US 2560912 A
Description (OCR text may contain errors)
y 1951 G. AITTO 2,560,912
EXPANDING BIT SCREW DRIVER Filed June 28, 1947 INVENTOR. George Aizto ATTORNEY l atented July 17, 1951 UNITED- STATES PATENT OFFICE I I I I 2,560,912
EXPANDING BITSCREW DRIVER George Aitto, New York, N. Y.
Application June 28, 1947, Serial No. 757,882
ing the setting of the screw into the hole into which it is to be driven.
Another object of the invention is the provision of a screw driver having the shank thereof formed of two separate sections possessing a degree of resiliency, with the tips thereof complementarily triangular in cross-section and adapted to be moved longitudinally over each other to fit the width of the slot in the screw head, together with means for so moving the shank sections in either direction.
The above as well as additional objects will become apparent in the following description, wherein characters of reference refer to likenumbered parts in the accompanying drawing. It is to be noted that the drawing is intended for the purpose of illustration only, and that it is neither desired nor intended to limit the invention necessarily to any or all of the specific details of construction shown excepting insofar as they may be deemed essential to the invention.
Referring briefly to the drawing, Fig. l is a front elevational view of the screw driver illustrating the invention.
Fig. 2 is a top plan view of the same.
Fig. 3 is a side elevational view of the same.
Fig. 4 is a sectional View taken on the line 4-4 of Fig. 3.
Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4.
Fig. 6 is a front elevational view of the screw driver shank per se.
Fig. '7 is a sectional view taken on the line 1-1 of Fig. 4.
Fig. 8 is a fragmentary perspective view of the tip of the shank.
Fig. 9 is a perspective view showing, fragmentarily the tip of the shank applied to the head of a screw, the latter having parts broken away and being shown partly in section.
Referring in detail to the drawings, the numeral I indicates the barrel-shaped hollow handle of the screw driver, having the cap H rotatably mounted on one end thereof and provided with an internal threaded axial bore l2. The cap ll may be rotatably mounted as stated by any suitable means, such as, for example, by providing pins 13 in the handle projecting into a circumferential groove [4 in the cap.
The screw driver shank I is split by a slot 16 into two end members or sections I! which are 1 Claim- (Cl. 145-60) bent outwardly intermediate their length at l8, and whose extremities are shaped into two complementary triangular or wedge-shaped'tips, l9, and HM, the triangular or wedge-shaped here referred to relating to the cross-sectional areas of the tips and of course to their areas at their extremities. The lower extremity 20 of the shank I5 is threaded and registers in the bore I2.
The barrel in is provided with two diametrically opposed longitudinal grooves 2|, and the shank members H are provided with diametrically opposed ears 22 which register slidably in these grooves. The upper end of the bore through the barrel [0, tapers, that is, is conical, as shown at 23, so that when the shank is drawn into the barrel the upper ends of the members ll. will be urged toward each other as the angularly bent or deformed portions I8 of these members ride over the tapering surface '23, and conversely, as
the shank is advanced out of the barrel the members I! are urged to separate because of their inherent resiliency. As the members I! thus come together, it is apparent that their tips I9 and l9a will slide over each other and thus increase the thickness of the resultant combined tip of the shank, and conversely, as the members ll separate the thickness of the combined shank tip will diminish while the Width of the tip will increase. Thus, the thickness of the screw driver tip may be varied to accommodate the thickness of the screw slot to facilitate the driving of a screw and also to enable the screw to be carried on the screw driver tip to its point of application.
The shank I5 is either advanced from or withdrawn into the barrel by rotation of the cap II in one direction or the other. In using the screw driver to carry a screw to its point of application, the combined tip l9l9a is inserted into the screw slot and the cap H is rotated until the screw is firmly held. Then the screw is inserted into its hole and the screw driver is turned in the normal manner, by means of the handle [0, and any further rotation of the cap II will have no elfect other than to drive the screw home.
Obviously, modifications in form and structure will or may be made within the spirit or scope of the invention.
A screw driver comprising a hollow barrelshaped handle, one end of saidhandle having an annular recess therein coaxial with axis of the handle, a cap having a boss registering rotatably in said recess, said boss having a cir-.
cumferential groove therein, said handle having of said recess and registering in said groove, the other end of said handle being open, said open end having a mouth, a shank of greater length than the handle mounted in said handle, said cap having a threaded axial bore, said shank having one extremity threaded and registering in said cap bore, said shank having a split therethrough extending from the other extremity thereof to a point intermediate the length of the shank thereby dividing the shank into two sections, said shank being made of a resilient material and having said sections normally positioned in separated condition, said sections being deformed angularly and divergently at the neighborhood of said mouth whereby the deformed portions thereof are urged by said resiliency against said mouth, said sections having extensions thereon of equal length extending convergently toward each other at acute angles to said sections, the extremities of said extensions comprising mutually complementary wedge-shaped tips adapted to slide together and to be brought together to form a unitary substantially rectangular tip for the screw driver, said handle having diametrically opposed longitudinal internal grooves, said shank sections having ears registering in said grooves, rotation of said cap with respect to said handle in one direction causing said shank to be drawn into the barrel and thereby causing said shank sections and said extension tips to be brought together, rotation of said cap in the opposite direction permitting said resiliency to urge said shank sections and said extension tips to separate.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS