Miscellaneous hardware (e.g. – bushing – carpet fastener – caster – Casters – Locked
Reexamination Certificate
1999-10-28
2001-04-24
Mah, Chuck Y. (Department: 3626)
Miscellaneous hardware (e.g., bushing, carpet fastener, caster,
Casters
Locked
Reexamination Certificate
active
06219881
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improved brake for caster and particularly to an improved brake that uses a brake pad to make forced contact with a caster wheel for braking.
BACKGROUND OF THE INVENTION
FIGS. 1 and 2
show a typical conventional brake means
2
for a wheel
1
in a caster.
The brake means
2
constitutes a bracket
21
, a load seat
22
, a brake body
23
, and the wheel
1
.
The bracket
21
is a reversed-U shape member and includes two side walls
211
and a top wall
213
. The side walls
211
have two lower pivot holes
2112
, a front shaft
2114
and a rear shaft
2116
. The top wall
213
has an upper pivot hole
2132
. The wheel is pivotly held by a bolt between the lower pivot holes
2112
.
The load seat
22
includes a load plate
221
, an upper cap
222
and a lower cap
223
. The upper and lower caps
222
and
223
are mating against each other at two opposite side of the upper pivot hole
2132
. In the caps
222
and
223
, there are a plurality of steel balls
224
located thereon (also referring to FIG.
3
). The load plate
221
is located above the upper cap
222
. The lower cap
223
has slots
225
radically formed at the bottom. The load seat
22
may be freely rotating.
The brake body
23
includes a friction plate
231
and a pedal
232
. The friction plate
231
is a<shaped member including an upper spring plate
2311
and a lower spring plate
2312
. The upper spring plate
2311
has a brake tooth
2312
formed at one end. The pedal
232
has an ellipse cam
2322
formed at one end thereof which is engaged with the rear shaft
2116
. The friction plate
231
has a front end pivotally engaged with the front shaft
2114
(shown in FIG.
3
). The cam
2322
is held on the pedal
232
firmly.
Referring to
FIG. 3
, in the conventional caster the brake means
2
is engaged with the load plate
22
and is located at a lower portion of the caster. For braking the caster, the pedal
232
is pressed downward which turns the cam
2322
which in turn pushes the upper and lower spring plates
2311
and
2312
outward against each other until the brake tooth
2312
engaging with the slot
225
and the lower spring plate
2312
pressing against the wheel
1
for preventing the wheel from moving. The wheel
1
will also be prevented from turning (due to engagement of the brake tooth
23112
with the slot
225
) (shown in FIG.
4
). For releasing the brake, the pedal
232
is moved upward to return the cam
2322
to its initial position (FIG.
3
). The upper and lower spring plates
2311
and
2312
are disengaged respectively with the slot
225
and the wheel
1
. Then the wheel
1
may be moved and turned again.
There are disadvantages in the conventional caster mentioned above. For instance, when releasing the brake, the pedal
232
shall be moved up by people, mostly by hand. It is awkward for people to bend down to reach the pedal. The hand get smeared easily. Moreover the brake means
2
usually is mounted on the bracket
21
. When the wheel
1
changes direction, the pedal
232
also change direction and might become non-accessible to users (e.g., being swivelled under the cart under which the casters are mounted). Trying to get the pedal moved out for people use is troublesome and could easily cause human injury or cause the cart to bump against other object or wall, and result in damage.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved brake for caster that is operaionable by single foot either for braking or brake releasing to enhance maneuverability of the cart.
It is another object of this invention to provide an improved brake for caster that has a fixedly located brake pedal non-movable against the turning of the caster wheels for enhancing user convenience and maneuverability of the cart.
In one aspect, this invention includes a bracket, a wheel, a load seat, a lever, a spring and a brake body.
The bracket is formed in a reverse-U shape having two side walls and a top wall. The side walls have a pair of pivot holes for supporting a lower shaft to held the wheel. The top wall has an upper pivot hole formed therein.
The load seat constitutes two symmetrical side flanges connecting by a load plate located therebetween and a shaft which has a center round opening mating against a round bore formed in the center of the load plate. The shaft further has a plurality of deep grooves and shallow grooves formed alternately around the center opening.
The brake body includes a brake pad, an upper bar and a lower bar. The upper bar is a hollow tube having a plurality of first lugs formed on outside circumference mating with the deep and shallow grooves and jigsaw teeth formed at a bottom rim. The low bar is also a hollow tube having a barrel and a sleeve engageable with inside wall of the upper bar. The barrel has a plurality of second lugs formed on outside circumference mating with the deep grooves and jigsaw teeth formed at a top rim.
The brake pad has a stem passing through the lower and upper bar in the center and having an enlarged top end extending out of the round bore of the load plate. There is a spring located below the enlarged top end and above the load plate. The lever includes a fulcrum, a force applying point formed in a pedal, and a force reaction point between the fulcrum and the force applying point and making contact with the top end of the stem.
Through pressing the pedal (force applying point), the brake body will be moved downward to make forced contact between the brake pad and the wheel. The upper bar also will be moved downward for the top rim to press against the jigsaw bottom rim of the lower bar and drives the lower bar to turn. When the applying force is released, the second lugs of the low bar engages with the shallow grooves to lock and keep braking the wheel. When pressing the pedal (force applying point) for the second time, the brake body will be moved down again, the upper bar will trigger the low bar to turn again, but this time the second lugs will engage with the deep grooves. When the pedal is released again, the spring will push the stem and the brake upward to free the wheel from the brake pad. Then the brake is released.
REFERENCES:
patent: 2138433 (1938-11-01), Sunden
patent: 2709828 (1955-06-01), Noelting et al.
patent: 3162888 (1964-12-01), Mobus
patent: 3911525 (1975-10-01), Haussels
patent: 4205413 (1980-06-01), Collignon et al.
patent: 4349937 (1982-09-01), Fontana
Dougherty & Troxell
Mah Chuck Y.
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