GB2597932A - A method of producing custom arch supports - Google Patents

Abstract

The position of the ends of the arch, its height and depth at the highest point are established by measurements taken from the unloaded longitudinal arch of a foot relative to one datum line running from the heel to the big toe and another perpendicular datum line behind the heel. The measurements are applied to a computer aided design program to model the space between the arch and shoe. The CAD sketches are lofted to produce a solid, slices and sent to a 3d printer. The height and highest point may be established by drawing a line onto a cone shaped tool, the angle of the cone preferably being 45 degrees to the horizontal. An angled probe may be used to plot points from which the measurements may be derived. The measurements may be obtained by means of scanning, photography or mechanical means. The arch supports may be milled or cut from a block and are preferably flexible.

Description

A method of producing custom arch supports This invention relates to the design and production of custom arch supports.

For some people conventional full length or three quarter length orthotics are unsatisfactory because they take up too much room in their shoes, are too hard or rigid or do not provide adequate support at the arch.

A less intrusive solution are supports for the arch alone. However off the shelf versions of these are very hit or miss. Custom versions are not readily available and are expensive as they are usually hand crafted from casts of the feet. Casting arch supports in situ is sometimes used for skates and ski boots but not readily available for other footwear.

The objective of the invention is to provide a method of producing accurate and comfortable arch supports based on measurements of the unloaded arch and designed to fill the void in the shoe or other footwear into which the arch would otherwise collapse.

The invention consists of a method of producing custom arch supports by measuring the unloaded longitudinal arch, applying these measurements to a computer aided design model of the void between the arch and the shoe or other footwear to produce a solid which is realised by 3d printing or some other suitable method.

The invention will now be described in detail with reference to the following drawings in which: Figure 1 shows the positioning of a foot relative to the datum lines for measuring and illustrates the marks made by the measuring tools.

Figure 2 shows a cross section through the arch and the use of a conical tool to establish the position and height of the arch.

Figure 3 shows a cross section through the arch and the use of a thin probe to measure the depth of the arch.

Figure 4 shows a simplified example of the sketches used in the arch support design using a computer aided design program.

Figures 5 shows a simplified example of the sketch used for the highest point of the arch in the computer aided design program.

Figure 6 shows a simplified example of the sketch used for the ends of the arch.

Figure 7 shows the solid produced by lofting the sketches in the computer aided design program.

The foot is placed on a sheet of paper with the side of the heel and the base of the big toe joint placed against datum line 2 and the heel against datum line 1, as illustrated in figure 1.

To measure the unloaded arch the person sits with the knee vertically above the ankle and the weight of the leg principally on the heel with the pad of the foot resting on the paper.

A cone shaped tool (figure 2, 3) with an angle (figure 2, 18) of say 45 degrees to the horizontal and a radius of say 50mm at the base (figure 2, 15) with a hole down the centre to accommodate a pencil, is placed against the side of the foot and using the pencil the cone is held in contact with the foot and the paper whilst being drawn along the entire side of the foot, to produce a line on the paper.

A probe (figure 3, 4) is placed, perpendicular to datum line 2 at the point where the line produced by the cone tool is closest to datum line 2 (figure 1, 8) and slid as far as it will go under the arch with gentle pressure, and a mark made on the paper at the end of the probe.

This procedure is carried out for each foot.

The resulting charts (figure 1) are analysed to obtain:-a) The position of the elements of the arch relative to datum line 1, the heel end 7, the highest point of the arch 8 and the toe end 9 are all determined relative to datum line 1, Measurements from datum line 1 are shown as 23, 24 and 25 respectively.

b) The height of the arch above datum line 2 at its highest point. See figure 2, In this example the angle of the side of the cone tool figure 2, 18 is 45 degrees to the horizontal so the height of the arch at datum line 2 is equal to the distance between the edge of the cone at it's base from datum line 2, figure 2, 19 which can be determined by subtracting the distance between the closest point of the curve and datum line 2, figure 2, 16 from the radius of the base of the cone tool figure2, 15.

c) The depth of the arch relative to datum line 2 at its highest point. See figure 3. The depth of the arch from datum line 2 is shown as 21 and obtained by subtracting the distance between the mark made at the end of the probe (figure 1, 6) and datum line 2 shown as 22 from the length of the probe 20.

In other embodiments of this invention these measurements may be obtained by scanning, photography or other mechanical devices.

Three sketches are created in a computer aided design program to model the space between the arch and shoe, see figure 4. These are placed along datum line 2 at the distances from datum line 1 determined from figure 1 (23, 24 and 25).

The central sketch (see figure 5) has a line starting tangential to the horizontal at point 12 which is set the depth of the arch (21) from datum line 2, and rising to the maximum height of the arch 19 at datum line 2, the line down from this point starts tangential to the vertical and runs to a point set back to allow for the curve of the shoe insole at the instep 14 and at a height allowing for a rise in the shoe insole 13. The bottom line starting from point 12 starts tangential to the horizontal to meet the downward line at the intersection of 13 and 14 The sketches at the heel and toe ends are simplified versions of the central sketch (see figure 6).

In another embodiment of the invention a different number of sketches may be used.

The sketches are lofted to form a solid (figure 7), which is saved as a digital file, processed through a slicing program and 3d printed in a flexible material such as TPU to produce the arch supports.

In another embodiment of this invention the arch supports are milled or otherwise cut from a block of suitable material.

The arch supports are then fixed to thin insoles made of leather or other suitable material to allow interchangeability between shoes with a similar rise at the instep or fixed directly into shoes, in either case being positioned with reference to the datum lines. They may be glued or otherwise fastened in position.

Claims (8)

1. Claims 1 A method of making custom arch supports consisting of taking measurements of the unloaded longitudinal arch of each foot relative to a datum line running from the inside of the heel to the base of the big toe and relative to another datum line perpendicular to it running behind the heel determining the position of the ends and highest point of the arch and it's height and depth at the highest point, applying these measurements to sketches designed to model the space between the arch and the shoe using a computer aided design program, lofting the sketches to produce a solid for each foot, slicing and 3d printing the solids to produce arch supports, positioning and fixing them onto insoles or directly into shoes, with reference to the datum lines and measurements determined above.
2. 2 The method of claim 1 wherein establishing the position of the ends, highest point of the arch and height of the arch is facilitated by drawing a line using a cone shaped tool.
3. 3 The method of claim 2 wherein the preferred angle of the cone is 45 degrees to the horizontal.
4. 4 The method of claim 2 wherein an angled probe is used to plot points from which the measurements may be derived.
5. The method of claim 1 wherein the measurements are obtained by scanning or photography.
6. 6 The method of claim 1 wherein the measurements are obtained by a mechanical device.
7. 7 The method of claim 1 wherein the arch supports are realised by milling or cutting from a block.
8. 8 The method of claim 1 wherein the arch supports are made of a flexible material.