Implements or apparatus for applying pushing or pulling force – Single throw lever – Mechanically actuated
Patent
1992-01-10
1992-10-27
Swann, J. J.
Implements or apparatus for applying pushing or pulling force
Single throw lever
Mechanically actuated
254DIG4, B66F 300
Patent
active
051582660
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention concerns a jack with a single leg, with a lifting arm that pivots around a stationary horizontal axis on the leg, with a threaded shaft that is articulated to the leg and engages the lifting arm either directly or by way of lever arms articulated to the leg, and with a manually operated crank that has non-rotationally secured to its end a claw that has a transverse slot and sides that can be employed to attach the claw to a transverse bolt on the end of the shaft loosely enough to allow the crank to activate the shaft even when it is not aligned with it.
Providing a jack, especially a scissoring jack or a two-point articulation jack of the scissoring type, with a detachable crank to overcome the unavoidable distance between the jack and its user is generally known. Using a slip-over polygon to attach such a crank is also generally known. Alternatively, providing the shaft of such a jack with an eye and the crank with a hook that hooks into the eye and entrains the shaft when the crank is rotated is known.
A jack with the aforesaid characteristics is known from German GM 8 701 736. The claw has an open slot that is longitudinal and hence parallel to the shaft of the crank. The slot fits over one end of a transverse bolt. The other side of the claw has another slot that slides over the bolt. The slots in the two sides fit loosely enough over the bolt to allow use of the crank even when its shaft is not aligned with the threaded shaft. The crank will accordingly not separate unintendedly from the jack. It has, however, been discovered that this mode of attachment is not evident or at least not obvious to an uninstructed user.
SUMMARY OF THE INVENTION
The object of the present invention is accordingly to improve a jack of the aforesaid type to the extent that even an uninstructed user will fully comprehend how to attach the crank to the threaded shaft such that they will not unintendedly separate to the greatest extent possible.
This object is attained in that the transverse slot in the claw slides over the transverse bolt and, at the end of the side of the claw, has a width no greater than the diameter of the bolt, that the claw fits loosely enough around the bolt to allow it to rotate, and in that the sides of the claw have prongs that loosely surround the threaded shaft.
It is significant to the invention that the transverse slot demarcated by the two sides of the claw is exploited for attaching the crank to the threaded shaft with the claw. The attachment is established just by fitting the two parts together and, since it constitutes the only possibility of obtaining a rotating connection between the crank and the jack, even an uninstructed user cannot be misled. It is also of significance that the transverse slot is no wider than the transverse bolt is thick. Due to the comparatively more extensive distance between the sides of the claw behind the slot in conjunction with the dimensions of the transverse slot, any rotation of the crank in relation to the threaded shaft will prevent the two parts from separating. It is, finally, also of significance that the sides of the claw surround the threaded shaft loosely, so that, when the crank tilts out of alignment with the shaft, it will not be impeded from rotating.
Claws with the aforesaid properties are also simple and inexpensive.
It is of particular advantage for the sides of the claw to be approximately at a distance apart that is twice the width of the transverse slot and to have prongs that bend toward one another. Such a dimension will allow the transverse bolt to rotate to a considerable extent in relation to the sides of the claw and even more reliably prevent the crank from separating unintendedly from the threaded shaft. The bending toward one another of the prongs is a simple means of ensuring that the threaded shaft will rotate far enough in relation to the claw.
Since the threaded shaft is thicker than the transverse slot is wide and the transverse bolt is thinner than the threaded shaft, the claw and
REFERENCES:
patent: 2560797 (1951-07-01), Humphreys
patent: 2587067 (1952-02-01), Sachtleber
patent: 2758816 (1956-08-01), Pickard et al.
patent: 3857548 (1974-12-01), Takeuchi
patent: 4583713 (1986-04-01), Fukura et al.
patent: 4765595 (1988-08-01), Alten
August Bilstein GmbH & Co. KG
Fogiel Max
Swann J. J.
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