US3703916A

US3703916A - Screwdriver with an exchangeable tip

Info

Publication number: US3703916A
Application number: US144976A
Authority: US
Inventors: Owe Wilhelm Sundsten; Karl Bertil Sune Johansson
Original assignee: SKANDINAVISK FOTO TRADE AB
Current assignee: SKANDINAVISK FOTO TRADE AB
Priority date: 1971-05-19
Filing date: 1971-05-19
Publication date: 1972-11-28
Anticipated expiration: 1989-11-28

Abstract

In a screwdriver with a handle supporting a coaxial rod and a sleeve surrounding the rod, the forward free end of the rod is tapered to engage, when desired, the inside of the tapered forward end of the sleeve. In the forward end of the rod is a slit for receiving the flat rear end of an exchangeable screwdriver tip. When moving the sleeve axially relatively the rod in one direction by means of a control member, the legs of the rod defining the sides of the slit will engage the inside of the tapering sleeve end and press the legs against the tip to secure it to the screwdriver, whereas movement in the opposite direction will release the tip.

Description

United States Patent Sundsten et al.

[ SCREWDRIVER WITH AN EXCHANGEABLE TIP [72] Inventors: Owe Wilhelm Sundsten, Johanneshov; Karl Bertil Sune Joharmon, I-luddinge, both of Sweden [73] Assignee: Skandinavisk Foto Trade A B,

Nacka, Sweden [22] Filed: May 19, 1971 [21] App]. No.: 144,976

52 U.S.Cl ..14s/50R,279/43 [51] Int. Cl ..B25b 15/02, B23b 31/12 [58] Field of Search 145/50 R, 50 A, 50 B, 50 C, 145/50 F, 66; 279/42, 43, 45, 50

[56] References Cited UNITED STATES PATENTS 7 3,121,572 11/1961 Torok ..145/5OR [451 Nov. 28, 1972' FOREIGhI PATENTS QR APPLICATIONS 236,236 12/1925 Primary Examiner-Robert C. Riordon Assistant Examiner-Mark S. Bicks Attomey -Sa.lter & Michaelson ABSTRACT side of the tapering sleeve end and press the legs against the tip to secure it to the screwdriver, whereas movement in the opposite direction will release the tip.

3 Clains, 8 Drawing Figures England ..145/so B Q PATENTi-iflm 28 m2 llillf i INVENTORS OWE WILHELM SUNDSTEN K65} BERTIL SUNE JOHANSSON ATTORNEYS 1 SCREWDRIVER WITH AN EXCHANGEABLE TIP The present invention relates to a screwdriver with an exchangeable tip. In comparison with known types of screwdrivers of this kind, the screwdriver according to the present invention has the advantage of i.a. possessing essentially the same form as a common screwdriver without having any uncovered tip securing tongs or the like which weaken the screwdriver and easily become inoperable due to the penetration of dirt. The present invention also has the advantage of being simple and inexpensive to produce and of enabling a robust design which is resistable to rough handling.

A preferred embodiment of screwdriver according to the invention is shown by way of example in the accompanying drawing.

FIG. 1 is a partially broken side-view of a screwdriver according to the invention having a rod located in a sleeve and provided with an exchangeable tip,

FIG. 2 is a plan view of a portion of the rod having a wedge shaped forward end,

FIG. 3 shows the forward end portion of the rod seen from the side with an axial slit,

FIG. 4 is a separate view of the tip,

FIG. 5 is a partially broken view seen from above of the forward end portion of the screwdriver in FIG. 1,

FIG. 6 is a cross-section along line 6-6 in FIG. 5,

FIG. 7 shows on an enlarged scale the tip of FIG. .1, and

FIG. 8 shows another type of tip to be secured according to the invention.

The screwdriver shown in FIG. 1 comprises an elongated handle 1 and a rod 2 fixed in relation to said handle and extending coaxially therewith. The rod has a turned down rearward portion 3 which extends into a corresponding bore in the handle 1 and can be fixed in same by providing the rearward end of said rod with a slot (not shown) which conforms with an expanding element (not shown). The rod 2 can also be fixed in the handle in another way, e.g., by casting.

The forward end of the rod 2 is milled down to a wedge shape with two sides 4, 5. In this part of the rod,

the rod has an essentially rectangular cross section. The

end of the rod is provided with an axial slit 6 to provide two legs 7, 8 of a tong for securing an exchangeable tip 9 which is provided with a rectangular fastening surface to be located between the legs 7, 8. On the outside of the rod 2 is a tubular sleeve 10, the forward end of which is conically flattened at 11 to form a seat for the sides 4, 5 of the forward end of the rod 2. At its rearward end, the sleeve has an external thread 13 which cooperates with a corresponding internal thread 13a in a control member 14 in the form of a nipple. This member 14 is joumalled about that part of the turned down portion 3 of the rod 2 which lies between the end of the handle 1 and a shoulder 2a of said rod. It is seen that the control member 14 is hereby axially fixed and displaces the sleeve 10 when rotated in either direction, depending on the direction of the rotation. The control member 14 is preferably provided with a handle portion 15 to be gripped by the fingers of the I person using the screwdriver.

When an exchange of tips is desired, the control member 14 need only be rotated in one direction so that the sleeve l0 will be displaced to the left and the legs 7, 8 release their grip on the tip 9 which can then be easily removed. When a new tip is inserted, the control member 14 is rotated in the opposite direction so that the sleeve 10 is displaced to the right instead. Thus, the inner sides of the sleeve s 10 tapering forward end portion 11 press on the sides 4, 5 of the rod 2 to effect compression of the legs 7, 8 against the new tip. The tapering forward end portion 11 of the sleeve 10 thus serves as a seat forthe legs 7, 8 and concurrently prevents the sleeve 10 from rotating relative to the rod 2 Currently used screwdriver tips are generally made with an edge whose sides converge towards a point in front of the screwdriver. As a result of this conicity, the

tipv has a tendency to leave the slot of the screw head during vigorous tightening. In order to overcome this drawback, the screwdriver tips used together with the present screwdriver are preferably provided with edges whose side surfaces l6, l7 converge towards the handle of the screwdriver when the tips are in position for use. This will be seen from FIG. 7.

FIG. 8 illustrates another tip 9a having teeth or edges 18 for screws with heads provided with several radially extending, equally spaced grooves in the head of the screw in a manner known per se.

The handle 1 may have one or more tip receiving chambers opening at the rear end of the handle and closed by means of a detachable lid. Thus, anumber of equal or different tips may be stored in such chamber.

Within the scope of the invention, the sleeve 10 may befixed to the handle, and the rod 2 may be axially displaceable relative to the sleeve and extend axially through the handle to a control member (not shown) which is rotatably joumalled at the rear end of the handle and adapted to effect the axial displacement forwards and rearwards, respectively, by means of a threaded mechanism of principally the same type as disclosed in connection with the threads 13 and 13a in FIG. 1. I

What we claim is:

l. A screwdriver with an exchangeable tip, characterized in that the handle of the screwdriver supports a rod element coaxial with the handle, and a sleeve element enclosing the rod' element, that the forward end portion of the rod element is providedwith an axial slit for receiving the flat end of an exchangeable tip between two spaced legs forming the sides of the slit, that the legs taper towards the free end of the rod to form a wedge like member with two conically tapering outer side surfaces, that the forward end portion of the sleeve is formed to taper substantially in conformity with said legs to form a seat for them, that one of said elements is secured to the handle and the other element is axially displaceable but non-rotatable relative to the first element and the handle, and that a threaded control member is rotatably mounted but substantially axially stationary relative to one of said elements and has a thread cooperating with a thread on the other element to effect axial displacement of said element when the control member is rotated in one direction to effect relative axial displacement of the sleeve member and rod element with the result that the legs engage the inner opposite sides of the forward tapering end portion of the sleeve member and are pressed against the flat end portion of a tip to secure it to the screwdriver 2. A screwdriver according to claim 1, characterized in that the rearward end portion of the rod element has a shoulder and a portion with a reduced diameter, that said reduced portion of the rod element is partially situated and secured in the handle, and that a nipple is rotatably mounted on the reduced part of the rod lying outside the end of the handle, said nipple functioning as a rotatable control member and having an internal thread cooperating with an external thread on the sleeve, said nipple being held axially substantially stationary relative to said handle by, on one side, one end surface of the handle and, on the other side, by the in .that the tips intended for use together with the screwdriver have edges with opposite sides which converge in a direction towards the rear end of the tip which is flat to be received between the spaced legs of the forward end of the rod.

Claims

1. A screwdriver with an exchangeable tip, characterized in that the handle of the screwdriver supports a rod element coaxial with the handle, and a sleeve element enclosing the rod element, that the forward end portion of the rod element is provided with an axial slit for receiving the flat end of an exchangeable tip between two spaced legs forming the sides of the slit, that the legs taper towards the free end of the rod to form a wedge like member with two conically tapering outer side surfaces, that the forward end portion of the sleeve is formed to taper substantially in conformity with said legs to form a seat for them, that one of said elements is secured to the handle and the other element is axially displaceable but non-rotatable relative to the first element and the handle, and that a threaded control member is rotatably mounted but substantially axially stationary relative to one of said elements and has a thread cooperating with a thread on the other element to effect axial displacement of said element when the control member is rotated in one direction to effect relative axial displacement of the sleeve member and rod element with the result that the legs engage the inner opposite sides of the forward tapering end portion of the sleeve member and are pressed against the flat end portion of a tip to secure it to the screwdriver whereas rotation of the control member in opposite direction will release the tip.

2. A screwdriver according to claim 1, characterized in that the rearward end portion of the rod element has a shoulder and a portion with a Reduced diameter, that said reduced portion of the rod element is partially situated and secured in the handle, and that a nipple is rotatably mounted on the reduced part of the rod lying outside the end of the handle, said nipple functioning as a rotatable control member and having an internal thread cooperating with an external thread on the sleeve, said nipple being held axially substantially stationary relative to said handle by, on one side, one end surface of the handle and, on the other side, by the shoulder formed between the thicker part and narrower parts of the rod element so that when said nipple is rotated, it brings about an axial displacement of the sleeve element.

3. A screwdriver according to claim 1, characterized in that the tips intended for use together with the screwdriver have edges with opposite sides which converge in a direction towards the rear end of the tip which is flat to be received between the spaced legs of the forward end of the rod.