US 6,085,501 AGranted

Automatic adjusting for lightening a machine working unit: method, device and machine

AssigneeKuhn S.A.

InventorsMartin Walch, Joel Wilhelm, Bernard Wattron, Rino Ermacora, Alain Guesdon

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Abstract

A method and device for automatically adjusting the lightening of a working unit (U) of a machine by use of a hydraulic ram (57) associated with a hydropneumatic accumulator (67). Use is made of a second hydraulic ram (58) of which the piston (53), which can move as far as a predetermined position (PP) in the cylinder (C2) and which is detached from the rod (46) of the first hydraulic ram (57), acts directly or indirectly on the latter rod via the oil (O) contained in the first hydraulic ram (57). The working unit (U) is raised and lowered by the second hydraulic ram (58). When raising the working unit (U), the volume of oil in the first hydraulic ram (57) is increased or decreased in such a way that the working unit (U) is always at a predetermined height (HP) at the end of raising travel.

Claims55

Dependent claims

Method for automatically adjusting a lightening of a working unit of a machine, which working unit is carried by a carrying structure in such a way as to rest on a ground during work and be held away from said ground when work is interrupted or during transport, said working unit being configured to be lowered so as to be brought to rest on the ground and to be raised so as to be brought away from said ground by means of at least one hydraulic-energy converter fed by an oil-supply source through a hydraulic circuit and having a first hydraulic ram equipped with a rod and associated with a hydropneumatic accumulator in which a pressure of a gas can be set initially to a value that corresponds to an amount of lightening desired for the working unit,

and having a second hydraulic ram, the working unit being raised and lowered using the second hydraulic ram of which a piston, which can move as far as a predetermined position in a cylinder of said second hydraulic ram and which is detached from the rod of the first hydraulic ram, acts on said rod via an oil contained in the first hydraulic ram, the method comprising the steps of:
raising the working unit whereby a volume of oil in the first hydraulic ram is increased only if, with the piston of the second hydraulic ram in the predetermined position, the working unit does not reach a predetermined height, and the volume of oil in the first hydraulic ram is decreased only if said working unit has reached the predetermined height, while the piston of the second hydraulic ram has not yet reached the predetermined position;
whereby the working unit is always at the predetermined height at an end of raising travel when the piston of the second hydraulic ram is in the predetermined position;
and
lowering the working unit whereby the volume of oil in the first hydraulic ram is maintained when lowering the working unit.

2 more elements

Device for automatically adjusting a lightening of a working unit of a machine, which working unit is carried by a carrying structure in such a way as to rest on a ground during work and be held away from said ground when work is interrupted or during transport, said working unit being configured to be lowered so as to be brought to rest on said ground and to be raised so as to be brought away from said ground by means of said device, said device comprising;

at least one hydraulic-energy converter fed by an oil-supply source through a hydraulic circuit and having a first hydraulic ram equipped with a rod and associated with a hydropneumatic accumulator in which a pressure of a gas can be set initially to a value that corresponds to an amount of lightening desired for the working unit;
the hydraulic-energy converter having a second hydraulic ram of which a piston, which can move as far as a predetermined position in a cylinder of said second hydraulic ram and which is detached from the rod of the first hydraulic ram, acts directly or indirectly on the rod via an oil contained in the first hydraulic ram;
said hydraulic circuit comprising a first hydraulic system coupled to the first hydraulic ram of the hydraulic-energy converter which has at least one suitable orifice for connection to the first hydraulic system,
the hydraulic circuit having a second hydraulic system coupled to the second hydraulic ram of the hydraulic-energy converter, said hydraulic-energy converter also having at least one suitable orifice for connecting the second hydraulic system;
means for increasing and decreasing the volume of oil in the first hydraulic ram at an end of raising travel of the working unit;
and
means for maintaining the volume of oil in the first hydraulic ram when the working unit is being lowered.

4 more elements

Dependencies are inferred from the claim text.