Brakes – Operators – Spring
Reexamination Certificate
1999-09-17
2001-03-27
Butler, Douglas C. (Department: 3613)
Brakes
Operators
Spring
C188S00111E, C188S071700
Reexamination Certificate
active
06206149
ABSTRACT:
TECHNICAL FIELD
The invention herein resides in the art of power transmission devices such as clutches and brakes. More particularly, the invention relates to a brake for employment with steel mill cranes. Specifically, the invention relates to a caliper disk brake for steel mill cranes which is readily adapted for replacing drum brakes and improving caliper brakes employed for the same purpose
BACKGROUND ART
In parent application Ser. No. 08/789,408, U.S. Pat. No. 5,957,248, the background of the art for brakes used in association with steel mill cranes was set forth in detail. In that application, adopted fully herein by reference, there was presented in detail a caliper disk brake assembly adapted for substitution of the prior art drum-shoe brake predominantly used for crane hoist drives. It has been found that even though the caliper disk brake of the parent application provided a significant advance over the prior art drum-shoe brakes, a number of improvements can be made to the caliper disk brakes to even further enhance their operation.
It has been found that dust and other contamination may enter the magnetic armature of the prior caliper disk brake and impede full release of the brake, necessitating routine servicing or cleaning of the brake assembly. Moreover, the prior caliper disk brake has provided no visible indication of torque setting, allowing for the possibility that a brake of improper torque may be placed in an application.
It has further been found that the large mass of spring applied armature plates may cause an undesired torque spike upon brake engagement. Such a shock load may contribute to over-stressing of the shaft upon which the brake disk is mounted. Additionally, the existent caliper disk brakes have generally been quite costly to manufacture.
It has further been found that when a caliper disk brake is used on a crane travel drive, it is most desirable to have the brake applied slowly so that the load on the hoist does not swing exceptionally.
It has also been found to be quite important in the design of caliper disk brakes of the type herein that wear adjustment be easily achieved in the field.
It has further important that there be an easy way to monitor the brake wear in the field.
Yet further, it has been found that the life of the coil within the magnet body of a caliper disk brake may be adversely impacted by shock loads experienced when the crane travels over old uneven rails. Accordingly, there is a need to provide for shock absorption in the traveling mechanism.
It has further been found to be desirable to provide for multi-brake calipers on brake assemblies such that the braking operation can be imparted to the disk at uniformly spaced or diametrically opposed positions thereon.
DISCLOSURE OF INVENTION
In light of the foregoing, it is a first aspect of the invention to provide a caliper disk brake in which the armature is substantially sealed from dust and contamination.
Another aspect of the invention is the provision of a caliper disk brake in which there is a visual indication of the torque setting thereof.
Still a further aspect of the invention is the provision of a vacuum cushioned armature which substantially precludes the likelihood of torque spikes resulting from a shock load when the brakes are applied.
Still a further aspect of the invention is the provision of a caliper disk brake which allows the brakes to be applied slowly.
Still a further aspect of the invention is the provision of a caliper disk brake which is made of a cylindrical shape to maintain manufacturing efficiency, while employing an anti-rotation pin combined with an armature gap indicator to not only maintain armature registration, but allow ease of brake adjustment.
Yet an additional aspect of the invention is the provision of a caliper disk brake in which elastomeric bushings are employed to cushion the magnet assembly from travel forces.
Still a further aspect of the invention is the provision of a caliper disk brake in which at least a pair of calipers are diametrically opposed across the brake disk, improving brake force, while allowing for interchangeability between the calipers themselves.
The foregoing and other aspects of the invention which will become apparent as the detailed description proceeds are achieved by a caliper disk brake, comprising: a disk adapted for connection to a rotatable shaft; a pair of caliper arms, each having a brake pad at a first end thereof, said brake pads being maintained on opposite sides of said disk; and a magnetic actuator interposed between and connected to second ends of said caliper arms, said magnetic actuator comprising: an armature connected to a first end of said caliper arms; a magnet body maintaining an electromagnetic coil and connected to a second end of said caliper arms; and a spring interposed between and urging said armature and magnet body apart and thereby urging said brake pads into engagement with said disk.
Other aspect of the invention that will become apparent herein are achieved by a caliper disk brake, comprising: a disk adapted for connection to a rotatable shaft; a pair of brake pads maintained on opposite sides of said disk; and a magnetic actuator in operative connection with said brake pads, said magnetic actuator comprising: an armature; a magnet body in juxtaposition to said armature and maintaining an electromagnetic coil; a spring interposed between and urging said armature and magnet body apart and thereby urging said brake pads into engagement with said disk; and a pair of ring seals defining a sealed annular cavity between said armature and said magnet body, and further comprising a metered orifice communicating between ambient and said sealed cavity, said metered orifice controlling a rate of separation of said armature from said magnet body by controlled release of a vacuum therein during such separation.
REFERENCES:
patent: 1317798 (1919-10-01), Larson
patent: 3357528 (1967-12-01), Verlinda
patent: 3682279 (1972-08-01), Palme et al.
patent: 4049089 (1977-09-01), Rundle
patent: 5014828 (1991-05-01), Baldassarre
patent: 5253738 (1993-10-01), Vertesy et al.
patent: 5518087 (1996-05-01), Hwang et al.
patent: 5582277 (1996-12-01), Heidenreich et al.
patent: 5685398 (1997-11-01), Marshall et al.
patent: 5739610 (1998-04-01), Nemoto et al.
patent: 5957248 (1999-09-01), Heidenreich
Culbertson Michael O.
Heidenreich David C.
Butler Douglas C.
Power Transmission Technology, Inc.
Renner Kenner Greive Bobak Taylor & Weber
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