GB2200754A

GB2200754A - Improvements in or relating to a measuring device

Info

Publication number: GB2200754A
Application number: GB08720009A
Authority: GB
Inventors: Mark Reindorp
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-02-06
Filing date: 1987-08-25
Publication date: 1988-08-10
Anticipated expiration: 2007-08-25
Also published as: GB8720009D0; GB2200754B; GB8702695D0

Abstract

A measuring device for measuring a distance comprises a roller 2 having an outer periphery 3 to be rolled along the distance to be measured. Optical means generate a signal indicative of the number of rotations or part rotations of the roller. Electronic means calculate the distance traversed by the roller. A display 8 is provided to indicate the measured distance. The measuring device incorporates a manually operable button 6 adapted to add, automatically, to the displayed value a distance equal to the radius of the roller so that the device can be used to measure accurately in to corners. Further buttons 5, 7 enable to measured distances to be multiplied to give an area, and the display to record the distance measured in either metric or imperial units. An alternative roller of different diameter can be exchanged with the roller 2. <IMAGE>

Description

Improvements in or relating to a measuring device The present invention relates to a measuring device At the present point in time it is common practice for tape measures to be used by builders, decorators, and by other people involved in taking measurements. Where a distance has to be measured which is longer than a tape measure it can be difficult to obtain an accurate result.

Also, if the distance which is not linear has to be measured, such as the length of wall present in a bay window, difficulties may arise. Also, if a long length has to be measured it is sometimes necessary for two people to be present, one to hold one end of the tape measure, and one to carry out the measuring process.

Various proposals have been made to overcome these problems, and it has been proposed previously to provide a portable hand held device having an exposed roller which can be brought into contact with the surface to be measured and which may drawn along that surface, causing the roller to rotate. The device includes means responsive to rotation of the roller to provide a signal which is indicative of the distance traversed by the roller. The device may also include a calculating device to enable calculations to be formed on the measured distance. Examples of such prior art devices are disclosed in British Patent Specification 1586602 and International Patent Publication W085/05175.The prior proposed devices suffer from a disadvantage in that, if a measurement is to be made, for example the measurement of a wall, in which the starting point and/or the finishing point of the measurement is within a right-angled corner, it is not possible to locate the roller in contact with the wall exactly in the corner. Thus, an error can arise.

A further disadvantage of the prior art is that each example of the prior art measuring device is it is only adapted to make measurements in one particular order of magnitude.

The present invention seeks to overcome the abovedescribed disadvantages of the prior art.

According to this invention there is provided a measuring device for measuring a distance, said device comprising a roller means having an outer periphery adapted to be rolled along the distance to be measured, means adapted to generate a signal indicative of the number of rotations or part rotations of said roller means, electronic means to calculate, from said measured value, the distance traversed by roller means, and means to display the distance, the measuring device further incorporating manually operable means adapted to add, automatically, to the displayed value a distance equal to the radius of the roller.

The device may be adapted to measure distances in two linear scales, in terms of centimetres and in terms of inches, means being provided to alter the mode of operation of the device from one linear scale to the other linear scale.

The device may include means to enable the measuring device automatically to multiply one measured distance by another measured distance to provide an indication of area.

Preferably the device is provided with two roller means of different outer diameters, the roller means being interchangeably mounted on the measuring device, to enable the measuring device to measure distances of different orders of magnitude.

According to another aspect of this invention there is provided a measuring device for measuring a distance, said device comprising first and second roller means each having an outer periphery adapted to be rolled along the distance to be measured, the first and second roller means being of different diameters, and being interchangeably mountable on the measuring device, means adapted to determine the number of rotations or part rotations of the roller means mounted on the device, electronic means to calculate, from said measured value, the distance traversed by the roller means, and means to display said distance.

Preferably the means to determine the number of rotations or part rotations of said roller means comprise light emitting means, and light receiving means spaced from the light emitting means, there being part of the roller means or an element driven rotationly thereby located between the light transmitting means and the light receiving means, said part being perforated so that as it rotates, pulses of light pass from the light transmitting means to the light receiving means.

Conveniently two light receiving means are provided in staggered positions, thus enabling the direction of rotation of the roller means to be sensed.

The device may be in the form of a hand held battery operated device.

In order that the invention may be more readily understood, and so that the features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which, Figure 1 is a front perspective view of a measuring device in accordance with the invention, Figure 2 is a side view of the device shown in Figure 1, Figure 3 is a vertical section view of the device shown in Figure 2, Figure 4 is a diagrammatic view illustrating the positioning of the light transmitter and light sensors of the arrangement shown in Figure 3, and Figure 5 is a sectional view, to the same scale as Figure 3, showing an alternative form of measuring wheel.

Referring now to the drawings the measuring device in accordance with the invention comprises a housing 1 of elongate form, which is adapted to be grasped manually.

The interior of the housing is hollow and is adapted to contain batteries (not shown) and certain electronic components which will be described hereinafter in greater detail. At one end of the housing a roller 2 is provided in the form of a disc-like wheel, the outer periphery of the wheel being defined by a resilient "0" ring 3 which is received in an annular groove surrounding the wheel.

The outer periphery of the wheel is in an exposed position and the housing is so configured that it may be grasped manually to enable to periphery of the wheel to be brought into contact with the surface to be measured.

As will be described hereinafter means are provided to generate signals responsive to rotation of the wheel to enable the distance traversed by the periphery of the wheel to be calculated.

The housing is provided with a plurality of pushbuttons 4-7, and a liquid crystal display 8.

The push-button 4 is adapted to switch the device on and to clear any information displayed on the liquid crystal display 8. The device is adapted to remain in the on condition while in use, but if the device is not used and no buttons are pressed for a pre-determined period of time, for example, 40 seconds, the device will automatically switch itself off in order to conserve battery power.

The press-button 5 is a multiplying button. If it is desired to calculate an area, it is possible to measure a first distance using the device, namely the width of an area, and then by pressing the button 5 and measuring a second distance, namely the height of an area, it is possible for the display to indicate the area that has been measured.

The push-button 6 is very important, and can be termed a "corner" button. Sometimes it is necessary to measure a distance into a corner. For example, it may be necessary to measure the width of a room from one corner to another corner. It will be appreciated that in utilising the measuring device described above, it is not possible to insert the wheel 2 fully into a corner so that the operative part of the wheel touches the wall precisely in the corner.Thus the key 6 is provided which can be actuated to obviate an error which might otherwise occur. It is to be understood that if the device is held so that the wheel is substantially horizontal, and the measuring device is pressed fully into a corner, so that the wheel touches both walls forming the corner, the operative point of the wheel will con tact the wall to be measured at a point which is spaced from the corner by a distance equal to the radius of the wheel. Thus, when the key 6 is pressed, a distance equal to the radius of the wheel is added to the measured distance as shown on the display 8.

It will be understood that if the length of a wall between two corners is to be measured, initially the wheel will br placed in one corner, the display will be zeroed, and the appropriate key 6 will be pressed to add, to the display distance, a distance equal to the radius of the roller disc 2. Subsequently the measuring device will be traversed across the wall, being pressed firmly into contact with the wall so that the wheel 2 rotates without any slipping occurring until the wheel 2 is pressed into the opposite corner. The key 6 will again be pressed to add to the distance displayed the distance equal to the radius of the wheel 2. The indication provided on the display 8 will then be an accurate measurement of the length of the wall into both corners.

The display may include portions 9, 10 which are illuminated whenever the corner button 6 is pressed so that the operative may readily observe how many times the corner button has been pressed during a specific calculation.

It is to be appreciated that if a distance is to be measured around a corner, that is to say around the inside of a corner, or in other words into a corner along one wall and then out of the corner, on the wall at 900 to the first wall, the key 6 will be pressed twice as the wheel 2 is located in the corner to add to the value displayed a distance equal to two times the radius of the wheel 2.

The button 7 is provided to enable the scale of operation of the device to be altered between inches and centimetres. Again the liquid crystal display 8 may include a portion 11 which is illuminated to indicate precisely which scale the device is operating in at any particular instance.

The liquid crystal display 8 may also include a portion 12 which is illuminated to indicate when the batteries are approaching exhaustion.

Referring now to Figure 3 of the drawings it can be seen that the roller disc or wheel 2 is provided with an annular rearwardly extending flange 13, this flange being provided with a plurality of slits or apertures therein.

The flanged portion of the wheel is located above a printed circuit board 14 contained within the housing 1 on which is mounted the appropriate electronic circuitry.

Also mounted on the printed circuit board is a light emitting diode 15 which is located within the said annular flange 13. Also mounted on the printed circuit board are two photo-sensitive transistors 16, 17 located, as can be seen from Figure 4 and from Figure 3, outside the perforated annular flange, and in a staggered relationship.

The situation is such that as the flange rotates light passes from the light emitting diode 15 through the slits or apertures formed in the flange, to the photo-detectors 16, 17. Since the photo-detectors are staggered, the photo-detectors can determine the direction of rotation of the wheel 2 as each slit or aperture passes between the light emitting diode 15 and the photo-sensors 16 and 17.

Each pulse of light received by the photo detectors 16, 17 corresponds to a pre-determined distance traversed by the wheel, and this distance can be added to a running total held in a memory which forms part of the calculating device which is mounted on the printed circuit board.

Whilst a simple embodiment of the invention has been described, it is to be appreciated that the calculating arrangement, which may be constituted by a microprocessor, may be operable in response to further buttons provided on the exterior of the housing and may be preprogrammed to perform various tasks which may be found useful by a builder, decorator, or handyman. For example, the micro-processor -may be programmed to calculate the number of rolls of wallpaper needed to wallpaper a particular room. In such a case the device may be utilised to measure the outer periphery of the room, and'the height of the room, and an appropriate key pad operation may be performed to determine the number of rolls of wallpaper necessary.

It is envisaged that the described wheel 2 which is a relatively small outer radius may be replaced by a wheel 2' of larger outer radius. The whel 2' is provided with an inwardly directed flange 13', corresponding to the flange 13 described above, and the relatively large wheel may be mounted on the device by removing the small wheel 2 and replacing it with the large wheel 2'. When the large wheel 2' is utilised, the device may be programmesd to provide a direct reading in terms of feet or in terms of metres. The large wheel may be provided with means adapted, in use, to engage a micro switch or the like mounted on the printed circuit board, or some other sensor, so that the calculating device may be appropriately re-programmed to provide an accurate indication of distances traversed in terms of feet or metres.

Claims

1. A measuring device for measuring a distance, said device comprising a roller means having an outer periphery adapted to be rolled along the distance to be measured, means adapted to generate a signal indicative of the number of rotations or part rotations of said roller means, electronic means to calculate, from said measured value, the distance traversed by roller means, and means to display the distance, the measuring device further incorporating manually operable means adapted to add, automatically, to the displayed value a distance equal to the radius of the roller.

2. A measuring device according to Claim 1 adapted to measure distances in two linear scales, in terms of centimetres and in terms of inches, means being provided to alter the mode of operation of the device from one linear scale to the other linear scale.

3. A measuring device according to Claim 2 adapted to measure distances in terms of centimetres and in terms of inches.

4. A measuring device according to any one of the preceding claims including means to enable the measuring device to multiply one measured distance by another measured distance to provide an indication of area.

5. A measuring device according tp any one of the preceding claims being provided with two roller means of different outer diameters, the roller means being interchangeably mounted on the measuring device, to enable the measuring device to measure distances of different orders of magnitude.

6. A measuring device for measuring a distance, said device comprising first and second roller means each having an outer periphery adapted to be rolled along the distance to be measured, the first and second roller means being of different diameters, and being interchangeably mountable on the measuring device, means adapted to determine the number of rotations or part rotations of the roller means mounted on the device, electronic means to calculate, from said measured value, the distance traversed by the roller means, and means to display said distance.

7. A measuring device according to any one of the preceding claims wherein the means to determine the number of rotations or part rotations of said roller means comprise light emitting means, and light receiving means spaced from the light emitting means, there being part of the roller means or an element driven rotationly thereby located between the light transmitting means and the light receiving means, said part being perforated so that as it rotates, pulses of light pass from the light transmitting means to the light receiving means.

8. A measuring device according to Claim 7 wherein two light receiving means are provided in staggered positions, thus enabling the direction of rotation of the roller means to be sensed.

9. A measuring device according to any one of the preceding claims in the form of a hand held battery operated device.

10. A measuring device substanture as herein described with reference to and shown in Figure 1 to 4 of the accompanying drawings.

11. A measuring device substanture as herein described with reference to and as shown in Figure 1 to 4 of the accompanying drawings as modified by Figure 5.

12. Any novel feature or combination features disclosed herein