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
2000-06-16
2001-05-08
Salata, Jonathan (Department: 2837)
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, C188S165000
Reexamination Certificate
active
06227334
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for checking and adjusting a speed governor of an elevator for carrying passengers or freight from one level to another.
2. Description of the Prior Art
FIG. 1
is a front view depicting a general construction of a conventional elevator governor (hereinafter referred to simply as a governor) checking and adjusting system disclosed, for instance, in Japanese Pat. Appln. No.
7-190922
; FIGS.
2
(
a
) and (
b
) are partly enlarged front and plan views of the governor checking and adjusting system shown in FIG.
1
.
In
FIG. 1
, reference numeral
12
denotes an elevator car;
13
denotes a base of the governor mounted on the roof of the elevator car
12
;
14
denotes arms rotatably attached to a rotary shaft
15
of the base
13
;
16
denotes a magnet assembly connected to the arms
14
at one end thereof to detect overspeeding of the elevator car
12
;
16
a
denotes a pair of opposed magnets bonded on a U-shaped back yoke
16
b
;
17
denotes a balance weight mounted on the arms
14
at the other end thereof such that it balances with the magnet assembly; and
18
denotes a pair of fixed conductive guide rails extending vertically along both sides of the elevator car
12
.
The magnet assembly
16
comprises the pair of magnets
16
a
disposed opposite one of the fixed conductive guide rails
18
and the back yoke
16
b
providing a path for magnetic fluxes emanating from the two magnets
16
a
. The arms
14
, the rotary shaft
15
of the base
13
, the magnet assembly
16
and the balance weight
17
constitute a force detecting mechanism.
Reference numeral
19
denotes springs both support the arms
14
and convert force exerted on the balance weight
17
, that is, a reaction force, to displacement of the balance weight
17
;
20
a
denotes an elevator car stop switch which is actuated by the displacement of the balance weight
17
;
31
denotes emergency brakes; and
32
denotes a cam for actuating a latch mechanism described below. The cam
32
is connected to one end of the rotary shaft
15
, and consequently the cam
32
turns as the rotary shaft rotates.
Reference numeral
33
denotes a latch arm,
34
a latch shaft,
35
a coupling arm, and
36
a latch pin, which constitute the latch mechanism that operates in ganged relation to the cam
32
. Reference numeral
21
denotes a pull-up rod, and
22
pull-up springs, which constitute a transmission for transmitting instructions for the actuation of the emergency brakes
31
, the pull-up rod
21
being coupled by the latch pin
36
to the latch mechanism.
The elevator employing the present invention is of the type that the elevator car
12
for freight or passengers moves up and down in an elevator hoistway in a steel tower or high-rise building and that a speed governor is loaded on the elevator case
12
as a substitute for governor ropes used in the past. In a machine room at the top of the elevator hoistway there are provided a hoist, a switchboard (both not shown) and so on; the elevator car
12
and a balance weight (not shown) hang from the hoist such that the elevator car
12
is moved up and down just like a well bucket. In the elevator hoistway there are provided the fixed conductor guides
18
for the elevator car
12
and the balance weight, and in a pit at the bottom of the elevator hoistway there are placed buffers (not shown) for the elevator car
12
and the balance weight.
The above-described governor operates as follows.
As depicted in FIGS.
2
(
a
) and (
b
), the magnet assembly
16
made up of the magnets
16
a
and the back yoke
16
b
produces a magnetic field in the flange or vane of the fixed conductive guide rail
18
positioned between the opposed magnets
16
a
. Upon the magnetic field traveling in the fixed conductive guide rail
18
as the elevator car
12
moves up or down, an eddy current is induced in the guide rail
18
which cancels intensity variations of the magnetic field, causing the magnet assembly
16
to produce an electromagnetic reaction force of a magnitude corresponding to the speed of the elevator car
12
in a direction opposite to the up or down run direction of the elevator car
12
. The reaction force thus produced is converted by the arms
14
and the springs
19
to upward or downward displacement of the magnets
16
a
and the balance weight
17
.
When the ascent/descent speed of the elevator car
12
has reached a first overspeed value (normally approximately 1.3 times higher than a rated speed, see
FIG. 3
) in excess of a predetermined value, a force corresponding to the increased speed of the elevator car
12
is exerted on the magnet assembly
16
, causing the balance weight
17
to be displaced accordingly. And, when this displacement reaches a first operating point, the elevator car stop switch
20
a
equipped in a brake operates to tun off the power supply of the elevator drive system, bringing the elevator car
12
to a stop. Even in the case where the ascent or descent speed of the elevator car
12
reaches a second overspeed value (normally about 1.4 times higher than the rated speed, see.
FIG. 3
) for some reason and the displacement of the balance weight
17
goes up to a second operating point, the balance weight
17
is further displaced corresponding to the increased speed of the elevator car
12
, and the cam
32
ganged with the balance weight
17
turns, causing the latch arm
33
to enter into a recess
30
of the cam
32
. Then the pull-up rod
21
is pulled down by the pull-up springs
22
through the latch mechanism, and the emergency brakes
31
mounted on the elevator car
12
are actuated to drive wedges into the fixed guide rails
18
, bringing the elevator car
12
to a quick stop by friction.
Such a speed governor must be checked for normal operation responsive to the overspeeding elevator car at the time of installation or maintenance, but no method therefor has been established so far. And the speed governor may sometimes need on-site adjustment, but no system or scheme therefor has been implemented, either.
Because of such a construction as described above, the conventional governor has a problem that no methods have been established for checking and adjusting its operation during on-site installation or maintenance.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an elevator governor checking and adjusting method that permits simple and accurate inspection and maintenance of the governor.
According to an aspect of the present invention, during checking and adjustment of the governor an emergency stop mechanism with latch means for actuating emergency brakes is held disconnected from the latter which grabs a first fixed conductive guide rail to stop an elevator car assembly by friction. This ensures preventing the operation of the emergency brakes, and hence permits checking and adjustment of the governor with safety.
According to another aspect of the present invention, the elevator governor is checked and adjusted without disconnecting the latch means from the emergency brakes. This enables the governor to be checked and adjusted under exactly the same conditions as in the actual operation of the elevator, and hence provides increased accuracy in checking and adjusting the governor.
According to another aspect of the present invention, since first and second fixed conductor guides are made of the same material, they can be used as guides rails, too, which extend vertically the entire length of the elevator hoistway.
According to another aspect of the present invention, the elevator car is acrtualy driven to move in an up or down direction and a check is made to see whether the emergency stop switch and the emergency stop mechanism normally operate when the travel speed of the elevator car has reached predetermined first and second critical speeds. This permits simple and low-cost inspection and adjustment of the governor.
According to another aspect of the present invention, a force-displacement conver
Okada Mineo
Yumura Takashi
Mitsubishi Denki & Kabushiki Kaisha
Salata Jonathan
Sughrue Mion Zinn Macpeak & Seas, PLLC
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