GB2176302A

GB2176302A - A weighing apparatus

Info

Publication number: GB2176302A
Application number: GB08613668A
Authority: GB
Inventors: Malcolm Peter Carl Tandy
Original assignee: MANGOOD Ltd
Current assignee: MANGOOD Ltd
Priority date: 1985-06-06
Filing date: 1986-06-05
Publication date: 1986-12-17
Also published as: GB8613668D0; GB8514282D0

Abstract

A weighing apparatus has a base plate 1 supporting a circular wall 2 and disposed about the longitudinal axis 5 of the wall 2 is a pillar 6 having a top shelf 8 upon which is located load cell 10. A pair of annular diaphragms 11, 12 are axially spaced along the wall 2 by a tubular member 13. The load cell 10 extends through an aperture 14 in the upper diaphragm 11 to abut the underside of a load plate 23 and disposed on top of the plate is a load platform 26. The construction is such that a load applied at any point on the load platform 26 results in a vertical load being applied to the load cell 10, the tubular member 13 and the diaphragms 11, 12 ensuring that the load applied to the load cell is always a vertical component only. <IMAGE>

Description

SPECIFICATION A weighing apparatus This invention relates to a weighing apparatus.

It is known for a weighing apparatus to comprise one or more load cells in dependence upon the size of the load being weighed. Such a weighing apparatus normally includes a ground engaging base plate spaced from a load platform by the intermediary of a compression load cell. However difficulty arises with the known apparatus when a load is positioned other than directly over the load cell since the platform tends to twist in relation to the load cell with the result that the load is not fully applied to the load cell but only a component thereof.

The present invention seeks to provide a weighing apparatus in which the forementioned difficulty is substantially mitigated.

According to this invention there is provided a weighing apparatus including support means arranged to support a first and a second diaphragm means, said diaphragm means being spaced from one another by a load transferring means and a load plate means arranged to bear upon a load cell and the first diaphragm means whereby a load exerted at any point on the load means results in a vertical load being applied to said load cell by weight transference through the load transferring means and both diaphragm means.

Preferably the support means comprises a base plate and at least one wall extending therefrom.

Conveniently the second diaphragm means is recessed into said at least one wall and the first diaphragm means is located on the top of said at least one wall remote from the base plate.

In a currently preferred embodiment advantageously the at least one wall, the first and second -diaphragm means, the load transferring means and the load plate means each have a circular cross-section disposed about a common axis and the load plate means is a tubular member having opposing ends thereof fixedly secured to a respective diaphragm means. In such an embodiment preferably the first and second diaphragm means are annular and the load cell is mounted on a pillar extending through the second diaphragm means to locate on the base plate and the load cell extends through the first diaphragm means to abut an underside of the load plate means.

Advantageously the load plate means comprises a load plate fixedly secured through the first diaphragm means to the tubular member, a load platform extending over the external periphery of the said at least one wall with a skirt depending from the load platform and over at least a portion of the external periphery of said at least one wall, and a shock absorbing member disposed between the load plate and the load platform.

The first and second diaphragm means may each comprise a plurality of adjacent elastically resilient straps.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a vertical cross-section through the centre line of a weighing apparatus in accordance with this invention, and Figure 2 shows a cross-section taken along double arrow-headed lines A-A of Fig. 1.

In the figures, like reference numerals denote like parts.

The weighing apparatus shown in Figs. 1 and 2 has a square cross-sectioned base plate 1 for contact with the ground having four fixing holes 30 and mounted on the base plate is a circularly cross-sectioned wall 2 which is secured to the base plate 1 by a plurality of bolts 3 threadably engaging tapped holes in the lower edge of the wall 2, the heads of the bolts being located within recesses 4 in the base plate. The circularly cross-sectioned wall 2 has a longitudinal axis 5 and disposed about this longitudinal axis 5 is a pillar 6 secured by fillet welds 7 to the base plate, and at the end of the pillar remote from the base plate is a circularly cross-sectioned shelf 8 secured by fillet welds. 9. Located upon the shelf 8 is a load cell 10.

A pair of annular diaphragms 11, 12 each unitarily made from mild steel are axially spaced along the wall 2 by a tubular member 13, the diaphragms 11, 12 and the tubular member 13 sharing the common axis 5. The operationally upper diaphragm 11 has an aperture 14 which is of smaller diameter than an aperture 15 in the operatively lower diaphragm 12, the difference in diameters being only to aid manufacture, and the diameter of the tubu- lar member 13 is such that the upper end of the member 13 is fully contacted by the diaphragm 11 whereas the lower end of the member 13 is only partially supported by the diaphragm 12. The tubular member 13 is welded by fillet weld 16 to the diaphragm 12 and by fillet welds 17, 18 to the diaphragm 11.The lower diaphragm 12 is fixedly secured with a recess in the wall 2 whereas the upper diaphragm 11 is fixedly secured by a fillet weld 19 on the top of the wall 2. An electrical connection 20 of the load cell extends through an aperture 21 in the tubular member 13 and an aperture 22 in the wall 2 for connection to a utilisation means.

The load cell 10 extends through the aperture 14 to abut the underside of a load plate 23 having a circular cross-section and sharing the common axis 5. The load plate 23 is secured by ten equi-circumferentially spaced bolts 24 through the diaphragm 11 into the top end of the tubular member 13, the heads of the bolts 24 being located in recesses 25 in the top of the load plate. Disposed on top of the load plate 10 is a circular load platform 26 having a diameter such that it extends over the periphery of the wall 2 and depending from the outer rim of the load platform 26 is a skirt which extends partially over the wall 2 to provide protection against rain and dirt entering the load cell 10.Disposed between the load platform 26 and the load plate 23 is a layer of shock absorbing material 28 having the same circular cross-section as the load plate 23, the layer 28 and the load platform 26 both sharing the common axis 5.

In operation a load applied at any point on the load platform 26 results in a vertical load being applied to the load cell 10 by virtue of plate 23, the tubular member 13 and the diaphragms 11 and 12 ensuring that the load applied to the load cell is always a vertical component only.

The weighing apparatus may be used as a single unit in which event the utilisation means to which the load cell lead 20 is attached may be a display such as a digital meter or the weighing apparatus may be arranged with a plurality of other such apparatus to support an object to be weighed. In this latter embodi-ment the leads 20 of each of the load cells would be connected to a multiple weighing instrument which might be a digital instrument so that a user could obtain the overall weight of a load or assess the distribution of weight of the load.

Alternatively instead of each of the diaphragms 11 and 12 being unitary they may each comprise a plurality of adjacent elastically resilient straps (not shown).

Claims

1. A weighing apparatus including support means arranged to support a first and a second diaphragm means, said diaphragm means being spaced from one another by a load transferring means and a load plate means arranged to bear upon a load cell and the first diaphragm means whereby a load exerted at any point on the load means results in a vertical load being applied to said load cell by weight transference through the load transferring means and both diaphragm means.

2. A weighing apparatus as claimed in claim 1 wherein the support means comprises a base plate and at least one wall extending therefrom.

3. A weighing apparatus as claimed in claim 1 or 2 wherein the second diaphragm means is recessed into said at least one wall and the first diaphragm means is located on the top of said at least one wall remote from the base plate.

4. A weighing apparatus as claimed in any preceding claim wherein the at least one wall, the first and second diaphragm means, the load transferring means and the load plate means each have a circular cross-section disposed about a common axis and the load plate means is a tubular member having opposing ends thereof fixedly secured to a respective diaphragm means.

5. A weighing apparatus as claimed in claim 4 wherein the first and second diaphragm means are annular and the load cell is mounted on a pillar extending through the second diaphragm means to locate on the base plate and the load cell extends through the first diaphragm means to abut an underside of the load plate means.

6. A weighing apparatus as claimed in any preceding claim wherein the load plate means comprises a load plate fixedly secured through the first diaphragm means to the tubular member, a load platform extending over the external periphery of the said at least one wall with a skirt depending from the load platform and over at least a portion of the external periphery of said at least one wall, and a shock absorbing member disposed between the load plate and the load platform.

7. A weighing apparatus as claimed in any preceding claim wherein the first and second diaphragm means may each comprise a plurality of adjacent elastically resilient straps.

8. A weighing apparatus substantially as herein described with reference to, and as shown in, the accompanying drawings.