WO1990009254A1

WO1990009254A1 - Method and apparatus for cutting apertures

Info

Publication number: WO1990009254A1
Application number: PCT/GB1990/000258
Authority: WO
Inventors: Richard Ruben Ritchie; Eric Matthews; Robert James Maughan
Original assignee: Associated Western Limited
Priority date: 1989-02-16
Filing date: 1990-02-16
Publication date: 1990-08-23
Also published as: AU5155790A; GB2230733B; GB8903500D0; GB2230733A

Abstract

A method for cutting an aperture in a partition, such as a door or a wall, includes a first step of fixing a template (30) to a first face (A) of the partition and a second step of fixing a slotted guide plate (34) to the second face (B) of the partition. The desired outline of the aperture is marked around the outside of the template, which is then removed. It is then possible to cut through the partition from the first face to the second face around the marked desired outline, such that the slotted guide plate acts as a guide to ensure that the desired outline is followed. Also disclosed is an apparatus for putting the method in practice.

Description

METHOD AND APPARATUS FOR CUTTING APERTURES

The present invention relates to a method and apparatus allowing a user easily and accurately to cut an aperture, of a desired shape and size, in a partition. As used herein, the word "partition" means any space divider, such as a door, an internal wall or an external wall.

The method and apparatus of the present invention can be used to cut apertures of any shape for any purpose, although they are specifically intended to allow the cutting of rectangular apertures in doors to allow the insertion of a viewing and oral communications assembly of the type described in, for example. United States Patent No. 4,763,444. Of course, various methods of cutting apertures in doors are well known. Generally, a location on a vertical centre line of the door is chosen, a pilot hole is drilled, and the required aperture is then made using a hand saw, power saw or power router. However, such methods are generally very time consuming, and do not allow apertures to be cut accurately and consistently when the procedure is repeated. In general, the known methods are more effective when the door has been removed from its hinges, but even then it is difficult to ensure that the hole is cut accurately, and this of course means that the procedure takes longer than would otherwise be the case.

According to a first aspect of the present invention, there is provided a method for cutting an aperture in a partition, the method comprising the steps of: marking a desired position for the aperture on first and second faces of the partition; fixing to the first face of the partition, by reference to the desired position, a template having a size and shape corresponding to a desired size and shape of the aperture, and marking a desired outline of the aperture on the partition around the template; fixing to the second face of the partition, by reference to the desired position, a slotted guide plate, the position of the slot corresponding to the desired outline of the aperture; and cutting through the partition, from the first face to the second face thereof, around the marked desired outline. According to a second aspect of the present invention, there is provided a method in accordance with the first aspect of the invention comprising the steps of: marking a required centre location for the aperture; forming a hole through the partition at the centre location; fixing to the partition, by means of a screw through the hole at the centre location, a drill plate having at least two guide holes therein; forming positioning holes through the partition at locations corresponding to those of the guide holes; locating guide means in the positioning holes through the partition; fixing a template to a first face of the partition by means of the guide means, the template being of generally the required size and shape of the aperture which is to be cut, and having holes at the locations of the positioning holes, through which the guide means can pass; marking the first face of the partition around the template with the desired outline of the aperture; locating a guide plate, having a cutting guide slot, over the guide means on the second face of the partition; and cutting the aperture around the desired outline from the first face of the partition through to the second face thereof.

According to a third aspect of the present invention, there is provided apparatus for use in a method according to the second aspect of the invention, the apparatus comprising: a drill plate, having first and second guide holes therein; means for fixing the drill plate to the partition; guide means which, in use of the apparatus, can be passed through positioning holes in the partition formed at locations corresponding to the locations of the guide holes; a template of generally the desired size and shape of the aperture which is to be cut, and having holes at locations corresponding to the locations of the positioning holes; a guide plate, adapted to be fixed to the partition with a first side of the plate adjacent the partition, having a slot formed therein at a position corresponding to the desired position of the periphery of the aperture which is to be cut, and having holes at locations corresponding to the locations of the positioning holes, the slot having a widened portion at the first side of the plate and a narrower portion at the opposite side; and a saw having a blade which reciprocates between first and second end positions and which has a toothed region and a distal untoothed region, the length of the blade and of* the untoothed region being adapted to the thicknesses of the partition and of the guide plate such that, in use, in the first end position of tføe blade the toothed region can protrude through the partition into the widened portion of the slot in the guide plate but not into the narrower portion, while in both the first and second end positions of the b'lade the distal end of the blade can protrude through the widened portion into the narrower portion of the slot. Preferably, the method and apparatus are adapted for cutting an aperture into which there can be inserted a viewing assembly of the general sort disclosed in U.S. Patent No. 4,763,444.

For a better understanding of the present invention, and to show how it may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which Figures 1 to 10 illustrate successive stages in the method according to the first aspect of the present invention; and

Figure 11 is a cross-sectional view through a door in which an aperture is being cut. Figures 1 and 2 show a door 1 having an outside face A and an inside face B. The method is conveniently carried out with the door- wedged in an open position. A height gauge including a vertical element 2 and a T-bar 3 is used to mark the desired height relevant to the central point of the aperture. The length of the vertical element is set to the desired height, and a horizontal pencil mark 4 is made on the first face A of the door. Similarly, a horizontal pencil mark 5 is made at the required height on the second face B of the door. When the aperture is for the insertion of a viewing assembly, it should of course be cut at, or a little below, the eye level of a person of average height.

Then, as shown in Figure 3, the vertical centre line of the door is determined. A width gauge 6 has a vertical edge 7 and a horizontally extending member 8, which can be moved relative thereto. A scale 9 on the horizontally extending member is marked with various door widths, and the width of the door 1 may be lined up with the arrow 10 marked on the width gauge 6. The scale is designed such that, when this is done with the -5- vertical edge 7 of the width gauge against a vertical edge of the door 1 , the centre line of the door is indicated by the location of the hole 11. Thus, a pencil mark is made on the face A at the location of the hole 11 , with the upper surface of the horizontal member 8 being aligned with the mark 4 described with reference to Figure 1.

In Figure 4, the width gauge is seen aligned with the horizontal mark 5 made on face B of the door. Again, the location of the hole 11 indicates the position of the centre line of the door, but this time there is no need to make a mark at this position. Rather, a blade is used to score the surface of the door at the positions indicated in Figure 4 by the reference numerals 12, 13.

In Figure 5, there is shown the mark 14 made at the centre of the width of the door and at the required height, as described in Figure 3. A drill 15 is used to drill a hole through the door at the position of the mark 14. The scoring at positions 12, 13 on face B of the door ensures that if, for example, a veneer on the face of the door tends to crack when the drill bit penetrates through the door, this cracking does not extend beyond the score marks, and thus ensures that any cracking which occurs is limited to an area of the door which will eventually be removed when the required aperture is cut.

The next step in the method is illustrated in Figure 6. A master drill plate 16 is screwed to face A of the door using a centre wing screw 17 inserted in the hole 14, and locked tight when it is determined that it is square on the door. This is achieved using a plumb-bob 18 comprising a pivotable razor edge 19 and a fixed razor edge 20. When the razor edges 19 and 20 are aligned, it is determined that the master drill plate 16 is square. Holes are now drilled through the door at the locations indicated by the guide holes 21 , 22, and steel slip pins 23, 24 are inserted through these holes.

Pins 23, 24 now protrude through to face B of the door and, as shown in Figure 7 of the drawings, a template 25 having correspondingly located holes is placed over the pins. A blade is then used to score firmly along the edges of the template, for the reasons outlined above with reference to Figures 4 and 5 of the drawings. The template 25 can then be removed from the pins 23, 24.

Returning now to face A of the door, corner holes are drilled using guides 26, 27, 28, 29 as shown in Figure 8. Again the scoring on face B ensures that any veneer on the door does not crack outside the scoring. When this has been done, the master drilling plate 16 can be removed, with the slip pins 23, 24 left in place.

As shown in Figure 9 of the drawings, a marking template 30 is placed over the slip pins 23, 24 on face A of the door. The marking template 30 is of generally the same size and shape as the aperture which is required to be cut, but has indicator notches 31 , 32 in the upper regions of the side edges thereof. Alternatively, of course, the notches may be at any convenient location around the perimeter of the aperture. If the aperture is to be adapted for a viewing assembly of the sort disclosed in U.S. Patent No. 4,763,444, the template should be generally rectangular and of the required size. A pencil is then used to mark around the edge of the template 30, as indicated by reference numeral 33. The template can then be removed.

As shown in Figure 10 of the drawings, a saw-blade guide plate 34 is then placed over the slip pins 23, 24 and screwed firmly to face B of the door using the centre locking wing-screw 17. The saw-blade guide plate has a. recessed slot 35, 36 therethrough, the shape and position of this slot corresponding exactly to that of the reguired aperture, but being discontinuous at locations corresponding to those of notches 31 , 32 on the marking template 30.

Figure 11 is a schematic sectional view through ^• the door 1 while the aperture is being cut. The saw- blade guide plate 34 is screwed to the inside face B of the door by means of the screw 17. It can be seen that a saw blade 37 is being used to cut the aperture along the slot 35. For clarity, the blade is shown rotated through 90° from the cutting position, to allow the position of the teeth on the blade to be seen easily. The saw is provided with a stop plate (not shown) which can be used to ensure that it is kept a constant distance from the door. In use, the saw blade 37 reciprocates. To ensure that the aperture is cut fully, it is important that the teeth 38 of the blade pass all the way through the door 1. To allow thip to happen without causing the teeth to contact the metal of the blade guide plate, the slot 35,36 is widened by means of recesses 39,40 in the region adjacent the door. However, it is still necessary that the blade 37 pass through the narrow part of the slot 35,36, to ensure that accurate guiding is maintained, and to prevent the blade being forced backwards following contact between its end and a vertical surface of the plate. For this reason, the blade 37 is provided with an end region 41 which has no teeth. This may be ' achieved either by removing the teeth from a standard blade or by originally manufacturing a blade of the required shape. In practice, it has proved convenient to choose the length of the end region 41 such that, when the blade is extending fully forwardly through the door, as shown in Figure 11, two teeth protrude through the door. However, the length of the blade must be such that its end still remains in the narrow region of the slot 35, even when the blade is at the fully retracted end of its stroke. The aperture can now be cut from face A of the door using the specially adapted saw-blade. The saw blade can be moved along the line 33, which was drawn . on face A of the door as described with reference to Figure 9, and the slot 35, 36 ensures that the edges are cut accurately. The horizontal edges can be cut by moving the saw blade from one corner hole to the corresponding hole at the opposite end, and the vertical edges can be partially cut by running the saw blade from each corner hole to the respective marked notch. When this has been done, the saw-blade guide plate 34 and the slip pins 23, 24 can be removed, and the vertical cuts can be completed, to finish the cutting of the aperture and allow easy removal of the material which has been cut out. Thus, while the door has remained in position on its hinges throughout, the required position of the aperture has been accurately marked, and the saw has been accurately guided to ensure that an aperture of the required shape and size has been cut precisely and in a way which is easily repeatable. As will be appreciated, this procedure is also very much quicker than one in which the door has to be removed, and perhaps transported to a location where accurate cutting can be carried out. Although the invention has been described herein with reference to one specific example thereof, it will of course be appreciated that modifications and alternations falling within the scope of the amended claims also form part of the invention.

Claims

1. A method for cutting an aperture in a partition, the method comprising the steps of: marking a desired position for the aperture on first and second faces of the partition; fixing to the first face of the partition, by reference to the desired position, a template having a size and shape corresponding to a desired size and shape of the aperture, and marking a desired outline of the aperture on the partition around the template; fixing to the second face of the partition, by reference to the desired position, a slotted guide plate, the position of the slot corresponding to the desired outline of the aperture; and cutting through the partition, from the first face to the second face thereof, around the marked desired outline.

2. A method according to claim 1 comprising the steps of: marking a required centre location for the aperture; forming a hole through the partition at the centre location; fixing to the partition, by means of a screw through the hole at the centre location, a drill plate having at least two guide holes therein; forming positioning holes through the partition at locations corresponding to those of the guide holes; locating guide means in the positioning holes through the partition; fixing a template to a first face of the partition by means of the guide means, the template being of generally the required size and shape of the aperture which is to be cut, and having holes at the locations of the positioning holes, through which the guide means can pass; marking the first face of the partition around the template with the desired outline of the aperture; locating a guide plate, having a cutting guide slot, over the guide means on the second face of the partition; and cutting the aperture around the desired outline from the first face of the partition through to the second face thereof.

3. Apparatus for use in a method according to the second aspect of the invention, the apparatus comprising: a drill plate, having first and second guide holes therein; means for fixing the drill plate to the partition; guide means which, in use of the apparatus, can be passed through positioning holes in the partition formed at locations corresponding to the locations of the guide holes; a template of generally the desired size and shape of the aperture which is to be cut, and having holes at locations corresponding to the locations of the positioning holes; a guide plate, adapted to be fixed to the partition with a first side of the piate adjacent the partition, having a slot formed therein at a position corresponding to the desired position of the periphery of the aperture which is to be cut, and having holes at locations corresponding to the locations of the positioning holes, the slot having a widened portion at the first side of the plate and a narrower portion at the opposite side; and a saw having a blade which reciprocates between first and second end positions and which has a toothed region and a distal untoothed region, the length of the blade and of the untoothed region being adapted to the thicknesses of the partition and of the guide plate such that, in use, in the first end position of the blade the toothed region can protrude through the partition into the widened portion of the slot in the guide plate but not into the narrower portion, while in both the first and second end positions of the blade the distal end of the blade can protrude through the widened portion into the narrower portion of the slot..