Braking device and hoisting machine having same

Information

  • Patent Grant
  • 6796548
  • Patent Number
    6,796,548
  • Date Filed
    Thursday, September 19, 2002
    22 years ago
  • Date Issued
    Tuesday, September 28, 2004
    20 years ago
Abstract
A braking device includes a brake wheel, a pair of rotation shafts, a pair of brake arms which is rotatably supported through the rotation shafts, a pair of brake pads arranged at one end of the brake arms and contacting and separating from the brake wheel, and a brake part connected to another end of the brake arms for providing and releasing a braking force of the brake pads. When the centers of the rotation shafts are fulcrums, the centers of contact of the brake pads with the brake wheel are points of action, and the connections between the brake arms and the brake part are power points, the fulcrums, the points of action, and the power points are located in a semicircular area of the brake wheel.
Description




BACKGROUND OF THE INVENTION




The present invention relates to a braking device and a hoisting machine having the braking device, which are suitable for use, particularly, in elevator systems.




An elevator system provided with a hoisting machine is disclosed in P2000-16727A. This elevator system comprises a support arranged at an upper part of a hoistway and a hoisting machine supported thereon. The hoisting machine comprises a sheave on which a rope is wound to support a car.




With the above elevator system, however, there arises a problem that a braking device is increased in size in the radial direction, which causes upsizing of the hoisting machine provided with the braking device. On the other hand, along a recent tendency of elimination of a machine room in the field of elevators, the hoisting machine is often disposed in the hoistway of the elevator system, requiring downsizing of the hoisting machine.




SUMMARY OF THE INVENTION




It is, therefore, an object of the present invention to provide a braking device and a hoisting machine having the braking device, which are reduced in size.




The present invention provides generally an arrangement which comprises: a rotatable brake wheel; a pair of rotation shafts; a pair of brake arms, the brake arms being rotatably supported through the rotation shafts; a pair of brake pads each arranged at one end of the corresponding brake arm, the brake pads contacting and separating from the brake wheel; and a brake part connected to another end of the brake arms, the brake part providing and releasing a braking force of the brake pads, wherein when centers of the rotation shafts are fulcrums, centers of contact of the brake pads with the brake wheel are points of action, and connections between the brake arms and the brake part are power points, the fulcrums, the points of action, and the power points are located in a semicircular area of the brake wheel.











BRIEF DESCRIPTION OF THE DRAWINGS




The other objects and features of the present invention will become apparent from the following description with reference to the accompanying drawings, wherein:





FIG. 1A

is a front view showing a first embodiment of a hoisting machine according to the present invention;





FIG. 1B

is a side view, half in section, showing the hoisting machine;





FIG. 2

is a fragmentary section showing a second embodiment of the present invention;





FIG. 3

is a view similar to

FIG. 1B

, showing a related-art hoisting machine; and





FIG. 4

is a view similar to

FIG. 1A

, showing the related-art hoisting machine.











DETAILED DESCRIPTION OF THE INVENTION




Before entering a description about the preferred embodiments of a hoisting machine according to the present invention, the elevator system disclosed in P2000-16727A is described in more detail. Referring to

FIGS. 3-4

, the elevator system comprises a support


10


arranged at an upper part of a hoistway and a hoisting machine


11


supported thereon. The hoisting machine


11


comprises a sheave


12


on which a rope is wound to support a car.




The hoisting machine


11


comprises essentially a base


13


fixed on the support


10


. Specifically, arranged on the base


13


is a stationary frame


15


having a vertical face


14


on which a stationary shaft


16


is supported in an overhang way to extend perpendicularly and then horizontally. The stationary shaft


16


includes a large-diameter portion


16




a


on the fixed-end side and a small-diameter portion


16




b


on the free-end side. A rotary frame


17


is rotatably supported on the small-diameter portion


16




b


through bearings


18


A,


18


B. The rotary frame


17


is formed like a bottomed cylinder or cup by a disk-like bottom


17




b


having a bearing holder


17




a


and a peripheral wall


17




c


arranged at the circumference of the bottom


17




b


. In order that an opening of the bottomed cylinder may approach the vertical face


14


of the stationary frame


15


, the rotary frame


17


is rotatably supported on the small-diameter portion


16




b


of the stationary shaft


16


through the bearings


18


A,


18


B.




A rotator


19


is supported at the inner periphery of the peripheral wall


17




c


of the rotary frame


17


, and a stator


20


having a radial gap with respect to the rotator


19


is fixed to the stationary frame


15


. The stator


20


is formed out of a stator core


21


and a stator winding


22


wound thereon, and is fixed to the stationary frame


15


through a bracket


23


. The rotator


19


, the stator


20


, the stationary frame


15


for supporting the stator


20


, the rotary frame


17


for supporting the rotator


19


, and the stationary shaft


16


for supporting the rotary frame


17


constitute an external-rotation type motor. The sheave


12


is fixed to the outside of the bottom


17




b


of the rotary frame


17


, and has a rope groove


12


G. A braking device


24


is arranged at the outer periphery of the rotary frame


17


, and comprises, as seen in

FIG. 4

, a pair of brake arms


25


A,


25


B having one end supported by the base


13


, a pair of brake shoes


26


A,


26


B supported by the brake arms


25


A,


25


B at the inside of the middle portion to face the outer periphery of the rotary frame


17


, a pair of brake shafts


27


A,


27


B arranged through another ends of the brake arms


25


A,


25


B to face each other, a pair of brake springs


28


A,


28


B arranged to bring the brake shafts


27


A,


27


B closer together, and an electromagnet


29


which operates to separate the brake shafts


27


A,


27


B against the brake springs


28


A,


28


B.




A tubular body


30


is arranged with the bottom


17




b


of the rotary frame


17


to be coaxial with the stationary shaft


16


. A sensor


31


is supported to enclose a slit formed in the tubular body


30


from both sides thereof, detecting the velocity of the motor.




With the above structure, the rope is moved by driving of the hoisting machine


11


through the sheave


12


to move upward and downward the car in the hoistway. Braking of the hoisting machine


11


is carried out by pressing the brake shoes


26


A,


26


B on the outer periphery of the rotary frame


17


by a pressing force of the brake springs


28


A,


28


B.




However, as shown in

FIG. 4

, the braking device


24


for the hoisting machine


11


is constructed to cover the outer periphery of the rotary frame


17


by a pair of brake arms


25


A,


25


B having one end supported by the base


13


, a pair of brake shoes


26


A,


26


B supported by the brake arms


25


A,


25


B at the inside of the middle portion to face the outer periphery of the rotary frame


17


, a pair of brake shafts


27


A,


27


B arranged through another ends of the brake arms


25


A,


25


B to face each other, a pair of brake springs


28


A,


28


B arranged to bring the brake shafts


27


A,


27


B closer together, and an electromagnet


29


which operates to separate the brake shafts


27


A,


27


B against the brake springs


28


A,


28


B, raising a problem of upsizing of the braking device


24


in the radial direction with the rotary frame


17


as center. Moreover, upsizing of the braking device


24


causes a problem of upsizing of the hoisting machine


11


provided with such braking device


24


.




Referring to

FIGS. 1A-1B

, there is shown first embodiment of the present invention. A hoisting machine


43


includes a stationary part


44


and a hollow shank


45


. A stationary frame


46


is integrally formed with an end of the shank


45


in which a rotation sensor


54


for sensing the rotational speed of the motor. A rotation-sensor adjusting cover


63


is provided to the shank


46


at an end opposite to the stationary frame


46


. A protrusion


46




a


is formed at an outer end of the stationary frame


46


to protrude in the same direction as that of the shank


45


. A motor stator


47


is arranged at the inner periphery of the protrusion


46




a


. In such a way, the shank


45


, the stationary frame


46


, and the motor stator


47


constitute stationary part


44


of the hoisting machine


43


.




The hoisting machine


43


includes a rotary part


48


. A rotary frame


49


is disposed to face the stationary frame


46


, and is rotatably supported to the shank


45


through a bearing


50


. A sheave


51


is integrally formed with the rotary frame


49


on the side opposite to the stationary frame


46


, and has a rope groove


51




a


formed at the outer periphery. A rope is wound on the rope groove


51




a


to suspend a car which moves upward and downward in a hoistway. A motor rotator


52


comprising a permanent magnet is arranged at the outer periphery of the rotary frame


49


to face the inner periphery of the motor stator


47


. Moreover, a brake wheel


53


is integrally formed with the rotary frame


49


to protrude from the outer periphery thereof. Therefore, the brake wheel


53


is larger in diameter than the rotary fame


49


and the sheave


51


. The rotary frame


49


, the sheave


51


, the motor rotator


52


, and the brake wheel


53


constitute rotary part


48


of the hoisting machine


43


.




A pair of brake arms


56


is rotatably supported to the stationary frame


46


through rotation shafts


55


, and has one end to which one end of a pair of facing brake shafts


67


is coupled. A brake spring


57


for providing a braking force is arranged around the brake shaft


67


. Another end of the brake shaft


67


is inserted in an electromagnet


58


which operates to release a braking force of the brake spring


57


. The brake shaft


67


, the brake spring


57


, and the electromagnet


58


constitute a brake part. All of the brake arms


56


, the brake shafts


67


, the brake springs


57


, and the electromagnet


58


are arranged below a horizontal center line


60


of the brake wheel


53


. Brake pads.


59


have a center line


61


positioned below the center line


60


by an angle A. Specifically, when the centers of the rotation shaft


55


are fulcrums, centers of contact “a”, “b” of the brake pads


59


with the brake wheel


53


are points of action, and connections “c”, “d” between the brake arms


56


and the brake shafts


67


are power points, the fulcrums, the points of action, and the power points are located below the center line


60


of the brake wheel


53


.




When a distance between the power points “c”, “d” is “e”, and a distance between the points of action “a”, “b” is “f”, the distance “e” is smaller than the distance “f” (e<f). Terminal boxes


62


are arranged on the stationary frame


46


at the side of the power points “c”, “d” to carry out electrical connection between the outside and the motor stator


47


and electromagnet


58


.




With the above structure, when energizing the motor stator


47


, the sheave


51


integrated with the rotary frame


49


is rotated to move upward and downward the car in the hoistway through the rope. During rotation of the sheave


51


, the electromagnet


58


is also energized to release braking by the brake springs


57


. When braking the sheave


51


, energization of the electromagnet


58


is stopped, and the brake pads


59


are pressed against the brake wheel


53


by a biasing force of the brake springs


57


.




In the first embodiment, the brake wheel


53


is separated by the horizontal center line


60


to arrange the fulcrums, the points of action, and the power points of the braking device only in the lower outer peripheral portion of the brake wheel


53


, allowing downsizing of the braking device and also the hoisting machine


43


using this device. Moreover, with the braking device, since the distance “e” between the power points “c”, “d” is smaller than the distance “f” between the points of action “a”, “b”, the brake arms


56


are disposed along the outer periphery of the brake wheel


53


, allowing further downsizing of the braking device. Further, the terminal boxes


62


for the hoisting mechanism


43


are arranged at the side of the power points “c”, “d”, i.e. at the side of the brake part of the braking device, allowing further downsizing of the hoisting mechanism


43


and easy wiring work and maintenance for the terminal boxes


62


.




The shank


45


for sustaining rotary motion, the stationary frame


46


integrated with the shank


45


, and the motor stator


47


provided to the stationary frame


46


constitute stationary part


44


of the hoisting machine


43


, whereas the rotary frame


49


rotatably supported to the shank


45


, the sheave


51


integrated with the rotary frame


49


, the brake wheel


53


integrated with the outer periphery of the rotary frame


49


and having larger diameter than that of the sheave


51


, the motor rotator


52


arranged at the outer periphery of the rotary frame


49


constitute rotary part


48


of the hoisting machine


43


. This allows simple and thin structure of the hoisting machine


43


, leading to suitable application to the elevator systems with a machine room eliminated.




Referring to

FIG. 2

, there is shown second embodiment of the present invention. A grease passage


64


is formed in the sheave


51


and the rotary frame


49


around the bearing


50


. A grease supply port


65


is provided to the grease passage


64


on the side of the sheave


51


, and a grease discharge port


66


is provided to the bearing


50


on the side of the sheave


51


. As a result, grease supply to the bearing


50


can be carried out from the side of the sheave


51


, facilitating grease supply and change.




Having described the present invention in connection with the preferred embodiments, it is noted that the present invention is not limited thereto, and various modifications and changes can be made without departing the scope of the present invention.




The entire teachings of Japanese Patent Application P2001-302050 filed Sep. 28, 2001 are incorporated hereby by reference.



Claims
  • 1. An arrangement, comprising:a rotatable brake wheel; a pair of rotation shafts; a pair of brake arms, the brake arms being rotatably supported through the rotation shafts; a pair of brake pads each arranged at one end of the corresponding brake arm, the brake pads contacting and separating from the brake wheel; a brake part connected to another end of the brake arms, the brake part providing and releasing a braking force of the brake pads; a sheave on which a rope is wound, the rope supporting an object to be supported; and a stationary part and a rotary part, the stationary part comprising a shank, a stationary frame integrally formed with the shank, and a motor rotator provided to the stationary frame, the rotary part comprising a rotary frame rotatably supported to the shank through a bearing to face the stationary frame, the sheave integrally formed with the rotary frame on the side opposite to the stationary frame, a motor rotator arranged at an outer periphery of the rotary frame to face the motor stator, and the brake wheel integrally formed with an outer periphery of the rotary frame and having larger diameter than that of the sheave, and wherein, when centers of the rotation shafts are fulcrums, centers of contact of the brake pads with the brake wheel are points of action, and connections between the brake arms and the brake part are power points, the fulcrums, the points of action, and the power points being located in a lower semicircular area of the brake wheel.
  • 2. The arrangement as claimed in claim 1, wherein a distance between the power points is smaller than a distance between the points of action.
  • 3. The arrangement as claimed in claim 1, wherein the sheave is integrally formed with the brake wheel.
  • 4. The arrangement as claimed in claim 1, further comprising terminal boxes arranged at the side of the power points, the terminal boxes carrying out electric connection to the outside.
  • 5. The arrangement as claimed in claim 1, wherein the lower semicircular area of the brake wheel corresponds to an area below a horizontal center line of the brake wheel.
  • 6. A braking device, comprising:a rotatable brake wheel; a pair of rotation shafts; a pair of brake arms, the brake arms being rotatably supported through the rotation shafts; a pair of brake pads each arranged at one end of the corresponding brake arm, the brake pads contacting and separating from the brake wheel; a brake part connected to another end of the brake arms, the brake part providing and releasing a braking force of the brake pads; a sheave on which a rope is wound, the rope supporting an object to be supported; and a stationary part and a rotary part, the stationary part comprising a shank, a stationary frame integrally formed with the shank, and a motor rotator provided to the stationary frame, the rotary part comprising a rotary frame rotatably supported to the shank through a bearing to face the stationary frame, the sheave integrally formed with the rotary frame on the side opposite to the stationary frame, a motor rotator arranged at an outer periphery of the rotary frame to face the motor stator, and the brake wheel integrally formed with an outer periphery of the rotary frame and having larger diameter than that of the sheave, wherein, when centers of the rotation shafts are fulcrums, centers of contact of the brake pads with the brake wheel are points of action, and connections between the brake arms and the brake part are power points, the fulcrums, the points of action, and the power points being located in a lower semicircular area of the brake wheel, and a distance between the power points being smaller than a distance between the points of action.
  • 7. The braking device as claimed in claim 6, wherein the lower semicircular area of the brake wheel corresponds to an area below a horizontal center line of the brake wheel.
  • 8. A hoisting machine with a braking device, the braking device comprising:a rotatable brake wheel; a pair of rotation shafts; a pair of brake anus, the brake arms being rotatably supported through the rotation shafts; a pair of brake pads each arranged at one end of the corresponding brake arm, the brake pads contacting and separating from the brake wheel; a brake part connected to another end of the brake arms, the brake part providing and releasing a braking force of the brake pads; and a stationary part and a rotary part, wherein the stationary part comprising a shank, a stationary frame integrally formed with the shank, and a motor rotator provided to the stationary frame, the rotary part comprising a rotary frame rotatably supported to the shank through a bearing to face the stationary frame, a sheave integrally formed with the rotary frame on the side opposite to the stationary frame, a motor rotator arranged at an outer periphery of the rotary frame to face the motor stator, and the brake wheel integrally formed with an outer periphery of the rotary frame and having larger diameter than that of the sheave, wherein, when centers of the rotation shafts are fulcrums, centers of contact of the brake pads with the brake wheel are points of action, and connections between the brake arms and the brake part are power points, the fulcrums, the points of action, and the power points being located in a lower semicircular area of the brake wheel, and wherein a rope is wound around the sheave, the rope supporting an object to be supported, the sheave being integrally formed with the brake wheel.
  • 9. The hoisting machine as claimed in claim 8, further comprising terminal boxes arranged at the side of the power points, the terminal boxes carrying out electric connection to the outside.
  • 10. The hoisting machine as claimed in claim 8, wherein the lower semicircular area of the brake wheel corresponds to an area below a horizontal center line of the brake wheel.
Priority Claims (1)
Number Date Country Kind
2001-302050 Sep 2001 JP
US Referenced Citations (13)
Number Name Date Kind
1255441 Larson Feb 1918 A
1314675 Lilly Sep 1919 A
1317798 Larson Oct 1919 A
2529084 King Nov 1950 A
4739969 Eckersley et al. Apr 1988 A
5153389 Nomura Oct 1992 A
5265701 Ogasawara et al. Nov 1993 A
5671912 Langford et al. Sep 1997 A
5697599 Lamb Dec 1997 A
5873434 Sugita et al. Feb 1999 A
6021872 Sevilleja et al. Feb 2000 A
6098962 Henly Aug 2000 A
6520299 Rimann et al. Feb 2003 B2
Foreign Referenced Citations (4)
Number Date Country
0 970 912 Jan 2000 EP
184790 Aug 1923 GB
6-107387 Jun 1994 JP
2000-16727 Jan 2000 JP