GB2540954A

GB2540954A - Curve plotting apparatus and its method of use

Info

Publication number: GB2540954A
Application number: GB1513547.8A
Authority: GB
Inventors: Scarisbrick Craig
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-07-31
Filing date: 2015-07-31
Publication date: 2017-02-08
Anticipated expiration: 2035-07-31
Also published as: GB2540954B; GB201513547D0

Abstract

An apparatus for plotting a curve 10 comprising a pair of arms 12a, 12b capable of movement, and means for positioning the arms, the position of the arms capable of defining at least three points A, B, C of the curve R. The proximal ends of each arm may be connected by connection means 16 which enables movement of the arms around a centre pivot point. The connection means may include an aperture 18 at the centre pivot point and the distal ends of each arm may include an indent 14a, 14b, providing the three points of the curve. The apparatus may further comprise offset arms 20a, 20b rigidly fixed to the pair of arms, each offset arm being positioned generally equidistant from the connection means and a connecting rod 22 positioned between the offset arms for enabling adjustment of the angle formed between the pair of arms. The curve may be a railway track layout. Also provided are an apparatus for setting a curve in a model railway track, comprising the apparatus described above with a track guiding means situated at each of the at least three points on the curve, and a method of plotting a curve.

Description

CURVE PLOTTING APPARATUS AND ITS METHOD OF USE

Technical Field Oe The Invention

This invention relates to a curve plotting apparatus and its method of use. In particular, this invention relates to a curve plotting apparatus that can be used to quickly and accurately predict and form curves and track layouts for miniature and model railways. This invention is also particularly useful to predict and plot curvature of construction routes, paths, hedgerows, fence lines, lawn edges and the like prior to installation.

Background

Interest in miniature and model railways is high, and it remains a very popular pastime. Miniature and model railway enthusiasts spend a great deal of time and money trying to produce realistic track layouts and environments.

Because of the generally confined spaces in which miniature and model railway track is set out, the radius of curves used in miniature and model railway track layouts are very different to those encountered on the rail network. There is therefore a need for aesthetically pleasing designs of miniature and model railway layouts that have a realistic track curvature.

The problems with miniature railways are similar to those faced by the rail network. Miniature railways use locomotives and rolling stock that carry passengers and enthusiasts. There is therefore a significant need to design a track layout which is both realistic and provides ride comfort and safety. Since miniature railways are often situated in woodland and/or in spaces with many natural obstacles within the general confines of the route, actually laying out the track can be problematic often requiring much trial-and-error measurement and many iterations before a suitable route can be constructed.

There is often the need to use, or work from, a centre radius point. For example, if a 70' (21.34 m) radius of curvature is needed for a section of track, a 70' (21.34 m) line or tape measure has to be fixed at a centre radius point and that line is then used to plot the track radius. Often because of trees and other natural and manmade obstacles, it is not possible to easily move the line in an arc to plot the curve. This is also very much a trial-and-error approach that cannot be used to produce transition curves, i.e. those curves that are intermediary between straight track and a constant radius curve. Other drawbacks are that the time and effort involved in laying out track can be considerable, and the finished result is still often not realistic and disappointing.

In order to address some of these problems with model railways, various commercial products are available which are pressed-out fixed radius curves for use with flexible track. A set of these fixed radius gauges has to be purchased, as each has a different track radius. They also do not allow the model railway enthusiast to plot or predict the track layout with any great certainty, because they are used simply as a construction aid.

It is an object of the present invention to provide a curve plotting apparatus and its method of use which overcomes the drawbacks associated with known products of this type. The present invention allows for the prediction or plotting of curves for railway tracks to be carried out easily and accurately. Use of the present invention enables the radius of the curve to be continually varied, whilst working within the general confines of the proposed route, such that realistic and complicated railway track layouts and geometries, such as transition curves or compound route curvature, can be easily determined when plotting a route. It is a further object of the present invention to provide a quick and accurate device for plotting or forming construction routes, paths, hedgerows, fence lines, lawn edges and the like that might have to follow a generally long and/or complicated route prior to installation. It is a further object of the present invention to provide an apparatus for plotting the route without the need to use, or work from, a centre radius point, and which can be used to provide an accurate and clear visual impression of the route to be followed. It is a further object of the present invention to provide an apparatus which aids operating safety of miniature railways, and can also help make model railway layouts appear more realistic.

Summary Of The Invention The present invention is described herein and in the claims.

According to the present invention there is provided an apparatus for plotting a curve, comprising: a pair of arms capable of movement; and means for positioning the arms, the position of the arms capable of defining at least three points of the curve.

An advantage of using the present invention is that it can be used to quickly and accurately plot a curve or railway track layout with a high degree of realism and safety.

Preferably, the arms have an upper surface and a lower surface which is in contact with a surface to be plotted when in use.

Further preferably, the upper surface and the lower surface of the arms are generally planar and parallel to each other.

In use, the arms may be elongate and rigid.

Preferably, the arms are complementary and are of equal length.

Further preferably, the pair of arms further comprises; a first arm having a distal end and a proximal end; and a second arm having a distal end and a proximal end, the proximal end of the first arm and the proximal end of the second arm being connected by connection means.

In use, the connection means may enable pivotal, rotational or revolvable movement of the first and second arms around a centre pivot point.

Preferably, the connection means is selected from the group consisting, but not limited to, any one of the following: rotational coupling, rolling bearing, hinge, pivot and mechanical linkage.

Further preferably, the connection means includes an annular opening or aperture at the centre pivot point.

In use, the distal end of the first arm and the distal end of the second arm may each include or define a cutout, notch or indent.

Preferably, the at least three points of the curve are obtained at or adjacent to: the cutout, notch or indent positioned at the distal end of the first arm; the cutout, notch or indent positioned at the distal end of the second arm; and the centre pivot point.

Further preferably, each of the at least three points of the curve are marked with a marking point.

In use, the marking point may be selected from the group consisting, but not limited to, any one of the following: pen, pencil, peg, post, pin, sticker and flag.

Preferably, the means for positioning the arms further comprises: offset arms rigidly fixed to each of the pair of arms, each offset arm being positioned at a location generally equidistant from the connection means; and a connecting rod positioned between the offset arms for enabling adjustment of the angle formed between the position of the arms.

Further preferably, each offset arm extends perpendicularly from each of the pair of arms in a plane substantially parallel to the surface to be plotted.

In use, one end of the connecting rod may be pivotally connected to one of the offset arms via a pivotal connection, the other end of the connecting rod may he fixedly secured to the other one of the offset arms via fastening means secured through one of a plurality of apertures disposed in the connecting rod.

The fastening means may be a threaded fastener.

Preferably, the plurality of apertures disposed in the connecting rod are identified by a first measurement number or letter scale, and which correspond to a plurality of threaded apertures on the other one of the offset arms that are each identified by a second measurement number or letter scale.

Further preferably, each of the first and second measurement number or letter scale correspond to a radius of curvature.

In use, the threaded fastener may include a knurled portion or is selected from the group consisting, but not limited to, any one of the following: slotted head, Allen® head and hexagonal bolt.

Preferably, the other end of the connecting rod is fixedly secured via a guide pin projecting from the other one of the offset arms and which is received within a slotted aperture disposed in the connecting rod.

Further preferably, the connecting rod further comprises indicia that display a curvature radius scale aligned parallel to the slotted aperture.

In use, the guide pin may be threaded or include a clamping mechanism with a marking that aligns to the curvature radius scale to give a visual indication of the radius of curvature.

Preferably, each offset arm is of equal length and is shorter than the pair of arms.

Further preferably, each offset arm is secured to each of the pair of arms via a weld or other fixing.

In use, each of the arms may have a length of about 60" (152.40 cm) to about 96" (243.84 cm).

Preferably, each of the arms has a length of about 72" (182.88 cm) to about 84" (213.36 cm).

Further preferably, each of the arms has a length of about 78" (198.12 cm).

In use, the pair of arms may be formed from mild steel square box section tubing, having a square section of between 20mm to 50mm.

Preferably, the curve is selected from the group consisting, but not limited to, any one of the following: railway track layout, construction route, path, hedgerow, fence line, garden edging border, lawn edging border and the like.

According to the present invention there is provided an apparatus for setting a curve in model railway flexible track, comprising: a pair of arms capable of movement; means for positioning the arms, the position of the arms defining at least three points on the curve; and track guiding means being situated at each of the at least three points on the curve, the track guiding means being dimensioned to abut between the rails of the model railway flexible track and to accord the shape of the model railway flexible track to the curve.

Further preferably, the track guiding means further comprises a round disc, the diameter of the disc corresponds to standard model railway gauges.

In use, each of the arms may have a length of about 8" (20.32 cm) to about 14" (35.56 cm).

Preferably, the apparatus is formed from pressed steel and/or moulded from a resin and/or a hard plastics material.

Further according to the present invention there is provided a method of plotting a curve, comprising the steps of: a) positioning a curve plotting apparatus on a surface, the curve plotting apparatus defining first, second and third points of the curve; b) marking the location of each of the first, second and third points of the curve with a marking point on the surface; c) advancing and aligning the curve plotting apparatus forward to the second and third marked locations to define a fourth point of the curve; and d) successively repeating steps b) and c) until the curve is completed.

It is believed that a curve plotting apparatus and its method of use in accordance with the present invention at least addresses the problems outlined above.

It will be obvious to those skilled in the art that variations of the present invention are possible and it is intended that the present invention may be used other than as specifically described herein.

Brief Description Of The Dra wings

The present invention will now be described by way of example only, and with reference to the accompanying drawings, in which:

Figure 1 is a plan view from above of the curve plotting apparatus in accordance with the present invention arranged in a straight configuration;

Figure 2 is a plan view from above of the curve plotting apparatus of Figure 1 but configured in a curved plotting arrangement;

Figure 3 illustrates how the curve plotting apparatus of the present invention can be used to forward predict or plot a curve;

Figure 4 is an exploded view from above of a second embodiment of the present invention which allows a variable angle adjustment;

Figure 5 is an exploded view from above of a third embodiment of the present invention which comprises location discs or gauges for setting the curves of flexible track in model railways; and

Figure 6 shows the basis of the mathematical method for calculating the design and geometry of the curve plotting apparatus in accordance with the present invention.

Detailed Description Of The Preferred Embodiments The present invention has adopted the approach of using an apparatus to enable a forward prediction of a curve, arc or line based on its previous position. Use of the present invention enables the prediction or plotting of curves for railway tracks to be carried out easily and accurately. Use of the present invention enables the radius of the curve to be continually varied, whilst working within the general confines of the proposed route, such that realistic and complicated railway track layouts and geometries, such as transition curves or compound route curvature, can be easily determined when plotting a route. Advantageously, the present invention also provides a quick and accurate device for plotting or forming construction routes, paths, hedgerows, fence lines, lawn edges and the like that might have to follow a generally long and/or complicated route prior to installation. Further advantageously, the apparatus does away with the need to use, or work from, a centre radius point, and can be used to provide an accurate and clear visual impression of the route to be followed. Use of the present invention aids operating safety of miniature railways, and can also help make model railway layouts appear more realistic.

Referring now to the drawings, a curve plotting apparatus 10 according to the present invention is illustrated in Figures 1 and 2. Specifically, the curve plotting apparatus 10 consists of two elongate members or arms 12a, 12b which are generally of equal length along their long axes. The proximal end of each arm 12a, 12b is pivotally connected 16. The other distal end of each arm 12a, 12b is free to rotate and includes or defines a cutout or notch 14a, 14b. In use, marking through these notches 14a, 14b defines two points or locations, denoted points A and C, respectively, that are needed to plot a curve, which is depicted as dashed line R in Figures 1 and 2.

The pivot 16 between arms 12a, 12b is formed as a midpoint, denoted point B, about which the arms 12a, 12b move relative to. Pivot 16 is formed as a rotational coupling that includes an annular opening or aperture 18 through which the midpoint B in Figures 1 and 2 can be marked. This is in no way intended to be limiting as any number of different forms of rotational coupling, such as, a rolling bearing, hinge or other mechanical linkage could be envisaged. Figures 1 and 2 are plan views from above of the curve plotting apparatus 10 which is used in a generally flat or planar configuration as will be explained.

Figure 1 shows the curve plotting apparatus 10 arranged to form an inline straight, i.e. the three marked points of location A, B, C that can be obtained in use, are all positioned in a straight line along line R. It is the end points A, C which can be marked through notches 14a, 14b, respectively, and the marking of midpoint B through aperture 18 that define the three points on a straight line or curve of constant radius, and shown as line R in Figures 1 and 2.

Figure 1 also shows that shorter lugs or offset arms 20a, 20b are rigidly fixed to each arm 12a, 12b and positioned at a location generally equidistant along the arms 12a, 12b from the pivot 16. In a preferred embodiment, offset arm 20a extends perpendicularly from arm 12a. Likewise, offset arm 20b extends perpendicularly from arm 12b. An adjustable tie or connecting rod 22 is connected between the offset arms 20a, 20b which enables adjustment of the angle formed between the arms 12a, 12b.

One end of the connecting rod 22 is pivotally connected to offset arm 12b via pivot 24. Pivot 24 is formed as a rotational coupling, hinge or rolling bearing. The other end of the connecting rod 22 includes a series of holes 26 that are identified by a measurement number or letter scale (not shown), and which correspond to a plurality of threaded apertures 28 on the adjacent offset arm 20a. The plurality of threaded apertures 28 are also each identified by a measurement number or letter scale (not shown). The connecting rod 22 is then fixedly secured to the offset arm 20a using a threaded fastener (not shown) secured through the corresponding hole 26 in the connecting rod 22. To aid ease of use, the threaded fastener includes a knurled portion. Equally, the skilled person could use a threaded fastener with a slotted or Allen® head, or a hexagonal bolt. This forms a bend relative between the two arms 12a, 12b about pivot 16. The skilled person will understand that the position of the connecting rod 22 can also be set to form an inline straight (as shown in Figure 1) which can be used as a checking method to ensure that the curve layout or structure has not undergone deformation by unintentional force).

When the curve plotting apparatus 10 is set to form a curve, the measurement number 26 on the connecting rod 22 and corresponding threaded aperture 28 define the curve radius, i.e. the distal end points A, C on the arms 12a, 12b and the midpoint B of the pivot 16 in which a single curved line R of constant radius lies on all three points A, B, C, as shown in Figure 2, and illustrated geometrically in Figure 6.

In a preferred embodiment, the elongate arms 12a, 12b are formed from mild steel square box section tubing having a square section of between 20mm to 50mm. The length of each arm 12a, 12b is dimensioned to generally correspond to the task for which it is employed. If the curve plotting apparatus 10 is to be used for plotting miniature railway track layouts, the length of each arm 12a, 12b would be around 78" (198.12 cm). The curve plotting apparatus 10, when so dimensioned, could be used to plot various track radius of between around 30' (9.14 m) and 150' (45.72 m). Of course, the skilled person will understand that the dimensions of the curve plotting apparatus 10, and the position and incidence of the measurement numbers 26 and corresponding threaded apertures 28, can be varied to provide a larger or smaller curve radius.

The construction of the arms 12a, 12b from box section mild steel leads to a welded manufacture, with offset arms 20a, 20b being welded onto arms 12a, 12b at a position that is generally perpendicular to arms 12a, 12b and positioned equidistant from the pivot 16. Clearly whilst the embodiment shown in Figures 1 and 2 is illustrative of a welded construction this is in no way intended to be limiting as the present invention can be implemented in any number of sizes, dimensions and materials. For example, the curve plotting apparatus 10 shown in Figure 5 is designed specifically for model railway applications and can be formed from pressed steel or moulded from a resin or hard plastics material. The length of the arms 12a, 12b for model railway applications would be much smaller, and somewhere in the region of 8" (20.32 cm) to 14" (35.56 cm).

As shown in Figure 2, for plotting a curve, the arms 12a, 12b are able to rotate around pivot 16 to form an angle to each other. The angle a is defined by the arrangement position and incidence of the measurement numbers 26 and corresponding threaded apertures 28 preset to provide the curve to be plotted. The locations indicated by points A, B, C in Figure 2 can be used to provide sufficiently accurate locations when using pins or posts and the like for defining the marked locations. These three locations are marked through the notches 14a, 14b on the end of each of the arms 12a, 12b, and at a midpoint through aperture 18.

The skilled person will appreciate that the locations indicated by points X, Y, Z in Figure 2 can also be used to provide sufficiently accurate marked locations for plotting a curve, and which is shown as dashed line R' in Figure 2. These three locations can be marked at the outer comer points of each of the arms 12a, 12b, denoted points X and Z, and the mid curve outer edge, denoted point Y, adjacent to the pivot 16. Locating these three points on or adjacent to the arms 12a, 12b can be particularity useful for quickly measuring and verifying the radius of curvature of railway track layouts.

Clearly, whilst Figures 1 and 2 are illustrative of a generally flat or planar apparatus 10 having an upper surface for user access and a lower surface which is in contact with the ground, table or track, this is in no way intended to be limiting as the present invention can be implemented in any number of ornate or aesthetically-pleasing configurations. Whilst more ornate features of the apparatus 10 can be included, the actual operation of the apparatus 10 remains the same.

The operation of the curve plotting apparatus 10 is best illustrated in Figure 3.

The curve plotting apparatus 10 operates by forward predicting to locate the next position to be identified. In essence, the operation of the curve plotting apparatus 10 is a step-by-step process that successively increments along the plotted route. Once the first three points have been marked, the next step is to increment the apparatus 10 forward, thereby using the second and third marked locations to predict the fourth and so on. This process can be seen in Figure 3. However, all of the points need to be marked at their location before proceeding to the next forward step, and in use, such marked points can be by way of pen, pencil, peg, post, pin, sticker, flag and the like.

The example depicted in Figure 3 is based on a railway track. The curve plotting apparatus 10 is first arranged to align on the straight section from location A to B. An initial gentle curve is introduced, termed a transition curve and is formed between points B and C by the apparatus 10. The next curve section is then formed by adjusting the apparatus 10 to form a tighter curve, which is to become the constant curve. This section is developed by incrementing forward to locate marked position D. The process is repeated, to point E, and the radius of curvature can be varied as the route progresses. The method can be used to produce complex curvature arrangements, such as compound curves or even spiral formations. However, to be consistent and accurate, each forward predicted point has to be indicated.

Figure 4 shows a second embodiment of the curve plotting apparatus 10. The construction of the second embodiment is very similar to that of the first embodiment and corresponding features have been given the same reference numerals. The second embodiment differs from the first embodiment in that the preset measurement numbers 26 and corresponding threaded apertures 28 have instead been replaced by a variable angle adjustment. This comprises a slotted aperture 30 in the connecting rod 22. Also displayed on the connecting rod 22 are indicia that display a curvature radius scale 34. A guide pin 32 permits translation movement within the slot 30 aligned parallel to the curvature radius scale 34 indicated on the connecting rod 22. The guide pin 32 could be threaded or include a clamping mechanism (not shown) with a marking that aligns with the radius scale 34 to give a direct reading for curvature. This second embodiment of the invention may be less accurate to use as it depends upon a user reading the radius scale, but the benefits are that the apparatus 10 is infinitely adjustable between curvature limits.

Figure 5 shows a third embodiment of the curve plotting apparatus 10. The construction of the third embodiment is very similar to that of the first embodiment and corresponding features have been given the same reference numerals. The third embodiment differs from the first embodiment in that interchangeable or fixed location gauges are provided for use in setting the track curvature of model railway flexible track. The curve plotting apparatus 10 operates in the same way as described, but with round discs 38 secured via an annular connection means 36 at the three locations A, B, C on the apparatus 10 which are used to form the curve.

The diameter of the discs 38 correspond to standard model railway gauges, and which fit neatly between the rails of flexible track (not shown). By setting the curve plotting apparatus 10 to the desired curve, the flexible track curvature can be set by positioning the three discs 38 within the track gauge. This defines the curve and the fixing position which, in use, would be marked by pencil or an indentation made through the centre hole of each disc 38.

The relative size of the curve plotting apparatus 10 depicted in Figure 5 for model railway applications is very different to the embodiments shown in Figures 1 to 4. The length of the arms 12a, 12b would in the region of 8" (20.32 cm) to 14" (35.56 cm). The diameter of the discs 38 would be configured so that they sit inside the rails of flexible track that is available in marketplace. For example, for N gauge track, the disc 38 would have a diameter of less than 0.353" (8.97 mm). For 00 gauge track, the disc 38 would have a diameter of less than 0.75" (19.05 mm). Likewise, for 0 gauge track, the disc 38 would have a diameter of less than 1.25" (31.75 mm).

Figure 6 illustrates the basis of the mathematical method for calculating the geometry of the apparatus 10. The design of the curve plotting apparatus 10 was implemented using two mathematical equations which resulted in having two unknowns. An iteratively solution method using a computer program was necessary to provide the solution using guesses and modified guesses to reach answers that solved both equations. The basis of the geometry can be shown in Figure 6, which shows the dimensions used for calculations.

Where: R = track curvature radius a = half the chord length o = offset distance (maximum) from curve to chord h = short chord length (two in total, in the practical apparatus 10 the distance between points A and B, and points B and C)

r = major radius part used as one of the guesses for calculating R

At a high-level, the two equations calculated for individual R. The two different guesses used in the equations would produce individual Rs based on the guesses, but the correct single value for R was only achieved when the difference between the individual Rs was zero. This zero error resulted in the track curvature radius being resolved. When this condition is achieved then the offset distance is defined and the three points on the arms 12a, 12b lie on a constant curve, thereby defining the curvature radius. The process for finding the correct single R can take several or many iterations.

The invention is not intended to be limited to the details of the embodiments described herein, which are described by way of example only. Various additions and alternations may be made to the present invention without departing from the scope of the invention. For example, although particular embodiments refer to implementing the present invention on miniature and model railways, this is in no way intended to be limiting as, in use, the present invention can be applied to plot construction routes, paths, hedgerows, fence lines, lawn edges and the like that might have to follow a generally long and/or complicated route prior to installation.

Claims

1. An apparatus for plotting a curve, comprising: a pair of arms capable of movement; and means for positioning the arms, the position of the arms capable of defining at least three points of the curve.

2. The apparatus as claimed in claim 1, wherein the arms have an upper surface and a lower surface which is in contact with a surface to be plotted when in use.

3. The apparatus as claimed in claim 2, wherein the upper surface and the lower surface of the arms are generally planar and parallel to each other.

4. The apparatus as claimed in any of the preceding claims, wherein the arms are elongate and rigid.

5. The apparatus as claimed in any of the preceding claims, wherein the arms are complementary and are of equal length.

6. The apparatus as claimed in any of the preceding claims, wherein the pair of arms further comprises: a first arm having a distal end and a proximal end; and a second arm having a distal end and a proximal end, the proximal end of the first arm and the proximal end of the second arm being connected by connection means.

7. The apparatus as claimed in claim 6, wherein the connection means enabling pivotal, rotational or revolvable movement of the first and second arms around a centre pivot point.

8. The apparatus as claimed in claims 6 or 7, wherein the connection means is selected from the group consisting, but not limited to, any one of the following: rotational coupling, rolling bearing, hinge, pivot and mechanical linkage.

9. The apparatus as claimed in any of claims 6 to 8, wherein the connection means includes an annular opening or aperture at the centre pivot point.

10. The apparatus as claimed in claim 6, wherein the distal end of the first arm and the distal end of the second arm each including or defining a cutout, notch or indent.

11. The apparatus as claimed in claim 10, wherein the at least three points of the curve are obtained at or adjacent to: the cutout, notch or indent positioned at the distal end of the first arm; the cutout, notch or indent positioned at the distal end of the second arm; and the centre pivot point.

12. The apparatus as claimed in claim 1, wherein each of the at least three points of the curve are marked with a marking point.

13. The apparatus as claimed in claim 12, wherein the marking point is selected from the group consisting, but not limited to, any one of the following; pen, pencil, peg, post, pin, sticker and flag.

14. The apparatus as claimed in claim 1, wherein the means for positioning the arms further comprises: offset arms rigidly fixed to each of the pair of arms, each offset arm being positioned at a location generally equidistant from the connection means; and a connecting rod positioned between the offset arms for enabling adjustment of the angle formed between the position of the arms.

15. The apparatus as claimed in claim 14, wherein each offset arm extends perpendicularly from each of the pair of arms in a plane substantially parallel to the surface to be plotted.

16. The apparatus as claimed in claims 14 or 15, wherein one end of the connecting rod is pivotally connected to one of the offset arms via a pivotal connection, the other end of the connecting rod is fixedly secured to the other one of the offset arms via fastening means secured through one of a plurality of apertures disposed in the connecting rod.

17. The apparatus as claimed in claim 16, wherein the fastening means is a threaded fastener.

18. The apparatus as claimed in claim 17, wherein the plurality of apertures disposed in the connecting rod are identified by a first measurement number or letter scale, and which correspond to a plurality of threaded apertures on the other one of the offset arms that are each identified by a second measurement number or letter scale.

19. The apparatus as claimed in claim 18, wherein each of the first and second measurement number or letter scale correspond to a radius of curvature.

20. The apparatus as claimed in claim 17, wherein the threaded fastener includes a knurled portion or is selected from the group consisting, but not limited to, any one of the following: slotted head, Allen® head and hexagonal bolt.

21. The apparatus as claimed in claim 17, wherein the other end of the connecting rod is fixedly secured via a guide pin projecting from the other one of the offset arms and which is received within a slotted aperture disposed in the connecting rod.

22. The apparatus as claimed in claim 21, wherein the connecting rod further comprises indicia that display a curvature radius scale aligned parallel to the slotted aperture.

23. The apparatus as claimed in claim 22, wherein the guide pin is threaded or includes a clamping mechanism with a marking that aligns to the curvature radius scale to give a visual indication of the radius of curvature.

24. The apparatus as claimed in claim 14, wherein each offset arm is of equal length and is shorter than the pair of arms.

25. The apparatus as claimed in claim 14, wherein each offset arm is secured to each of the pair of arms via a weld or other fixing.

26. The apparatus as claimed in any of the preceding claims, wherein each of the arms has a length of about 60" (152.40 cm) to about 96" (243.84 cm).

27. The apparatus as claimed in claim 26, wherein each of the arms has a length of about 72" (182.88 cm) to about 84" (213.36 cm).

28. The apparatus as claimed in claim 27, wherein each of the arms has a length of about 78" (198.12 cm).

29. The apparatus as claimed in any of the preceding claims, wherein the pair of arms is formed from mild steel square box section tubing, having a square section of between 20mm to 50mm.

30. The apparatus as claimed in any of the preceding claims, wherein the curve is selected from the group consisting, but not limited to, any one of the following: railway track layout, construction route, path, hedgerow, fence line, garden edging border, lawn edging border and the like.

31. An apparatus for setting a curve in model railway flexible track, comprising: a pair of arms capable of movement; means for positioning the arms, the position of the arms defining at least three points on the curve; and track guiding means being situated at each of the at least three points on the curve, the track guiding means being dimensioned to abut between the rails of the model railway flexible track and to accord the shape of the model railway flexible track to the curve.

32. The apparatus as claimed in claim 31, wherein the track guiding means further comprises a round disc, the diameter of the disc corresponds to standard model railway gauges.

33. The apparatus as claimed in claims 31 and 32, wherein each of the arms has a length of about 8" (20.32 cm) to about 14" (35.56 cm).

34. The apparatus as claimed in any of claims 31 to 33, wherein the apparatus is formed from pressed steel and/or moulded from a resin and/or a hard plastics material.

35. A method of plotting a curve, comprising the steps of: a) positioning a curve plotting apparatus on a surface, the curve plotting apparatus defining first, second and third points of the curve; b) marking the location of each of the first, second and third points of the curve with a marking point on the surface; c) advancing and aligning the curve plotting apparatus forward to the second and third marked locations to define a fourth point of the curve; and d) successively repeating steps b) and c) until the curve is completed.

36. The curve plotting apparatus or apparatus for setting a curve in model railway flexible track as described herein with reference to Figures 1 to 6 of the accompanying drawings.

37. A method of plotting a curve or track as hereinbefore described.