GB2040770A - Vehicle wheel nut spanner - Google Patents

Abstract

A spanner enables the wheel nuts of a motor vehicle to be tightened with the torque prescribed by the manufacturer. The spanner has a box spanner part (11) a lever (1) connected thereto, and a peg which is attached to the lever so as to project axially parallel, but in the opposite direction to the box spanner part. When tightening a wheel nut the operator stands with his full weight on the peg. To enable persons of differing body weights to achieve the same prescribed tightening torque, the radial distance between the box spanner part and the peg is varied. For this purpose, either the box spanner part (10) or the peg is displaceable relative to the lever. A lever scale determines the relative box spanner and peg positions for required torque, the spanner or peg being locked against movement. <IMAGE>

Description

SPECIFICATION Tool particularly for vehicle wheel nuts Field of the invention The present invention relates to a tool particularly but not exclusively for loosening or tightening wheel nuts of motor vehicles.

Background to the invention A tool required for changing the wheels is supplied by the manufacturer with every motor vehicle.

This so-called service tool generally comprises a multi-purpose tool which, on throne hand, serves to operate the vehicle jack and, on the other hand, to loosen the wheel nuts.

Generally, it is only possible for physically strong persons to change a wheel by means of the service tool. Wheel nuts tightened by means of compressedair tools are usually screwed on too tightly. Manual tightening of the screws presents a second difficulty.

Some automobile manufacturers give precise details with respect to the torque with which the nuts should be tightened. An average value is about 12 mkg.

It is known among experts that top little attention is given to the tightening of wheel nuts. Non-uniform tightening of the wheel nuts causes distortion of the wheel rim. However, since the wheels are balanced when in the non-mounted state, non-uniform tightening of the wheel nuts causes wobbling of the wheels.

Prior art Spanners for wheel nuts which, in particular, facilitate the loosening of the wheel nuts, are commercially available. These spanners are the so-called cross spanners (comprising two crosswise interconnected spanners) and to so-called angled spanner. Both of these types of spanner are more conveient than the conventional service tool and permit better transmission of force. Furthermore, various types of torque wrenches are commercially available, although these are not suitable for the purpose described above.

Object of the invention An object of the present invention is to provide a tool, particularly a wheel nut spanner, which renders it possible, in a simple manner, readily to loosen wheel nuts and to tighten them in accurately defined manner with a torque prescribed by the manufacturer.

The invention This object is achieved by a tool having a nut engaging member and a lever connected thereto which is characterised in that a peg member is attached to the lever so as to project axially parallel, but in the opposite direction, to the nut engaging member, one of the members being adjustable to vary the distance between the nut engaging member and the peg member and the adjustable member being securable in different positions.

Basically, there are to possible embodiments, Either the nut engaging member is fixed on the lever and the peg member is displaceable relative to the lever, or the peg member is fixed on the lever and the nut engaging member is displaceable relative to the lever.

The peg member may be in the form of a bolt which may or may not be threaded and the nut engaging member may be a ring or box spanner part having a nut receiving recess.

By way of example, these two embodiments of the invention are illustrated in the drawings.

In the drawings Figure 1 shows a tool having a peg member which is displaceable on the lever; Figure 2 shows the peg member and its sliding member, drawn to a larger scale; Figure 3 is a plan view of a tool having a nut engaging member which is displaceable on the lever, and Figure 4 is a front elevation of the tool of Figure 3.

Detailed description of the drawings The tool of Figures 1 and 2 has three main parts. A sliding member 2 is displaceable mounted on the arm 12 of the spanner generally designated 1. A telescopic extension piece 3 can be slipped onto the arm 12. The spanner 1 comprises a box spanner part 11 having a dodecahedral recess and the lever 12 angled through 90". The box spanner 11 is rigidly connected to or integrally formed with the lever 12.

The lever 12 is made from steel and has a square cross section. The side face 13 is' provided with a scale 14. The side face 15 incorporates bores (not illustrated) for locking the sliding member 2.

The sliding member 2 is manufactured from a square section tubular member 21. The sloping cut face 22 renders it possible to push the sliding member as near as possible to the bend in the lever 12. This is important, since the sliding member has to be adjusted according to the body weight of the user. With a body weight of 100 kg, the bolt 23, on which the user stands with his full weight, must be only 12 cm from the axis of rotation of the wheel nut if wheel nut is to be tightened with a torque of 12 mkg. Owing to the scale 14, the user only has to displace the sliding member to the extent that his body weight in kilograms, rounded up to the nearest ten, appears in the window 24. When he then stands on the bolt 23, the wheel nut is tightened with the correct torque.The sliding member has to be lockable to prevent it from being displaced when turning the spanner. The locking device of Figure 2 has a locking dog 25 which extends through a bore 26 and which is secured to a spring plate 27 which is welded at one end to the sliding member 2. The dog 25 engages a corresponding blind bore in the lever 12 and can be engaged and disengaged by means of the operating knob 28.

The extension piece 3 is only required for loosening the wheel nuts. A square section tube 31, whose internal dimensions are equal to those of the sliding member 2, can be mounted on the lever 12. A square section bar 32, having the same dimensions as those of the lever 12, is telescopically displaceable mounted on the tube 31. The length of the extension can thus be adapted to the force applied by the user.

Various modifications are possible within the ambit of the invention. It can be advantageous for the box spanner part 11 to be interchangeable for use in workshops. Commercially available box spanner inserts can be interchanged when a square section bar of the correct size is used for the lever 12.

Alternatively, the spanner can be in the form of a ring spanner.

Instead of being locked by means of an engaging dog, the sliding member can be locked by means of a setscrew. A particularly inexpensive solution resides in providing the lever 12 and the sliding member 2 with through bores, so that it is only necessary to bring the bores into register and then to push a loose bolt 23 through the two parts. It is then also possible to omit the sliding member, provided the bores are labelled with scale values. Finally, the scale need not be read through a window, and can for example be read at the rear edge of the sliding member, in which event the scale 14 is correspondingly shifted. It will also be appreciated that, the scale can be adapted to some other system of measuring.

The spanner of Figure 3 and 4 has a box spanner part 10 which is displaceable along a lever 20. A bore, 101 having the cross sectional dimensions of the lever 20 is provided through the box spanner part 10 at right angles to the longitudinal axis thereof. In the same manner as a commercially available box spanner, the box spanner part is provided with a hexagonal or dodecahedral recess 102. To avoid undue weakening of the cylindrical metal part of the box spanner part 10 by the through bore 12, the external diameter of the cylindrical metal part is constant over its entire length. A set screw 103 is provided as a locking element for the hexagonal recessed member 102. The set screw 103 is located exactly in the longitudinal axis of the box spanner part 10 and extends into the through bore 101.When the spanner is ready for use, the set screw 103 presses against the lever 20 which has been pushed through the bore 101, and thus fixes the position of the box spanner part 10on the lever 20 relative to the bolt 30.

The lever 20 has a square cross section. A bolt 30 is secured in one end region of the lever 20 at right angles to the longitudinal axis thereof. Aweight scale 262 is embossed on one side face 201 of the lever. This scale indicates the position in which the box spanner part 10 has to be locked on the lever 20 in order that a wheel screw can be tightened with the correct torque (12 mkg in the present instance) buy a person of appropriate body weight (70 kg in the present instance) who is standing on the bolt 30. As already mentioned initially, the absolute accuracy of the tightening torque is of less importance than in the application of an equal torque to all the nuts of a wheel.

Indentations 204 are provided in the side face 203 in order to ensure improved locking by means of the setscrew 103.

When a vehicle is provided with a service tool constructed as an embodiment of the invention a single scale, conforming to the manufacturers instructions with respect to that particular vehicle wheel nut torque, is sufficient. These torque data vary to a considerable extent according to the type and model of vehicle. For example the tightening torque for Peugeot and Citroen passenger cars is 6mkg, while 10 mkg torque is prescribed for Mercedes-Benz and Audi passenger cars.

If the spanner is to be produced for the car accessory trade, each of the four side faces of the lever can be provided with a different scale corresponding to the torque, in order to meet, as far as possible, all requirements. It is then necessary to be able to mount the bolt 30 on four sides of the lever 21. This can be realised by providing the bolt 30 with a screw thread and providing the lever 20 with complementary screw-threaded holes.

Figure 3 shows a particularly advantageous solution which enables the spanner to be provided with two different scales (only one of which is visible in the drawing). In this instance, the two scales 202 have been engraved on mutually opposite side faces of the lever 20. The bolt 30 can be mounted in a single through bore 205. In order to prevent the bolt from slipping out, it has a stop 301, in the form of a thickened portion, at each end. Depending on which of the two scales it is desired to use, it is only necessary to remove the box spanner part 10 and to push it onto the lever 20 the other way round, and to push the bolt 30 through to the other stop 301.

In order to loosen the wheel nuts, a tube (not illustrated in the drawing), whose internal dimensions correspond to the cross section of the lever 20, can be mounted on the end of the lever 20, whereby the lever arm is extended and, consequently, the force required to loosen the wheel nuts is reduced.

It will be appreciated that other possibilities of locking can be realised in addition to the type of locking arrangement illustrated. By way of example, locking can be effected by means of a resilient adjusting pin, as is illustrated in Figures 1 and 2.

When using the spanner, the box spanner part 10 is first displaced such that its left hand edge points to the approximate weight of the user on the scale 202.

The setscrew 103 is then tightened and the spanner is fitted onto the wheel nut. The nut will then be accurately tightened with the desired torque when the user stands with his full body weight on the bolt 30.

Claims (10)

1. Atool, particularlyforthe loosening and tightening of wheel nuts of motor vehicles having a nut engaging member and a lever connected thereto, characterised in that a peg member is attached to the lever so as to project axially parallel, but in the opposite direction, the the nut engaging member one of said members being adjustable to vary the distance between the nut engaging member and the peg member and the adjustable member being sect rabble in different positions.

2. Atool as claimed in claim 1, characterised in that the nut engaging member is rigidly connected to a lever which has a rectangular cross section, and that the peg member is connected to a sliding member which is displaceable and lockable on the lever.

3. Atool as claimed in claim 1, characterised in that the peg member is rigidly connected to a lever which has a rectangular cross section, and that the nut engaging member is arranged on the lever so as to be displaceable and lockable thereon.

4. Atool as claimed in claim 1, characterised in that a weight scale corresponding to a specific tightening torque is provided on the lever.

5. Atool as claimed in claim 1, characterised in that a set screw is provided as a locking element.

6. Atool as claimed in claim 1, characterised in that a resilient adjusting pin is provided as the locking element and engages a locking bore provided in the lever.

7. Atool as claimed in claim 1, characterised in that a window for reading the weight scale is provided in the sliding member.

8. Atool as claimed in claim 1, characterised in that the lever is provided with more than one weight scale in conformity with the different tightening torques.

9. A tool as claimed in claim 1, characterised in thatthe nut engaging member is rigidly connected to the lever which is provided with a row of bores, and that the peg member can be selectively inserted or screwed into one of these bores.

10. Atool for tightening or loosening vehicle wheel nuts constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in Figures 1 and 2 or Figures 3 and 4 of the accompanying drawings.