US2188158A - Screw driver - Google Patents

Description

G. L. ROCK SCREW DRIVER Jan. 23, 1940.

Filed Maron 3, .'1937 3 Sheets-Sheet l 'ANmHI/ll llhuvlj il I x www y 'Gear elLoc/o l @PJ mn. w

Jan. 23, 1940. G, L, ROCK 2,188,158

SCREW DRIVER Filed March 5, 19347 3 Sheets-Sheet 2 4,4 l S Nv ,2m Q Fm 4 .4,4% QN uw .WN e9. MW ,Sw uw W Jan. 23, 1940. G. l.. ROCK SCREW DRIVER Filed March 3. 1957 3 Sheets-Sheet 5 Patented Jan. 23, 1940 UNITED STATES PATENT FFICE 18 Claims.

This invention relates tospiral screw drivers.

Spiral screw drivers-in use today each embody ank exposed longitudinally movable spiral shaft secured-to an operating handle and a'nut or fold lower. secured through suitable instrumentalities to the `screw driverl blade or bit. K For the purpose of lproviding movementin opposite directions, re-

versely directed spirals are cut into the `shaft and mechanism.- is provided-for shiftingthe follower 1.0` from. one groove-to the reverse groove orA to a lockingfposition `between the starting ends of the two l intersecting grooves.

The use of such screw drivers has been limited, andwhen used in high speed orquality work found unsatisfactory, because of` certain inherent defects. AsY the force requiredto move the screw increases there isan increased tendency of the handle to lback-spiral, that is, to turn backwardly upon downward push of the handle, the screw driver bladeconsequently being rotated less and less.` Inorder to prevent this, a force musil be appliedcircuinierentially of the handle suflicient to overcome the backwardtortional thrust-oi` the spiral. These forces, when not in exact balance, produce with the forceexerted longitudinally of the handle, a resultant force which increases to such aimagnitude as to cause the screw driver blade suddenly to slide laterally of, and out of engagement with, the screw head. This, besides being al constant annoyance and causing a loss of time in` all cases, prohibits its-use in house finishing or other work of a decorative character. The necessary film of lubricant on the exposed .spiral keepsy the tool dirty and resultsin. the :$5 spoilation of line work, such as room trim and the like. Also, this film rapidly picks up and retains dirt, gravel, sawdust and the like, requiring relatively frequent disassembling of the tool for cleaning purposes. Another inherent defeet is the rapid deterioration and destruction of, the spiral mechanismcaused by the relatively small wearing surface between operating parts. Objection has also been validly made to. the means provided for controllingthe spiraling action. In order to rotate the screw driver blade directly when the force required `exceeds that which can be transmitted through the spiral. it is necessaryV to remove the tool from the screw, push the spiral to the complete forward'position and manually make a precise adjustment of the .small locking pin that prevents movement of the follower along either. of the two spiral grooves. This is an operation which often results in the annoyance of pinched and lacerated hands and consumes suiicient timel to constitute a matter of considerable importance in high speed or mass production assembly work.

It is the object of applicants invention to provide a spiral screw driver free from the above generally. stated inherent defects.

Specifically, it is an object of this invention to provide, in a spiral screw driver or the like, means to automatically lock the driver bit or work tool tothe handle whenever the force required to move the screw exceeds a predetermined value, said means being operative in all `positions ofthe handle and spiral and being. effective to prevent back-spiraling.

A further object is to provide tortionally actuatedmeans for automatically locking the handle to the driver bit or work tool fory rotation as a unit..

Another object is to provide tortionally actuated means between the driver bit and the'spiral actuating' means for automatically locking the handle to the driver blade for rotation as a unit.

A further object of applicants inventionv is theprovision of a spiral screw driver employing separate and independent spiral members for forward and reverse rotation of the driver bit, thereby elminating cross-overs between the spirals,.and the excessive wear caused thereby.

A further object is the provision of a spiral screw driver having inter-engaging wearing surfacesbetween a spiral member and a follower increased to an extent impossible in previous spiralscrew drivers.

A` further object is' to provide spiral screw drivers in which the spiral members and followers are each' provided with anincreased number of inter-engaging spiral teeth or threads for properly distributing the forces between said members and -said' followers.

Another object of the invention is the provision of more efficient and durable means for connecting a spiral lmember`` to a driver bit for transmitting force in one direction and for permitting full ratcheting in the reverse direction.

A further object is to provide a spiral screw driver with more precise and yet sturdier means forV controlling the forward and reverse movements of the driver bit.

A still further object of applicants invention is to provide a spiral screw driver by which the speed of tightening and loosening screws may be diierent to the end that the initial tightening of the screws may be accomplished at a higher speed than the loosening of the screws for the purpose of shortening the time of placing screws YI in the end IIB of member 6.

while at the same time preventing removal o'f screws at too rapid a rate for safety.

Another object of the invention is to provide a spiral screw driver in which no lubricating surface is exposed; in which the conditions of lubrication are ideal from the standpoint of eihciency and cleanliness, and in which no spiral surface is exposed to pinch o-r lacerate the operators hands.

Other and kfurther objects are to provide a spiral screw driver which, as compared to present day spiral screw drivers, shall be lighter in weight, sturdier and more durable in construction; shorter in length for the same handle,

travel; cleaner to handle, and of an increased range of usefulness.

Other and further objects and advantages. will be apparent from the following detailed description of one illustrative embodiment of the invention, when considered with the accompanying drawings wherein:

Fig. 1 is an elevational view partly in section of a screw driver embodying the invention; f

Fig. 2 is a View partly in elevation and partly in section of the driven end of the screw driver;

Figs. 3, 4 and 5 are views similar to Fig. 2 showing a portion of the mechanism in diierent positions of operation; A

Fig. 6 is a longitudinal section taken along the lines 6 6 of Fig. 1;

, Fig. 7 is a lateral cross section taken along the lines 1--1 of Fig. 6;

Fig. 8 is a transverse cross section taken along the line 8-8 of Fig. 6;

Fig. 9 is a transverse section taken along the line 9 .9 of Fig. 6;

Fig. 10 is a transverse section taken along the line IU--I of Fig. 6;

Figs. 11, 12 and 13 are sections similar to Figs. 8, 9 and 10 but showing the positions of the parts vunder a different condition of operation, and

Figs. 14, 15, 16, 1'7 and 18 are exploded views in perspective of the different parts of the screw driver.

As shown in the drawings, the screw driver embodies a handle I threaded at one end to reoeive a cap screw 2 and centrally bored to receive a shield 3 therein, the shield 3 comprising a cylindrical tube open at one end and having a hexagonal aperture 4 (Fig. 14) in its other end for a purpose later to be described. 'Ihe shield 3 is provided with teeth or projections 5 (Fig. 14) for engaging the material of the handle I when driven thereinto for retaining the shield against movement relative to the handle I. The shield 3 receives a spiral member 6 which is secured thereto against relative rotation. The spiral member 6 comprises a tube having spiral teeth or threads 'I on its outer periphery and internal spiral teeth or threads 8 extending ashort distance inwardly from the end 9 of the tube. The internal diameter of the tube from the opposite end YIll to the internal spiral teeth 8 is equal to the base or root diameter of said teeth as clearly shown in Fig. 15. The end Ill of the spiral member 6 is provided with an opening II to receive the cylindrical end I2 of a stud I3. The cylindrical portion I2 of the stud I3 is provided with `a transverse aperture I4 of the same size and adapted to register with a transverse aperture A collar I6 is adapted to snugly ilt over the end III of the member 6 and the collar is provided with a transverse aperture I1 of the same size, and adapted to register with, the aperture I4 of the stud I3 and the aperture I5 of the member 6. A pin I8 is provided, and this pin passes through the apertures I4, I5 and I1 and secures these parts in assembled relation.

The stud I3 is provided with a hexagonal nut portion I9 of the same size and adapted to register with the hexagonal aperture 4in the end of the shield 3 for the purpose of securing the stud and the attached member 6 to the shield 3. The stud I3 is provided with a threaded portion 2U, which is adapted to receive a washer 2| and a nut 22 for securing the stud and member 6 to the shield 3 against longitudinal movement. The external teeth 1 of the spiral member 6 are adapted to mate with spiral teeth or threads 23 .formed internally of the tube 24 and the internal teeth 8 of the spiral member 6 are adapted to mate with the external teeth or threads 25 of a spiral member 26. The spiral member 26 passes loosely through the tube 24 into mating engagement with the spiral member 6. A nut 21 threaded on the reduced end 28 of the member 26 slidingly engages the inner portion of the tube 6 between the threaded end 9 and the opposite end I IJ and the movement of the member 26 outwardly of the tube 6 is limited by the engagement of the nut with the inner end of the spiral teeth or threads 8.

The tube 24 at its end opposite the spiral 23 is pinned to the hub portion 29 of a ratchet 30 by a pin 3| which passes through the tube and the hub 29. A pressed-fit collar 32 surrounds the end of the tube 24 and the pin 3l. At its outer end, the spiral member 26 carries a similar ratchet 33 and the portion of the member 26 which passes through the central bore of the ratchet 3U is smooth and of slightly smaller diameter than the internal diameter of said ratchet, thereby permitting the member 26 to freely rotate in the opposite direction relative to the ratchet 36. On the tube 24 there is mounted a sleeve 34 having a reduced and externally threaded portion 35. The sleeve 34 abuts the collar 32 and threadedly engages the internally threaded shank 36 of a driven member or sleeve 31. Inwardly of the internal threads the member 31 is provided with a smooth bore 38 which co-operates with the collar 32 to form a bearing for the member 31. Inwardly of the shank 36 the member 31 is provided with a knurled annular flange 39 to permit manual manipulation of the member 31 for purposes later to be described. The member 31 is provided with a reduced portion 4E] inwardly of the collar 39 and the portion 40 connects with a still further reduced portion 4I.

The portion 40 is provided with a longitudinal slot 42 and an aperture 43 somewhat greater in width than the width of the slot 42 and registering with said slot. Longitudinal slots or grooves 44 and 45 are cut into the surface of the portion 4U at right angles to the slot 42 and aperture 43, the grooves 44 and 45 extending to the shoulder 46 formed by the reduced portions 4I and 40. The portion 4I is provided with an arcuate slot or key-way 41 adapted to receive a substantially semi-circular key 48 and at the outer end of the portion 4I is formed a threaded portion 49 of slightly smaller diameter than the portion 4I, and therefore forming with the portion 4I a shoulder 50.

A drive pin or clutch member 5I has a hub portion 52 and an upstanding tooth or lug 53. The hub 52 is provided with a square or rectangular aperture 54 for receiving the squared or rectangular end 55 ofa screw driver'bitv56f. The member or key isadapted to be= received in the driven member or sleeve 31, the hub portion 52 matingwitha bored portion51 ofthemember 31 (Fig. 6), and theI toothA or lug' 531 passing through the aperture 43'in'thememberorfsleeve 31. It should be noted` that thefportionA 5120i the member 31' is-of a slightly reduced internal' diameter relative to the'portion 58 which receives the ratchets 38 and 33', and that the-tooth or lug 53 is substantially less in` width than`the-width ofthe aperture 43. In assembling tlie screw driver, this facilitates the insertionof' the member 5I'into the sleeve`31'.

The portions 4I and 49 ofthe sleeve 31? are centrally bored to receive the circular shanlr 5'9 of the bit 56' and the circular shank. 59 is grooved asat 66 to engage the key 48 andbe releasably held thereby against longitudinal movement'rel'ative to the sleeve or member 31.

A second sleeve 6I is adapted to slid'ably't over and rotate on the memberv or sleeve 31'. This sleeve 6I is provided with a plurality of longitudinal slots 62, 83 and 64', the slots 62v andl 63 being each of a width equal to the width ofthe slot 42 in the sleeve 31, but beingoi-settciroumferentially relative to each other a' distance equal tosubstantially half the width of' the slot 42. The slot 6.4 registers with the aperture 43m the sleeve 31'but is substantially narrower "than said aperture, and is of a width slightly greater: than the thickness of the-tooth or lug 53 of the member 5I, which tooth isadapted to pass through the slot- Bl and at its outer end be flush with the surface ofthe sleeve 6I. The memberl is provided with a plurality of circumferential slots or grooves 65 and 65 intersecting the slots 62' and 63 respectively at their midpoints. Inwardly from one edge there are out, in the member 6I, di- ,ametrically opposed cam groovesA 61 andA 68. Each of these cam grooves comprises a plurality of opposed surfaces 69 extending longitudinally of the sleeve 6I, a curved surface 1D` centrally-of the groove and oppositely inclined surfaces 1I and 1I' connecting the surfaces 69`to the curved surface 10.

Pins 12 and 13, which together "are of a length slightly less than the combinedf length of the slots 62 and 63, are adapted to set in `grooves-be'- tween the teeth of the ratohets 36' and 33'1 and td co-operate with the sides of thef slot 42?, in a manner later to be described, to'rotate'tlie bit 56. The pins 12 and 13 are retained "in ratchets 30 and 33 by spring straps 14. and15which seat in the grooves 65 and 66 of the sleevef'l, and these spring straps 14 and 15 are provided with enlarged heads 16 and 11, which extend into the slots 62 and 63 in positions overlying the pins 12 and 13, as best shown in Fig. 2;

A ring 1B slidably ts over the reduced-portion IBI of the sleeve 31 and carries integralcam fingers or lugs 19 and 80, which are sli'dably received in the slots or key ways 44 and 45 and the cam grooves 61 and 68. The cam fingers-'19 and 80 are each provided with oppositely tapering or beveled surfaces 8l and 82 for engaging the surfaces and 1I of the cam grooves Bland 68. For normally retaining the ring 'I8 landthe sleeve 6I in the position shown in Fig. 3, wherein the surface 8I of each camv finger'is in engagement with the surface .'I I and the surface 82 isin engagement with the surface 16, there is provided a spiral spring 83. This spiral spring. bears at one end against member 18 and at its other end against aninternalshoulder 84 (Rigs.V 2 andi) of a capmember` 85. Cap member 851isfprovided with an upstanding circular flange 86 and a beveled nose 81. The nose 8.1 is provided internally with a cylindrical portion 88"normally overflying the key 48' and an outwardly tapering or conical: portion 89; for a` purpose later to be described:

The cap member 85 is adapted to be moved rearwardly against action ofthe spring 83. by a cylindrical member or sleeve Slwhich fits loosely over the sleeve 6I andis providedat one end with down-turned or; inwardly.A extending flange 91 engaging the front surface ofthe fiange 8650i the cap 85. The outward movementof the cap 85 is limitedby anut 6?..tted. on the portion 49 ofthe sleeve 31, and this nut is provided with a beveled portion 93 co-operating withthe beveled portion 81 of the cap 85;

The screw driver isv assembled in the` following mannerz.

The threaded sleeve 34 is slid over the tube 24 and the spiral member 6' is threaded into the tube'l24 :andzoverthe spiral member 26. By means of a; special toolpassinginto the tube 6 from the end.` Il); the nut 21 isthreaded on the threaded portion 28 of the tube 26, thuslocking the spiral members 6 and 26 together against excessive longitudinal movement. The stud I3 and collar I6 are-thenassembled on theend I8 of the tube 6^.andlsecured thereto by the pin I8 which passes through the transverse openings I4, I5 and I1. The,shield 3 havingbeenpressed into the handle I1 untilits upper end is adjacent theupper end of thethandle I, the stud I3, which is now attached' to the spiral' member 6 and parts as sembled` thereto, is inserted through the opening 4' of the shield 3 with the hexagonal nut I9 seated inthe hexagonal opening 4. 'I'he washer 2|- and nutr 2.2 are 4then fastened onthe threaded end 28 ofthef stud I3:and the cap screw 2threaded` into the'. upper endof the handle I. The sleeve 6I is now`n slid. onto the sleeve 31 with the slot 64 of the sleeve 6I in alignment with tlie'slot 42, of the;sleeve31`. The driving pin 5Iv is then insertedinto the bore of the sleeveY 31 through the end:36: and the pinl having reached the reduced borey51'of'the sleeve 31 is now` tilted by an instrument, or by the tiltingof the sleeves 31 and. 6I, until thetoothxor lug `53passes` outwardlythrough the slot 42'` and the pin 5I then moves down the slot 42 intoz its proper position wherein the lug 53.5 passes through the aperture 43 of the sleeve 31 andtheslot 6.4of the sleeve 6I, as best shown in` Figs. 6 and 8L- The sleeve 31 to which has been assembled the sleeve 6I and pin 5I, is now passed. over the ratchets 38 and 33 and threaded onto the sleeve 34Y by which it is secured to the tube 2li.4 The pins12 and 13 are now dropped through the slots 62 and 63 and the slot 42 into the grooves formed by the teeth ofthe ratchets 3Il` and 33, and the spring straps 14` and 15 are placed in the circumferential grooves 65 and 66 in the sleeve 6I with the enlargedheads 16 and 11`in the slots 62 and 63 and resiliently engaging the pins or pawls 12 and 13. The ring 18 is slid on the portion 4I of the sleeve 31'with its fingers 19 and80` in the grooves 44 and 45.- and engaging the surfaces of the cam grooves 61 and 68. The keyy 48"` isnext inserted into the key-way 41 and the spring 83 and cap 85 are placed in position on the portion 4I of the sleeve 31. The sleeve 90 is then slid over the sleeve 6I with its depending flange SI in engagement with the upstanding flange 86 of the cap 85 and the nut 92 is then threadedjon the reduced portion 48 of the sleeve 6| in the groove in said ratchet.

31 to retain the parts in assembledrelation on said sleeve.

In order to insert the bit 56 into the screw driver, the sleeve 9D is slid aXially to the right '(Fig. 6) to'move the cap 85 axially to the right against the action of the spring 83; Inserting the bit in the end of the sleeve 31 the key 48 will be moved into the recess formed by the outwardly tapering portion 89 in the nose 81 of the cap 85 to permit the squared end of the bit to be inserted into the complementary opening 54 in the driving pin 5|, the key'48 dropping into the groove 69 in the bit to secure the bit against longitudinal movement. Upon release o'f the sleeve 96 the key-48 is locked in position by the cap 85.

The operationof the screw driver is as follows:

Upon longitudinal movement of the handle l, the spiral member 6 will be movedtherewith and the external teeth 1 engaging tooth 23 of the tube 24 will cause the tube 24 to rotate in one direction, while the internal teeth 8l of the spiral 6 engaging the external teeth of the spiral 26 will cause this member 26 to be rotated in a direction opposite to the tube 24. The ratchet 36 being connected to the tube 24, and the ratchet 33 being connected to the member 26, these ratchets will be rotated in opposite directions. The sleeve 3l is rotatedby manual manipulation of the knurled flange 39 to place the camrlngers 19 and 86 of the ring 18 in the position shown in Fig. 3, wherein the surfaces 8| of the ngers 19 and 86 are in engagement with the surfaces 1| of the cam grooves 61 and 68. The pins or pawls 12 and 13 will assumethe position shown in Figs. 9 and l0, wherein the pin 12, associated with the forward driving ratchet 30, is held by the sleeve The pin or pawl 13, associated with the reverse driving ratchet 33, will be free to move outwardly to permit the ratchet tomove reversely relative to the sleeve 31, to which motion is imparted in a forward driving direction by the pin or pawl 12. As shown in Figs. 2, 9 and 10, with the cam ngers 19 and 80 in the forward driving position in the cam grooves 61 and 68, the slot 63 of the sleeve 6| will be in alignment with the slot 42 of the sleeve 31 to permit the pin or pawl 13 to move outwardly or ratchet relative to the ratchet 33, but the slot 62 of the sleeve 6| will uncover only half of the slot 42. Since the ratchet 38 rotates ina clockwise direction, as viewed in Fig. l0, the pin 12 will be carried under the sleeve 6| and locked against outward movement, as before described. Driving motion in a forward direction is transmitted from the ratchet 36 through the pin 12, the sleeve 31, the cam fingers 19 and 60, the sleeve 6| to the driving pin 5| and the screw driver bit 56.

Whenever the force required to rotate the bit exceeds a certain predetermined value, the screw driver will be locked against spiraling action in the driving direction in the following manner:

The bit 56 will be momentarily held stationary but the sleeve 31 will continue to rotate causing the cam fingers 19 and 86 to be moved longitudinally of the sleeve 31 by the cam surface 1| of the sleeve 6|, which sleeve is momentarily held stationary with the bit 56 by the driving pin 5|. The sleeve 31 will move relative-ly to the sleeve 6| the angular distance permitted by vthe aperture 43 of the sleeve 31, it being noted lthat in the normal spiraling position the lug 53 is disposed centrally of the aperture 43, as shown in Fig. 8, but in the locking position one edge of the aperture 43 engages the tooth or lug 53 of the driving pin 5I, as shown in Fig. 11. The

'sleeve 31, in moving relatively to the sleeve 6|,

causes both pins or pawls 12 and 13 to be locked against outward movement by the sleeve 6|. These positions of the pins are shown in Figs. 4, 12 and 13 wherein the slots 62 and 63 of the sleeve 6| are both out of alignment with the slot 42, the inner half of the slot 42 being substantially closed by thesleeve 6| and the outer half of the slot 42 being closed by the sleeve 6| to an extent sufficient to prevent outward movement of the pin 13. being locked against movement relative to the sleeve 31, the spiral members 6, 26 and 24 are locked against longitudinal movement, and further rotation of the driving bit 56 in the driving direction may only be accomplished by rotating the handle I, the rotational force being transmitted by rotation of the members 6, 24, 26 and the ratchets 30 and 33 as a unit. From the ratchets 39 and 33 the motion is transmitted by both pins 12 and 13 to the sleeve 31 and from the sleeve 31 directly through the driving pin 5| to the bit 56.

It will be evident that upon movement of the handle in the opposite direction, that is in the non-driving direction, the spring 83 and the cam 18 will cause'the sleeve 6| to rotate relative to the sleeve 31 from the position shown in Fig. 5 to the original position shown in Fig. 3. The rotation of the sleeve 31 in the non-drivingdirection will aline the slot 42 in said sleeve with the slots 62 and 63 of the sleeve-6| in such manner that both pawls will be free to move outwardly of the slots 62 and 63 to permit free ratcheting of the ratchets 3|! and 33.

For the reverse operation of the driver bit, that is, in a direction to remove a screw, the sleeve 31 will be rotated by operation of the 'knurled portion 39 while retaining the bit against movement to cause the cam fingers 19 and 8l] to engage the cam surfaces 1| of the cam grooves 61 and 6B. The slot 62 of the sleeve 6| will then be in alignment with the slot 42, but the slot 63 will be out of alignment with said slot 42. The pin 13 will then be moved by its ratchet 33 under they overhanging portion of the sleeve 6|, which will prevent outward movement of the pin 13, but the pin 12 will be free to "ratchet outwardly, relative to its ratchet 3D. Reverse rotation of the driver bit will therefore be imparted through the ratchet 33, the pin 13 and sleeve 31 to the ring 18, cam ngers 19 and 80 to the sleeve 6|, and the driving pin 5| to the driver bit 5B.

If, during the reverse rotation of the bit, the force required exceeds the predetermined value, the screw driver will be locked against spiraling action in the driving direction in the same manner as previously described but the ratchets 3U and 33 will have free movement upon operation of the handle in the non-driving direction.

It will be seen from the above description, that applicant has provided a screw driver having tortionally actuated means which automatically locks the handle to the driver bit whenever the force required exceeds any desired predetermined value. In thus automatically locking, it will be apparent that back-spiraling of the handle is prevented. By providing separate and independent spiral members 24 and 26 for forward and reverse rotation respectively, it is possible to pro- Both ratchets 30 and 33, now

number. of threadsor parallel spirals is. limited.

to -twoby reason ofthe fact that both the forward and reverse spirals are cut in the external surface of the same tube or shaft.y l

It will also be apparent that applicantsA construction, as hereinbefore described,` eliminates the..usual cross-overs between the forward and reverse spirals and therefore eliminates the excessive wearA between the follower.. and the spirals which was caused by those cross-overs.. Further, it'.will be evident thatby reason .ofthe increased 29: number of parallel spirals whichrnay be formedY onfthe spiral member, the forces will be distributed equally upon eachof the spirals, thereby increasing the` life of the spiral members.

It will be further observed that there are no 25' exposed spiral members and hence no exposed lubricated surfaces, or surfaces adapted to pinch the users lingers, as the handle is movedlongitudinally to place or remove a screwv or to adjust. the screw driver. 30;: the screwv driver is automatically locked against spiraling Iaction both forwardly and backwardly Whenever the force required to turn the screw exceeds a predeterminedvalue, the work of placing and removing screwsin rmass production is Scconsiderably speeded because it then becomesl 45. cing any of its attendant advantages, andthe.

` right is hereby reserved .to make all such changes as fairly fall'within the scope ofthe following claims'. y

` The invention ishereby claimed asfollows:

, l 1.'A spiral work toolcomprising atool receiving member, a tubular actuating member, said. tubular member having spirals internally andv externally thereof, separate spiral members engaging said internal and external spirals and ro- ,r tating in opposite directions uponlongitudinal' movement of said actuating member, and means for. selectively connecting said rotatable spiral members to said tool receiving member to cause said last mentioned member to be rotated selec- 60,: tively in a clockwise or a counterclockwise direction upon longitudinal movement of said tubular actuating member.

f2. A spiral screw-driver comprising a bit receiving, member, a tubular actuating member, 65;, said `tubular member having spiralsinternally and externally thereof, separate spiral members engaging said internal and external spirals and rotating in opposite directions upon'longitudinal movement of said actuating member, manually 7og-operable means for selectively connectingsaid rotatable spiral` members to said bit receiving member to cause said last mentionedrnember to be rotated selectively in either direction upon longitudinal movement of said tubular. actuating, 75.j member, Yand automatically operable means.- for,

In View of the fact that.

simultaneously, connecting both said spiral members. to-saidbit receiving member thereby automatically to lock said spiral members against relative movement whenever the force required exceeds a predetermined value.

3. .A spiral screwdriver comprising a tubular actuatingmember, saidmember having spirals internally and externally thereof, separate spiral members engaging said internal and external spirals to be `rotated in opposite directions upon longitudinal movement of'said actuating member,.a driving l, sleeve selectively connectable to said spiral members.. for selective rotation in either direction, means detachably connecting a driver bitto said drivingsleeve for rotation therewith, and .a secondsleeve mounted on said rst slecvef'or. controlling the selective connection of said spiral :members to. Vsaid driving sleeve.

4. A spiral screw driver comprising an actuating` member, a vpair of separate spiral members rotated by said yactuating member in opposite directions, a driving sleeve, means for selectively connectingeither one or both of said spiral membersI to `said driving sleeve, a second sleeve shiftably mounted on said rst sleeve for movement relative theretoto control said connecting means, abit receiving member connected to said second sleeve, and. overload release means connecting said drivingy sleeve toy said second sleeve for movingsaidsleeves relatively to cause said connecting means. to simultaneously connect both said spiral members to saiddriving sleeve and thereby lockvsaid sleeves and said members against relative rotation whenever the force Vrequired exceeds a predeterminedvalue.

5. A. spiral screw driver comprising a handle,

latubular vactuating member having internal and external spirals,Y a tubular. actuated member having an` internal spiral engaging the external spiral of ythe actuating. member, a second actuated member passing through said first tubular actuated .member and having an external spiral engaging the internal spiral of the actuatingV member, a: pair of ratchets having longitudinal grooves, one of said'ratchets being securedto eachof said actuated'members, a rotatable member `forfreceiving. a driver bit, a driving sleeve connected. to said bit receiving member and rotatably journalledon said tubular actuated member, said drivingsleeve enclosing said ratchets and having. a. longitudinal slot therein', a plurality of rollers in saidslot and engaging in the longitudinal grooves. of, said ratchets, and means for selectively. preventing the movement of said rollersoutwardly, ofsaid grooves, thereby selectively to connect said ratchets to said driving sleeve for selective rotation ofisaid bit receiving member in either direction upon longitudinal movementof said handle.

. ,6..A` spiral screw driver comprising a handle, a. plurality of spiral members rotatable in opposite directions, apair of ratchets having longitudinal grooves, one of said ratchets being secured to eachof .said spiral members, a driving sleeve: loosely` journalled on one of said spiral members and enclosing said ratchets, said sleeve having. alongitudinal slot in alignment with said ratchets, a plurality of rollers in said slot and seated in the grooves of said ratchets for connecting.J said ratchets to said driving sleeve, a secondsleeve loosely journalled'on said driving sleeve and .adapted to overlie said rollers to prevent movement .of said rollers outwardly relative' to said .ratchets .thereby to connect said ratchets to said driving sleeve, said second sleeve having a rotary actuating members, Y said actuating members to said handle for rotatplurality vof laterally offset longitudinal slots adapted to be selectively aligned with the longitudinal slot in the driving sleeve to permit outward movement of a selected roller relative to said ratchets, a driving pin having an aperture for receiving a driver bit connected to said second sleeve and having a lost motion connection to said driving sleeve, and a spring-pressed cam member slidably mounted on'said driving sleeve, said second sleeve Ahaving a cam groove engaging said cam member whereby said cam causes movement of saidy driving sleeve relative to said second sleeve whenever the force transmitted to the driving pin exceeds a predetermined value to connect the driving sleeve directly to the driving pin and simultaneously connect both said ratchets to said driving sleeve thereby automatically to lock said spiral vmembers and said driving sleeve against relative movement.

7. A work tool comprising a handle, a rotatav ble member for receiving a work bit, a pair of means connecting ing said actuating members in opposite directions upon reciprocation of said handle, manually operable means for selectively connecting one of said rotary actuating members to said bit receiving member and simultaneously disconnecting V the other of said rotary actuating members from said bit receiving member, and meansI for automatically connecting both of said rotary actuating members to said bit receiving member4 whenever theforce required exceeds a predeterminedy Y value' to cause said bit receiving `member to rotate with said handle.

8, A spiral screw driver comprising a handle, a rotatable member adapted to receive adriver bit, a plurality of separate spiral members selectively connectible to the bit receiving'member for selectively rotating said bit receiving member in either direction, a common spiral member secured to said handle and operativelyv -connected to both of said'separate spiral vmembers for rotating saidv separate spiral members relatively in oppositedirections upon longitudinal movement `oi" the handle, and torsion res ponsive means for automatically locking said separate spiral members against relative movement to cause said bit, said spiral members and l v'" said handle to rotate asa unit wheneverthetorsion required of the screw driver receives a predetermined value.

9. A spiral screw driver comprising a handley 1 a rotatable member adapted to receive a driver relative movement of said spiral members whereby selectively to connect one of said spiral membersto said driver bit, and means for automatf ically operating said ratchet means whenever the force required exceeds a predetermined value to lock said spiral members" against relativev movement.

10. A spiral screw driver comprlsing a handle, a tubular actuating` member secured to said handle and having internal and external spirals, a

tubular actuated member having an internal spiral engaging the external spiral of the actuating member, a second actuated member passing through said first tubular actuated member and having an external spiral engaging the internal spiral of the actuating member, a pair of ratchets, one 'of -said ratchets being connected to each of said actuated members, a chuck for receiving" a driver bit, a driving sleeve connected to said chuck, said driving sleeve enclosing said ratchets, a plurality of ratchet pawls movable relative to Vsaid sleeve for connecting and disconnecting said ratchets `to and from said sleeve, and means selectively operable to prevent the movement of said pawls relative to said sleeve, thereby selectively to connect said ratchets to said driving sleeve for rotation of said bit receiving member in either direction uponl longitudinal movement of said handle 11; A spiral screw driver comprising a handle, a tubular actuating member secured to said handle and having internal and external spirals, a

tubular actuated member having an internal spiral engaging the external spiral of the actuating member, a second actuated member passing through said'rst tubular actuated memberfand three positions, in one of which one pawl is locked' against movement relative to the driving sleeve, in a second of which the other pawl is locked against movement relative to the driving sleeve and in the third of which both of said pawls are locked against movement relative to said driving sleeve, manually operable means for moving said second sleeve relative to said driving sleeveinto the rst and second of said positions, andautomatically operable means for moving saidsecond sleeve relative to the driving sleeve to the third of said positions whenever the forcerequired of the tool exceeds a predetermined value. 1 2. A spiral screw driver comprising a handle,

a tubular actuating member having internal andy external spirals, a tubular actuated member hav-A ingan internal spiral engaging the external lspiral of the actuating member, a second actuated membervpassing throughy said first tubular actuated member and having an external spiral engaging the internal spiral of the actuating member, a pair or" ratchets, one of saidY ratchets being secured to each of said actuated members, a driving sleeve enclosing said ratchets .and havinga longitudinal slot therein, a pair of ratchet pawls in said slot and engageable With said ratch-` ets, means selectively adjustable Vto one of two positions to prevent the movement of a selected oneof said two pawls outwardly of said-,slot

' thereby selectively `to connect said ratchets to said driving sleeve for rotation in either direction, and selectively adjustable to a third position to prevent movement of both of said pawls ed yon one end of said driving sleeve, said driving Vsleeve having a slotted keyway, a key in said keyway, a spring member normally retaining said cap member in locking engagement with said key and manually operable means carried by said driving sleeve and movable relative thereto for `moving'the cap member -relative to the driving 75* sleeve against the action of said spring to release said key and permit insertion and removal of the driver bit into and from the driving sleeve and a cam controlled by said spring member for automatically shifting said selectively adjustable means into its third position of adjustment Whenever the force applied by the screw driver exceeds a predetermined value.

13. A spiral screw driver comprising a handle, a rotatable member adapted to receive a driving bit, a plurality of separate spiral members selectively connected to said rotatable member for selectively rotating said member in either direction, and a common spiral member secured to said handle for operating both said first mentioned spiral members. v

14. A spiral screw driver comprising a handle',`

a rotatable member adapted to receive a driver bit, a plurality of separate spiral members connected to said handle for simultaneous rotation in opposite directions upon reciprocation of the handle, ratchet and paWl means for selectively e member for rotating said tool receiving member in either direction, a common spiral member connecting the driving member to both said iirst mentioned spiral members, means for locking the oppositely rotatable spiral members against relative movement to cause the bit receiving member and the spiral members to rotate as a unit, and torsionally actuated means for operating said locking means automatically whenever the torque applied by the tool exceeds a predetermined value.

16. A spiral work tool comprising a driving member, a rotatable tool receiving member, a pair of separate spiral members for selectively rotating said rotatable tool receiving member in either direction, and a common actuating meansY connecting said driving member` toboth of said spiral members for causing simultaneous rotation of said spiral members in opposite directions upon reoiprocation of the driving member.

17. A spiral screw driver comprising a handle, a rotatable member adapted to receive a driver bit, a pair of spiral members, common actuating means connecting the handle to both spiral members for rotating the spiral members in op posite directions upon longitudinal movement of the handle, means for selectively connecting one of said spiral members to said bit receiving member selectively to rotate said bit receiving member in either direction, means for locking said spiral member against relative movement to cause the bit receiving member to rotate only upon rotation of the handle and means responsive to the force exerted by the bit receiving member for automatically actuating said locking means whenever said force exceeds a predetermined value.

18. A spiral work tool comprising a driving member, a rotatable tool receivingmember, a pair of separate spiral members, common actuating means connected to said handle and to both of said separate spiral members for causing simultaneous 'rotation of said spiral members relatively in opposite directions upon reciprocation of the driving member, means selectively adjustable to one of two positions for selectively connecting one of said spiral members to said tool receiving member and selectively adjustable to a third position for locking said spiral members against relative rotation to cause said tool receiving member to rotate only upon rotation of thel driving member, and torsion responsive means for automatically actuating said selectively adjustable means to said third position whenever the torque applied by the tool exceeds a predetermined value.

GEORGE L. ROCK.

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