A coaxial shaft system includes an inner shaft and an outer shaft. The inner shaft includes a first plurality of magnets. An outer shaft is located coaxially around at least a portion of the inner shaft. The outer shaft includes a second plurality of magnets. The second plurality of magnets faces towards the first plurality of magnets. A support system supports the inner shaft and the outer shaft so that the inner shaft does not come into physical contact with the outer shaft. A number and location of the first plurality of magnets and the second plurality of magnets are configured so that for every magnet in the first plurality of magnets there is a corresponding magnet in the second plurality of magnets that together form a closely proximate magnetically attractive pair that have opposite poles in close proximity.

A drive sprocket comprising a plurality of teeth for meshing with a drive member to transmit rotary motion, the drive member including a plurality of engagement pockets engaging the teeth of the drive sprocket, wherein each tooth has a tooth profile defined by a first side comprising a first engagement surface and an opposite second side comprising a second engagement surface, which engagement surfaces are configured such that when driven, a tooth meshes to the engagement pocket at a first contact location on the first engagement surface and also at a second contact location on the second engagement surface, wherein the first contact location is radially offset from the second contact location.

A drive sprocket comprising a plurality of teeth for meshing with a drive member to transmit rotary motion, the drive member including a plurality of engagement pockets engaging the teeth of the drive sprocket, wherein each tooth has a tooth profile defined by a first side comprising a first engagement surface and an opposite second side comprising a second engagement surface, which engagement surfaces are configured such that when driven, a tooth meshes to the engagement pocket at a first contact location on the first engagement surface and also at a second contact location on the second engagement surface, wherein the first contact location is radially offset from the second contact location.

A link chain system includes a guided endless chain having multiple links, the links having hinge axes where they join with neighboring links, the links having a length L between the respective hinge axes of the links; a chain path along which the hinge axes are guided when driven such as by a drive wheel or sprocket or by any external drive force, the chain path having no discontinuities of curvature and no discontinuities of tangency; and the chain path having a constant length in links L independent of the relative phase position of the links of chain along the path. The link chain system can include a drive sprocket or drive wheel and transition curves of the chain path to and from the drive sprocket or drive wheel and a straight-to-straight transition curve.

A link chain system includes a guided endless chain having multiple links, the links having hinge axes where they join with neighboring links, the links having a length L between the respective hinge axes of the links; a chain path along which the hinge axes are guided when driven such as by a drive wheel or sprocket or by any external drive force, the chain path having no discontinuities of curvature and no discontinuities of tangency; and the chain path having a constant length in links L independent of the relative phase position of the links of chain along the path. The link chain system can include a drive sprocket or drive wheel and transition curves of the chain path to and from the drive sprocket or drive wheel and a straight-to-straight transition curve.

Provided is a zipper chain. The zipper chain includes a plurality of chain portions arranged to face each other and engaged with each other at one point while making linear movements. Each chain portion includes a plurality of upper plates connected to each other; a plurality of lower plates arranged to respectively face the upper plates, respectively spaced apart from the upper plates, and connected to each other; a plurality of connecting portions each connecting one of the upper plates to a corresponding one of the lower plates and connecting adjacent upper plates among the plurality of upper plates or adjacent lower plates among the plurality of lower plates; and a plurality of protrusions respectively protruding from the plurality of connecting portions.

A four-hole core drilling machine of the invention includes a vertically reciprocating carriage mounted to a body, a motor coupled to the carriage, a fixing plate coupled to the carriage, to rotatably support a drive shaft of the motor, a pivoting plate fastened to the fixing plate under the condition that a pivot angle of the pivoting plate is changed, a drive pulley coupled to the drive shaft, to be rotatable by the drive shaft, four driven pulleys rotatably mounted to the pivoting plate near corners of the pivoting plate, four driven shafts rotatably mounted to the pivoting plate and coupled to the four driven pulleys, to be rotatable by the driven pulleys, a belt mounted around the drive pulley and the driven pulleys, to transmit rotation force of the drive pulley to the driven pulleys, and four core bits coupled to lower ends of the driven shafts.

Provided herein is an auxiliary hybrid system (AHS) that may be configured to provide electrical propulsion to an e.g., internal combustion-powered vehicle through the use of a battery and electric motor. Alternatively, the AHS may be configured to increase range to electric vehicles through the use of an internal combustion-powered generator. In either embodiment, the AHS is added to a vehicle without altering the operation of the vehicles' standard drivetrain, allowing the vehicle to operate conventionally when the AHS is not engaged. The AHS is compatible with a wide range of vehicles with a minimum of vehicle-specific parts.

Provided herein is an auxiliary hybrid system (AHS) that may be configured to provide electrical propulsion to an e.g., internal combustion-powered vehicle through the use of a battery and electric motor. Alternatively, the AHS may be configured to increase range to electric vehicles through the use of an internal combustion-powered generator. In either embodiment, the AHS is added to a vehicle without altering the operation of the vehicles' standard drivetrain, allowing the vehicle to operate conventionally when the AHS is not engaged. The AHS is compatible with a wide range of vehicles with a minimum of vehicle-specific parts.

A power-split hybrid transaxle uses a chain-only final drive. In addition to transferring power from the primary axis to the differential axis, the chain provides about a 2.5:1 torque multiplication. Eliminating the planetary final drive gear set traditionally associated with a chain axis transfer reduces that axial length of the transaxle and provides more space for a power take-off unit.