GB2154755A

GB2154755A - A platform scale

Info

Publication number: GB2154755A
Application number: GB08404523A
Authority: GB
Inventors: Stan Benzies Hanssen
Original assignee: Tricolor Corp
Current assignee: Tricolor Corp
Priority date: 1984-02-21
Filing date: 1984-02-21
Publication date: 1985-09-11
Also published as: GB2154755B; AU3991185A; WO1985003771A1; GB8404523D0

Abstract

A platform scale (1, 2) has weight sensing levers (4, 5) and (7, 8) which each supports a platform (1) via a support device (12) which has a substantially planar member (13) symmetrical about a centre line and which has oppositely directed limbs (14 and 15) which bear on the underside of the platform (1). A dimple (19) in the platform bears on the planar member (13) so that the device (12) as a whole provides relative rotational movement betweeen the platform and the respective lever (4, 5, 6 or 7).

Description

SPECIFICATION A platform scale TECHNICAL FIELD The invention relates to a platform scale, particularly of the personal weighing scale kind.

BACKGROUND ART Platform scales particularly personal weighing scales such as bathroom scales often include a lever system and an internal calibrating support to provide accuracy in weighing with lightness and strength in construction. In order to provide for the accuracy of weighing, in particular, the lever system, or at least the individual levers thereof are often used in combination with knife-edge hangers. These hangers are expensive to manufacture and complicated to install.

DISCLOSURE OF THE INVENTION It is accordingly an object of the invention to seek to mitigate the disadvantage of the prior art.

According to the invention there is provided a platform scale comprising a base, for receiving a weight, supported over the base, and weight sensing means including a plurality of levers supported on the base and providing support for the platform, wherein there is adjacent an end of each lever adjacent the periphery of the base a support device between the platform and the respective lever providing a knife edge bearing for that lever and relative rotational movement between the platform and the lever.

Using the invention it is possible to provide a unitary support device which extends between the lever and the platform.

Preferably each support device may be captive between the platform and respective lever and is maintained in position by the lever.

Each support device may comprise a substantially planar member having a part for bearing on a bearing part of the platform, the knife edge being opposite the bearing part.

The bearing part of the platform may comprise a depression in the platform which extends below (in use) the plane thereof.

The depression may be elongate and and with a curved profile as considered in transverse cross-section.

The part of the device which may bear on the profile may be an edge of the device.

The support device may have projecting support limbs which engage the underside of the platform, in use.

The limbs may project in opposite directions out of the plane of the device.

The knife edge may have an apex angle of 60'.

A part of a personal weighing platform scale embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exploded perspective view of the scale showing the mechanism thereof according to the invention; Figure 2 is an enlarged schematic and elevational view of part of the inner surface of Fig. 1; and Figure 3 is an enlarged side elevational view of the part shown in Fig. 2.

Referring to the drawings, first of all, a platform scale embodying the invention has a platform 1 and a base 2 which has an upstanding rim 3, the platform 1 having a dependent rim or skirt la which in use surrounds the rim 3 to provide a neat appearance. The base 2 includes weight sensing means including primary and secondary levers the primary levers 4 and 5 being secured to a common plate 6 of a calibrating device to form a V-shaped single lever. The secondary levers 7 and 8 hang from respective primary levers 4 and 5 from hangers 9.A dial or mask (part shown) is mounted on a splined spindle 10 so that when that spindle 10 is rotated on deflection of the levers 4,5 and 7, 8 via a rack 11, the splined spindle 10, rack 11 and V-shaped single lever 4,6,5 forming part of a weight indicating mechanism, either a dial or numerical read-out of weight applied to the platform 1 can be read off through a viewing window of the platform 1. It will be appreciated that as the weight indicating mechanism 4,6,5 and calibrating device are known, and form no part of the invention, they will not be referred to in greater detail.

Each lever 4 and 5,6 and 7 is, in the embodiment shown, stamped from a sheet metal plate and is supported upright adjacent one end on the rim 3 of the base 2 at a knife edge. Adjacent the periphery of the base 2 at a position inwards from the rim 3 each lever 4,5,6 or 7 supports the platform 1 via a support device 1 2 between the platform 1 and the respective lever 4,5,6 and 7.

Each support device 1 2 is made from a blank sheet of metal and comprises a substantially planar member 1 3 which is symmetrical about a centre line and has oppositely directed limbs 14 and 1 5 which in use bear on the underside of the platform 1, as considered in use and as shown in Figs. 2 and 3. The planar member 1 3 has a notch or slot 1 6 terminating in a knife edge 1 7 of 60 apex angle for bearing on the lever 8, and opposite the knife edge 1 7 a flat part of surface 1 8 which is an edge of the device and bears on a bearing part 1 9 of the platform 1.The bearing part 1 9 of the platform 1 comprises an elongate depression which is downwardly directed (in use) and has a substantially circular surface profile or configuration so that it has a rolling point contact with the bearing part 1 8 of the support device 1 2.

There are four depressions 1 9 at each corner area of the platform 1 and they are formed therein during fabrication in a relatively single forming step such as pressing or stamping. To assemble the scale each lever 4,5,7,8 is positioned as required and each one has a bearing support device 1 2 supported on it before the scale platform 1 is placed in position, with the four depressions 1 9 bearing respectively on the four bearing parts 18 of the respective support devices 1 2.

A simple cover or decorative panel on the upper (in use) surface of the platform 1 conceals the depressions 19, which do not in any way detract from the comfort of a user of the scale. The depressions 1 9 and their associated bearing devices 1 2 nevertheless accommodate any uneven loading of the platform by the depressions 1 9 or the planar bearing parts 1 8 "rolling" or rotating with respect to one another, so maintaining the knife edge 1 7 in the desired relationship to its respective lever, so that the calibration of the scale is not thrown out of true. The scale thus provides an accurate weight measurement even when the loading applied is asymmetric, in other words the scale can accommodate small or different inclinations or cants of the platform 1 with respect to the base 2 in use.

Claims

1. A platform scale comprising a base, for receiving a weight, supported over the base, and weight sensing means including a plurality of levers supported on the base and providing support for the platform, wherein there is adjacent an end of each lever adjacent the periphery of the base a support device between the platform and the respective lever providing a knife edge bearing for that lever and relative rotational movement between the platform and the lever.

2. A platform scale according to Claim 1, in which each platform support device is captive between the platform and the respective lever and is maintained in position by the lever,

3. A platform scale according to Claim 1 or Claim 2, in which each support device comprises a substantially planar member having a part for bearing on a bearing part of the platform, the knife edge being opposite the bearing part.

4. A platform scale according to Claim 3, the bearing part of the platform comprising a depression in the platform which extends below (in use) the plane thereof.

5. A platform scale according to Claim 4, the depression being elongate and and with a curved profile as considered in transverse cross-section.

6. A platform scale according to Claim 5, the part of the device bearing on the profile being an edge of the device.

7. A platform scale according to any of Claims 3 to 6, the support device having projecting support limbs which engage the underside of the platform, in use.

8. A platform scale according to Claim 7, the limbs projecting in opposite directions out of the plane of the device.

9. A platform scale according to any preceding claim, the knife edge having an apex angle of 60 .

10. A platform scale, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.