the invention is to provide a multiple station endforming machine of rugged construction which is relatively economical to manufacture and wherein the workpieces may be effectively gripped and held by a linkage system, and the linkage system is operated by expansible chamber motors. 
     An additional object of the invention is to provide a multiple station endforming machine having a plurality of work stations indexing about an axis, and wherein tooling to perform secondary operations such as assembly procedures, rolling, threading or the like may be produced on the workpiece without reclamping thereof, and wherein it is possible to perform a number of workpiece operations prior to the workpiece being released from the endform machine. 
     SUMMARY OF THE INVENTION 
     The multiple station end forming machine in accord with the invention is mounted on a frame which supports a rotatable spindle. A circular head is mounted upon one end of the spindle consisting of a pair of spaced parallel plates, and a plurality of work stations are defined on the head between the head plates. In the disclosed embodiment, eight work stations are disclosed. 
     Each of the work stations includes a workpiece holder defined by a fixed jaw and a movable jaw. The workpiece holders&#39; jaws together define a cavity complemental in configuration and size to the workpiece whereby when the jaws are closed, a workpiece is firmly gripped by the holder. 
     In the disclosed embodiment, one of the jaws is pivotably mounted upon the head, while the other jaw is fixed to the head. An over-center linkage operates each pivoted jaw wherein movement of the linkage to its over-center position closes the jaws of a work station to firmly lock the jaws in the closed position for gripping the workpiece. Upon the over-center linkage being shifted to a less-than-center position, the movable jaw is pivoted to an open condition releasing the workpiece. 
     The spindle head, and spindle, is rotatably indexed about the axis of the spindle, and such indexing is produced by an indexing motor. The endforming tool, or tools, mounted upon the frame which align with the workpiece during indexing may be operated by an expansible chamber motor. 
     While the over-center linkages operating the work station jaws are mounted upon the head and indexed therewith, actuating members mounted upon the frame selectively operate the over-center linkage to open or close the work station jaws. In this manner, the workpieces are gripped, or released, as desired at the appropriate position during the indexing of the head. 
     The frame includes a mounting sleeve having a plurality of flat mounting surfaces whereby tooling may be affixed thereto for producing the various operations at each indexed position of the head. For instance, in the disclosed embodiment wherein eight work stations are shown, the sleeve will have eight mounting surfaces for tooling. 
     Each indexing of the head will produce a completed workpiece upon which all of the desired operations have occurred. The average cycle time of the endform machine will be six seconds between indexes, and in the disclosed embodiment of the invention, six machining operations, in addition to loading and unloading operations, can be produced during each indexing of the head. 
     An endforming machine in accord with the invention may be made substantially fully automatic. By the use of known timing and cycling air or pressurized oil circuits, the operation of the endforming machine can be automated, and the high production rate achieved by a multiple station endforming machine in accord with the invention lowers the cost of forming parts by endforming. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The aforementioned objects and advantages of the invention will be appreciated from the following description and accompanying drawings wherein: 
     FIG. 1 is a front elevational view of a multiple station endforming machine utilizing the inventive concepts, 
     FIG. 2 is an elevational sectional view taken through the machine spindle and head taken along Section  2 — 2  of FIG. 6, only one work station being shown for purpose of illustration, 
     FIG. 3 is an elevational enlarged partial view of a work station illustrating the work holder jaws being maintained in the closed position by the over-center linkage, 
     FIG. 4 is a view similar to FIG. 3, illustrating the relationship of the components when the linkage is in the open position, 
     FIG. 5 is a detail view of the linkage operating mechanism illustrating the alignment of the linkage release actuator with the linkage release actuator lever, 
     FIG. 6 is an elevational view taken along Section  6 — 6  of FIG. 2, and 
     FIG. 7 is a detail elevational view of the clamp release expansible chamber motor. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIG. 1, it will be appreciated that a multiple station endforming machine in accord with the invention includes a frame generally indicated at  10  consisting of cross members  12  and columns  14  welded together to define a box-like structure which includes a front support plate  16 , FIG. 2, and a rear support plate  18 . 
     A tubular spindle  20  is rotatably mounted upon the support plates  16  and  18  by front bearings  22  and rear bearings  24 . A bull gear  26  is bolted to the end of the spindle  20  having teeth  27 , while the front end of the spindle extending through the bearings  22  includes a generally circular head  28  defined by an outer plate  30  and an inwardly axially spaced inner plate  32 . 
     The spindle  20  and head  28  are rotatably indexed by an hydraulic rotary indexing motor  34  having a gear  35  meshing with bull gear teeth  27 . operation of hydraulic motor  34  is by a conventional indexing motor control circuit, not shown. 
     A plurality of work stations  38  are defined upon the head  28  usually evenly spaced about the circumference of the head  28 , and in the disclosed embodiment, FIG. 1, eight work stations  38  are defined. Each work station includes an opening  40  defined in the outer plate  30 , and as will be later appreciated, the work stations  38  are formed by workpiece holding means which include a pair of jaws. 
     The workpiece holder at the work stations  38  includes a fixed jaw  42 , FIGS. 3 and 4, located between the plates  30  and  32 . Also, the work holder includes a pivoted jaw  44  located within the plates  30  and  32  pivotably mounted upon the pivot pin  46 . The jaw  42  includes an insert and recess  48 , while the pivoted jaw  44  includes the insert and recess  50 . When the jaws  42  and  44  are pivoted to the closed position shown in FIG. 3, the recesses of the inserts  48  and  50  align to define a circular opening for receiving a workpiece, not shown, therein, FIG.  3 . 
     Opening and closing of the pivoted jaw  44  is produced by an over-center linkage generally indicated at  52 . The linkage  52  includes a link  54  pivoted at  56  to the jaw  44  and also includes a pivot  58  pivotably connected to link  60  which is pivoted to the anchor  64  at  62 . A small link  66  is pivotably connected to the links  54  and  60  by pivot  58 , and the link  66  includes the pivot  68  connected to the axially displaceable rod  70 . 
     The rod  70  is guided for generally radial movement relative to the spindle axis upon a guide  72  mounted upon the head  28 , and the rod  70 , at its outer end, includes a pad  74  for engagement with an expansible chamber piston extension, as later described. A rod  76  aligns with the rod  70 , FIGS. 3 and 4, and the rod  76  includes a sleeve  78  upon which a nut  80  is threaded. The rod  76  and sleeve  78  is axially slidable within the guide  82  mounted between plates  30  and  32 , and rack teeth  84  are defined along a portion of the sleeve  78 . A tooth gear  86  is rotatably mounted upon the guide  82  and is rotated by the lever  88 , FIG. 5, whose end is in alignment with an actuating expansible chamber motor as later described. 
     The workpiece endforming tool  90 , FIG. 2, is mounted upon a tool stem  92  guided in bearing block  93  and the stem is an extension of the piston  94  of the expansible chamber motor  96 . The tool  90  will align with a workpiece held within the jaws  42  and  44  when a work station  38  is indexed and held in its operative position. In this manner, movement of the piston  94  to the left, FIG. 2, causes the tool  90  to enter the end of a workpiece, not shown, axially displacing the workpiece material to form the desired configuration on the tubular workpiece, or its end, in a typical endforming operation. The block  93  and motor  96  are mounted on the frame tool drum or sleeve as later described. 
     Shifting of the linkage  52  to the closed position shown in FIG. 3 is accomplished by an extension  98  of the expansible chamber piston  100  of the expansible chamber motor  102  mounted on bracket  103  bolted to the tool drum, FIG.  2 . The extension  98 , upon movement of the piston  100  radially inwardly, will engage the pad  74  of rod  70  and move the linkage  52  to the over-center relationship shown in FIG. 3, which closes the pivoted jaw  44  relative to the fixed jaw  42  permitting the workpiece to be tightly gripped within the recesses  48  and  50 . 
     When it is desired to open or unlock the linkage  52  to pivot the jaw  44  to the open position shown in FIG. 4, the piston extension  104 , FIG. 2, is moved to the left, FIG. 2, by the piston  106  of the expansible chamber motor  108  mounted on the frame rear support  18 , FIG.  7 . Movement of the extension  104  to the left, FIG. 2, causes the end of the extension  104  to engage the gear lever  88  rotating the gear  86  which axially translates the sleeve  78  and moves the rod  76  radially outwardly with respect to the spindle axis. Such movement of the rod  76  outwardly, through the pivot pin  68  and linkage  66 , causes the links  54  and  60  to collapse as shown in FIG. 4 breaking the “over-center” relationship of these links and pivoting the jaw  44  to the open position shown in FIG.  4 . 
     To insure that the head  28  will be firmly locked against rotation while the workpiece is being worked upon when held within the jaws  42  and  44 , an expansible chamber motor  110  includes a piston extension  111  which moves the guided detent  112  into a hole  115  defined in the head inner plate  32 . The detent  112  is closely received within the bushed holes  115  to prevent rotation of the head  28  while work is occurring at the work stations  38 . 
     An octagonal tool drum or sleeve  116  is mounted upon the frame  10  between the front support  16  and rear support  18  as will be appreciated from FIG.  2 . The octagonal configuration of the tool drum  116  is best appreciated from FIG. 6 wherein it will be appreciated that the tool sleeve is formed by a plurality of plates  118 . The tool sleeve  116  is of an octagonal configuration because, in the disclosed embodiment, eight work stations  38  are disclosed. If an end forming machine in accord with the invention is provided with six work stations, the tool sleeve will be of a hexagonal configuration, the number of plates  118  conforming to the number of work stations. Because the tool sleeve  116  is mounted upon the frame front and rear supports, the tool sleeve is stationary and the head  28  will index relative to the drum sleeve. 
     The purpose of the tool sleeve or drum  116  is for the purpose of mounting tools and machine operating components thereon. In this respect, the outer surfaces  120  of the plates  118  are axially notched at  122  in order to receive the keys of tools mounted on the plates  118 , and holes  124  may be threaded to receive bolts used to mount tools upon the plates. As shown in FIG. 6, tools  126 , such as shown in dotted lines, may represent assembly tooling, rolling or threading tools, or the like. In this manner, the workpiece will be presented in alignment with appropriate tooling mounted upon the tool drum  116  as the head mounted workpiece is indexed for alignment with tools mounted upon the tool drum. 
     The tool drum also supports the endforming tool bearing block  93 , and the expansible chamber motor  96  and the bracket  103  is also bolted to the tool drum. 
     From the above description, it will be appreciated that as the head  28  is indexed about the axis of the spindle  20 , the work stations will be sequentially in alignment with the endforming tool  90 , and with any tooling mounted upon the tool drum  116 . As the endforming machine disclosed will permit a number of sequential operations to be formed on the endformed part prior to the workpiece being unclamped, each indexing of the head  28  will permit a finished workpiece to be released from its associated work station  38 , resulting in a high production rate. 
     One of the advantages of an endforming machine in accord with the inventive concepts is that it is only necessary to grip the workpiece once even though a plurality of diverse operations may be imposed upon the workpiece. In known endforming machines, it is necessary to release the workpiece after the endforming operation and re-grip the workpiece during each sequential secondary operation. With the invention, the workpiece only need be gripped or clamped once, and the secondary operations after endforming are completed before the workpiece is released from the machine. As sequential clamping and unclamping of tubular workpieces causes the workpieces to be slightly compressed, causing work hardening and stress of the workpiece, significant quality control advantages are achieved by the machine of the invention. 
     It is appreciated that various modifications to the inventive concepts may be apparent to those skilled in the art without departing from the spirit and scope of the invention.