GB2025053A

GB2025053A - A Caliper Measuring Instrument

Info

Publication number: GB2025053A
Application number: GB7828855A
Authority: GB
Original assignee: Stanley Tools Ltd
Current assignee: Stanley Works Ltd
Priority date: 1978-07-05
Filing date: 1978-07-05
Publication date: 1980-01-16
Also published as: JPS5512493A; FR2430593A1

Abstract

A caliper measuring instrument comprises a pair of side-by-side steel blades which can be selectively coiled up in a casing 2 or uncoiled to extend self-supportingly and more or less rigidly out of the casing. Two moving jaws 6, 8, forming part of a rigid unitary member are mounted on the ends of the blades, whilst two fixed jaws 5, 7, extend from opposite sides of the casing. One moving jaw and one fixed jaw are for internal measurements, whilst the other moving jaw and other fixed jaw are for external measurements. The casing incorporates an electronic calculator 11. <IMAGE>

Description

SPECIFICATION A Caliper Measuring Instrument This invention relates to a caliper measuring instrument.

According to the invention there is provided a caliper measuring instrument comprising a casing, at least one springy blade which can be selectively coiled up in the casing or uncoiled to extend substantially rigidly out of the casing in self-supporting manner, at least one pair of jaws for taking internal and/or external measurements, one jaw of the or each pair being mounted on the casing and the other jaw of the or each pair being mounted on the springy blade or blades, and means for indicating measurements taken.

The invention will be described by way of example with reference to the accompanying drawings, wherein: Figure 1 is a plan view, partly sectioned, of a caliper measuring instrument embodying the invention; Figure 2 is a side elevation, also partly sectioned, of the instrument of Figure 1; and Figure 3 is a section on line Ill-Ill of Figure 1.

Referring to the drawings, the illustrated caliper measurement instrument 1 comprises a casing 2, two springy blades 3 and 4 which can be selectively coiled up in the casing 2 or uncoiled to extend substantially rigidly out of the casing 2 in self-supporting manner, a first pair of jaws 5 and 6 for taking internal measurements and a second pair of jaws 7 and 8 for taking external measurements.

The casing 2 is of moulded plastics, whilst each of the blades 3 and 4 is of springy steel. The blades 3 and 4 are prestressed in known manner so as to assume an arcuate cross-section when extended out of the casing, as shown in the drawings. This arcuate configuration, shown clearly in Figure 3, maintains the blades substantially rigid, although a certain amount of flexure is of course possible, as is well known with measuring rules having such types of blade.

However, each of the blades 3 and 4 is somewhat wider and possibly thicker than measuring blades of known measuring rules, so as to reduce the flexure of the blades.

The jaws 5 and 7 are rigidly mounted at opposite sides of the casing 2, at the end of the casing from which the blades 3 and 4 protrude.

The jaws 6 and 8 form part of a unitary member 9 which is mounted on the ends of the blades 3 and 4.

For taking an internal measurement, jaws 5 and 6 have outwardly facing surfaces 5a and 6a respectively, both perpendicular to the blades 3 and 4.

For taking external measurements, jaws 7 and 8 are provided with inwardly facing surfaces 7a and 8a respectively, also both perpendicular to the blades 3 and 4. Surface 5a is aligned with surface 7a, whiist surface 6a is aligned with surface 8a, so that any given internal measurement requires the same extension of blades 3 and 4 as an external measurement of the same value. The blade 4 is graduated as shown with a scale 10 in millimetres for measuring the extension of the blades 3 and 4 and hence indicating the value of the internal or external measurement which is being taken.

In a modification, the other blade 3 may, for example, include a similar scale (not shown) in inches.

The casing 2 houses an electronic calculator 11 provided with a visual display 12 and operating keys such as 13 for example.

Preferably, the instrument incorporates means for detecting electronically the extension length of the blades 3 and 4 and storing this automatically in the calculator. The instrument may incorporate known electronic means for storing a measurement value in the calculator after the jaws have been moved, that is to say, after the extension of the blades 3 and 4 has been changed. Indeed, calculator circuitry is now sufficiently advanced to contemplate the provision of two or more memories in the calculator for separately storing different measurement values if required. The calculator may also include a specialised function key for converting metric measurement values to feet and inches measurement values.

To use the instrument 1, if the user is taking an internal measurement, all that is required is to place the jaws 5 and 6 inside the dimension being measured, and then to extend the blades 3 and 4 as much as possible, until the jaws 5 and 6 respectively engage the extremties of the internal dimension being measured.

For taking an external measurement, the blades 3 and 4 are extended (up to one metre out of the casing 2) by more than the external measurement being taken, and the jaws 7 and 8 are then closed towards each other, with the blades 3 and 4 becoming coiled up in the casing 2, until the jaws 7 and 8 engage the outsides of the article being measured.

In either case, either the dimension is read from the scale 10, or it is detected electronically within the calculator.

As is usual with spring steel coilable measuring rules, the surfaces which are convex in the extended position (that is, the uppermost surfaces in Figure 3) come to be on the insides of the coils when the blades 3 and 4 are coiled in the casing 2.

In a modification, not shown, the blades 3 and 4 are spaced more widely apart than shown to accommodate a standard, suitably graduated, measuring rule blade (not shown) in between the blades 3 and 4, for indicating the value of the extension. In this modification, the standard measuring rule blade may be of spring steel, similar to the blades 3 and 4, or alternatively may be a fully flexible measuring tape under constant spring tension by means within the casing 2, so that the measuring rule blade is held taut by being attached at its end the member 9.

Claims

1. A caliper measuring instrument comprising a casing, at least one springy blade which can be selectively coiled up in the casing or uncoiled to extend substantially rigidly out of the casing in self-supporting manner, at least one pair of jaws for taking internal and/or external measurements, one jaw of the or each pair being mounted on the basing and the other jaw of the or each pair being mounted on the springy blade or blades, and means for indicating measurements taken.

2. An instrument as claimed in claim 1, wherein are two spring blades.

3. An instrument as claimed in claim 1 or 2, wherein are two said pairs of jaws.

4. An instrument as claimed in claim 3, wherein the jaws mounted on the casing extend from opposite sides of the casing at an end (of the casing) from which the or each blade extends.

5. An instrument as claimed in claim 3 or 4, wherein the jaws mounted on the springy blade or blades form part of a unitary member mounted on one end of the blade or blades.

6. An instrument as claimed in any preceding claim, wherein the casing includes an electronic calculator.