GB2244022A

GB2244022A - Caliper piston pressing in tool; prizing

Info

Publication number: GB2244022A
Application number: GB9011170A
Authority: GB
Inventors: John Hubber
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-05-18
Filing date: 1990-05-18
Publication date: 1991-11-20
Also published as: GB9011170D0

Abstract

A caliper piston re-alignment tool 15 is inserted into space 33 between disc 23 and a caliper piston 28 which has been vacated by a worn disc brake pad or in conjunction with a spacing block into space between the caliper pistons or into space between a caliper piston and a caliper lug which have lifted clear of the worn disc brake pads. By squeezing a shaped handle 16 to a shaped handle 12 of tool 15 the caliper pistons are pressed into their respective sockets 28 so that new disc brake pads may be fitted into the enlarged space. The tool 15 comprises a caliper piston bearing plate 11 and a disc bearing lever 18 connected to arms 34 and 35 which are connected together by and swivel around pin or ratchet 17 with the other ends of the shaped handles 12, 16 tapered at 14. A spring 13 attached to the shaped handles will re-align the caliper piston bearing plate 11 and the disc bearing lever 18 ready for re-use. The bearing plates and bearing levers may be differently shaped (figures 2, 3 not shown). <IMAGE>

Description

CALIPER PISTON RE-ALIGNMENT TOOL This invention relates to a caliper piston re-alignment tool.

Disc brakes on a motor vehicle is a well known form of braking system. To each wheel that has been fitted with disc brakes there is a caliper which bridges the disc within its legs with one or two or four caliper pistons in contact with two disc brake pads which will squeeze the disc between them.

The driver of a moving motor vehicle wishing to slow down operates the braking system by depressing the brake pedal and by a system of hydraulics the force is transferred to the caliper pistons and thus to the disc brake pads, which are situated either side of the disc, the friction of the disc brake pads on the disc will slow the rotating disc which will slow the motor vehicle. With the repeated uses of the braking system the disc brake pads are gradually worn away, the caliper pistons automatically compensating for the wear of the disc brake pads. Eventually the disc brake pads will require changing.

The reduced gap between the disc and the caliper piston when the worn disc brake pad has been removed is very narrow and to find the recommended piece of wood or metal bar to force the caliper piston against the resistance inherent in the hydraulics system back into its original position to allow the much thicker new disc brake pad to be fitted is invariably the wrong size or can cause damage to the caliper piston or caliper piston seal which would be expensive to repair.

According to the present invention there is provided a caliper piston bearing plate connected to an arm and a shaped handle, a disc bearing lever connected to an arm and a shaped handle with a ratchet or pin which connected the two arms together around which the two swivel, the shaped handles are tapered at one end and a spring which is attached to the shaped handles together with a spacing block.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings: Figure 1 shows in perspective, the caliper piston re-alignment tool.

Figure 2 shows an alternative caliper piston bearing plate and disc bearing lever.

Figure 3 shows another alternative caliper piston bearing plate and disc bearing lever.

Figure 4 illustrates the caliper piston re-alignment tool with the caliper piston bearing plate and the disc bearing lever in the open position.

Figure 5 shows the general arrangement of one type of caliper comprising disc brake pads, caliper pistons, disc, caliper piston seals and the disc brake pad retaining pins.

Figure 6 illustrates the reduced space between the disc and the caliper pistons.

Figure 7 illustrates how the caliper piston re-alignment tool operates in conjunction with the disc and the caliper piston.

Figure 8 shows the general arrangement of a second type of caliper comprising caliper, caliper pistons disc brake pads, disc, caliper piston seals and caliper retaining pins.

Figure 9 shows the general arrangement of a third type of caliper comprising caliper, caliper piston, disc brake pads, disc, caliper piston seal and caliper retaining pins.

Figure 10 illustrates the caliper piston re-alignment tool in conjunction with the spacing block and a type of caliper.

Figure 11 illustrates the caliper piston re-alignment tool in conjunction with the spacing block and another type of caliper.

Figure 12 illustrates the component parts of the spacing block.

Figure 13 illustrates how the component parts are used to fill the variable space between the caliper piston and the caliper lug.

Referring to the drawings the caliper piston re-alignment tool 15 comprises a caliper piston bearing plate 11 or 20 or 21 connected to an arm 34 and a shaped handle 12, a disc bearing lever 18 or 19 or 22 connected to an arm 35 and a shaped handle 16, a pin or ratchet 17 connects arms 34 and 35 together, a spring 13 can also be connected to the handles 12 and 16 which can be tapered 14 at one end and a spacing block 41.

The motor vehicle, not shown, whose disc brake pads require changing is jacked up so that the road wheels, not shown, can be removed, the cap of the master cylinder of the brakes hydraulics system, not shown, is removed.

Referring to Figure 5 the disc brake pad pins 24 are removed from the caliper 27 and one of the worn disc brake pads 25 is removed via aperture 36, the caliper piston re-alignment tool 15 is placed into the space 33 between disc 23 and the caliper piston 29 or 30, by squeezing handle 16 to handle 12 which pivots around pin or ratchet 17, compressing spring 13, arms 34 and 35 swivel in opposite directions, the disc bearing lever 18 or 19 or 22 is in contact with disc 23 and the caliper piston bearing plate 11 or 20 or 21 is kept squarely onto caliper piston 32 or 26 which is pressed into the caliper piston socket 28 or 30, without damage to the disc 23 or caliper piston 32 or 26, which is pressed into the caliper piston socket 28 or 30 square and true.The caliper piston seal 31 or 26 one end of which is set into a groove, not shown, in the caliper piston 29 or 32, will follow the movement of the caliper piston 29 or 32 without damage. The caliper piston re-alignment tool 15 is removed and the new disc brake pad, not shown, is placed into the enlarged space 33, the second worn disc brake pad 25 is removed and the above described steps are repeated. The spring 13 will re-align the caliper piston bearing plate 11 or 20 or 21 and the disc bearing lever 18 or 19 or 21 in readiness for re-use.Where both worn disc brake pads 25 are removed at the same time and the caliper piston realignment tool 15 is used as previously described, caliper piston 32 will be pressed into caliper piston socket 28 caliper piston 29 will extend from caliper 27 to disc 23, after inserting a new disc brake pad, not shown, into enlarged space 33 between disc 23 and caliper piston 32 and by turning caliper piston re-alignment tool 15 and inserting tapered ends 14 into the reduced space 33 the caliper piston 29 will be moved sufficiently to allow the caliper piston re-alignment tool 15 to be used as previously described.

Referring to Figures 8 and 9 the caliper securing pins 42 are removed and caliper 37 or 39 are lifted clear of the worn disc brake pads 25 and by inserting the caliper piston re-alignment tool 15 in conjunction with spacing block 41 into space 44 between caliper pistons 29 and 32 or into space 43 between caliper lug 37 and caliper piston 29 and then using caliper piston re-alignment tool 15 as previously described to force the caliper pistons 32 or 29 into caliper piston socket 30 and or 28.

To overcome to variable distances between caliper pistons 32 and 25 in Figure 8 and also between caliper piston 29 and caliper lug 37 in Figure 9 spacing block 41 components 45 and 46 are moved in opposite directions along tongue 51 and groove 52 to increase the overall depth and releasably secured with winged screw 50 then spacing block 41 can be attached to the caliper piston re-alignment tool 15 by the use of an elastic band 49 along groove 48 and securing grooves 47 in the disc bearing lever 18 or 19 or 22 caliper piston bearing plate 11 or 20 or 21.

Refitting the disc brake pad pins 24 or the caliper securing pins 42, refitting the road wheels, not shown, and refitting the cap to the master cylinder of the hydraulic braking system and applying the footbrake, not shown, hard several times to bring the new disc brake pads, not shown, into contact with the disc 23.

Claims

1 A caliper piston re-alignment tool comprising a caliper piston bearing plate connected to an arm and a shaped handle, a disc bearing lever connected to an arm and a shaped handle, a pin or ratchet connecting the two arms which also acts as a swivel, a spring is connected to the handles the ends of which are tapered and when inserting into position and the handles squeezed together the caliper piston will return into the caliper piston socket.

2 A caliper piston re-alignment tool as claimed in Claim 1 wherein the caliper piston bearing plate and the disc bearing lever end of the caliper piston re-alignment tool will fit into the space vacated by the worn disc brake pad.

3 A caliper piston re-alignment tool as claimed in Claim 1 and Claim 2 wherein the caliper piston will be pressed square and true into the caliper piston socket.

4 A caliper piston re-alignment tool as claimed in Claim 2 and Claim 3 wherein the tapered ends of the handles will move caliper piston sufficiently to allow the caliper piston bearing plate and the disc bearing lever end of the caliper piston re-alignment tool to be inserted.

5 A caliper piston re-alignment tool as claimed in Claim 4 wherein the spring will re-align the caliper piston bearing plate and the disc bearing lever ready for re-use.

6 A caliper piston re-alignment tool as claimed in any preceeding claims wherein there will be no damage to the disc as a result of using the caliper piston re-alignment tool.

7 A caliper piston re-alignment tool as claimed in Claim 6, wherein there will be no damage to the caliper piston as a result of using the caliper piston re-alignment tool.

8 A caliper piston re-alignment tool as claimed in Claim 7, wherein there will be no damage to the caliper piston seal as a result of using the caliper piston re-alignment tool.

9 A caliper piston re-alignment tool as claimed in Claim 8, wherein used in conjunction with the spacing block the caliper pistons will be reset into the caliper piston socket of those types of caliper given in this example.

10 A caliper piston re-alignment tool substantially as described herein with reference to Figures 1 - 13 of the accompanying drawings.