Machine element or mechanism – Control lever and linkage systems – Hand operated
Reexamination Certificate
2000-10-31
2004-04-06
Bucci, David A. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Hand operated
C074S502400
Reexamination Certificate
active
06715378
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for operating a pair of members to be operated, such as brake shoes in a drum brake, so as to mechanically move these members away from each other through the manipulation of a lever, and in more detail, a device for detachably connecting a control cable to the lever.
2. Description of the Related Art
As to a control cable connecting device for the above-mentioned operating device, there has conventionally been known, for example, a device as shown in
FIGS. 10
a
and
10
b
for detachably connecting a brake cable with a lever for operating a drum brake, which is disclosed in U.S. Pat. No. 5,311,793.
Referring to
FIGS. 10
a
and
10
b
, there are shown a pair of brake shoes
1
,
2
as members to be operated, a bracket
3
, a lever
4
, and a brake cable
5
as a control cable, which interact with one another as explained as follows, so as to constitute an operating device
6
for a drum brake.
The bracket
3
is formed at its one end with a cut-out
3
a
to which one of the brake shoes
1
is engaged, and the bracket
3
is provided at the other end with the lever
4
pivotally journalled at its proximal end by means of a pivot pin
7
, while the lever
4
is formed at the proximal end with cut-outs
4
a
to which the other brake shoe
2
is engaged.
The lever
4
is further formed at its free end with cut-outs
4
b
to which an end fitting
5
a
of the brake cable
5
is engaged in a cable pulling direction.
With this arrangement, when a cable pulling force is inputted to the lever
4
through the brake cable
5
, in the direction indicated by the arrow W, the lever
4
is rotated around the pivot pin
7
in the corresponding direction to push the brake shoe
2
outward.
Meanwhile, the rotation of the lever
4
around the pivot pin
7
applies a reaction force to the bracket
3
through the intermediary of the pivot pin
7
, and accordingly, the bracket
3
is also pushed outward together with the brake shoe
1
.
As a result, the brake shoes
1
,
2
are moved away from each other and are pressed against the inner peripheral surface of a brake drum which is not shown, whereby a braking operation can be carried out.
The operating device
6
for a drum brake is preferably constituted in such manner that the brake cable
5
can be engaged with or disengaged from the cut-outs
4
b
of the lever
4
while the drum brake is incorporated in useable condition, and accordingly, the operating device
6
is further incorporated therein additionally with the following arrangement.
That is, as clearly shown in
FIG. 10
a
, the bracket
3
is forked, except the end part where the cut-out
3
a
is formed, so as to have a space which is defined by a pair of opposed legs
3
b
,
3
c
and an inner end wall
3
d
, in which space the lever
4
is accommodated.
Further, the lever
4
is also forked, except the proximal end in which the pivot pin
7
and the cut-outs
4
a
are provided, so as to define a space between a pair of opposed legs
4
c
,
4
d
, though which space the brake cable
5
can pass.
Moreover, the distance between the pair of opposed legs
4
c
,
4
d
is selected such that the end fitting
5
a
of the brake cable
5
cannot pass through the space and the opposed legs
4
c
,
4
d
are formed respectively with the abovementioned cut-outs
4
b
for engaging the end fitting
5
a.
As clearly shown in
FIG. 10
b
, the distance “A” as a gap between the free end face of the lever
4
and the inner end wall
3
d
of the bracket
3
is set to be such a size that the end fitting
5
a
can pass through, and a V-shaped leaf spring
8
is interposed so as to block the above gap, one leg
8
a
of the leaf spring
8
is made into close contact with the inner end wall
3
d.
The other leg
8
b
of the leaf spring
8
is made into close contact with the free end face of the lever
4
to define a convergent tapering space
9
between the other leg
8
b
and the free end face of the lever
4
, which convergent tapering space
9
guides the end fitting
5
a
upon insertion of the latter which will be explained hereinafter.
As to the engagement of the brake cable
5
, the end fitting
5
a
indicated by the two-dot chain line in
FIG. 10
b
is inserted into the space
9
from the outside of the drum brake, and then, the brake cable
5
and its end fitting
5
a
are pushed as indicated by the arrow &agr;.
At this time, the end fitting
5
a
further advances while elastically deforming the spring leg
8
b
in a direction indicated by the arrow &bgr; with using the free end face of the lever
4
as a reaction force receiver. When the end fitting
5
a
overrides the free end face of the lever
4
, the end fitting
5
a
is pushed by elastic restoration of the spring leg
8
b
in a reverse direction against which indicated by the arrow &bgr; so that the end fitting
5
a
is engaged with the cut-outs
4
b.
It should be noted that this elastic restoration of the spring leg
8
b
makes it possible to prevent the end fitting
5
a
from disengaging from the free end of the lever
4
.
Upon detaching the brake cable
5
, the spring leg
8
b
is elastically deformed in the direction indicated by the arrow &bgr; with use of a suitable tool inserted from the outside of the drum brake, and in this condition, in reverse order of the aforementioned steps, the end fitting
5
a
is disengaged from the cut-outs
4
b
, and then the brake cable
5
is pulled out so as to be removed.
In the above-mentioned conventional device for connecting the control cable for the drum brake, since the end fitting
5
a
of the brake cable
5
is allowed to pass through the gap between the free end face of the lever
4
and the inner end wall
3
d
of the bracket
3
so as to carry out engagement or disengagement of the brake cable
5
relative to the free end of the lever
4
, and further, since it is necessary to normally block this gap with the V-shaped leaf spring
8
in order to prevent the end fitting
5
a
from disengaging from the free end of the lever
4
, the gap required for passing the end fitting
5
a
as indicated by “A” in
FIG. 10
b
should be set to a value which is larger than the sum of the diameter of the end fitting
5
a
and the value twice as large as the thickness of the V-shaped leaf spring
8
.
Accordingly, there has been a problem such that the overall length of the operating device
6
becomes longer, and further, in such a case that the overall length of the operating device cannot be increased due to design restriction, since the distance “a” from the center of the pivot pin
7
to the end fitting
5
a
of the brake cable
5
cannot be increased, that is, the lever ratio (a/b) of the lever
4
which is the ratio between the distance “a” and the distance “b” from the center of the pivot pin
7
to the cutouts
4
b
cannot be increased, there is caused such a problem that the brake operating force becomes larger.
Thus, it has not been able to satisfy both requirements of reducing the brake operating force and of shortening the overall length of the operating device
6
.
SUMMARY OF THE INVENTION
An object of a first aspect of the present invention is to provide a device for connecting a control cable, in which an end fitting of the control cable can be inserted into a position between the a journalled portion and the free end of the lever so as to be engaged with or disengaged from the free end of the lever, whereby eliminating above-mentioned problems inherent to conventional operating devices, that is, the problems such that the overall length of the operating device become longer and the brake operating force becomes larger due to the lever ratio of the lever to be ensured, and whereby satisfying both requirements of shortening the overall length of the operating device and of reducing the brake operating force.
To the end, there is provided a device for connecting a control cable for use in an operating device comprising
a strut of which one end is engaged with one of members to be operated,
a lever which is piv
Bucci David A.
Johnson Vicky A.
Nisshinbo Industries Inc.
Young & Thompson
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