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
2000-05-02
2002-03-26
Brahan, Thomas J. (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...
Reexamination Certificate
active
06360847
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a speed governing apparatus that detects over-speed of an ascending/descending member, such as an elevator car or a counterweight, and stops the ascending/descending member, and an elevator system having the speed governing apparatus.
2. Description of Related Art
FIG. 1
is a longitudinal sectional view showing a conventional fly ball type speed governor disclosed in, for example, Japanese Unexamined Patent Publication No. 3-177283.
A system shown in
FIG. 1
has a machine room
1
provided right above a hoistway, a speed governor
2
installed on the machine room
1
, and an endless speed governing rope
3
which is disposed in the hoistway and one end of which is coupled to an ascending/descending member (not shown).
The system further includes a support member
4
of the speed governor
2
, a horizontal shaft
5
rotatably held by the support member
4
, a sheave
6
which is secured to the horizontal shaft
5
and onto which an upper end curved portion of the speed governing rope
3
has been wound, a perpendicular shaft
7
rotatably held above the support member
4
, a driving bevel gear
8
that is secured to the horizontal shaft
5
and concentrically disposed to a rotational center of the sheave
6
, and a driven bevel gear
9
that is secured to the perpendicular shaft
7
and in engagement with the driving bevel gear
8
.
Reference numeral
10
denotes a well-known fly ball type speed governing mechanism provided on the perpendicular shaft
7
. The fly ball speed governing mechanism
10
includes arms
11
having their upper ends pivotally held by an upper end portion of the perpendicular shaft
7
, fly balls
12
secured to lower ends of the arms
11
, a slide cylinder
13
fitted onto the perpendicular shaft
7
, links
14
having both ends pivotally mounted on middle portions of the arms
11
and on the slide cylinder
13
, and a balance spring
15
which is composed of a compression coil spring fitted to the perpendicular shaft
7
and disposed between the upper end of the perpendicular shaft
7
and the slide cylinder
13
to urge the slide cylinder
13
downward.
A driven cylinder
16
is fitted onto the perpendicular shaft
7
, and pivotally attached to the slide cylinder
13
so that it is vertically moves as the slide cylinder
13
vertically moves; however, it does not rotate about the perpendicular shaft
7
. A stop switch
17
is secured to the support member
4
and turns OFF the power of a driving unit (not shown) for driving the ascending/descending member. An operating lever
18
is secured to the driven cylinder
16
to operate the stop switch
17
as the driven cylinder
16
ascends.
The conventional fly ball type speed governor is disposed and constructed as described above, and as the ascending/descending member ascends or descends, the movement of the speed governing rope
3
causes the sheave
6
to rotate. This rotation is transmitted to the perpendicular shaft
7
via the driving bevel gear
8
and the driven bevel gear
9
. The fly balls
12
revolve according to a rotational speed of the perpendicular shaft
7
, and move up against the urging force of the balance spring
15
due to a centrifugal force.
As the fly balls
12
rise, the slide cylinder
13
and the driven cylinder
16
are displaced upward. If the rotational speed of the perpendicular shaft
7
, that is, the ascending or descending speed of the ascending/descending member, exceeds a rated speed and reaches a first over-speed (the first over-speed is defined by the rated speed and represented by the code as ASME/ANSI A17.1-1987 SAFETY CODE FOR ELEVATORS AND ESCALATORS), the stop switch
17
is operated by the operating lever
18
to cut off the power of the driving unit of the ascending/descending member to thereby stop the ascending/descending member. If the ascending/descending member should be further over-speed downward due to some cause and reach a second over-speed from the first over-speed, an emergency stop unit (not shown) of the ascending/descending member is actuated, although detailed descriptions and illustrations thereof will be omitted.
FIG. 2
is a front view showing a conventional fly weight type speed governor disclosed in, for example, Japanese Unexamined Patent Publication No. 6-1564.
FIG. 3
is a cross-sectional view of the fly weight type speed, governor.
The speed governor shown in the drawings include a base
21
having a U-shaped cross section, bearing boxes
22
which are disposed on side walls of the base
21
and in which bearings
23
are provided, a shaft
5
having its both ends rotatably supported by the bearings
23
, a sheave
6
secured to the shaft
5
, and fly weights
26
which are arranged to face each other on side surfaces of the sheave
6
via the shaft
5
and pivotally attached to the sheave
6
, and weight sides thereof are rotationally displaced in a direction orthogonal to an axis of the shaft
5
.
A balance spring
27
has one end thereof in engagement with an anti-weight side of the fly weight
26
, while the other end thereof in engagement with a side surface of the sheave
6
, and acts against a displacement of the fly weight
26
caused by the centrifugal force produced when the sheave
6
rotates. An actuating hook
28
is provided on the same side of the fly weight
26
where the balance spring
27
is in engagement. An actuating member
29
is composed of a bolt screwed in the weight side of the fly weight
26
. A link
210
has its both ends disposed on opposite sides from each other with respect to pivoting points of the two fly weights
26
.
A stop switch
211
is mounted on a base
21
and has an actuating assembly
212
opposed to the actuating member
29
.
A ratchet
213
is rotatably held by the shaft
5
and disposed to face against the actuating hook
28
. A brake arm
214
has its lower end pivotally attached to the base
21
and has a brake piece
215
attached to its middle portion. An actuating bar
216
has one end thereof pivotally attached in the vicinity of the rim of the ratchet
213
, and a threaded bar on the other end thereof is movably inserted in an upper end portion of the brake arm
214
, a spring shoe
217
being held by a nut
218
at an insertion end.
A compression coil spring
219
is fitted onto the screwed bar of the actuating bar
216
, and disposed between the brake arm
214
and the spring shoe
217
. The speed governing rope
3
is wound around the sheave
6
, and one end thereof is retained on an ascending/descending member, such as a car, of an elevator system provided in a hoistway, although not shown in the drawings.
The conventional fly weight type speed governor is constructed as described above, and the sheave
6
rotates by being driven by the speed governing rope
3
that moves together with the ascending/descending member. As the sheave
6
rotates, the fly weights
26
revolve together with the sheave
6
, and if the rotational speed of the sheave
6
, that is, the speed of the ascending/descending member, reaches a first over-speed (the first over-speed is defined by the rated speed and represented by the code as ASME/ANSI A17.1-1987 SAFETY CODE FOR ELEVATORS AND ESCALATORS) that exceeds a predetermined value, a centrifugal force causes a rotational displacement of the fly weights
26
against the urging force of the balance spring
27
. The rotational displacement of the fly weights
26
causes the actuating member
29
to press the actuating assembly
212
of the stop switch
211
. This actuates the stop switch
211
to cut off the power of the driving unit of the elevator system so as to stop the ascending/descending member, thus preventing an accident caused by the occurrence of the first over-speed.
However, in case of an accident, such as breakage of a main rope of the elevator system, the ascending/descending member continues to descend even when the driving unit is stopped. In this case, if the ascending/descending member reaches a second over-speed (the second over-speed is defined
Hayashi Yoshikatsu
Okada Mineo
Brahan Thomas J.
Leydig , Voit & Mayer, Ltd.
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