Machine element or mechanism – Control lever and linkage systems – Hand operated
Reexamination Certificate
2003-01-17
2003-11-18
Lavinder, Jack (Department: 3683)
Machine element or mechanism
Control lever and linkage systems
Hand operated
C074S489000
Reexamination Certificate
active
06647825
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a hand brake device, more particularly to a hand brake device for a wheeled cart.
2. Description of the Related Art
Referring to
FIG. 1
, a conventional hand brake device
1
is shown to be mounted on a handle
2
of a wheeled cart, such as a stroller or a wheelchair (not shown) and comprises a housing
10
, a brake lever
20
, and a cable pull rod
30
. The housing
10
includes a mounting portion
11
sleeved fixedly on the handle
2
of the wheeled cart, and a receiving portion
12
formed integrally with and disposed under the mounting portion
11
. The brake lever
20
has a front end portion that is provided with a fixed positioning member
21
and that is disposed within the receiving portion
12
of the housing
10
, and a lever portion
22
that extends rearwardly from the front end portion and that projects from the housing
10
. The positioning member
21
has one end pivotally connected to the housing
10
by means of a first pivot pin
13
, and the other end formed with upper and lower retaining portions
211
,
212
. The pull rod
30
is mounted in the receiving portion
12
of the housing
10
, extends transverse to the brake lever
20
, is disposed behind the positioning member
21
of the brake lever
20
, and has an upper end pivotally connected to the housing
10
by means of a second pivot pin
14
, a lower end connected fixedly to a brake cable
3
, and an intermediate portion formed with an upper protrusion
31
and a lower protrusion
32
.
In a normal operating condition of the cart, the upper and lower protrusions
31
,
32
of the cable pull rod
30
are disposed between the upper and lower retaining portions
211
,
212
of the positioning member
21
of the brake lever
20
, and the lever portion
22
of the brake lever
20
extends parallel to the handle
2
of the cart.
Referring to
FIG. 2
, when the lever portion
22
of the brake lever
20
is turned toward the handle
2
of the cart, the lower retaining portion
212
of the positioning member
21
moves to abut against the lower protrusion
32
of the pull rod
30
, thereby pushing the pull rod
30
to move rearwardly. The pull rod
30
, in turn, pulls the brake cable
3
so as to result in a braking action on the cart. The hand brake device
1
is disposed at a first braking position at this time. When the lever portion
22
of the brake lever
20
is released, the restoring force of the brake cable
3
pulls the pull rod
30
and the lever portion
22
of the brake lever
20
to their original positions shown in
FIG. 1
, thereby restoring the cart to a normal operating condition.
Referring to
FIG. 3
, when the lever portion
22
of the brake lever
20
is turned away from the handle
2
of the cart, the upper retaining portion
211
of the positioning member
21
moves past the upper protrusion
31
of the pull rod
30
, and is retained in a groove between the upper and lower protrusions
31
,
32
of the pull rod
30
so as to push the pull rod
30
rearwardly. The pull rod
30
, in turn, pulls the brake cable
3
so as to result in the braking action on the cart. The hand brake device
1
is disposed at a second braking position at this time. Even if the lever portion
22
of the brake lever
20
is released at this moment, the braking of the cart is still maintained until an external force is applied to the lever portion
22
of the brake lever
20
, thereby restoring the pull rod
30
and the lever portion
22
to their original positions shown in
FIG. 1
, and thereby restoring the cart to its normal operating condition.
Although the conventional hand brake device
1
can achieve its intended purpose, however, in actual use, the conventional hand brake device
1
is found to have the following disadvantages:
1. Since the brake lever
20
and the pull rod
30
are connected pivotally to the housing
10
at two different positions by two independent pivot pins
13
,
14
during assembly, elements of the hand brake device
1
are increased.
2. Referring to
FIG. 4
, although the lever portion
22
of the brake lever
20
can be turned to a large extent relative to the handle
2
of the cart, displacement (L) of the lower retaining portion
212
of the positioning member
21
of the brake lever
20
during braking of the cart is relatively small such that rearward displacement of the pull rod
30
and the brake cable
3
is not large, thereby reducing effectiveness of the hand brake device
1
.
3. Since the first braking position of the hand brake device
1
is frequently applied to the cart, the lower retaining portion
212
of the positioning member
21
and the lower protrusion
32
of the pull rod
30
are easily susceptible to wearing.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a hand brake device that is capable of overcoming the aforementioned drawbacks of the prior art.
According to the present invention, a hand brake device is adapted to be mounted on a handle of a wheeled cart having a brake cable. The hand brake device comprises a housing, a brake lever, and a cable pull rod. The housing includes a mounting portion adapted to be sleeved fixedly on the handle, and a hollow receiving portion connected fixedly to and disposed under the mounting portion. The receiving portion includes a front wall, two opposite lateral walls extending integrally and rearwardly from the front wall, and a pivot pin fixed in the receiving portion. The front wall has an inner wall surface that is formed with a curved limiting groove, and a bottom portion that is formed with a through hole therethrough, which is adapted to permit extension of the brake cable into the receiving portion through the through hole. The brake lever includes a pivot connecting portion, a lever portion, and a positioning block. The pivot connecting portion is disposed within the receiving portion of the housing, and has a front lower portion formed with a rounded integral projection. The lever portion extends integrally and rearwardly from the pivot connecting portion, and projects from the housing. The positioning block is connected fixedly to the front lower portion of the pivot connecting portion. The rounded integral projection of the pivot connecting portion is received fittingly within the curved limiting groove in the front wall of the housing so as to permit rotation of the lever portion of the brake lever about the rounded integral projection in a direction away from the handle. The positioning block has an abutment surface and a retaining groove, which are disposed-above and behind the rounded integral projection of the pivot connecting portion and which define a rearwardly extending protrusion therebetween. The pivot connecting portion is formed with a curved slot unit that is disposed above and behind the rounded integral projection and that has a closed front end and a closed rear end. The pivot pin of the housing extends through the rear end of the curved slot unit such that the brake lever can be turned upwardly and downwardly, thereby moving the lever portion toward and away from the handle. The cable pull rod is disposed within the receiving portion of the housing, and is located behind and abuts against the positioning block. The cable pull rod has a top end sleeved rotatably on the pivot pin of the housing, a lower end adapted to be connected fixedly to and pulled forwardly by an end of the brake cable, and a retaining portion for engaging the retaining groove in the positioning block. When the lever portion of the brake lever is turned upwardly, engagement between the retaining portion of the cable pull rod and the retaining groove and location of the pivot pin within the rear end of the curved slot unit are maintained such that the positioning block pushes the cable pull rod to turn rearwardly so as to rotate the brake lever about the pivot pin, thereby moving the rear end of the brake cable rearwardly for braking the cart, after which, upon release of the lever portion of the brake lev
Lavinder Jack
Ostrolenk Faber Gerb & Soffen, LLP
Pezzlo Benjamin A.
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