An internal combustion engine, including a pair of opposed pistons, a pair of opposed cylinders, and an output shaft, wherein each of the pistons is arranged for reciprocating motion within a respective one of the cylinders, driven by combustion, and the pistons are coupled to the output shaft by a coupling such that said reciprocating motion of the pistons drives rotation of the output shaft, wherein the coupling includes a unitary connecting rod coupled to the opposed pistons, the connecting rod having side guides for guiding a slider bearing located for reciprocating movement relative to the connecting rod, and the coupling further includes a crankshaft rotatably mounted within the slider bearing, the crankshaft having at least one guide shoulder for supporting axial location relative to the slider bearing.

An internal combustion engine, including a pair of opposed pistons, a pair of opposed cylinders, and an output shaft, wherein each of the pistons is arranged for reciprocating motion within a respective one of the cylinders, driven by combustion, and the pistons are coupled to the output shaft by a coupling such that said reciprocating motion of the pistons drives rotation of the output shaft, wherein the coupling includes a unitary connecting rod coupled to the opposed pistons, the connecting rod having side guides for guiding a slider bearing located for reciprocating movement relative to the connecting rod, and the coupling further includes a crankshaft rotatably mounted within the slider bearing, the crankshaft having at least one guide shoulder for supporting axial location relative to the slider bearing.

A stud punch includes a housing, a motor positioned within the housing, and a planetary gear train that receives torque from the motor. The stud punch also includes a punch movable between a retracted position and an extended position, and a scotch-yoke mechanism coupled between the planetary gear train and the punch. The scotch-yoke mechanism is configured to convert torque received from the planetary gear train to a reciprocating linear force, causing the punch to move between the retracted position and the extended position.

A torque drive transmission, having at least two counter-rotating cams bearing-mounted within a housing about a rotational axis. The counter-rotating cams are operative to: (i) convert a linear input to a rotary output, and (ii) drive a pair of coaxial drive shafts in opposite directions along the rotational axis. Furthermore, each counter-rotating cam defines a cam profile surface having drive and follower surfaces defining angles α and β respectively. The angles α and β are unequal to drive each cam and respective output drive shaft in an opposite rotational direction. As such, the cams may be driven in opposite directions irrespective the initial rotational position of the linear input, i.e., relative to each counter-rotating cam.

A driving mechanism for fastener driving machine, including a rotatable crank; a driving rack element rotatably installed on the crank, which comprises an engaging element, a support element and a driving rack; at least one fixed guide element. The support element and/or engaging element can move along the set trajectory. The present invention has a simple structure, a few parts and stable operation. When the crank rotates, the motion trajectory of the engaging element is straight or approximately O°, so as to reduce the kinetic friction force of load to the maximum extent, preventing wear problem, and guaranteeing constant direction of thrust on the impact unit in the course of compressed energy storage and low eccentric load in late stage, the quick release of driving mechanism is implemented, the operational stability and smoothness of impact unit are guaranteed, the work quality is upgraded.

A driving mechanism for fastener driving machine, including a rotatable crank; a driving rack element rotatably installed on the crank, which comprises an engaging element, a support element and a driving rack; at least one fixed guide element. The support element and/or engaging element can move along the set trajectory. The present invention has a simple structure, a few parts and stable operation. When the crank rotates, the motion trajectory of the engaging element is straight or approximately O°, so as to reduce the kinetic friction force of load to the maximum extent, preventing wear problem, and guaranteeing constant direction of thrust on the impact unit in the course of compressed energy storage and low eccentric load in late stage, the quick release of driving mechanism is implemented, the operational stability and smoothness of impact unit are guaranteed, the work quality is upgraded.

A drive transmission has two counter-rotating cams bearing-mounted within a housing about a rotational axis. The counter-rotating cams have asymmetrical lobe profiles which are operative to drive a corresponding pair of coaxial drive shafts in opposite directions along the rotational axis. The asymmetry of the lobe profiles prevents the cams from locking when the lobe apexes pass the top and bottom dead center positions relative to the follower or drive pins.

A drive transmission has two counter-rotating cams bearing-mounted within a housing about a rotational axis. The counter-rotating cams have asymmetrical lobe profiles which are operative to drive a corresponding pair of coaxial drive shafts in opposite directions along the rotational axis. The asymmetry of the lobe profiles prevents the cams from locking when the lobe apexes pass the top and bottom dead center positions relative to the follower or drive pins.

A lever mechanism for converting a motion from linear to rotary includes a guiding bar, a slider which slides along the guiding bar, and a lever. The lever includes a cylindrical element and a pair of slot links which are fixed frontally on the cylindrical element and between which the slider is arranged. The slider includes at least two bushes for supporting a pivot which is adapted to act on the slot links. The bushes are mutually separated by a space to accommodate a reserve of lubricant.

A power-driven reciprocating tool may include a transmission mechanism that converts rotational force from a motor to linear force to be output by a reciprocating mechanism coupled thereto, and a counterbalancing mechanism coupled to the transmission mechanism to counter-balance forces generated by the reciprocating mechanism. The transmission mechanism may include a planetary gear assembly including a sun gear in meshed engagement with at least one planet gear. In response to a force converted by and transmitted from the transmission mechanism, the reciprocating mechanism may move in a first linear direction, and the counterbalancing mechanism may move in a second linear direction, opposite the first linear direction. The opposite linear movement of the reciprocating mechanism and the counterbalancing mechanism may counteract forces generated by the reciprocating motion of the reciprocating mechanism, thus reducing vibration output by the tool.