Brakes – Vehicle
Reexamination Certificate
2001-05-18
2003-11-25
Lavinder, Jack (Department: 3683)
Brakes
Vehicle
C188S10600P
Reexamination Certificate
active
06651782
ABSTRACT:
FIELD OF INVENTION
This invention relates to a drum brake, such as a parking brake, that is operated by a brake cable; more specifically, it relates to a brake cable connecting apparatus for connecting a brake cable to a brake lever provided in the drum brake.
DESCRIPTION OF PRIOR ART
As a conventional brake cable connecting apparatus for a drum brake, a forward-pull type parking brake apparatus is well-known in the art and consists of a brake lever pivotally supported on a shoe web of a brake shoe at a base portion thereof and a brake cable connected on a free end of the brake lever.
One type of brake cable, for remotely pulling and operating the brake lever, mainly consists of an inner cable, a cable end fixed on a tip end of the inner cable and an outer casing. There is the other type of brake cable without the outer casing, in case of either type of brake cable whether the outer casing is included or not, the term “cable” is designated to the part that corresponds to the inner cable in the present specification.
An U-shaped cable-receiving groove is formed at a free end of the brake lever. One end of the cable is connected to a brake operating means such as a hand brake lever in the cabin, and the other or a tip end of the cable penetrates through a back plate and is received in the cable-receiving groove, the cable end securely fixed on the tip end of the cable is engaging with an end edge of the cable receiving groove on the side of a cable releasing direction, thereby preventing the cable from coming off from the cable receiving groove. Actuating the brake operating means such as the hand brake lever for remotely pulling the cable causes the brake lever into rotation and urges the brake shoes to separate apart from each other to effect the parking braking.
Before fixing the brake onto the vehicle, this type of drum brake with the pre-assembled cable causes a drawback by increasing the required stock and transportation space and leaves a potential problem of unexpected damage to the cable during stocking and transportation. Therefore it is preferable that the cable does not connect to the drum brake in the process of drum brake assembly sub-step but in the process of vehicle assembly step.
One idea of a brake cable connecting apparatus, displaying a function of inserting a cable from outside into a drum brake and precisely receiving that cable in a brake cable-receiving groove and further snapping a cable end automatically on an edge surface of the groove at the side of the cable releasing direction, is disclosed in U.S. Pat. No. 5,002,159.
However, the above-described prior art of the brake cable connecting apparatus presents the possibility that the cable end happens to be disengaged from the brake lever if the cable slacks or returns to the initial position earlier than the brake lever when the parking brake is released. As such, an improved brake cable connecting apparatus to overcome such a problem is disclosed as an example shown in FIGS. 16-18 of WO98/40640 Patent Application.
FIG. 16
is a plan view of a leading-trading type (LT type) drum brake (drum brake assembly);
FIG. 17
is an enlarged view of a connecting area of a brake cable when seen from arrow A in
FIG. 16
; and
FIG. 18
is a partially enlarged plan view of a connecting area of the brake cable illustrating in FIG.
16
.
A pair of brake shoes
1
,
2
, having an identically structure, are symmetrically disposed on the right and left in FIG.
16
and comprised of the following elements: semicircular shoe webs
1
a
,
2
a
; shoe rims
1
b
,
2
b
secured to form a T-shape in cross section; and, linings
1
c
,
2
c
fixed on a circumferential surface of the shoe rims
1
b
,
2
b
, respectively. With shoe holding mechanisms
3
,
4
, the brake shoes
1
,
2
are resiliently mounted on a back plate
11
, only a center hole and an opening
11
a
are shown in the figure with a one dash chain line and a broken line, and lower adjacent ends thereof abut on and engage with an anchor member and are restricted from lifting by a retaining plate
5
.
Upper adjacent ends of the brake shoes
1
,
2
operationally engage with a pair of left and right pistons of a wheel cylinder
6
, respectively. An upper return spring
8
and a lower return spring
9
are stretched between a pair of brake shoes
1
,
2
to urge the brake shoes
1
,
2
in the retract direction. A brake lever
20
is superposed on the shoe web
1
a
of one brake shoe
1
and a base portion thereof is pivotally supported on the shoe web
1
a
with a pin
10
. The brake lever
20
is able to rotate with the pin
10
from a position illustrated by a solid line to a position
20
′ illustrated by a one-dash chain line in a clockwise direction. A strut
7
provided between the pair of brake shoes
1
,
2
restrict return positions of the brake shoes
1
,
2
with actions of both return springs
8
,
9
by abutting one end thereof on the brake lever
20
provided on one brake shoe
1
and the other end thereof on the other brake shoe
2
.
A tongue like piece
20
b
, formed on the brake lever
20
by partial-shearing, functions as a stopper by abutting on an edged surface closer to the brake center of the shoe web
1
a.
An opening
11
a
is pierced at the lower left side of the back plate
11
in
FIG. 16
, and a short conducting pipe
11
b
is fixed to the opening
11
a.
A coil spring
31
is compressed from an end of the conducting pipe
11
b
in the brake to a U-shaped cable end insertion groove
20
a
formed at a free end of the brake lever
20
by bending. The coil spring
31
urges the brake lever
20
into an initial position illustrated as a solid line and functions as a biasing means to orient the cable end
42
toward the cable end insertion groove
20
a
upon connecting the brake cable
40
to the brake lever
20
.
As shown in
FIG. 17
, openings
20
c
is pierced on both side walls of the cable end insertion groove
20
a
of the brake lever
20
and one end of an L-shaped flap
33
is rotationally attached around a shaft
32
fit into both openings
20
c.
A clockwise rotation of the flap
33
is restricted by abutting a free end thereof against a backward surface (at the side of a cable releasing direction) of the cable end insertion groove
20
a
as illustrated by a solid line in
FIG. 18
, while counterclockwise rotation thereof is permitted. A torsion spring
34
wound on the shaft
32
acts on the flap
33
toward the position illustrated as a solid line in
FIG. 18
; therefore the flap
33
usually covers the cable end insertion groove
20
a
. Consequently, the flap
33
is only rotated when an external force is added to the flap
33
against the application force of the torsion spring
34
. A cable insertion recess
33
a
is formed at the tip end of the free end of the flap
33
.
The brake cable
40
consisted of a cable
41
and a cable end
42
securely fixed to an end of the cable
41
. The cable end
42
has a larger diameter than that of the cable
41
and is a bullet-shape at the tip end. The brake cable connecting procedure of the brake cable
40
onto the brake lever
20
will be explained bellow.
The cable end
42
of the brake cable
40
, inserted into the opening
11
a,
passes through the conducting pipe
11
=i a =l and reaches the cable end insertion groove
20
a
while being conducted along by the coil spring
31
. Furthermore, the cable end
42
advances inside the cable end insertion groove
20
a
and pushes the free end of the flap
33
, which then is made to rotate and lift the flap
33
in the counterclockwise direction. If the flap
33
rotates to a position
33
′ illustrated as a broken line in
FIG. 18
, the tip end of the flap
33
falls down along a stepped surface
42
a
of the cable end
42
at a behind end by the resilient force of the torsion spring
34
, thereby retracting to the initial position shown the solid line. At the same time, the small stem at the backward half of the cable end
42
is sandwiched between the cable insertion recess
33
a
of the flap
33
and the bottom of the cable end
Asai Seiji
Ohnishi Junichi
Apex Juris pllc
Heims Tracy M.
Lavinder Jack
Nisshinbo Industries Inc.
Pezzlo Benjamin A
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