Brakes – Elements – Brake wheels
Reexamination Certificate
2000-10-10
2003-01-07
Lavinder, Jack (Department: 3683)
Brakes
Elements
Brake wheels
C188S072400, C188S071100
Reexamination Certificate
active
06502673
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a cylinder device for a disc brake as defined in the preamble portion of claim
1
and more specifically relates to an improvement in the assembly of a dust boot.
DESCRIPTION OF THE RELATED ART
One example of a traditional disc brake device is disclosed in FIG.
9
. This prior art comprises: a carrier
600
to be fixed on a stationary portion of a vehicle; a caliper
200
configured with an inboard actuating portion
210
, an outer reaction leg
220
facing the actuating portion, and a bridge
230
extending between the actuating portion
210
and the reaction leg
220
; a piston
300
slidably fit into a cylinder bore
211
formed in the actuating portion
210
of the caliper
200
; an inner pad
100
urged to be pressed by the piston
300
and frictionally engaged with one side surface of a disc rotor D; an outer pad
110
urged to be pressed by the reaction leg
220
and frictionally engaged with the other side surface of the disc rotor D; and a dust boot
400
designed so that an intermediate flexible portion
430
thereof is received in a large diameter bore
213
stepped up from the cylinder bore
211
and surrounded by a peripheral portion
214
defining the large diameter bore
213
. Thick ring portions
410
,
420
of the dust boot
400
are fit respectively into an outer circumferential groove formed on the peripheral surface of the piston
300
and into an inner circumferential groove
212
formed on the inner circumferential surface located adjacent to the open end of the cylinder bore
211
.
This type of disc brake device is configured to perform a braking action by use of a pair of pads
100
,
110
to sandwich and press both sides of the disc rotor D in the axial direction. The dust boot
400
is designed to protect the slidable portion of the piston
300
in the cylinder bore
211
from intrusion of foreign matter.
A process of installing the piston
300
and the dust boot
400
in the caliper
200
is explained with reference to FIGS.
10
(A)-(D).
As shown in FIG.
10
(A), one thick ring portion
410
of the dust boot
400
is elastically connected with the periphery of the cup-like piston
300
at its bottom side. As shown in FIG.
10
(B), the piston
300
with the dust boot
400
is to be held, by one hand, within the space defined by the actuating portion
210
, the bridge
230
and the reaction leg
220
so that the bottom of the piston
300
faces the actuating portion
210
. As shown in FIG.
10
(C), the other thick ring portion
420
of the dust boot
400
is fit, by the other hand, into the inner circumferential groove
212
adjacent to the open end of the cylinder bore
211
. As shown in FIG.
10
(D), as the piston
300
is being forced into the cylinder bore
211
, the one thick ring portion
410
is fit into the outer circumferential groove
310
on the peripheral surface of the piston
300
.
The above-described conventional art has the following points to be improved.
In the conventional device, the installation of the dust boot
400
is manually performed, which makes the installation complex and requires considerable time. That is, in the process shown in FIG.
10
(C), when the other thick ring portion
420
of the dust boot
400
is to be fit into the inner circumferential groove
212
which is positioned within the cylinder bore
211
, the peripheral portion becomes an obstacle for fingers to be inserted, which specifically causes a problem in fitting the other thick ring portion
420
into the inner circumferential groove
212
.
Because of the difficulty in installing the dust boot
400
, it is possible that the piston
300
is forced into the cylinder bore
211
with the dust boot
400
not being installed properly, which may cause a damage to the dust boot
400
.
The peripheral portion functions to protect the dust boot
400
against flying gravel during operation in a vehicle and to increase the strength of the connecting section between the actuating portion
210
and the bridge
230
of the caliper
200
. However, the peripheral portion at the brake center side has no effect on the strength increase. In this respect, its portion is wasteful, thereby increasing the weight of the device.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of this invention to provide a cylinder device for a disc brake device, which facilitates the installation work of the dust boot
400
into the inner circumferential groove
212
of the cylinder bore
211
and removes the wasteful portion of the peripheral portion
214
, thereby eliminating the problems such as a weight increase and reducing the weight of the caliper device.
This invention is based on the finding that the peripheral portion
214
at the brake center side has no effect with respect to the strength increase and has an effect for protecting the dust boot
400
against flying gravel during operation in a vehicle but mainly increases the weight of the device.
To this end the present invention provides a cylinder device as defined in claim 1. Preferred embodiments of the invention are defined in the sub-claims.
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Lavinder Jack
Liniak Berenato & White
Nisshinbo Industries Inc.
Pezzlo Benjamin A
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