US2657721A

US2657721A - Screw feed and drive mechanism

Info

Publication number: US2657721A
Application number: US204127A
Authority: US
Inventors: Ernest H Shaff
Original assignee: KELLER TOOL CO
Current assignee: KELLER TOOL CO
Priority date: 1951-01-03
Filing date: 1951-01-03
Publication date: 1953-11-03
Anticipated expiration: 1970-11-03

Description

i ..r//l Kil E. H. SHA-FF scmsw FEED AND-DRIVEMECHANISM Filed Jan.

v *Z22-l Nov. 3, 1953 2 HHI l II lll Patented Nov. 3, 1953 UNITED o STATES 'ATENT OFFICE 2,657,721 A .SCREW FEED AND DRIVE MECHANISM ration of Michigan .Application Januarys, 1951, serial No. v204,127

11 Claims. (o1. lv1144-32,)

The invention relates to a feed or delivery mechanism for screws .and like elements, here-- inafter .referred to flor-convenience as screws., and especially adapted :for .use with power operated tools so `as to :expedite the application of the screws to the work. y

.A general object of the invention :is to provide an `improved feeding .mechanism-of .the 'character set forth in which the delivery of screws to a desired .holder v,is utilized -to `govern the operation of the mechanism in feeding additional screws to .such holder. y

Another .object is .to Aprovide a feeding and :delivery :mechanism wherein jas an incident lto the disassociation.ofvonescrewffrom a holder another screw is deliveredthereto. i

kA more specific sobject Ais to yprovide a screw feeding or.de1ivery.mechanism associated directly with a driving tool having a Iiinder :constituting thefscrewholderto ,which-.the screws-are delivered successively. i

v The objects of 4the :invention fthusgenerally set forth `vtogether with -other Yolojects and ancillary advantagesareattained by theconstruction and arrangement shown by way of illustration in` f the. accompanyingdrawing, :in which:

Figure 1 is a fragmentary .elevational View of i While the invention is 'susceptibley of Various modifications and alternativeconstructionaithere is v.shown fin rthe drawing ,and will herein -be L described 4in detail `the l.preferred embodiment, llout itis .to be :understood .that itis 4not thereby-intended' tollimit ',the :invention .to ,thevform dis-` closed", but itis intendedto coverallrnodifications and alternative .constructions falling `withf invrthe ,spirit andsc'openof ,the invention as expressed' in the appendedclaims.

the` pre'sentembodiment ofthe inventiomthe iriiprove'd 'feed `Inechanisml fis .directly associated with' a portable ,pressure `fluid .actuated vvl*sere-w ,naled in a barrel I2 ri themain housing, l,Eiresalire fluid thusfsuppli'ed' is under the conti-clef throttle valve generally A ing 8 having a mtaly @hier 9 therein for driving a Spindle 1 0 thro-ugh the medimn Qi a tomb' ed speed reduction gearing and ,clutch ,mecha Slmgenerally indicated at .l The spindle .l0 15561.51

ward end Aof which is received the shank jof a screwdriver hit :YI-.5.

I6 which is connected to the tool .by means 0f a tting `l1. Ine glatter is received in a lhead 1,8 which, in tuna :serves ,t0 @105e aille vveel I end Qi indicated at I9 in the-tool head lf3 whichds adapting ,8 imposition foriconvenierlt manipulan@ .bv

inthe forward '50 tnerepetween "the ,lingers of an-.qperatcriusilig the i001 ErQm the ivalve L9 p rtesspllre fluid iis conducted to the g motor 9 by way `of zannillar ,Simply ,Chamber 2| surrounding thevalvefland as upply passage In accordance with thepreellv finvellltiQll,

means y"vis v p'rtlvided Afor rsuccessively conveying I Screws .from a ihcppelcr,otherrsupply SQuvCefvQ ,a

suitable holder, which, @aus .lrdlju'ds' aY-releaSe mechanism-operativeiin rfsponseztodisassociation of fa .delivered :Screw .Wllhrespect to .the A holder to release another screwfronilthe hopper. While 4 theholdenmaytake various fprms,inlvhe-r?le$erlv embodiment; it directly associatedwith nthei'tool andiconstitute's aiIlClfPELmQIlBlJQd-Qn the 11.05.@ -of the tool and serving to 3lnQll-a screw `:in r10,051- tion forengagementtby L1 ;iie-Jci;t l5 sotliat itcan be. applied? to a workpiece The .lindergas isllQv/. .includes a eylindrial l 25 and the ba elongated slot 21A forV ed the body! ortion fRefinlnameane the o uterfendfof ,the

toireleasablyelialsl a;

respective onespflongitudinally sl' Desai arcanes viermal ad- .sid with the fdrward @ad 0f :the ymin 'housing ,8- .The ,Spindwhas bare- '4 extending .axially therethroilgh in the .zfv-v e ,negers it?. are :teneinde-ia .i zpelfipl-ierallvieaedvseries of outer end of the body portion 26 of the nder, and the tapered tips 28a of the fingers 28 extend therethrough into the body portion 26 for engagement with the threaded body of the screw SI so as to firmly retain the screw in position in the nnder for application to the work. To prevent longitudinal movement of the fingers With respect to the body 26 each nger is provided with a laterally projecting lug 28h which is received in a recess 3| in the body portion 26 at the upper end of each of the grooves 29.

The lingers 28 are held in place on the nder by a snap ring 32 which surrounds the body portion 26 of the nder and is received in a transverse groove adjacent the inner end of each of the fingers 28. This construction and arrangement permits the ngers to spread radially outward so as to receive a screw therebetween.

In use, the tool is moved so that the screw SI is brought into desired position on a workpiece and upon exerting a slight force in a direction to press the tool against the work the nder 25 is telescoped within the barrel I2 and the bit I is moved into engagement with the head o the screw SI. Thereafter, the clutch II is engaged so that upon admission of pressure fluid to actuate the tool, the screw SI is driven.

In the exemplary form of the invention, aspirator means in conjunction with an escapement mechanism is utilized to successively withdraw screws from a hopper H and to direct them to the nder 25 in position to be driven by the bit I5. As shown, the aspirator means, generally designated 35, includes a tubular element 36 screw threaded into the enlarged upper end of a stepped bore 38 which extends longitudinally through a boss 39 formed integral with the tool head I6 and projecting laterally therefrom. The lower end of the bore 38 is of a diameter somewhat less than that of its upper end, and preferably the two ends of the bore 38 are joined by a tapered wall portion 46. Adjacent its inner end the tubular element 36 is of reduced diameter and at its inner end the element 36 also is tapered as at 36a.

This construction and arrangement denes an annular chamber 42 with a restricted annular outlet 43 to which the pressure fluid is supplied by way of a passage y44 in the tool head I8 :from the valve chamber 2i upon actuation of the valve I9. Passage of pressure uid from the chamber 42 and through its restricted outlet 43, by Venturi action, creates a suction or partial vacuum within the tubular element 36 which is transmitted by way of a exible tube 45 to the escapement mechanism generally indicated at 46. Control of the Venturi action may be eiected by varying the size of the annular orifice 43 between the tapered end of the element 36 of the tapered shoulder 40 in the bore 38. This can be accomplished simply by shifting the element 36 axially in the bore 38 by means of its screw threads. A locking nut 36A is provided to maintain the desired position of adjustment.

To join the tube 45 with the tubular element 36, the upper end of the latter is of enlarged internal diameter to receive the end of the tube 45. Also the upper end of the element 36 is slotted as at 41 and a clamping nut l48 is provided for coaction with the slotted end so as to form in effect a collet for gripping the end of the tube `45 to hold the same in place.

As shown, the escapement mechanism 46 includes a tube 50, a pawl -5I and an actuator 52 for the pawl. The tube 5I) is of generally cy- 4 lindrical form having an inner diameter slightly larger than the diameter of the heads of the screws S. It is received in the outlet of the hopper I-I and to its outer end is secured the upper end of the tube 45.

The pawl 5I has two laterally extending ngers Bla and 5Ib which are spaced apart a distance substantially equal to the length of one of the screws S and which project into the tube 50 through openings 56a and 50h, respectively, therein. r:Che pawl 5I is pivoted intermediate its ends on a lug 53 rigid with the tube 56 for rocking movement to alternately project the ngers 5Ia and 5Ib into the tube 58. The actuator 52 for rocking the pawl 5I is of the pressure-responsive type and includes a push rod 54 connected at one end to the lower end of the pawl 5I, and intermediate its ends the push rod is attached to a flexible diaphragm 56. The diaphragm 56 is disposed within a housing 58 and forms one side of a pressure chamber 59 within the housing. The housing 58 also has a bore 60 in the wall thereof opposite the diaphragm in which the other end of the push rod 54 is guidingly received. Normally the pawl 5I and push rod 54 are maintained in a position such that the lower pawl finger 5Ib is projected through the opening 56h into the tube 50 in position to engage the head of the screw S2 and prevent it from dropping through the tubular element 5I) into the tube 45.

Upon actuation of the valve I9 pressure fluid is admitted to the aspirator chamber 42 by way of the passage 44. By the Venturi action at the orifice 43 a partial vacuum is created which is transmitted to the pressure chamber 59 by way of the flexible tube 45, the tubular element 50 and a tube 5I which is connected at one end to the element 56 and at the other to the housing 58. By thus creating a partial vacuum within the chamber 59 the diaphragm 56 is moved inwardly. Such movement of the diaphragm retracts the push rod 54 and rocks the pawl 5I thereby withdrawing the finger 5Ib to permit the screw S2 to be drawn down the tubular element 50 and the tube 45. When the pawl 5I is rocked the finger 5m is projected into the tubular element 50 beneath the head of the screw S3 to prevent it from following its predecessor down the tube.

Received in the lower end of the bore 38 of the boss 39 of the tool head I8 is a tubular connecting member 62 the lower end of which is telescopingly received in a feeder tube 64. The latter is xed at its lower end to the body portion 26 of the finder 25 adjacent the lower end thereof, and opens into it in angular relation. Interposed between the boss 39 and the upper end of the feeder tube 64 of the finder and disposed about the member 62 is an expansion spring 65 which serves to normally maintain the finder in outwardly telescoped relation with respect to the barrel I2 of the tube.

Pressure fluid from the orifice 43 is directed downwardly through the tubular element 62 and v.the feeder tube 64 and normally escapes through the open end of the body portion 26 of the nder 25. As previously described, the screw S2 is drawn downwardly through the exible tube 45 and into the aspirator element 36 by the partial vacuum or suction created therein. Upon reaching the lower end of the aspirator element 36 the '7 ing a series of peripherally spaced slots therein and ngers resiliently mounted in said slots for holding a screw in position to be driven by the screw driver, and a screw feeding mechanism associated with said finder and operable as an i11- cident to the removal of one screw from the nder to supply another screw thereto in position to be driven, said mechanism including a tubular member connected between said finder and the hop- ;per, an aspirator operatively associated with the pressure fluid supply to the screw driver and with said tubular member and operative to create ya partial vacuum in the latter when said finder body portion is open and operative to create a positive pressure in said tubular member when said finder body portion is blocked by a screw, and means alternately responsive to said vacuum and rpositive pressure to control the release of screws from said hopper for transmittal by way of said tubular member to said finder.

7. For use with a screw driver having connection with a pressure fluid source to actuate the same and including a finder for holding a screw in position to be driven thereby, a screw feeding mechanism for supplying screws one at a time from a hopper to the nder, said mechanism comprising, in combination, a tube opening at one end into the finder and at the other end into said hopper, an aspirator interposed intermediate the ends of the tube and having connection with the pressure uid source, a pressure responsive release means connected with said tube between said aspirator and the hopper, said aspirator being effective upon removal of a screw from the finder to produce a partial vacuum in the portion of said tube adjacent the hopper to actuate said release means so as to release another screw from the container and draw the same through the portion of said tube adjacent the container and the aspirator and thereafter blow the screw into said finder in position to be driven by the screw driver. 8. In a screw driver adapted to be connected to a source of compressed air to actuate the same and to a hopper or the like containing a supply of screws to be driven thereby, the combination comprising, a casing, an air motor within said casing, a bit driven by said motor, a tool head on one end of the casing, valve means including a supply chamber within said tool head for controlling the supply of compressed air to said motor, a finder on the other end of said casing disposed in telescoping relation yto said bit and adapted to hold a screw in position to be driven by said bit, and screw feeding means for supplying screws one at a time for reception in the finder, said means including a pressure responsive escapement mechanism for controlling the release of screws from said hopper, and an aspirator communicating with said valve supply chamber and operative as an incident to the removal of one screw from said finder to actuate said pressure responsive means whereby to release another screw from said hopper.

9. In a screw driver adapted to be connected with a source of compressed air to actuate the same Vand with a hopper containing a supply of screws, the combination comprising a casing, an air motor within said casing, a bit driven by said motor, a tool head on one end of the casing, valve means including a supply chamber within saidv tool head for controlling the supply of compressed air to said motor, a finder on the other end of said casing disposed in telescoping relation to said bit and adapted to hold a screw in position to be driven by said bit, and a screw feeding mechanism for supplying screws one at a time to the finder, said mechanism including a tubular element affording communication between the hopper and said finder, pressure responsive means operatively associated with said tubular element for releasing screws one at a time from the hopper, and means carried by the toolhead and connected with said valve supply chamber and with said tubular element for effecting a pressure differential in the latter upon removal of one screw from said finder to actuate said pressure responsive means to release another screw from said container for delivery through said tubular element to said nder.

l0. A pneumatic screw driver comprising, in combination, a casing, an air motor within said casing, a bit driven by said motor, a tool head closing one end of the casing and adapted to be connected with asource of compressed air, valve means including a supply chamber vwithin said tool head for controlling the supply of compressed air to said motor, a finder on the other end of said casing disposed in telescoping relation to said bit and adapted to hold a screw in position to be driven by said bit, and a screw feeding mechanism for supplying screws one at a time to the nder, said mechanism comprising a hopper for a supply of screws, a tubular element affording communication between said hopper and said finder, pressure responsive means operatively associated with said tubular element for controlling the release of Vscrews from said hopper, and means vconnected with said valve supply chamber and with said tubular element for effecting a pressure differential in the Ylatter upon removal of one screw from said finder to actuate said pressure responsive means to release another screw from said container for delivery through said tubular element to said finder.

1l. A mechanism for effecting the successive delivery of screws or like parts to a predetermined point, said mechanism comprising means dening a delivery passage communicating with a source of air under pressure, and a control device for effecting the movement of'screws one at a time through said passage, said device including an element'responsive to variations in pressure inthe passage, and means affording communication betweensaid element and said passage, said passage having a discharge portion dimensioned with respect to the size of the parts so as to eiect apressure change in the passage dependent upon the presence or absence of a part from the discharge portion thereof.

v ERNEST listings. References Cited in thel fileV of this patent UNITED STATES PATENTS Number .Name I Date 1,703,458 Ruff Feb. 26, 1929 1,980,967' De MooyV Nov. 13, 1934 2,125,249 Temple July 26 1938 2,373,992 Billinghurst Apr. 17, 1945 2,534,140 IMoore Dec. y12, 1950