US1319740A - Strom - Google Patents

Description

C. A. WICKSTROIVI.

AUTOMATIC SCREW ASSEMBLING MACHINE.

APPLICATION FILED JAN. 25. 1917.

1,3 1 9 ,740. Patented Out. 28, 1919.

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I W i I 5 III/IIIIIIII/Il C. A. WICKSTROM.

Patented Oct. 28,1919.

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we]??? Charles/i. W/c/fs fjgfi C. A. WICKSTROIVI.

AUTOMATIC SCREW ASSEMBLING MACHINE.

APPLICATION FILED JAN. 25. 1911. a

1 ,3 1 9 ,740. Patented Oct. 28, 1919.

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CHARLES A. WIOKSTROM, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW Y RK, If. Y., A CORPORATION OF NEW YORK.

- A.UTOMATIC scnnw-nssnmnnme MACfiINE.

Specification of Letters Patent. 3 Patented0ct28. 1919. I

Application filed January 25, 1917. I Serial No. 144,342.

To all whom it may concern:

Be it known that 1, CHARLES A, WIQK- sTRoM, a citizen of theUnited States, reslding at Chicago, in the county of Cook and State of Illinois, have invented certain'new and useful Improvements in Automatic Screw-Assembling Machines, of whlch the following is a full, clear, concise, and exact description.

This invention relates to automatic screw assembling machines and more particularly to a machine of this kind which will automatically drive round and oval headed machine screws into. holes tapped to receive 1 said screws. Y

Screw assembling machines are well known in the art and very satisfactory results have been obtained with such machines in driving the ordinary forms of wood screws. When it is attempted to automatically drive machine screws, however, operating difliculties are encountered in properly centering the screws which materially reduce the efficiency of the machine.

It isafn object of this invention to provide an improved round and oval automatic screw assembling machine in which automatic means are provided to guide the screws into proper alinement with the holes tapped to receive them.

Another object resides in improved screw driving means which permits and facilitates alinement of the screws with respect to the tapped holes while they are being rotated by said screw driving means.

A further object consists in improved means for feeding the screws to the driving mechanism and in an improved screw driver controlling means.

' With these and other objects in view, the invention consists of the improved mechanism hereinafter described and more specifically pointed out in the appended claim.

The inventionis illustratedin the'accompanying drawings in which:

Figure 1 is a front elevation of the complete machine;

Fig. 2 is a section on the rinse-2 of Fig. 1 looking in the direction of the arrows with the screw driver feeding mechanism in its normal position; i

Fig. 3 is a fragmentary section of Fig. 2 with the feeding mechanism inits operative position;

Fig. 4 is a section on the line HofFig, 2 looking in the direction of the arrows ,Fig. 5 is a section on the line 55 of Fig;

1 looking in the direction of the arrows;

Fig. 6 is a vertical section through the median plane of the screw driver inclosing case with the screw driver partially' retracted; v I Fig. 7 is a similarview with the'screw driver in its forward position; 4

Fig. 8 is a detailed 'enlargedview of the screw driver operating cams and their associated levers; I

Fig' 9 is a fragmentary section of the screw hopper feeding mechanism;

Fig. 10 is a section on the line 10-1O of Fig. 9 lookingin rows, and Fig. 11 is Fig. I looking in the direction of the an rows. j

Although the preferred embodiment" of the invention herein described consists of a screw assembling machine designed to antomatically assemble machine screws in small metal plates which are used as terminal plates in practically all types of electrical apparatus, said plates being'au-tomatically fed to the screw driver mechanism, the invention is not limited to this specific form or application.

The operating'elements of; the machine are mountedon a cast machine base which comprises the bed 10 and the cast web'll fita section oii-the line 11-11 of the direction of the ar.

so- A ted with a circumferential stiffening rib 12.

Secured to the machine base is a second casting 13 which-carries a screw hopper and I the associated screw feeding mechanism as well as the rotating and reciprocating elementsv 1 of the screw driver proper. The screw .hopper, from which the screws are fed to the machine, consists of a frusto conical sha ed chamber 15 closed at its small end, an secured to rotate with a shaft 130, as will be hereinafter described. The shaft 130 is rotatably mounted ina bearing sleeve 4. Formed integrally with the sleeve 4 is a plate 5 which closes the front end of the chamber 15 and to which issecured afeed chute 16 which opens into'the chamber 15 through a passage 6 in the plate 5. A flange .14 on the plate 4 extends over the end of the chamber 15 and has secured to its inner surface by means of screws 7 7 a ring 8.

ever, due to the movement of the rocker arms 74 and 75,,the link 78 is turned about its pivot 80 against the tension of the spring 82 so that the finger 83 will rest against the shank of the next to the last screw in the chute 20, thereby preventing the movement of the screws in the chute, and the link 79 will be rotated about'its pivot 81 against the tension of the spring 83, thereby removing the bifurcation 85 from the shank of the screw 86 which will consequently be deposited in the chute 87 and fed to the screw driver. The links 78 and 79 are then returned to normal, as hereinafter described, and their movement is so. timed that the bifurcation of the link 79 will straddle the opening of the chute 87 and extend the chute 20 by said bifurcation before the link 78 has been returned to a position'to allow the screws in the main part of the chute 20 to move forward and push the lastscrew in the chute 20 over the opening in the chute 87.

As illustrated in Figs. 6 and-7, the screw driver proper 90 is equipped with a tapered end 91 to secure said screw driver to the spindle 49. The other end of the screw driver isfitted with a frusto conical shaped opening 92, the large diameter of said opening being somewhat larger than the maximum diameter of the screw head. Fitted about said screw driver is the inclosing hood 93 which carries the screw chute 87. This hood is secured to a portion of the main casting 13 by means of the holding stud 96.

Secured to the inclosing hood 93 and pivoted at 100 and 101 are the screw retaining members 102 and 103 which are fitted with the inclined end surfaces 104 and 105. The screw retaining members 102 and 103 are held together by the spring 106. )bv1ously, as shown in Fig. 6, when a screw 15 released into the chute 87 it will be drawn down said inclined wall.

.proper alinement chute by gravity andlodged between the inclined members or jaws 10 1 and 105 of the screw retaining members 102 and 10 3. However, when the screw driver proper is advanced, it will strike against the inclined surfaces 104 and 105 and spread them 9. art against the tension of the spring 106; w 1le the frusto conical opening 92 in the screw driver will engage the head of the screw 110, and the frictional contact between the conically formed walls of the open1ng'92 and the head of the screw 110 will be sufficient to turn said screw and drive it nto the thread tapped hole in a plate 111. Smce the head of the screw 110 is engaged for 1ts entire circumference by the inclined conical wall of the opening 92 of the screw drlver 90, the screw if not properly centered with respect to the tapped opening in the plate 111 will readily right ltself into true and by slippage which Wlll cc cur between the head of the screw and said This adjustment is very driver, which permits the screw to move freely and readily adjust itself to the threads tapped in the hole in the plate 111, makes the automatic driving of machine screws successful, which object cannot be obtained with a blade screw driver which engages and drives the screw by means of the slot in the screw head.

The parts 111 into which the screws are driven are placed in proper slots in a turn table 112 secured to a shaft 113. Rigidly fastened to this shaft is a sleeve 114 whichcarries a ratchet wheel 115 with which cooperates a pawl 116. The pawl 116 is attached to a link 117 which in turn is rigidly secured to a link 118 which is pivoted at 119 and secured to the link 120. The link 120 is driven by a heart-shaped cam 121 to which is rigidly secured a worm wheel 122 driven by a worm 123 attached tothe shaft 24. The ratio between the worm 123 and the worm wheel 122 is the same as that between the worm 30 and the worm wheel 31, and consequently the cam 121 will make a single revolution for each revolution of the cams 33 and 34. Each revolution of the cam 121 will reciprocate the pawl 116, thereby advancing the turn table 112 and submitting a new part 111 to the screw driver.

Any suitable means may be adopted to feed the parts to the screw driver, but in the preferred embodiment of the invention herein described the turn table 1 12driven by the ratchet and pawlmechanism contains a series of slots into which the parts can be readily placed and automatically presented to this screw driving mechanism for each reciprocation of the screw driver, the turn table 112 being built to accommodate alarge cured to the shaft 130, to which the hopper is fastened by means of the hand nut 131. the operation of the machine the screws garetpromiscuously' dumped into the hopper strum the chute 16, from which they are automatically fed into the chute 20 with their shanks held between the Walls 21 and 22 thereof. From the chute 20 the screws are fed one at a time,into the chute 87 which guides the screws into the position between operating elements of the machine in the positions which they assume when the screw driver shaft is in its extreme upward position and a screw has been fed into position between the holding members or jaws 104 and 105 ready to be. driven into the plate 111. A screw held in this position is driven into the plate 111 by the screw driver under the 'sociated lever mechanisms and the "pulleys 35 and 40 and the coiiperating belt 36. T e pulley 40 which rotatesthe screw driving mechanism is continually rotated when the machine is in operation by the main power shaft 24 through the agency of gears 25 and 26, the pulley 35, the belt 36, and the 00'- operating idler pulleys hereinbefore described.

The rotationof the shaft 24 is also transmitted to the worm wheel 31 which rotates with it the cams 33 and 34. The cam 33 controls the reciprocating motion of the screw driver and is shown in Fig. 1 in the position it assumes at the time that the screw driving element is about to move down. Thus when the cam 33 is rotated in the direction shown by the arrow in Fig. 1 the roller 41 will ride down the inclined surface of the cam, due to the action of a spring 132 secured to the lever arm 44, said lever carrying with it the collar 48 attached to the screw driver, shaft or spindle 49. When the roller 41 reaches the lowest position of the cam surface 33 it will then ride up the inclined surface to the uppermost portion of said 7 cam surface, which action through the agency of the associated lever movement will carry the spindle 49 and-its associated screw driver back to its uppermost posit on. Since the spindle 49 is continually rotating durin this reciprocation, the screw driver 90 W11 drive the. screw held between the members 104'and 105 into the plate 111.

This movement of the collar 48 will also rock the arm 56 about its pivot 57 which in turn will move the associated link 58. In the downward movement of the'collar 48 the link 58 will be carried up' and ride over the pin 70, the. weight of the link being thereby dropping said link so that the shoulder 69 rests against said pin. The return movement of the collar 48 will cause a downward movement of the link 58 through the agency of the link 56, and since the pint70 "is held against the shoulder 69, the rocker arms 74 and 75 will move forward and displace the links 78 and 79 against the tension of the springs 82 and 83 and feed a control of the cams 33 and 34 and their aslever 42 returns'to the highest peripheral position on the cam 33 it will ride on this suflicient to rotate/it about the pivot 55 spindle 49 of the screw driver is returning to its uppermost position, this screw will be fed to the members 104 and 105 immediately after the screw previously held by these members has been driven into a blank such aslll. The movement of the lever or link 56 will also reciprocate the connecting rod 126 which will advance the ratchet wheel 128 associated with the hopper one tooth, thereby agitating the screws contained within said hopper. I

When the roller 41 associated with the surfacewithout any movement of the lever 42 through anarc of approximately 160 degrees. During the period that the roller 41 is riding over this portion of thecam, the roller 60 associated with the lever 61 will ride over the raised portion of the cam 34. This will move the lever 61 forward about the-shaft 62 and will carry with it-the levers or links 63, 64, and 65. As the lever 65 is rigidly secured to the shaft .66, this forward movement of said lever will rotate said shaft, said shaft carrying with'it in this movement the pawl 67. This movement of the pawl 67 will cause it to movein the path of, the pin 68secured to the lever 58,.and since the lever 58 is loosely connected to the lever 56 itwill turn about the pivot 55, which movement will shift the shoulder 69 out of the path of the pin 70 and thereby return to normal under the action 'of the spiral-spring 59 the rocker arms v74 and 75 and the mechanism controlled thereby. This will return'all the operating elements of the machine to the positions in which they are shown "in Fig. 1, and the operation of driving the next screw which is held between the members 104 and 105 is repeated, as immediately ,hereinbefore described.

During the period that the worm wheel 31 and the associated cams 33 and 34 are making one revolution, the worm wheel 122 is likewise making one revolution and its associated cam 12]. will actuate the ratchet and pawl mechanism associated therewith, hereinbefore described, and advance the turn table 112 so-as to position another blank 111 under the end of the next screw held between the members means 105.

' The methodpf' driving oval and round headed screws by frictionalcontact between.

the screw head and the inclined walls of] receive said screw threads. This stripping 13 0 is avoided because the'screws tend to right themselves and place themselves in proper alinement by slight movement of the head of the screw on the walls of the opening 92 even though the screws are somewhat out of alinement when the screw driving action is first started. Since the possibility of stripping screws is extremely remote, the screw driving machine requires very little attention and is consequently operated at high efiiciency and low cost. a

Obviously the invention is not limited to the specific embodiment herein illustrated and described, but is capable of many modifications and applications without departing from its spirit and scope, as pointed out in the following claim.-

What is claimed is:

In a screw assembling machine, the combination with a hopper into which the screws are dumped romiscuously, a chute cooperating with said hopper, automatically operated means to feed said screws from said hopper one at a time to said chute the shanks of said screws being held between the side walls of said chute, a screw driving mechanism, cam

and lever operated means for-reciprocating said mechanism, means to rotate said mechanism, a screw holding means comprising a pair of spring operated jaws between which the screw is suspended. by its head and which is adapted to hold said screw for said driving mechanism, camand lever operated mechanisms adapted to feed the screws from said chute to said holding means one at a time, a turn table intermittently operated to present a blank for a screw under said screw driving mechanism for each reciprocation of said mechanism, means operated to spread the jaws of said holding means on the downward stroke of said driving mechanism, and a conically shaped driving head cooperating with said driving mechanism which engages the head of said screw and drives it by the frictional contact between said driving head and said screw head, said driving action also serving to adjust said screw. and drive it straight.

In witness whereof, I hereunto subscribe my name this 18th day of Jan. A. D. 1917.

enannns A. WICKSTROM.

i l I LEAF/3

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