Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Element positioned between intermeshing teeth on driving and...
Reexamination Certificate
1998-09-09
2001-06-12
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Element positioned between intermeshing teeth on driving and...
C464S076000
Reexamination Certificate
active
06244964
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a shaft coupling. More particularly this invention concerns such a coupling that permits some misalignment of the input and output axes and that also is angularly somewhat elastic.
BACKGROUND OF THE INVENTION
A standard flexible coupling has an inner member centered on and rotatable about an axis and formed with a plurality of radially outwardly projecting teeth defining a plurality of radially outwardly open pockets and each having an outer end. An outer member coaxially surrounding the inner member is centered on and rotatable about the axis and formed with a plurality of radially inwardly projecting teeth defining a plurality of radially inwardly open pockets and each having an inner end. The inwardly open pockets each confront a respective one of the outwardly open pockets and respective elastomeric bodies are each engaged in a respective one of the inner pockets and the respective outer pocket to angularly couple the members to each other.
As described in German patent document 2,630,506 of Hagin the outer ends of the inner teeth and the inner ends of the outer teeth can either overlap radially or be spaced from each other radially. When they overlap, as also described in U.S. Pat. No. 2,184,183 of Fykse, the elastomeric coupling bodies are stressed primarily in compression and it is impossible, even if the bodies are destroyed, for the members to rotate freely relative to each other, since in the absence of the coupling bodies the teeth will angularly engage each other. In the system where the outer ends of the inner teeth lie on a surface that is radially inward of the inner ends of the outer teeth, the bodies are stressed in shear and it is possible, if these bodies fail, for the two members to rotate freely relative to each other.
The main disadvantage of the system where the teeth overlap radially is that for a given rotation direction only every other coupling body is actually in use. The alternate bodies are wholly unstressed. When the teeth do not overlap, all the bodies are stressed and in use, regardless of rotation direction, but with this system in the event of overheating or some other situation that causes the bodies to fail, the coupling ceases to transmit torque at all.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved flexible coupling.
Another object is the provision of such an improved flexible coupling which overcomes the above-given disadvantages, that is which uses all the coupling bodies at all times, yet which will transmit torque even if the coupling bodies fail or are missing.
SUMMARY OF THE INVENTION
A coupling has according to the invention an inner member centered on and rotatable about an axis and formed with a plurality of radially outwardly projecting inner first teeth and at least one radially outwardly projecting second tooth together defining a plurality of radially outwardly open pockets and each having an outer end. The outer ends of the first inner teeth define an inner orbit centered on the axis. An outer member coaxially surrounding the inner member is centered on and rotatable about the axis and is formed with a plurality of radially inwardly projecting first outer teeth and at least one radially inwardly projecting second outer tooth together defining a plurality of radially inwardly open pockets and each having an inner end. The second teeth are angularly juxtaposed with each other with none of the first teeth lying angularly between the second teeth. The inwardly open pockets each confront a respective one of the outwardly open pockets. The outer ends of the first outer teeth define an outer orbit centered on the axis and spaced outward of the inner orbit. One of the second teeth projects radially across both orbits and the other of the second teeth is complementarily offset from both orbits. Respective elastomeric bodies each engaged in a respective one of the inner pockets and the respective outer pocket angularly couple the members to each other.
Thus with this system during normal operation all the elastomeric bodies transmit torque between the two members as in a standard prior-art coupling. If these bodies fail, however, the teeth will come into angular direct engagement with each other so that the coupling will continue to transmit torque. Only if the elastomeric bodies fail do the two members shift angularly enough to bring the different-length teeth into engagement with each other; otherwise the system operates like a conventional coupling, with force transmission via all of the elastomeric bodies regardless of the rotation direction.
According to the invention there are an even number of inner teeth and of outer teeth. The second teeth alternate angularly with the first teeth. In addition the inner and outer members are provided with indicia that are axially aligned when the second teeth are juxtaposed with each other. Each pocket has a steep flank and a shallow flank. The second inner teeth project radially outward through the orbits.
REFERENCES:
patent: 2125559 (1938-08-01), Hamill
patent: 2184183 (1939-12-01), Fykse
patent: 2326450 (1943-08-01), Fawick
patent: 2548839 (1951-04-01), Coombes
patent: 2696124 (1954-12-01), Flowers et al.
patent: 3237469 (1966-03-01), Berry et al.
patent: 3575015 (1971-04-01), Geisthoff
patent: 3620044 (1971-11-01), Latour
patent: 5657545 (1997-08-01), Haworth
patent: 26 30 506 (1978-01-01), None
patent: 2176335 (1973-10-01), None
patent: 2350501 (1977-12-01), None
Binda Greg
Browne Lynne H.
Centa-Artriebe Kirschey GmbH
Dubno Herbert
Wilford Andrew
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