In a transfer apparatus in which a pallet is stationary when the crossing angle between the axes of rotation of a driven roller and a driving shaft is zero, and the pallet may be driven when the angle is greater than zero, a stop-start apparatus comprising a cam follower roller supported by a support member of said driven roller, a stopper block guided and supported at a stop position of the pallet so as to move to and fro in the directions of the transfer and having a notch into which said cam follower roller fits so as to keep said angle zero, a cam the proximal end of which is pivotally supported at a forward position of said stop position having a cam surface on which said cam follower roller makes a rolling contact, a spring urging said cam to a predetermined position, the distal end of said cam, in said predetermined position, being near said notch and said cam being so shaped as to increase said angle from zero to 45 degrees from said distal end toward the proximal end.

Transfer apparatus having a pallet which is advanced along rails by a rotating shaft disposed between and parallel to the rails. The pallet has a roller frictionally engaging the shaft with its rotary axis adapted for adjustment between a position parallel to the shaft axis and a position transverse to the shaft axis such that the steeper the transverse angle, the faster the pallet is driven. The driven roller is mounted for gyratory adjustment by a lever having a forward end projecting from the pallet with a first roller to engage a stop plate on the preceding pallet which may actuate the lever to displace the roller axis towards the parallel position and thereby reduce the speed of the pallet and eventually stop the same as the pallet approaches the preceding pallet. A second roller is mounted on the lever to depend below the pallet so that it may engage a stop element fixed in the path of the second roller but out of the path of the remainder of the pallet. The pallet has one set of wheels engaging the first rail and a second set of wheels engaging a second rail. The second set of wheels, the driven roller and the lever are all mounted on a plate detachably secured to the underside of the pallet for adjustment to accommodate the pallet to the spacing between the rails.

Disclosed is an automatic carrier system having one or more self-propelled robotic carriers for carrying products-in-assembly between assembly stations of an automated assembly line. The running speed and stopping position of individual carriers is controlled by command indicators. The carriers are capable of stopping within a small distance of a desired position relative to an assembly station. Each carrier supports a pallet upon which is slidably disposed a subpallet. Each assembly station has a robotic arm upon which is located a positioning member and an assembling tool. Accurate positioning of product-in-assembly is effected by lowering the positioning member, which comprises two cylinders with tapered openings, over a pair of positioning projections mounted on the slidable subpallets. As the positioning projections slide within the tapered opening of the positioning member cylinders, the sloped surface of the tapered opening causes the positioning projections to move toward the center of the cylinders. When the positioning member reaches its lowermost point, the positioning projections are centered in the cylinders, thus causing the subpallet and workpiece to be in the desired position relative to the assembling machine.

A switching device for a transporting track on which a pallet travels supported on a cushion of air which includes a rotatable track having air jets to support the pallet and which is supported on an air bearing, a first linear motor for turning the air bearing, a second linear motor for driving and braking the pallet and a positioning device for accurately positioning the rotatable track in alignment with a fixed regular track. The switching device allows a pallet, which is supported on a cushion of air and which is driven along a fixed track by a linear motor, to be driven in a different direction by stopping the pallet on the rotatable track with a second linear motor, stopping the supply of air to the rotatable track so that the pallet is supported directly on the rotatable track, turning the air bearing and rotatable track with the first linear motor in a desired direction, accurately positioning the rotatable track with the positioner, interrupting the supply of air to the air bearing to prevent further rotation thereof, supplying air to the rotatable track to support the pallet on an air cushion and driving the pallet onto another fixed track with the second linear motor.

A lightweight car-on-track system having a pair of spaced-apart rails and an associated rotatable drive tube with a captive carrier movable along the rails and having a drive wheel in driving engagement with the rotatable drive tube. The drive wheel is spring-loaded against the rotatable drive tube and the capture of the carrier to the rails results in a controlled drive force achieved regardless of the weight of the carrier or of a load supported thereon. The system is made up of a selected number of modular units, each having adjustably mounted frame members supporting opposite ends of a rail section and a drive tube section. Adjustable mounting of frame members to an alignment plate assures alignment between rail and drive tube sections when assembling the system. A transfer device is utilized for transferring a carrier from the end of one track section to the spaced-apart end of another track section with the transfer device being oscillatable about a pivot axis. A drive tube for each track section has a generally frusto-conical end extending beyond an end thereof which coact with the drive wheel of a carrier to impart motion of a carrier onto and off the transfer device.