GB2198088A

GB2198088A - Drawing instruments

Info

Publication number: GB2198088A
Application number: GB08624681A
Authority: GB
Inventors: Graham Richard Jones
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-10-15
Filing date: 1986-10-15
Publication date: 1988-06-08
Also published as: GB8624681D0

Abstract

A drawing edge accessory for use with a drawing board is adapted for securement to the drawing board and comprises an extensible drawing edge pivotal angularly over the surface of the drawing board. The accessory comprises a casing adapted for securement to an edge of the drawing board and housing the extensible drawing edge. The casing is pivotal about an axis parallel with the vertical edge of the drawing board when the latter is horizontally disposed. <IMAGE>

Description

A DRAWING ACCESSORY This invention relates to a drawing edge accessory for use in drawing boards, tables, desks or other flat surfaces (hereinafter for convenience simply called " drawing b^ard).

It is an object of the present invention to provide a drawing edge accessory which is simple and versatile in use and which provides a wide range of longitudinal and/or angular drawing positions.

According to the present invention there is provided a drawing edge accessory adapted for securement to a drawing board and comprising a extensible drawing edge pivotal angularly over the surface of the drawing board.

Preferably, the accessory comprises a casing adapted for securement to an edge of the drawing board and housing the extensible drawing edge, the casing being pivotal about an axis parallel with the vertical edge of the drawing board when the latter is horizontally disposed.

Preferably, the accessory comprises a holding device to which the casing is pivotally connected to provide the aforesaid angular movements of the extensible drawing edge.

The holding device may be a resilient clamp or a screw clamp or other convenient releasable fastening device.

The extensible drawing edge is preferably a flexible steel or other metal tape normally anchored at one end and wound within the casing, the other end being external of the casing.

Preferably the metal tape is anchored to a central formation within the casing by a return spring to ensure rewinding of the tape within the casing when not in use.

Preferably the other end of the metal tape is fitted with a puller element.

The tape may have a hole adjacent the puller or at any other convenient location along its length to permit a drawing pin to be inserted thereon to hold the metal tape in longitudinally and/or angularly adjusted position.

The metal tape may bear a measuring scale along its length.

The accessory may incorporate a protractor to ensure correct angular adjustment of the metal tape.

Instead of securing the metal tape by means of a drawing pin, the metal tape may be locked in extended position by a releasable clamp as is well known in conventional extensible measuring tapes.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is an exploded perspective view of the drawing edge accessory according to the present invention; Fig. 2 is a perspective view of a modification; and Fig. 3 is a part-sectional side elevation of the drawing edge accessory.

The drawing edge accessory comprisies two half casings 10, 11 of moulded plastics material having a central anchoring formation 12.

The half casings 10, 11 have a configuration which, when they are locked or sealed together to provide a housing, define an outlet slot 13 and a bearing formation 14 for a pivot pin as described hereafter. The housing 10, 11 is formed with top and bottom open channel formations 15, 16.

The housing 10, 11 is pivotally connected to a clamp device 17 comprising a pivot pin 18 which is held within the bearing arrangment 14, i.e. the half casings 10, 11 are secured together about the pivot pin 18.

The clamp device 17 is cf moulded plastics material and comprises an upper clamp member 19 and a lower clamp member 20. Due to the inherent resiliency of the clamp device 17, the clamp members 19, 20 can easily be resiliently sprung apart to permit the clamp device 17 to be engaged on the edge of a drawing board (not shown). It will be manifest that the housing 10, 11 is pivotal relative to the clamp device 17 about the pivot pin 18.

The drawing edge accessory also comprises a reeled or wound steel tape 21 which is contained within the housing 10, 11. This steel tape 21 is secured to the anchoring formation 12 by a return spring 22 and the tape at its ends which protrudes through the outlet slot 13 has secured thereto a moulded plastics puller element 23. The steel tape 21 can thus be pulled out of the housing 10, 11 for whatever length is desired to extend over the drawing board.

Due to the fact that the housing 10, 11 can be pivoted relative to the clamp device 17 the extended steel tape which provides the drawing edge can be pivoted into a required angular position.

When the puller element 23 is released the return spring 23 rewinds the steel tape 21 back into the housing 10, 11.

In a modification of the clamp device (Fig. 2) the resilient clamp member 20 is replaced by a clamping screw 24.

Claims

CLAIMS:

1. A drawing edge accessory adapted for securement to a drawing board and comprising an extensible drawing edge pivotal angularly over the surface of the drawing board.

2. An accessory as claimed in claim 1, comprising a casing adapted for securement to an edge of the drawing board and housing the extensible drawing edge, the casing being pivotal about an axis parallel with the vertical edge of the drawing board when the latter is horizontally disposed.

3. An accessory as claimed in claim 2, comprising a holding device to which the casing is pivotally connected to provide the aforesaid angular movement of tho cxtens ble drawing edge.

4. An accessory as claimed in claim 3, in which the holding device is a resilient clamp or a screw clamp or other convenient releasable fastening device.

5. An accessory as claimed in any one of claims 2 to 4, in which the extensible drawing edge is a flexible steel or other metal tape normally anchored at one end and wound within the casing, the other end being external of the casing.

6. An accessory as claimed in claim 5, in which the metal tape is anchored to a central formation within the casing by a return spring to ensure rewinding of the tape within the casing when not in use.

7. An accessory as claimed in claim 6, in which the other end of the metal tape is fitted with a puller element.

8. An accessory as claimed in any one of claims 5 to 7 in which the tape has a hole adjacent the puller or at any other convenient location along its length to permit a drawing pin to be inserted therein to hold the metal tape in longitudinally and/or angularly adjusted position.

9. An accessory as claimed in any one of claims 5 to 8, in which the metal tape bears a measuring scale along its length.

10. An accessory as claimed in any one of claims 5 to 9 incorporating a protractor to ensure correct angular adjustment of the metal tape.

11. An accessory as claimed in any one of claims 8 to 10 wherein, instead of securing the metal tape by means of a drawing pin, the metal tape is lockable in extended position by a releasable clamp.

12. A drawing edge accessory, substantially as hereinbefore described with referencc to the accompanying drawing.