GB1581097A

GB1581097A - Glass cutting tool

Info

Publication number: GB1581097A
Application number: GB6614/78A
Authority: GB
Original assignee: HOECKENREINER A
Current assignee: HOECKENREINER A
Priority date: 1977-02-21
Filing date: 1978-02-20
Publication date: 1980-12-10
Also published as: JPS606291B2; NL7801944A; SE7801955L; AT368109B; FR2380995A1; ATA115678A; JPS53124391A

Description

(54) GLASS CUTTING TOOL (71) I, AUGUST HOCKENREINER, of Gräfstrasse 66, 8000 München 60, Germany, of German Nationality, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a glass cutting tool especially suitable for cutting out elliptical or circular glass plates.

Different types of tool for cutting out elliptical or circular glass plates are known.

All of these are based on a known instrument for drawing ellipses. The tools known to date are normally equipped with a table with a laterally arranged pillar. The actual glass cutting tool is suspended above the table from this pillar (cf. e.g. German Patent No: 432,182).

A considerable disadvantage of these conventional glass cutting tools lies in the fact that the size of the ellipses or circles which can be cut out is limited by the presence of the pillar located at the side, and from which the actual glass cutting tool is suspended.

The present invention provides a glass cutting tool for cutting out elliptical or circular glass plates, which is simple in design and makes it possible to cut out large discs having diameters up to several meters.

Accordingly, therefore, the present invention comprises a glass cutting tool including a base plate having on one side means for releasable attachment to the glass to be cut and two guide rails arranged at right angles to each other and in the same plane located on the other side thereof, at least one guide rail including a slide member slidably mounted thereon for movement along said rail, a guide means pivotally attached to the slide member and a straight edge located by said guide means and carrying a glass cutter on its underside.

The tool according to the invention is preferably secured directly to the glass plate to be cut by suction its operation is thus not being hindered by any structural member located on the cutting side.

The suction cups, preferably four-one at each corner of the base plate-may be simple suction cups, though suction cups of a known design, which can be made to adhere by the action of a lever, are preferred.

The guide rails are preferably of a dovetailed or similar shape to ensure that the slides are firmly lodged in the guide rails and can only be moved backwards and forwards along the respective guide rails.

The cutter provided at one end of the straight edge will be of the usual diamond or steel wheel type.

When it is required to cut out circular glass plates, only one slide is used which is fixed in position along either one of the guide rails, preferably at their point of intersection, for instance by means of a setscrew. The setscrew is preferably screwed into a threaded hole provided at the point of intersection of the axes of the guide rails from below.

Preferably, a knob is provided on the top side of the straight edge, juxtaposed to the glass cutter, with the help of which the said glass cutter can be guided along the desired path.

In a preferred embodiment suitable for cutting out elliptical glass plates, a scale is provided on the upper side of the straight edge which starts at the glass cutter, windows being provided in the guides for the straight edge for the purpose of viewing the scale.

The straight edge may be held in the guides sufficiently firmly that it can be moved along the said guides only by exerting a considerable force, but preferably the straight edge will be fixed in position in the guides by means of a setscrew. Making use of the scale, the ellipse to be cut out by means of the glass cutter can be defined unequivocally, because the distance from the glass cutter to the midpoint of the first guide corresponds to the short half-axis of the ellipse to be described, whilst the distance from the glass cutter to the mid-point of the second guide corresponds to the long half-axis of the said ellipse.

Since the angle between the central axis of the ruler and the tangent to the ellipse, at the point of intersection between the said central axis of the straight edge and the ellipse, changes continuously during cutting, and is equal to 90" at the point of intersection between the ellipse and the axes of the ellipse, the glass cutter is not, in general, moved in a completely rectilinear fashion but always undergoes some lateral displacement. In the case of ellipses which approach fairly closely to a circle, this effect can be neglected. In order to be able to cut out cleanly ellipses having greatly varying axial ratios, the glass cutter is preferably rotatably mounted on a follower attached to the straight edge so that it can be moved in the correct direction throughout.

Using a glass cutting tool of the type described above, it is not possible to cut out ellipses in which the axial ratio exceeds a certain value because the glass cutter which is located at the end of the straight edge would otherwise come into contact with the guide rail which corresponds to the short axis of the ellipse. This guide rail cannot, however, be shortened to any desired extent since the slide which runs along the guide rail corresponding to the short axis of the ellipse would otherwise be pushed beyond the other end of tÇ said guide rail.

A preferred embodiment of the glass cutting tool according to the invention is, therefore, provided at one end of the guide rail, corresponding to the short axis of the ellipse to be cut out, with a detachable rail extension piece which can be attached to the opposite end of the same guide rail.

The guide rail extension piece may be secured to the ends of the guide rail by various known means. These include in particular coupling means of all kinds.

In a preferred embodiment this coupling means is provided by using a guide rail extension piece with a lower recess at the end facing the guide rail, and providing the guide rail with upper recesses corresponding to the said lower recess, at both sides of the rail, at least one dowel hole being provided in the extension piece at the region of the recess and at least one corresponding dowel being present at the two ends of the guide rail. It will be obvious that such a dowel must be arranged laterally with respect to the guide groove of the guide rail so as not to interfere with the movement of the slide. One guide hole and one dowel are preferably provided at each side of the guide groove.

Two embodiments of the invention will now be explained in more detail by means of the appended drawings.

In the drawings: Figure 1 is a plan view of one embodiment of a tool according to the invention.

Figure 2 is a front view of one of the guide rails.

Figure 3 is a detailed view of the follower.

Figure 4 is a plan view of a tool with guide rail extension peice, and Figure 5 shows a pin and socket attachment between guide rail and guide rail extension piece for the embodiment according to Figure 4.

The tool comprises a base plate 1 provided on its underside with four suction cups 2 which can be actuated by pressure exerted by a lever (not shown). A carrier plate 24 is screwed to the base plate 1 by means of two knurled-head screws 25. The carrier plate 24 has on its upper surface two guide rails 3 and 4 arranged at right angles to each other and crossing at the same level. Their cross section is shown in Figure 2. Slides 5 and 6 are arranged in the guide rails. U-shaped guides 7 and 8 are attached to the slides 5 and 6 by means of pivots and a straight edge 9 passes through the guides.

A rotatably mounted follower 10 is provided at one end of the straight edge 9 and a glass cutter 17, shown in Figure 3, is secured to the follower 10. Above the glass cutter there is a holding knob 11. The straight edge 9 is provided with a scale 12. The straight edge can be fixed in position in the guides 7 and 8 by means of the setscrews 15 and 16.

Since the guide rails 3 and 4 are not attached directly to the base plate 1 but vif a carrier plate 24, they can be replaced in a simple manner (together with the carrier plate 24) by larger or smaller guide rails, so as to adapt the cutting tool to the size of the glass plates to be cut out.

A threaded hole 23 is provided at the point of intersection of the axes of the guide rails 3 anc 4, and a setscrew is screwed into this from below. This can be used to fix one of the slides 5 and 6 in position when the tool is to be used to cut out circular plates.

In the second embodiment illustrated in Figure 4 and Figure 5 a guide rail extension piece 18 is provided at one end of the guide rail 4, which is secured to the guide rail 4 by means of a known securing means illustrated in detail in Figure 5. The said guide rail dxtension piece can be removed and secured to the opposite end. For this purpose the guide rail 4 is provided (at both ends) with recesses 19 from which two dowels 20 protrude upwards. The said dowels 20 are located on both sides of the guide groove. The extension piece 18 is provided with an appropriate recess 21 and two corresponding guide holes 22.

When this embodiment of a glass cutting tool is used to cut out a very flat ellipse, the extension piece 18 is secured to one end of the guide rail 4. Cutting is then started at any arbitrary point. Cutting is interrupted before the glass cutter comes into contact with the extension piece 18 or the slide is pushed beyond the other end of the guide rail 4, the extension piece 18 is removed and secured to the opposite end of the guide rail 4. Cutting can then be continued until the ellipse has been completed.

Claims

WHAT I CLAIM IS:-

1. A glass cutting tool comprising a base plate having, on one side, means for releaseable attachment to the glass to be cut and two guide rails arranged at right angles to each other and in the same plane located on the other side thereof, at least one guide rail including a slide member slidably mounted thereon for movement along said rail, a guide means pivotally attached to the said slide member and a straight edge located by said guide means and carrying a glass cutter on its underside.

2. A tool according to Claim 1 wherein the means for releasable attachment to the glass to be cut are suction cups.

3. A tool according to any one of claims 1 or 2 wherein the guide rails are mounted on a carrier plate which is secured to the base plate.

4. A tool according to any one of claims 1, 2 or 3 wherein a knob is provided on the upper side of the straight edge juxtaposed to the glass cutter.

5. A tool according to any one of claims 1 to 4 wherein a scale is provided on the upper side of the straight edge, which scale starts at the glass cutter, windows for viewing the said scale being provided in the guide means.

6. A tool according to any one of the preceding claims wherein the guide means are U-shaped and the straight edge is located therein by setscrews.

7. A tool according to any one of the preceding claims wherein the glass cutter is secured to the straight edge through a rotatably mounted follower.

8. A tool for cutting out circular pieces of glass and according to any one of the preceding claims wherein one guide rail only includes a slide member, which slide member is fixed in position at the point of intersection of the guide rails by a setscrew received by a screw-threaded hole in the guide rails at that point.

9. A tool for cutting out elliptical pieces of glass and according to any one of claims 1 to 7 wherein both guide rails include slide members and guide means pivotally attached thereto, the straight edge being located by each said guide means.

10. A tool according to claim 9 wherein there is provided a detachable guide rail extension piece secured to one end of the guide rail corresponding to the short axis of the ellipse to be cut out, said guide rail extension being capable of being secured to the opposite end of the said guide rail.

11. A tool according to claim 10 wherein the extension piece is provided with a lower recess at the end facing the guide rail and the said guide rail has appropriate upper recesses at both at both ends, at least one dowel being provided in the guide rail or guide rail extension piece in the region of the recess, and at least one corresponding dowel being provided in the recess in the guide rail extension piece or the guide rail and arranged laterally with respect to the guide groove of the guide rail.

12. A glass cutting tool substantially as herein described with reference to Figures 1, 2 and 3 of the drawings.

13. A glass cutting tool substantially as herein described with reference to Figures 4 and 5 of the drawings.