GB2154182A - Technical drawing device - Google Patents

Abstract

A device primarily designed for technical drawing is characterized by an angular sliding mechanism (at 45 DEG or other angle) that allows movement in both horizontal and vertical direction. The sliding member (A) consists of a pair of straight edges mounted perpendicularly to one another having graduated edges a to f with common zero points in the corners, taking into account the average thickness of the pencil, the member A being mounted on an edge g of a second member B to slide thereupon, the member B being designed to cut said edge g at an angle theta to a given line when an edge h of the member B is cut on said given line. This eliminates the conventional marking off of dimensions. Ideally the entire device is rested upon a conventional horizontal parallel slide, moving freely to the left or right as required. There is scope to adapt the device for the purpose of scribing or guiding along a cutting or sawing tool and the like. <IMAGE>

Description

SPECIFICATION Technical drawing device This device is characterized by its sliding mechanism which is angular and serves both horizontal and vertical movements and by its graduated edges that have common zero positions and virtually eliminate the usual marking off of dimensions.

It is essential that the device be used in conjunction with a bottom rest on the drawing board. Ideally this would be the conventional horizontal parallel slide. Failing availability of the latter a single fixed bottom rest may suffice on the smaller boards, whilst for the larger boards a rest adjustable to convenient set heights may be conceived, taking into account that the proposed device has its own range of say 25 cm. Alternatively one may consider the use of an ordinary Tee Square clamped down in required positions. Such improvisations do not - of course - form part of the invention, but merely illustrate the possibility of offering an inexpensive alternative to the costly and elaborate draughting machines.

The standard construction of the device is illustrated by Figure 1, in which case angle () is 45".

Part A consists of three pairs of graduated edges (a to f), each pair having a common zero point in the corner, taking into account an agreed average thickness of the pencil (or other instrument's) point. The zero markings are prolonged, for easy alignment, and show up on the figure in the shape of a near square. Part A has a sliding movement along edge g of part B, which normally rests on its edge h, if so required on edge I, or, for drawing projections at 45", on edge k. Part C, riveted on A, is a connecting piece that slips under E and is held in position by part D. Two spacers F (same thickness as C) are provided, on top of which strip E is assembled by knurled nuts, to allow dismantling (during transport or for storage). Elsewhere rivets may be used.

To operate the instrument part D is held between thumb and index of the left hand, whilst the little finger is allowed to rest against part H for steadying purposes.

For maximum effect it is proposed that clear Perspex material be used for all parts. Recommended thicknesses:A,B:3mm.-C,E,F:4l/2mm.-D,H:6 mm.

The thickness of 6 mm. for D would allow for a small spring to be fitted at G, to take up any slack and ensure a smooth sliding movement.

Figure 1 is drawn to approx. 4 true size and for practical reasons mm. - graduations are therefore not shown. The numbers refer to cm.

A'few graduations are shown along edge g (part A shown at the zero setting) to illustrate an alternative way of obtaining dimensions. Whilst maintaining the same scale in Figure 1, this is no longer the case in Figure 2, where, for special purposes, graduations along the oblique edge would produce a drawing half the size of that obtained when using the rulers' graduations. But note, for this to be consistent, we have to rest the instrument on its other side as in Figure 3 for the vertical dimensions.

If we now define angle 0 to be arc sin. 21, we may yet obtain another scale which is "1/4 ruler scale". We now measure the vertical dimensions as per Figure 2 and the horizontal dimensions as per Figure 3.

The choice of three scales (1,21, t) offers scope for special applications e.g. architecture, pictorial drawing.

A further application of the special purpose model is the copying of a drawing from one scale into another. In this case measuring, in whatever scale, does not take place at all, except for checking purposes. Assume that the shaded rectangle is a component that forms part of a machine assembly and a detailed drawing of that component is to be produced at twice the scale. Lay a sheet of transparent drawing paper over the existing assembly bearing in mind that the copy produced will always show up at right angle to the original figure. Copying will take place in two stages, as per Figures 2 and 3.

A special mention has to be made in respect of existing pantograph draughting machines. These by their very nature being highly mobile, mounting of the entire device would not be warranted, but we could adapt the basic design of part A (see Figure 4) to be fitted instead of existing separate rulers and thus eliminate the need for marking off of dimensions.

Such basic instrument, as outlined in Figure 4, may also find its applications where speed and efficiency are not of prime importance; thus such instrument may be of use to students, especially when used in conjunction with a Tee Square.

1. A device, primarily designed for technical drawing, that is characterized by its oblique (at 45" or other angle) sliding mechanism that allows adjustment of the sliding member in either horizontal or vertical direction. The sliding member incorporates a number of (usually) graduated edges with common zero points in the corners, taking into account the average thickness of the pencil, or other tool, used.

2. A device as per claim 1, having - in addition or solely - graduations along its oblique sliding edge and a marker on the sliding member.

3. A device as per claim 1, without graduations on the sliding member.

4. A body of graduated edges, as described in claim 1, detached from the remainder of the device and adapted for mounting on existing draughting machines or in other situations (Figure 4).

5. A technical drawing device substantially as described and with reference to Figures 1-3 of the accompanying drawing.

6. A device as per claims 1, 2, 3 or 5 with the additional feature that part B (Figure 1) is made into an adjustable set square to enable sliding edge g to be used at any required angular setting.

7. A device for scribing or guiding along a tool

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Technical drawing device This device is characterized by its sliding mechanism which is angular and serves both horizontal and vertical movements and by its graduated edges that have common zero positions and virtually eliminate the usual marking off of dimensions. It is essential that the device be used in conjunction with a bottom rest on the drawing board. Ideally this would be the conventional horizontal parallel slide. Failing availability of the latter a single fixed bottom rest may suffice on the smaller boards, whilst for the larger boards a rest adjustable to convenient set heights may be conceived, taking into account that the proposed device has its own range of say 25 cm. Alternatively one may consider the use of an ordinary Tee Square clamped down in required positions. Such improvisations do not - of course - form part of the invention, but merely illustrate the possibility of offering an inexpensive alternative to the costly and elaborate draughting machines. The standard construction of the device is illustrated by Figure 1, in which case angle () is 45". Part A consists of three pairs of graduated edges (a to f), each pair having a common zero point in the corner, taking into account an agreed average thickness of the pencil (or other instrument's) point. The zero markings are prolonged, for easy alignment, and show up on the figure in the shape of a near square. Part A has a sliding movement along edge g of part B, which normally rests on its edge h, if so required on edge I, or, for drawing projections at 45", on edge k. Part C, riveted on A, is a connecting piece that slips under E and is held in position by part D. Two spacers F (same thickness as C) are provided, on top of which strip E is assembled by knurled nuts, to allow dismantling (during transport or for storage). Elsewhere rivets may be used. To operate the instrument part D is held between thumb and index of the left hand, whilst the little finger is allowed to rest against part H for steadying purposes. For maximum effect it is proposed that clear Perspex material be used for all parts. Recommended thicknesses:A,B:3mm.-C,E,F:4l/2mm.-D,H:6 mm. The thickness of 6 mm. for D would allow for a small spring to be fitted at G, to take up any slack and ensure a smooth sliding movement. Figure 1 is drawn to approx. 4 true size and for practical reasons mm. - graduations are therefore not shown. The numbers refer to cm. A'few graduations are shown along edge g (part A shown at the zero setting) to illustrate an alternative way of obtaining dimensions. Whilst maintaining the same scale in Figure 1, this is no longer the case in Figure 2, where, for special purposes, graduations along the oblique edge would produce a drawing half the size of that obtained when using the rulers' graduations. But note, for this to be consistent, we have to rest the instrument on its other side as in Figure 3 for the vertical dimensions. If we now define angle 0 to be arc sin. 21, we may yet obtain another scale which is "1/4 ruler scale". We now measure the vertical dimensions as per Figure 2 and the horizontal dimensions as per Figure 3. The choice of three scales (1,21, t) offers scope for special applications e.g. architecture, pictorial drawing. A further application of the special purpose model is the copying of a drawing from one scale into another. In this case measuring, in whatever scale, does not take place at all, except for checking purposes. Assume that the shaded rectangle is a component that forms part of a machine assembly and a detailed drawing of that component is to be produced at twice the scale. Lay a sheet of transparent drawing paper over the existing assembly bearing in mind that the copy produced will always show up at right angle to the original figure. Copying will take place in two stages, as per Figures 2 and 3. A special mention has to be made in respect of existing pantograph draughting machines. These by their very nature being highly mobile, mounting of the entire device would not be warranted, but we could adapt the basic design of part A (see Figure 4) to be fitted instead of existing separate rulers and thus eliminate the need for marking off of dimensions. Such basic instrument, as outlined in Figure 4, may also find its applications where speed and efficiency are not of prime importance; thus such instrument may be of use to students, especially when used in conjunction with a Tee Square. CLAIMS

1. A device, primarily designed for technical drawing, that is characterized by its oblique (at 45" or other angle) sliding mechanism that allows adjustment of the sliding member in either horizontal or vertical direction. The sliding member incorporates a number of (usually) graduated edges with common zero points in the corners, taking into account the average thickness of the pencil, or other tool, used.

2. A device as per claim 1, having - in addition or solely - graduations along its oblique sliding edge and a marker on the sliding member.

3. A device as per claim 1, without graduations on the sliding member.

4. A body of graduated edges, as described in claim 1, detached from the remainder of the device and adapted for mounting on existing draughting machines or in other situations (Figure 4).

5. A technical drawing device substantially as described and with reference to Figures 1-3 of the accompanying drawing.

6. A device as per claims 1, 2, 3 or 5 with the additional feature that part B (Figure 1) is made into an adjustable set square to enable sliding edge g to be used at any required angular setting.

7. A device for scribing or guiding along a tool suitably adapted but substantially designed along the principles outlined in claims 1 to 6.