Brakes – Vehicle
Reexamination Certificate
2001-07-17
2002-08-20
Butler, Douglas C. (Department: 3683)
Brakes
Vehicle
C074S502600, C188S10600P
Reexamination Certificate
active
06435317
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a brake-actuating mechanism for use on a drum brake device, designed to mechanically move a pair of brake shoes away from each other in response to operation of an operating lever. More particularly, it relates to a brake cable-connecting apparatus designed to permit a brake cable to remain connected on the operating lever, even during transportation of the drum brake device.
DESCRIPTION OF THE RELATED ART
One known type of a prior art brake cable-connecting apparatus of a brake-actuating mechanism as described above is illustrated in
FIGS. 14
a
and
14
b
, disclosed in Japanese Patent Application Laid-Open No. 2000-108855.
In
FIGS. 14
a
and
14
b
, a strut, an operating lever and a brake cable are identified by reference numerals
1
,
2
and
3
, respectively. As described below, these components comprise a drum brake-actuating mechanism in cooperation.
A brake shoe engagement groove
1
a
is formed at one end of the strut
1
, with which one brake shoe (not shown) is engaged. The operating lever
2
is pivotably supported on the strut
1
in a state in which a proximal end of the lever
2
is pivoted about the other end of the strut
1
by means of a pivot pin
4
. A brake shoe engagement groove
2
a
is formed at the proximal end of the operating lever
2
, with which the other brake shoe (not shown) is engaged.
As illustrated in
FIG. 14
b
, a cable end engagement recess
2
b
is formed at a free end of the lever
2
, with which a cable end
3
a
of the brake cable
3
is engaged in a brake cable pulling direction, or rather in a cable operating direction.
In the above structure, when a cable-pulling force indicated by arrow “W” is actuated on the operating lever
2
via the brake cable
3
, then the operating lever
2
rotates about the pin
4
in a corresponding direction, thereby thrusting the corresponding brake shoe in a leftward direction of
FIG. 14
b.
Such rotational movement of the lever
2
imparts a counterforce to the strut
1
, thereby pushing the strut
1
together with the corresponding brake shoe in a rightward direction of
FIG. 14
b.
The action of the brake shoes away from each other causes the brake shoes to be pressed against an inner circumferential surface of a brake drum (not shown), thereby providing a predetermined braking action.
In order to engage the cable end
3
a
with the cable end engagement recess
2
b
at the free end of the lever
2
, the brake cable
3
(cable end
3
a
) is initially inserted into the brake-actuating mechanism as shown by arrows in
FIG. 14
a
, and then the cable end
3
a
is positioned above the cable end engagement recess
2
b
. The brake cable
3
is pulled in the operating direction as shown by arrows in
FIG. 14
b
, thereby engaging the cable end
3
a
with the cable end engagement recess
2
b.
The drum brake device is sometimes transported in a state that the brake cable
3
(the cable end
3
a
) is installed to the operating lever
2
. In this case, easy disengagement of the brake cable
3
(the cable end
3
a
) from the operating lever
2
significantly reduces operability.
As disclosed in the above-described prior art, conventional practice to prevent such disengagement is that the width of an opening of the cable end engagement recess
2
b
is made smaller than a diameter of the cable end
3
a
so that a great pulling force must be actuated on the brake cable
3
at the final step as shown by the arrow in
FIG. 14
b
in order to insert the cable end
3
a
into the brake cable engagement recess
2
b
. Such a proposal has been made to provide a countermeasure to avoid disengaging the brake cable
3
(the cable end
3
a
) from the operating lever
2
during transportation of the drum brake device.
However, such a conventional countermeasure impairs operability because the cable end
3
a
must be inserted into the brake cable engagement recess
2
b
with the great force. This means that cable-connecting operability is sacrificed for engagement of the cable end with the brake cable engagement recess
2
b
, and this is an impractical method.
Since the end
3
a
is forcedly inserted into the brake cable engagement recess
2
b
by the great force, the end
3
a
and the opening of the brake cable engagement recess
2
b
may be damaged or deformed. This is an impractical method as well.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, an object of the invention is to obviate the above problem by means of another countermeasure that substantially differs in idea from the above-described prior art, and further to provide an improved brake cable-connecting apparatus designed to engage a cable end of the brake cable in positive engagement with a cable end engagement recess of an operating lever at a free end thereof, with little increase in effort required for engaging the cable end with the cable end engagement recess, without a sacrifice of cable-connecting operability, and without damage or deformation of the cable end and the opening of cable end engagement recess.
In order to accomplish this object, in the first aspect, a brake cable-connecting apparatus of a brake-actuating mechanism for use on a drum brake, the brake actuating mechanism comprises: a strut engaging with one of a pair of brake shoes at one end thereof; an operating lever, being pivotably attached to the strut at the other end of the strut, engaging with the other of the brake shoes at the other end thereof; a brake cable, a cable end thereof engaging with a free end of the operating lever in a cable operating direction so as to rotate the operating lever relative to the strut with a pivotal attachment portion by applying a brake cable-pulling force on the free end of the operating lever, thereby moving the brake shoes in a direction away from each other. Notably, a resilient member is extending into a path in which the cable end moves when the cable end engages with the free end of the operating lever and is positioned to interfere with the cable end so that the cable end can pass over the resilient member with sufficiently resiliently. The resilient member is deformed by the cable end when the cable end moves in the path in the cable operating direction, while the cable end can not pass over the resilient member when the cable end moves in the path in a cable releasing direction substantially opposite to said cable operating direction.
When the brake cable-pulling force is imposed on the free end of the operating lever via the cable end, then the operating lever and strut are relatively pivoted with respect to each other about the pivotal attachment portion, thereby moving the brake shoes away from each other. In engaging the cable end with the fee end of the operating lever, a brake cable is pulled by light force, and the cable end is thereby held against the free end of the operating lever.
According to the first aspect of the invention, the use of the resilient member makes it feasible to engage the cable end in positive engagement with a cable end engagement portion of the operating lever at the free end thereof, with little increase in effort required for holding the cable end in engagement with the free end of the operating lever, without a sacrifice of cable-connecting operability, and without damage or deformation of the cable end and the cable end engagement portion.
According to a second aspect of the present invention, an object of the invention is to provide an improved brake cable-connecting apparatus wherein the operation and effects according to the first aspect of the invention are achievable by means of a low cost countermeasure including a plate spring.
In the second aspect of a brake cable-connecting apparatus as defined in the first aspect of the invention, the resilient member is formed by a plate spring disposed so as to be resiliently deformed in a thickness direction of the plate spring by the cable end when the cable end runs in the path in the operating and releasing directions. For the second aspect, the resilient deformation in the cable
Kurihara Katsuhisa
Tanaka Takao
Butler Douglas C.
Liniak Berenato Longacre & White
Nisshinbo Industries Inc.
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