Machine element or mechanism – Control lever and linkage systems – Hand operated
Reexamination Certificate
2000-03-31
2001-11-20
Green, Mary Ann (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Hand operated
C074S500500, C188S10600P
Reexamination Certificate
active
06318207
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 be mechanically moved these members away from each other through the manipulation of a control lever, and in more detail, a device for detachably connecting a control cable to a free end of the control lever in this device.
2. Description of the Related Art
As to a control cable connecting device for the above mentioned operating device, there has been known, for example, a device as shown in FIGS.
16
(
a
) and
16
(
b
) for detachably connecting a brake cable with a free end of a control lever for operating a drum brake, which is disclosed in U.S. Pat. No. 5,311,793.
Referring to FIGS.
16
(
a
) and
16
(
b
), there are shown a pair of brake shoes
1
,
2
as members to be operated, a pressing bracket
3
, a control lever
4
, and a brake cable
5
as a control cable, which are correlated with one another as explained as follows, so as to constitute an operating device
6
for a drum brake.
The pressing 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 pressing bracket
3
is provided at the other end with the control lever
4
pivotally journalled at its proximal end by means of a pivot pin
7
, while the control lever
4
is formed at the proximal end with a cut-out
4
a
to which the other brake shoe
2
is engaged.
The operating 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 control lever
4
through the brake cable
5
, in the direction indicated by the arrow W, the control lever
4
is rotated around the pivot pin
7
in the corresponding direction to push the brake shoe
2
leftward in the figure.
Meanwhile, the above mentioned rotation of the control lever
4
around the pivot pin
7
applies a reaction force to the pressing bracket
3
through the intermediary of the pivot pin
7
, and accordingly, the pressing bracket
3
is pushed rightward in the figure together with the brake shoe
1
.
The brake shoes
1
,
2
, as a result of the above mentioned operation of moving away from each other thereof, are pressed against the inner peripheral surface of a brake drum which is not shown, and accordingly, a braking operation can be carried out.
By the way, 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 control lever
4
while the drum brakes are incorporated in a use condition, and accordingly, the operating device
6
is further incorporated therein additionally with the following arrangement.
That is, as clearly shown in FIG.
16
(
b
), the pressing bracket
3
is bifurcated, 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 leg parts
3
b
,
3
c
and an inner end wall
3
d
, in which space the control lever
4
is accommodated.
Further, the control lever
4
is also bifurcated, except the proximal end in which the pivot pin
7
and the cut-out
4
a
exist, so as to define a space between a pair of opposed leg parts
4
c
,
4
d
, though which space the brake cable
5
can pass.
However, the distance between the pair of opposed leg parts
4
c
,
4
d
is selected such that the end fitting
5
a
of the brake cable
5
cannot pass through the space between the opposed leg parts
4
c
,
4
d
, and the opposed leg parts
4
c
,
4
d
are formed respectively with the above mentioned cut-outs
4
b
for engaging the end fitting
5
a
of the control cable
5
.
As clearly shown in FIG.
16
(
a
), the distance between the free end face of the control lever
4
and the inner end wall
3
d
of the pressing bracket
3
is set to be such a size that the end fitting
5
a
of the control cable
5
can pass through a gap between the free end face of the control lever
4
and the inner end wall
3
d
of the pressing bracket
3
, and a V-shaped leaf spring
8
is interposed so as to block the above gap, one leg part
8
a
of which V-shaped leaf spring
8
being made into close contact with the inner end wall
3
d.
The other leg part
8
b
of the V-shaped leaf spring
8
is made into close contact with the free end face of the control lever
4
to define a wedge-like space
9
between the leg part
8
b
of the V-shaped leaf spring
8
and the free end face of the control lever
4
, which wedge-like space
9
guides the end fitting
5
a
of the brake cable
5
upon insertion which will be explained hereinafter.
When the brake cable
5
is to be engaged the free end of the control lever
4
, the end fitting
5
a
of the brake cable
5
, as indicated by the two-dot chain line in FIG.
16
(
a
), is at first inserted into the above mentioned wedge-like space
9
from the outside of the drum brake, and then, the brake cable
5
and its end fitting
5
a
are pushed further as indicated by the arrow &agr;.
At this time, the end fitting
5
a
is further advanced while being supported against the free end face of the control lever
4
and elastically deforming the sprig leg part
8
b
of the V-shaped leaf spring
8
in a direction indicated by the arrow &bgr;. When the end fitting
5
a
overrides the free end face of the control lever
4
, the end fitting
5
a
is pushed by elastic restoration of the spring leg part
8
b
in a direction reverse to the direction indicated by the arrow &bgr; so that the end fitting
5
a
is engaged with the cut-outs
4
b.
It is noted that this elastic restoration of the spring leg part
8
b
can prevent the end fitting
5
a
of the brake cable
5
from disengaging from the free end of the control lever
4
.
When the brake cable
5
is to be removed, the spring leg part
8
b
of the V-shaped leaf spring
8
is elastically deformed in the direction indicated by the arrow &bgr; from the outside of the drum brake with use of a suitable tool, and in this condition, in reverse order of the above mentioned steps, the end fitting
5
a
of the brake cable
5
is disengaged from the cut-outs
4
b
, and then the brake cable
5
is pulled out of the drum brake with its end fitting
5
a.
By the way, 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 is allowed to pass through the gap between the free end face of the control lever
4
and the inner end wall
3
d
of the pressing bracket
3
so as to engage or disengage the brake cable
5
, 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
of the brake cable
5
from disengaging from the free end of the control lever
4
, the gap between the free end face of the control lever
4
and the inner end wall
3
d
of the pressing bracket
3
, as indicated by A in FIG.
16
(
a
), should be set to a size which is obtained by adding gap required for passing of the end fitting
5
a
to 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, there has been a problem such that additional components including the V-shaped leaf spring
8
should be incorporated to be economically disadvantageous.
Furthermore, the brake cable
5
is likely to buckle when the brake cable
5
is pushed into the wedge-like space
9
for engaging the end fitting
5
a
of the brake cable
5
to the free end of the control lever
4
, and accordingly, since careful working is required in order to prevent occurrence of this buckling, and further, since it is required to elastically deform the spring leg part
8
b
of the V-shaped leaf spring
8
when the end fitting
5
a
of the brake cable
5
is detached from the free end of the control leve
Asai Seiji
Ikeda Takashi
Green Mary Ann
Nisshinbo Industries Inc.
Young & Thompson
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