Weighing scales – Collapsible – foldable – knockdown
Patent
1996-03-29
1997-12-09
Donovan, Lincoln
Weighing scales
Collapsible, foldable, knockdown
177131, 177148, 177150, 177190, 177246, 177250, 177251, G01G 1900, G01G 1954
Patent
active
056963556
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a letter weighing device.
It is well known to provide a letter weighing device in the form of a lever to one end of which a letter can be secured, the exact weight of the letter being determined by positioning the lever on a fulcrum such that the lever is in equilibrium in a substantially horizontal position. The position of the fulcrum along the length of the lever is then a measure of the weight of the letter.
Generally in known devices there are predetermined fulcrum points each of which corresponds to a predetermined weight of letter to be supported by the lever. The weight of any one letter is then determined as being greater or less than a particular weight corresponding to one fulcrum point. This is considered adequate to determine the weight of letters for the purposes of postage rates as it is common practice for postal charges to be assessed at rates corresponding to particular ranges of weights. Thus fulcrum points are provided for each of the weights corresponding to a weight at which the postal rate increases from a first to a second rate.
One example of such a known letter weighing device is described in U.S. Pat. No. 1,201,063. This illustrates a combined ruler and postal scale in the form of a ruler which is substantially planar and incorporates a member which can be extended out of the plane of the ruler to define a fulcrum. A letter can be clipped to one end of the ruler so as to project vertically above the plane of the ruler when it is positioned on a flat surface, for example the top of a table. The fulcrum is moved longitudinally relative to the ruler until a point of equilibrium is reached. A scale along the track which can be followed by the fulcrum is then read to determine the weight of the letter. This known device does however present various problems. Firstly, the structure is relatively complicated and therefore manufacturing costs are relatively high. Furthermore, the weighing device is unstable as the letter has to be supported above the lever when it is placed upon a flat surface.
Another known letter weighing device is described in U.S. Pat. No. 2,507,073. This device is in the form of a generally planar ruler incorporating various other devices such a protractors. In contrast to the device described in U.S. Pat. No. 1,201,063, this device is used when weighing letters with its plane substantially vertical. Apertures are provided in the ruler in which fulcrum devices, e.g. pencils can be inserted. Letters are clipped beneath the ruler when being weighed and thus the device is not unstable. However, it is necessary to form in the ruler a relatively large number of apertures if a reasonable range of letter weights can be assessed. Furthermore, use of the device requires an additional implement such as a pencil to serve as a fulcrum.
A still further example of known letter weighing device is described in U.S. Pat. No. 2,612,365. This arrangement is similar to that described in U.S. Pat. No. 2,507,073 in that it is generally planar and in use is positioned in a substantially vertical plane. Rather than providing apertures in which fulcrum devices such as pencils can be inserted however the device incorporates integral pivoting members in the form of pins which are freely rotatable in apertures in the device and can be held by the user when the device is gripping a letter. This arrangement avoids the need for the user to provide a fulcrum member such as a pencil but the resultant structure is relatively complex.
It is an object of the present invention to provide an improved letter weighing device.
According to the present invention, there is provided a letter weighing device comprising an elongate member having upper and lower elongate surfaces, the upper elongate surface supporting two spaced apart and substantially parallel resilient ribs extending longitudinally along the elongate member so as to define a recess therebetween, at least a portion of each rib extending in a direction generally towards the other rib, a fulcrum member mounted upo
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patent: 243753 (1881-07-01), Barton
patent: 440959 (1890-11-01), O'Marra
patent: 1201063 (1916-10-01), Litchfield
patent: 1872646 (1932-08-01), Behrens
patent: 2963286 (1960-12-01), Fischer
patent: 4840241 (1989-06-01), Ishikawa
Abstract of DE 2 931 419 in English No Date Given.
Donovan Lincoln
Gibson Randy W.
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