GB2285507A

GB2285507A - Apparatus for establishing a horizontal level or a desired slope

Info

Publication number: GB2285507A
Application number: GB9400191A
Authority: GB
Inventors: Michael Edward Luton
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-01-07
Filing date: 1994-01-07
Publication date: 1995-07-12
Anticipated expiration: 2014-01-07
Also published as: GB9400191D0; GB2285507B

Abstract

To establish a level or a desired slope one end of a line 4 carrying a level indicator 5 is fixed at a reference point, the other end of the line is positioned at a point remote from the reference point and the line at the remote point is moved either upwardly or downwardly in response to the indication given by the level indicator to establish the level or the desired slope of the line. The line may be stored on a spring spool 3 and may be in the form of a tape. The level indicator may be a spirit level or a pendulum level. <IMAGE>

Description

"A method of and apparatus for establishing a horizontal level or a desired slope This invention relates to a method of and apparatus for establishing a horizontal level or a desired slope and more particularly to an instrument for providing an indication of a horizontal level.

There are many problems associated with the use of known spirit levels for establishing a horizontal level from a reference point to a second point. In particular, if the reference point and the second point are a large distance apart, then the spirit level cannot span the distance between the two points. It is therefore necessary to mark the horizontal level using a number of intermediate points. This leads to an accumulated error which might be as much as 5cm over a 5m span. Additionally, it is difficult to take accurate measurements if there is no medium between the reference point and the point to be levelled with reference to the reference point such as a flat and vertical wall. In many cases, there are obstructions between the reference point and the second point such as window sills, cupboards, power points or the wall may not be true leading to further measurement errors.

Additionally, spirit levels are precisely machined articles which are inherently expensive.

When marking tiles or fixing kitchen cabinets over a large distance, it is known for builders and kitchen fitters to use water-lines which are long transparent hollow tubes filled with a predetermined amount of water.

Graduations are provided on the outside surface of the tube and the water-line works on the principle that the level of the water at both ends of the tube will be identical.

However, water-lines are lengthy and expensive and are prone to puncturing and discolouring, the graduations rubbing off from the outside surface of the water-line thereby rendering the water-line eventually useless. In general, water-lines have a short life span due to the conditions in which they are stored such as on a construction site and in builders' tool bags.

The present invention seeks to provide a method of and apparatus for establishing a horizontal level or desired slope which mitigates the problems associated with both spirit levels and water-lines.

Accordingly, one aspect of the present invention provides a method of establishing a level or a desired slope comprising the steps of: fixing one end of a line carrying a level indicator at a reference point; positioning the other end of the line at a point remote from the reference point; locating the level indicator on the line between the reference point and the remote point; and moving the line at the remote point either upwardly or downwardly in response to the indication given by the level indicator to establish the level or the desired slope of the line.

In another aspect of the present invention there is provided an apparatus for establishing a level or a desired slope from a reference point to a point remote from the reference point comprising a line for extending between the reference point and the remote point and a level indicator adapted to be carried by the line and locatable on the line between the reference point and the remote point.

A further aspect of the present invention provides a level indicator comprising an outer envelope substantially filled with a liquid to create a bubble within the outer envelope, a substantially straight level indicating surface and a passage passing through the outer envelope substantially parallel to the level indicating surface, the level indicator being provided with a means for indicating the angular displacement of the level indicator.

Another aspect of the present invention provides a level indicator comprising an outer envelope substantially filled with a liquid to create a bubble within the outer envelope, the outer envelope having an arcuate surface along which the bubble moves in response to angular displacement of the level indicator, the level indicator being provided with a means for indicating the angular displacement of the level indicator.

In order that the present invention may be more readily understood embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a partial cross-sectional view of a levelling instrument according to an embodiment of the present invention, a level line being shown partially extended from a housing; Figure 2 is an enlarged, partially cross-sectional view of one form of level indicator used in the levelling instrument shown in Figure 1; Figure 3 shows the levelling instrument of Figure 1 in use; Figure 4 shows another form of level indicator different from that shown in Figure 2; Figure 5 is a partial cross-sectional view of another form of level indicator for use in the levelling instrument shown in Figure 1; and Figure 6 illustrates another embodiment of the present invention.

Figure 1 shows a preferred embodiment of a levelling instrument 1 according to the present invention.

The levelling instrument 1 comprises a housing 2 holding a spool 3 wound with a line 4, the line 4 carrying a level indicator 5. The line 4 may be made, for example, of nylon and is terminated by a plumb 6.

The housing 2 comprises a hollow box, preferably plastics moulded, similar in appearance to a conventional tape measure housing. The housing 2 is formed in two halves 7, 8, only the one half 7 being shown in cross section in Figure 1. The main inside surface of the one half 7 of the housing 2 is provided at about its centre with a spindle 9 which extends therefrom to form an axis about which the spool 3 can rotate. A flat spiral torsion spring (not shown) is located between the spool 3 and the spindle 9 to resist rotation of the spool 3 in the clockwise direction as shown in Figure 1. The line 4 wound around the spool 3 is passed through a pair of guides 10 formed in the bottom right-hand corner of the one half 7 of the housing 2 which guides comprise a datum guide 10.

An opening 11 in the housing 2 is provided in the bottom left hand-corner of the housing 2 opposite the bottom right-hand corner occupied by the datum guide 10.

When extended, the line 4 passes through the opening 11 and is terminated at a solid plumb 6 of conical configuration.

The line 4 between the datum guide 10 and the plumb 6 carries a level indicator 5 which is shown in detail in Figure 2.

Referring to Figure 2, the level indicator 5 comprises a transparent hollow cylinder 12 which is closed at each end by a plug 13. Both plugs 13 are provided with a central bore 14. An inner hollow cylindrical tube 15 is provided which is of smaller diameter than the clear hollow cylinder 12 inside the clear hollow cylinder 12. The hollow tube 15 is held in tight fit engagement within the bores 14 thereby providing a passage through the hollow cylinder 12. The inner tube 15 is parallel to the hollow cylinder 12. The hollow cylinder 12 and the plugs 13 define an outer envelope. The annular space between the hollow cylinder 12 and the inner tube 15 is almost entirely filled with a coloured liquid, the remainder of the space being occupied by air such that a clearly visible air bubble 16 is formed in the hollow cylinder 12. The diameter of the inner tube 15 is dimensioned such that the line 4 can be slidably received therein.

The outer surface of the clear hollow cylinder 12 is formed with, for example, two graduation marks which encircle the cylinder 12. The graduation marks 17 are equally spaced from the centre of the longitudinal axis of the hollow cylinder 12 but are spaced apart such that when the level indicator 5 is horizontal, the bubble 16 extends an equal distance either side of the graduations 17 but when the level indicator 5 is not horizontal, the bubble moves either to the left or right of the two graduations 17. Thus, when the level indicator 5 is horizontal, the bubble 16 sits with either end of the bubble extending equally past the graduation marks 17 thus providing an indication that the level indicator 5 is horizontal.

Referring back to Figure 1, the level indicator 5 is free to move along the length of line 4 between the datum guide 10 and the plumb 6.

In use, the plumb 6 and housing 2 are pulled apart from one another thereby unreeling the line 4 from the spool 3. The pre-loaded spring in the spool 3 maintains a tension in the line 4 so that the line 4 is taut. The plumb end of the line 4 is fixed to a reference point. The plumb 6 can comprise one of a number of attachments such as a clip, an L-shaped flange such as one used on a known tape measure, a loop of line or similar attachment or the line 4 adjacent the plumb 6 can simply be tied around a pipe or the like to establish a reference point from which the horizontal level is to be taken. With the plumb end of the line 6 at the reference point, the housing 2 is pulled away from the plumb 6 until the housing 2 is at or past the point to be levelled with the reference point.The level indicator 5 is slid along the line 4 towards the housing 2 and the line 4 can then be grasped in the fingers of the person making the measurement.

When the person making the measurement lifts their hand grasping the line 4 either up or down, the level indicator 5 being carried on the line 4 between the person's hand and the plumb 6 will be elevated or depressed to an angle above or below the horizontal. The person making the measurement moves their hand up or down until the bubble 16 is seated between the two graduations 17 or until equal amounts of the bubble 16 extend either side of the graduations 17, thus providing an indication that the level indicator 5 and hence that the line 4 is horizontal.

An appropriate marking may be made at the second point to indicate that it is on the same horizontal level as the reference point to which the plumb end of the line 4 is attached. Figure 3 shows a dashed horizontal reference line H running along a wall to which is fixed a first cupboard at the level H. A second cupboard to be fixed at the same horizontal level H is shown being positioned on the level H using the above described method and apparatus.

In the embodiment of the levelling instrument 1 shown in Figure 3, the bottom surface 18 of the housing 2 is machined to be flat and a window 19 is provided in the housing 2 between the datum guide 10 and the opening 11 such that when the line 4 is fully retracted within the housing 2, the level indicator 5 is seated such that it is visible through the window so that the housing 2 and level indicator 5 can be used as a small spirit level.

Figure 4 illustrates another level indicator 5' embodying the present invention. The level indicator 5' comprises a transparent hollow cylinder having a longitudinal axis which is shorter than its radial axis.

The cylinder 5' has two transparent and circular end walls 20, 21 each of which is formed with equi-angularly spaced graduations 17' about its outer periphery, the cylinder 5' and end walls 20, 21 constituting an outer envelope. An inner tube 15' passes through the cylinder from one side to the other side of the cylinder along a chord, which chord does not pass through the central axis of the cylinder 5'.

Thus, when the line 4 is passed through the inner tube 15', the centre of gravity of the cylinder 5', which is approximately at its central axis, is below the chord line through which the inner tube 15' passes, thus causing the level indicator to hang in a stable condition on the line 4 with its central axis horizontal. The cylinder 5' is almost totally filled with a coloured liquid, the remainder of the volume in the cylinder comprising air such that a small air bubble 16' is formed which moves along the arcuate surface of the cylinder 5' into the uppermost portion of the arcuate surface of the cylinder 5'.When the line 4 is horizontal, the bubble 16' is opposite a graduation 17' marked 0 but when the line 4 is angularly displaced upwardly or downwardly, the bubble 16' shifts around the arcuate surface of the cylinder 5' to indicate the angular displacement of the line 4 with respect to a horizontal reference axis. In one embodiment of this level indicator 5', means are provided to prevent movement of the level indicator 5' along the line 4 when the line is vertically displaced.

In a further embodiment shown in the Figure 5, the outer envelope of the level indicator is elliptical rather than circular, the long axis of the ellipse being parallel to the chord line.

Figure 6 shows another embodiment of a level indicator 5'' for use with the present invention which comprises a carriage 30 hooked onto the line 4, the carriage 30 supporting an indicator 31 pivotally mounted on the carriage 30. The indicator 31 comprises a pointed head 32 and a heavily weighted opposite end 33. The carriage 30 carries a plate 34 which is marked with a series of equiangularly spaced graduations 17'' such as those found on a protractor.When horizontal, the pointed head 32 is at rest opposite the graduation 17" showing 0 movement from the horizontal but when the line 4 is angularly displaced, the indicator 31 pivots to maintain the heavily weighted end 33 at its lowest position thus causing the pointed end 32 to indicate the angular displacement on the graduation scale 17''.

An alternative to the embodiment shown in Figure 1 of the levelling instrument according to the present invention comprises a simple length of line 4 upon which is slidably received a level indicator 5 such as that shown in Figure 2.

In a further embodiment of the present invention, the distance between the line in the datum guide 10 and the bottom flat surface 18 of the housing 2 is identical to the distance from the centre of the plumb 6, to which centre the line 4 is attached, to the circular base edge of the conical plumb 6. Thus, the flat surface 18 can be placed on a vertical surface and a vertical reference line can be established when the circular base edge of the conical plumb 6 also touches the vertical surface, the levelling instrument acting as a plumb-line.

The line 4 may also be a metal wire or tape, the shape of the passage 15 being adapted to receive the wire or tape. In one embodiment, the line, preferably in the form of a tape, is provided with a scale so that the apparatus can be used as a tape measure. Further, it is envisaged that the scale can be read through the level indicator 5.

Claims

1. A method of establishing a level or a desired slope comprising the steps of: fixing one end of a line carrying a level indicator at a reference point; positioning the other end of the line at a point remote from the reference point; locating the level indicator on the line between the reference point and the remote point; and moving the line at the remote point either upwardly or downwardly in response to the indication given by the level indicator to establish the level or the desired slope of the line.

2. An apparatus for establishing a level or a desired slope from a reference point to a point remote from the reference point comprising a line for extending between the reference point and the remote point and a level indicator adapted to be carried by the line and locatable on the line between the reference point and the remote point.

3. An apparatus according to Claim 2, wherein the line is wound around a spring loaded spool biassed to wind back any slack line.

4. A level indicator comprising an outer envelope substantially filled with a liquid to create a bubble within the outer envelope, a substantially straight level indicating surface and a passage passing through the outer envelope substantially parallel to the level indicating surface, the level indicator being provided with a means for indicating the angular displacement of the level indicator.

5. A level indicator according to Claim 4, wherein the outer envelope comprises a transparent hollow cylinder and the passage comprises a hollow tube dimensioned to receive a line.

6. A level indicator comprising an outer envelope substantially filled with a liquid to create a bubble within the outer envelope, the outer envelope having an arcuate surface along which the bubble moves in response to angular displacement of the level indicator, the level indicator being provided with a means for indicating the angular displacement of the level indicator.

7. A level indicator according to Claim 6, wherein the outer envelope is elliptical in shape, the long axis of the ellipse being parallel to a passage which extends through the level indicator and is dimensioned to receive a line.

8. A level indicator according to Claim 6, wherein the outer envelope comprises a cylinder having a passage passing through the outer envelope along a chord line of the cylinder above the centre of gravity of the cylinder, which passage is dimensioned to receive a line.

9. A level indicator according to Claim 8, wherein the radial axis of the cylinder is longer than the central axis.

10. A level indicator according to any one of Claims 4 to 9, wherein the means for indicating the angular displacement of the level indicator comprises one or more graduations.

11. A level indicator according to Claim 10, wherein each graduation is provided on the outer envelope of the level indicator.

12. An apparatus according to Claim 2 or 3 including a level indicator according to any one of Claims 4 to 11.

13. An apparatus according to Claim 2, 3 or 12, wherein a housing is provided to accommodate the line and the level indicator in a retracted position.

14. An apparatus according to Claim 13, wherein a window is formed in the housing for viewing the level indicator when located in the housing.

15. An apparatus according to Claim 14, wherein the housing is provided with means to seat the level indicator in the housing in a position in which it is visible through the window, the horizontal position of the level indicator being parallel to a flat surface of the housing.

16. Any novel feature or combination of features disclosed herein.

16. An apparatus according to any one of Claims 2, 3 or 12 to 15 wherein the line is terminated by a plumb.

17. A method substantially as hereinbefore described with reference to Figures 1 to 5.

18. An apparatus substantially as hereinbefore described with reference to and as shown in Figures 1, 3 and 5.

19. A level indicator substantially as hereinbefore described with reference to and as shown in Figures 1 to 5.

20. Any novel feature or combination of features disclosed herein.

Amendments to the claims have been filed as follows 1. An apparatus for establishing a level or a desired slope from a reference point to a point remote from the reference point comprising a line for extending between the reference point and the remote point and a level indicator comprising an outer envelope substantially filled with a liquid to create a bubble within the outer envelope and a passage passing through the outer envelope, which passage is dimensioned to receive the line, the bubble being movable along a surface of the outer envelope in response to angular displacement of the level indicator, the level indicator being provided with a means for indicating the angular displacement of the level indicator, the line passing through the passage and the level indicator being locatable on the line between the reference point and the remote point.

2. An apparatus according to Claim 1, wherein the line is wound around a spring loaded spool biassed to wind back any slack line.

3. An apparatus according to Claim 1 or 2, wherein the surface of the outer envelope is a substantially straight level indicating surface and the passage passing through the outer envelope is substantially parallel to the level indicating surface.

4. An apparatus according to any preceding claim, wherein the outer envelope comprises a transparent hollow cylinder.

5. An apparatus according to Claim 4, wherein the passage passes through the outer envelope along a chord line of the cylinder above the centre of gravity of the cylinder.

6. An apparatus according to Claim 4 or 5, wherein the radial axis of the cylinder is longer than the central axis.

7. An apparatus according to any one of Claims 1 to 3, wherein the outher envelope is elliptical in shape, the long axis of the ellipse being parallel to the passage which extends through the level indicator.

8. An apparatus according to any preceding claim, wherein the means for indicating the angular displacement of the level indicator comprises one or more graduations.

9. An apparatus according to Claim 8, wherein the or each graduation is provided on the outer envelope of the level indicator.

10. An apparatus according to any preceding claim, wherein the line is terminated by a plumb.

11. An apparatus according to any preceding claim, wherein a housing is provided to accommodate the line and the level indicator in a retracted position.

12. An apparatus according to Claim 11, wherein a window is formed in the housing for viewing the level indicator when located in the housing.

13. An apparatus according to Claim 12, wherein the housing is provided with means to seat the level indicator in the housing in a position in which it is visible through the window, the horizontal position of the level indicator being parallel to a flat surface of the housing.

14. An apparatus according to Claim 13, wherein the line is terminated by a plumb and the distance between the line in the housing and the flat surface of the housing is identical to the distance between the point of the plumb to which the line is attached and an edge of the plumb.

15. An apparatus substantially as hereinbefore described with reference to and as shown in Figures 1 to 5.