GB2117711A

GB2117711A - Device for facilitating proportionment of areas

Info

Publication number: GB2117711A
Application number: GB08210092A
Authority: GB
Inventors: Jeremy Horwood
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-04-05
Filing date: 1982-04-05
Publication date: 1983-10-19

Abstract

A device for facilitating proportionment of areas including a connecting arm (3), two components (1) each having a substantially L- shaped inner edge and means for slidably mounting the component on the connecting arm so that the L-shaped edges face one another to define a substantially rectangular area within them. In use, one of the components is set to a reference position and the other can then be slid along the connecting arm, which is parallel to a diagonal of the rectangular area, thereby to define a fresh area that is proportional in size to the first mentioned area. One of the components may be replaced by a baseboard having two adjacent edges defining between them the L-shape. <IMAGE>

Description

SPECIFICATION Device for facilitating proportionment of areas This invention relates to a device for facilitating proportionment of areas.

According to the present invention, there is provided a device for facilitating proportionment of areas, when draughting for example, the device including a connecting arm, a component having a substantially L-shaped inner edge, means for defining another substantially L-shaped edge, and means for slidably mounting said component on said connecting arm so that said substantially Lshaped edges face one another thereby to define a substantially rectangular area within said edges, the arrangement being such that, in use, said means defining the other Lshaped edge is set to a reference position and said component can then be slid along said connecting arm, which is parallel to a diagonal of said substantially rectangular area, thereby to define a fresh area that is proportional in size to the first mentioned area.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a diagrammatic plan view of a first form of device for facilitating proportionment of areas, Figure 2 is a diagrammatic plan view of a second form of device, Figure 3 is an end view of one of two carriages shown in the device of Fig. 1, and Figures 4, 5 and 6 are views of components provided to lock the carriages in position, Fig. 6 being a side view of the component shown in Fig. 5.

The devices to be described are intended to enable rectangular areas to be increased or decreased in size whilst maintaining their length-to-breadth ratios. Such devices are intended for use in drawing offices, design studios, reprographic houses, photographic studios and other places where, for example, a specific rectangular area of a design calls for a proportional enlargement or reduction of that area to be selected from a graphic illustration or photograph so that a "master" rectangular area can be enlarged and reduced easily.

Referring firstly to Fig. 1 and to Figs. 3 to 6, the device shown therein includes two components 1 which each define a substantially L-shaped inner edge. Each component 1 is slidably mounted by means of a carriage 2 on a connecting arm 3.

It will be seen that, when the two components 1 are mounted on the connecting arm 3, the two components face one another thereby to define a substantially rectangular area within the components, the connecting arm 3 being parallel to one of the diagonals of the substantially rectangular area.

Each carriage 2 is initially able to pivot on its component 1 but is able to be locked in position by means of a locking device 4 illustrated in Figs. 4 to 6. As can be seen from Fig. 3, the carriage 2 has an aperture 5 through which the connecting arm 3 passes and an aperture 6 through which a spindle 7 passes, the spindle 7 extending into the component 1 and being fixed therein. The carriage 2 can normally pivot freely about the spindle 7. The locking device includes a locking member 4A which fits about a pin 4B mounted in the upper end of the spindle 7. It will be seen that, by pivoting the member 4A, a camming surface thereof is caused to press on the upper surface of the carriage 2, thereby tending to compress it and tending to draw the spindle 7 up through it and so tightening the carriage 2 against its component 1.

Each component 1 may be transparent and the carriages 2 are provided with a shallow underside so as not to interfere with the working of the device. The carriage may be formed by extrusion.

To operate the device, which is hand-held, the carriages 2 are unlocked so that the components 1 may pivot freely relatively thereto, and the components 1 are placed over and adjusted so that their inner edges closely surround the borders of an area which is to be filled by a graphic or the like. The locking devices 4 are then locked to clamp the carriages 2 relatively to the components 1, which then define a master area having a fixed length-to-breadth ratio. In this condition of the device, any areas proportioned to the master area will have the same length-tobreadth ratio and the components can be moved relatively to one another only in a single direction parallel to the diagonal of the master area.The device can therefore be positioned freely over a candidate graphic or the like and the device will indicate what areas of that candidate graphic may be exactly enlarged or reduced to fill the master area.

The device shown in Fig. 2 differs from Fig.

1 in that only a single component 1 is provided, the other component being replaced by a transparent base board 8 having two adjacent edges 9 defining between them an Lshape. The base board may have a regular square grid marked on one of its faces. The connecting arm 3 in this case is able to pivot at one end near a corner of the base board 8 and at its other end near the corner of the component 1. However, the connecting arm 3 can be adapted so that it is telescopic or so that it acts as a sliding guide for the compo nent 1 to move along.

The device in Fig. 2 may incorporate a locking mechanism to prevent the connecting arm 3 from moving relatively to the base board 8. Alternatively, the connecting arm may be held in a position relatively to the base board by virtue of its inherent friction, which could be adjustable.

Operation of the device shown in Fig. 2 is similar to the operation of the device shown in Fig. 1. A score line 10 or the like can be marked on the base board 8 to provide a more convenient inner edge of the L-shape to face the component 1.

Claims

1. A device for facilitating proportionment of areas, when draughting for example, the device including a connecting arm, a component having a substantially L-shaped inner edge, means for defining another substantially L-shaped edge, and means for slidably mounting said component on said connecting arm so that said substantially L-shaped edges face one another thereby to define a substantially rectangular area within said edges, the arrangement being such that, in use, said means defining the other L-shaped edge is set to a reference position and said component can then be slid along said connecting arm, which is parallel to a diagonal of said substantially rectangular area, thereby to define a fresh area that is proportional in size to the first mentioned area.

2. A device as claimed in claim 1, wherein said means for defining another substantially L-shaped edge is a further said component, said further component also having said means for slidably mounting it on said connecting arm.

3. A device as claimed in claim 1, wherein said means for defining another substantially L-shaped edge is constituted by a transparent baseboard having two adjacent edges defining between them an L-shape.

4. A device as claimed in claim 3, wherein said baseboard has a score line marked thereon to provide said L-shape.

5. A device as claimed in claim 3 or 4, wherein said connecting arm is telescopic.

6. A device as claimed in claim 3 or 4, wherein said connecting arm acts as a sliding guide for said component to move along.

7. A device as claimed in any one of claims 3 to 6, and incorporating a locking mechanism to prevent said connecting arm from moving relatively to the baseboard.

8. A device as claimed in any one of the preceding claims, wherein the or each component is provided with a locking device to lock the component relatively to said connecting arm.

9. A device for facilitating proportionment of areas, substantially as hereinbefore described with reference to Fig. 1 and to Figs. 3 to 6, or to Fig. 2, of the accompanying drawings.