Abstract: In a flexible coupling generally comprising a driving and a driven hub, each having axially extending teeth, and a slotted cylindrical elastomeric element positioned around the hub teeth so as to transmit torque from a driving hub teeth to the driven hub teeth, the bottom of the slots of the elastomeric element are formed with compound curves so as to reduce stress on the elastomeric element and also provide a relief area for the outer periphery of the hub teeth to prevent engagement of the sharp edges of the hub teeth with the elastomeric element. This provides greater flexibility and improved life for the elastomeric element. Furthermore, the hub teeth are tapered in the axial direction so as to provide for axial insertion of the hub teeth into the elastomeric element and furthermore provide a curved surface on the teeth to reduce the biting effect of the leading edges of the hub teeth on the elastomeric element.

Abstract: A flexible shaft coupling of a type which uses a serpentine metal grid to connect teeth on hubs attached to driving and driven shafts has the sides of the teeth made of a polymeric resin material such as a polyurethane or a reinforced nylon 6/6, lubricated with PTFE. The side faces of the teeth deflect and deform under torque load to accommodate to the grid.

Abstract: A flexible shaft coupling of the type which uses a serpentine metal grid to connect teeth on hubs attached to driving and driven shafts has the sides of the grid rung which contact the metal teeth provided with a layer of deformable material. The layer of deformable material will deform under torque load relative to the metal teeth and metal grid and absorb differences in tooth or rung spacing or parallelism to thereby insure a more even load distribution between the rungs and teeth. A preferred deformable material is a urethane having excellent tensile strength and hardness as well as good elongation, wear resistance and flexural modulus properties.