SPIRIT LEVEL DEVICES
The present invention is concerned with improved spirit level devices, particularly with convenient low-cost spirit level devices.
Spirit levels were invented by Mechisedech Thevenot in the seventeenth century and have undergone little change or development since then. Spirit level devices, more particularly tubular spirit level devices, typically comprise a body upon which is mounted one or more slightly curved glass tubes defining a volume containing a "spirit" (which is typically ethanol), coloured so as to enhance visibility. Other than a gas bubble, the volume is totally filled with the spirit. The spirit therefore typically fills at least 90 or 95% of the volume of the glass tube. Equidistant from the mid-point of the glass tube are provided two spaced apart lines or notches around the circumference of the tube in planes perpendicular to its longitudinal axis. In use, the glass tube is considered to be positioned on a horizontal plane when the gas bubble is located equidistant between the two lines.
Although well established and widely used, such spirit levels are costly to manufacture, even in their cheapest forms, and are bulky and heavy due to the glass tube or tubes.
Currently, enhancements to spirit levels include laser guide devices which incorporate a spirit level and which project laser light to e.g. define a horizontal or vertical line on a surface. However, these are costly, require an electricity supply (typically in the form of batteries) and heavy. Typically, in order to use them, they must be mounted on a wall using pins or suchlike which cause permanent marking. Alternatively, they may be stand mounted. Furthermore, they provide no means for measuring distance, instead just projecting a line of laser light.
Indeed, there is an increasing need (particularly with the growing amounts of DIY and furniture installation being done by individuals at home) for a system which can provide
for measurement of distances on surfaces and for spirit level features without requiring additional support or the assistance of a second person. Indeed, the reality of current spirit level and ruler systems is that in order to create a line on a surface such as a wall at a desired height and angle, a spirit level must first be used to draw a line on a wall at the desired angle. The user can then step back from the wall, assess the line and whether it needs to be higher or lower, and then the cycle is repeated with another line being drawn. When an acceptable line is finally obtained, the wall is typically covered in pencil lines which may have to be removed (which normally results in permanent marking of the wall) and still there are no ruler markings on the line.
The present invention seeks to overcome these prior art disadvantages.
According to the present invention there is provided a spirit level device having at least one body, said at least one body comprising: (i) first and second faces; and
(ii) a periphery joining said first and second faces, and defining between said first and second faces and said periphery a closed volume partially filled with fluid having a meniscus, at least one of the said first and second faces being transparent, and said spirit level device having visible thereon or therethrough at least one alignment marking.
The at least one alignment marking can take a number of forms. Preferably, the alignment marking(s) define an axis through the at least one body. For example, in certain embodiments the at least one marking takes the form of a line or lines or markings defining an axis. Multiple axes through the at least one body can be defined by different markings or sets of markings. So, for example, in certain embodiments a plurality of lines is provided, each line defining an axis through the at least one body. In use, the meniscus is aligned with the at least one marking so that the bottom of the meniscus is generally parallel with the least one marking.
In other embodiments, the at least one alignment marking is provided in the form of a non-linear marking or markings against which the meniscus is aligned. Thus, for example, in certain embodiments the at least one marking is shaped so as to be
complementary to the shape of the meniscus, thus allowing alignment of the whole or a part of the meniscus against the at least one marking - this is in contrast to a single alignment marking in the form of a straight line which in use is aligned only against the bottom of the meniscus. In embodiments shown below, the at least one alignment marking is provided in the form of curved arrowheads, pairs of curves corresponding to the curves of the sides of the meniscus, and not with the bottom of the meniscus. Multiple arrowheads are provided and thus multiple pairs of curves are provided. In use, each of the pairs of curves acts in use to define an axis through the body, that axis being perpendicular to a line that is equidistant from the two curves. Preferably, the axis passes through the intersection of the two curves.
In other embodiments where a plurality of markings are used to define each of a pair of curves, the axis can be considered to be perpendicular to a line that is equidistant from the two (albeit imaginary) curves.
Notably, different portions of the meniscus can be aligned with different portions of the at least one alignment marking, or with different alignment markings.
Thus, by aligning the spirit level device with the at least one alignment marking, it is arranged on an axis through the at least one body. When the spirit level device is arranged on the said axis, it is at a pre-defined angle to the horizontal.
Due to their very simple structure, the spirit level devices of the present invention can be extremely inexpensive and simple to manufacture. For example, in one embodiment (other alternatives are detailed below) a spirit level device may comprise a sheet of an electret with ruler markings and axis markings printed on it, and adhered at opposite ends of it on top of the axis markings two bodies comprising narrow flat-faced 10mm radius discs with a 1-2 mm wide internal space half-filled with a spirit coloured with a fluorescent dye. The sheet thus forms a limb extending from the bodies. Due to the simple and lightweight construction of the bodies, the spirit level can be easily and conveniently adhered to walls and other surfaces by electrostatic force, can go round corners or bends, can be readily re-used, and is inexpensive to manufacture, simply requiring conventional printing processes for the ruler portion and conventional
manufacturing processes for the lightweight bodies. The spirit level device is simple, convenient, accurate and reliable to use, is easy to store, and manufacturing costs can be a fraction of those for conventional spirit levels.
In addition, it overcomes the prior art disadvantages and further allows for the defining of axes around corners or curves. As detailed below, they can be self-supporting, meaning that they can simply be adhered to a wall or other surface by a user who can then step back and assess the positioning of the spirit level and adjust it as necessary without leaving undesired markings on the surface. This ability to be self-supporting is not taught by any of the prior art devices except where they are provided with a stand. Otherwise, the prior art devices require mechanical mounting means to be used to attach them to a surface (e.g. pins or suchlike or strong adhesives) and the failure of the support means can be catastrophic, causing damage to the surface and to the measuring device/spirit level which has fallen from the surface as well as any other objects it contacts. In certain embodiments, the spirit level devices of the present invention can also act as a ruler. Furthermore, multiple devices according to the present invention can be conveniently overlaid, meaning that intersecting axes can be conveniently defined on a surface without the spirit level devices interfering with one another.
In use, the spirit level devices of the present invention take advantage of having a meniscus which is sharply curved (i.e. has a small radius of curvature) in the direction between the first and second faces but which is otherwise relatively elongate. This means that although the meniscus is a continuous curve, it actually has a portion which has a relatively large radius of curvature (i.e. is gently curved) and another portion which has a relatively small radius of curvature (i.e. is sharply curved), and which therefore appears to be generally flat and can therefore be aligned with the at least one marking, e.g. the bottom of the curve can be made generally parallel with a linear marking. This contrasts with conventional tubular spirit level devices whose gas bubbles do not at any point have a large radius of curvature due to their size and the tubular shape of the volume containing them, which defines a volume having a much lower surface area to volume ratio than that of the volume defined by the body of the spirit level devices of the present invention.
Furthermore, preferred embodiments of the present invention include paired markings which are arranged so as to provide a tramline effect, a first one of the pair defining a general line along which a central generally flat portion (i.e. the bottom portion) of the meniscus can be aligned, and a second one defining a line or lines against which the edge portions of the meniscus are arranged (for example so that they intersect the second line(s)).
Preferably, said first and second faces are arranged generally parallel to one another. Of course, if desired, the faces can be at an angle to one another.
Preferably, said first and second faces are generally circular. In certain embodiments it may of course be desirable to have alternatively shaped first and/or second faces and other shapes can be used as desired, for example squares, pentagons, hexagons, heptagons, octagons and other polygons.
The first and second faces are preferably spaced less than 5mm apart, for example less than 4.5, 4, 3.5, 3, 2.5, 2, 1.5 or 1 mm apart. As detailed above, this helps ensure the desired shape of the meniscus.
Preferably the first and second faces are flat on their inwardly facing sides. This can help the appearance to and perception of a user that the meniscus has a generally flat section. Although it is of course possible to have non-flat sides, this may affect the perception of a user of a generally flat portion of the meniscus.
The periphery preferably comprises at least one wall. For example, in embodiments with the first and second faces being circular, the periphery may comprise a single wall. In other embodiments, the periphery may comprise at least two walls.
The body may be fabricated from any desired material. Preferred materials include glass and plastics, and other suitable materials will be readily apparent to one skilled in the art.
The fluid may be ethanol. Alternative fluids will be readily apparent to one skilled in the art, in particular those fluids that are used in conventional spirit levels. Obviously, the choice of fluid may be affected by the materials of the body.
The fluid is preferably coloured, for example with a fluorescent dye. Other colourings and colorants will be readily apparent to one skilled in the art.
Preferably less than 90% of the volume of the at least one body is filled with the fluid, for example less than 85, 80, 75, 70, 65, 60, 55 or 50 % of the volume. Most preferably, about 50% of the volume of the at least one body is filled with the fluid, for example between 45 and 55% of the volume.
Each at least one body preferably has a total weight of less than 10 grams, more preferably less than 9, 8, 7, 6, 5, 4 or 3 grams. Preferably, the at least one body weighs about 3.5 grams.
The at least one body may be circular with a diameter of about 20 mm. The at least one body may have a thickness of less than 5 mm, for example less than 4 mm, for example about 3.5 mm.
Preferably, the spirit level device additionally comprises at least one limb extending from said at least one body. For example, this may be in the form of one or more arms extending from the body.
In a preferred alternative embodiment, the at least one limb comprises a sheet. More preferably, the sheet is rectangular. Suitable materials include but are not limited to papers, plastics, and textiles.
Preferably, the at least one limb is flexible. This can provide for convenient handling and storage of the spirit level device (for example, in the case of a limb comprising a sheet, the sheet can simply be folded or rolled up).
The spirit level device preferably comprises 1, 2, 3, 4 or 5 bodies.
In embodiments where the at least one limb is flexible, it is preferred that the spirit level device comprises at least two bodies. These can be located away from one another, for example at opposite ends of the spirit level device, in order to allow a user to check that all sections of the device are at a desired angle to the horizontal.
The at least one limb (for example a sheet) can be provided in a wide range of forms suitable to a range of applications and uses. For example, the at least one limb can simply extend from the periphery (i.e. an at least one side wall) of the body, e.g. in the form of one or more fingers. Preferably, any limbs which extend from the body do so in pairs, for example as a pair of fingers or arms extending opposite one another from the body at angles to the centre of the body which are 180 degrees apart, thus defining an axis through the centre of the body.
In one preferred alternative form, the body is mounted on the at least one limb. Thus, for example, the body can be provided with adhesive on a (in use) rear face and adhered to a sheet.
As mentioned above, the at least one limb can take various forms, and one preferred form is a ruler. Thus, for example a spirit level device according to the present invention can comprise two bodies adhered to a rectangular sheet having ruler markings upon it.
Suitable ruler markings include metric, imperial/Whitworth, mixed metric and imperial/Whitworth, and reverse (right to left) scales. Registration markings can also be included for combining several spirit level devices, as can markings for use with other products such as laser guides and plumb lines.
As well as providing simple straight rulers, a plurality of limbs can be provided so as to define alternate shapes. For example, the at least one limb may define L, T, X, Y or + shapes, and may be provided with suitable surface markings and suitable located bodies to enable their orientation as appropriate on a surface.
The total surface area of the spirit level device may be at least 100 cm2.
The spirit level device is preferably adapted so as to be self-adhesive to a surface upon which it is to be mounted. This can for example be achieved by way of an adhesive provided on the spirit level device. This could for example be in the form of a single-use adhesive which will no longer be adhesive after removal from a surface on which it has been mounted. Alternatively, the adhesive could be one that retains its properties for a prolonged period over multiple applications.
Preferably, the spirit level device is adapted so as to be self-adhesive by electrostatic force to a surface upon which it is to be mounted. This is preferably achieved by fabricating the spirit level device from an electret. In embodiments where the spirit level device is provided with at least one limb then the at least one limb is preferably an electret. Alternatively, it can be provided with an electrostatic coating. Thus in embodiments where the limb comprises a sheet upon which is mounted the at least one body, the sheet is preferably an electret. Preferable materials for the electret include polypropylenes and polyethylenes. Exemplary electrets include those of US 6284339 and others manufactured by Permacharge Corporation (New Mexico, USA).
The self-adhesive spirit level device preferably also comprises backing material, for example a backing sheet, to which it is reversibly bound. Thus, in use the backing sheet can be removed and the spirit level device adhered to a surface. When use of the spirit level device finished, the backing sheet can be re-adhered and the spirit level device conveniently stored..
Preferably, the at least one marking defines an axis through said at least one body. As discussed below, this is however not necessary since the critical function of the marking is to allow for the alignment of the meniscus, and thus shapes which do not define an axis can also be used.
In various forms of the present invention, it is preferable that the at least one marking is visible on or through said at least one body.
The at least one marking may be in various forms, for example to take advantage of the overall format and structure of the spirit level device. Preferable embodiments for the at
least one marking are at least one line, and at least one notch or indentation. Alternatively, the at least one marking is preferably at least one curve or at least one spot. Thus, the at least one curve or spot can define a shape against which the meniscus can be aligned.
In certain embodiments of the invention it is preferred that said marking comprises at least one line positioned adjacent to said at least one body.
Suitable lines include solid lines, dashed lines, chain-dash lines and suchlike. In certain embodiments, a plurality of lines can be provided, for example 2, 3 or 4 lines. Thus for example four lines can be provided, each at 45 degrees to its adjacent line, and each line passing through the centre of the at least one body, as a result giving lines originating from the centre of the body every 45 degrees.
In those embodiments where the spirit level device is also provided with at least one limb, the at least one limb can be set at a pre-defined angle to the at least one marking, meaning that when the meniscus is generally parallel with the at least one marking the at least one limb (i.e. the longitudinal axis of the limb) is at a pre-defined angle to the horizontal.
For example, a spirit level device can be provided with a body and with a limb in the form of a ruler upon which the body is mounted, the body being provided with markings (lines) at 0, 45, 90 and 135 degrees to the longitudinal axis of the ruler and passing through the centre point of the body, thus also providing lines at 180, 225, 270 and 315 degrees to the longitudinal axis of the ruler. By aligning the mem'scus so that it is generally parallel with one of the markings (for example the 45 degrees line), the ruler is aligned at a pre-defined angle (in this case 45 degrees) to the horizontal.
In other embodiments, only one axis through each of the at least one body need be defined by the at least one marking (for example a continuous line passing through the centre of a body, or a dashed line passing through a body but not through its centre, i.e. defining a chord through the body, or a secant line as an extension of that chord). By providing markings defining only a single axis through each body, a spirit level device
can be provided which will be at a pre-defined angle to the horizontal when the meniscus of the at least one body is generally parallel with the markings. Obviously in embodiments where more than one body is provided, the at least one marking for each body should define axes parallel to one another.
In other embodiments, the at least one marking preferably comprises at least one pair of notches.
As discussed above, a pair of markings may define an axis passing through the centre of the body. More generally, the at least one marking is preferably arranged about the centre of said at least one body and defines at least one axis passing through the centre of the body. Thus the at least one marking can pass through the centre of the at least one body.
However, in other embodiments it is preferable that the at least one marking does not define an axis passing through the centre of the body. For example, in embodiments where the at least one marking is not actually on the at least one body itself but is on a limb (for example a ruler) on which the at least one body is mounted, the mounting process may not be an exact one and as a result the at least one marking may be offset from the centre of the at least one body. In other embodiments it may be intended for the at least one marking to define at least one axis which does not pass through the centre of the at least one body, or in embodiments where the marking defines more than one axis it may be desired for those axes not to pass through a single centre point. Thus the axes can be eccentric.
In addition, the vertical position of the meniscus within the body will of course be defined by the quantity of fluid within the body - more fluid will raise the vertical level of the meniscus, whereas less fluid will lower the vertical level of the meniscus, and the at least one marking may therefore be arranged as appropriate with respect to the location of the meniscus so as to define the at least one axis through the at least one body.
The invention will be further apparent from the following description which shows by way of example only embodiments of spirit level devices. Of the Figures: Figure 1 shows a front view of a body held vertically;
Figure 2 shows a section through Figure 1 along line A-A; Figure 3 shows a top view of a ruler;
Figure 4 shows a front view of a spirit level device positioned against a vertical surface and comprising two bodies of Figure 1 adhered to the ruler of Figure 3;
Figure 5 shows a side view of the spirit level device of Figure 4; and Figure 6 shows a front view of the markings of a further spirit level device.
As will be seen from the Figures, spirit level device 10 comprises two bodies 20, each body 20 comprising a circular front face 21 having a diameter of 20mm, a rear face 22 to which is adhesive 23 is applied, and a periphery wall 24 so as to define an inner volume 25 having a diameter of 18 mm and a depth of 1.5 mm and containing gas 26 and ethanol 27 coloured by a fluorescent dye, and defining a meniscus 28. Each body 20 has a total weight of 3 grams. The outer dimensions of each body 20 are a diameter of 20 mm and a thickness of 3.5 mm. A transparent plastic is used for front face 21, rear' face 22 and periphery 24. When body 20 is held generally vertically meniscus 28 will have a generally flat section between opposite sides of faces 21 and 22.
Bodies 20 are manufactured from two halves - a first chamber element and a second cap element. The chamber element provides a flat circular base with a vertically extending side wall terminating in a stepped section, and having a notch to simplify filling with fluid. The cap has a flat circular external shape and is shaped to mate with the stepped vertical side wall of the chamber element. The first and second parts are joined by ultrasonic welding, leaving the open notch into which a syringe is inserted and the fluid injected. Upon removal of the syringe, the notch is welded shut using ultrasonic welding.
Bodies 20 are mounted by adhesive 23 onto ruler 30 which comprises a 100 x 10 cm lightweight sheet of electret polypropylene (Permacharge Corporation, New Mexico,
USA) having a reversibly bound backing sheet 40. Ruler 30 is provided with surface printed markings 31 for measuring distance, together with markings 50 defining axes through bodies 20, the axes being at predefined angles to the longitudinal axis of the ruler 30. Markings 51, 52, 53 and 54 define axes at 45/225, 90/270, 135/315 and 180/0 degrees respectively to the longitudinal axis of ruler 30.
The component parts of the spirit level device 10 are simple and inexpensive to manufacture - bodies 20 are mass produced without the need to apply any surface markings or suchlike. Ruler 30 is produced using conventional printing processes, so as to be provided with metric ruler markings 31, markings 50 defining angles and axes relative to the longitudinal axis of the ruler 30, and other relevant messages, branding and advertising are also printed onto ruler 30.
To assemble the final ruler, adhesive is simply applied to the rear face of bodies 20, which are then placed centrally over markings 50 and adhered to ruler 30.
ha use, a folded spirit level device 10 is unfolded, backing sheet 40 removed, and spirit level 10 placed against a wall, to which it attaches by electrostatic force, hi order to ensure that spirit level 10 is horizontal, the user simply looks at bodies 20 to ensure that meniscus 28 is generally parallel with markings 54 and that ruler 30 is fully extended.
Similarly, in order to ensure that spirit level 10 is at 45 degrees to the horizontal, the user simply looks at bodies 20 to ensure that meniscus 28 is generally parallel with markings 51 and that ruler 30 is fully extended.
Once spirit level 10 is finished with, backing sheet 40 is re-applied and spirit level 10 folded up ready for future use. In order to maintain it and help ensure that it retains its ability to adhere to surfaces, the rear surface of ruler 30 (i.e. the face which in use contacts the surface to which it is attached) is simply wiped down with a dry tissue. When the electrostatic charge of the ruler 30 decreases, it can simply be re-charged by triboelectric charging (so called "tribocharging").
The spirit level 10 can be viewed as being a general purpose spirit level. However, in other embodiments (not shown) fewer markings 50 can be provided to ensure that spirit level 10 is only aligned by a user at a specified angle.
To effect the mounting on a wall (not shown) of a shelving unit (not shown) comprising a two metre long shelf and three vertical supporting spars, five spirit levels 10 are used. Two are arranged horizontally so as to define the full length of the shelf. They can be readily slid around on the wall whilst ensuring that they are horizontal and a user can step back from the wall in order to confirm that their location appears correct. Three spirit levels 10 can then be arranged vertically overlapping the two horizontal spirit levels 10 so as to define the locations of the vertical spars. Again, they can be readily slid around to ensure that their positioning is acceptable. Once a user is happy with the arrangement, markings can then be made on the wall. Alternatively, in embodiments of the invention in which the spirit level device 10 is provided with holes through which a drill can be passed, drilling through the holes can take place. Indeed, the spirit levels 10 can be provided with holes and markings for drilling and positioning relative to one another in order to allow drilling directly through the (holes of) spirit levels 10.
In a second embodiment (not shown), spirit level device 10 has ruler 30 provided with imperial/Whitworth markings to replace metric markings 30.
In a third embodiment (not shown), spirit level device 10 has ruler 30 provided with mixed metric and imperial/Whitworth markings to replace metric markings 30.
In a fourth embodiment (not shown), spirit level device 10 has ruler 30 provided with reverse (right to left) metric markings as well as forward (left to right) metric markings 30.
In a fifth embodiment (not shown), spirit level device 10 has ruler 30 provided with reverse (right to left) imperial/Whitworth markings as well as forward (left to right) imperial/Whitworth markings 30.
In a sixth embodiment (not shown), spirit level device 10 has ruler 30 provided with reverse (right to left) mixed metric and imperial/Whitworth markings as well as forward (left to right) mixed metric and imperial/Whitworth markings 30.
In a seventh embodiment (Figure 6), spirit level device 10 is provided with alignment markings in a number of forms - alignment markings 60 define an axis, and in-use the bottom of the meniscus 28 can be aligned so that it intersects the axis. However, alignment markings 61 are also provided, against which in-use the meniscus 28 can be conveniently aligned. By aligning meniscus 28 with markings 61, the spirit level device is aligned along the axis defines by alignment markings 60. In other embodiments, alignment markings 60 are not present.
It will be appreciated that it is not intended to limit the present invention to the above embodiments only, other forms being readily apparent to the skilled person without departing from the scope of the invention.