Method and Drilling Template for Establishing Mounting Holes for Frameless Spectacles
Background of the invention The present invention concerns a method for establishing mounting holes in spectacle glasses for frameless spectacles by using a drilling jig including a preferred number of through-going drilling holes that are disposed in relation to the datum line of the spectacle glass and are held at the front side of the spectacle glass at a desired position for guiding the drill used during drilling the holes. The invention also concerns a jig equipment for performing the method.
The method hitherto used in connection with establishing mounting holes in glasses for frameless spectacles is that the above templates exist for the purpose, including a flap with a line marking that is placed in relation to an actual spectacle glass shape and datum line at the front side of the glass for establishing holes for fastening the nose bridge and side bars for the frameless spectacles.
The method is that at the front side of the glass, a tape piece is established on which the datum line for the actual glass is drawn up. The template is positioned in relation to the datum line and is maintained manually during the drilling of the holes in the glass with a drill. The said work with establishing mounting holes in the glasses in com ection with the making of frameless spectacles is an even very time-consuming precision work, the result of which unfortunately sometimes appears to be useless as a consequence of difficulty with holding the template at the correct position during drill- ing of the mounting holes. If it is thus assumed that the making of a pair of frameless spectacles takes about 1.5 hour, it is to be expected that establishing the mounting holes constitutes about 60 minutes of the total time for making the spectacles, and in that connection is to be mentioned that the time for making also includes grinding the glasses and mounting of nose bridge and side bars, respectively. Wrongly placed holes will, due to the special construction of the frameless spectacles, be revealed immediately, as errors of 0.25 mm can be seen by an experienced user of spectacles. The said spectacle glasses may, as a consequence of a certain percentage of error at the making of the mounting holes, be discarded, with the consequent loss for the optician doing
the work with making the frameless spectacles.
In Fig. 1 is shown an often used, prior art tool for making mounting holes in glasses for frameless spectacles. The tool is constituted by a perforated template 6 which is shows from different angles of viewing in Fig. 1. A drill 14, a countersinking drill 36, as they are drilling holes in the spectacle glass, assembling pins 38 as assembling means between nose bridge and side bars and glasses, respectively, assembly pincers 40 for locking the pins 38 and a dismounting tool for dismounting pins and thereby nose bridge and side bars 42. It is to be noted that glasses for frameless spectacles and for that sake other glasses for other types of spectacles are formed by means of a template that defines the shape of the actual spectacle glass and includes a set of holes for placing the datum line in the glass. An example of such known template 43 for use in formation of spectacle glasses is shown in Fig. 3. In Fig. 2 is further shown a prior art template 16 for use in controlling the formed shape of a spectacle glass.
However, from FR 2 803 669 is known a drilling jig for establishing holes for side bars and nose bridge in frameless spectacles. The jig includes a holder for fastening a spectacle glass jig with a glass inserted therein, the shape of which corresponding to the shape of the jig. The spectacle glass is supported at the underside of a retainer which is clamped by threaded rods that are passed through holes in the jig. A drilling jig is used a bevelled block with drilling holes for guiding a drill for drilling mounting holes in the spectacle glass. The bevelled block is supported at the side of the spectacle glass jig side and is fastened to it so that the bevelling is in contact with the upper side of the spectacle glass jig, whereby there may be compensated to some degree for the curvature of the spectacle glass. The drilling jig is thus particularly suitable in cases where the holes for fastening nose bridge and side bars are established in the area around the datum line of the spectacle glass, where the bevelling on the drilling jig will provided an approximately correct compensation for the curvature of the glass. In that connection it is important to understand that the said holes for fastening nose bridge and side bars are to be oriented perpendicularly to the surface of the glass in order to attain the correct angle between the glass and the rest of the frameless spectacle.
As the frameless jig equipment known from FR 2 803 669 presupposes that the drilling jig is supported at the upper side of the spectacle glass template there will not, except if the holes are to be established in the datum line of the glass, be possibility of compensation for the curvature of the glass. This means that hole drilled by using the said prior art drilling jig equipment according to FR 2 803 669, which is disposed outside the datum line for the actual spectacle glass, will not be oriented correctly, and therefore it may be assumed that this drilling jig equipment will not be usable for drilling holes for nose bridge and side bars in cases where the said holes are established outside the datum line. However, one may operate with performing adaptation of the bevelling of the drilling jigs so that these provide for the curvature of the spectacle glass; this will, however, require making of a not insignificant number of drilling jigs for the drilling jig equipment, depending on the curvature of the actual spectacle glass, which has to be regarded as being unrealistically expensive.
In the light of the many error possibilities that are present with the known tool/template equipment used for establishing mounting holes in spectacle glasses for frameless spectacles and the considerable time consumed for establishing the said mounting holes and lastly, but not the least, the costs connected with the discarding of spectacle glasses with inaccurately disposed mounting holes, it has been found suit- able to seek alternative solutions for performing a rapid and very precise establishing of the said mounting holes in spectacle glasses for frameless glasses.
By the invention it has thus been realised that utilising the already known control templates for checking whether the shape of a spectacle glass is correct in relation to the template can be utilised for this purpose, as the spectacle glass is placed in a template corresponding to the shape of the glass with a first cutout so that the periphery of the glass is in contact with the edge of the first cutout, the periphery of the first cutout being in contact with the side edge of the first cutout, placing the drilling jig in a second and a third cutout in the periphery of the first cutout for guiding accommodation and securing of the end of the drilling jig facing away from the cutout so that its drilling jig holes are disposed and fixed in a preferred position relative to the datum line of the spectacle glass and in contact with the spectacle glass, after which drilling of the mounting holes in the spectacle glass is performed.
By this method is eliminated a number of the human errors that may arise in connection with establishing the mounting holes in the spectacle glasses for frameless spectacles, simply because the jig is no longer held in parallel with the datum line manually, but is held controlled at a position in the second and tliird cutout and, in addition, in contact with the surface of the spectacle glass, whereby the person making the spectacles may entirely concentrate on drilling the mounting holes correctly. Essential sources of error are thus eliminated in connection with establishing the said mounting holes, meaning a considerable reduction in the time used for establishing the said mounting holes.
By using the method according to the invention, a set of frameless spectacles may thus be made in about 1/3 of the time presently used for making these spectacles, since establishing the mounting holes may be performed without required drawing up of the datum line for the actual spectacle glass and without performing a manual develop- ment of the jig relative to the datum line. It will thus be possible to make the said frameless spectacles at a lower cost.
A jig equipment for performing the method according to the invention uses a template known per se, including at least one first cutout, the outline of which corresponding to the shape of an actual spectacle glass that may be placed in the cutout in the template with the rim of the spectacle glass in contact with the sides of the said first cutout in the template. Such a jig equipment is characterised in that at relevant positions in relation to the position of the datum line for the actual spectacle glass at the sides of the jig and preferably in connection with the said first cutout for the spectacle glass, at least one further cutout is provided for guiding accommodation and securing of the end of a drilling jig facing away from the cutout, so that the drilling holes in the drilling jig are disposed and secured in a preferred position relative to the datum line of the spectacle glass.
Hereby is achieved the advantage that the jig, as previously mentioned, is secured at a position in relation to the datum line for the spectacle glass concerned. In connection with establishing the mounting holes in the glasses, two types of holes are used. There are hole types at the mutually facing sides of the glasses connected with the nose
bridge, which holes are typically entirely in parallel with the datum line. In addition, in the temporal side of the glass there are established holes for mounting the side bars, and these holes will typically be situated on a line forming an angle N relative to the datum line of the spectacle glass. It will be presupposed that said second and third cutout for guiding accommodation of the rear edge of the jig are adapted in accordance therewith, and the establishing of the second and third cutout in templates is precision work.
Furthermore, it is noted that it is preferred that the centre axis in the drilling jig holes in the drilling jig are oriented perpendicularly to the underside face of the drilling jig.
Hereby is achieved that holes drilled by using the jig will always be oriented perpendicularly to the contact surface of the spectacle glass against which the underside face of the drilling jig is disposed.
With the purpose of further achieving a particularly effective securing of the drilling jig during establishment of the mounting holes in the spectacle glasses, the jig, which is constituted by a body with at least one, preferably two, through-going drilling holes for guiding a drill, may advantageously be adapted so that the body of the jig furthermore includes at least one projecting means interacting with the second and third cut- outs in the jig, in its half facing away from the periphery of the spectacle glass, the means being oriented at an angle Ni relatively to a imaginary line between the centre of the holes in the through-going holes of the drilling jig and transversely of the centre axes of the said holes.
Hereby is achieved the advantage that the jig quickly and effectively may be placed in the jig in which the spectacle glass is disposed, and furthermore the jig is secured against slipping in the second and third cutouts during drilling the mounting holes in the glasses. In that connection is to be mentioned that it is presupposed that second and third holes preferably are thus formed for accommodating the rear edge of the jig equipment and projecting means, so that the jig by placing in the said cutout is pressed firmly into the cutouts.
It is also well-known that different shapes and outlines are used on the spectacle
glasses used for frameless spectacles and of course also for common spectacle frames. In that connection, there are typically template sets including a plate in which is found cutouts corresponding to outlines of templates laid into said cutouts for use in forming the spectacle glasses.
By the invention it has thus been realised that said templates including a plurality of different spectacle glass shapes may be used in connection with the jig equipment according to the invention, as the already known templates are provided with the said second and third cutouts for guiding accommodation of a drilling jig that may be pro- vided with projecting means which interact with the second and third cutouts in the templates.
In a particular embodiment, the drilling jig can be made of a moulded. Hereby is achieved that a drilling jig piece can be used as a kind of disposable article that is only used by establishing the holes in connection with making of a single pair of frameless spectacles, after which the drilling jig piece is discarded. The advantage of this is that new, unused drilling jig pieces are used for making a frameless spectacle at any time, implying a very high degree of precision in connection with establishing the holes in the spectacle glasses. The moulded items may advantageously be made as moulded items of plastic, reducing the cost considerably in relation to the prior art jigs including metal bushings.
Furthermore, it is preferred that the angle Ni between the means projecting from the drilling jig and an imaginary line between the centre of the drilling jig holes of the drilling jig and transversely to the centre axes of the holes is 90°.
In a further embodiment of the drilling jig, the projecting means may be constituted by a pin inserted therein.
With the purpose of reusing the drilling jig according to the invention for establishing the holes in the spectacle glasses in making a plurality of spectacles, the drilling holes can be provided with bushings of a hard, durable material. The said bushings may advantageously be made of carbide alloy or similar for attaining great wearability, and
hence long service life.
By the invention there is thus provided an even very attractive tool for use in performing a new and relatively unknown method for establishing mounting holes in glasses for frameless spectacles which will enable a quick, efficient and precise effecting of the establishing of the said mounting holes, and which will reduce the percentage of error of glasses with incorrectly disposed mounting holes.
Description of the drawing The invention is explained more closely in the following with reference to the drawing in which:
Fig. 1 shows the prior art tools for use in connection with establishing mounting holes in glasses for frameless spectacles, Fig. 2 shows a template known per se for checking the shape of spectacle glasses,
Fig. 3 shows a template for use in forming spectacle glasses and the control template shown in Fig. 2 provided with a second and a third cutout for a jig according to the invention, Fig. 4 is a perspective view of a jig according to the invention, Fig. 5 is a perspective view of a jig according to the invention shown fitted with a spectacle glass, Fig. 5 A is a sectional view of a drilling jig with spectacle glass and drilling hole jig inserted close to the datum line of the spectacle glass, Fig. 5B is a sectional view of a drilling jig with spectacle glass and drilling hole jig inserted a distance from the datum line of the spectacle glass,
Fig. 6 is a perspective view of a spectacle glass with drilled mounting holes,
Fig. 7 shows different shapes of spectacle glasses and a jig equipment according to the invention, Fig. 8 shows a jig equipment including a plurality of spectacle glass outlines, and Fig. 9 is a detail of the template shown in Fig. 8 with inserted jig and a spectacle glass during establishing the mounting holes.
In Fig. 1 is shown the tools presently used for establishing mounting holes 2 in specta-
cle glasses 4 on frameless spectacles. The tool is constituted by a jig 6 shown from different angles in Fig. 1, a drill for drilling the mounting holes in the glass, a grinding tool for countersinking the holes drilled, mounting pins 38 for mounting nose bridge and side bars in the drilled mounting holes 2 in the glasses 4, special embossing pin- cers for fastening the mounting pins, and a dismounting tool 42 for dismounting nose bridge and side bars, respectively, by pressing out the mounting pins 38.
As it appears, the jig 6 includes a block-shaped body 7 at which is provided a projecting curved portion 9 with a line 11 embossed in the material, the line 11 being situated in continuation of a line between two through-going bushings 8 in the body 7. By establishing mounting holes in the spectacle glasses for the nose bridge by placing the jig at the periphery 18 of the glass and with the line 11 extending in parallel with the datum line 10, after which the mounting holes are drilled under manual holding of the jig. It goes without saying that this opens for great error sources as already noted in the introduction of the description.
In Fig. 2 is seen a template 16 known per se for checking the shape of a spectacle glass 4 by placing this in the cutout 17 in the template 16.
In Fig. 3 is seen a template 43 for use in formation of the shape of a spectacle glass, where the position of the datum line 10 is indicated with the broken line. In Fig. 3 is furthermore show a control template 16 which according to the invention is provided with a second cutout 22 and a third cutout 24 along the periphery 20 of the first cutout 17 at the template 16.
In Fig. 4 is shown a drilling hole jig 6 according to the invention, constituted by a body 7 in which is provided through-going bushings 8 which in the shown embodiment are provided with bushings 8' lying on a line 32 that is oriented perpendicularly to a means 30 projecting from the body 7, the means being constituted by an inserted pin 30' in the shown embodiment at the rear edge 26 of the body. In the embodiment shown, the guide pin 30 is oriented orthogonally to the centre lines 34 of the bushings and a line 34 drawn between said centre axes 34, respectively. However, it is to be emphasised that the means (30, 30') projecting from the body may very well, in other
embodiments, form an angle Vι between the centre lines 34 of the bushings and a line 34 drawn between said centre axes 34, respectively.
In Fig. 5, a jig 6 is shown inserted in the third cutout 24 in the control template 16, ready for drilling the mounting holes 2 in spectacle glass 4 inserted in the hole 17 of the control template 16. Here it is seen that it is about establishing mounting holes for a side bar (not shown) as the line 32 drawn through the centre axes 34 in the bushings 8 forms an angle N with the datum line of the spectacle glass. As indicated, the jig 6 is held in a very effective way whereby drilling of the mounting holes can be effected without risk of the jig 6 sliding at the front side 12 of the glass 4 inserted in the control template 16.
Particularly appearing from Figs. 5A and 5B, in the shown embodiment the centre axes 34 of the bushings are oriented perpendicularly to the underside face 9 of the body 7, which by using the drilling hole jig 6 according to the invention is brought in contact with the facing side of the spectacle glass 4 in which mounting holes 2 are to be drilled. Hereby is achieved that the drill 14 for is guided in the bushings 8 perpendicularly to the upper side of the spectacle glass during drilling of the mounting holes 2 for establishing the mounting holes 2 in the spectacle glass 4, that being independent of where on the spectacle glass 4 the drilling hole jig 6 is disposed in relation to the datum line 10 of the glass, which is important for correct orientation of the nose bridge as well as side bars.
In Fig. 6 is shown a close-up perspective view of a glass 4 provided with drilled mounting holes according to the method and with the tool according to the invention.
Fig. 7 shows a number of spectacle glasses 4 with different embodiments and the jig equipment 16, 6 with a spectacle glass 4 inserted.
In Fig. 8 is shown a control template 16 including a plurality of shapes of glasses, where the first cutout 17 in the templates is provided with a second cutout 22 and a third cutout 24, respectively, for guiding accommodation of a jig 6 according to the invention, which is shown in Fig. 4 and others.
Fig. 9 shows a detail of the control template shown in Fig. 8 with spectacle glasses 4 in the opening 17 of the control template, where the periphery 18 of the glass is following the periphery 20 of the first cutout 17, and a jig 6 according to the invention is inserted in the second cutout 22 at the periphery 20 of the first cutout. Thus it is ready for drilling the mounting holes 2 in the spectacle glass 4. In connection with making spectacle glasses, typically there will be a left and a right glass, and for this purpose the same template may be used as the template is just rotated 180° when shifting from left to right glass 4. By establishing mounting holes 2, it will be possible to use the jig 6 in the same way by inserting this in the second and third cutout. It is noted that the second and third cutout in the control template 16 are thus established so that the hole template is to be pressed down into the said cutout, as it is hereby achieved that the jig is placed in guiding accommodation in the control template.
Finally, it is to be noted that the inventor has realised that the jig equipment can as- sume other forms that those which are shown in the aforedescribed and in the embodiments shown in the drawings. For example, the drilling jigs 6 can be made as moulded plastic items and be used as dispensable matter which is only used once or a few times by drilling the holes in the glasses of a frameless spectacle, after which the drilling jig is discarded. Besides, the means 30, 30' projecting from the body of the drilling jig may also be moulded in one piece with the body in connection with the moulded item constituting the drilling jig.
However, this does not change the inventive aspect wliich is consisting in that with a precision cutting in a control template for checking the shape of spectacle glasses, it is enabled to position a jig interacting therewith in such a way that the jig is held in the
100% correct position during drilling of the mounting holes 2 in the spectacle glasses 4, and without it being necessary to perform a marking of the datum line at the front side of the spectacle glass.
List of position numbers
2 mounting holes 4 spectacle glass 6 drilling jig
8 through-going bushings in drilling jig 10 datum line 12 front side of the glass 14 drill 16 holes in glass
17 first cutout in template 16
18 periphery of glass
20 periphery of first cutout 17
22 second cutout in periphery of first cutout 24 third cutout in periphery of first cutout
26 rear edge of jig
28 half of drilling jig facing away from periphery of glass
30 guide pin
32 line between centres of jig holes 34 centre axis of bushings
36 grinding tool for countersinking holes in glass
38 assembling pins for assembling fittings and glasses
40 squeezing pincers for assembling pins 38
42 dismounting pincers for assembling pins