Angle Measurement Tool

Abstract

A tool for measuring the angle of a component comprises a body 12 having a head end and a tail end, the body being elongate and extending along a tool axis. A head end assembly 10 is carried on the bo

Description

This invention relates to angle measurement tools. It has particular, but not exclusive, application to measurement of the angle of a component during and after installation, such as a fluid conduit in which liquid is intended to flow under the action of gravity. 5 During construction projects, there are various situations in which components must be installed at a specific angle, which is neither horizontal nor vertical. For instance, drain pipes for carrying waste water are installed so as to slope downwards in the direction in which water is intended to flow. This downward slope is typically referred to as the "fall" and can be expressed as a ratio or as an angle. Building regulations will typically specify a range of 10 different values for an acceptable fall in dependence upon the particular circumstances in which a pipe is being installed. Too little fall will cause the water to stagnate and too large a fall will cause flow at excessive speed. If a pipe is installed with an incorrect fall, it may fail an inspection had have to be re-installed, with can result in significant delay and extra cost Similar considerations apply to installation of rainwater gutters and many other situations 15 where water or other liquids are guided to flow under the action of gravity. 20 Tools in the form of spirit levels (otherwise known as bubble levels) that can be configured to measure angles other than horizontal or vertical are well-known. However, these typically have to be set up by rotating a measuring device (typically a vial containing liquid) to a specific angle with respect to main body of the level. This is potentially error-prone and the presence of moving components in the level is undesirable for applications, such as belowground installation, where the level is likely to be contaminated with soil and water. Such known spirit levels can be difficult to read other than from a side-on direction, which is a further disadvantage for use in below-ground applications. An aim of this invention is to provide a tool that can be used by an installer to assess the angle 25 of a component such as the fall of a pipe or other liquid conduit during installation that resolves or at least ameliorates the disadvantages of known tools. To this end, the invention provides a tool for measuring the angle of a component comprising a body having a head end and a tail end, the body being elongate and extending along a tool axis; and 30 a head end assembly carried on the body in the vicinity of the head end, the head end assembly including: a measurement device, the measurement device having a measurement axis and a level indicator, the level indicator being operative to provide an indication to a user that the level axis is horizontal; wherein the measurement axis is coaxial with the tool axis; a support section that has a plurality of peripheral support surfaces, each 5 support surface having a measuring height that is the minimum radial distance between the axis and the support surface; indicia to indicate to a user which support surface is to be placed upon a component to achieve a specific fall amount; wherein the support section is disposed between the level indicator and the 10 body. Such tools can be used to measure a specific set of angles applicable to a particular field of use. They need have no moving parts and require no calibration or adjustment during use. Most typically, the measurement device is a spirit level vial. In such a vial, the level indicator may be a bubble of gas within a mostly liquid-filled tube or transparent glass, plastic or other 15 suitable material. Alternative electronic measurement devices are available. The body may be tubular and is typically formed of metal. The body may be of constant cross-section. Externally, the body may be of rectangular (e.g., square) section. In such embodiments, each external surface of the body is typically substantially parallel to a respective one of the support surfaces. The length of the body is selected in accordance with 20 the applications in which it will be used and is preferably long enough to avoid undue effects of local variations in angle. For example, a tool used for installation of drainage pipes may be in excess of 300mm or, 500mm (e.g., approximately 900mm) in length. The support section is disposed between the level indicator and the body. Advantageously, the indicia are formed or marked on the support section. The indicia may 25 include characters formed on the support surfaces. Each supporting surface may be marked with indicia to indicate the angle measured when another of the supporting surfaces is an active supporting surface in contact with a component being measured. For example, for an embodiment that has four supporting surfaces arranged in a rectangle, the indicia on any one supporting surface indicates the angle that will be measured when the opposite supporting 30 surface is the active supporting surface. The head assembly is preferably removable from the body to enable replacement of the measurement device. 25 10 24 An embodiment of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings, in which: Figure 1 shows an angle measurement tool being an embodiment of the 5 invention; Figure 2 is an exploded view of the tool of Figure 1; Figure 3 is an end view from a head end of the tool of Figure 1; Figure 4 is an end view from a tail end of the tool of Figure 1; Figure 5 shows a head assembly of the tool of Figure 1 in greater detail; and 10 Figures 6a to 6d show the tool of Figure 1 being used to measure the fall of a pipe in four different configurations. With reference to the figures, an angle measurement tool embodying the invention comprises a head assembly 10, a body 12 and a tailpiece 14. The body 12 is formed from a length of square-section tube having four outer surfaces at 15 right angles to one another. In this case, the tube is a metal tube for durability, but a tube of other materials, such as synthetic composite, could be used instead. The tube is centred on a long axis A of the tool. The tailpiece 14 has a locating portion that is a press fit into an end of the body 12 (referred to as the tail end) and a rectangular transverse closing portion that closes the end of the 20 body 12. The closing portion has an external periphery that closely approximates that of the body 12. The tailpiece 14 may be made of plastic or composite material and serves to protect the tail end of the body 12 from wear and impact damage. The head assembly includes a bubble level vial 20. This is of a type used in a conventional spirit level, which is a transparent vial mostly filled with liquid. A bubble of air within the 25 vial 20 appears centred between indicating lines when the measurement axis of the vial 20 is horizontal. The head assembly 10 further includes an enclosure 22 within which the vial 20 is contained. In this embodiment, the enclosure 22 is formed from two plastic mouldings 24, 26, the mouldings 24, 26 being held together by screws 30. Within each moulding 24, 26, a semi-30 cylindrical recess is formed, the recesses together forming a cylindrical cavity within the enclosure, the vial 20 being retained within the cavity. An opening 32 is formed in each moulding 24, 26 through which the vial 20 is visible. The enclosure has a mounting portion 34 that is of square cross-section with chamfered or rounded corners. The mounting portion 34 is formed by complementarily shaped parts of each moulding 24, 26. The mounting portion 34 extends along an axis that is parallel to the measurement axis of the vial 5 20 contained within the enclosure 22. The mounting portion 34 is inserted into one end of the body, within which it is a close fit, and retained there with screws 36. This ensures that the measurement axis of the vial 20 is coaxial with the long axis A of the tool. The enclosure 22 has a support section 40 that is adjacent to the body 12 in the assembled tool. The support section 40 has a rectangular outline with four supporting sides that extend 10 around, but are not centred on, the long axis A. Each supporting side has a support surface 44i to 444 that extends, for a short distance, parallel to the long axis A and, for a greater distance, parallel to a respective one of the outer surfaces of the body 12. The distance of closest approach of each support surface 44i to 444 is denoted Hi to H4, and referred to as the “measuring height”. 15 In this embodiment, the support section 40 is located axially between the vial 20 and the mounting portion 34, such that the vial 20 projects axially from the tool within the head assembly 10. Being in this position makes the vial readily visible during use of the tool. However, it also makes it vulnerable to damage, although the risk of this is minimised by ensuring that the head assembly 10 is strong and provides protection for the vial 20. As 20 described above, the head assembly 10 is secured within the body 12 by screws 36 and its components are interconnected by screws 30, all of which can be removed to allow replacement of the vial 2 0 in the event of it being broken. The principle of operation of the tool can be seen from Figures 6a to 6d. To carry out a measurement operation, the tool is placed on a pipe 42 that is being installed with a fall that 25 is to be within a specified range. The tailpiece 14 is placed on a relatively high part of the pipe 42 and one supporting surface 44i to 444, referred to as the “active supporting surface", of the support section 40 is placed on a relatively lower part of the pipe 42. In each of the examples shown in Figures 6a to 6d, the long axis A is horizontal, which can be verified by a user by inspection of the vial 20 through one of the openings 32, but the pipe 42 is falling 30 towards the right of the figure. If the vial 20 does not give an indication that it is horizontal, the user will know whether the fall of the pipe 42 is greater or less than intended and can make the appropriate corrections. The angle of the fall at which the long axis A is horizontal is dependent upon which of the four support surfaces 44i to 444 is in contact with the pipe. Assuming that support surface 44„ is 25 10 24 in contact with the pipe 42, and there is a distance L between the point at which the tailpiece 14 and the support surface 44„ make contact with the pipe 42, the fall can be expressed simply as a ratio Hn.L or as an angle tan-1 Indicia showing the ratio and / or angle, as the case may be, are marked visibly, as shown at 50, on the support surface 44i 5 to 444 opposite to the active supporting being surface used to measure the given ratio or angle. In this way, the markings are visible from above while the appropriate support surface 44i to 441 is in contact with the pipe 42 facing down and away from the user. In this embodiment, L^900mm. It has been found that this length is suitable for the installation of drainage pipes, since it is long enough that its reading is not unduly influenced 10 by local variations in the fall over short lengths of the pipe, and it is also capable of bridging pipe joints. The four support surfaces 44i to 444 are specified, in this embodiment, to measure falls of 1:100,1:80,1:60 and 1:40, which gives measuring heights ofH;=9mm, Hz=ll.25mm, / / 3=15mm and / ^4=22.5mm. To presentthe correct indication of fall to a user looking on from above, the support surface 44i is marked "1:60”; 442, "1:40”; 44s, "1:100"; 15 and 442, "1:80".

Claims

1. A tool for measuring the angle of a component comprisinga. a body having a head end and a tail end, the body being elongate and extending along a tool axis; andb. a head end assembly carried on the body in the vicinity of the head end, the head end assembly including:i. a measurement device, the measurement device having a measurement axis and a level indicator, the level indicator being operative to provide an indication to a user that the level indicator is horizontal; wherein the measurement axis is coaxial with the tool axis;ii. a support section that has a plurality of peripheral support surfaces, each support surface having a measuring height that is the minimum radial distance between the axis and the support surface; andiii. indicia to indicate to a user which support surface is to be placed upon aC\J component to achieve a specific fall amount;C—wherein the support section is disposed between the level indicator and the body.1—LO 2. A tool according to claim 1 in which the measurement device is a spirit level vial.CM3. A tool according to claim 1 or claim 2 in which the body is tubular and is of constant crosssection.

4. A tool according to any preceding claim in which the body is externally of rectangular section.

5. A tool according to claim 4 in which each external surface of the body is parallel to a respective one of the support surfaces.

6. A tool according to any preceding claim in which the body is formed of metal.

7. A tool according to any preceding claim in which the length of the body is in excess of 300mm.

8. A tool according to any preceding claim in which the length of the body is in excess of 900mm inlength.

9. A tool according to any preceding claim in which the indicia include characters formed or marked on the support surfaces.

10. A tool according to claim 9 in which each supporting surface is marked with indicia to indicate the angle measured when another of the supporting surfaces is an active supporting surface in contact with a component being measured.

11. A tool according to claim 9 as dependent from claim 4 in which the indicia on any one supporting surface indicates the angle that will be measured when the opposite supporting surface is the active supporting surface.

12. A tool according to any preceding claim in which the head assembly is removable from the body to enable replacement of the measurement device.25 10 24

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