FIELD

The invention relates to measuring means for the construction and repair industries, such as by builders, drain-layers, plumbers, home do-it-yourself and in related applications. BACKGROUND

The fluid level is a well-known tool, used in particular by builders in order to set timber framing and many other parts of a building in a fixed angle with relation to the horizon. Versions adapted for measuring slopes may be called "inclinometers". The device is responsive to the pull of gravity, perpendicular to the horizon. Such levels employ a sealed glass or other transparent capsule containing a coloured liquid and a bubble within, to show when the walls of the capsule are horizontal. In fact the reading side of the bubble which is typically provided with transverse indicia is slightly curved outward so that the indication is relatively stable. Commonly, levels are provided with several internal windows, one for perpendicular planes and one at 45 degrees. Most builders know to check the accuracy of a level by reversing the ends to see if the reading is the same.

Prior art having a rotatable wheel for measuring slopes, from which the present invention has been developed, includes Probst (DE 567035 - enclosed pendulum in disk), Kieran (GB 2220267 - floating meniscus inside disk), Resit Sermet (PCT/TR2009/000060- enclosed pendulum disk), Levinson et al (US 7363719 - rim-accessible disk, without axle, with spirit level) and Nichols (US 7152335 - enclosed disk having spirit level).

When a worker wishes to construct a fixture, such as a piece of cut timber or a pipe or a surface to be drained at a slight angle, the level is not an absolute measurement. Sometimes a worker will elevate one end by placing an object underneath it, in order to raise one end relative to the fixture, but this is not calibrated or quantitative, and renders the measurement dependent on surface irregularities under the object. There is therefore a need to provide a version of a level which can be adjusted in some way so that a definite slope or angle typically from zero to 90 degrees can be obtained by use of this version. Also, with respect to the prior art, effective ways to keep the wheel and its surrounds clean and free of dirt should be provided. OBJECT An object of the present application is to provide an adjustable inclinometer or level, or at least to provide the public with a useful choice.

SUMMARY OF INVENTION

A first aspect of the invention provides an adjustable clear view level or inclinometer, comprising a measuring tool comprising an elongated yet straight beam having a longitudinal axis parallel to at least one reference face along the beam, wherein a wheel is rotatably mounted upon a supported shaft and partially enclosed within an aperture intersecting the beam; the shaft being perpendicular to the axis of the beam and parallel with a plane extended from the reference face; the wheel has a thickness and a rim, the rim extending beyond the beam opposite the reference face; the wheel being capable of receiving an externally applied torque applied by a user and assuming a position where it is held by friction imposed by a frictional element; the wheel contains internal gravity direction indicator means having an axis aligned along a chord within the wheel; the indicator means comprising a pre-filled vial having convexly shaped walls and a middle, bearing transverse indicia symmetrically placed about the middle and containing a first liquid and a buoyant object suspended within the liquid; the indicator means being externally visible through a transparent window in order that the position of the buoyant object in relation to the transverse indicia may indicate whether or not the axis of the indicator means is in a horizontal plane; and the aperture includes at least one fixed or axis indicium parallel to the reference face of the beam in close proximity to at least one rotatable indicium located near the rim of the wheel.

In an embodiment, the vial is on an exterior side surface of the wheel. In an embodiment, a plurality of vials are on an exterior side surface of the wheel.

In an embodiment, the periphery of the aperture displays a set of complementary indicia indicating the angle of the wheel; the wheel carries a single indicium parallel with the axis through the length of the gravity indicator, the set of complementary indicia being aligned with reference to the axis indicium.

In an embodiment, the wheel within the aperture displays a set of complementary indicia indicating the present angle of the wheel with reference to the axis indicium. In an embodiment, the scale is repeated on each side of the beam. In an embodiment, the scale is fixedly mounted upon the beam and includes a zero point at which the planar side is horizontal. In an embodiment, the scale is in degrees. In an embodiment, the scale indicates a slope expressed in length and height units, such as centimeters per metre. In an embodiment, the scale includes a vernier scale for finer resolution.

In an embodiment, the pointer is mounted upon the beam and the scale is mounted upon the tiltable support assembly.

In an embodiment, one of the scale and the pointer are provided with trimming means permitting the scale of the tiltable level to be accurately set to zero when the level is horizontal.

In an embodiment, a viewing window is provided that allows the bubble to be viewed from above or from at least one side, or both sides of the tiltable level.

In an embodiment, the elongated yet straight beam is comprised of a clear plastics sheet material. In an embodiment, the straight beam has a rectangular and hollow cross section partially containing the wheel.

In an embodiment, the straight beam has a "T" cross section with the reference face comprising the cross arm of the "T" cross section and the shaft of the "T" cross section partially contains the wheel. In an embodiment, the buoyant object is a bubble within the first liquid. In an embodiment, the buoyant object is a second liquid immiscible with and of a lower density than the first liquid, and having a different colour to that of the first liquid.

In an embodiment, the adjustable clear view level or inclinometer is formed using injection moulding techniques. In an embodiment, one of the scale and the pointer are provided with trimming means permitting the scale of the tiltable level to be accurately set to zero when the level is horizontal. In an embodiment, the motion of the support assembly is provided with detents at fixed points such as set fractions of a circle, so that it can be returned to any one of those fixed points with ease.

In an embodiment, a small wheel or lever engaging with a side of the support assembly is employed to transfer an adjusting force from the exterior to the support assembly.

In an embodiment, a worm screw drive, turned by means of a hand wheel, is turned against a cut thread around the exterior of the support assembly in order to transfer an adjusting force from the exterior to the support assembly. In an embodiment, the pitch of the worm screw drive corresponds to one turn per degree or some other convenient amount.

In an embodiment, the wheel is turnable inside a fully enclosed yet transparent housing, while an exposed knob or handle upon a shaft extended through a sealed orifice is used from time to time to turn the wheel.

In an embodiment, the handle is also used as a pointer, to transfer a direction on to a scale attached to the beam of the level.

In an embodiment, a magnifier is included over a reference indicium.

In an embodiment,, draining or cleaning means is provided so as to allow any foreign materials to be removed.

In an embodiment, the entire assembly may be taken out of the aperture after removing at least one viewing window and cleaned.

In an embodiment, two separately rotatable wheels are frictionally mounted on to the beam, each wheel containing or bearing an internal gravity direction indicator means.

A second aspect of the invention provides a method for using the level described above, wherein the measuring tool is placed on a surface that is to be measured having an undetermined incline, the wheel is forcibly rotated by a user against the frictional element, thereby overcoming static friction, so that the floating object within the tube is aligned with respect to the horizon; whether seen from a side of the beam or from the face thereof, and the slope of the inclined surface is determined by reading the markings on both the rim of the wheel and on the beam that are in closest proximity. In an embodiment, the slope of the measured surface is retained as a particular orientation of the wheel after the level is removed from the surface that is to be measured.

Throughout this specification unless the text requires otherwise, the word "comprise" and variations such as "comprising" or "comprises" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. Each document, reference, patent application or patent cited in this text is expressly incorporated herein in their entirety by reference. Reference to cited material or information cited in the text should not be understood as a concession that the material or information was part of the common general knowledge or was known in New Zealand, Great Britain or in any other country.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

DRAWINGS

Fig 1 : shows a diagrammatic orthogonal view of a level according to an embodiment of the invention.

Fig 2: shows detail of one version of the adjustable portion of the level of Figure 1.

Fig 2a: shows a top view of the wheel or disk insert region of the level of Figure 1.

Fig 2b: shows one possible design for a transparent window and disk axle support of the level of Figure 1.

Fig 2c: is a vertical section through an axle of a fully enclosed version of the wheel of the level of Figure 1.

Fig 3 : shows a rotatable wheel or disk, with applied finger.

Fig 4: shows a rotatable wheel and associated fixed indicia including a protractor.

Fig 5 : Exploded view of a rotatable wheel.

Fig 6: shows details of a rotatable wheel.

Fig 7 is a diagram of a T-outline beam level in cross-section.

Fig 8: shows a level having a rotatable wheel and associated fixed indicia, indicating rotating protractor.

Fig 9: the level of Fig 8 on a slope, after adjustment of the wheel. Fig 10: is a diagram of another T-outline beam level in elevation view.

Fig 11 : is a diagram of a modified T-outline beam level.

Fig 12: is a diagram of the level of Example 5.

Fig 13a: is a plan diagram of the level of Example 6.

Fig 13b: is an orthogonal view of the level of Example 6.

EXAMPLE 1

See the diagrams of Fig 1, showing an overall view, and subsequent illustrations showing details and alternatives. This invention uses conventional liquid-based vials as gravity direction sensing means, within which an internal bubble or other less dense, immiscible fluid is located midway along the vial when the length axis of the vial is horizontal. The consistent principles of this invention which is a builder's level 100 for evaluating horizontal or sloping planes between 0 degrees (horizontal) and 90 degrees (vertical), are that a relatively large, transparent wheel or disk 107 incorporating a liquid bubble container 108 is rotatably inset into the beam 101 comprising the body of the level, and the edge of the wheel (in most examples) protrudes from a face 103 opposite to a reference (contact) face 106 of the beam. The wheel can be tilted to a known amount in relation to the planar side and in an axis perpendicular to the length of the beam, using either direct contact (Fig 3) or an intermediate wheel 117 as in Fig 2 Figs 8 and 9 show a level before and after a measurement in which the wheel has been rotated back to a "vial is horizontal" attitude after being supported on an incline 901. Adjustment of the wheel by rotating it upon a supported axle 113 to centre the bubble 116 when the level is upon a test slope comprises a deliberate measurement action. A factional mount holds the wheel in position after turning. For example, a washer made of a fibrous material such as felt (on each side of the wheel in between an axle support and the wheel provides friction.

The inventor considers that the advantages of supporting the wheel or disk upon a central axle as compared to the rim- supported wheels of the prior art outweighs any disadvantages arising from a need to provide actual supports (fig 2a, 2b, 1001 in Figs 10 and 11, and 1204 in Fig 12) for the axle. For example, the wheel 107 diameter may be significantly larger than the height of the beam (from 103 to 106) of the level. A large wheel allows better setting and reading accuracy yet at a low cost. Also, precise rotation may be applied to the wheel which is referenced to an axis within the body of the level. Prior art levels held the wheel by its rim.

The amount of slope is quantified by noting relative positions of a rotatable mark or pointer 119 around the wheel rim in relation to a number of fixed marks 112 at specific degree spacings upon the adjacent beam 106. The array of marks 112 is fixedly mounted upon the beam and includes a zero point at which the planar side is horizontal. Preferably the scale is in degrees, and is reproduced on each side of the beam 101 of the level. This drawing shows one point for every 2 degrees of a circle. Optionally the scale indicates a slope expressed in length and height units, such as centimeters per metre, or feet per mile, such as for railway engineers. Alternatively, the number of fixed marks may be placed upon the rotating wheel, or a vernier scale may be used on one side. Instead of, or as well as degrees, markings may indicate an amount of rise or fall, such as 1 metre in 100. The scale as shown in Fig 2 has not been enhanced such as by making every 5th mark larger, for ten degree increments. Any readability enhancement is useful and is consistent with the inventor's intent of providing a useful and accurate level. Fig 10 uses 15 degree spacings.

The version shown in Fig 1 includes a bubble vial or container 104 preset for horizontal surfaces and another container 105 preset for vertical surfaces. Although a single rotatable vial or container is sufficient for most purposes, Example 5 has two. Fig 2 shows the measurement section 111 in more detail. Note that the liquid-based vial or container is mounted along a chord within the wheel, near to but not in physical contact or conflict with the axle. In this illustration the wheel 107 is enclosed within a protective cover 109, and is moved by means of a frictionally coupled thumb wheel 117, as a measure to combat ingress of dirt into the space between wheel 107 and a surrounding space. In most versions it is intended that the wheel 110 is available for contact with the user's finger or thumb, as in Fig 3.

Fig 2a shows a plan view section across the level passing through axis 113. The axle 1 13 is preferably supported on a transparent support enclosing the sides of measurement section 111. Two felt washers 114 are shown, as one way to provide static friction that prevents the wheel 107 from spinning freely and to hold it wherever the user sets it. Cork or another material having suitable factional characteristics may be used instead. Another way to prevent the wheel from spinning freely is to tighten a locking screw 118 as shown in Fig 2, after the level has been placed upon a surface to be assessed and the wheel 107 has been turned so that bubble 116 inside vial 115 lies symmetrically between indicia 115. This drawing includes the window assembly 109 as shown in Fig 2b.

Fig 2b shows one example combination window, housing, and axle support 109, made from a U-shaped piece of transparent plastic including an access hole 120 for contacting the wheel rim, window support screw holes 201, and axle support holes 113. This piece may be moulded. It may screw, or clip on with spring pressure on to the shaft 101 of the level, and its removal from time to time may allow the wheel and its housing to be cleaned or drained. The shaft may include a recess so that the sides of the support 109 are flush with the sides.

One way to provide better resolution of slope is by incorporating a Vernier scale (not shown) upon the element that moves in relation to the main or protractor- like scale. This scale allows safer interpolation between marked indicia, as is well known in the relevant arts. In an option the pointer is mounted upon the beam and the scale is mounted upon the tiltable support assembly - see Example 2.

Optionally either the scale or the pointer are provided with mechanical trimming means permitting the scale of the tiltable level to be accurately set to zero when the level is horizontal. A user can check a level by ensuring that the same reading is obtained whether the length of the beam is in one direction or is swung through 180 degrees. Such trimming might be done at a service centre only. Alternatively the level is made correct in the first instance - see Example 2 and Fig 6.

For convenience, the motion of the support assembly may be provided with perceptible detents at fixed points such as set fractions of a circle such as 0, 22.5, 30, 45 and 60 degrees in either direction, so that it can be returned to any one of those fixed points with ease.

One must allow for the possibility that no scale is required. An ability of the support assembly to be tilted to a specified angle during use is required. The tiltable level is set upon a precisely tilted surface, normal to the slope of course, and adjusted while upon that surface so that the bubble 116 inside the sealed container 115 is centered between the indicia 112; the arrangement of Fig 2 being non-limiting. Then the device can be taken lifted off the slope and read or used on a unknown slope, since it holds the slope reading. On a large construction site, providing a tilted reference surface for use when setting construction planes such as for draining of impervious surfaces might be the responsibility of a senior person.

As an alternative for the small thumb wheel 1 17, a worm screw drive (not shown), turned by means of a hand wheel, is turned against a cut thread around the exterior of the support assembly in order to transfer an adjusting force from the exterior to the support assembly. In one option, the pitch of the worm screw drive is set to correspond to one turn per degree or some other convenient amount.

A version for which the wheel is fully enclosed in shown in Fig 2c, which is a vertical cross-section through a wheel 107 and its axle 203. The versions described elsewhere in this Section have a partially exposed wheel; the remainder of which is inside a housing. It will be appreciated that builder's levels may be used in contact with sand or wet cement and gross contamination is likely. In Fig 2c, a rotatable knob and/or pointer 204 is fixed to an exposed end of the axle 203, which protrudes from an enclosed space inside cover 109 through a seal represented in this diagram by two circular sections through an O-ring 205 or similar resilient material. That seal prevents ingress of water or dust or sand or the like. The axle terminates in a recess at the left side of the drawing, beside label 203. The wheel is fully enclosed by cover 109 above, and by the body of the beam of the level, not shown here. In order to adjust this wheel, the user grasps or nudges the pointer or knob 204 and rotates it so that the bubble within vial 108 lies in the centre of the vial. Either that pointer 204 or a pointer as 303 in Fig 3 now indicates the slope in degrees. Felt pads 114 are preferred as friction-generating means over friction developed against the O-ring. In order to prevent the axle from being inadvertently pulled out of the cavity inside 109, it may be necessary to add a retaining washer which is fixed to the shaft adjacent to seal 205, or to fix the axle within wheel 107 either by glue or by tightening a set screw (not shown) once the axle and wheel are in place.

Fig 3 shows a wheel 301 rotatable by an applied force such as by the finger above. The rotational wheel can be mounted on an axis on or lifted above the top plane of the level, permitting the use of a larger wheel and correspondingly greater calibration precision with large easy to read characters. While Fig 2 shows a cover 109 over the wheel, this may be deleted as in Figs 3, 8, 9, and 10. Not shown here is means to clear dust, sand, and the like out of the space between the rotating wheel and the outer window. For instance the axle 113- 113a of Fig 2a may be made of a pair of screws each with a countersunk head that screw into each other, a method well-known in the engineering arts. These screws penetrate the sides of a U-shaped clear plastics housing 109 formed so as to fit over a narrowed part of the level 102 into which the wheel is inset. One of these screws 113/a may be turned in relation to the other to tighten, loosen, or remove the wheel. Draining means may be provided so as to allow any water to be released. The same adjustment is used to tighten or loosen the grip of the housing 109 upon the felt washers 114, 114 that provide a factional grip on the wheel. It will be appreciated that there should be little or no play of the wheel upon its axle 113- 113a.

Examples of calibration marks 302 over a range of 0 to 90 degrees are shown. These can be displayed in one quadrant as 0 to 90 and in the adjacent quadrant as 90 to 0 degrees. This permits readings where required when the angle is in the perpendicular. Otherwise the readings can be 0 to 90 degrees (ascending) on one side of the level and on the opposite side the quadrants reading 90 to 0 degrees (descending). The viewing window 303 is optionally a modular or integral part of the level, constructed with materials that permit a view of the spirit bubble from above and / or either side of the level. Note that indicia would be usually be placed on both sides.

Fig 4 shows a dual indicating rotating protractor type of scale. The needle 401 is coloured (say red) and the corresponding calibrations (outer) 402 are red and thus describe the current angle between the wheel and the axis of the beam of the level. The second needle 403 is black and the relevant calibrations to this indicator are also in black 404 each being in reverse order to permit dexterous usage. The bubble vial 405 has a symmetrical dilation in its centre and can be accurately read either at zero or after rotation through 180 degrees, to defines the angle from the upright or inverted aspect. Figs 8 and 9 illustrate a level (Fig 8 at 100) with a rotatable wheel 107 including a bubble vial 108 and fixed 112 and movable 119 indicia that is on a level surface in Fig 8 and has been placed on an inclined surface upon a mass 901 in Fig 9. The user has not rotated the wheel so that the bubble inside the vial is again centrally placed between the marks. Fig 10 shows a conversion of a cube-like beam level (such as 100 in Fig 8) into a shaped device (1000 in Fig 10). As before, this device includes a wheel 107 supported on an axle 113 upon a trunnion 1001 ; one on each side) which are preferably clear so that the movable indicia 119 can be seen through them, and has a reference surface 106 beneath a body 101. This level may have an upside-down "T" cross-section like that of Fig 7 - see below. The reference surface may carry ruler markings such as in centimeters. This device may be of use for hanging pictures or other do-it-yourself tasks.

EXAMPLE 2

The gravity-indicating wheel is amenable to manufacture in volume. One alternative method of manufacture is to make a wheel having a blind aperture elongated along a chord by injection moulding a disk. The die includes a projection that impresses the elongated aperture. The aperture is dimensioned so that a bubble vial will be a press fit within, when the disk has cooled. Then the vial is held in place by, for example, glue. Or the elongated aperture may include on its centripetal aspect a spring-like shape for resilient retention. Co-moulding a vial inside an injection-moulded wheel of a thermoplastics material involves techniques and methods well known to those skilled in the art, but the vial contents should be suitably heat-resistant. Other apertures may be included within the wheel, like spokes, to save materials.

Fig 5 is an exploded view of a wheel made from a layered assembly of disks 501 and 502 of a transparent plastics material each having a central aperture for an axle. The thicker disk 502 is includes a vial outline 504. (The drawing has not included the effects of refraction on the outline as seen through the edge of the disk). It may be convenient to form a series of indicia matched to the alignment of the simulated vial at the same time, such as peripheral cut or impressed marks 512 (see Figs 10 and 11). These marks may be filled with a pigment or paint during manufacture, for easier viewing. Fig 6 shows the face view of a wheel 502, including a vial 509, a central aperture for an axle at 1 13, and a series of markings around the periphery. In this Example the lower part of the wheel at 502a is shown as a more intensely hatched area to reflect the possibility that it is made of a non-transparent plastics material. EXAMPLE 3

The material of the body 101 of the level 100 is typically metal, such as an extruded and powder-coated aluminium. In one option the body of the level is comprised of a transparent (water-clear) plastics material such as, but without limitation, acrylic sheet or an extruded plastics material. The reference surface 106 may be an added metal surface. Further, although the body 101 of the level is shown in Fig 1 as a box-section rectangular tube, it may be a "T" shape as shown in Fig 7 (cross-section) which saves material. In those versions it is advantageous for the rotatable wheel (protruding portion 703 shown) to be thin because it is mounted within the shaft 701 of the "T" and upon the base 702. Figs 10 and 11 are also "T" section levels.

EXAMPLE 4 As an option, the level may have the protractor-like indicia (0-90-0 degrees) marked on the wheel, and at the same time the or each triangular trunnion which supports the shaft is moulded so as to include a raised curved clear plastics part above a zero reference mark made underneath the trunnion. This is shown at 1101 in the tilted level in Fig 11, which has been adjusted while upon an about 30 degrees slope to set the vial within in a horizontal axis. The refractile nature of the plastic "bulge" results in a magnifying-glass effect that makes the scale easier to read. The bulge may be cylindrical (with an axis directed toward the wheel axis), elliptical or circular.

EXAMPLE 5

A dual wheel level 1200 may be provided, as shown in Fig 12. In this, both wheels 1201, 1202 are preferably located side by side within a transverse aperture across the beam of the level. Both wheels share a common axle 1203 fixed to a median septum 1204 within and parallel to the length of the beam of the level, while each wheel is separately rotatable against a suitable frictional surface such as a felt washer as described elsewhere in this section. The purpose of a dual level is to permit up to two different slopes to be "remembered" by orientation of the respective wheel. The two wheels may be placed at different positions, in different apertures, along the length of the beam.

EXAMPLE 6

Figs 13a (top view) and 13b (from an angle) show a version of the level which is consistent with the principles of the invention in that it has a large wheel 1304 mounted on an axle 1 13 within an aperture passing through a beam 1300. The axle is supported on two preferably transparent strips 1301 that traverse the aperture by, for example, screws and again uses a friction pad of felt or cork or other material having suitable frictional characteristics to hold the wheel in place unless it is being rotated by finger contact with the exposed edge. The wheel supports a spirit vial 1302 to the side of the wheel. Unlike previous Examples the vial is securely mounted outside the disc of the wheel. The vial is inside a plane projected from the side walls of the beam and is protected by the strips 1301. In this case, an optional second vial 1303 mounted perpendicular to the first is also included, by way of example. Degree markings 1305 on the exterior of the beam and spaced apart by 10 degree intervals (for instance) are carried through the depth of the aperture so that the position of a rotatable indicium can be read. One advantage of this Example is that dirt and contamination can be removed easily.

RESULTS AND ADVANTAGES

Readability: Although the overall dimensions of the level conform to conventional design, the diameter of the wheel has been made as large as reasonably possible and has been optimised for readability of the indicia. Accuracy: Since as large a liquid- filled level- indicating container as possible is employed, the level provides better discrimination of the horizontal Since the wheel rotates upon a central axis aligned with fixed and movable indicia, the pointing accuracy of the scale is maximized.

Materials: Materials may be selected according to cost, working lifetime, and durability as previously discussed. The invention allows material consumption to be minimised.

Finally it will be understood that the scope of this invention as described and/or illustrated herein is not limited to the specified embodiments. Those of skill will appreciate that various modifications, additions, known equivalents, and substitutions are possible without departing from the scope and spirit of the invention as set forth in the following claims.