Abstract: An extendible multi-frame stand includes at least three frames arranged in a telescoping relationship, having a single coherent alignment and locking mechanism which includes alignment means for preventing relative rotation between the first and second frames, alignment means for preventing relative rotation between the second and third frames, means for locking the second and third frames at the limits of their longitudinal extension positions, and cam-operated releasable locking means for controlling extension and retraction of the second and third frames relative to each other and to the first frame.

Abstract: A two-part jack system includes a mechanical jack stand with a ratchet mechanism and a ratchet release, and a power unit that may be selectively aligned with and attached to the jack stand for raising or lowering it. A unitary control mechanism carried by the power unit selectively locks the power unit in an aligned position relative to the jack stand, and also selectively releases the ratchet release of the jack stand. A locking mechanism is carried in part by the jack stand and in part by the power unit. The unitary control mechanism has three different operating positions. In one operating position the locking mechanism is kept locked while the ratchet release is left in an unreleased state; in a second operating position the locking mechanism is kept locked while the ratchet release is released; and in the third operating position the locking mechanism is held in an unlocked condition while the ratchet release is left in an unreleased state.

Abstract: An extendible jacking apparatus including first, second and third normally vertical frames arranged in telescoping relationship, and containing a locking mechanism for automatically locking the first and second frames together while the third frame is being raised, locking the second and third frames together when the third frame is fully raised, and unlocking the first and second frames to allow extension of the second frame. Conversely, the locking mechanism is automatically reversible as the jack is lowered, unlocking the second and third frames and relocking the first and second frames upon the second frame being fully retracted into the first, allowing the third frame to allow be fully retracted into the first and second frames.

Abstract: A hydraulic power unit for a two-part jack system, having lifting arms which are raised or extended by means of hydraulic power whenever an associated jack stand is to be either raised or extended. The necessary hydraulic pressure is generated manually, by use of a hand pump. The power unit includes a single release valve which operates automatically as an excess-pressure bleed-off valve whenever the hydraulic cylinder pressure exceeds design capacity, and is also adapted to be controlled manually from the handle of the power unit for unloading total hydraulic pressure whenever the lifting arms are to be lowered. The release valve and all of its associated mechanisms are mounted in or on a single metallic block which is very easily manufacturable.

Abstract: A two-part jack system includes a mechanical jack stand with a ratchet mechanism and a ratchet release, and a power unit that may be selectively aligned with and attached to the jack stand for raising or lowering it. A unitary control mechanism carried by the power unit is adapted to selectively lock the power unit in an aligned position relative to the jack stand, and also to selectively release the ratchet release of the jack stand. A locking mechanism is carried in part by the jack stand and in part by the power unit. The unitary control mechanism has three different operating positions. In one operating position the locking mechanism is kept locked while the ratchet release is left in an unreleased state; in a second operating position the locking mechanism is kept locked while the ratchet release is released; and in the third operating position the locking mechanism is held in an unlocked condition while the ratchet release is left in an unreleased state.

Abstract: In an exemplary embodiment in a two-part jack system which includes a jack stand having a load-bearing member supported from vertically telescoping members, one of which has ratchet teeth and another of which carries a spring-loaded pawl for selectively engaging the ratchet teeth, and a power unit having arms for directly supporting the load-bearing member in order to extend or retract the jack stand, the invention is directed to an automatic release mechanism operable when the power unit is being utilized to retract the jack stand for disengaging the pawl from the ratchet to thereby permit complete retraction of the jack stand in a single movement and comprises: an extension arm on the pawl; a pusher member carried on the power unit for selectively engaging the extension arm so as to cause the pawl to disengage from the ratchet teeth; spring means urging the pusher member towards the extension arm; means coupled to the pusher member for selectively restraining its movement; and restraining means being adapte

Abstract: A system of jacking apparatus includes an extendible jack stand with a ratchet for latching it in an extended position, and a power unit which can be selectively engaged with or disengaged from the jack stand. The power unit includes a screw-driven scissors which is interposed between upper and lower plates of the jack stand for raising the jack stand.The jack stand has a ratchet plate whose lower end protrudes in an exposed location where it can be engaged by a ratchet release member in the power unit.The power unit is also independently usable as a jack, having a pivotally supported flip-top cover which can be placed over the top of the scissors for engaging and supporting a load.

Abstract: A system of jacking apparatus includes an extendible jack stand with a ratchet for latching it in an extended position, and a power unit which can be selectively engaged with or disengaged from the jack stand. The power unit includes a screw-driven scissors which is interposed between upper and lower plates of the jack stand for raising the jack stand.The jack stand has a ratchet plate whose lower end protrudes in an exposed location where it can be engaged by a ratchet release member in the power unit.The power unit is also independently usable as a jack, having a pivotally supported flip-top cover which can be placed over the top of the scissors for engaging and supporting a load.

Abstract: A plurality of extendible jack stands are used in conjunction with, and their operation controlled by, a single power unit. The power unit transports an individual jack stand, positions it underneath a load, and raises or extends it. The jack stand is then locked in its extended position, and the power unit is detached from that jack stand and is then used for transporting, positioning, and raising another jack stand. When the load is to be lowered, the power unit controls the unlocking, lowering, and retraction of the jack stands, one at a time. In this manner a number of jack stands may be placed underneath a load, the load raised, the load later lowered, and the jack stands removed, without any need for the operator himself to place his body underneath the load.

Abstract: A mobile power unit for a jacking system having extendible members is disclosed. The unit includes a frame having a pair of lifting members each having an extension member mounted therein and a pair of tie-rods each connected between the frame and the extension members to move the extension members progressively forward as the lifting members are raised. A pair of guides each having a slot are mounted on each of the lifting members to maintain the top of a jack stand at a constant angular relation with the extension members. The device also includes an alignment mechanism having a pair of curved springs each mounted on one of two arms of the frame and a pair of associated protuberances each mounted on opposite parallel walls of the jack stand to align the jack stand at a predetermined location on the frame. A release mechanism for releasing the jack stand has two cams each mounted on one of the two arms of the frame and a pair of pins each mounted to extend outwardly from opposite ends of the jack stand.

Abstract: An extendible jack stand for a jacking system which includes a wheeled hydraulic power unit having an operating handle, and at least two extendible jack stands which are identical. Each jack stand is adapted to rest upon the ground, and the power unit can be wheeled into (or out of) engagement with the jack stand. When engaged with a jack stand the power unit is capable of extending (or raising) the jack stand; a ratchet on the jack stand then locks it in its extended position. A manual control on the power unit is coupled to the jack stand (when the two units are interengaged) for releasing the ratchet, so that the power unit can then lower the jack stand to its retracted position.

Abstract: A jacking system includes a wheeled hydraulic power unit having an operating handle, and at least two extendible jack units which are identical.Each jack unit is adapted to rest upon the ground, and the power unit can be wheeled into (or out of) engagement with the jack unit. When engaged with a jack unit, the power unit is capable of extending (or raising) the jack unit; a ratchet on the jack unit then locks it in its extended position. A manual control on the power unit is coupled to the jack unit (when the two units are interengaged) for releasing the ratchet, so that the power unit can then lower the jack stand to its retracted position.

Abstract: A jacking system includes a wheeled hydraulic power unit having an operating handle, and at least two extendable jack units which are identical.Each jack unit is adapted to rest upon the ground, and the power unit can be wheeled into (or out of) engagement with the jack unit. When engaged with a jack unit, the power unit is capable of extending (or raising) the jack unit; a ratchet on the jack unit then locks it in its extended position. A manual control on the power unit is coupled to the jack unit (when the two units are interengaged) for releasing the ratchet, so that the power unit can then lower the jack stand to its retracted position.