Brakes – To retard rolling of caster
Reexamination Certificate
2000-12-15
2002-04-23
Schwartz, Christopher P. (Department: 3613)
Brakes
To retard rolling of caster
C188S020000, C188S082840
Reexamination Certificate
active
06374954
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a baby walker, particularly to a baby walker speed control caster for a safety concern.
B. Description of the Related Art
The baby walker is commonly used for babies learning to walk. However, most of the conventional baby walkers do not perform a self-braking effect, hence putting the baby in danger when the speed of the baby walker goes too high especially on a downhill or an uneven roadway. Generally, the self-braking device for a baby walker can be realized as the speed control caster.
Referring to
FIGS. 1 and 2
, a conventional speed control caster
40
for the baby walker generally includes a wheel
41
, a ring groove
42
provided at one flank of the wheel
41
and formed with a wavy ball trough
421
, a fixing piece
43
, a ball
44
, a convex shaft tube
45
having a through hole
451
and being integrally formed together with the ring groove
42
at the interior of the caster, and a shaft rod
46
.
As shown in
FIGS. 1 and 2
, the fixing pieces
43
is provided with a central through hole
431
for loosely pivoting with the convex shaft tube
45
such that the fixing pieces
43
is put into the ring groove
42
. The shaft rod
46
, being formed with a rivet-shaped end
461
, is fastened to the pivot holes
401
and
402
of the wheel seat
30
respectively by passing through the through hole
431
and
451
such that the wheel
41
runs by pivoting on the shaft rod
46
. Referring to
FIG. 2
, the ball tough
421
is shaped into three kinds of arcs which are arc
432
, protruding arc
433
, and concave arc
434
respectively. When the wheel
40
revolves, the ball
44
is pushed forward by the wavy contour of the ball trough
421
such that the ball
44
rolling back and forth a long the ball trough
421
is squeezed between the ring groove
42
and the protruding arc
433
as the ball
44
is swung toward the concave arc
434
. As the speed of the caster
40
becomes higher, the frictional force caused between the protruding arc
433
and the ring groove
42
by squeezing the ball
44
gets larger as to result in a braking effect.
The conventional speed control caster
40
is disadvantaged for the following:
1. The frictional force caused between the protruding arc
433
and the ring groove
42
can hardly afford an obvious braking effect for a speed control caster.
2. The protruding arc
433
tends to be deformed after the speed control caster is used for a period of time.
3. The fixing piece
43
does not revolve as the wheel
41
but swing about the convex shaft tube
45
, thus hindering the wheel agility at a relatively low speed.
4. The conventional speed control caster has a complex structure resulting in a high-level damage rate and a high manufacturing cost.
SUMMARY OF THE INVENTION
One of the objects of the invention is to provide a baby walker speed control caster including an axle piece, a pair of wheels symmetrically provided at either side of the axle piece, and a ball. The axle piece is provided with a pivot hole, a through hole, and a pivot shaft. Each wheel is formed in a thickness radially increasing respectively from the adjacency of the wheel center and is provided with a pivot hole a t the center and a plurality of embossing curves at the inner side; in this way, the wheels are pivotably connected to each other by a pivot axle passing through the pivot holes of the wheels and the axle piece sandwiched between the wheels such that a chamber, containing the ball, is formed by the through hole of the axle piece and the inner walls of the wheels and the width between two inner walls decreases radially from the adjacency of the wheel center. By this structure, a baby walker is effectively braked while in high speed, and the embossing curves leading the ball upward along the elongation of the chamber can hardly diminish the agility of the speed control caster. Besides, the wheels of the speed control caster are also advantaged for the low cost and simple design with a persistent thickness of the wheel, thus maintaining a constant braking effect.
REFERENCES:
patent: 2960717 (1960-11-01), Moore
patent: 3623575 (1971-11-01), Schiltigheim
patent: 4603871 (1986-08-01), McNeill
patent: 5465986 (1995-11-01), MacPae
patent: 5785154 (1998-07-01), Chen
patent: 6070701 (2000-06-01), Hu
patent: 6076839 (2000-06-01), Pao-Hung
patent: 6142261 (2000-11-01), Yang
patent: 0354827 (1990-02-01), None
patent: 2-248726 (1990-10-01), None
King Bradley
Kingstar Baby Carriages Co., Ltd.
Schwartz Christopher P.
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