GB2195155A

GB2195155A - Shaft brake assembly, particularly for use in a wheel balancing apparatus

Info

Publication number: GB2195155A
Application number: GB08721021A
Authority: GB
Inventors: Richard James Cullen; Willy Borner; Bernard Jackson
Original assignee: SHANNON RES Ltd
Current assignee: SHANNON RES Ltd
Priority date: 1986-12-03
Filing date: 1987-09-07
Publication date: 1988-03-30
Anticipated expiration: 2007-09-07
Also published as: IE862407L; GB2195155B; GB8721021D0; BE905975A; IE59383B1

Abstract

The wheel balancing apparatus (1) comprises a base member (2), an upstanding column (3), and a housing (4). A shaft (7) rotatable in the housing (4) carries a hub (6) mounted fast thereon for receiving a wheel to be balanced. The brake assembly (32) for braking the shaft (7) comprises a brake member constituted by a pair of clamping members (34), which are retained on the shaft (7) with a friction grip force. A stop member (40) is pivotal by a handle (44) from a position disengaging the clamping member (34) to a position engaging the clamping member (34) to stop rotation of the clamping members (34), and in turn to bring the shaft (7) to rest as a result of the friction grip acting between the clamping members (34) and the shaft (7). Other forms of brake member and stop member are disclosed. <IMAGE>

Description

SPECIFICATION Wheel balancing apparatus The present invention relates to wheel balancing apparatus, and in particular to a shaft brake assembly for use in the wheel balancing apparatus. It also relates to a column support for the wheel balancing apparatus. Needless to say, the shaft brake assembly and indeed, the column support could be put to other uses.

According to the invention there is provided a shaft brake assembly comprising a brake member mounted on the shaft, and tightly gripping the shaft with a friction grip, and stop means mounted on a housing in which the shaft is rotatable, the stop means being movable from a position disengaging the brake member to a position with the stop means engaging the brake member. In one embodiment of the invention, the brake member is symmetrical about the shaft. preferably, the brake member is provided by a pair of clamping members one on each side of the shaft, retaining means being provided to retain the clamping members together. Advantageously, the retaining means is adjustable to vary the clamping pressure between the clamping members and the shaft.

Additionally, the invention provides wheel balancing apparatus comprising the shaft brake assembly of the invention. Preferably, a housing is provided to house the shaft brake assembly, the shaft being rotatably mounted in the housing. Advantageously, the housing is supported on a support column comprising an upstanding column supported on a base member. Preferably, the upstanding column is releasably secured to the base member.

The invention will be more clearly understood from the following description of a preferred embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of wheel balancing apparatus according to the invention, Fig. 2 is a perspective view of the apparatus of Fig. 1 from a different direction, Fig. 3 is a perspective view of portion of the apparatus of Fig. 1, Fig. 4 is a perspective view of a detail of the portion of the apparatus of Fig. 3, Fig. 5 is a perspective view of another portion of the apparatus of Fig. 1, Fig. 6 is a perspective view of the portion of Fig. 5, Fig. 7 is a further perspective view of the portion of Fig. 5, Fig. 8 is a cross-sectional view of a detail of the apparatus of Fig. 1, Fig. 9 is an exploded view of the detail of Fig. 8, Fig. 10 is a side view of a detail of the apparatus of Fig. 1, Fig. 11 is a further side view of the detail of Fig. 10, and Fig. 12 is a still further side view of the detail of Fig. 10. Referring to the drawings, there is illustrated wheel balancing apparatus according to the invention, indicated generally by the reference numeral 1. The wheel balancing apparatus comprises a base member 2 supporting an upstanding column 3, which in turn supports a housing 4. A hub 6 to receive a wheel to be balanced is fast on a shaft 7 which is rotatably mounted and suspended within the housing 4 on brackets 8. The housing 4 and shaft 7 are described in more detail below.

The base member 2 is formed by a pressing of sheet metal material. Three ground engaging feet 9 of hollow box section material are welded to the base 2. The fact that only three feet 9 are provided accommodates uneven floor surfaces. A reinforcing sheet 10 in the lower part of the base member 2 provides for torsion stability of the base 2. A reinforcing plate 11 of metal plate material is welded to the base member 2 to support the upstanding column 3; The upstanding column 3 is of sheet metal material formed in two portions 12 formed by bending two sheets of sheet metal at 14 and welding the portions 12 at 13. Four screws 15 welded to the inner lower portion of the upstanding column 3 engage corresponding holes 16 in the reinforcing plate 11. Nuts 17 and washers 18 releasably secure the upstanding column 3 to the base member 2.A plate member 19 of metal plate material is welded to the top of the upstanding column 3 to releasably support the housing 4. Slots 20 and a keyhole slot 21 are provided in the plate 19 to releasably accommodate screws 22 extending from the housing 4. An opening 23 in the rear wall 24 of the upstanding column 3 allows access to the lower side of the plate 19 for tightening the screws 22 for securing the housing 4.

The housing 4 is formed from an aluminium casting 26, in this case pressure die cast. The shaft 7 is supported on a floating assembly 25 so that the out of balance moment of a rotating wheel on the hub 6 may be measured. Such floating assemblies will be well known to those skilled in the art, and it is not intended to describe the floating assembly further. Suitable monitoring apparatus for monitoring the out of balance moment is also mounted in the floating assembly. A visual display unit 27 in a display panel 28 is provided to display the out of balance moment, the value of the weight required to rectify the out of balance moment and the position where the weight should be mounted on the wheel rim. A rear portion 30 of the shaft 2 is of reduced diameter.A shaft brake assembly 32 according to the invention is mounted on the portion 30 of the shaft 7 for stopping the shaft after the out of balance moment of the wheel (not shown) has been determined.

The brake assembly 32 comprises a brake member 33 which comprises a pair of clamping members 34 of semi-circular cross-section and of phosphorbronze material. End portions 35 extend from the clamping members 34 for securing the members 34 together. Adjustable retaining means provided by screws 37, nuts 38 and washers 39 secure the clamping members 34 together. The screws and nuts 37 and 38 are tightened so that the clamping members 34 tightly engage the shaft 7 with a friction grip. The friction grip is increased or decreased by tightening or loosening respectively the screws 37 and nuts 38. When the shaft 7 is rotating normally, the clamping members 34 of the brake assembly 32 rotate with the shaft. The brake assembly 32 is symmetrical on the shaft 7 and this avoids the need to balance the brake mechanism.A stop means provided by a stop member 40 of nylon material fast on a pivot shaft 41 which its pivotal in a hole 42 in the housing 4 is movable from a position illustrated in Fig. 12 where the stop member 40 is out of engagement with the clamping member 34 to the position illustrated in Figs. 6 and 8 in which the stop member 40 engages the clamping members 34 to stop the shaft 7. A handle 44 extending from the pivot shaft 41 operates the stop member 40. As can be seen in Fig.

11 the handle 44 comprises a knob 45, which is arranged to pivot the stop member 40 under gravity into the position illustrated in Fig.

12 out of engagement with the clamping member 34.

Thus, when it is desired to brake the shaft 7, the stop member 40 is pivoted by the handle 44 into the position illustrated in Figs.

6 and 8, and accordingly, engages one of the screws 37 to prevent the clamping members 34 rotating with the shaft. Due to the friction grip between the clamping members 34 and the portion 30 of the shaft 7, the shaft is quickly brought to rest. It has been found that where a shaft rotates at approximately 90 revolutions per minute, the shaft can be brought to rest in threequarters of a revolution when the screws 37 and nuts 38 are tightened, so that the friction grip exerted by the clamping members 34 on the shaft 7 is sufficient.

In use, the wheel balancing apparatus is initially assembled. This can be readily easily achieved by mounting the upstanding column 3 on the base member 2, and securing it with the screws 15 and nuts 17. The housing 4 is in turn mounted on the plate 19 on top of the upstanding column 3.

A wheel (not shown) to be balanced is secured to the hub 6, and the shaft 7 is rotated.

The wheel is rotated by hand to a speed of approximately 90 revolutions per minute. The value of the out of balance moment and its position on the wheel is then monitored and displayed on the visual display unit 27. Both the value of the out of balance moment and its position on the wheel are monitored by the apparatus in the floating assembly 25. When the details of the out of balance moment have been displayed, rotation of the shaft 7 is stopped by braking the shaft 7 with the shaft brake assembly 32. The stop member 40 is pivoted in the direction of the arrow A by the handle 44, so that the stop member 40 engages one of the screws 37 of the clamping members 34. On engagement by the stop member 40, the clamping members are immediately stopped, and the frictional grip between the clamping members 34 and the portion 30 of the shaft 7 bring the shaft 7 to rest.As already mentioned, in general, the shaft will be brought from 90 revolutions per minute to rest in about three-quarters of a revolution.

When the shaft has been brought to rest, the braking force is thus removed between the clamping member 34 and the stop member 40, and accordingly, under the gravitational force exerted on the knob 45 and handle 44, the stop member 40 is pivoted into the position of Fig. 12 in the direction of the arrow B, and thus disengages the clamping members 34, so that apparatus is ready for the next wheel.

It will be appreciated that while the shaft brake assembly has been described for use in wheel balancing apparatus, it could be put to many other uses without departing from the scope of the invention. For example, it is envisaged that it may be used as a shaft brake on, for example, a lathe, a milling machine, indeed, in certain cases, it may even be used as a shaft brake on a road vehicle. Needless to say, the frictional gripping force between the clamping members would be varied if it were to be used on a road vehicle to provide adequate stopping distance.

It will be appreciated that while a particular type of brake member, in other words, the two clamping members have been described, any other suitable brake member could be used. For example, a pair of clamping members which might only engage small areas of shaft could be used. In other cases, it is envisaged that a plurality of clamping members could be used, while in other cases, it is envisaged that a single clamping member may be used. Needless to say, any other combinations of brake members or constructions of brake members will be readily apparent to those skilled in the art. Indeed, where the brake member is provided as a single member, it is envisaged that a circular hole would be provided in the member to engage the shaft with a friction grip, and a radial slot would be provided in the member extending from the hole to the periphery of the member. A nut and screw arrangement or any other fastening arrangement may be provided across the radial slot for tightening the frictional grip of the braking member on the shaft, should this be required.

Further, it will be appreciated that while the stop member has been described as being pivotal, this is not necessary, it could be movable by any means or in any way. Needless to say, other suitable stop means could be used, without departing from the scope of the invention.

It will also be appreciated that the stop means may be operable other than a handle arrangement for pivoting the stop means. Indeed, in certain cases, the stop means may be driven by any suitable drive means, such as, for example, a ram, either pneumatic or hydraulic, a solenoid, an electric motor, linear motor, or the like.

Further, it will be appreciated that while the retaining means to retain the clamping members together have been described as being screws which provide effective adjustment for the retaining means, to permit the frictional gripping force between the clamping members of the shaft to be adjusted, any other suitable retaining means could be provided Indeed, it is not necessary that the retaining means should be adjustable at all. Other adjustable retaining means which may be provided, could for example, be provided by rams, either hydraulic or pneumatic, solenoids, linear motors or the like. In fact, as already mentioned, where a single brake member is provided, it is envisaged in certain cases a retaining means may not be required.

Further, while a particular construction of column and base, and indeed, housing have been described in the wheel balancing apparatus, any other suitable construction could be used without departing from the scope of the invention. Further, materials other than sheet metal or cast iron may be used in the construction of the column, base and housing respectively. However, it will be appreciated that a particular advantage of the present construction is that it provides a relatively lightweight apparatus, as well as being relatively inexpensive, and also in particular, it provides for wheel balancing apparatus which can be readily easily assembled and disassembled, which leads to ease of transportation and shipment, and accordingly, further reduces the cost of the apparatus.

Needless to say, while the column, base and housing have been described as being releasably mounted together, this is not necessary, nor is it essential.

Further, while the brake assembly has been described as being symmetrically mounted around the shaft 7, while this is preferable in that it avoids the need to balance the shaft, it is not essential. If the brake member were not symmetrical, then the shaft with the brake in place could be balanced.

Claims

1. A shaft brake assembly comprising a brake member mounted on the shaft, and tightly gripping the shaft with a friction grip, and stop means mounted on a housing in which the shaft is rotatable, the stop means being movable from a position disengaging the brake member to a position with the stop means engaging the brake member.

2. A shaft brake assembly as claimed in Claim 1 in which the brake member is symmetrical about the shaft.

3. A shaft brake assembly as claimed in Claim 1 or 2 in which the brake member is provided by a pair of clamping members one on each side of the shaft, retaining means being provided to retain the clamping members together.

4. A shaft brake assembly as claimed in Claim 3 in which the retaining means is adjustable to vary the clamping pressure between the clamping members and the shaft.

5. A shaft brake assembly as claimed in Claim 3 or Claim 4 in which the retaining means is provided by a pair of nuts and bolts on opposite ends of the clamping members, so that by tightening or loosening the nuts, the clamping pressure is varied.

6. A shaft brake assembly as claimed in any of Claims 3 to 5, in which each clamping member is provided by a shell of semi-circular cross-section.

7. A shaft brake assembly as claimed in Claim 6 in which the free ends of each shell extend outwardly to substantially abut each other for engagement of the retaining means.

8. A shaft brake assembly as claimed in any of Claims 3 to 7, in which the clamping members are of phosphorbronze material.

9. A shaft brake assembly as claimed in any preceding claim in which the stop means is provided by a stop member pivotally mounted in the housing.

10. A shaft brake assembly as claimed in Claim 9 in which the stop member is of nylon material.

11. A shaft brake assembly as claimed in Claim 9 or Claim 10 in which a handle is provided to pivot the stop member from one position to the other.

12. A shaft brake assembly as claimed in Claim 11 in which the handle is arranged to pivot under gravity to the position in which the stop member disengages the brake member.

13. Wheel balancing apparatus comprising the shaft brake assembly of any of Claims 1 to 12.

14. Wheel balancing apparatus as claimed in Claim 13 in which a housing is provided to house the shaft brake assembly, the shaft being rotatably mounted in the housing.

15. Wheel balancing apparatus as claimed in Claim 14 in which the housing is supported on a support column comprising an upstanding column supported on a base member.

16. Wheel balancing apparatus as claimed in Claim 15 in which the upstanding column is releasably secured to the base member.

17. Wheel balancing apparatus as claimed in Claim 15 or 16 in which the upstanding column is secured to the base member by screws.

18. Wheel balancing apparatus as claimed in any of Claims 15 to 17 in which the base member is supported on three spaced apart ground engaging feet.

19. Wheel balancing apparatus as claimed in any of Claims 14 to 18 in which the housing is releasably mounted to the upstanding col umfl.

20. Wheel balancing apparatus as claimed in Claim 19 in which a plate member is provided on the top of the upstanding column to support the housing.

21. Wheel balancing apparatus as claimed in any of Claims 13 to 20 in which the upstanding column is of hollow rectangular section formed of sheet metal material.

22. Wheel balancing apparatus as claimed in any of Claims 15 to 21 in which the base member is of sheet metal material.

23. Wheel balancing apparatus as claimed in Claim 22 in which a reinforcing plate is provided on the base member to support the upstanding columns.

24. A shaft brake assembly substantially as described herein with reference to and as illustrated in the accompanying drawings.

25. Wheel balancing apparatus substantially as described herein with reference to and as illustrated in the accompanying drawings.