Abstract:
This invention relates to an improvement in an automatic apparatus and method for coupling a workpiece to a specified position along a continuous length of ribbon and then cutting a length of ribbon therefrom to a predetermined length, which improvement provides for grasping the cut length of ribbon and welding the ends together. A pair of clamping jaws grasps a piece of ribbon at a predetermined position just prior to cutting the ribbon from a continuous length of ribbon, then turns the ribbon to align the end over a sonic welding anvil, and welding the ends of the ribbon together and discharging the ribbon from the apparatus.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention is an improvement over our prior U.S. Pat. No. 4,017,955, dated Apr. 19, 1977, for an Apparatus For Attaching a Workpiece to A Continuous Length of Line, and reference may be had thereto for a better understanding of the present invention. 
     In this prior patent, an apparatus is provided for coupling a workpiece to a specified position along a continuous length of material, and then cutting the length of material therefrom to a predetermined length. The present improvement provides for an apparatus and method for grasping the cut length of material prior to the final cutting of the material then cutting the material and positioning the ends of the cut material in an ultrasonic welder, heat sealer, or similar joining apparatus, to fuse or coalesce the ends together with a predetermined overlap and then discharging the ribbon with connected ends and workpiece attached from the apparatus. Thus, an automatic apparatus attaches a workpiece and cuts the ribbon from a continuous length to a predetermined length and then the ends of the ribbon are joined to form an endless loop which is used as an operative element in a bomb fuze. 
     II. Description of the Prior Art 
     Heretofore it has been customary to couple a line or ribbon through a workpiece threading the ribbon through multiple sequential apertures located in the workpiece. It was then necessary to move the workpiece along the ribbon to the required position, and to tension the ribbon over the workpiece prior to cutting the ribbon to the predetermined length. Due to the complexity of the threading operation, it was often necessary to accomplish the entire procedure by hand labor, an operation which was both expensive and slow. In the alternative, complex threading machines were required to thread an end of the ribbon through the appropriate aperture in the workpiece. These threading machines were not only slow, but were also subject to breakdown when the subject threading element missed the aperture and was impaled upon the workpiece. Furthermore, even after the ribbon was threaded through the aperture in the workpiece, it was necessary to pull the ribbons through the workpiece with great accuracy so that the workpiece would be located at a specified position along the predetermined length of ribbon. 
     In response to these problems, an apparatus was developed utilizing an arcuate-shaped workpiece having special one-way apertures located adjacent each end thereof. One-way apertures were specially designed to receive a folded section of the ribbon when tension was placed upon the ribbon. It was folded to thereby retain the ribbon within the one-way aperture in the workpiece. By stuffing the folded ribbon through the one-way aperture, the necessity to pull the ribbon through the workpiece or to move the workpiece to the specific location along the ribbon was eliminated. This locating procedure is easily accomplished by prearranging the specificed position of the ribbon adjacent to the one end apertures of the workpiece prior to the folding and stuffing process as taught in prior U.S. Pat. No. 4,017,955, dated Apr. 19, 1977. The ribbon having a workpiece attached at a predetermined position and cut to a predetermined length was then discharged into a receptacle where an operator fused the ends of the ribbon together in an ultrasonic welder. The present improvement to the prior apparatus and method provides for an apparatus for grasping the cut length of ribbon prior to the final cutting to a predetermined length then cutting the continuous length of ribbon to its predetermined length, then twisting the cut length of ribbon to place the ends on the anvil of an ultrasonic welder, fusing the ends together with a predetermined overlap to form an endless loop of predetermined length with a workpiece positioned at a predetermined position on the loop, and then discharging the ribbon for a later connection to a bomb fuze apparatus. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a method and apparatus for grasping a cut length of ribbon and positioning the ends thereof in an ultrasonic welder with a predetermined overlap of the ends and connecting the ends to form an endless loop which apparatus and method forms a part of an apparatus and method for coupling a workpiece to a specified position along a continuous length of ribbon and then cutting a length of ribbon therefrom to a predetermined length. The improvement has two pair of clamping jaws for clamping the length of ribbon prior to the cutting to a predetermined length from a continuous length of ribbon, then cutting the predetermined length of ribbon from the continuous length thereof, then positioning the ends of the ribbon onto an anvil of an ultrasonic welder with a predetermined overlap of the ends of the ribbon and fusing the ends together to form an endless loop and finally, discharging the endless loop of ribbon having a workpiece attached thereto from the apparatus. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Other objects, features, and advantages of the present invention will be apparent from the written description and the drawings in which: 
     FIG. 1 is a frontal perspective view of an apparatus in accordance with the present invention; 
     FIG. 2 is a diagrammatic view of the cycles for the major components of the system; 
     FIG. 3 is a perspective view of portions cut away in a starting position; 
     FIG. 4 is a perspective view in accordance with FIG. 2, with the apparatus in a clamping position; 
     FIG. 5 is a perspective view of the clamping jaws positioning the ends of the ribbon on the anvil of the ultrasonic welder; and 
     FIG. 6 is a perspective view of a portion of the apparatus during the fusing of the ends of the ribbon together. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An apparatus in accordance with the present invention is illustrated in the drawing, which is substantially the same as the invention of U.S. Pat. No. 4,017,955, except for the improvements in the handling of the cut ribbon. 
     A frame 10 is illustrated in FIGS. 1 and 3, having a continuous nylon ribbon 11 being fed to the machine from one end and having a vibratory plate 12 mounted onto a frame portion 13 having a workpiece feed longitudinal guide member 14 thereon for feeding workpieces 15 to a mechanism for attaching the workpieces to the ribbon 11 which included a first stuffing cylinder 15 and a second stuffing cylinder 16, each for stuffing the ribbon into a portion of each workpiece 19. The ribbon is initially pulled to the next position by a pair of advance jaws 17 operated by advancing jaws cylinder 18 having an upper jaw 20 and a lower jaw 21 for moving forward to engage the ribbon adjacent the hot wire cutter 22, mounted to the cutter means 23. The cutter means on a predetermined timing stroke moves to cut the ribbon 11 with the hot wire cutter 22, and then moves out of the way, so that the advance jaws 17 can move forward and engage the ribbon and pull it through for the next position under the hot wire cutter 22. Simultaneously, it pulls the ribbon behind the hot wire cutter for positioning the ribbon for the next workpiece to be attached at a predetermined position. The present apparatus has a central control box 24 to centrally control the operation of the apparatus for incorporating the different switches and timing cam. 
     A vibratory feed bowl 25 has been added, which through vibrations, feeds the workpieces 15 in an upright position onto the workpiece feed guide member 14. The vibratory bowl feed 25 is a conventional feed used in a variety of industries. The advance jaws 17 advance and engage the ribbon 11 adjacent the hot wire cutter 22 and the return pulling the ribbon with it at which time the ribbon is grasped by the clamping jaws 26 and held taunt between the advance jaws 17 and the clamping jaws 26. Clamping jaws 26 are actuated by a cylinder 27 and then the ribbon 11 is cut by the hot wire cutter 22. The vibratory workpiece feed 14 feeds workpieces 19 to a support with the stuffing members 15 and 16 stuffing the ribbon into each side thereof at a predetermined position between the clamping jaws 26 and a pair of clamping jaws not illustrated. In the prior patent, once the hot wire cutter 22 cuts the ribbon 11 at the predetermined position, the jaws 17 release the ribbon and it is dropped on a guide into a receptacle. 
     In the present improvements, a pair of clamping jaws 30 and 31 are positioned at appropriate locations for grasping the ribbon 11 at that location between the jaws 17 and the hot wire cutter 22. Once the ribbon is clasped by the jaws 30 and 31, it is released by the advance jaws 17 and cut by the hot wire cutter 22, whereupon the jaws 30 and 31 are pulled back and rotated to position the ribbon as illustrated in FIG. 4 with the end of the cut ribbon overlapping on an anvil 32 of an ultrasonic welder 33. The ultrasonic welder thereupon has a welding post 34 which comes down upon the anvil and ends 35 and 36 of the ribbon 11 to fuse the ends together. A heat sealer or staking mechanism could alternatively be employed for connecting the ends of the ribbon. Once the jaws 30 and 31 are released, the ribbon is formed into an endless loop of a predetermined size having a workpiece 15 attached at a predetermined position and is dropped through an opening 37 in a base frame support 38. The workpiece 15 and ribbon are turned in the proper direction during the looping of the ribbon by a looping guide member 40 having a spring portion 49. The guide 40 is attached to the frame 10 in a position to engage the workpiece 15 attached to the ribbon 11 to twist the workpiece and the ribbon in a looping direction as the jaws 30 and 31 are rotated. 
     Jaw 30 is operated by an air line 41 while jaws 31 are operated by air line 42 which actuates small air actuators when air pressure is applied thereto. Hydraulic or electronic actuators also could be employed. The jaws 30 are mounted to a rotary base 43 while the jaws 31 are mounted to a rotary base 44, which are mounted to rotate on a solid lubricant disc 45 placed under each rotary base 43 and 44. The jaws are rotated by a rotary or mechanical air actuator which is activated for base 43 by a pair of air lines 46 and for base 44 by a pair of air lines 47. In addition, the rotary actuators 48 for jaws 30 and base 43 and for jaws 31 and jaw support 44 are mounted to a frame portion 51 and 52 respectively. The frame portion 51 is supported by a pair of sliding shafts 53 sliding in bushings in frame portion 54 and is driven by an air cylinder 55 also attached to the frame portion 54 with a driving rod attached to the frame 51. Frame portion 52 is supported by a pair of sliding shafts 56 and is driven by a rod 57 of a pneumatic cylinder 58 attached to the frame 54. Sliding shaft 56 slides in bushings mounted in the frame 54 in the same manner as the rods 53. The jaws 30 and 31, base members 43 and 44 are mounted through slots 60 and 61 in the base frame portion 38 with rotating shafts 62 and 63 protruding through spacers 64 for engaging the rotating members 43 and 44 for rotation upon actuation of the actuators 48 and 50. 
     In operation, the clamping jaws 30 and 31 are in the position as illustrated in FIG. 3, are rotated by actuating the rotary actuators 48 and 50 to face the ribbon 11 in its position as shown in FIGS. 1, 3, and 4. Then jaws 30 and 31 are then slid forward on the support shafts 53 and 56 by the pneumatic cylinders 55 and 58 with jaws 30 and 31 being in their normal open position, until the jaws extend over and under the ribbon 11 as illustrated in FIG. 4. The clamping jaws 30 and 31 are then actuated by the application of air pressure to the air lines 41 and 42 to close the jaws 30 and 31 to clamp the jaws upon the ribbon 11 at predetermined positions as determined by the positioning of the slots 60 and 61 support shafts 53 and 56 and the frame 54. Once the jaws 30 and 31 are clamped, the ribbon is cut with a hot wire cutter 22 or hot knife and the advance jaws 17 release the ribbon which is then supported by the clamping jaws 30 and 31. Clamping jaws 30 and 31 are then rotated with the jaws 30 rotating in a clockwise direction and the jaws 31 in a counter-clockwise direction towards each other thereby looping a portion of the ribbon 11 between the jaws 30 and 31. The ribbon is flipped down by the guide member 40 engaging the workpiece 10 at a downward angle to flip the ribbon in the proper direction as illustrated in FIG. 5 in which the ends 35 and 36 of the ribbon 11 has been placed on the anvil 32 of the ultrasonic welder 33. Jaws 33 and 34 are rotated by the rotating actuators 48 and 50 and simultaneously are retracted by the cylinders 55 and 58 to slide the jaws in the slots 60 and 61. Once the ribbon ends 35 and 36 are properly positioned and ultrasonic welder 33 is actuated to lower the ultrasonic welding post 34 into the ribbon ends as shown in FIG. 6, to sonically weld or fuze the ends together to form an endless loop of ribbon of a predetermined length having a workpiece 15 positioned at a predetermined position. When the welding is completed the clamping jaws 30 and 31 are released and the ribbon drops into a chute through the opening 37 where it can be delivered to a receptacle for attachment to a bomb fuze in a separate operation. 
     It should be clear that the operation of the machinery has been described in terms of the use of air cylinders and air actuators, but that hydraulic as well as electrical solenoids and cylinders can be used without departing from the spirit and scope of the invention. In addition, a pair of air lines 46 and 47 drive the rotary actuators 48 and 50 which allows the actuators to be driven in a clockwise and counter-clockwise in one rotation and to be driven in a reverse direction simultaneously for placing the jaws in a different position. Thus, the jaws are rotated and advanced to engage the ribbon and rotated in the opposite direction and retracted to position the ribbon, then released to discharge the endless looped ribbon portion. 
     Timing is accomplished through a cam switch timer actuating time switches to operate valves for the air cylinders and might follow a 360° sequence in the present improvements of having the advance jaws 17 advanced and closed upon the ribbon 11 at 190° then have the main clamp 26 open at 210° followed by the advanced cylinder retracting pulling the tape to a new cut off position beginning at 230°. At 290° the main clamp can close again while the air signal off the main clamp 26 actuator 27 can shift the control valve to actuate the rotary actuators 48 and 50 to rotate the jaws 30 and 31 to the full pick-up position, and to simultaneously actuate the cylinder 55 and 58 to extend the jaws 30 and 31 forward to pick-up position. When the cylinders 55 and 58 are fully extended the air signal off the cylinder may shift a control valve which closes the jaws 30 and 31. The hot wire cutter 22 is actuated at 340° to the cutting positions, thus cutting the ribbon 11. At 0° the advance jaws 17 are opened and an air signal off the advance jaws actuator is actuated by the advance cylinder being fully retracted actuates the rotary actuators 48 and 50 to reverse the rotation of the jaws 30 and 31 to the weld position and to retract the cylinders 55 and 58 back to the welding position. The traveling of the air cylinder backwards trips an electrical switch which starts the weld cycle to lower the ultrasonic horn 34 into the anvil 32, and the power supply to actuate the ultrasonic welding horn automatically, and to open the clamping jaws 30 and 31. After the welding is complete, the ultrasonic horn raises to release the completed tape assembly. At 20° the hot wire cutter 22 retracts to its normal position and at 60° the advance cylinder extends the advance jaws to the end of the tape. FIG. 2 illustrates the cycles for components as follows: 
     A--Advance Jaws 
     B--Main clamp 
     C--Rotary Actuators 48 &amp; 50 
     D--Hot Wire Cutter 
     E--Jaws 30 &amp; 31 
     F--Lower Welder Horn 
     G--Weld Cycle 
     H--Advance Jaws Cylinder 
     I--Stuffer 15 
     J--Stuffer 16 
     It should be clear that the sequence for the improvements, of course, can be varied as desired without departing from the spirit and scope of the invention and that this sequence follows the timing sequence for the rest of the apparatus. 
     It should also be clear that the valves can be turned on not only by cam timing, but by the movement of different components actuating different switches both pneumatic or electrically without departing from the spirit and scope of the invention. The ultrasonic welder 33 is a conventional commercial ultrasonic welder complete with controls for actuating the lowering of the horn onto the anvil, welding and retracting of the horn. A method and apparatus has been provided for grabbing a tape in the proper sequence at the proper position from an apparatus which has attached a workpiece to the tape and cut the tape to a predetermined length, and to rotate one grabbed tape while simultaneously moving it to position the ends of the tape in an overlapping position onto an anvil of an ultrasonic welder and ultrasonically welding the ends and discharging the tape thereby producing an endless loop tape of predetermined size having a workpiece attached at a predetermined position in a predetermined manner. It should, however, be clear that the present invention is not to be construed as limited to the particular forms as disclosed herein which are to be considered illustrative rather than restrictive.