Abstract: An automatic screw fastening machine embodied by the invention transmits the rotating force of a motor to a driver bit via a differential planetary mechanism consisting of an input disc, a plurality of planetary cones, a cam disc, and a variable-speed ring. The automatic screw fastening machine causes a resilient supporting unit to restrict the variable-speed ring from shifting itself in the axial direction. Furthermore, the machine is provided with a torque detection unit capable of detecting the torque of reaction force applied to the variable-speed ring by effect of the load applied to the driver bit. As soon as the detect-signal value correctly matches a specific value corresponding to the predetermined fastening torque, supply of power to the motor is discontinued. In consequence, when fully completing a screw fastening process, rotation of the driver bit is substantially reduced to zero so that no rotating force can be transmitted to the driver bit.

Abstract: An automatic screw fastening machine embodied by the invention transmits the rotating force of a motor to a driver bit via a differential planetary mechanism consisting of an input disc, a plurality of planetary cones, a cam disc, and a variable-speed ring. The automatic screw fastening machine causes a resilient supporting unit to restrict the variable-speed ring from shifting itself in the axial direction. Furthermore, the machine is provided with a torque detection unit capable of detecting the torque of reaction force applied to the variable-speed ring by effect of the load applied to the driver bit. As soon as the detect-signal value correctly matches a specific value corresponding to the predetermined fastening torque, supply of power to the motor is discontinued. In consequence, when fully completing a screw fastening process, rotation of the driver bit is substantially reduced to zero so that no rotating force can be transmitted to the driver bit.

Abstract: A pallet type conveyor including elongated frames which constitute linear pathes of pallets with continuously driven endless chains. A pallet is driven with the endless chain by the adhesive friction between rectangular attachments and adhesive friction plates. The pallet has apertures wherein adjusting bolts are respectively and rotatably secured to the pallet and mate with spring stop nuts engaged with coil springs biasing a friction plate. When the adhesive friction between the attachments and the friction plate is needed to be increased in response to a heavier workpiece carried by the pallet, a worker can remove the pallet from the frame and rotate the adjusting bolt clockwise to adjust the elasticity of the spring caused the adhesive friction in response to the workpiece.