AU618968B2

AU618968B2 - Anti-rattle spring

Info

Publication number: AU618968B2
Application number: AU24784/88A
Authority: AU
Inventors: John Nemanic
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-11-06
Filing date: 1988-11-07
Publication date: 1992-01-16
Anticipated expiration: 2008-11-07
Also published as: AU2478488A

Description

S F Ref: 42680 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATiOI 'I

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(ORIGINAL)

FOR OFFICE USE: Class Int. Class Application Number: PI5286 Lodged: 6 November 1987 Accepted: Published: Priority: Related Art: Nane and Address of Applicant: Actual Inventor: Address for Service: John Nemanic 82 Hopetoun Avenue Vaucluse New South Wales 2030

AUSTRALIA

John Nemanic Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower, 31 Market Street, Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: Anti-Rattle Spring The following statement is a full description of this invention, including the best method of performing it known to me/us S00 439 07/ I 1/88 5815/3 I ~11~ The present invention relates to friction pad assemblies for use in a disc brake and, in particular, to anti-rattle springs used in reiation thereto.

Anti-rattle springs on certain types of friction pad assembly are known. For example Fig. 1 shows an anti-rattle spring assembly used in conjuction with a friction pad assembly as disclosed in Australian patent 503263 to Girling Limited. These springs are used to apply gentle pressure to the friction pad continuously so that when the pad is not engaged with the disc of the disc brake it will not rattle.

The anti-rattle spring of Fig. 1 incorporates a coiled centre region g which is threaded upon a stud as shown. A disadvantage of this spring shap.; is that it must actually be threaded uion the stud during assembly of the whole friction pad assembly. In practice this has caused problems when attempting to automate the assembly procedure and currently the chreading p.ocedure is done manually.

Also, in the field, refurbishment of the friction pad assembly typically involves replacement of the friction material and replacement of the anti-rattle spring. With the prior art assembly of Fig. 1 it is necessary to remove the stud in order to fit a new anti-rattle spring. The construction of this prior art anti-rattle spring in practice therefore leads to some time consuming procedures both for the assembly of the new friction pad assembly and for refurbishment thereof in the field.

The disclosure of AU 503263 is incorporated herein by cross-reference.

It is an object of the present invention to provide an improved anti-rattle sprin; for use in conjuction with a friction pad assembly for disc brakes which will substantially overcome, or ameliorate, the above mentioned disadvantages.

In one broad form there is provided a friction pad assembly for use in a disc brake, comprising a backing plate and a pad of friction material RJE/2434Z 2 _II i i secured thereto, a wire spring comprising a central circular partially closed loop, the part of said loop which is not closed comprising a nip region from which two free end regions of the spring extend in generally opposite directions, said spring being attached to the backing plate by the central partially closed region of the spring being engaged over a pin secured to the backing plate.

In a further broad form there is provided an anti-rattle wire spring for a friction pad assembly in use in a disc brake, said anti-rattle wire spring comprising a central circular partially closed loop, the part of said loop which is not closed comprising a nip region from which two spring arms extend in generally opposite directions.

Preferably the far ends of said arms terminate level with thac part of said central region which is opposite said nip region.

Some embodiments of the present inventio)n will now be desc'ibed with reference to the drawings in which:- Fig. 1 is a view of the prior art; Fig, 2 shows a first embodiment of the anti-rattle spring; Fig. 3 shows a second embodiment of the anti-rattle spring; Fig. 4 shows a third embodiment of the anti-rattle spring; Fig. 5 shows the second embodiment of the anti-rattle spring located on a friction pad assembly within a disc brake assembly.

The anti-rattle springs of the present invention as embodied in the embodiments of Figs. 2-4 inclusive show a spring having a central circular loop region which is not fully closed. This form of construction allows the spring to be clipped over a stud of suitable diameter as opposed to being threaded onto the stud. Of course the pvrzent construction of the preferred embodiments also allows the spring to be threaded onto a stud.

Referring particularly to Fig. 2 there is shown an anti-rattle spring 1 comprising a central, approximately three-quarters closed loop 2 and from the open ends 3, 4 of which extend two symmetrical arms 5, 6 _I I Yir having looped ends 7, 8 as shown. The open ends 3, 4 define a nip region 9 as an entry point to the inside of the loop 2. In this embodiment the arms 6 lie parallel to an imaginery- line drawn tangentially to the loop 2 at a point immediately opposite to the nip portion 9.

In a second embodiment, as shown in Fig. 3, the central loop portion remains as in Fig. 2 but the arms 10,11 extending symmetrically from the nip portion 9 are angled upwardly in the direction of the imagine-y tangential line previously referenced. In this embodiment the end looped regions 12,. 13 terminate such that the previously mentioned imaginery tangential line intersects the tops of these loops tangentially as well.

Referring to Fig. 4 the third embodiment is essentially the same as the second embodiment save for the end looped regions 15, 16 being inverted with respect to the looped regions 12, 13 of the second embodiment of Fig. 3.

Each embodiment can be made from spring steel of suitable resilience. In one prefrr'ed form the thickness of the steel used to make the spring is 1.5 mm and is of circular cross-section. In the same preferred form the outside diameter of the central loop is about 10.5 mm, the inside diameter of the central loop is about 7.5 mm, the outside diameter of the outer loops 7, 8, 12, 13, 15, 16 is about 8 mm and the overall width of the spring assembly is about 35.5 mm. The width of the nip is preferably about 4 mm. These dimensions should not be taken as limiting as variations from these dimensions will be necessary to conform with disc brake assemblies for different vehicle models.

In use, as shown in Fig. 5, the spring is located on a pin 20 which pin is affixed to a backing plate 21, the backing plate 21 having mounted thereon friction material adapted to directly engage a brake disc. In practice the backing plate 21 is supported upon portions of the disc brake housing by means of tabs 22, 23. In Fig. 5 these tabs rest upon surfaces R .1 E 2 1 34 4 24, 25 o i- lk l *In use the opposed ends of the anti-rattle spriij 1 are deformed symmetrically downwardly upon insertion into the disc brake housing thereby exerting an upward force on disc brake housing surfaces 26, 27, which force directly results in a downward force of the pad assembly tabs 22, 23 upon their mountings 24, 25 thereby minimizing or preventing any rattle which might occur at the interface between the tabs and their supports, particularly whilst the brake pad is not actually engaged with the brake disc. In manufacture the pin 20 is secured to the backing plate 21, preferably by automated mechanical means. Following this step the spring assembly 1 can be clipped over the pin 20 in a simple, straight forward one movement operation by either manual or automated mear.s. Also, when refurbishing the friction pad assembly typically new friction material is applied to the surface of the backing plate 21 and frequently the antirattle spring is removel for refurbishment and replacement. With the spring of the preferred embodiments there is no need to remove the pin from the backing plate 21 in order to rL,nove Dr replace the spring 1.

Also, manufacture and assembly o" the new friction pad assembly complete with pin and spring can be accomplished using indexing tables with a vibratory hopper. Use of such mechanisms for spring location is much faster and more efficient than air rams and more reliable and efficient than mechanical punches which have typically been required for assembly of the prior art spring assemblies to the friction pad assemblies, The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto without departing from the scope and spirit of the present i r,v ntion.

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Claims

1. A friction pad assembly for use in a disc brake, comprising a backing plate and a pad of friction material secured thereto, a wire spring comprising a central circular partially closed loop, the part of said loop which is not closed comprising a nip region from which two free end regions of the spring extend in generally opposite directions, said spring being attached to the backing plate by the central partially closed region of the spring being engaged over a pin secured to the backing plate.

2. An anti-rattle wire spring for a friction pad assembly in use in a disc brake, said anti-rattle wire spring comprising a central circular partially closed loop, the part of said loop which is not closed comprising a nip region from which two spring arms extend in generally opposite directions.

3. The spring of claim 2 wherein the far ends of said arms terminate level with that part of aid central loop which is opposite said nip region.

4. A friction pad assembly as hereinbefore particularly described incorporating an anti-rattle spring as hereinbefore particularly described with reference to what is shown in Fig. 2. A friction pad assembly as hereinbefore particularly described incorporating an anti-rattle spring as hereinbefore particularly described with reference to what is shown in Fig. 3. 6, A friction pad assembly as hereinbefore particularly described incorporating an anti-rattle spring as hereinbefore particularly described with reference to what is srown in Fig. 4.

7. An anti-rattle spring for a friction pad assembly for use in a disc brake as hereinbefore particularly described with reference to what is shown in Fig. 2.

8. An anti-rattle spring for a friction pad assembly for use in a disc brake as hereinbefore particularly described with reference to what is shown in Fig. 3.

9. An anti-rattle spring for a friction pad assembly for use in a disc brake as hereinbefore particularly described with reference to what is shown in fig. 4. DATED this TENTH day of OCTOBER 1991 John Nemanic f Patent Attorneys for the Applicant SPRUSON FERGUSON