TECHNICAL FIELD
The present invention relates to an elevator speed governor
installed inside a hoistway for detecting overspeed of a car and
to an elevator apparatus using that speed governor.
BACKGROUND ART
In conventional elevator apparatuses, if a speed of a car reaches
a preset overspeed, emergency stopping apparatuses mounted to the
car are activated by a speed governor to make the car perform an
emergency stop.
In a resetting operation after an emergency stop, a braked
state of the emergency stopping apparatuses is released, then the
resetting operation is performed on the speed governor. In elevator
apparatuses in which the speed governor is disposed in an upper
portion inside a hoistway instead of in a machine room, maintenance
personnel must open landing doors from a landing on an uppermost
floor, climb on top of the car, and reach for the speed governor
from on top of the car to perform the resetting operation.
However, if the emergency stop position of the car is in a
vicinity of the landing on the uppermost floor, it may not be possible
transfer to the roof of the car even if the landing doors are opened.
In that case, it is possible to raise the car to release the braked
state of the emergency stopping apparatuses on car guide rails,
but it is not possible to lower the car so that the maintenance
personnel can climb onto the car.
In regard to this, it is conceivable that a resetting opening
could be disposed in a wall portion of the landing on the uppermost
floor, for example, for maintenance personnel to perform the
resetting operation on the speed governor by inserting a hand through
this resetting opening into the hoistway.
However, in order to provide the resetting opening,
construction work is required to open an aperture in the wall portion,
making extra work and also lowering fire-resistance and design
properties. Furthermore, since the resetting opening must be
positioned significantly higher than the landing door, and the speed
governor is also positioned far back from the resetting opening,
a resetting operation through a resetting opening is difficult.
DISCLOSURE OF THE INVENTION
The present invention aims to solve the above problems and
an object of the present invention is to provide an elevator speed
governor enabling a resetting operation to be performed easily even
if an emergency stop position of a car is in a vicinity of a landing
on an uppermost floor, and to provide an elevator apparatus using
that speed governor.
In order to achieve the above object, according to one aspect
of the present invention, there is provided an elevator speed governor
including: a speed governor main body disposed in an upper portion
inside a hoistway, for detecting when a speed of a car reaches a
preset overspeed and operating to activate an emergency stopping
apparatus mounted to the car; a reset assisting mechanism disposed
on the speed governor main body and having an externally-operated
acting lever, the acting lever being operated to assist in an operation
for resetting the speed governor main body; and an operating member
disposed on an upper portion of the car, for pressing and operating
the acting lever.
According to another aspect of the present invention, there
is provided an elevator apparatus including: a car that is raised
and lowered inside a hoistway; an emergency stopping apparatus
mounted to the car, for making the car perform an emergency stop;
a speed governor main body disposed in an upper portion inside the
hoistway, for detecting when a speed of the car reaches a preset
overspeed and operating to activate the emergency stopping
apparatus; a reset assisting mechanism disposed on the speed governor
main body and having an externally-operated acting lever, the acting
lever being operated to assist in an operation for resetting the
speed governor main body; and an operating member disposed on an
upper portion of the car, for pressing and operating the acting
lever.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a structural diagram showing an elevator apparatus
according to an example of a preferred embodiment of the present
invention;
Figure 2 is a front elevation showing a speed governor main
body from Figure 1;
Figure 3 is a front elevation showing part of Figure 2; and
Figure 4 is a front elevation showing a state in which a resetting
lever from Figure 3 is swung to a reset position.
BEST MODE FOR CARRYING OUT THE INVENTION
A preferred embodiment of the present invention will now be
explained with reference to the drawings.
Figure 1 is a structural diagram showing an elevator apparatus
according to an example of a preferred embodiment of the present
invention. In the figure, a driving machine 2 is installed in an
upper portion inside the hoistway 1. A main rope 3 is wound onto
a drive sheave 2a of the driving machine 2. A car 4 is suspended
by a first end portion of the main rope 3, and a counterweight 5
is suspended by a second end portion of the main rope 3. A pair
of car guide rails 6 and a pair of counterweight guide rails (not
shown) for guiding raising and lowering of the car 4 and the
counterweight 5 are installed inside the hoistway 1.
An emergency stopping apparatus 7 for making the car 4 perform
an emergency stop is mounted to a lower portion of the car 4. A
speed governor supporting member 8 is secured in a vicinity of an
upper end portion of the car guide rails 6. A speed governor main
body 9 for detecting overspeed of the car 6 and activating the
emergency stopping apparatus 7 is supported on this speed governor
supporting member 8.
A rotatable tension sheave 10 is disposed in a vicinity of
a bottom portion of the hoistway 1. A loop-shaped speed governor
rope 11 is wound around the speed governor main body 9 and the tension
sheave 10. The speed governor rope 11 is connected to the emergency
stopping apparatus 7 by means of a lever 12, and is moved cyclically
together with the raising and lowering of the car 4.
A landing door 14 is disposed on a landing 13. A bar-shaped
operating member (operating cam) 75 is secured to an upper portion
of the car 4 so as to stand upright. The operating member 75 is
disposed so as to be brought into close proximity with the speed
governor main body 9 if the car 4 moves above the landing 13 on
the uppermost floor.
Figure 2 is a front elevation showing the speed governor main
body 9 from Figure 1. In the figure, a sheave 21 around which the
speed governor rope 11 is wound is supported by a base 23 so as
to be rotatable around a sheave shaft 22. A pair of first and second
flyweights 25 that are pivotable around first and second pins 24
aremountedto side surfaces of the sheave 21. This pair of flyweights
25 are linked to each other by a link 26.
A moving pawl 37 is secured to a first end portion of the first
flyweight 25. The first flyweight 25 is pivoted by centrifugal force
due to the rotation of the sheave 21. Thus, the moving pawl 37 is
displaced radially outwards relative to the sheave 21. A balancing
spring 27 opposing the centrifugal force is disposed between a second
end portion of the first flyweight 25 and the sheave 21. A
car-stopping switch 28 for activating a braking apparatus (not shown)
of the driving machine 2 is mounted to the base 23. The car-stopping
switch 28 has a switching lever 28a that is operated by the moving
pawl 37.
A trip lever 72 that is pivotable around a shaft 71 that is
parallel to the first pin 24 is mounted to the sheave 23. A portion
of the trip lever 72 is placed in contact with the first flyweight
25, and is pivoted around the shaft 71 by the pivoting of the first
flyweight 25. A torsion spring 73 for applying force in a direction
that places the trip lever 72 in contact with the first flyweight
25 (clockwise in the figure) is disposed on the shaft 71.
A ratchet 30 that is rotatable around the sheave shaft 22 is
disposed on the base 23. A large number of teeth are disposed on
an outer peripheral portion of this ratchet 30. A pawl 29 that
selectively engages with either the trip lever 72 or the ratchet
30 is pivotably supported by the first pin 24. The pawl 29 is forced
by a retracting spring 74 in such a direction as to engage the ratchet
30. The pawl 29 is normally engaged with the trip lever 72, and
separated from the ratchet 30, but when disengaged from the trip
lever 72, the pawl 29 is pivoted by the force of the retracting
spring 74 and engages with the teeth of the ratchet 30.
A shoe 32 that is pressed against the speed governor rope 11
is pivotably mounted to an arm 31 pivotably mounted to the base
23. A spring shaft 33 is passed through a spring bearing portion
31a of the arm 31. A connecting lever 34 is connected between a
first end portion of the spring shaft 33 and the ratchet 30. A spring
bearing member 35 is disposed on a second end portion of the spring
shaft 33. A rope gripping spring 36 for pressing the shoe 32 against
the speed governor rope 11 is disposed between the spring bearing
portion 31a and the spring bearing member 35.
A resetting lever 42 is mounted to the base 23. The resetting
lever 42 is swingable around a shaft 43 that is parallel to the
sheave shaft 22. A rotatable lug 44 that is pressed by the swinging
of the resetting lever 42 is disposed on the pawl 29. A return spring
45 for forcing the resetting lever 42 in such a direction as to
separate from the lug 44 is disposed between the base 23 and the
resetting lever 42.
An acting lever 76 that is operated externally so as to be
pivoted together with the resetting lever 42 around the shaft 43
is mounted to the shaft 43. A reset assisting mechanism in this
embodiment includes: the resetting lever 42; the shaft 43; the lug
44; the return spring 45; and the acting lever 76. This reset
assisting mechanism allows the acting lever 76 to be operated to
reset a portion of the mechanism of the speed governor main body
9, specifically the pawl 29 and the trip lever 72, from an active
state due to overspeed detection to the state before activation.
In other words, the reset assisting mechanism assists an operation
for resetting the speed governor main body 9.
The elevator speed governor in this embodiment includes: the
speed governor main body 9; the reset assisting mechanism; and the
operating member 75.
Figure 3 is a front elevation showing part of Figure 2, and
Figure 4 is a front elevation showing a state in which the resetting
lever 42 from Figure 3 is swung to a reset position. In Figure 3,
the resetting lever 42 is in a normal position, and is separated
from the lug 44. From the state in Figure 3, if the operating member
75 is displaced upward, the acting lever 73 is pressed by the operating
member 75 and pivoted, and the resetting lever 42 is also swung
to the reset position in opposition to the return spring 45. Thus,
the lug 44 is pressed by the resetting lever 42, and the pawl 29
is pivoted clockwise in the figure in opposition to the retracting
spring 74, and engages with the trip lever 72.
Next, operation will be explained. If the elevating speed of
the car 4 reaches a first overspeed (normally around 1.3 times a
rated velocity), the moving pawl 37 is placed in contact with the
switch lever 28a of the car-stopping switch 28 by pivoting of the
flyweights 25 due to centrifugal force, pivoting the switch lever
28a. Thus, the switch 28 is activated, interrupting the power source
of the driving machine 2, and the car is stopped by the braking
apparatus of the driving machine 2.
If the main rope 3 breaks, for example, and the car 4 continues
to descent without stopping, even though the driving machine 2 has
stopped, when the descent speed of the car 4 reaches a second overspeed
(normally around 1.4 times the rated velocity), the flyweights 25
pivot further, and the amount of pivoting of the trip lever 72 also
increases together therewith, dislodging engagement between the
trip lever 72 and the pawl 29. In this manner, the pawl 29 is pivoted
by the force of the retracting spring 74 and engages with the teeth
of the ratchet 30. Thus, the ratchet 30 is rotated counterclockwise
in Figure 2 together with the sheave 21.
Due to this rotation of the ratchet 30, the arm 31 is pivoted
counterclockwise in Figure 2, the shoe 32 is placed in contact with
the speed governor rope 11, and the shoe 32 is pressed against the
speed governor rope 11 by the rope gripping spring 36, braking the
speed governor rope 11. When cycling of the speed governor rope
11 is stopped, the lever 12 is actuated by the car 4 as it continues
to descend, activating the emergency stopping apparatuses 7.
Next, a resetting operation after activation of the emergency
stopping apparatuses 7 and the speed governor main body 9 will be
explained. In the resetting operation, first the car 4 is raised
slightly to release the braked state of the emergency stopping
apparatus 7 on the car guide rails 6. Then, when the car 4 is raised
further, the sheave 21 is pivoted in a clockwise direction in Figure
2 by means of the speed governor rope 3, disengaging the pawl 29
and the ratchet 30, and the ratchet 30 also pivots clockwise in
the figure, returning to its original position. Thus, the arm 31
returns to its original position, and the shoe 32 separates from
the speed governor rope 11.
After this, the car 4 is raised to a position from which it
is possible to climb in onto the roof of the car 4 from the landing
13 of the uppermost floor, then the landing door 14 of the landing
13 of the uppermost floor is opened, and maintenance personnel climb
onto the car 4. Then, the resetting operation is completed by
reaching for the speed governor main body 9 from on top of the car
4, and engaging the pawl 29 in the trip lever 72.
Thus, if the maintenance personnel can climb onto the car 4,
the pawl 29 can be engaged in the trip lever 72 manually, and it
is not necessary to use the reset assisting mechanism.
On the other hand, if the position of the car 4 when the speed
governor main body 9 performs the second overspeed operation is
in the vicinity of the landing 13 of the uppermost floor, and it
is not possible to open the landing door 14 and climb in onto the
roof of the car 4 from that position, the car 4 is raised further,
and the acting lever 76 is pressed using the operating member 75.
Thus, on the speed governor main body 9, the resetting lever 42
is pivoted in a clockwise direction in Figures 2 to 4 in opposition
to the return spring 45, and the lug 44 is pressed by the resetting
lever 42. Thus, the pawl 29 is pivoted in a clockwise direction
in Figures 2 to 4 in opposition to the retracting spring 73, and
engages with the trip lever 72.
Moreover, if the resetting lever 42 and the lug 44 are not
in a positional relationship facing each other, the car 4 is simply
raised for a while in that state to rotate the sheave 21 in a clockwise
direction. Thus, the operating member 75 continues to be placed
in contact with the acting lever 76, and the lug 44, which rotates
together with the sheave 21, is placed in contact with the resetting
lever 42 in the reset position and pressed.
By operating in this manner, even if the car 4 is in the vicinity
of the landing 13 on the uppermost floor and it is not possible
to open the landing door 14 and climb in onto the roof of the car
4 from that position, the pawl 29 can be engaged in the trip lever
72 by remote control from the landing 13.
Consequently, even if the speed governor main body 9 is disposed
inside the hoistway 1, the resetting operation can be performed
on the speed governor main body 9 easily from a remote location
without having to dispose an opening for accessing the speed governor
main body 9 in the landing wall, thereby enabling workability of
the resetting operation to be improved.
Furthermore, it is also no longer necessary to lay wires, etc.,
for remote control from the speed governor main body 9 to the landing
13, enabling reductions in the degree of freedom of the equipment
layout inside the hoistway 1 to be prevented.
Moreover, even if the emergency stopping apparatus 7 is
activated below the uppermost floor, it is possible to use the
operating member 75 to perform the resetting operation without the
maintenance personnel having to climb in on top of the car 4. However,
because complicated procedures such as releasing the safety
apparatus, for example, may be required in order to move the car
4 above the landing position of the uppermost floor, it is often
simpler to climb in on top of the car 4 as described above.
In the above example, the operating member 75 is fixed on top
of the car 4, but the operating member may also be made vertically
movable relative to the car 4. In that case, the resetting operation
can be performed using the operating member without having to move
the car 4 above the landing position of the uppermost floor.
Furthermore, if the operating member is made vertically movable,
it may be raised and lowered manually from inside the cabin, or
it may also be raised and lowered by a driving force such as from
an electric motor, etc.
In addition, in the above example, a "machine-roomless"
elevator is described, but the present invention can also be applied
to elevator apparatuses having a machine room provided that the
speed governor is disposed in an upper portion inside the hoistway.