AU651393B2 - An improved brake assembly - Google Patents

Description

COMMONWEALTH OF AUSTRALIA Patents Act 1990 1 L *4 t 4 4 1* 9 £4 4 I 4 4 .4 £4 £04 *44 9 4 4 4 4.

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I 4 4 444 4 44~£J 4 4444 4444 4, 4 44 BARTLEM PTY LTD (Patent Application No. PK3243) COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED:- "AN IMPROVED BRAKE ASSEMBLY" The following statement is full description of this invention, including the best method of performing it know to us: rr 1 "AN IMPROVED BRAKE ASSEMBLY" This invention relates to an improved brake assembly.

This invention is particularly applicable to btakes for rider mowers but of course it is to be understood that it can be utilized in other applications such as golf buggies, as desired, For illustrative purposes however, this invention will now be described with reference to the application of the brake assembly to rider mowers.

Rider mowers are often operated on sloping ground and thus it is essential that there be provided suitable means for 10 holding a parked mower on a slope. Accordingly a brake is normally provided for general operation of the rider mower as well as a brake for parking.

Such rider mowers may be operated by unskilled persons and it has been found that parking brakes are often left engaged 15 during normal operations and thus made ineffective. This may lead to dangerous situations occurring, of which the operator may be unaware. Furthermore, the complexity of twin braking systems, that is one for parking and one for driving, adds markedly to the cost of manufacture of a rider mower.

This invention aims to alleviate the abovementioned disadvantages and to provide a brake assembly which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent.

With the foregoing and other objects in view, this invention in one aspects resides broadly in actuating means for actuating a brake assembly, the actuating means including:= IT1 'q 0Q ~PY~7A

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2 a brake link member moveable from an inoperative position to actuate said brake assembly, and a manual or foot operable member pivotable for effecting camming engagement between the manual or foot operable member and the brake link member, said camming engagement causing operative movement of said brake link member.

The manual or foot operable member may be adapted to pivot the link member for actuating a brake assembly or it may be adapted to linearly move the link member for actuating a brake 10 assembly. Preferably, the manual or foot operable member is pivotable whereby substantially maximum resultant movement of said link member from its inoperative position occurs when the o'o manual or foot operable member is in a over-centre position and stop means are provided to limit pivotal movement of the manual 15 or foot operable member beyond an over-centre position substantially corresponding to maximum resultant movement of o said link member.

aoo In a further aspect this invention resides broadly in a brake assembly including:a rotary member to be braked; a pair of opposed braking shoes pivotally connected together about a fixed pivot assembly for pivotal movement between an engaged attitude engaged with the rotary member and disengaged attitude operatively spaced from the rotary member; supporting members on each shoe remote from the fixed pivot assembly and arranged in spaced apart relationship whereby they may be moved together to pivot the braking shoes to the L A 3 engaged attitude; a linkage assembly linking said supporting members whereby they may be moved together to pivot the braking shoes to the engaged attitude, the linkage assembly including a linkage link member, and being operable for moving said braking shoes to said engaged attitude actuating means for actuating said linkage link member, the actuating means being substantially as defined above.

The braking shoes may be external shoes of a contracting 10 drum brake or they may be internal shoes of an expanding drum brake. Alternatively the braking shoes may be pads of a disc brake assembly. Suitably, spring means are provided whereby the t braking shoes are be held in a non-operative position unless the l"-,cls:r is actuated, and whereby the braking shoes may return to a 15 inoperative position when the operating member is released.

It is also preferred that the link member be arranged whereby its operative movement pivots a cam member adapted to 4 4: draw the braking shoes towards one another about the rotary r member and for this purpose the cam member and the link member may constitute interconnected members of an actuating linkage assembly. The latter may include return spring means for biassing the link member to its inoperative position and for biassing the operating member to brake locking over-centre position.

In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrates a typical 4 embodiments of the invention, and wherein:- FIG 1 illustrates the brake assembly in the engaged attitude; FIG 2 illustrates the brake assembly in the disengaged attitude, and FIG 3 illustrates a further brake actuator assembly.

As shown, the brake assembly 10 is a contracting drum brake assembly having a pair of opposed braking shoes 11 and 12 interconnected by a adjustable pivot arrangement 13 whereby the shoes 11 and 12 may be arranged concentrically about the drum 14 which is fixed to the shaft 15 to be braked. Each shoe includes a fabricated backing strip 16 which is welded to a respective to pivot plate 17 to extend partway around the drum 14 and, opposite the pivot 13, outwardly at 18 and 19 so as to form mounting lugs for the actuating linkage assembly The actuating linkage assembly 20 includes a lever 21 provided with an end flange 22 which extends substantially .Lre parallel to the lugs 18 and 19 and which is connected thereto by an adjustable tension link 23 extending through the lugs 18 and 4 4 to 20 19 and through the flange 22. The inside face 24 of the tension r to link head 25 is part conical so as to form a pivot bearing about which the flange 22 may pivot. The heel 26 of the flange 22 engages the adjacent lug 18 while the remote end of the lever 21 passes through a slot 27 in the free end 28 of the actuating link 29 whereby the lever 21 is restrained in its operative attitude with the heel seated against the lug 18. A spring biassed the lugs 18 and 19 away from one another.

The actuating link 29 is pivotally mounted at 31 to the vehicle chassis 32 and a return spring 33 extends from a mounting bracket 34 on the link 29 to a further mounting bracket on the chassis 32. The arrangement is such that downward pivotal movement of the free end 28 pivots the lever 21 and actuates the brake through the tension link 23.

Pivotal movement of the actuating link 29 is effected by an upstanding operating lever 36 extending upwardly from a pivotal mounting 37 on the chassis 32. The lever 36 is formed E: 10 with a rounded wiper member 38 beneath the pivot mounting 37 which engages slidably with the upper flat surface 40 of the link 29. A stop 41 is struck from the link 29 so as to prevent pivotal movement of the lever 36 beyond an over-centre position corresponding to maximum resultant pivotal movement of the link 15 29.

An eccentric support member 44 is supported beneath the S: lower shoe 12 and is adjustable so as to maintain the shoes in their concentrically arranged position spaced from the drum 14 whereby shoe drag is prevented in the inoperative position.

In use, the lever 36 is held in an inoperative position as shown in FIG. 2 by the return spring 33. The lever 36 may be raised whereupon the wiper member 38 engages the actuating link 29 and pivots it downwardly to actuate the brake. Maximum braking force is achieved when the wiper member 38 is directly between the flat surface 40 and the pivot mounting 37, called the central position. Thus a variable braking force may be achieved by moving the lever 36 from its inoperative position to I I Ih3c2nl 4 4(

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4, 4 4 4 4 4 4 4- 14 4 4t 4 4 4l the central position.

A parking brake is effected by moving the lever 36 beyond the central position to a slightly over-centre position at which the lever 36 is held by the stop 41 by the action of the return spring acting to move the upper surface upwardly so as to clamp the wiper member 38 in the over-centre position. The lever may be readily pivoted forwardly to release the parking brake. The pivotal mounting 37 comprises apertures 42 in the sile flanges 39 which extend down from the upper chassis panel 43 adjacent the underside thereof whereby the upper faces of the shaft which pivots in the apertures 42 is restrained against the underside of the panel 43.

FIG 3 illustrates a further embodiment of the invention in which the actuating link 50 is a tension link supported for reciprocal movement in the chassis 52 and the wiper member 51 is an eccentric member mounted pivotally on the chassis 52. A stop 53 limits pivotal movement of the lever in one direction which coincides substantially with full retraction of the link 51.

The latter supports a follower 54 against which the eccentric 20 member 51 acts.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is defined in the appended claims.

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Claims (5)

1. 4. 949 .9 9 *i 94 1. Actuating means for actuating a brake assembly, the actuating means including:- a brake link member moveable from an inoperative position to actuate said brake assembly, and a manual or foot operable member pivotable for effecting camming engagement between the manual or foot operable member and the brake link member, said camming engagement causing operative movement of said brake link member. 2. Actuating means as claimed in claim 1, wherein said brake link member is pivotally moveable for actuating said brake assembly and said camming engagement results in operative pivotal movement of said brake link member. 3. Actuating means as claimed in claim 1 or claim 2, wherein said camming engagement is associated with an over-centre mechanism. 4. Actuating means as claimed in claim 3, wherein substantially maximum resultant movement of said brake link member from its inoperative position occurs when said manual or foot operable member is in an over-centre position and stop means are provided to limit pivotal movement of said manual or foot operable member. lr r *r rr L i Iil L (LII IL I I ii~s i: -mr 8 An external contracting brake assembly including:- a rotary member to be braked; a pair of opposed braking shoes pivotally connected together about a fix3d pivot assembly for pivotal movement between an engaged attitude engaged with said rotary member and disengaged attitude operatively spaced from said rotary member; supporting members on each said shoe remote from said fixed pivot assembly and arranged in spaced apart relationship whereby they may be moved together to pivot said braking shoes to said engaged attitude; St a linkage assembly linking said supporting members whereby they may be moved together to pivot said braking shoes to said If engaged attitude, said linkage assembly including a linkage link member, and being operable for moving said braking shoes to said engaged attitude V actuating means for actuating said linkage link member, said actuating means being substantially as claimed in any one ieV... of the preceding claims.
2. 6. An external contracting brake assembly as claimed in claim wherein said linkage assembly includes a manual actuating lever extending across a face of one supporting member remote from the other supporting member and having an abutment engageable with said face, and connecting means connecting said other supporting member to said lever at a position spaced from said abutment whereby said lever may be pivoted about said abutment to an applied a illx pl"f;nZR 9 position at which said braking shoes are disposed in said engaged attitude.
3. 7. An external contracting brake assembly as claimed in claim 6, wherein said lever extends into a slot within said brake link member to form a pivotal connection thereto.
4. 8. An external contracting brake assembly as claimed in claim 7, wherein the extension of said lever into said brake link member maintains operative alignment between said lever and said supporting members.
5. 9. A brake assembly substantially as hereinbefore described with reference to the accompanying drawings. Ir a. Ca a sac. sea Lic I DATED THIS Twentieth DAY OF May 1994. BARTLEM PTY LTD by PIZZEY COMPANY PATENT ATTORNEYS A*: f t t v>T