Abstract: A coupling in the drive train between a sewing machine motor and mechanism for driving the sewing instrumentalities of the machine is provided with resilient bumpers. The coupling is further provided with tangs which interface with the bumpers in a manner that is effective to render the spring rate of the coupling variable and reduce both vibrational effects and impact forces in the machine.

Abstract: A flexible coupling in which the torque is transmitted by elastomeric elements held in compression. The coupling includes a sleeve assembly comprised of a plurality of independent arcuate elements and a retainer ring assembly which maintain the elastomeric elements in operable contact with the blades of the hub during rotation of the coupling.

Abstract: A flexible shaft-coupling of the type having one coupling part comprising a hub with arms extending radially therefrom and a second coupling part having radial projecting portions extending between the arms separated by elastic pieces therebetween. The second coupling part comprises a plurality of similar pieces, each including a V-shaped radial projection connected to wing portions extending circumferentially from the open ends of the V. The ends of the wing portions abut each other successively and are connected to form a continuous external housing having the point of each V projecting inward and each V-shape outwardly open. A plurality of drivers affixed to the opposing shaft mate with the V-shaped openings.

Abstract: In an elastic coupling with two similar central gears assemblable on respective shaft ends and having rows of teeth, respectively, disposed adjacent one another, and a planet gear with a row of teeth having an angular pitch equal to that of the rows of teeth of the central gears, the central gears being turnable elastically resiliently so that the flanks of the teeth of the central gears form generally wedge-shaped virtual tooth gaps having a profile varying with reciprocal turning of the central gears, the teeth of the planet gear being also generally wedge-shaped and projecting into the generally wedge-shaped virtual tooth gaps, the tooth flanks of the teeth of the planet gear being in direct contacting engagement with the tooth flanks of the teeth of the central gears, and the teeth of the planet gear and the teeth of the central gears being spring-biased radially toward one another so that the teeth of the planet gear remain fully in engagement in the virtual tooth gaps.

Abstract: A torsionally elastic power transmitting device is described having respective rotatable hub and rim members coupled in torsional driving relation through resilient cushions. The improvement is directed to the radial bearing surface which is formed directly between the hub and rim members along their respective outer and inner peripheries.

Abstract: A shock-absorbing sprocket or gear assembly or like torsionally elastic device is described having resilient cushioning means interposed between mating lugs of the hub and rim to smooth and dampen torsional shocks and vibrations produced by a power drive train. An improved radial bearing surface is provided which maintains symmetry of the bearing load with respect to the drive, and which ensures concentricity between the hub and rim and keeps the rim from wobbling axially or orbiting radially with respect to the hub during operation. The cushioning means are configured relative to the hub and rim to accommodate angular displacements of at least 9.degree.. A power transmission drive system employing the shock-absorbing sprocket of the invention is also described.