GB1578372A - Tools - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO TOOLS (71) We, LAP SHING TRADING COM PANY LIMITED, a British Company, of Marina House, 707-710 Queen's Road Central, Hong Kong, and HUNG SANG MANUFACTORY, a Chinese Body Corporate, of Kin Hing Industrial Building, 14th Floor Flat B, 17-23 Shek King Street, Kwai Chung, New Territories, Hong Kong, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to hand tools for example screw-drivers.

Many hand tools are today provided with removable work-bits. For example, a screwdriver may have a number of bits, a chosen one of which is fitted to the screw-driver to carry out a required operation. It must be easy to fit a selected bit to the screw-driver and once fitted the bit must be held firmly in place. It must also be easy to remove the bit when necessary.

Accordingly, it is an object of the present invention to provide a tool adapted to receive a removable bit and in which fitting and removal of the bit can readily be effected.

According to the present invention, there is provided a tool comprising a handle, a shaft secured to the handle, a bit-receiving socket on the shaft, a magnet housed in the socket and positioned and adapted to hold a tool bit in the socket, and in which the handle has an internal, openable chamber for receiving tool bits when not in use.

In the event that the tool shaft is intended to impart a rotary motion to the tool bit, the socket is adapted to transmit such motion from the shaft to the tool bit.

The socket may be of a non-magnetic material. The magnet may be located at the inner end of the socket and a pole face of the magnet may form the inner end wall of the socket.

The shaft may be of non-magnetic material with an end portion adapted to receive a bit and to transmit thereto rotation of the shaft about its longitudinal axis, the end portion accommodating a permanent magnet.

Preferably, the chamber in the handle may be closable by a removable cap.

By way of example only, a screw-driver embodying the invention will now be described with reference to the accompanying drawing which is a vertical section of the screw-driver.

Referring to the drawing, the screw-driver shown has a non-magnetic shaft 1 having attached at one end a handle 2 composed of a plastics material. The other end of the shaft has a tubular portion or socket 3 which is internally substantially non-circular in crosssection, for example hexagonal. Into this hollow end fits a hexagonally sectioned part 4 of a screw-driver bit 5. The part 4 has an end surface 9. The bit 5 is of magnetic material and is held in place by a magnetic force of attraction-acting between the surface 9 and a permanent magnet member 6 housed internally at the end of the hollow portion 3.

The magnet 6 is so arranged that one of its pole faces forms the inner end wall of the hollow portion 3.

The handle 2 is moulded on to the shaft 1 and firmly anchored by a keying structure 7 forged into the shaft. The keying structure 7 ensures that an axial rotation of the handle is imparted to the shaft. Moulded in the handle is a chamber 8 which is closable by a screw cap 10, also made of a plastics material. The chamber 8 is used to store a spare bit or bits and the bit 5 when the screw-driver is not in use. One such spare bit is shown at 11.

When the screw-driver is to be used a bit suitable for the type of screw to be operated is selected from those stored in the chamber 8.

It is placed in the tubular portion 3 and is retained by magnetic attraction acting on the holding surface 9. When the screw-driver bit is placed in the slot of a screw of magnetic material, the screw, the bit 4 and the permanent magnet 6 form a series magnetic circuit. Thus force of attraction exists not only between the bit and the magnet but also between the bit and the screw. The surface 9 is arranged to have a sufficient surface area and shape so that the force of attraction between it and the magnet exceeds that between the bit and the screw. This ensures that when the screw-driver is pulled away from the screw the bit is retained in the tubular portion 3.The existence of a force of attraction between the screw and screw-driver is useful as it enables the screw to be held by the screw-driver thus enabling screws to be carried to and affixed in places which are otherwise inaccessible.

Whereas the description above is concerned with a simple hand-operated screw-driver, the invention is also applicable to many other tools, for example a socket spanner or a bradawl can be formed by replacing the bit 4 with a bit having a socket spanner or a bradawl tip. Furthermore, the tubular portion can be used to drive suitably sized and shaped nuts and bolts. The tubular section and bit are hexagonal because the hexagonal bit is readily available, however any shape which prevents rotation will suffice; for example circular cross-section with a key and key way or pentagonal cross-section.

In the embodiment the handle 2 is rigidly mounted on the shaft 1, rotation may, however, be imparted to the shaft by a motor, thus causing the shaft to rotate while the handle remains stationary in the hand of the operator. This is particularly useful when a large number of screws require to be tightened in as short a time as possible such as on a factory production line. The motor in such circumstances is usually pneumatic.

WHAT WE CLAIM IS: 1. A tool comprising a handle, a shaft secured to the handle, a bit-receiving socket on the shaft, a magnet housed in the socket and positioned and adapted to hold a tool bit in the socket, and in which the handle has an internal, openable chamber for receiving tool bits when not in use.

2. A tool as claimed in claim 1 in which the magnet is a permanent magnet 3. A tool as claimed in claim 1 or 2 in which the socket is of a non-magnetic material.

4. A tool as claimed in any one of claims 1-3 in which the magnet is located at the inner end of the socket.

5. A tool as claimed in claim 4 in which a pole face of the magnet forms the inner end wall of the socket.

6. A tool as claimed in any one of the preceding claims in which the socket is of non-circular cross-section in a plane transverse to its length.

7. A tool as claimed in any one of claims 1-6 in which the socket has at least one key or key slot for transmitting rotary motion to a tool bit.

8. A tool as claimed in any one of claims 1-7 and including a motor capable of rotating the shaft with respect to the handle.

9. A tool as claimed in any one of claims 1-8 wherein the handle is moulded from a plastics material.

10. A tool substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. material, the screw, the bit 4 and the permanent magnet 6 form a series magnetic circuit. Thus force of attraction exists not only between the bit and the magnet but also between the bit and the screw. The surface 9 is arranged to have a sufficient surface area and shape so that the force of attraction between it and the magnet exceeds that between the bit and the screw. This ensures that when the screw-driver is pulled away from the screw the bit is retained in the tubular portion 3. The existence of a force of attraction between the screw and screw-driver is useful as it enables the screw to be held by the screw-driver thus enabling screws to be carried to and affixed in places which are otherwise inaccessible. Whereas the description above is concerned with a simple hand-operated screw-driver, the invention is also applicable to many other tools, for example a socket spanner or a bradawl can be formed by replacing the bit 4 with a bit having a socket spanner or a bradawl tip. Furthermore, the tubular portion can be used to drive suitably sized and shaped nuts and bolts. The tubular section and bit are hexagonal because the hexagonal bit is readily available, however any shape which prevents rotation will suffice; for example circular cross-section with a key and key way or pentagonal cross-section. In the embodiment the handle 2 is rigidly mounted on the shaft 1, rotation may, however, be imparted to the shaft by a motor, thus causing the shaft to rotate while the handle remains stationary in the hand of the operator. This is particularly useful when a large number of screws require to be tightened in as short a time as possible such as on a factory production line. The motor in such circumstances is usually pneumatic. WHAT WE CLAIM IS:

1. A tool comprising a handle, a shaft secured to the handle, a bit-receiving socket on the shaft, a magnet housed in the socket and positioned and adapted to hold a tool bit in the socket, and in which the handle has an internal, openable chamber for receiving tool bits when not in use.

2. A tool as claimed in claim 1 in which the magnet is a permanent magnet

3. A tool as claimed in claim 1 or 2 in which the socket is of a non-magnetic material.

4. A tool as claimed in any one of claims 1-3 in which the magnet is located at the inner end of the socket.

5. A tool as claimed in claim 4 in which a pole face of the magnet forms the inner end wall of the socket.

6. A tool as claimed in any one of the preceding claims in which the socket is of non-circular cross-section in a plane transverse to its length.

7. A tool as claimed in any one of claims 1-6 in which the socket has at least one key or key slot for transmitting rotary motion to a tool bit.

8. A tool as claimed in any one of claims 1-7 and including a motor capable of rotating the shaft with respect to the handle.

9. A tool as claimed in any one of claims 1-8 wherein the handle is moulded from a plastics material.

10. A tool substantially as hereinbefore described with reference to the accompanying drawing.