Elevator – industrial lift truck – or stationary lift for vehicle – Having specific means contacting or on load support for... – Includes movable contact component on support for engaging...
Reexamination Certificate
1999-12-09
2001-11-20
Lillis, Eileen D. (Department: 3652)
Elevator, industrial lift truck, or stationary lift for vehicle
Having specific means contacting or on load support for...
Includes movable contact component on support for engaging...
C187S373000, C187S351000, C188S188000, C188S189000
Reexamination Certificate
active
06318507
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an emergency stop apparatus for an elevator, and more particularly to an emergency stop apparatus for an elevator having a simple structure as well as effectiveness, which may facilitate to reduce manufacturing and maintaining cost.
2. Description of the Prior Art
The elevator is generally designed to ascend and descend at a regular speed in an at least two-story building. However, the elevator car often descends much faster than a normal speed for reasons of malfunction of controller or other units, especially in downward motion. In order to prevent accidents by such factors, the elevator ordinarily includes an emergency stop apparatus.
U.S. Pat. No. 5,299,661 issued on Apr. 5, 1994 discloses an elevator system having a bidirectional overspeed control device and a governor rope circularly connected to sheaves mounted to upper and lower portions of a hoist way. According to the patent, the bidirectional overspeed control device includes a bidirectional governor, safety brakes and a bidirectional linkage apparatus, in which the bidirectional governor clutches the governor rope in the event of an overspeed condition, thereby operating the bidirectional linkage apparatus which connects the governor rope to the safety.
FIG. 1
shows the emergency stop apparatus employed in such elevator system schematically. Referring to the figure, the emergency stop apparatus of the conventional elevator system is installed to an elevator car
2
moving vertically along a guide rail
1
in a hoist way inside a building. The emergency stop apparatus includes a speed governing unit
10
installed to one side of the guide rail
1
for detecting speed of the elevator car
2
in order to brake the elevator car
2
when the car
2
moves faster than a certain speed, a transmission unit
20
connected to the governor
2
for transmitting power from the speed governing unit
10
, and a brake
30
installed under the elevator car
2
for restraining the elevator car
2
by receiving power from the speed governing unit
10
through the transmission unit
20
.
The speed governor
10
includes a governor
11
, a driven pulley
12
, and a governing loop
13
. The governor
11
includes a rotating body
11
A for rotating at the same speed as speed of the elevator car
2
and stopping when the elevator car
2
moves faster than a regular speed, and a centrifugal weight
11
B having same rotary axis as the rotating body
11
B. The driven pulley
12
is mounted at a lower end of the guide rail
1
and the governing loop
13
is wound through the rotating body
11
A and the driven pulley
12
.
The transmission unit
20
includes a connecting member
21
and a multi-joint link member
22
. The connecting member
21
is combined to the governing loop
13
in order to lift at the same speed as the governing loop
13
. The multi-joint link member
22
is combined to the connecting member
21
and activates a pair of wedges
31
of the brake
30
described below when the governing loop
13
comes to a halt.
The brake
30
is well shown in
FIGS. 2 and 3
. Referring to the figures, the brake
30
includes the wedges
31
, an elastic ring
32
, a wedge seat
33
and sliding rollers
34
. When stopping the elevator car
2
in emergency, the wedges
31
are drawn by the link member
22
of the transmission unit
20
and then come in contact with the guide rail
1
. As described above, the wedges
31
in contact with the guide rail
1
make frictional force to the guide rail
1
, and at this time, the elastic ring
32
exerts vertical force to the wedges
31
in order to increase the frictional force between the wedges
31
and the guide rail
1
. The wedge seat
33
is mounted between outer sides of the wedges
31
and an inner side of the elastic ring
32
. The wedge seat
33
has is formed to become gradually narrower in its upward direction such that the wedges
31
may be pressed by more vertical force from the elastic ring
32
as the wedges
31
ascend. The sliding rollers
34
are located between the outer surface of the wedge seat
33
and the inner surface of the wedges
31
and play a role of eliminating friction between the wedges
31
and the wedge seat
33
such that the wedges
31
may ascend inside the wedge seat
33
more smoothly.
The emergency stop apparatus of the conventional elevator system as constructed above is operated as follows.
If the elevator car
2
moves in excess speed due to a breakdown or a falling in the hoist way, the governor
11
is activated by the rotating body
11
A and the centrifugal weight
11
B rotating at the same speed as speed of the elevator. The governor
11
acts for stopping the governing loop
13
moving along with the elevator car
2
. If the governing loop
13
stops, the link member
22
of the transmission unit
20
is linked to draw the wedges
31
of the brake
30
.
If the wedges
31
are drawn by the link member
22
as described above, the wedges
31
move upward inside the wedge seat
33
formed to become gradually narrower in its upward direction, and then receives strong press inward through the wedge seat
33
from the elastic ring
32
. Therefore, an inner surface of each wedge
31
comes in contact with an outer surface of the guide rail
1
, resulting that the elevator car
2
stops by frictional force generated in the contact surface.
However, such emergency stop apparatus of the conventional elevator system has a problem of low spatial utility rate because it needs separate space for installing the speed governing unit
10
having the governor
11
, the driven pulley
12
and the governing loop
13
outside the guide rail
1
. Furthermore, because a separate link member
22
should be linked for transferring action of the governor
11
to the wedges
31
, it has high manufacturing cost, and it is difficult to fabricate, install and repair the link member
22
.
SUMMARY OF THE INVENTION
Therefore, the present invention is designed to overcome such problems of the prior emergency stop apparatus. An object of the present invention is to provide an improved emergency stop apparatus of an elevator, which may increase spatial utility rate, lowers manufacturing cost, and allows fabricating, installing and repairing the apparatus easily.
In order to obtain such object, the present invention provides an emergency stop apparatus for an elevator which is vertically movable along a guide rail installed vertically to a wall of hoist way in a building, comprising: a pair of wedge means for stopping the elevator by constricting the guide rail when the elevator moves in excess speed; a flexible cable, one end of which is combined with one of the wedge means, the other end of which is combined with the other one of the wedge means, the flexible cable drawing the wedge means upward when the elevator moves in excess speed; cam means having a rotary shaft engaged with the flexible cable, the cam means drawing the cable upward when the elevator moves in excess speed; a disk roller which rides and rolls on the guide rail on the center of a rotary shaft thereof when the elevator moves, the disk roller receiving pressure from the cam means toward the guide rail when the elevator moves in excess speed; a centrifugal weight having same rotary shaft as the disk roller, the centrifugal weight rotating the cam means when the elevator moves in excess speed; and a spring, one end of which is fixed to the rotary shaft of the disk roller, the other end of which is fixed to the centrifugal weight, the spring biasing the centrifugal weight to come in contact with the cam means when the elevator moves in excess speed.
The emergency stop apparatus for an elevator may further include first spring for biasing the disk roller toward the guide rail; second spring for maintaining height of the disk roller, the second spring allowing the rotary shaft of the disk roller to move upward by contact between the cam means and the disk roller; and third spring for maintaining position of the cam means, the third spring allo
Birch & Stewart Kolasch & Birch, LLP
LG Industrial Systems Co. Ltd.
Lillis Eileen D.
Tran Thuy V.
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