Abstract: A hand truck convertible between forward and sideways displacement has wheels individually disengageable from the hand truck frame for mounting to the frame in either a mutually parallel wheel position or a mutually in-line wheel position transverse to the parallel wheel position. An optional wheel base extension can be installed for in-line mounting of more than two wheels. Other options include a retractable stand for supporting the loaded hand truck in upright position and an auxiliary load carrying shelf. The hand truck and one or more of the optional accessories may be sold as a kit of parts.

Abstract: A hand truck convertible between forward and sideways displacement has wheels individually disengageable from the hand truck frame for mounting to the frame in either a mutually parallel wheel position or a mutually in-line wheel position transverse to the parallel wheel position. An optional wheel base extension can be installed for in-line mounting of more than two wheels. Other options include a retractable stand for supporting the loaded hand truck in upright position and an auxiliary load carrying shelf. The hand truck and one or more of the optional accessories may be sold as a kit of parts.

Abstract: An apparatus is provided for operating a segmented sliding overhead door. The door is of the type for sliding in a pair of side tracks mounted at either side of the door between a dosed vertical position and an open horizontal position. A driver is mounted at the side-to-side center of the door and extends away from an interior side of the door. The driver includes a screw drive shaft adapted to be mounted horizontally above the door. A motor is engaged with the drive shaft and provides reversible rotational drive force to the drive shaft. A drive shaft coupling unit engages the drive shaft for moving along the drive shaft in response to rotation of the drive shaft. A track assembly engages and supports the rotating drive shaft and guides the coupling unit in linear travel along the drive shaft. A door connecting rod assembly serves to rigidly jam the door against the floor when the door is in the fully closed position, and connects the carrier unit to the door for moving the door along the side tracks.

Abstract: A mechanical drive for transporting a load attached to a load carrier element displaceable along a rotary threaded shaft between unthreaded ends of the shaft features precision end-of-travel positioning of the load and is improved to eliminate vibration of the load carrier element against the end of the thread on the rotating shaft thereby reducing wear of both the thread end and the load carrier.

Abstract: A linear mechanical drive with precise end of travel load positioning includes a drive shaft having a threaded portion intermediate two non-threaded portions, reversible motor drive turning the shaft, a load carrier element threaded on the shaft for pulling the load along the shaft, the carrier disengaging at the non-threaded portions thereby to precisely determine the end position of the carrier irrespective of continued drive shaft rotation. The carrier reengages to the threaded portion upon reversal of drive shaft rotation, and a load connector on the carrier element is adjustable for precisely positioning the load at one or both of the end of travel positions. Other features disclosed protect the drive against excessive mechanical wear and disengage the load from the carrier element for strain relief.

Abstract: This invention is directed to a valve drive means for a vertical up-down valve of the type having a valve shaft linearly movable within a cylindrical valve bore between a first, normal, valve position and a second, occasional valve position. The drive means includes a vertical rotatable drive shaft with a threaded portion formed between non-threaded portions and a mateably threaded coupler for engaging the drive shaft and transmitting axial force to the valve shaft. The movement of the valve shaft is precisely limited by disengagement of the coupler from said threaded drive shaft portion irrespective of continued rotation of said drive shaft. Means are included for neutralizing hydraulic pressure which would interfere with re-engagement of the coupler with the threading on the drive shaft. Means are also preferably provided for deriving a torque component for rotating said valve shaft within said bore and thus facilitating any "freezing" of seal rings mounted to said valve shaft within said valve bore.