Abstract: In a propeller shaft, a crowning portion of a male spline portion is provided in a predetermined range including a front end portion in an axial direction, and a tooth tip surface is shaped in such a manner that a tooth thickness thereof gradually increases from the front end portion toward an intermediate portion of the male spline portion in the axial direction.

Abstract: A low surface-roughness part is formed at a first tapered part, and, as a result, the roughness of an opening-edge of a groove part of an internal spline part that opens at the first tapered part is reduced, and surface pressure applied by the opening edge to a tooth of an external spline part can be reduced. As a result, the opening edge of the groove part of the internal spline part can be kept from digging into the tooth, and variation, between products, in the insertion load of a second shaft part can be suppressed.

Abstract: A gearwheel (10), in particular a parking interlock gear, includes an annular body (1). The annular body includes a first toothing (2), arranged on an outer circumference of the annular body, for engaging a locking pawl (20), and a second toothing (3), arranged on an inner circumference of the annular body, for the form-locking connection to a shaft (30).

Abstract: A steering shaft assembly comprising female shaft and a male shaft. The female shaft includes an inner surface defining a plurality of outer roller bearing tracks. The male shaft includes an outer surface defining a plurality of inner roller bearing tracks. An adaptable sleeve assembly is located between the inner surface of the female shaft and the outer surface of the male shaft and includes a body. The body defines an outer surface for contacting the inner surface of the female shaft and an inner surface for contacting the outer surface of the male shaft. The body defines at least one rib projecting radially outwardly from the outer surface of the body and projecting radially inwardly from the inner surface of the body. The at least one rib is inserted into one of the plurality of inner roller bearing tracks and one of the plurality of outer roller bearing tracks.

Abstract: A longitudinally adjustable steering shaft for a vehicle has an inner shaft received in an outer shaft to be displaceable coaxially and in the direction of a rotational axis. The two shafts have interlocking profiles in cross section for transmitting torques. A profile sleeve on which the outer shaft is telescopically arranged is arranged on the inner shaft part. The profile sleeve in a first end region surrounds a free end of the inner shaft part in the mounted state and has a radially inwardly protruding stop for abutment against an end face of the inner shaft in one axial direction and an end region of the inner shaft has a radially outwardly protruding projection for abutment of the profile sleeve in an opposite axial direction. The profile sleeve includes a radially inwardly protruding stop with reference to a simplified mounting in a first end region.

Abstract: A vehicle shaft assembly (500). The shaft assembly includes a coupling assembly having a first (506), a second (508) and a third (510) joint member. A substantially cylindrical body portion of the second joint member is drivingly connected to a first shaft (560) having an increased diameter portion. The increased diameter portion of the first shaft has a retaining member groove (604) circumferentially extending along at least a portion of an outer surface of the increased diameter portion. At least a portion of the increased diameter portion of the first shaft is drivingly connected to a crash collapse adapter (608) having a crash collapse feature circumferentially extending along an inner surface of the crash collapse adapter. A second shaft (640) is integrally connected to at least a portion of an outer surface of the crash collapse adapter (608). At least a portion of a retaining member is disposed within the retaining member groove and the crash collapse feature.

Abstract: A micro-electro-mechanical (MEMS) actuator device includes a frame, and a first functional sub-structure positioned within the frame and mechanically coupled thereto by supporting elements. The first functional sub-structure is subdivided into first and second portions. The first portion is subdivided into first and second sub-portions separated from one another by a first through trench, and the second portion is subdivided into first and second sub-portions separated from one another by a second through trench. First and second piezo-electric structures are respectively carried by the first and second sub-portions of the first portion. Third and fourth piezo-electric structures are respectively carried by the first and second sub-portions of the second portion. A third through trench extends between the frame and the first functional sub-structure except for regions in which the supporting elements are present.

Abstract: A tool device for a hand-held power tool, which can be operated such that the tool device is rotated about an output shaft of a tool-holding device, has at least one connecting device, which is detachably connected to an output shaft of the power tool. The connecting device is fastened to the tool-holding device so that a drive axis of the output shaft and a tool axis of rotation substantially coincide. The connecting device has a cut-out and at least one clamping wing, which at least partly bounds the cut-out in the radial direction of the tool axis of rotation and which is bounded substantially in the direction radial to the tool axis of rotation by a first bounding edge, which lies on a first bounding circle around the tool axis of rotation. The clamping wing extends at least substantially along a plane orthogonal to the tool axis of rotation.

Abstract: An inlay element to be arranged in a clamping region of a fiber-reinforced tube has an elongate round body, which has an outer lateral surface on which there are arranged at least two protrusions extending radially away from the lateral surface. The protrusions each have an end face remote from the round body for the areal application of an external clamping force. A tube arrangement is provided with the fiber-reinforced tube.

Abstract: The present invention relates to an improved system for coupling prefabricated construction panels.

Abstract: A spline connection structure includes a shaft portion having teeth with crowned tooth surfaces formed at equal intervals on an outer circumferential surface and a cylindrical portion having grooves into which the teeth of the shaft portion are fitted formed on an inner circumferential surface are connected. Two adjacent tooth surfaces facing each other are bent while maintaining a constant distance therebetween in a tooth width direction when viewed from a diameter direction of the shaft portion.

Abstract: A composite tube made from a combination fiber and epoxy is disclosed. The tube may be made by filament winding although other materials and processes are suitable. In one example, the tube laminate is a mix of axial and helical fibers tailored to meet the stiffness and strength requirements of the particular application. Fibers having a different modulus may also be mixed to meet axial and torsional stiffness requirements. For example, high modulus fibers may be used in a helical pattern to handle high torque loads while lower modulus fibers may be used for the remaining portion of the tube laminate. The composite tube may be used for load and/or torque bearing applications and can include a support tube pressed fit into an end of the tube.

Abstract: A rotatable assembly, such as a crankshaft or camshaft assembly, includes a first rotatable component and a second rotatable component coupled to the first rotatable component. The first rotatable component includes a first body and defines a plurality of recesses extending into the first body. The second rotatable component includes a second body and defines a plurality of protrusions extending from the second body. The protrusions are disposed inside the respective recesses to allow the second rotatable component to rotate in unison with the first rotatable component.

Abstract: A bearing device for a wheel includes a bearing. The bearing includes outer and inner members and double-row rolling elements. The bearing has a constant velocity universal joint coupled thereto in a torque transmittable manner by fitting a stem section of an outer joint member to a shaft hole of a hub wheel, in which the stem section of the outer joint member is press-fitted to the shaft hole of the hub wheel, and shapes of only the circumferential side wall portions of each of a plurality of convex portions are transferred to the shaft hole, to thereby define a convex and concave fitting portion in which close contact is achieved at an entire contact portion between the plurality of convex portions and the plurality of concave portions.

Abstract: A quick mount connector allows for easy rotation of an object, such as an antenna. The connector has a base, a coupling member and an object mount. The base is configured for connection to a surface and includes base teeth around an inner circumference. The coupling member is configured to be inserted into the base and rotates relative the base about a first axis of rotation. The coupling member has a cylindrical portion with mating teeth along its outer circumference; the mating teeth are configured to engage the base teeth. The object mount attaches to the coupling member and rotates relative the coupling member about a second axis of rotation. The object mount has a mounting plate configured for connection to the object; and a locking assembly configured to adjustably couple the coupling member to the object mount.

Abstract: A torque transmission device includes a shaft which has shaft teeth around its outer circumference, a hub which has hub teeth on an inner circumference, wherein the hub is arranged on the shaft in such a way that the shaft teeth and the hub teeth mesh with one another in order to transmit torque. The torque transmission device furthermore includes at least one spring element which passes entirely through the hub and is supported on the shaft and the hub and exerts a spring force on the hub and the shaft, wherein at least a component of the spring force is directed in such a way that around the entire circumference of the shaft and hub adjacent flanks of the shaft teeth and the hub teeth are pushed together.

Abstract: A method of forming a sliding spline-type joint using magnetic pulse forming technology includes providing a female driveshaft member and a splined insert having inwardly formed splines. A male driveshaft member is provided having outwardly formed splines engageable with the insert. A mandrel is provided having outer ribs similar to the outer spline profile of the male driveshaft member. An inductor is provided which is energized to create a pulse magnetic field. The insert is placed over the mandrel. The female driveshaft member is disposed over the insert, and both are placed inside the inductor. The inductor is energized to deform a portion of the female driveshaft member over the insert to form an array of crimps for permanently connecting the female driveshaft member with the insert. The male driveshaft member is engaged into the insert to provide a sliding spline-type of slip joint.

Abstract: A device for coupling two shafts by a gear mechanism includes a coupling part ending one of the two shafts. The coupling part is fitted concentrically into a complementary coupling part ending the other shaft. Splines of the coupling part have a constant profile along a median zone of the coupling part and which, in a first zone in continuation of the median zone, has a smaller thickness, between flanks of a spline, than a maximum thickness of the same spline in the median zone. Splines of the coupling part continue, beyond the first zone, as far as a centering zone on the same side as the first zone. The splines and the spline bottoms have, in the coupling zone between the centering zone and the first zone, a profile that continuously couples the splines and the spline bottoms to the surface of the centering zone.

Abstract: A shaft structure installed in a shaft capable of making a power-transmission, the shaft structure including: a male component having a plurality of male splines formed on an outer peripheral part thereof; and a female component having a plurality of female splines formed on an inner peripheral part thereof, the inner peripheral part configured to allow the outer peripheral part of the male component to be engaged therein so that the male component and the female component can be slidably fitted with respect to each other in an axial direction thereby making up said shaft structure, wherein the outer peripheral part of the male component and the inner peripheral part of the female component have a fabric impregnated with rubber or resin interposed therebetween.

Abstract: The invention relates to a telescopable steering spindle having an inner spindle and an outer spindle, which are arranged coaxially in relation to one another and have an out-of-round cross section for torque transmission, wherein an intermediate space is provided between the outer spindle and the inner spindle, a sliding sleeve being arranged in the said intermediate space, wherein the sliding sleeve is provided with a surface structuring on at least one surface facing the inner spindle or the outer spindle.

Abstract: A power transmission device is used to distribute torque from a power source to an external device and an auxiliary device. The power transmission device is comprised of a first bearing and a second bearing both secured to a stationary member, a first sprocket rotatably supported by the first bearing, a second sprocket capable of being drivingly coupled with the auxiliary device, a chain coupling the first sprocket with the second sprocket, a rotary shaft rotatably supported by the second bearing, which is drivingly coupled with the power source and drivingly engageable with the external device to transmit a first part of the torque to the external device, and a joint drivingly linking the rotary shaft with the first sprocket to transmit a second part of the torque to the first sprocket.

Abstract: A shaft assembly comprising a first shaft and a second shaft. The first shaft has a plurality of first splines that each have an end portion and a chamfer disposed on the end portion. The second shaft is coaxial with the first shaft and has a plurality of second splines. The plurality of second splines each have a base portion and an end portion. The end portion defines an inverted chamfer having a base and a tip. The tip projects from the base radially away from the second shaft and axially away from the base portion of the plurality of second splines. The base of the inverted chamfer undercuts the tip of the inverted chamfer. The plurality of first splines engage with the plurality of second splines to couple the first shaft and the second shaft for common rotation.

Abstract: The invention relates to a spur toothing on at least one coupling element for transmitting torques about a rotational axis, said spur toothing axially engaging with a corresponding mating cutting. The face cutting is provided with teeth from a material of the coupling element that has been plastically shaped in an at least partially non-cutting manner.

Abstract: An artificial tree having a first tree section including a trunk and a trunk electrical connector, the trunk electrical connector including a first pair of electric terminals and a second pair of electrical terminals; and a second tree section including a trunk, a trunk electrical connector, and a light string, the trunk electrical connector in electrical connection with the light string and including a first pair of electric terminals and a second pair of electrical terminals. The first tree section is configured to electrically connect to the second tree section, such that the first pairs of electrical terminals of the first and second tree sections conduct power of a first type and the second pairs of electrical connectors of the first and second tree sections conduct power of a second type.

Abstract: Apparatus is provided comprising first and second coaxial shafts, the first and second shafts extending along, and being rotatable about, a central axis. The first and second shafts are coupled together by a splined major coupling at a coupling region of the apparatus, which major coupling enables the shafts to co-rotate about the central axis. A torque element is connected to the first and second shafts, the torque element being operable to force the first and second shafts to relatively rotate about the central axis in order to apply a preload to the major coupling. The apparatus may be comprised in a gas turbine engine, whereupon the first shaft may be a fan shaft and the second shaft may be a LP turbine shaft.

Abstract: A steering arrangement includes a steering spindle and a steering coupling provided with a fork crown bearing a connecting element that connects an end of the steering spindle to the steering coupling in the form of a plug connection. To enable the combined steering spindle and steering coupling ends to be connected to each other in the correct relative position and thus to be able to prevent a defective assembly, the steering spindle end and the connecting element are coaxial plug partners on ends facing each other, by means of at least one tongue and groove guide element pair that provides a torque-transmitting priority control. The at least one groove and/or the at least one tongue of the guide element pair is molded on the interior of the shaft. A clamping device clamps the plug partners against each other in a plugging position so that they cannot come loose.

Abstract: A locking mechanism for use with a tool has a tool having a first working end, an opposite second end, a central axis therebetween, and a least one axial recess formed on an outer surface of the tool. A cap is rotatably received on the tool opposite second end, the cap comprising at least one recess formed on an outer surface thereon. The cap is rotatable between a first position in which the cap at least one recess aligns with the tool at least one recess, and a second position in which the cap at least one recess is out of alignment with the tool at least one recess. The locking mechanism further comprises a detent operatively positioned between the tool and the cap. The detent may be a pin and a spring, where the spring biases the cap into the second position.

Abstract: A coupling shaft assembly includes a coupling shaft with a first radial shoulder and a second radial shoulder, the first radial shoulder and the second radial shoulder each include at least one slot to provide a lubricant flow path.

Abstract: A drive mechanism for driving a drum, such as a mulcher drum comprises an intermediate shaft coupled to drive the drum by way of a flexible coupling. The flexible coupling may be located on an inside of a hub of the drum. A hydraulic or other motor is coupled to drive the intermediate shaft by a splined coupling. Lubrication of the splined coupling is enhanced by a supply of grease contained in a central passage within the intermediate shaft. The drive mechanism may be direct drive from a hydraulic or other suitable motor. The drive mechanism can be compact and robust against collateral damage resulting from failure of drum support bearings.

Abstract: The present invention provides a direction restricting device for the inner and outer tubes of a bicycle seat post, comprising at least one axial groove arranged on the wall of one of the tubes, and a direction restricting element fastened to the other tube at the position relative to the axial groove wall; said direction restricting element may be inserted into the axial groove and at least includes an elastic slider provided with an axial opening in the middle; the direction restricting element may be inserted into the axial groove so as to enable the axial outer walls of the direction restricting element to attach to the axial inner walls of the axial groove to eliminate the interspace between the slider and the axial groove to prevent from deflection and wobbling and to reinforce the steadiness of both tubes when the inner and outer tubes rotate relative to each other.

Abstract: A spline coupling comprises a male spline having a plurality of spline teeth separated by keyways. An insert ring comprises a plurality of U-shaped segments each having a pair of side walls separated by a gap and interconnected by a proximal end wall. Each U-shaped segment is configured to be received in one of the keyways of the male spline with the side walls being against surfaces of the keyway and the gap leaving a portion of the keyway exposed. Each U-shaped segment is connected to adjacent U-shaped segments by a distal end wall to leave a portion of the spline teeth exposed between each pair of adjacent U-shaped segments. A female spline has a shape complementary to that of a combination of the male spline and insert ring for coupling engagement therebetween.

Abstract: The present invention provides a coupling device for coupling an input shaft to an output shaft. The coupling device includes a housing having a first end and a second end. The coupling device further includes a first and second set of splines defined along the inner wall of the housing. The first set of splines is disposed near the first end and is configured for engaging splines of the input shaft. The second set of splines is disposed near the second end of the housing and is configured for engaging splines of the output shaft. The length of the first set of splines is substantially the same as the length of the second set of splines.

Abstract: A mechanical connection includes first and second components supported for rotation, the first component formed with first spline teeth, the second component formed with second spline teeth meshing with the first spline teeth, and a damper fitted in a groove formed in one of the first and second components, including an extension secured to the damper, contacting and extending between at least some of the first and second spline teeth.

Abstract: A bearing device for a wheel prevents backlash in a circumferential direction and has excellent workability for connecting a hub wheel and an outer joint member of a constant velocity universal joint. The bearing device includes a recess-projection fitting structure in which the hub wheel and a shaft section, which is fitted in a hole of the hub wheel of the outer joint member of the constant velocity universal joint, are unitized together. In the recess-projection fitting structure, entire fitting regions among projections on the outer surface of the shaft section of the outer joint member and recesses, which fit on the projections, are brought into intimate contact with each other.

Abstract: A steering shaft which is provided with a misassembly prevention structure for preventing misassembly when a shaft is inserted into and assembled with a yoke.

Abstract: A connection for transmitting rotating torque has a first component having a shaft with male spline teeth on an outer peripheral surface of the shaft. The male spline teeth extend to an inner end, and there is a blocking portion of the shaft extending in an inner direction from the inner end of the male spline teeth. A second component has a hollow portion with female spline teeth on an inner periphery of a bore. The female spline teeth extend to an outer end. Bolt holes are formed in both the hollow portion and the shaft. The bolt hole in the shaft is formed in a portion of the shaft receiving the male spline teeth. A bolt extends through the bolt holes, and the shaft is secured within the hollow portion. A distance from an inner end of the blocking portion to the inner end of the male spline teeth is greater than a distance between an outer surface on the bolt to the outer end of the female spline teeth on the hollow portion.

Abstract: In a coupling structure for coupling a shaft to a universal joint yoke, an insertion portion of a shaft is passed through an insertion hole of a universal joint yoke. An outward protrusion of a distal end portion of the shaft faces a peripheral edge of a first opening of the insertion hole across a gap in an axial direction. A fixed portion that adjoins the insertion portion is fixed to a peripheral edge of a second opening of the insertion hole by welding. An engaging portion formed on an outer periphery of the insertion portion and an engaged portion formed in an inner periphery of the universal joint yoke, which defines the insertion hole, are engageable with each other in a rotational direction with a rotation permitting gap for phase adjustment.

Abstract: A slip yoke assembly is provided. The slip yoke assembly includes a slip yoke having a long bore extending between a first end and a second end and a counterbore at the second end of the long bore. The counterbore has a first diameter and a second diameter. The first diameter is greater than a major diameter of the long bore and the second diameter is greater than the first diameter. The slip yoke assembly also includes a plug having an elastomeric member secured to a surface thereof. The elastomeric member is disposed within the first diameter and the plug is disposed within the second diameter. The plug is secured to the slip yoke by a lip formed over the plug.

Abstract: A system for efficient torque transmission, consisting of at least one driving member and at least one driven member, which uses a complementing spline profile having almost nil stress concentration which enhances the overall torque transmission capacity of a shaft with a given diameter.

Abstract: A rotating electric machine includes an inner-circumferential-side shaft, an outer-circumferential-side shaft, and a rotor. The rotor is secured to the outer-circumferential-side shaft. The inner-circumferential-side shaft is rotatably supported by a bearing that is provided between a gear and the rotor. An outer circumference of the inner-circumferential-side shaft and an inner circumference of the outer-circumferential-side shaft are spline-fitted to each other at a spline-fitted portion. The outer-circumferential-side shaft has a loosely fitted portion that is provided on the inner circumference of the outer-circumferential-side shaft and that is fitted on the outer circumference of the inner-circumferential-side shaft with a first gap having a predetermined length provided between the loosely fitted portion and the outer circumference of the inner-circumferential-side shaft.

Abstract: A spline coupling comprises a male spline having a plurality of spline teeth separated by keyways. An insert ring comprises a plurality of U-shaped segments each having a pair of side walls separated by a gap and interconnected by a proximal end wall. Each U-shaped segment is configured to be received in one of the keyways of the male spline with the side walls being against surfaces of the keyway and the gap leaving a portion of the keyway exposed. Each U-shaped segment is connected to adjacent U-shaped segments by a distal end wall to leave a portion of the spline teeth exposed between each pair of adjacent U-shaped segments. A female spline has a shape complementary to that of a combination of the male spline and insert ring for coupling engagement therebetween.

Abstract: There is provided a pillar for assembly type furniture comprising: a first pillar that has a first top to be brought in contact with the ceiling and a first bottom positioned at the opposite end to the first top; a second pillar that has a second top wider than the first bottom and a second bottom positioned at the opposite end to the second top, and has a first coupling hole in which the first pillar is inserted as much as a predetermined length, including the first bottom, longitudinally from the second top; a third pillar that is longitudinally combined with the second pillar and has a third top and a third bottom positioned at the opposite end to the third top to be brought in contact with the floor; a coupling mechanism keeping the second pillar and the third pillar longitudinally combined; and an elastic member.

Abstract: A coupling structure between a shift lever and a knob for a vehicle that includes an insert which is formed at a center thereof with an insert aperture and fixed within a knob, and of which a lower end is formed to protrude from the knob to the exterior. A shift lever rod is inserted into and coupled to the insert aperture and a skirt is formed to enclose outer peripheral surfaces of the shift lever rod and the insert. In addition, a plurality of elastic members are formed along the outer peripheral surface of the insert to protrude radially outward toward the knob by a predetermined angle and are formed to be elastically deformed and opened radially outward when the shift lever rod is coupled to the knob.

Abstract: A method for retaining lubrication in a splined joint comprises the steps of forming a seal between an inward surface of a grease seal cup and a first component, forming another seal between an outward surface of the grease seal cup and a sealing member extending from a second component, and engaging an end portion of the grease seal cup with an end portion of the first component, so that the end portion of the grease seal cup resists axial displacement of the grease seal cup during engagement of the first component with the second component. The grease seal cup of the method has a cylindrical portion integral with the end portion. The cylindrical portion has a tapered annular wall with the inward and outward surfaces. The end portion of the grease seal cup extends radially and inwardly from the cylindrical portion, so that the tapered annular wall is squeezed between the first component and the sealing member.

Abstract: A speaker mounting system comprising a speaker housing configured to house a speaker, a wall mount configured to be mechanically fastened to a wall, and one or more adjustment pieces actuatably connecting the speaker housing to the wall mount. The adjustment pieces may comprise a first adjustment piece fixed to the wall mount and a second adjustment piece slidably and rotatably attached to the first adjustment piece and pivotally attached to the speaker housing. The second adjustment piece may be configured to laterally slide toward and away from the wall mount and to rotate about a first axis and the speaker housing may be configured to rotate or pivot relative to the second adjustment piece about a second axis perpendicular to the first axis. The speaker mounting system may also comprise a biasing member and locking mechanism for selectively allowing and preventing rotation about the first and second axes.

Abstract: A motor vehicle 10 includes a hydromechanical powersplit transmission 11 having a hydraulic pump motor unit drive shaft 44 and a gear 76. The shaft 44 and gear 76 are drivingly connected together with a spline connection 160. The spline connection 160 includes an internal spline connector 161 and an external spline connector 162. Each spline connector 161, 162 includes a spline portion 166, 174 and a generally smooth portion 168, 175 adjacent its spline portion. During assembly, generally smooth portion 168 of the internal spline connector 160 engages and guides spline portion 174 of the external spline connector 162 to longitudinally and circumferentially align the spline portions 174 and 166. After assembly, the spline portions 166, 174 and the generally smooth portions 168 and 175 are radially aligned with and engage one another to form a rigid driving connection.

Abstract: A driveshaft mechanism including a driveshaft insert and a driveshaft are provided. The driveshaft insert is coupled to the driveshaft. The driveshaft insert is configured to couple with a component such that the driveshaft and the component rotate together.

Abstract: A spline structure, in the form of an aeronautical brake drive bar, has wheel attachment points at its ends for engaging a wheel rim. Each wheel carries a regularly spaced series of these drive bars for engaging friction discs carried by the wheel hub. The main body of each brake drive bar is formed from titanium internally reinforced by composite blocks each comprising a bundle of silicon carbide fibers contained in a matrix that is diffusion bonded within the main body. Other spline structures can be formed in a similar manner.

Abstract: A system includes a rotary machine. The rotary machine has a spline joint coupling first and second rotary components. The spline joint has a male spline portion and a female spline portion. The male spline portion includes a first plurality of spline teeth spaced circumferentially apart from one another about a longitudinal axis of the spline joint. The female spline portion includes a second plurality of spline teeth spaced circumferentially apart from one another about the longitudinal axis of the spline joint. The first plurality of spline teeth and the second plurality of spline teeth extend axially along the longitudinal axis. At least one tooth of the first or second plurality of spline teeth has at least one groove extending crosswise relative to the longitudinal axis. The at least one groove is disposed at an intermediate axial position between opposite axial ends of the at least one tooth.

Abstract: A connection between a shaft and a coupling that preferably involves involute shaped splines is designed to reduce stress from torque applied to the shaft by a drive motor. To avoid stress concentration at the mouth of the coupling on startup, the shaft splines are made to taper from the shaft end down to the spline end. As a result, the initial contact with the coupling splines occurs within the coupling and removed from it mouth. The shaft is allowed to elastically twist in response to the applied torque as the contact area increases with shaft twisting and the contact line moves toward the mouth of the coupling. Some shaft elastic twist occurs without adding stress to the shaft splines until coupling contact is made.