GB2034619A - Gear-drive hand tool - Google Patents

Abstract

A hand tool (2) comprising a handle (4), a body, rotatable first and second shafts (6, 8), and a gearing arrangement (10) giving a rotational speed advantage from the first shaft (6) to the second shaft (8) and a mechanical advantage from the second shaft (8) to the first shaft (6), the hand tool (2) being such that the handle (4) can be positioned on either of the first and second shafts (6, 8) to obtain either the rotational speed advantage or the mechanical advantage. The opposite can be or carry a wrench socket, screwdriver head, drill socket, sanding head or paint stirrer. <IMAGE>

Description

SPECIFICATION A hand tool with a gearing arrangement This invention relates to a hand tool with a gearing arrangement.

Many types of hand tools are known such for example as screwdrivers, spanners and drills. The screwdrivers and spanners are employed for tightening and untightening fastening devices such as screws and bolts and situations often arise wherein the screwdriver or the spanner does not allow sufficient torque to be transferred to the head of the fastening device for it to be undone. Situations also arise where it would be desirable to tighten the fastening device at a faster rate than is possible with the known screwdrivers and spanners.

One well known tool with a gearing arrangement is a hand drill but the mechanical advantage from such a hand drill is not great and the hand drill is only designed for the purpose of producing reasonable speeds of rotation of a drill bit for drilling holes in a object.

It is an aim of the present invention to provide a hand tool which can be used one way for obtaining a rotational speed advantage and which can be used another way for achieving a mechanical advantage.

Accordingly, this invention provides a hand tool comprising a handle, a body, rotatable first and second shafts, and a gearing arrangement giving a rotational speed advantage from the first shaft to the second shaft and a mechanical advantage from the second shaft to the first shaft, the hand tool being such that the handle can be positioned on either of the first and second shafts to obtain either the rotational speed advantage or the mechanical advantage.

In one embodiment of the invention, the first and second shafts extend from the body and terminate in heads which are adapted to fasten and unfasten screws, the hand tool then constituting a screw driver.

In another embodiment of the invention, the first and second shafts extend from the body and terminate in heads which are adapted to receive means for fastening and unfastening nuts, the hand tool then constituting a spanner.

In a further embodiment of the invention, the first and second shafts each terminate in a socket device, one of the socket devices being adapted to receive a drill bit and the hand tool then constituting a sweep brace.

Preferably, the first and second shafts are axially in line. However, if desired, the first and second shafts may extend through an angle. By way of example only, it is mentioned that the angle may be a right angle.

The handle may be in various shapes. It may thus be round, oval or bar-shaped.

Preferably, each of the first and second shafts is associated with a pair of gears. If desired however, each of the first and second shafts may only have one gear or they may be associated with more than two gears.

Advantageously, the first and second shafts turn in bearings in the body. These bearings may be made of phosphor bronze. Obviously, other bearing materials may be employed if desired, for example steel.

Embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 shows a basic construction of hand tool in accordance with the invention and it is given for the purpose of illustrating the operating principle; Figure 2 is a section on the line A-A; Figure 3 is a section on the line B-B; Figure 4 is a longitudinal cross section through a screw driver in accordance with the invention; Figure 5 shows part of the handle employed in Figure 4; Figure 6 is an end cross section of the screw driver shown in Figure 4 Figure 7 is a cross section on the line A-A shown in Figure 6; Figure 8 is a cross section through parts of a sweep brace in accordance with the invention; Figure 9 is a detail of parts of the sweep brace shown in Figure 8;; Figure 10 is a perspective view of the sweep brace illustrated in Figure 8; Figure 11 is an end view of a modified sweep brace acting as a screwdriver; and Figure 12 shows a gearing arrangement.

Referring to Figures 1, 2, and 3, there is shown the basic construction of a hand tool 2 comprising a bar handle 4, a first rotatable shaft 6, a second rotatable shaft 8, and a gearing arrangement 10. The gearing arrangement 10 comprises four intermeshing gear wheels Ni, N2, N3 and N4. The gearwheel N1 is positioned on the shaft 6 and the gear wheel N4 is positioned on the shaft 8. The gear wheels N2 and N3 are joined by a short shaft 12.

If the shaft 6 is rotated with the handle 4, this will cause the gear wheel N1 to rotate and, by virtue of the entire gearing arrangement 10, the gear wheel N4 and its associated shaft 8 will rotate. By way of example only it is mentioned that if the gear wheel N1 has 60 teeth and the gear wheel N2 has 20 teeth, then the rotation of the gear wheel Ni will activate N2 three times greater than the gearwheel Ni or 60/20 = 3.

Similarly, N3/N4 = 60/20 which activates the shaft 8. Since the gear wheel N3 is travelling at three times its normal rate, the final speed of the shaft 8 will be 9.

Considering velocity ratio for one rotation of the shaft 6, the following is obtained: Velocity Rates = N2 x N4 N4 60 60 = 60 x 60 = 9 20 20 Considering velocity ratio when associated with the shaft 8, if this shaft 8 is rotated once then the speed of shaft 6 will be as follows: N4 N2 Velocity Ratio =N3 x Ni 20 20 1 60 60=9 It will be apparent from the above that the rotation from shaft 6 gives a high velocity ratio causing the shaft 8 to turn 9 times faster than the shaft 6. Conversely if the shaft 8 is rotated the shaft 6 rotates at 1/9 of the speed but it has a high mechanical advantage. When the shaft 8 rotates faster than the shaft 6, it will be apparent that screws and bolts can be tightened up much faster than hitherto and holes can be drilled quickly.When the shaft 6 rotates slower than the shaft 8 then it will be apparent that large and difficult screws and bolts can easily be inserted or withdrawn with a reduced effort.

Referring now to the Figures 4 to 7, there is shown a screwdriver 2 embodying the basic principles of the hand tool illustrated in Figures 1 to 3. In Figures 4 to 7 similar parts as in Figures 1 to 3 have been given the same references.

In Figures 4 to 7 the handle 4 of Figures 1 to 3 has been replaced by an oval type handle 4 and the gearing arrangement 10 has been housed in a body 14 which is preferably made of a moulded plastics material. The body 14 may be provided with an optional lever extension 16.

In all the Figures 1 to 7, the ends of the shafts 6 and 8 are square so that the handles 4 can be fitted on the end of the shaft 6 or the end of the shaft 8 depending upon whether an increased velocity ratio or an increased mechanical advantage is required. In the embodiment illustrated in Figures 1 to 7, the end 18 of the shaft 8 terminates in a chamfered thin portion for engaging in the slotted head of screws.

In Figure 4to 7, the shaft 6 turns in a bush 20 and the shaft 8 turns in a bush 22. The bushes 20 and 22 are located in the body 14 and they may be made, for example, of steel or phosphor bronze.

Referring now to Figures 8 to 10, the basic hand tool illustrated in Figures 1 to 3 has been formed into a wheel brace. Similar parts in Figures 1 to 3 have been given the same references in Figures 8 to 10.

In Figures 8 to 10, the shafts 6, 8 terminate in socket members 24,26 respectively. The socket members 24, 26 are each provided with sockets 28 and these sockets are adapted to receive a part circular bar 30 which is secured into position in its socket 28 by means of an Allen screw 32. The bar 30 can then receive a handle 4 so that either end of the hand tool can be used as the handle end. The socket 26 remote from the handle end can then receive a drill bit 34 as shown most clearly in Figure 10. Also as shown most clearly in Figure 10, the handle is formed as a wheel handle 36 having an elongate arm 38 and a rotatable handle member 40.

In Figures 8 to 10, the gearing arrangement 10 has the gears N1, N2, N3, N4formed as bevel gears and there are two further bevel gears N5 and N6. The bevel gear N5 rotates a shaft 42 and the bevel N6 rotates a shaft 44. The shafts 42 and 44 terminate in socket members 46, 48 respectively which are constructed and operate the same as the socket members 24, 26. All the socket members 24, 26, 46 and 48 rotate in bearings 20 which can be made of steel or phosphor bronze.

In Figure lithe wheel brace illustrated in Figures 8 to lOis shown modified to the extent that the drill bit 34 has been replaced by a screwdriver shaft 50 and this is being rotated in the socket device 46 or 48. The shaft 50 is shown operating on a screw 52.

Referring now to Figure 12 the gearing arrangement illustrated in Figure 1 has been modified in that a further gear wheel N7 has been inserted between the gear wheels N1 and N2. The gear N7 acts as a reversing cog to reverse the direction of rotation of the shaft Sin Figure 12 from that which occurs in the arrangement illustrated in Figure 1. Obviously, in hand tools, a reversal of a tightening action is required for an untightening action.

It is to be appreciated that the embodiments of the invention described above have been given by way of example only and that modifications may be effected. Thus, for example, box spanners could be used in place of the drill bit and screwdriver shaft illustrated. Also, with other appropriate devices, the hand tool 2 could be used as a paint stirrer or as a sander. Also, referring Figure 10, with a different type of handle 36 and a different type gearing arrangement 10, the wheel brace 2 could be used as a hand drill. Advantageously, the body 14 is moulded in two parts and, if desired, the bearings 20 can be ball bearings. The illustrated gearing arrangements can be replaced by a planetary gear system. With a planetary gear system, the body of the hand tool may be internally splined to act as the larger gear wheel.

The present invention also extends to all the above described parts of the invention taken singly and in any combination.

Claims (10)

1. A hand tool comprising a handle, a body, rotatable first and second shafts, and a gearing arrangement giving a rotational speed advantage from the first shaft to the second shaft and a mechanical advantage from the second shaft to the first shaft, the hand tool being such that the handle can be positioned on either of the first and second shafts to obtain either the rotational speed advantage or the mechanical advantage.

2. A hand tool according to claim 1 in which the first and second shafts extend from the body and terminate in heads which are adapted to fasten and unfasten screws, the hand tool then constituting a screw driver.

3. A hand tool according to claim 1 in which the first and second shafts extend from the body and terminate in heads which are adapted to receive means for fastening and unfastening nuts, the hand tool then constituting a spanner.

4. A hand tool according to claim 1 in which the first and second shafts each terminate in a socket device, one of the socket devices being adapted to receive a drill bit and the hand tool then constituting a sweep brace.

5. A hand tool according to any one of the preceding claims in which the first and second shafts are axially in line.

6. A hand tool according to any one of claims 1 to 4 in which the first and second shafts extend through an angle.

7. A hand tool according to any one of the preceding claims in which the handle is round, oval or bar-shaped.

8. A hand tool according to any one of the preceding claims in which the first and second shafts turn in bearings in the body.

9. A hand tool according to claim 8 in which the bearings are phosphor bronze or steel bearings.

10. A hand tool substantially as herein described with reference to the accompanying drawings.