Material or article handling – Pole or tree handlers
Patent
1995-12-19
1997-06-03
Merritt, Karen B.
Material or article handling
Pole or tree handlers
52117, B66F 1100
Patent
active
056347596
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates generally to raising and lowering columns, ie columns which comprise a relatively fixed base part and an upper part which can be raised and lowered relative to the base part. More particularly, the invention concerns apparatus for raising and lowering the columns, and a method of attaching the apparatus to the columns.
Operation of raising and lowering columns is generally performed by one or more piston and cylinder devices which is/are secured to respective attachment points on the two column parts. In locations where a large number of such columns are fitted, it is expensive to provide each column with its own individual piston and cylinder device(s). Instead, a so called counterbalance unit is employed, which is moved from column to column and on which the piston and cylinder device(s) are mounted for detachable securement to whichever column needs to be serviced/repaired. Such securement is often performed by manual lifting of the piston and cylinder device(s) into position on the column. This can be a hazardous operation, particularly where tall columns are concerned and the piston and cylinder device(s) are large and therefore heavy.
DE-A-1901659 discloses one example of such a counterbalance unit, wherein the piston and cylinder device is carried on a wheeled support. Although the support does assist in the maneuvering of the piston and cylinder into position, there is still a danger that the device will fall during the process of its attachment to the column, with a resultant risk of injury to the operative or operatives.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, this problem is obviated or mitigated by providing a disengageable mounting whereby the or each piston and cylinder device is carried by the support, the disengageable mounting being operative to permit one end of the device to be engaged with a respective attachment point on the column while the device is still carried by the support, the mounting also being operative to permit disengagement of the device from the support by subsequent operation of the device to lift it bodily relative to the support, whereby the device can then be swung to bring its other end into engagement with another attachment point on the column. Preferably, the support is in the form of a wheeled chassis. Advantageously, the disengageable mounting between the or each piston and cylinder device and the support is a disengageable pivotal mounting, and the or each piston and cylinder device is stored in a predetermined pivotal position relative to the support. Desirably, the support includes engagement means which releasably engages the or each piston and cylinder device (preferably at one end of the latter) to hold the device in its stored position. Conveniently, said one end of the or each piston and cylinder device includes an aperture, and the engagement means comprises a slot or opening in the support which is aligned with said aperture in the stored position of the piston and cylinder device, and a removable pin which extends through the slot/opening and the aperture. Preferably, the disengageable mounting comprises at least one slot in the support which engages a respective pivot pin on the or each piston and cylinder device. Advantageously, said at least one slot is angled so that the respective pivot pin cannot disengage therefrom when the or each piston and cylinder device is in its stored position.
According to a second aspect of the present invention, there is provided a method of attaching a piston and cylinder device to a raising and lowering column, the method comprising positioning in close proximity to the column a support on which the piston and cylinder device is carried by means of a disengageable mounting, operating the device to bring one end thereof into engagement with a first attachment point on one of the column parts, securing said one end of the device to the first attachment point, operating the device to move the latter bodily relative to the support
REFERENCES:
patent: 3161301 (1964-12-01), Versch
patent: 3292320 (1966-12-01), Laharty
patent: 3355847 (1967-12-01), Pratt
patent: 3362116 (1968-01-01), Erickson et al.
patent: 4020606 (1977-05-01), Pratt
patent: 5168680 (1992-12-01), Matlock
patent: 5426444 (1995-06-01), Sauter et al.
Abacus Holdings Limited
Hess Douglas
Merritt Karen B.
LandOfFree
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