GB2383138A

GB2383138A - Self-levelling projector for use with power tools

Info

Publication number: GB2383138A
Application number: GB0129882A
Authority: GB
Inventors: Daniel Bone
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2001-12-14
Filing date: 2001-12-14
Publication date: 2003-06-18
Anticipated expiration: 2021-12-14
Also published as: GB2383138B; GB0208845D0; GB0129882D0

Abstract

The device is for projecting an alignment guide (34,36) onto a workpiece, such as a wall to have holes drilled in. It comprises a mount (2) for mounting the device on or upon the wall, by fitting into a pre-drilled hole in the wall, and a self levelling projector such as laser (12) for projecting the alignment guide (34,36), which can be a beam or plane of red light, in a predetermined orientation relative to the vertical. Extra holes can then be drilled in a straight line with reference to the original hole using the alignment guide. The laser (12) is articulated to the mount (2) so that the alignment guide (34,36) emanates from that point on the workpiece where the mount (2) is situated and the device is oriented in a vertical position by means of ball race (8) which allows for free rotation between plastics disc (4) and retaining member (6). The gravitational force of battery (18) causes a pendulum action and results in the mounting bracket (16) coming to rest in a vertical axis. A gimbal mechanism (see Fig 6) can also be used as a self levelling mechanism to allow for the original mounting hole not being straight. The device may form part of a kit of parts which includes an electric drill (Fig 5, 28).

Description

PROJECTION DEVICE The present invention relates to a device for projecting an alignment guide onto a workpiece, the device comprising: a mount for mounting the device upon or within the workpiece, upon which workpiece the device is to project the alignment guide; a self-levelling projector for projecting the alignment guide onto the workpiece in a predetermined orientation relative to the vertical.

Devices of the above type are known for use in the building industry, for example. When a structure such as a wall for the side of a house needs to be constructed, it is important for the wall to be both vertically and horizontally aligned.

If the base row of bricks, for example, were laid at an angle to the horizontal, then the entire wall would be built with a horizontal slope. This could be disastrous to the long-term stability of both the wall and the building which it is intended to support.

The known alignment devices, which tend to employ laser optical emitters, can be laid upon the first brick (which is already known to be horizontally aligned) and project a horizontal beam therefrom. This horizontal beam is then used as a reference guide for the laying of the subsequent bricks in that row to ensure they are horizontal.

There are several problems associated with this known type of device, however. One of the greatest problems is that before the device can be accurately used the base position must itself be calibrated relative to a known reference point. In the above example, the first-laid brick must itself be horizontal for the subsequent reference guide to also be horizontal.

Alternatively, even if there is no requirement to first calibrate a device relative to the horizontal, the location of the device itself may be an issue. For example, it

may be undesirable to site the device close to the position where work needs to be done as the device may interfere with this work.

It has been found that it would be useful for the point of emanation of the alignment device to be situated at the same spot as the mount is positioned upon the workpiece, or at least along the same plane of reference thereas.

Accordingly the present invention provides, in one aspect, a device of the known type characterised in that the projector is articulated to the mount so that the alignment guide emanates from that point on the workpiece where the mount is situated. This provides significant advantage over known such devices because if a first reference point is made in a workpiece, then the mount may be affixed thereto and then the alignment guide is automatically aligned with this mount point. Hence no separate calibration or alignment is necessary.

Preferably the projector self-levels under the influence of gravity. This means that no external force is needed in order for the projector to find its level. The projector may act like a pendulum in order to self level and the action of the pendulum may be damped in order to prevent excess oscillation.

The projector is preferably articulated to the mount and more preferably freely rotatable thereabout. In a preferred embodiment the projector is articulated to the mount via a ball race bearing assembly.

Advantageously the projector may include a laser emitter. Furthermore the alignment guide may comprise a visible line, lines cross wires or even a grid.

In the preferred embodiment the alignment guide provides a reference point on the workpiece which is horizontally or vertically aligned with that position on the workpiece where the mount is situated. Preferably the mount may comprise a generally cylindrical projection which is resiliently radially expandable or

contractable in order to allow the mount to centre itself in the respective hole, cut or rebate.

According to a further aspect of the present invention there is provided a kit of parts for enabling a plurality of aligned holes, cuts or rebates to be formed within a workpiece, the kit of parts comprising; i) a power tool for forming an initial hole cut or rebate in the workpeice, and; ii) a device for projecting an alignment guide, the device including a mount to fit within the hole, cut or rebate formed by the power tool, the device further comprising a self-levelling projector for projecting the alignment guide onto the workpiece in a predetermined orientation relative to the vertical. and wherein the projecting device is articulated to the mount so that the alignment guide emanates from that point on the workpiece where the mount is situated.

Such a kit of parts provides the facility for the projecting device being detachable from the tool so that a hole, cut or rebate may be formed in the workpiece, the projection device placed in such hole, cut or rebate and then the tool following the alignment guide to form the next hole, cut or rebate in a defined position based upon this alignment guide.

Preferably the projecting device is removably retained on or contained within the power tool. This means that the chances of it being lost by being misplaced are reduced.

According to yet a further aspect of the present invention there is provided a method for projecting a self-levelling alignment guide onto a workpiece, the method comprising the steps of : a) forming hole, cut or rebate within a workpiece, or attaching a projection thereto;

b) fitting a mount within the cut, hole or rebate, or attaching the mount to the projection, which mount is articulated to a self-levelling projector; c) projecting, from the self-levelling projector, an alignment guide onto the workpiece; which alignment guide is projected onto the workpiece in a predetermined orientation relative to the vertical.

An embodiment of the present invention will now be described by way of example only, and with reference to the accompanying drawings of which Figure I shows a side view of a device in accordance with the present invention; Figure 2 shows an end view from the right hand side of that of Figure 1 ; Figure 3 shows a plan view of a workpiece to which the device in accordance with the present invention is mounted and hangs vertically downwards; Figure 4 shows a schematic view along the line X-X of Figure 2; Figure 5 shows a schematic illustration of a power tool including a device according to the present invention, and: Figure 6 shows a perspective view of an alternative embodiment of the present invention.

Referring firstly to Figures 1 and 2, it can be seen that the device in accordance with the present invention comprises a mount (2) which, in this example, is chosen to be able to fit into a hole drilled by a drill bit or the like. Of course, instead of the mount (2) being a cylindrical projection as shown in the figures, it is possible for this mount to take any suitable shape or configuration so that it may fit into the appropriately shaped hole, cut, rebate, channel etc. formed in a workpiece to which the device is to be mounted.

Coupled to the mount (2) is a circular disc (4) which is itself formed within a plastics retaining member (6) via a ball race mechanism (8). The ball bearings of the ball race (8) cannot be seen from Figures 1 and 2 but they are visible in the Figure 4 cross section.

The plastics disc (4) is coupled to the mount (2) and is rotatably fixed thereto.

Because the retaining member (6) is coupled to the plastics disc (4) via the ball race (8) then the plastics disc (4) may freely rotate within the retaining member (6) via the ball race (8).

Rigidly coupled to the retaining member (6) via mounting pins (10) is a projector, in this example laser emitter (12). The laser (12) is rigidly coupled via a couple (14) to mounting bracket (16). At its lower end the mounting bracket (16) supports (in this case is integrally formed therewith) a battery (18). The positive (20) and negative (22) terminals of the battery are shown in the Figures because they supply power from the battery (18) to the laser (12).

Because the laser (12) is rigidly coupled to the mounting bracket (16) via the couple (14) and also because the mounting bracket (16) is rigidly coupled to the retaining member (6) via the mounting pins (10), then it can be seen that the laser (12) may freely rotate about the mount (2) by virtue of the ball race (8). However, because the mounting bracket (16) is weighted by battery (18) the mass of which is deliberately greater than the mass of the remainder of the mounting bracket (16) then the mounting bracket (16) acts as a pendulum under the influence of gravity so that it will come to rest at its lowest point and therefore ensure that this rest"position"is constant under the force of gravity. By aligning the laser (12) in a known relationship relative to the mounting bracket (16) then the attitude of the laser (12) to the horizontal will be known at any stage where the battery (18) comes to rest under the action of gravity following its pendulum oscillation where allowed to move freely and the device is held in a stable position via the mount (2). Referring now also to Figures 3 and 4 it is shown how the device operates in use. A workpiece (24), in this example a horizontal wall, has a plurality of holes (26) drilled therein via a conventional drill such as drill (28) shown in Figure 5.

In Figure 3 the device is mounted in one such hole (26) although this cannot be seen from the Figure because the device obscures the hole (26).

In the example shown the mount (2) is chosen to be a cylindrical projection and is formed from resilient plastics material which has a plurality of longitudinally extending slits (30) formed therein, so that in its rest position the external periphery of the mount (2) forms an oval shape such that the diameter thereof in a central region where the slits (30) exist is greater than at the extremes thereof. In this way once the mount (2) is forced into a suitably dimensioned hole (26) then the resilience of the mount (2) achieved by the slits (30) allows the mount to contract slightly within the hole (26) and thereby form a tight fit therein. Of course it will be appreciated that any form of resilient character will be efficacious for the mount (2) to operate. For example, the mount (2) may be formed from an expandable foam-type material which is initially compressed in order to be able to fit within the hole (26) and then expands within the hole in order to take up a central position located therein. Alternatively the mount may be, for example, an inflatable balloon-type structure which is inserted into the hole and is then pumped with air to expand to fit centrally within the hole. Any form of variant such as that listed above will be adequate to work within the scope of this invention.

The mount (2) is, therefore, semi-rigidly mounted within its respective hole (26). As can be seen from Figure 4 the ball race (8) includes a plurality of ball bearings (32) which, in this example at least, allow for free rotation between the plastics disc (4) and retaining member (6). This effectively, means that there is free rotation between the mount (2) and the mounting brackets (16) and hence the laser (12).

Thus, once the mount has been placed into its respective hole (26) and allowed to be free of any other external forces, the pendulum action due to gravitational force acting upon the relatively heavy battery (18) compared to the remainder of the mounting bracket (16) means that the mounting bracket (16) will perform a to and fro oscillating motion whose amplitude is ever decreasing until it comes to a rest in a vertical position. Of course, it is feasible for the device to be damped to quickly bring the oscillations to a minimum and this may be achieved in numerous ways, the most

effective one of which being increasing the size of the ball bearings (32) within the ball race (8) so that an under-damped system is not possible to be achieved.

Referring particularly to Figure 3 it can be seen that the device is in a vertical plane as shown by the line Y-Y and that the laser (12) has been chosen to emit its alignment guide along both the vertical plane Y-Y and also the horizontal plane Z-Z.

In the present example the alignment guide which emanates from the laser (12) has been chosen to be visible and comprises a first, in this case horizontal, beam of light (34) and a second, in this case vertical, beam of light (36). It will, of course, be apparent to those skilled in the art that any suitable alignment guide may be projected by the laser (12), the only important feature to note here that the entire device takes its reference point from the vertical Y-Y but from this point any suitable alignment guide may be emitted. Whilst in the above example a beam of light has been chosen to emanate from the laser (12) it is equally efficacious with the present invention for a plane of light to emanate. Thus, for example, when the laser (12) is emitting a plane of light on a workpiece which happens to be a wall which is curved, the plane may be visible from different parts of the curved wall. Such would not be the case, for example, if the wall were perfectly straight, because a beam of light would not be able to cover projections mounted on the wall. Thus there are certain instances in which a plane of light is by far the best type of alignment guide to emanate from the laser (12).

In the present circumstances where the invention is readily envisaged to be used with power tools, it is more usual that the alignment guide (34,36) will actually comprise a simple horizontal line (in this case 34) and most probably will comprise a visible beam of laser light whose wavelength provides for a red light which is clearly visible by a user.

Instead of a simple horizontal line (34) being emitted or indeed a simple vertical line (36) being emitted by the laser (12) cross wires or other lines or grids etc.

are equally possible. Of course the complexity of the laser used mainly to be altered from a simple laser as shown in the drawings, but this is simply a matter of choice.

In the example shown, if the user is, for example, wishing to drill a further hole (26) aligned with that particular hole in which the device is mounted as shown in Figure 3, and the further hole needs to be horizontally aligned therewith, it is simply a matter of marking a position on the workpiece (24) along the line (34) and then drilling a further hole at this particular point.

Reference now also to Figure 5 shows a kit of parts suitable for use with the present invention which comprises, a power tool, in this case an electric drill (28) of conventional design with a chuck (38) for mounting a drill bit (40) therewithin.

Power is supplied via mains power cable (42) to the drill which is actuated by means of Figure 44. All this is conventional in the art.

It can be seen that the alignment device shown generally as (46) in Figure 5 is coupled to the body of the drill (28) via a flexible cord (48). It is possible for the flexible cord (48) to be withdrawn a considerable distance from the drill (28) and the spring-loaded so that it returns within the body of the drill (28) so that the device (46) somehow locks either to the outside or the inside of the drill (28). The method by which this is achieved is not germane to the present invention so will not be described any more herein.

By reference now to Figure 6 an alternative embodiment of the present invention will be described. In this figure 6, similar components to those of figures 1-5 bear corresponding reference numerals.

It can be seen from figure 6 that the mount (2) is coupled to a retaining member 6a via a central plastics disc (4) and ball race (8) as in the embodiment shown in figures 1-5. Although the geometry of the embodiment of Figure 6 is different to that of figures 1-5 the function of the above components is identical.

The retaining member (6aO is cylindrical and the ball race (8) is formed around the central plastics disc (4) so that the outer portion (6a) of the retaining member may freely rotate about the central plastics disc (4) and about the axis A-A.

This is in common with the embodiments of figures 1-5.

Two pivot points (50a) and (50b) are diametrically opposed to one another about the peripheral circumference of the retaining member (6a). The pivot points (50a) and/or (50b) may be simple indentations in the surface of the retaining member (6a), or they could be further ball races. The purpose, in either case, though, is to enable the retaining member (6a) to be articulated to a supporting yoke (52).

The supporting yoke (52) has two extending arms (54a) and (54b) each of which terminates at a support member (56a) and (56b) respectively. Protruding from each support member (56a, 56b) and extending along an axis B-B inwardly toward the retaining member (6a), are respective mounting arms (58a, 58b). The ends of the arms (58a, 58b) remote from their respective support members (56a, 56b) are in operative engagement with the pivot points (50a, 50b). This enables free rotation of the retaining member 6a about the axis B-B.

It will be appreciated that as the retaining member (6a) is free to rotate independently about two orthogonal axes A-A and B-B, the structure shown in Figure 6 acts as a gimbal. Thus, under the influence of the lower weight in the form of the battery (18), the gimbal structure of Figure 6 will always settle under the influence of gravity such that the axis B-B is horizontal. This will broadly be the case whatever the attitude or angle of the axis A-A to the horizontal, but not including extreme angles at which the frictional forces on the bearings can resist the forces of gravity.

The above gimbal structure can have advantage if the user drills, for example, a first hole (26) in a vertical workpiece and this hole does not extend parallel to the horizontal. The gimbal structure enables the device to still function and be able to pivot freely about a horizontal axis to the free pivoting of the retaining member (6a)

about the axis B-B. This, in effect, compensates for the axis A-A not being horizontal. If the axis A-A of the mount (2) were not horizontal in the embodiments of Figures 1-5, then this might hinder the free pendulum action of the device. This shortcoming is alleviated with the embodiment of Figure 6.

It will be appreciated that the device illustrated in Figure 6 could function if only one mounting arm (58a) or (58b) were used to couple the yoke (52) to the retaining member (6a).

A particular advantage is associated with having a device (46) detachably secured to a drill (28) in this manner. For example, it is possible for a user to drill into a workpiece using a drill bit (40) and then apply the device (46) to the hole so drilled whilst allowing for the flexible cord (48) to be extended so that the drill can be used to drill the subsequent hole whilst the device (46) is in place in the first hole.

In the above example a power tool (28) has been chosen to be a drill which drills holes via drill bit (40). Of course, any suitable power tool will do such as an angle grinder, jig saw, circular saw etc. etc. In fact the only requirement is that the power tool be able to cut, gouge, slice or drill some form of hole rebate recess channel etc. into a workpiece which can then be used as a position from which to mount the alignment device.

In the above it has been stated that the alignment guide (34,36) emanates from that point (26) on the workpiece where the mount (2) is situated. It will be understood by those skilled in the art that"that point"not only refers to the physical location of the mount (2) in the workpiece, but the axis along which the mount (2) is brought into contact with the workpiece Thus, for example, it is possible for the mount (2) to be situated within hole (26) in the workpiece, but the laser (12) (while still articulated to the mount 2 via the mounting bracket (16) ) is axially displaced therefrom along the axis defined by the line in which the mount (2) is brought into the hole (26). In other words it is possible for the laser (12) to be displaced from the surface of the workpiece but still allow the invention to work equally well.

Claims

1. A device for projecting an alignment guide onto a workpiece, the device comprising : a mount for mounting the device upon or within the workpiece, upon which workpiece the device is to project the alignment guide; a self-levelling projector for projecting the alignment guide onto the workpiece in a predetermined orientation relative to the vertical; the device characterised in that the projector is articulated to the mount so that the alignment guide emanates from that point on the workpiece where the mount is situated.

2. A device according to Claim 1 wherein the projector self-levels under the influence of gravity.

3. A device according to either Claim 1 or Claim 2 wherein the projector acts like a pendulum in order to self-level.

4. A device according to Claim 3 wherein the pendulum action is damped to prevent excess oscillation.

5. A device according to any one of the preceding claims wherein the projector is articulated to the mount.

6. A device according to Claim 5 wherein the projector is freely rotatable about the mount.

7. A device according to either Claim 5 or Claim 6 wherein the projector is articulated to the mount via a ball race.

8. A device according to any one of the preceding claims wherein the projector includes a laser emitter.

9. A device according to any one of the preceding claims wherein the alignment guide comprises a visible line, lines, crosswires, grid or plane or planes.

10. A device according to any one of the preceding claims wherein the alignment guide provides a reference point on the workpiece which is horizontally or vertically aligned with that position on the workpiece where the mount is situated.

11. A device according to any one of the preceding claims wherein the mount comprises a generally cylindrical projection which is resiliently radially expandable or compressible

12. A device according to any one of the preceding claims wherein the device is freely rotatable within two orthogonal planes.

13. A device according to any one of the preceding claims wherein the selflevelling projector is coupled to a gimbal mechanism.

14. A kit of parts for enabling a plurality of aligned holes, cuts or rebates to be formed within a workpiece, the kit of parts comprising; i) a power tool for forming an initial hole, cut or rebate in the workpiece, and; ii) a device for projecting an alignment guide, the device including a mount to fit within the hole, cut or rebate formed by the power tool, the device further comprising a self-levelling projector for projecting the alignment guide, onto the workpiece in a predetermined orientation relative to the vertical, and wherein the projecting device is articulated to the mount so that the alignment guide emanates from that point on the workpiece where the mount is situated.

15. A kit of parts according to Claim 14 wherein the projecting device is removably retained on or contained within the power tool.

16. A method for projecting a self-levelling alignment guide onto a workpiece, the method comprising the steps of : a) forming a hole, cut or rebate within a workpiece, or attaching a projection thereto; b) fitting a mount within the cut, hole or rebate, or attaching the mount to the projection, which mount is articulated to a self-levelling projector; c) projecting, from the self-levelling projector, an alignment guide onto the workpiece, which alignment guide is projected onto the workpiece in a predetermined orientation relative to the vertical.