Joints and connections – With fluid pressure responsive component
Reexamination Certificate
1998-09-15
2001-05-15
Browne, Lynne H. (Department: 3629)
Joints and connections
With fluid pressure responsive component
C403S337000, C403S337000, C403S336000, C403S336000
Reexamination Certificate
active
06231262
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to apparatus for transmitting torque from a driving member to a driven member, more particularly to apparatus for connecting a rotatable device such as a hub to a rotatable shaft such as a motor shaft, and most particularly to a torque coupler wherein axially-exerted hydraulic pressure on opposed outer-ring conical coupler elements causes radial deformation and compression via a doubly conical inner ring with sufficient force that the shaft is gripped by the inner ring, permitting torque to be transmitted between hub and shaft.
2. Description of the Related Art
Friction couplings which rely on radial deformation of an axially-tapered ring for gripping a shaft are known in the art. For example, U.S. Pat. No. 3,569,943 issued Aug. 3, 1971 to Krauss discloses such a coupling wherein an outer ring having a conical inner bore is drawn by a plurality of screws along the mating conical outer surface of an inner ring disposed on a shaft to compress the inner ring against the shaft. Because the screws must be tightened individually, the clamping force exerted on the shaft is applied incrementally at different locations and therefore may not be uniformly distributed when the clamp is fully tightened. Further, it may be necessary to make use of inconveniently strong forces for tightening of the screws. Further, threads can degrade with repeated use, and if one screw jams then the entire assembly may be ruined. Such thread problems can be even more severe when an application requires the use of stainless steel coupler components.
U.S. Pat. No. 4,407,603 issued Oct. 4, 1983 to Lundgren discloses a similar design having a saw-tooth contour which can be formed either by a number of coaxial conical taper portions or by a helical ramp in the inner ring and a mating helical ramp in the outer ring. Again, the inner and outer rings are driven axially of each other by a plurality of screws.
A hydraulically-activated friction clamp is disclosed in U.S. Pat. No. 5,672,026 issued Sep. 30, 1997 to Disborg. The disclosed clamp comprises essentially two opposing clamps having saw-tooth helical mating means like those of Lundgren, the outer rings of the two clamps defining an annular piston and an annular cylinder and being driven apart axially by pressurized hydraulic fluid introduced therebetween. The helical mating means of each of the outer rings mates with a like helical outer surface on a radially-deformable inner ring for gripping a shaft, the outer rings being threaded by their helical surfaces onto the inner ring from opposite axial ends thereof prior to installation of the clamp onto a shaft. The length of the hydraulic stroke of the outer rings is limited to the width of the helical flights (the apparent axial length of each saw-tooth) so that the radial clamping action of the clamp is limited to the radial rise of the helix (the apparent radial height of each saw-tooth). A greater length of radial motion cannot be provided by the screw-mating means of the prior art.
Thus there is a need for a friction coupling wherein a radially-deformable inner member having a conical outer surface is readily insertable into hydraulically-displaceable outer rings without resort to screw means for insertion.
It is a principal object of the invention to provide an improved hub-to-shaft frictional coupling which meets the above objective.
It is a further object of the invention to provide an improved hub-to-shaft coupling having mechanical means for indicating visually that the coupling has been actuated to a desired extent.
It is a still further object of the invention to provide an improved hub-to-shaft coupling having first screw means for positively locking the coupling mechanically in an actuated configuration, permitting removal of hydraulic pressure, and second screw means for positively returning the coupling from an actuated configuration to a relaxed configuration.
It is a still further object of the invention to provide an improved hub-to-shaft coupling having removable means for hydraulic actuation of the coupling.
It is a still further object of the invention to provide an improved hub-to-shaft coupling wherein a central stop on the inner ring assures symmetrical retraction of the outer rings without binding during release of the coupling.
SUMMARY OF THE INVENTION
Briefly described, a frictional hub-to-shaft coupling embodying the invention includes a radially deformable inner ring which is adapted to engage by deformation along its inner bore a shaft or other concentric element such as a hub element. The outer surface of the inner ring comprises a pair of counter-directed cone surfaces which meet at substantially the longitudinal center of the inner ring. First and second outer rings surrounding the inner ring have inner races thereof formed each with a cone surface, the cones being counter directed and the surfaces mating with the conical inner ring surfaces. The two outer rings cooperate to form a sealed pressure chamber therebetween which may be filled with a hydraulic pressure medium adapted to be pressurized from an external source of pressure, whereby the outer rings are thrust apart and the inner ring is compressed thereby, clamping the shaft.
A removable input ring having a hydraulic fitting for supplying hydraulic medium to the coupler may be mounted on the first or second outer ring. Such a ring has means for mating with a hydraulic port in the outer ring to supply hydraulic medium to the clamp during actuation thereof. Means are provided for mechanically locking the outer rings in actuated configuration to permit relief of hydraulic pressure and removal of the removable ring when the coupler is fully actuated. Means are also provided for positively retracting the outer rings for decoupling, and a mechanical stop between the conical surfaces of the inner ring assures symmetrical retraction of the outer rings without binding. An index pin in one of the outer rings extends through a port in the other outer ring to permit visual monitoring of the extent of actuation.
REFERENCES:
patent: 1348434 (1920-08-01), Marshick
patent: 3009747 (1961-11-01), Pitzer
patent: 3195422 (1965-07-01), Corwin
patent: 3596943 (1971-08-01), Krauss
patent: 4364687 (1982-12-01), Adell
patent: 4407603 (1983-10-01), Lundgren
patent: 4425050 (1984-01-01), Durand
patent: 4537526 (1985-08-01), Hartl
patent: 4616948 (1986-10-01), Jelfs
patent: 4630690 (1986-12-01), Beasley et al.
patent: 4824277 (1989-04-01), Adolfsson
patent: 4878419 (1989-11-01), Vick
patent: 4979842 (1990-12-01), Miller et al.
patent: 5052843 (1991-10-01), Maurer
patent: 5476337 (1995-12-01), Mullenberg
patent: 5672026 (1997-09-01), Disborg
patent: 5947626 (1999-09-01), Miller et al.
patent: 3149067 (1982-07-01), None
patent: 3401837 (1985-07-01), None
patent: 3738138 (1989-01-01), None
patent: 19504145 (1995-08-01), None
Browne Lynne H.
Garcia Ernesto
Jaeckle Fleischmann & Mugel LLP
Riverbank Company, L.P.
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