US2554732A

US2554732A - Screw driving machine

Info

Publication number: US2554732A
Application number: US708237A
Authority: US
Inventors: Thomas J Doyle
Original assignee: TUBULAR RIVET AND STUD Co
Current assignee: TUBULAR RIVET AND STUD Co
Priority date: 1946-11-07
Filing date: 1946-11-07
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

May 29, 1951 T. J. DOYLE SCREW DRIVING MACHINE Filed Nov. 7, 1946 5 Sheets-Sheet 1 mp I .7

INVEN TOR. 7Zamaa 1/ pay/e BY 'vmue HTTOENE') y 9, 1951 T. J. DOYLE 2,554,732 I SCREW DRIVING MACHINE Filed Nov. 7, 1946 5 Sheets- Sheet 2 I O lllO x 55 E t I {1 l I I 32 i ll 1 ll 32*? l l" Fi i I m till I INVENTOR.

y 9, 1951 T. J. DOYLE 2,554,732

SCREW DRIVING MACHINE Filed Nov. 7, 1946 5 Sheets-Sheet 3 1 I 54 l h 76 I l I l i F 52 INVENTOR.

: i 720/2941 J flg/e BY I2 d-M WMQ May 29, 1951 T. .1. DOYLE SCREW DRIVING MACHINE 5 Sheets-Sheet 4 Filed NOV. 7, 1946 INVEN TOR. flamai: 0 /6 ,4 Tree/YE) May 29, 1951 T, J, DYLE 2,554,732

SCREW DRIVING MACHINE Filed Nov. 7, 1946 5 Sheets-Sheet 5 INVENTOR. 7300M: dfigy e BY Qua-Qua Patented May 29, 1 951 2,554,732 S RE DR Thomas J. Doyle, Milton, Mass, assignor to Tubular Rivet and Stud Company, Quincy, Mass, a corporation of Massachusetts Application Novembe 7, 1946, Serial No. 708,237 4 Claims. (01. 1441-32) This invention relates to a screw drivin machine.

The invention has for an object to provide an automatic screw driving machine of novel and improved construction, and which is capable of automatically feeding successive screws from a bulk supply and screwing them into threaded holes in the work in a rapid, positive and efficient manner.

With this general object in view, and such others as may hereinafter appear, the invention consists in the screw driving machine and in the various structures, arrangements and combinations of parts hereinafter described and particularly defined in the claims at the end of this specification. I

In the drawings illustrating the preferred embodiment of the invention, Fig. 1 is a perspective view of a screw driving machine embodying the present invention; Fig. 2 is a side elevation of the same; Fig. 3 is a bottom view of a work holding fixture adapted for use with the present screw driving machine; Fig. 4 is a front elevation of the screw driving machine; Fig. 5 is a plan view detail of a connecting element to be referred to; Fig. .6 is a side elevation as viewed from the-left in Fig. 4 illustrating the screw releasing mechanism embodied (in the" present machine; Fig. ,7 is ,a plan View of an adjustable bearing unit for the rotatable and vertically reciprocal spindle and associated parts to be described; Fig. 8 is a cross sectional view taken on the line 8,-8 of Fig. '7'; Fig. 9 is a cross-sectional View taken on the'line 99 of Fig. 8; Fig. 10 is a sideelevatiojn,

in cross section, of the screw supporting jaws;

Fig. .11 is a plan view of a modified form of mounting for the air cylinder, to be referred to; and. Figs. 12', and 13 are front and side elevations respectively of the same.

In' general, thepresent invention contemplates a screw driving machine of novel and improved construction, preferably having a relatively long rotatable and vertically reciprocating spindle having a screw driver bit mountedupon the lower end thereof. guiding the spindle and the parts associated therewith adjacent its lower end in a manner such as tomaintainthe screwdriver bit carried thereby in a substantially fixed vertical axial path during its reciprocation wherebytoprevent deviation'from said path during the rotary movement of thespindle.

Difficulty has been experienced in the' prior screw driving machines of the same general type because. of the tendency of l the relatively dong Provision is made for positively and depending spindle to deviate from a true axial position during its rotation, thus eifecting a gyrating or 'wobbling motion of the screw driver bit which is detachably secured to the lower end of the spindle, so that engagement of the bit with the slotted head of the screw was rendered diflicult, particularly when a relatively small diameter screw was to be driven into the work. In accordance with one feature of the present in vention a bearing member is provided for the lower end or bit holding portion of the spindle and provision is preferably made for adjusting the bearing member in any direction radially or laterally of the spindle to dispose the samein a true vertical axial position and to maintain the spindle and the bit carried thereby in such po sition, thus assuring that the bit will engage with the slotted head and will be maintained in a substantially central position in the slot during the screw driving operation.

Provision is also preferably made in the present screw driving machine for supporting 'the screws in a vertical position in alignment with the spindle; for automatically reciprocating the spindle; and for automatically feeding and releasing successive screws intooperative position with relation to the screw driver bit in'tiihed relation to the reciprocation of the spindle.

Referring now to the drawings, lli'represents a vertically reciprocable and rotatable' spindle supported and journaled adjacent its" upper end in a bracket i2 secured to a column"! upstan'd ing from a base member I6. As herein shown, the vertically reciprocal spindle I0 is arranged to be rotated by an electric'motor 18' through connections including a belt and pulleydriveffi in the usual manner. As herein shown, the elec- -tric motor may be controlled by' a switch 2| mounted in a convenient position on the :frarh e of the machine.

The lower end of the spindle i0 is provided with a clutch member indicated generally at'ZE secured thereto, as by a pin 24, 'and with a bit holder indicated generally at 26 forming apart of the clutch unit. The bit fholder'fi is arranged to detachably receive a screw driver bit 28. The clutch unit 22 is in axial alignment with the-spindle and forms in effect a continuation of the spindle l9 and, as herein shown,-is' vertically slidable in an adjustable bearing unit, indicated generally at SQ, supported in a bracket 32secured to and extending fromthe column l4. *Inorder to support a screw to .bedrivetn, in a vertical position and inv alignment withthe screw driver-bit, a pair of separable jaws are provided,

each jaw comprising a half section 34, 33 shaped to form a socket 38 in which the screw is re ceived, as best shown in Figs. 8 and 10. The jaw members 35, 36 are secured to similar spring arms 46 attached to the lower end of the clutch bearing unit 33. As herein shown, the lower end of the bearing unit is provided with grooves 42 into which the ends of the spring arms are fitted and the arms are secured in a manner such as to permit them to be spread apart by screws Ml which extend through clearance holes in the arms and are provided with coil springs 45 interposed between the arms and the heads of the screws, as clearly shown in Fig. 10.

The screw holding socket 38 formed by the

jaw sections

34, 36 terminates in a beveled countersunk portion against which the end of the screw rests and which communicates with a smaller diameter opening 46 extending to the end of the jaw sections. Thus, in operation, when the bit 28 is caused to descend into engagement with the screw, continued downward movement thereof effects spreading apart of the spring jaws by virtue of the engagement of the end of the screw with the beveled portion, and the yieldable engagement of the jaws with the leg or shank of the screw serves to guide the screw in a vertical position until the screw is engaged with the part into which it is to be screwed, herein illustrated as a nut 48 supported in a work holder or fixture 59. Thereafter, the jaws are further spread apart by the engagement of the head of the screw with the beveled portion to permit the head to pass through and upon seating of the screw in the work the bit 28 is retracted and the jaws again close together in position to receive a succeeding screw. It will be seen that during the spreading operation, the spring arms 4!! are caused to pivot at their extreme upper ends, being yieldingly retained in the grooves by the spring and screw connection and guided between the edges of the grooves.

The work holder or fixture U, herein illustrated merely as an example of a supporting member for the work, is arranged to rest on a table 52 extending from and supported for vertical adjustment on the column [4. In order to align the work with the screw, the table is provided with a locating pin 54 extending upwardly therefrom, see Fig. 1, arranged to cooperate with a grooved portion formed in the bottom of the fixture, as shown in Fig. 3. The illustrated fixture 58 is arranged to support two spaced nuts 48 and the bottom groove comprises an entrance opening 56 and a communicating straight portion 58 terminating in closed ends concentric with the openings in the nuts supported in the top of the fixture. In use, the operator may slide the fixture to cause the locating pin to successively bear against the closed ends of the groove to align the nuts with their respective screws.

The spindle It may be manually reciprocated in the usual manner by a handle 60 attached to a horizontal shaft 62 which is provided with a gear 64 arranged to cooperate with a rack 66 formed on the vertically slidable and nonrotatable spindle bearing member 68 supported in the bracket I2, or, as herein shown, provision may be made for automatically reciprocating the spindle through connections from a double acting air motor of the piston and cyland The air motor is provided with a piston rod 12 which is connected to a rack 14 slidingly mounted in a bearing member or rack guide 16 carried by the horizontal shaft 62, the rack being arranged to cooperate with a gear 18 fast on said shaft. As shown in Figs. 4 and 5, the connection between the piston rod I2 and the rack 14 is designed to permit a floating action in order to prevent binding of the parts and includes a pin carried by the rack and provided with a laterally extended rectangular head portion 82 arranged to fit in a vertical groove 84 formed in an adaptor 86 secured to the end of the piston rod. The pin 86 is rotatably mounted in an upper extension 38 of the rack and the head 82 of the pin is slidably movable both laterally and longitudinally within suitable limits in the groove 84 so that in operation any deviation of the parts from a straight or parallel path is compensated for by the relative movement of the head of the pin in the groove 84.

As illustrated in Figs. 1 and 2, the double acting air motor 10 is provided with a control valve H having a valve pin 13 arranged to be depressed by a trigger '15 forming part of an arm 11 pivoted at 19. The arm 1'! may be connected by a link or chain 8| to a foot treadle 83, and the valve may be connected to a suitable source of air by a connection to the inlet of the valve. Thus, in operation, when the operator steps on the treadle 83 the piston rod 12 is advanced to rotate the horizontal shaft 62 in a direction to effect the downward or operating stroke of the spindle Ill, and when the treadle is released the piston rod is retracted to elevate the spindle.

Provision is also made in the present screw driving machine for automatically feeding the screws in proper arrangement, with the heads of the screws all pointing in the same direction, and for releasing successive screws into the

jaws

34, 36 in alignment with the bit 28 in timed relation'to the vertical reciprocation of the spindle I0. As herein shown, the screws are fed from a rotary hopper 90 of any usual or preferred design arranged to discharge the screws into a chute 92 with the heads of the screws guided between spaced rails 94, 9E and an upper rail 97 of the chute and with the shanks of the screws extended outwardly. The illustrated feeding hopper 90 includes an inner rotary member, not shown, attached to a central shaft 98 and which is arranged to pick up the screws within the hopper and to carry them into alignment with a discharge opening where they are discharged into the chute 92 or rejected according to the disposition of the particular screw. The shaft 98 is arranged to be rotated to effect discharge of the screws from the hopper by a pawl and ratchet mechanism I00 connected by a link I02 to a crank I04 fast on an extension of the horizontal shaft 62, so that, in operation, each time the spindle H) is reciprocated, rotation of the feed hopper shaft is effected.

Referring now particularly to Figs. 6 and 8, the lower end of the chute 92 is arranged in alignment with the

screw holding jaws

34, 36, the latter being formed to permit a screw released from the line in the chute 92 to fall by gravity into the socket 38 formed by the jaws. As herein shown, the jaws are shaped to provide an opening I06 therebetween forming a clearance for the right position, and the jaws are further provided with a curved or cut out portion forming shoulders I08 in alignment with the rails 94, 9B and upon which the head of the screw is supported during the passage of the shank through the opening I05. In operation, the released screw passes beyond the opening I06 and across the shoulders I 08 to come to rest in the socket 33 in a vertical position, as shown in Fig. 8, in alignment with the bit 28 and with the end of the screw resting on the beveled portion at the bottom of the socket 38.

The releasing mechanism, indicated generally at III), is designed to release successive screws from th line in the chute 92 in timed relation to the operation of the machine and, as illustrated in Figs. 4 and 6, the releasing mechanism includes a laterally movable escapement or cutoff member I I2 slidably mounted in a grooved portion of the chute supporting bracket I Hi. Ihe laterally movable cut-off member H2 is bent, as shown in Fig. 6, to extend around the underside of the chute and is provided with spaced escapement arms H5, IIB forming a passageway I therebetween. In operation, when the cut-ofi member II2 is moved to the left, as shown in Fig. 6, the foremost screw rests against the upper arm I I6, and when moved to the right the foremost screw is permitted to fall by gravity through the passageway I28 and against the lower arm I I8. Thereafter, in the operation of the machine, when the escapement member is moved to the left the screw on the lower arm is released to fall by gravity into the socket 3B of the screw supporting and guiding jaws, the following screw being held back by the upper arm M6 to be released during a succeeding cycle of operation.

As shown in Fig. 6, the escapement member I I2 is arranged to be moved laterally in timed relation to the reciprocable movement of the spindle II] by a cam I22 fast on the horizontal shaft 62 and through connections including a two-armed lever pivotally mounted at I24, one arm I26 of which is arranged to bear against the cam I22. The second arm I28 of the two-armed lever is provided with an extension I30 arranged to extend into a pocket formed between a side wall of the escapement member and a bent up or hooked portion I 32 thereof. As herein shown, the extension ISII is pivotally connected to the arm I28 and the latter is provided with a leaf spring I34 arranged to bear against the extension, and an adjustable stop screw I36 also is arranged to engage the extension whereby to adjustably limit the movement of the extension in one direction and to permit yielding of the extension when moved in the opposite direction. A pivotal latch I3! may also be provided to engage the escape.-,.

ment member when it is desired to discontinue the automatic feed of the screws. A spring I39 is connected to the arm I28 to hold the arm I26 against the cam.

From the description thus far it will be observed that in the operation of the machine the operator places the fixture 50 on the table 52 to present a nut 48 in alignment with th spindle, guiding the fixture by the locating pin 54. Thereupon, the foot treadle 83 is depressed to effect a downward stroke of the rotating spindle It, the bit 28 engaging with the slot in a previously released screw and forcing the screw downwardly between the holding and guiding jaws 34, to engage the end of the screw with the nut 48, the head of the screw passing beyond the ends of the jaws during the driving operation. Upon driving of the screw into the nut held by the fixture, the operator releases the treadle 83 to effect elevation of the spindle I0 whereupon the jaws 34, 336 spring together to receive a succeeding screw released by the escapement member II2 during the elevating stroke. The operator may then move the fixture to present the second nut in alignment with the succeeding screw and the operations are repeated.

The clutch unit 22 may be of a standard type having separable clutch members which are held apart or disengaged by gravity, that is the lower clutch member to which the bit is attached is free of the upper member until the bit engages the head of the screw whereupon the lower clutch member comes to rest and is gradually engaged by the upper clutch member a it descends. During this time, the bit in engagement with the top of the head of the screw finds the slot and upon full engagement of the clutch members the screw is engaged with and driven into the nut, as above described. The clutch unit may and preferably will also be provided with a slip connection, not shown, arranged to release the driving connections upon full seating of the screw in the nut, as is well known in the art.

Provision is also preferably made for positively limiting the downward stroke of the spindle I 0 and, as herein shown, the lower end of the vertically reciprocal bearing member 63 is provided with a clamp I40 movable therewith and having an extension I42 to which an upstanding threaded rod I 34 is attached. The rod is flatted on opposite sides tov pass between a fixed yoke member I 36 extending from the bracket I2, the yoke forming a vertical guide for the threaded rod I44 and preventing rotation thereof. A tubular member I43 placed over the rod and resting on. the top of the fixed yoke member I56 is arranged. to be engaged at its upper end by adjustable check nuts I on the rod to effect stopping of the spindle at a predetermined point in its down-- ward movement.

Referring now particularly to Figs. 6, '7 and 8, the adjustable bearing unit 38 for the spindle extension, comprising the clutch unit 22, which carries the screw driver bit 2t is arranged to be adjusted laterally to align the spindle and the clutch unit in a vertical axial position and to maintain the parts in such position during the screw driving operation and, as herein shown, the bearing unit includes an elongated bearing member I66 of rectangular shape in transverse cross section and which is provided with an axial bore I62 arranged to slidingly receive the clutch unit 22 for vertical reciprocation therein. The rectangular bearing member IE6 is provided at its upper end with an annular portion i6 3 arranged to be fitted into a cylindrical opening in an adjustment plate I 66 secured to the toppf the bearing member by screws I53, as shown in Fig. 7, and the lower end of the bearing member is provided with a cap member I681; having a clearance hole I15 for the bit holding portion 2b and to which the spring arms 45] are attached.

As illustrated in Fig. 8, the laterally extended portions of the adjustment plate it rest upon the top of a U-shaped extension I72 of the supporting bracket 32. The extension IE2 is provided with a. rectangular cut out portion or slot I74 arranged to receive the rectangular shaped depending bearing member I60 for lateral adjustment therein, the cut out portion I'M being slightly larger than the dimensions of the hearing unit. The plate I66 is adjustably secured to the top of the U-shaped extension by screws I16 which extend through clearance openings I18 in the plate and into tapped holes IS!) in the supporting bracket, the clearance openings being sufiiciently large with relation to the screws I16 to permit lateral movement of the adjusting plate. Thus, in operation, when assembling the unit, the bearing member I80 may be moved in any direction laterally or radially within the limits of the clearance openings for the screws and the clearance between the walls of the extension I12 and the bearing member whereby to effect alignment of the clutch unit 22 for the purpose described, and the screws I16 may then be tightened in place to maintain the parts in their aligned position.

Referring now to Figs. 11, 12 and 13, as therein shown, a modified form of the invention may include an individual mounting for the air motor '18 capable of adjustment for aligning the air motor with relation to the rack and pinion drive 14, 1B, and which also provides a structure by which the air motor may be conveniently removed or replaced in the machine. As herein shown, the air motor may be mounted on a bracket I82 adjustably clamped to the column I9 and which is provided with a supporting plate I84 arranged to receive angle brackets I86, I88 by which the air cylinder unit is supported.

The air motor 10 is provided with a plurality of elongated bolts I99 threaded at their ends and which extend through the end cap members of the air cylinder and are provided with nuts I92 for clamping the cap members to the cylinder. The angle brackets I86, I83 are arranged to be received by the two lower bolts I98 and are secured to the cylinder unit by the nuts I92. The base legs of the angle brackets I86, I88 are provided with slotted openings I94 arranged in alignment with holes in the supporting plate I84 and the angles are attached to the plate by bolts and nuts I96, I98.

From the above description it will be seen that in operation the supporting bracket I82 may be adjustably moved both vertically and rotatably on the column I4 to dispose the air cylinder unit 19 at the proper height and in substantially parallel arrangement with relation to the gear and rack '14, E8. In order to align the air cylinder unit 19 in operative relation to the gear and rack for most efficient operation, the unit may then be adjusted laterally on the supporting plate I84 by virtue of the slotted openings I94 in the angle brackets, thus providing in efiect a universal adjusting structure for aligning the air motor in parallel alignment with the rack and pinion and also providing a separate mounting for the air cylinder to facilitate assembly thereof in the machine.

While the preferred embodiment of the invention has been herein described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:

1. In a screw driving machine, in combination, a rotatable and vertically reciprocabl spindle, a bit holder carried by said spindle, supporting means cooperating with the spindle adjacent the bit holder for preventing lateral movement thereof during vertical reciprocation, and means for supporting a screw in vertical alignment with said bit holder including a pair of separable spring pressed jaw sections arranged to yieldingly spread apart to eject and guide the screw to the work upon downward pressure of a bit held in said bit holder during the screw driving operation, a work supporting table having a locating pin upstanding therefrom and disposed in alignment with the bit, and a work holding fixture having recessed portions in the underside thereof for cooperation with said pin to align the work with the screw and the bit.

2. In a screw driving machine, in combination, a rotatable and vertically reciprocable spindle, a bit holder carried by said spindle, supporting means cooperating with the spindle adjacent the bit holder for preventing lateral movement thereof during vertical reciprocation, and means for releasably supporting a screw in vertical alignment with said bit holder, a work-supporting table having a locating pin upstanding therefrom and disposed in alignment with the bit, and a work-holding fixture having recessed portions in the underside thereof for cooperation with said pin to align the work with the screw and the bit.

3. In a screw driving machine, in combination, a rotatable and vertically reciprocable spindle, a bit holder carried by said spindle, supporting means cooperating with the spindle adjacent the bit holder for preventing lateral movement thereof during vertical reciprocation, and means for releasably supporting a screw in vertical alignment with said bit holder, a work-supporting table having work-indexing means thereon, and means for laterally adjusting said spindle to align said bit holder with said work-indexing means.

4. In a screw driving machine, in combination, a rotatable and vertically reciprocable spindle, a bit holder carried by said spindle, supporting means cooperating with the spindle adjacent the bit holder for preventing lateral movement thereof during vertical reciprocation, and means for supporting a screw in vertical alignment with said bit holder including a pair of separable spring pressed jaw sections arranged to yieldingly spread apart to eject and guide the screw to the work upon downward Pressure of a bit held in said bit holder during the screw driving operation, a work-supporting table having work-indexing means thereon, and means for laterally adjusting said spindle to align said bit holder with said work-indexing means.

THOMAS J. DOYLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 950,534 Hunt Mar. 1, 1910 1,624,189 Steen Apr. 12, 1927 1,813,697 Dellaree July 7, 1931 1,816,829 Leeuw Aug. 4, 1931 1,822,692 Leeuw Sept. 8, 1931 1,862,845 Dellaree June 14, 1932 1,984,282 Ray Dec. 11, 1934 2,342,946 Le Tourneau Feb. 29, 1944 2,404,921 Oxsen July 30, 1946