US2519811A - Screw holding screw driver - Google Patents

Description

Aug. 22, 1950 R. H. ALEXANDER SCREW HOLDING SCREW DRIVER Filed Jan. 13, 1948 l l l l l l Y y l NN. rrllllll QN MN .wN wNmN N INM .HNN NNN /sss 2 IVENToR. Y H. mim/msn MFM/6mm #Mmm Patented Aug. 22, `1950 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to Screwdrivers and more particularly to a screwdriver adapted to grip a screw so that it may be started and to thereafter release the screw so that it may be driven in the normal maner.

A main object of the invention is to provide a novel and improved screwdriver of the screwgripping type which is adapted to rmly grip the screw while it is being started, thereby eliminating the need for drilling a hole to receive the screw prior to driving it.

A further object of the invention is to provide an improved screwdriver of the screw-gripping type wherein the screw-gripping force is increased responsive to pressure applied to the screwdriver handle during the screw starting process, said screwdriver being relatively simple in construction, easy to manipulate and inexpensive to manufacture.

Further objects and advantages ofthe invention will become apparent from the following descripton and claims, and from the accompanying drawings, wherein:

Figure 1 is a longitudinal cross-sectional view taken through a screwdriver constructed in accordance with the present invention, the screwgripping means thereof being shown in spread position immediately prior to engagement with a screw.

Figure 2 is a longitudinal cross-sectional view similar to Figure 1 but showing the screwdriver in screw-gripping position.

Figure 3 is a fragmentary cross-sectional detail view of the forward portion of the screwdriver of Figure 1, showing the screw-gripping means retracted to inoperative position whereby the screw driver may be employed in the normal manner to complete the driving of the screw.

Figure 4 is a transverse cross-sectional detail view taken on line 4-4 of Figure 1.

Figure 5 is a fragmentary elevational view of the forward portion of the screwdriver of Figure 1, with the screw-gripping means shown in normal position prior to being placed in the spread position of Figure l.

Referring to the drawings, II designates the shank of the screwdriver, said shank being formed at its forward end with a reduced bit I2 having a blade portion I3 adapted to interlock with the driving groove of a conventional screw, such as shown at I4. Secured transversely in bit I2 is a bolt member I5 formed with laterally projecting headed ends I6, I6. Surrounding the intermediate portion of shank II and longitudinally slidable thereon is a sleeve member |165 Pivotally connected to the forward end portion of sleeve member I1 on a common transverse axis are channel-shaped jaw members I8, I8 embracing the forward end of shank II and formed with forwardly flaring cam surfaces I9, I9 at their forward end portions and with inwardly tapering concave gripping seat elements 20, 2i] at their forward ends. The cam elements I9, I9 are longitudinally slotted at 2|, 2| to receive the transverse bolt member I5, the heads I6, I6 of said bolt member bearing externally on said cam elements.

Rigidly secured to the rear portion of the sleeve member I'I is an annular flange 22. Designated at 23, is a hollow handle member housing the rear end portions of shank II and sleeve member I'I and formed with a forward sleeve portion 24 provided with an inturned annular end flange 25 slidable on sleeve member Encirling the sleeve member I1 and bearing between iiange 25 and flange 22 is a coiled spring 26 which biases the sleeve member I1 rearwardly with respect to handle ilange 25.

The rear end portion of shank II is formed with a slot 2'I and rotatably secured to the shank in said slot is a gear 28, the hollow handle member 23 being formed with upper and lower keyways 29, 29 in the same longitudinal plane in which said gear is located. Secured rigidly in the keyway 29 at one side of the shank II is a first rack bar 30 meshing with gear 28. Longitudinally slidable in the keyway 29 at the other side of shank II is a second rack bar 3|, also meshing with gear 28. The edge of rack bar 3| is notched at 32. Pivotally secured in a recess 33 formed in the wall of the handle member 23 adjacent rack bar 3| is a detent lever 34 biased clockwise, as viewed in Figure 1, by a spring bearing between the detent lever and the recess wall. One end of detent lever 34 is adapted at times to interlock with the notch 32 in rack bar 3| by the biasing action of spring 35. The other end of said lever carries a release button 35 which projects externally of the handle member 23 for rotating said lever manually to disengage it from the notch 32.

In the normal position of the screwdriver, spring 26 acts to maintain liange 22 in abutment with the forward end of rack bar 3|. The rack bar 3| is so dimensioned that under these conditions the bolt member I5 is about midway in the cam slots 2|, 2| and the heads I6, I6 of said bolt member engage the intermediate portions of the cam elements I9, I9 and thereby hold the jaw elements I8, I8 in their partly closed positions, shown in Figure 5. To engage the head of a screw, the sleeve member I1 is held and the handle member 23 is pulled rearwardly. Force is thereby transmitted to shank Il to retract said shank with respect to sleeve member I1 to the position shown in Figure 1, whereby the heads I6, I6 of bolt member I5 travel to the rear ends of the slots 2I, 2|. In this position lever 34 is engaged in notch 32. This allows the jaw members I8, I8 to be separated sufliciently to receive the head of a screw I4 within the concave seat elements 20, 20 with the blade tip I3 engaged in the kerf of the screw. Lever 34 is then released by pushing button 36 and handle 23 is then moved forwardly with respect to sleeve member Il, causing shank II to be moved forwardly and moving the bolt heads I6, I6 forwardly on the flaring cam surfaces I9, I9 to return the jaw members I8, I8 to positions such as shown in Figure 2, wherein the head of screw I4 is clamped by the concave seat elements 20, 20. The screw may then be started and driven into its int-ended location.

vAs forward pressure is applied to handle 23 during the screw starting process, gear v2S `is ro.- tated counter-clockwise, as viewed in Figure 2, by the forward movement of rack bar 3d. rlhis causes rack bar `3| to be moved rearwardly. As rack bar 3I moves rearwardly out of abutment with flange .22, the expansive force of spring 25 is applied entirely to said dange and -acts on sleeve member I'I to urge said sleeve member rearwardly with respect to shank II. 1This wedges bolt heads I6, I 6 more firmly .against the forwardly daring .cam .surfaces I9, I9 and tightens the grip of the jaw members 1B, I8 on the screw head.

After the screw has been startediand it is -no vlanger necessary to clamp iit to the screwdriver bit, the screw may be released by Iholding the 'sleeve member Il and pulling rearwardly on the handle member 23. vThis rotates gear 28 clockwise, as viewed in Figure 2, and moves Arack barJ3I forwardly into abutment with-flange 22, thereby exerting a rearwardvpull on shank -II with respect to the sleeve member Il. When shank Ii moves rearwardly with respect to said sleeve member, the bolt heads I I `travel rearwardly on the cam surfaces I9, kI9 andrelease the jaws I8, I8 allowing the screw head tobe disengaged from between the concavevgripping elements '28, 20. After the screw head has-been thus disengaged, handle member 23 is pushed forwardly with `respect to sleeve member -I`I, causing the rack bar SI to be retracted untilthe detent lever 34 enters the notch 32l in l.said rack bar. v'lChis operation also causes the spring 25, acting through ange 25, handleZS, rack bar Sil, and gear 28 tomove .the shank 'II forwardly with respect to sleeve member'll' until the gripping elements 2D, 2Q are inthe inoperative positions thereof, shown -iniFigure 3, Aengaging the opposite surfaces of the blade LI3 of the screwdriver bit. Since the detent lever 34-when seated in notch 32, opposes any furtherfor-ward movement of handle member23 with respect to rack bar 3|, forward pressurefon the handle member will be transmitted .directlyY to .shankf II through the rack bars 30 and 3.! and .gear 28, whereby the screwdriver may be employed-in .the driving ofthe screw. After .theioperation is completed, the push button 3S is pressed inwardly, releasing the rack bar SI a-nd lallowing the parts'to Vbe returned to their normal-positions illustrated )in `Figure 5.

While a specific embodiment of a screwdriver of the screw-gripping type has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

l. In a screwdriver, a shank member having a bit portion adapted to engage the kerf of a Screw, a sleeve member slidable on said shank member, a plurality of jaw elements secured to said sleeve member, inter-engaging means on said shank member and jaw elements formed and arranged to contract said jaw elements responsive to rearward axial movement of said sleeve member with respect to said shank member, a handle member slidable on said sleeve member, inter-engaging means carried by said handle vmember and shank member, a portion of said latter inter-engaging means being longitudinally mcvable with respect to said handle melilber responsive to sliding movement of the handle member on said sleeve member and being formed and arranged to act between the sleeve member and the shank member to produce relative axial movement of the shank member with respect to the sleeve member in one direction, and spring means biasing the sleeve member for movement relative to the shank member in .the `opposite direction.

2. In a screwdriver, a shank member having a bit portion adapted to engage the kerf of a screw, a sleeve member slidable on said shank member, a plurality of jaw elements pivotally secured to said sleeve member, inter-engaging cam means .on said shank member and .jawelements formed and arrangedto contract said jaw elements responsive to rearward `axial `movementof said sleeve member with respect to said shank member, a handle member slidable on said sleeve member, a bar element slidably carried Vvin said handle member and :bearing on said sleeve `member to oppose rearward ymovement thereof, `respective spaced .abutment ,elements on said handle member and sleeve member Vlocated forwardly of said bar element, a spring disposed between said abutment elements and being formed and arranged tobias the sleeve member rearwardly ,in opposition to said bar element, and inter-.engaging meanscarried by said shank member and handle member and being formed and arranged to move said bar mem-ber out of engagement with said sleeve member responsive to forward movement v,of the handle member .on said sleeve member.

3. VIn Aa screwdriver, a shank member having abit-portion adaptedto engage thekerf .of a screw, a sleevemember slidable Aon said shank member, ka plurality of jaw .elements pivotally secured to said sleeve member, inter-.engaging cam means Yon saidshank member and jaw elements formed and arranged to contractsaid jaw elements around the kerf-engaging portion ,of .the shank member responsive to rearward 4axial movement of said sleeve member with respect to said shank member, a handlememberslidable onsaidsleevemember, a gear carried by said shank member, a first rack bar rigidlycarried 'by said handle member .and meshing with said gear, a, second rack barslidableV in. said handlemember and also meshing withv said gear, said-rack bars meshing with the gear at diametrically oppositapointsron 4the gear, said second .bar

normally bearing on said sleeve member to oppose rearward movement thereof with respectI to said shank member, and a spring bearing between the handle member and sleeve member in opposition to said second rack bar, said spring being formed and arranged with respect to the handle member and sleeve member to move the sleeve member rearwardly with respect to the shank member when said second bar is moved rearwardly with respect to said handle member.

4. In a screwdriver, a shank member having a bit portion adapted to engage the kerk of a screw, a sleeve member slidable on said shank member, a pair of opposed screw-head-engaging jaw elements pivotally secured to said sleeve member, inter-engaging cam means on said shank member and jaw elements formed and arranged to contract said jaw elements around the kerf-engaging portion of the shank member responsive to rearward axial movement of said sleeve member with respect to said shank member, a handle member slidable on said sleeve member, a gear rotatively carried by said shank member, a first rack bar iixed to said handle member meshing with said gear, a second opposing rack bar slidable in said handle member also meshing with said gear, said rack bars meshing with the gear at diametrically opposite points on the gear, said second rack bar normally bearing on said sleeve. member to oppose rearward movement thereof with respect to said shank member, a spring bearing between the handle member and sleeve member in opposition to said second rack bar, said spring being formed and arranged with respect to the handle member and sleeve member to move the sleeve member rearwardly with respect to the shank member when said second bar is moved rearwardly with respect to said handle member, and means for at times locking said second bar in rearwardly moved position in said handle member.

ROY H. ALEXANDER.

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

UNITED STATES PATENTS Number Name Date 332,438 Richardson Dec. 15, 1885 1,399,635 Lundmark Dec. 6, 1921 FOREIGN PATENTS Number Country Date 29,395 Great Britain Dec. 17, 1910

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