FR2504487A1 - Dynamometer arrangement for semi-submersible platform - has pulley measuring tractive force on chain and elongated element fixed to shaft supported by dynamometer measuring cell - Google Patents

Abstract

A pulley (1) with its axle horizontal, has a chain running in its groove. The pulley is fixed to a pinion (2) driven by a motor and reduction gear driving an output pinion (3). The pulley and pinion assembly are free to rotate on the axle (4) which has protrusions (5) at each end eccentric to the shaft and on which the shaft rests. These are mounted in firm supports on the hoist assembly (6). An elongated part (7) fixed to the shaft is supported on a dynamometric measuring cell (8) fixed to the frame of the hoist, and measures all the forces on the shaft which include traction, friction, drive and braking forces.

Description

BARBOTIN GUINDEAU ALLOWING FORCE MEASUREMENT
OF TRACTION EXERCISED BY A CHAIN
The present invention relates to a gypsy windlass for measuring the vertical tensile force exerted by a chain meshing in the gypsy.

Such a windlass can be used in particular for anchoring so-called semi-submersible sea platforms for which the traction exerted by the chain must always be known.

Several solutions currently exist to solve the problem posed by measuring this force.

According to a first measurement mode, the windlass support is fixed to the platform by means of a pivot at one of its ends while the other end rests on a measurement cell.

According to another measurement mode, the chain passes through an auxiliary sheave whose axis rests on one or more measurement cells. However, in this case, the passage of the chain links in the groove of this sheave generates significant transient tensile forces for the chain since the latter is not like a rope, a continuous object.

The object of the present invention is to overcome these drawbacks by means of a gypsy windlass making it possible to measure the tensile force exerted by the chain both when the gypsy is rotated by one or more sprockets and when is braked for example by a band brake or that it is stopped by means of a latch.

According to the invention, the gypsy which is either secured to a pinion driven by a geared motor assembly, or braked by means of a band brake, or stopped at
by means of a latch, is free to rotate around
his tree.

The sprocket shaft has respectively at each of its ends two projections of the same axis eccentric with respect to that of the shaft and resting on bearings integral with the support of the windlass. This shaft is integral with an elongated part bearing on a measuring cell forming a stop, and thus preventing the shaft from rotating with the gypsy.

The invention will be better understood and other objects, advantages and characteristics thereof will appear more clearly on reading the following description to which a plate of drawings is annexed.

Figure 1 shows schematically, seen from above, the windlass according to the invention, and Figure 2 illustrates the method of measuring the tensile force.

Referring now to the figures, the windlass comprises a gypsy 1 with a horizontal axis, in the groove of which the chain not shown in the figure meshes.

In the example shown, the gypsy 1 is integral with a pinion 2 driven by a geared motor assembly of which only the output pinion 3 is shown.

The gypsy 1 and the pinion 2 are free to rotate about their horizontal shaft 4. The latter is provided, at each of its ends, with a projection 5.

The two projections 5 are of the same eccentric axis relative to that of the shaft 4 which rests, via these projections, on bearings integral with the support 6 of the windlass. An elongated piece 7 is secured to the shaft 4 and is supported on a measuring cell, for example a dynamometer 8, judiciously arranged and secured to the windlass frame. This cell 8 acts as a stop.

The measurement method is then extremely simple with such a device. All the forces at play, traction exerted by the chain and friction on the one hand, motor, brake or stopper on the other hand, are applied to the shaft 4, and their result is shown diagrammatically by the arrow 9, FIG. 2. L 'shaft 4 tends to rotate around the projections 5 which rest on bearings integral with the frame 6, and the piece 7 of elongated shape, integral with the shaft 4, presses on the measuring cell 8 with a force proportional to the resulting force shown schematically by the arrow 9.

 The measuring cell 8 can be of any known type, in particular a load cell based on strain gauges or a hydraulic load cell.

Although only one embodiment of the invention has been described, it is obvious that any modification made by the man on the part in the same spirit would not depart from the scope of the present invention.

Claims (1)

 SINGLE CLAIM  Gypsy windlass allowing the se "ve vertical pulling force exerted by grenant in the said gypsy, the latter being free oe rotation around its shaft and being, either integral with a pinion driven by a motor-reduction unit, or braked at by means of a band brake, or stopped by means of a latch, characterized in that the shaft (4) of said gypsy (i) has respectively at each of its ends two projections (5) of the same axis offset relative to to that of said shaft and resting on links integral with the support (6) of said gypsy (1), said shaft (4) being integral with an elongated piece (7) bearing on a measuring cell (6) .