GB2222677A - Levelling device - Google Patents

Abstract

A level in which a closed liquid-filled bowl 4 made of a transparent material contains a liquid having an air bubble 7 of small size floating therein, said liquid-filled ball being fixed inside a tubular casing 3 with a white fixative 6, and a strongly coloured band 13 is attached to the outside of said liquid-filled bowl, and wherein said colour band is formed of a strongly coloured band-like ring separate from both said liquid-filled bowl and said tubular casing, and interposed between said liquid-filled bowl and said tubular casing. The coloured band 13 causes the bubble 7 to be high-lighted for ease of viewing. A miniature electric bulb may also be installed to improve the viewing of the bubble. <IMAGE>

Description

LEVELLING DEVICE The disclosed invention relates to levelling devices used to level apparatus, such as electronic balances installed in stores such as supermarkets and perishable food shops and employed to measure the weight of goods, and to maintain them on a level during measurement.

It is necessary in many cases that devices such as electronic balances and measuring devices are used when exactly level in order to obtain accurate results.

If such devices are frequently moved and replaced over a period of time, or are operated in such conditions that the devices are inevitably subject to vibrations or swings from the surroundings, a detection mechanism is often required to level the devices during normal use and then to maintain them in that state. It is also highly desirable that the detection mechanism have a simple structure, low cost and high durability.

A small spot type level, according to the prior art, is shown in Figure 1 (note that Figure 1 is a cut-away view in which an enclosed liquid-filled bowl or ball made of glass or the like is fixed inside a tubular casing 3, which is made of synthetic resin or the like and has a mounting flange on its upper portion, with a white fixative 5 such as plaster completely filling the space below the liquid-filled bowl. A small air bubble 7 floats in a liquid 6, such as alcohol or water, enclosed in the liquid-filled bowl 4, so that the air bubble 7 may visibly move dependent on the behaviour of the liquid-filled bowl 4.A coloured circular detection ring 8, preferably black or blue, is provided on the liquid-filled bowl 4, so that displacement of the air bubble 7 relative to the ring 8 can be visually checked from above to detect inclination of the level 1, and hence the inclination of a device such as an electronic balance to which the level 1 is attached. For example, as shown in Figure 6, the level 1 is set into the outer surface of a device 9 such as an electronic balance, or as shown in Figure 8, it is attached to an inner bracket 10 of a device 9'.In either case, displacement of the air bubble 7 with respect to the ring 8 is checked visually from above the upper surface of the device 9 or through a window 11 (provided with a glass sheet or the like as required) in the upper surface of the device 9', and then adjusting screws 12, 12... disposed at four corners or so of the device 9, 9' are turned so as to position the air bubble 7 in the center of the ring 8, thereby levelling the device 9, 9' for the intended operation.

Because the level 1 of this type is normally small in size, as shown in Figure 7, visual checking is not easy. If the level 1 is set in the upper portion of the device 9, it is possible to visually check the position of the air bubble 7 with respect to the ring 8 with relatively ease under ambient lighting conditions around the device 9 on which the level is set, and hence to turn the adjusting screws 12, 12 to level the device 9. However, if the level 1 is set inside the device 9' as shown in Figure 8, ambient lighting is not sufficient to illuminate the interior of the device 9', and outside light will be interrupted if the operator attempts to check the air bubble visually with his head above the window 11.Hence it is difficult to check the position of the air bubble 7 with respect to the ring 8 visually, thereby resulting in difficulties in adjustment of the level of the device.

To cope with this problems, a level as shown in Figures 4 and 5 has been developed and put into use. In this device, a liquid-filled bowl 4' set in a tubular casing 3' of a level 1', shown in Figure 5, has on its neck portion a strongly coloured band 13 formed by painting or bonding paint, ink, tape or the like in a strong colour such as red. The air bubble 7 becomes coloured in light reflected from the colour band 13 and contrasts with a white fixative such as plaster which fills the tubular casing 3' below the liquid-filled bowl 4', thereby making it possible to visually check the position and behaviour of the air bubble 7 with respect to the ring 8 even under the relatively dark outside light as experienced when the level 1' is set in the interior of the device 9' as shown in Figure 8.

However, since the level 1' has a relatively small size as mentioned above, it is very difficult to set the liquid-filled bowl 4 in the tubular casing 3 and fix it in place using the fixative 5. In addition to this drawback, the operations of painting or bonding the deep colour band 13 to the neck portion of the liquid-filled bowl 4' are very time-consuming, which results in increased cost. Another drawback is that the painted or bonded color band 13 may sometimes be damaged or scraped during the process of setting the liquid-filled bowl 4' in the tubular casing 3, and the outline of the air bubble 7 may lose sufficient distinctness against the background of the reflected light.

Consequently, the set up and assembly of the level 1' requires a highly experienced skilled operator and mass production is prevented by this.

It is an aim of the present invention to provide a spot type level and which can be set in a device such as an electronic balance, has a simple structure, can be assembled at a low cost, is free from any defects and highly durable, and in which the air bubble inside the liquid-filled bowl of the level has a clear outline against the background and, can be readily located even in a dark place. Another aim of the present invention is to provide a level which allows the liquid-filled bowl to be set smoothly in a tubular casing during assembly, enables the assembly to be carried out with ease and accurate reproducibility, and assures satisfactory visual checking of the air bubble even in a dark place, without impairing any intrinsic advantages of the spot-type level.

According to the present invention there is provided a level in which a closed liquid-filled bowl made of a transparent material contains a liquid having an air bubble of small size floating therein, said closed liquid-filled bowl being fixed inside a tubular casing with a white fixative, and a strongly coloured band is attached to the outside of said closed liquid-filled bowl, and wherein said colour band is formed of a strongly coloured band-like ring separate from both said closed liquid-filled bowl and said tubular casing, and interposed between said closed liquid-filled bowl and said tubular casing.

The present invention will become further apparent from the following description with reference to the accompanying drawings, in which: Figure 1 is a cut away perspective view of a level embodying the invention; Figure 2 is a cross-section of the level or Figure 1 during assembly; Figure 3 is a perspective view of a colour band as used in the level of Figures 1 and 2; Figure 4 is a perspective view of a level according to the prior art; Figure 5 is a perspective view of a fluid filled bowl to be set in a level according to the prior art; Figure 6 is a cut away side view of a device, such as a weighing scale, showing a mounting position of a level; Figure 7 is a cross-section of the level according to the prior art; Figure 8 is a cut away side view of a device showing an alternative mounting position for the level.

In one embodiment of the present invention there is provided a level 1" which is fixed using the bracket 10 at a predetermined position inside a device, such as an electronic balance 9', as shown in Figure 8. A tubular casing 3" made of a suitable synthetic resin has, integrally formed in its upper portion, a flange 2', and on its opposite lateral sides a pair of elastic hooks 15, 15.

The flange 2 and the elastic hooks 15, 15 cooperate to hold the level in its mounting position.

A bowl 6, made of glass or a similar material, is filled with a liquid, such as water or alcohol and a small air bubble 7 of a particular size is sealed therein so as to float in contrast with the upper, slightly domed, closure of the bowl. A circular ring 8, used as a reference for locating the air bubble 7, is defined on the upper surface of the liquid-filled bowl 6 using suitable ink of a colour such as black or blue.

There is also provided a coloured band 13' which is made of a suitable material, such as paper, synthetic resin or metal, and which is strongly colourea, for example in flourescent red or orange, on both its inner and outer surfaces. A vertical slit 14 is formed in a portion of the band-like ring 13', allowing the latter to be pressed into contact with the upper inner surface of the tubular casing 3" by virtue of its own elasticity in its initial set-up state, when the band-like ring is interposed between the upper inner surface of the tubular casing 3" and a neck portion of the liquid-filled bowl 4".

After the liquid-filled bowl 4" has been placed in the upper portion of the tubular casing 3" with the band-like ring 13' interposed therebetween, a fixative 5' such as white plaster is squeezed out of a tube 16 and fills compactly the space below the liquid-filled bowl 4" at the bottom of the tubular casing 3", as shown in Figure 2, and thereby fixedly sets both the members.

In the above construction, when inserting the band-like ring 13', coloured fluorescent red, and the liquid-filled bowl 4" in the tubular casing 3", the band-like ring 13', coloured fluorescent red, is first compressed with the aid of the slit 14 and inserted in the tubular casing 3" so that it is positioned while being held in contact with the upper inner surface of the tubular casing 3" by the force of its own elasticity, as shown in Figure 2. Then, the liquid-filled bowl 4" containing a floating air bubble, is inserted into the band-like ring 13' from beneath such that its neck portion locates within the band-like ring 13'. Next, the white plaster 5' is squeezed out of the tube 16, and fills the space below the liquid-filled bowl 4", in the lower portion of the tubular casing 13" to fix them in place.

Finally, the tubular casing 3" is attached inside the device 9' by engaging the flange 2' with the internal bracket 10, whereupon mounting of the level 1" is completed.

In practical use, the position of the air bubble 7 inside the liquid-filled bowl 4" of the level 1" is visually checked through the window 11 in the upper surface of the device 9'. Although little ambient light is able to reach inside the device, and hence the interior of the device 9' is rather dark the fluorescent red colour of the band-like ring reflects even the small amount of light passing through the window 11 and clearly highlights the outline of the air bubble 7 in the liquid 6, thereby making it possible to see the position of the air bubble 7 with respect to the ring 8 with certainty when viewing from above through the window. While performing such a visual check, adjusting screws 12, 12... are finely adjusted to correct the inclination of the device 9' prior to use.

Alternative embodiments include for example, colouring the ring 13 in other colours such as orange or blue. Further, when the level is positioned inside a device, a miniature electric bulb may be installed on the device at a predetermined position.

As an alternative method of construction the liquid-filled bowl 4" may be set in place prior to insertion of the band-like ring 13' in the tubular casing 2". This will not alter the function of the band in clearly highlighting the air bubble 7 in the light reflected from the band-like ring 13' of the level 1" thus assembled. Thus, the order of insertion of the band-like ring 13' and the fluid-filled ball 4" in the tubular casing 3" can be determined according to convenience in the assembly process.

Furthermore, it is a matter of course that the application of the present invention is not limited to electronic balances installed in stores such as supermarkets or perishable food shops, and is applicable to all measuring devices and other machines in place of conventional levels which have been installed thereon. The preferred embodiment of the present invention has the advantages that the band-like ring and the liquid-filled bowl can be easily set in the tubular casing in a simple operation requiring no special skills while assuring improved accuracy with high reproducibility, irrespective of the minute size of the liquid-filled bowl and the tubular casing. Hence mass production of levels and improved reliability is possible.

Because the band-like ring is separate from both the liquid-filled ball and the tubular casing, there is no need to paint or bond a colour band to the neck portion of the liquid-filled ball as with the prior art, whereby the number of steps in construction can be reduced, the possibility of scraping and damage during manufacture can be eliminated and the cost of manufacture is reduced.

Moreover, because the band-like ring is separate from both the liquid-filled bowl and the tubular casing, the band-like ring can be produced in advance as a standard item, which also leads to reduced cost and improved reliability and accuracy of the product.

In addition, the band-like ring can have a relatively large width or height, so long as it remains within the required range of sizes, enabling the amount of reflection of the colour band-like ring to be increased more clearly to highlight the air bubble in the liquid within the liquid-filled bowl.

Claims (4)

1. A level in which a closed liquid-filled bowl made of a transparent material contains a liquid having an air bubble of small size floating therein, said liquid-filled bowl being fixed inside a tubular casing with a white fixative, and a strongly coloured band is attached to the outside of said liquid-filled bowl, and wherein said colour band is formed of a strongly coloured band-like ring separate from both said liquid-filled bowl and said tubular casing, and interposed between said liquid-filled bowl and said tubular casing.

2. A level according to claim 1, wherein said tubular casing is disposed on the surface of a device to be levelled.

3. A level according to claim 1, wherein said tubular casing is disposed inside a device- to be levelled.

4. A level constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 or Figures 1 to 3 and 8 of the accompanying drawings.