GB2503431A - Torque wrench with illuminated window for adjustment scale - Google Patents

Abstract

A hand tool, in particular a torque wrench (2, Figure 1), has a viewing window 8 displaying a scale 10 showing the position of an adjustment part (6, Figure 1), which may be a rotatable part of the handle (4, Figure 1) and which may allow the user to set the torque. Window 8 is illuminated using light source 16, preferably one or more LEDs, powered by a battery 18, and the window may be shaped to distribute the light from source 16 over scale 10. Window 8 may have a line 15 to act as a cursor. Light 16 is preferably illuminated by pressing a button (22, Figure 1) causing the light to illuminate for a few seconds and prolonging the life of battery 18. The illuminated window 8 is particularly suited for manual tools.

Description

Hand Tools This application relates to improvements in certain hand tools having user adjustable settings, particularly, although not exclusively, torque wrenches.

The Applicant has appreciated that whilst in recent times there has been growth in the provision of torque wrenches which provide an electronic digital (typically liquid crystal) display of the torque setting selected by the user, there remains a strong preference in at least some sections of the market, especially the higher quality professional end, for fully manual wrenches with mechanical analogue scales which give a direct indication of the position of the part used to carry out the manual adjustment and thus the torque setting selected by the user.

The present invention aims to improve upon such torque wrenches and when viewed from a first aspect provides a torque wrench comprising: a manual adjustment part for allowing a user to select a torque setting to determine a nominal torque which the wrench will apply; an analogue scale giving an indication of the position of the manual adjustment part and thus the torque setting selected by the user, a transparent viewing window allowing the user to view said scale; and illuminating means comprising a battery-powered light source for illuminating said scale such as to render the scale readable through the viewing window in the absence of ambient light.

The Applicant has appreciated that particularly when high quality, high precision torque wrenches are used professionally, they often have a safety-critical role to perform. The Applicant has also appreciated that they may need to be used in relatively inaccessible places where ambient light is inadequate for reliably being able to read the scale indicating the torque setting selected. Although good practice dictates that in such circumstances the technician should move to another area with greater ambient light every time it is necessary to change or check the torque setting, it is recognised that in practice this may not always happen, especially if the ambient light is only just inadequate. Nonetheless this could compromise safety in some situations. By providing, in accordance with the invention, battery-powered illuminating means in a wrench which would not otherwise require a power supply (since the display is a mechanical rather than an electronic one), this problem is avoided.

The illuminating means could be energised automatically -e.g. by use of a light-level sensor but preferably a button or switch is provided. In a set of embodiments the illuminating means is arranged to turn off automatically after a predetermined time to prevent excessive draining of the battery. It is envisaged that under normal patterns of use the battery could last for several years.

The light source could comprise any suitable low power light source but in general one or more light emitting diodes (LEDs) are preferred.

The illuminating means could be arranged simply to illuminate the scale directly.

However particularly in the embodiments where LEDs are used, the Applicant has appreciated that the relatively directional nature of the light generated produces a single bright spot which makes the scale less easy to read. In a set of embodiments the illuminating means is arranged such that light therefrom is distributed by the viewing window in order to illuminate the scale; i.e. the viewing window acts as a light guide.

Such an arrangement is considered to be novel and inventive in its own right and may be applicable to other hand tools with similar characteristics to torque wrenches in having an analogue scale which it is important to illuminate reliably.

When viewed from a second aspect the invention provides a hand tool comprising: a manual adjustment part for allowing a user to select an operational setting of the tool; an analogue scale giving an indication of the position of the manual adjustment pad and thus the setting selected by the user, a transparent viewing window allowing the user to view said scale; and illuminating means comprising a battery-powered light source for illuminating said scale such as to render the scale readable through the viewing window in the absence of ambient light, wherein the illuminating means is arranged such that light from the light source is distributed by the viewing window in order to illuminate the scale. Again the viewing window can thus act as a light guide.

In a set of embodiments in accordance with either aspect of the invention the viewing window comprises a central portion and at least one peripheral portion, said peripheral portion being thicker in the direction of viewing than the central portion, the light source being arranged to direct light into said peripheral portion in a diiection substantially normal to said diiection of viewing. The thickei peiipheral portion is able to act as a light guide, particularly from an edge of the window adjacent the light source to the opposite edge of the window.

In an advantageous set of embodiments the peripheial portion comprises a radiussed or angled inwardly facing surface. This helps to direct light to the central portion and thus illuminate the scale. The surface could, for example, comprise a pait-circular shape in section but other cuived shapes could also be used. The surface could be continuously curved or stepped.

The thicker peripheral portion could be provided along just one, two or three edges of the window. Preferably it comprises all edges of the window to foim a frame.

This may allow the peripheral portion both to direct light evenly onto the scale and to guide it to the opposite edge of the window.

The central portion of the window could be open but in a set of embodiments comprises a thinnei planar section. The central portion and peripheral portion may conveniently be integrally moulded from plastics. In some embodiments a cursor line may be provided, e.g. printed, on the central portion to give a datum position.

The viewing window described herein may provide ample protection against damage, dirt ingress etc. but equally an additional transparent protective cover could be piovided.

An embodiment of the invention may now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is an isometlic view of a torque wrench to which the invention may be applied; Fig. 2 is an enlarged isometric view of a sub-assembly of the torque wrench of Fig. 1 showing the illumination of the viewing window; Fig. 3 is a plan view of the sub-assembly of Fig. 2 showing the scale; and Fig. 4 is a view of a section through the viewing window illustrating the focussing of light by the peripheral portion thereof.

Fig. 1 shows a mechanical torque wrench. It has a head 2 and an elongate handle 4. At the end of the handle 4 is provided an adjustment sleeve portion 6 which is rotatable relative to the rest of the handle 4 about the axis of the handle. The adjustment sleeve 6 allows the user to set the torque which he or she wishes to apply. An outer protective cover 7 is provided over an internal viewing window 8 described below with reference to Figs. 2 and 3. These Figs. show the internal viewing window 8 which is provided over a scale 10 (shown only in Fig. 3) marked on a collar 11 which is caused to rotate (with appropriate gearing) by the adjustment sleeve 6.

The scale 10 indicates the rotational position of the collar 11 driven by the sleeve 6 and thus the torque setting through markings giving the corresponding torque value in appropriate units (typically Newton*metres and/or Pounds force*feet).

The viewing window 8 comprises a central, relatively thin, planar portion 12 and a thicker peripheral portion 14 forming a frame around the central portion. The inwardly4acing surfaces 14a of the peripheral portion are radiussed in order to focus light onto the central portion 12 and thus onto the scale 10 beneath it as will be appreciated from the description relating to Fig. 4 below. A cursor line 15 is provided on the underside of the central portion 12 to provide a scale datum.

In accordance with the invention the scale 10 is illuminated by means of a light source comprising a pair of LEDs 16 powered by a battery 18. The LEDs 16 abut one edge of the viewing window frame 14. As may be seen from Fig. 4, the light from the LEDs passes horizontally into one of the short edges of the frame 14 and is refracted at the radiussed surface 14a thus resulting in light 20' being directed to the central portion of the window 12 and the scale 10 underneath.

Some of the light from the LEDs also passes into the long edges of the frame 14 which guide the light to the opposite short edge where it is refracted in a similar way after being internally reflected from the far (flat) face of the frame. This means that an even illumination is applied to the scale 10 despite two essentially point sources of light being used.

The LED5 16 may be switched on by a momentary press of a button 22 below the outer cover 7 (see Fig. 1). When the button 22 is pressed the LEDs 16 are illuminated for a few seconds, even if the button 22 is then released.

Claims (10)

1. Claims: 1. A torque wrench comprising: a manual adjustment pad for allowing a user to select a torque setting to determine a nominal torque which the wrench will apply; an analogue scale giving an indication of the position of the manual adjustment part and thus the torque setting selected by the user, a transparent viewing window allowing the user to view said scale; and illuminating means comprising a battery-powered light source for illuminating said scale such as to render the scale readable through the viewing window in the absence of ambient light.
2. 2. A torque wrench as claimed in claim 1 wherein the illuminating means is arranged such that light therefrom is distributed by the viewing window in order to illuminate the scale.
3. 3. A hand tool comprising: a manual adjustment part for allowing a user to select an operational setting of the tool; an analogue scale giving an indication of the position of the manual adjustment part and thus the setting selected by the user, a transparent viewing window allowing the user to view said scale; and illuminating means comprising a battery-powered light source for illuminating said scale such as to render the scale readable through the viewing window in the absence of ambient light wherein the illuminating means is arranged such that light from the light source is distributed by the viewing window in order to illuminate the scale.
4. 4. A torque wrench or hand tool as claimed in claim 2 or 3 wherein the viewing window comprises a central portion and at least one peripheral portion, said peripheral portion being thicker in a direction of viewing than the central portion, the light source being arranged to direct light into said peripheral portion in a direction substantially normal to said direction of viewing.
5. 5. A torque wrench or hand tool as claimed in claim 4 wherein the peripheral portion comprises a radiussed or angled inwardly facing surface,
6. 6. A torque wrench or hand tool as claimed in claim 4 or 5 wherein the thicker peripheral portion is provided along all edges of the window to form a frame.
7. 7. A torque wrench or hand tool as claimed in claim 4, 5 or 6 wherein the central portion of the window comprises a thinner planar section.
8. 8. A torque wrench or hand tool as claimed in claim 7 wherein a cursor line is provided on the central portion to provide a scale datum.
9. 9. A torque wrench or hand tool as claimed in any preceding claim wherein the illuminating means is arranged to turn off automatically after a predetermined time.
10. 10. A torque wrench or hand tool substantially as hereinbefore described with reference to the accompanying drawings.