Implements or apparatus for applying pushing or pulling force – Multiple lifters
Patent
1980-12-11
1983-05-10
Watson, Robert C.
Implements or apparatus for applying pushing or pulling force
Multiple lifters
254104, 29429, B21D 3903
Patent
active
043825800
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a lifting and shifting apparatus in accordance with the preamble to the appended patent claim 1. The invention particularly relates to such a device for use in the erection of large cylindrical plated cisterns, the plates being arranged along a helix in the sweep, which is built up to the desired height by new plates being added at its lower end simultaneously as the sweep is shifted upwards along the helix. This method of erecting a cylindrical cistern is described inter alia in the U.S. Pat. Nos. 2,866,261 and 3,182,958. According to the first-mentioned patent specification, geared motors are used to drive the sweep upwards along the helix or screw line. According to U.S. Pat. No. 3,182,958, the upper sweep is driven with the aid of a plurality of jacks arranged between the lower edge of the upper sweep and the upper edge of the lower sweep. All these jacks lift the upper mantle simultaneously and then tip forward in the direction of the screw line, the mantle thus being rotated upwardly. The arrangement with jacks is cheaper than a plurality of geared motors, but can cause problems in the form of shock stresses at the end of each forward shift. It is further known from U.S. Pat. No. 4,078,295 to support the upper sweep with the aid of rollers in order to shift is forward along the screw line, these rollers being caused to roll in planes sloping forwards-downwards. In this case the sweep is first lifted and then rolled downwards-forwards under its own weight. The rolling movement is arrested by the upper sweep knocking against the lower one, giving rise to troublesome shocks. Alternatively, the upper sweep portion glides along the lower one with great wear as a result. Control of movement is poor.
The purpose of the present invention is primarily to avoid these disadvantages with an apparatus allowing a smooth and controlled lifting and shifting movement which is not terminated by a heavy shock and which does not cause wear as a result of any scuffing movement of the sweep edge. In accordance with the invention, this is achieved with a device having the characterizing features disclosed in the patent claim 1.
The initial lifting motion of the upper sweep is thus provided by a kind of wedge action, the sweep being maintained unmoved in the shifting direction. In accordance with a preferred embodiment of the invention, this is achieved by the track of the member which is lifted (referred to hereinafter as the lift member) sloping just sufficiently in the shifting direction so that the resultant acting on the upper body in the forward direction is less than the resistance to movement counteracting the movement of the upper body. This resistance is generated, e.g. in plated cisterns, by the friction between the bottom portion of the sweep and guide rollers which guide this portion laterally.
The shift member is preferably formed as a wedge, there being rollers arranged between coacting tracks. According to a preferred embodiment of the invention, arresting means are furthermore arranged between the shift member and the lift member and adapted for coming into action after a first phase of the shift member travel. The lift member is thus moved by the shifting mechanism of the shift member, special members providing travel for this purpose thus being dispensed with.
An embodiment of the invention is described below while referring to the accompanying drawings, where
FIG. 1 illustrates from one side and partly in section along the line I--I in FIG. 5 a lifting and shifting apparatus in accordance with the invention, mounted between the upper and lower sweeps of a cylindrical cistern under construction.
In a corresponding way,
FIGS. 2, 3 and 4 illustrate the apparatus in other operational positions.
FIG. 5 is a section along the line V--V in FIG. 1 and to a larger scale.
The support member 1 of the apparatus is hung on the upper edge 3 of the lower cistern sweep 2 and is formed as a channel-shaped frame, the web of which is formed by two horizontal spacer plates 4, each having one
REFERENCES:
patent: 2866261 (1958-12-01), Macku
patent: 3182958 (1965-05-01), Peterzon-Arbella
patent: 3774352 (1973-11-01), Weber
patent: 4067097 (1978-01-01), Okamoto
patent: 4078295 (1978-03-01), Koller
Handelsbolaget Rodoverken
Watson Robert C.
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