Abstract:
The present invention comprises a method and an apparatus for rapidly orienting and advancing buttons to be sewn. The invention employs a Programmable Logic Controller to control the steps of orientation and advancement and eliminates the need for time consuming set-up and adjustment of limit switches to control the movement of components within the button oriented and advancer. The use of a Controller to actuate the steps of orientation and advancement allows for the reduction of parts and consolidation of parts onto one plate that may be easily affixed to an industrial sewing head.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to machines for sewing buttons and specifically machines for the loading, advancing, aligning, sewing, and ejecting of buttons at a rapid pace. The prior art includes add-on units for use in combination with industrial sewing heads to accomplish these objects. These prior art devices have traditionally demanded multi-step, labor intensive installation including many adjustments to ensure proper placement of interrelated mechanical parts. Such prior art machines have used swing arms, rotary discs, or other elements to move buttons into position under a sewing needle and to subsequently displace the original button and advance a new button into position. U.S. Pat. Nos. 4,594,953, 4,884,517, and 5,062,373 all demonstrate prior art button loading or sewing devices. 
     The prior art also includes Mckee Button&#39;s own “Buttonmatic 1097” which employs a button feeding track to carry buttons from a vibrating dish type dispenser to a button chute located on a clamp assembly positioned generally below and behind the sewing needle. The clamp assembly of the 1097 receives buttons from the track into a button chute. A gear assembly with button hole pins aligns buttons within the chute to receive a needle and thread, and advances buttons to the sewing position. The 1097 also includes two side panel control plates mounted on the upper arm of the industrial sewing head. These side panel control plates use limit switches and precise adjustments to mechanically drive and control the various functions (rotate, advance, tilt, and return) that must be performed upon the button engaging portion of the 1097. 
     Air cylinders on the side panels drive extension rods that move hinged or sliding push rods to control the gear assembly that lies below on the clamp assembly. These air cylinders operate based upon the mechanical activation of limit switches that have been carefully arranged to contact moving parts, such as the push rods, in the desired sequence. This careful arrangement also determines the stroke length for the motion of parts and, as such, precise placement of limit switches is an important objective of set up and maintenance on the 1097. 
     SUMMARY OF THE INVENTION 
     The present invention is a simplified device for use with a sewing machine for the loading, aligning, and advancing of buttons. Control of a button orienting gear assembly is provided directly through a Programmable Logic Controller and electric air valves. The Controller coordinates the delivery of compressed air to various air cylinders. Each air cylinder, in turn, provides force to advance, tilt, or orient the gear assembly. A diagonal spring exerts a return force to bring the gear assembly back to a resting state after an advance and tilt step. By eliminating limit switch control as the primary means for gear assembly orientation, tilt, and advance, numerous parts are eliminated. The invention greatly reduces the time required to set-up an automatic button sewing attachment because it eliminates the need to carefully position a series of limit switches upon mounting plates with setting screws. In the prior art, these limit switches served to police the range of motion for mechanical push bars and to coordinate, in sequence, the steps to advance, tilt, and orient button engaging pins. Because the timed control of cylinder actuation through a Controller replaces the activation of air cylinders through mechanically activated limit switches, the precise adjustments of the prior art no longer need to be performed by the end user. In addition, the preferred embodiment of the present invention includes a compact arrangement of parts on a mounting surface, such as single clamp frame, rather than arrangement on a clamp frame and on separate side plates. This simplified design reduces installation steps, simplifies operation, and eliminates the movement of interrelated mechanical parts from the sides of the sewing heads (where they may more easily be damaged by contact from a user). The present invention may also be practiced with the use of motive means other than extension cylinders to drive the orient, advance and tilt steps. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the clamp assembly. 
     FIG. 2 is a detailed front elevation front view of the gear orienting assembly. 
     FIG. 3 is a perspective view of the underside of the clamp assembly. 
     FIG. 4 is a perspective view of the control box, vibrating unit, button track, and assemblies. 
     FIG. 5 is a top view of the clamp assembly. 
     FIG. 6 is a top view of the partially disassembled gear assembly. 
     FIG. 7 is a top view of the disassembled button chute. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention relates to a button sewing apparatus that includes a clamp assembly  2 , a chute assembly  4 , an orient gear assembly  6 , a Programmable Logic Controller  8 , a vibrator  10 , and a button dish  12 . Industrial sewing heads  14  that are well known in the art typically comprise a base  16 , a rear post  18 , and an upper arm  20 . The upper arm  20  includes the housing for a sewing needle  22  that is positioned on the upper arm  20  front end, away from the rear post  18 . The presently preferred embodiment of the invention is an accessory that may be added to an industrial sewing head. However, the present invention may also be an integral component of a sewing machine rather than a separately manufactured accessory. In the preferred embodiment, the clamp assembly  2  is mounted on the sewing head base  16  under the upper arm  20 . The chute assembly  4  and orient gear assembly  6  are mounted on the clamp assembly  2 . 
     The clamp assembly  2  includes a clamp frame  24  that serves as the superstructure on which the other assemblies  4 ,  6  and the other components of the clamp assembly may be mounted. The clamp frame  24  has a rear end and a front end, and the clamp frame  24  is attached to the sewing head  14  by a clamp pivot  26  located on the clamp frame  24  rear end. The clamp frame  24  front end includes a sloped chute assembly mounting face  28  and a drive shaft tunnel  30 . Air cylinders,  32 - 34 , mounted on the clamp frame  24 , include air cylinder housings and longitudinally extendable rods. The air cylinders include an advance air cylinder  32  mounted generally above and parallel with the drive shaft tunnel  30  a tilt air cylinder  34  mounted generally behind the sloped chute assembly mounting face  28  and in a generally perpendicular arrangement with the drive shaft tunnel  30 , and an orient air cylinder  36  mounted generally beside and parallel with the drive shaft tunnel  30 . Although the scope of the present invention is not limited to the presently described arrangement of cylinders, this arrangement is preferred due to the reduction in parts that may be achieved and the compact design. Cylinder arrangement on the clamp assembly  2  is made possible by the elimination of limit switches which occupied space and necessitated side plate controls in the prior art. 
     The chute assembly includes a chute  38  mounted on the clamp frame&#39;s sloped chute assembly mounting face  28 . The chute  38  includes first and second chute side walls  40 ,  42  that form a button path  44  therebetween. The upper, rear portion of the button path  44  defines a point of entry for buttons fed into the chute  38  from a flexible track  60 . Lower on the sloped button path is a button sewing position. At the button sewing position, the first chute side wall  40  includes a button sewing depression  46 . Attached to the second button chute side wall generally across the button path  44  from the sewing depression  46  is a chute spring  48  that includes a chute spring anchor  50  and a chute spring wire  52 . The chute spring anchor  50  is mounted on the second chute sidewall  42  and the chute spring wire  52  is attached to a spring plunger  54  located in a spring plunger recess  56  in the second chute side wall. The chute spring wire  52  is flexed or bowed to present a spring force directed across the button path and towards the sewing position depression  46 . This spring force, asserted against a button in the sewing position, aids to secure the button so that the button may be sewn. The chute cover  58  covers the button path  44 . A flexible button track  60  extends from the rear of the chute  38  and button path  44  to a button source. 
     The front portion of the orient gear assembly  6  is positioned over the chute assembly  4 . The orient gear assembly  6  includes a gear housing  62  that contains an orienting gear  64  with downwardly extending pins  66 , a pinion gear  68 , and a gear actuator  70 . The gear housing  62  is attached to the front end of a drive shaft housing  72  that extends rearwardly therefrom and through the drive shaft tunnel  30  of the clamp assembly  2 . A generally cylindrical drive shaft  74  is located within the drive shaft housing  72  and extends into the gear housing  62 . The drive shaft  74  is sliceable within the drive shaft housing  72 , and the drive shaft housing  72  is rotatable about its longitudinal axis. The gear actuator  70  is mounted on the drive shaft  74  and may engage the pinion gear  68  to rotate the pinion gear  68  which, in turn, rotates the orient gear  64 . 
     The drive shaft  74  and drive shaft housing  72  extend rearwardly from the gear housing  62  through the drive shaft tunnel  30 . The drive shaft  74  extends outwardly from a rear exit of the drive shaft tunnel  30  and through a first opening  78  in the orient cylinder mount  76  and a first opening  80  in an orient arm  82 . A tilt arm  84  is attached to the top of the orient cylinder mount  76 . A housing return spring  86  extends from the tilt arm  84  to a location on the top of the clamp frame  24  behind the tilt arm  84 . 
     An advance air cylinder  32  is mounted on the clamp frame  24  by an advance mount  88 . Preferably, the advance air cylinder  32  is mounted generally parallel with the drive shaft  74  and drive shaft housing  72 . An advance extension rod  90  that is longitudinally extendable from the forward end of the advance air cylinder  32  is attached to a size plate  92  that extends downward from the advance extension rod  90  and engages the gear housing  62 . 
     A tilt air cylinder  34  is mounted on the clamp frame  24  preferably with the tilt air cylinder longitudinal axis located generally perpendicular to the drive shaft  74  and drive shaft housing  72 . The tilt extension rod  94  is longitudinally extendable from within the tilt air cylinder  34 . When extended, the tilt extension rod  94  communicates force to the tilt arm  84 . 
     An orient extension rod  96  extends longitudinally from the orient cylinder  36  positioned generally parallel with the drive shaft housing  72 . The orient extension rod  96  extends rearwardly through an orient mount  76  second opening  98  and an orient arm  82  second opening  100 . The orient extension rod  96  is secured to the rear side of the orient arm  82 . 
     In operation, the Controller  8  opens air valves to supply compressed air to the air cylinders in an appropriately timed order to effect the following sequence (from an assumed starting position wherein the orient pins  66  engage a properly aligned button that lies in the loading position in the button path  44  of the chute  38 ). When provided with a supply of compressed air, the advance air cylinder  32  forces the advance extension rod  90  forward, which causes the size plate  92 , and the rest of the gear housing  62 , to move forward along the drive shaft  74  and against the resistance of the housing return spring  86 . This advance step moves a button from the loading position in the button path  44  of the chute assembly  2  to the sewing position. 
     Next, the Controller  8  opens the appropriate valve to supply compressed air to the tilt air cylinder  34 . Actuation of the tilt air cylinder  34  causes the tilt extension rod  94  to extend and strike the tilt arm  84 . The application of force upon the tilt arm  84  by the tilt extension rod  94  causes the tilt arm  84 , orient cylinder mount  76 , orient arm  82 , orient cylinder  36 , and drive shaft housing  72  to rotate. This rotation of the drive shaft housing  36  forces the gear housing  62  to tilt away from the sewing position. This upward tilt disengages the orient pins  66  from the advanced button. 
     When the orient pins  66  are disengaged from the button, and the gear housing  62  is in a tilted position, and when the Controller  8  no longer supports the advancement of the advance air cylinder  32 , the diagonal spring  82  may draw the tilt arm  84 , orient cylinder mount  76 , and orient arm  82  back to their resting positions, and the gear housing  62  and drive shaft housing  72  to their rear positions. While the diagonal spring draws the drive shaft  74  rearward, the PLC Controller  8  supplies compressed air to the orient air cylinder  36 . This actuates the orient air cylinder  36  and causes the orient extension rod  96  to force the orient arm  82  and drive shaft  74  rearward. This rearward motion of the drive shaft draws the drive shaft  74  rearward within the drive shaft housing  72  and gear housing  62 . As a result, the gear actuator  70  is pulled against and rotates the pinion gear  68  which, in turn, rotates the orient gear  64 . The rotating pins  66  attached to the orienting gear  64  fall into the button waiting in the button loading position when the gear housing  62  and rotating orient pins  66  return from the tilted and advanced position. When the orient pins  66  engage the button, continued rotation causes the button to become properly oriented for receipt of a needle and thread. 
     Preferably arranged in a separate or stand-alone unit apart from the industrial sewing head is the Controller  8  and air valves. Using a convenient power source and working fluid, preferably a 115 volt electric source and compressed air at 45 PSI, the controller  8  opens and closes the above referenced air valves to communicate compressed air through conduits, such as hoses, to the cylinders  32 ,  34 ,  36 . As previously described, the air cylinders in turn control the advance, tilt, orient, and return of the orient gear assembly  6 . The Controller  8  also controls power to a start unit that is affixed to the sewing head and which allows a user to start the sewing machine, and the button sewing sequence, with a foot pedal. Finally, a vibrating unit  10  and button dish  12 , may be used in combination with the Controller  8 , clamp assembly  2 , and orient gear assembly  6  to feed buttons through the flexible track  60  to the chute assembly  4 . 
     When the gear housing  62  is tilted away from the button path  44 , the time required for the orient gear assembly  6  to return, drop, and engage and orient the next button is sufficient to allow the sewing head to attach the positioned button to the article being sewn before the next button is advanced to the sewing position. A thread wiper, as commonly known in the art may be used, preferably anchored to the sewing head upper arm, to clear thread following the sewing the positioned button. 
     Having thus described the invention in connection with the preferred embodiments thereof, it will be evident to those skilled in the art that various revisions can be made to the preferred embodiments described herein without departing from the spirit and scope of the invention. For example, working fluid other than compressed air may be employed with appropriate valves; electronic or other power means may be used to provide a motive means as required to orient, advance, and tilt; and configuration of parts and assemblies may differ from the preferred embodiment and the illustrations herein. It is my intention, however, that all such arrangements, revisions and modifications that are evident to those skilled in the art will be included within the scope of the following claims.