WO1990005897A1

WO1990005897A1 - Hydraulic balance

Info

Publication number: WO1990005897A1
Application number: PCT/IT1988/000083
Authority: WO
Inventors: Daniele Piantini
Original assignee: Lextro Line Srl
Priority date: 1988-11-23
Filing date: 1988-11-23
Publication date: 1990-05-31

Abstract

The hydraulic balance includes a chamber (34) forming a loading cell fed with liquid under pressure, an indicator (38) to measure the pressure inside the chamber (34), a cylinder (36) in which a mobile piston (32) is sliding without any appreciable friction and with a drawing interval for the liquid dripping between the wall of the cylinder (36) and the mobile piston (32) outwards owing to the pressure. Therefore, by measuring the pressure existing in the chamber (34) by means of the indicator (38), while the platform (30) is lowering, it is possible to measure the load.

Description

HYDRAULIC BALANCE

The invention object is a hydraulic bascule of a siπply execution, for πBasuring loads with reliable operation. Substantially it includes: a chamber forming a loading cell fed with liquid under pressure, a easu rer for the pressure inside the chamber, a passage between this cham¬ ber and the outer surroundings, and an organ with a mobile piston in this passage without any perceptible friction, and with an interspace where the liquid is dripping between the said passage and the above mo bile organ owing to the pressure.

The load to measure is exerting an axial push on the said piston or¬ gan contrarily to the pressure of the liquid contained in the cell, thus giving rise, in this last one, to a pressure in biunivocal rela¬ tion with the load. The measurer is active for measuring the pressure during the reentering run of the piston mobile organ when the input of the high pressure liquid to the said room stops. Means can be fores¬ een for recovering the liquid dripped outwards.

The bascule can include a guiding system with ball bearing having a longitudinal slide, to ensure mobility and guide of the above piston - 2 - organ as to said passage.

In an execution foreseen for heavy loads, the bascule can include at least three chambers and relevant organs with pistons vertica.L ly sliding along the relevant passages to support a bascule plain apt to receive the load to weith. The piston organs can be diseng_ aged frcm the said bascule pl»ain and be suitable for supporting it along'a .space on which this flat can be pushed vertically between two leaning and beating assemblies. In this execution, centering and positioning shaped profiles can be foreseen for the flat in its running with unloaded bascule towards the leaning and upper ends of the piston organs that lift it. A check directional valve can be foreseen on the feeding device for the liquid under pressu re towards the chamber or each chamber that forms the loading cell.

The invention device will be better understood by means of the de¬ scription of Table 1 which shows a a practical, not limiting exam- plification of the invention. Fig. 1 is the view of the measuring cell, whereas figures 2 and 3 show a bascule with four cells of measure in suπtnary plan. In the drawings, a bascule 30 is schematiz; ed the load which weighs on one or more pistons 32, which on the base of the load weighing on the said bascule 30, determine the pre sure inside a chamber 34 ccιrra_ιnicating with the cylinder 36 where- in the piston 32 is sliding. The pressure existing in chamber 34, which can be regenerated by means of pump P according to the loss¬ es that may occur, is measured by a device of any type 38. Between the cylinder 36 and piston 32, sliding means may be fitted for re¬ ducing friction, such as axial ball bearings. Between the cylinder 36 and piston 32, a drawing interval can be inserted from which a liquid flux is discharged owing to the load weighing from the bascu le on piston 32 and which caused a pressure in cell 34 properly filled by the pump P through a check valve 40. As scon as the out¬ weighing condition of the pushing liquid on the piston are reach- ed, the pump action is interrupted and, consequently, the liquid flows down around the piston 32 which slowly sinks down, while the pressure is stabilizing at the valute corresponding to the weight lying on the piston and can be read. Therefore, by measuring the pressure existing in the chamber 34 by means of device 38, while the bascule is lowering, it is possible to learn the load that weight on the bascule 30 and to which the pressure generated in chamber 34 is due. This chamber 34 can be in corrmunication with analogous ones by means of other stem with piston 32 when a bascu le with more weighing supports is foreseen. Bascule 30 may take a resting position le»aned on parts 42, and a lifted one against parts 44, as, when lifted, it is centered by lateral slanting profiles 46. Therefore, the load can be passed and pose without lateral stresses on pistone 32, as to which the bascule 30 is running.

The present drawing shows an exemplification given merely as a practical demonstration of the invention, since it can differ both in shapes and arrangements, however, without ccme out from the conceit of the invention.

Claims

Claims.

1) Hydraulic bascule, characterized by the fact that it includes a chamber (34) forming a loading cell fed with liquid under pressure, a measurer (38) of the pressure existing inside the chamber, a pa. sage from this chamber and the outer surroundings, and an org∑an with piston (32) which mobile in the above passage without fric¬ tion interference,- with an interval for the liquid outwards slide between the wall of the above mentioned passage and the said mobi¬ le organ outwards, due to the pressure. The load to measure per- forms an axial push on the above piston organ (32) against the li¬ quid pressure, and the mesurer (38) is active for measuring the pressure during the reentering travel of the piston (32) mobile or gan, when the liquid high-pressure feeding to the said chamber stops.

2) Hydraulic bascule, as per claim 1, characterized by the fact that means are included for recovering the outsrards percolated li_ quid.

3) Hydraulic bascule _r as per cl-aim 1 , characterized by the fact that it includes a ball bearing guide system with longitudinal slide to ensure mobility and guide of the piston organ (32) as to the above passage.

4) Hydraulic bascule, as per claim 1 , characterized by the fact that at least three chambers may be included withe the relevant piston organs, vertically movable along the relevant passages, to support a bascule plane fit for receiving the load to weigh.

5) Hydraulic bascule, as per claim 1, characterized by the fact that the piston organs (32) are disengaged from the plane and support it along a plane in which the said plane can be displac¬ ed vertically between two leaning and beating assemblies. 6) Hydraulic bascule, as per claim 1, characterized by the fact that beside including centering and positioning profiles of the planes, while running unloaded towards the leaning and upper beating assembly, a slide is possible as to the upper ends of the piston organs which lift it.

7) Hydraulic bascule, as per claim 1, characterized by the fact that it inclused a directional and check valve (40) on the feed ing device under pressure towards the.chamber, or several cham¬ bers, forming a loading cell.