FR2468892A1 - Weighing instrument with self contained dynamometer - has lever system with auxiliary pivots to change weighing ranges - Google Patents

Abstract

The appts. comprises an enclosure which is fixed to a load support by screws. A base in the enclosure is attached to the load support by these screws. Four horizontal lever arms, which are joined by communicating links, are coupled via a lower link to a shaft from the load support. The last arm has a knife edge located on a vertical column. On the end of this arm is mounted a blade connected to the dynamometer shaft. The dynamometer is mounted in a hood fixed to the column. Supplementary knife edges allow the lever ratios to be changed for the dynamometer range. The dynamometer and lever are enclosed to prevent inadvertent damage, and the knife edge portions are adjustable to allow the instrument to adapt to any load condition.

Description

 The invention relates to a weighing instrument with associated dynamometer.

It is known that such instruments are used to measure the quantity of material by continuous or discontinuous summation of the force exerted by the material on a load receptor, for example a roller on which a conveyor belt circulates.

 The weighing instrument according to the invention is characterized in that it comprises a box containing on the one hand said dynamometer which is vertically drawn and on the other hand a system of reduction levers comprising a series of lever arms as well as '' a system of support columns, each lever arm comprising a knife placed on a support column, a knife connected to a knife of the next arm by a communicator if it is not the last arm in the series and a knife connected to the previous arm by a communicator if it is not the first arm in the series, the first arm in the series comprising a knife which can be connected to a pull rod coming from the load support which slides through an opening in the box, the last arm can be connected to the dynamometer rod.

 Thus the weighing instrument being inside a box is sheltered from the weather. According to an important characteristic of the weighing instrument according to the invention - the knives connected by the communicators can be positioned at several points on the arms. Thus it is possible to adjust the gear ratio and to adapt the weighing instrument to several types of load balancers with a vertical pull.

- To allow greater freedom to adjust the gear ratio, the arms are provided from the second arm of the series with an additional knife aligned with the pull rod which can be connected to the end of the draw rod.

 Finally, to allow the instrument to be calibrated without dismantling, means are provided inside the box to apply a standard weight to the last arm.

 The present invention will be better understood in the light of the description which will follow in which, - Figure 1 shows in vertical section the weighing instrument according to the invention, - Figure 2 shows a horizontal section of the weighing instrument weighing according to the invention, - Figures 3 to 6 show diagrams of the lever arms of the weighing instrument according to the invention - Figure 7 shows a detailed view of a lever arm provided with knives adjustable in position, - Figures 8 and 9 show the device for calibrating the weighing instrument.

 Figure 1 shows a section through the weighing instrument according to the invention. This instrument comprises a box 1 which can be fixed above a load support 2 by screws 3.

This box includes a horizontal base 4 located at the base of box 1 and connected to the load support by the screws 3 passing through the bottom 5 of box 1.

The bottom 5 serves as a support for the 3 setting screws 6 (see FIG. 2) which ensure perfect horizontality of the base 4. The base 4 is provided with 3 columns 7, 8 and 9 for supporting the lever arms which are vertical.

The instrument according to the invention comprises 4 horizontal lever arms 10, 10 ', 10 "and 10"'.

 The first arm 10 comprises a first knife 11 supported on the column 7, a second knife 12 connected to a third knife 13 'of the arm 10' by a communicator 14 and a third knife 13 connected by a communicator 15 to the end of a vertical pull rod 16 coming from the load support.

 This pulling rod 16 passes through an opening 17 formed in the bottom 5 of the box 1.

 The second arm 10 'comprises a first knife 11' supported on the column 8 and a second knife 12 'connected by a communicator 18 to a third knife 13 "of the third arm 10".

 The third arm 10 "comprises a first knife 11" supported on the column 7 and a second knife 12 "connected by a communicator 19 to the knife 13" 'of the last arm 10 "'.

This last arm 10 "'or sensitive arm comprises a knife 11"' situated towards the middle and placed on the column 9.

 On the end 12 "'of the arm 10"' is mounted a blade connected to the rod 21 of the dynamometer 22.

This dynamometer 22 is mounted in a cover 23 fixed to the column 9.

On the arms 10 ', 10 "and 10"' you can attach an additional knife 24 ', 24 ", 24"'.

These additional knives are aligned with the draw rod 16.

Thus, the communicator 15 can be hung on the knife 13 or on the knives 24 ', 24 "or 24"', which changes the gear reduction ratio. Referring to the diagrams of Figures 3 to 6 we find the four cases, depending on whether the communicator 15 is hooked to the knife 24 "'(use of the only sensitive arm 10"', Figure 3) to the knife 24 "(use of the last two arms 10 "and 10n ', figure 4) with a knife 24' (use of the last 3 arms 10 ', 10" and 10 "', figure 5) or knife 13 (use of the 4 arms, figure 6).

Thus when f is the maximum normal value of the vertical pull dynamometer, it is possible to measure with the only sensitive arm (FIG. 3) a force applied to the load support of n f.

We can measure forces n1f (figure 4), n2f (figure 5) and n3f (figure 6).

 8 positions 25 "'and 25" are provided on the sensitive arm 10 "' and on the arm 10" on which the knives 13 "'and 12" can be fixed connected by the communicator 19.

On each of the arms 10 and 10 ′, two positions 26 and 26 ′ are provided opposite, on which the knives 12 and 13 ′ can be mounted connected by the communicator 14.

 On each of the arms 10 ′ and 10 ″ there are provided 2 opposite positions 27 ′ and 27 ″ on which the knives 12 ′ and 13 ″ can be mounted connected by the communicator 18.

In FIG. 7 is shown in more detail the arm 10 "provided, on the one hand with the 8 positions 25" on which can be fixed the knife 12 "connected by the communicator 19 to the knife 13" of the arm 10 "'and , on the other hand, of the 2 positions 27 "on which the knife 13" can be fixed connected by the communicator 18 to the knife 12 'of the arm 10'.

 The third knife 11 "from the lever 10" was hooked to the support column 7 by means of a communicator 28.

By changing the various knives, the weighing instrument can be adapted to the load receptor and to several types of dynamometers used, the draft of which is vertical.
The sensitive arm 10 "'is provided, at its end opposite to the dynamometer, with a special knife 29. A micromotor 30 with 2 directions of travel is mounted on the column 7.

This micromotor 30 is provided with an arm 31 which, when raised, suspends a standard weight 32 above the knife 29 (FIG. 8) and, when lowered, leaves the standard weight 32 suspended on the knife 29 (Figure 9).
This standard weight 32 has a value equal to a fraction of f so that a point on the calibration line of the instrument can be checked.

This calibration is performed before the device operates (Figure 9). When in operation the arm 31 is raised (FIG. 8).

Thus, without any part of the weighing instrument being dismantled, it will be possible to automatically calibrate this instrument.

Claims (5)

1 / Weighing instrument with associated dynamometer, characterized in that it comprises a box containing, on the one hand said dynamometer which is vertically drawn and, on the other hand, a system of reduction levers comprising a series of lever arms as well as a system of support columns each lever arm comprising a knife placed on a support column, a knife connected to a knife of the next arm by a communicator, if it is not the last arm in the series, and a knife connected to the preceding arm by a communicator, if it is not the first arm of the series, the first arm of the series comprising a knife which can be connected to a pull rod coming from the load support which slides through an opening in the box, the last arm can be connected to the dynamometer rod, the support columns and the dynamometer being secured to the base intended to be connected to the load support. 2 / weighing instrument according to claim 1, characterized in that the knives connected by communicators can be positioned at several points of the arms. 3 / weighing instrument according to one of the preceding claims, characterized in that from the second arm of the series the arms comprise an additional knife aligned with the pull rod, the end of the pull rod being connectable to one of these additional knives. 4 / weighing instrument according to one of the preceding claims, characterized in that it comprises means making it possible to apply a standard weight to the last arm allowing the calibration of the instrument. 5 / weighing instrument according to one of the preceding claims, characterized in that the position of the base is adjustable relative to the load support.