DE1652934A1 - Abrasive pad and process for making it - Google Patents

Description

5454

Univis, Inc. Fort Lauderdale, Florida, USA _e

Abrasive pad and method of making it

33 = SS =

The invention "relates to a method of manufacture an exchangeable Schielf support for a lens grinding tool, which has a surface for grinding optical lenses and eyeglasses.

Optical lenses and eyeglasses are commercially available by precisely grinding a lens blank to a predetermined one Curvature produced, whereby the lens the desired optical qualities are given. The generally with a tool made of cast iron or the like, which is provided with a lapping surface, the Curvature corresponds exactly to the curvature that the lens blank surfaces should receive. During the grinding process, a grinding fluid is applied to the lapping surface applied, and between the lens blank and the lapping surface there is a relative rotational movement, an oscillating one Movement or a combined rotary and oscillating movement is generated. Since the lapping surface of the grinding tool as well the lens blank the grinding effect the grinding fluid

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it is readily apparent that it wears out fairly quickly, so that in quick succession A dressing or reworking is necessary at intervals so that the lapping surface is again the desired one Gets curvature. It is therefore desirable to have a replaceable grinding surface for such a grinding tool to create, and numerous attempts have been made to produce a suitable interchangeable pad, that has such a grinding surface «This one However, attempts are all liable to one or the other defect. The main difficulties are in the standardization of the Support exactly with the desired curvature, -in the upright position Maintaining a sufficient binding of the edition to the tool and the short service life (service life) of such conditions.

There is accordingly a need to manufacture a economical and powerful interchangeable grinding pad for a lens grinding tool that is easy is interchangeable, has a precise curvature and can be securely or properly attached to the grinding tool. It a method for producing and replacing such editions should also be specified.

The invention consists essentially in the fact that a sanding pad or a sanding pad directly

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"bar above the surface of the grinding tool that determines the curvature is trained. A flat blank of metal or other suitable material is placed between these Surface of the grinding tool and a form or embossing block inserted, which is filled with an elastic material is. The tool is then pressed against the blank and into the elastic material under relatively high pressure, wherein the blank is deformed in such a way that it adapts to the curvature of the surface.

In the preferred embodiment of the invention is The overlay is slightly smaller than the one that defines the curvature Surface of the tool, and between the tool and the support can be a pressure-sensitive adhesive coating or contact adhesive be introduced in order to achieve a corresponding binding or fastening while the tool is in use to obtain.

In the manufacture of supports for grinding toric eyeglasses, it has been found that the formation of an intermediate spherical shell may be necessary before the final tor loche shape is formed when the sheet metal blank, from dom the support nv '/, \ i "e -hi _t -en eats, is relatively thick and inflexible this purpose v / i l'd in dor "vveise described above, a flat UV Metallroh- ^1;. 'VVJ £ jf forth your spherical end ei nan L ^ enipels and a K ¹ Uf _- Ot I-: '·; ο '. Ti, oil e / 't, the with; ο in ο in <- .: --Int i raw vveri: st "ff

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is filled. The punch is then pressed against the blank and into the elastic material, whereby the blank is deformed into a spherical shell. The shell is then inserted between a grinding tool with the desired toroidal curvature and an embossing block, the is filled with an elastic material. The grinding tool is then against the shell and into the elastic Material pressed in, with the result that the shell is deformed into the desired toroidal shape. the Interposed spherical shell can be made somewhat larger than the toroidal attachment of the grinding tool. In this case, when the final sanding pad is made, the excess material can be conveniently bent over so that there is a circumferential direction Forms retaining edge that secures the sanding pad at the sanding attachment while the tool is in use.

As already mentioned, while the tool is in use, a grinding liquid is applied over the grinding surface of the Tool distributed. The tool can thereby be used for grinding or polishing lenses, depending on on the particle size and the grinding ability of the grinding fluid used. So that this grinding fluid Evenly distributed over the lapping surface, the metal blank can be made with a series of cutouts or slots are provided as feed channels

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serve when the support is attached to the grinding tool. The slots also ensure when properly positioned and shaped, an abrasive pad that has an abrasive pattern with a curvature that will last over its life remains essentially unchanged and enables the grinding of shaft-free lenses.

The invention will now also be described in detail with reference to the accompanying drawings, all of which are taken from the description and the details or features shown in the figures for solving the problem within the meaning of the invention can contribute and were included in the application with the intention of being patented. Show it:

Pig. 1 is an exploded partial sectional view of an embossing block and press for making abrasive pads according to the invention;

Pig. 2 one of the pig. 1 similar view after the pad is formed;

Pig. 3 is a cross-sectional view of Pig. 2 manufactured Edition;

Pig. 4 one of the pig. 1, according to which an intermediate spherical shell is used as the workpiece is made to toric abrasive pads according to another Manufacture embodiment of the invention;

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Pig. 5 one of the pig. 2 similar view that the actual Shows manufacture of the toric overlay;

6 is a partial sectional view of a grinding tool which is attached to a sanding pad by means of a binding agent is;

7 is a partial side view of a grinding tool which has a grinding pad made according to the other embodiment of the invention around its lapping surface is arranged around, wherein the support is provided with a peripheral edge that the support on the grinding tool specifies;

FIG. 7a shows a view of the grinding support according to FIG. 7 from below; FIG.

8 shows a partial sectional view of a forming or embossing block and a press for producing concave sliding surfaces;

Fig. 9 is a top plan view of a tool with a plurality is provided by embossed grooves which are covered by a grinding pad according to the invention, wherein the grooves in the tool are formed on the support;

Fig; 10 is a plan view of a metal blank which is particularly useful for making an interchangeable support for Grinding spherical surfaces is suitable;

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Pig. -11 a plan view of an embodiment of a metal blank, which is particularly suitable for making an interchangeable support for sanding toric surfaces;

Pig. Figure 12 is a top view of another embodiment a metal blank for grinding toroidal surfaces;

Fig. 13 is a plan view of another. Embodiment a metal blank for grinding toric surfaces and

Figure 14 is a partial sectional view of a forming or embossing block and a press for forming a continuous grinding support around a grinding wheel according to the " Invention.

Referring now to the drawings, in particular to Fig. 1, there is shown an apparatus 10 for carrying out the method according to the invention. The device 10 contains a viscoplastic material 12 which is enclosed in a mold or embossing block 14. The resilient material 12, which may be made from a natural, resilient elastomer such as rubber or various rubber compounds, or from a synthetic elastomer such as polyurethane, forms an opposing shape for the compact or punch 16 in operation of the device. The compact 16 can be hydraulically operated (the hydraulic device is not shown), and according to the invention can

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the molding or embossing portion 18 of the compact 16 may be spherical, toric, or any other desired Have shape and curvature. The distance between the embossing block 14 and the pressing body 16 is determined so that the Pressed body is pressed into the elastic material 12 of the stamping block when the hydraulic press is in operation occurs.

To carry out the invention, a flat grinding support blank 20, which consists essentially of a thin plate or disk made of steel or other metal, is inserted between the elastic material 12 and the pressed body and aligned relative to the pressed body. In the preferred embodiment of the invention, the upper surface of the blank and the lower or embossing section 18 of the pressing body 16, which has the surface of a grinding tool defining the curvature, are previously coated with a suitable contact adhesive of sufficient adhesive strength to form the pad To hold the shape on the tool so that it can withstand the stresses of grinding. The press is then put into operation so that the press body advances against the die block, the blank 20 being deformed so that it conforms to the shape of the lower portion 18 of the press body 16. The arrangement shown in FIG. 6, which consists of the tool 38, the adhesive 44 and the support 30, is thereby formed.

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The slider pad according to the invention can be on the individual Abrasive tools shaped and used in conjunction with them shown in Figs. 6 and 7, or it can be used in conjunction with a grinding wheel 52 shown in Figure 14. In the latter Case can be a series of supports around the circumference of the grinding wheel 52 end-to-end in the same manner be formed as described above, using the disc as a pressed body for each support, or a continuous support 30c can be formed by using a blank 56 of sufficient length and the disk 52 is rolled against the blank and into a resilient disk 54 with sufficient pressure around the To deform blank in the manner described above. The device for performing the last mentioned procedure is shown in FIG.

In one successful operation of the process described above, cold-rolled, deep-drawn sheet steel blanks have been produced with a maximum Rockwell hardness of B 55 and a thickness between 0.005 and 0.01 inches (0.127 to 0.254 mm) deformed into supports under a pressure of between 20 and 25 tons. The elastic contained in the embossing block 14 Material 12 consisted of an "Elasta Gast Polyurethane Elastomer" available from the Acushnet Process Company of Hew-Bedford, Massachusetts, USA. Satisfactory

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Similar results have also been achieved by using a hydrostatic "pocket" which consists of a liquid-tight, non-elastic envelope which is filled with a non-compressible liquid as the elastic material. A suitable adhesive is supplied by Minnesota Mining and Manufacturing Company as senior No. ₀ 1357th This is a contact adhesive that is supplied in liquid form and applied to the surfaces of the tool and the support to be connected according to the manufacturer's instructions.

8 shows an apparatus for producing concave supports according to the invention. The elastic material 12b enclosed in the embossing block 14b contains a hemispherical dome 40 which protrudes against the pressed body. The radius of the tip 40 is smaller than the shortest radius which is to be formed on the support 20b. In all other respects the device and the method correspond to that described above for the formation of convex supports.

A modified method of practicing the invention has been found to be very useful in the manufacture of relatively thick editions or editions made of less flexible materials. In this modified procedure a spherical intermediate shell is first formed, and the intermediate shell is then processed further and converted into the desired form. Here, in the

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In the manner described above, a spherical shell 30a can be produced using a spherical tool with an embossing section 18. It is now on Pig. 4 referenced. The spherical shell 30 is then between a second pressing body 16a and inserted stamping block 14a, which is filled with an elastic material 12a _e The embossing block used in this second process step may be the same that was used in the first process step, and it fulfills the same Function.

The embossing section 18a used in this second pressing step consists of a tool which has the desired toric shape or spherical curvature, and therefore when the device 10a is brought into the position shown in Fig. 5, is the shell 32 produced in this way to the toric or spherical curvature of the tool 18a adapted «,

In the modified embodiment according to FIGS. 4 and 5, the spherical intermediate shell 30a, which during of the initial pressing process is produced, slightly larger than the grinding tool that is produced in the second pressing step serves as the embossing section 18a. Therefore, as shown in Figs. 5, 7 and 7a, when the second pressing step is completed, is the holding or fastening flange 34 from the excess Material formed. This flange 34 is used to attach the shell 32 to the grinding tool 38 by

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he rubs against the side wall of the grinding tool ~ lies.

It can thus be seen that the deformed blank is a support around the grinding surface of the grinding tool 38 and the outer surface 42 of the support thereby as an exchangeable one The grinding surface for the grinding tool 38 is used. If the sanding surface of the sanding pad due to the Abrasive action of the abrasive used in the lens grinding process can affect the entire Overlay can easily be removed from the grinding tool and a new overlay can be made according to one of the above Operations are applied.

The blank 20, from which the grinding pad is formed, can be made from sheet steel or any material that has the appropriate pliability to deform and has suitable properties for grinding glass. Stamped sheet steel blanks with thicknesses varying between 0.005 and 0.01 inches (0.127 to 0.254 mm) have given particularly good results. The fact that the blank 20 with a multitude of slots and cutouts is provided in various geometric arrangements, the abrasive pad made from such a blank has desirable wear and abrasive fluid distribution properties be awarded. It is particularly desirable to produce a shoe sole that has a scuff pattern

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"has its curvature during the life of the pad remains essentially unchanged and which enables the grinding of shaft-free lenses. The figures 10 to 13 show various embodiments that the blank 20 before it is converted into a grinding pad can have and with which satisfactory results have been achieved.

The Pig. 9 shows a tool having a plurality of impressed grooves 46, which is provided with a tool on the tool according to the invention designed grinding pad 20a is provided, the grooves in the support being formed by the elastic effect of the elastic material 12 are. The embossed grooves serve as channels for distributing the grinding fluid.

The support 20b shown in FIG. 10 is particularly suitable for producing spherical grinding supports. she is fairly circular and symmetrical about the diameter defined by slots 48b and 49b. A plurality of radially inwardly extending slots are provided including the T-shaped slot, which includes sections 51b parallel to the axis of symmetry and a section 50b perpendicular to the axis.

The irregularly shaped support 20c shown in FIG. 11, which is provided for grinding toric lens surfaces

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is also symmetrical, constructed about the major axis passing through the center of slot 48c, and also includes a plurality of inwardly directed slots and cutouts including slots 49c that are parallel to the major axis and slots 50c and cutouts 51c that are directed towards the center of the support. The support 20c is essentially octagonal in shape, the opposite sides 53 and 55, through which the major and minor axes extend, are provided with V-shaped cutouts which point towards the center. The cutouts located in the sides 55c and 55c ¹ run from one end of the corresponding side to the other, while the cutouts located in the sides 53c and 53c 'run out between the ends.

The edition 2Od, which was published in Pig. 12 and is also provided for grinding toric surfaces, consists of a substantially rectangular body with major and minor axes and a series of grinding fluid distribution slots 48d, which are arranged symmetrically about a diagonal. The slots run alternately inside, starting from one side of the axis of symmetry and then from the other side.

The support 20e shown in FIG. 13 is similar to that of FIG. 12 with the exception that the slots 48e run fairly parallel to the minor axis.

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In addition to helping with the distribution of the grinding fluid, the sections described above make it easier also the exact adaptation of the support to the tool during the pressing step. It has been shown that when using such cut-outs the force of 20 to 25 t required for the correct formation of the support (without cut-out " te) can be reduced to 5 to 10 t (with cutouts).

It is therefore readily apparent to a person skilled in the art that the above teachings provide an economical and powerful method of making interchangeable Include abrasive pads for a lens grinding tool that are accurate and inexpensive.

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Claims (24)

Patent claims 1. Method of making an interchangeable abrasive pad for a lens grinding tool that has surfaces for grinding optical lenses and eyeglasses, characterized by inserting a metallic grinding support blank between a with an elastic material-filled embossing block and a stamp and then deforming the blank Pressing the punch against the blank in the elastic material in order to deform the blank so that this receives a surface shape which corresponds fairly to that of the stamp. 2. The method according to claim 1, characterized in that the punch has a concave surface shape and the elastic material includes a hemispherical dome portion extending in the direction of the Stamp extends, and that the radius of the dome is smaller than the shortest radius of the stamp. - 16 - 109818/0417 3. The method according to claim 1, characterized in that a spherical stamp is used is to produce a support for a toroidal grinding tool, wherein the deformed blank is an intermediate shell with the curvature or curvature of the spherical punch, and that the intermediate shell between the toric Inserted the tool body and an embossing block filled with an elastic material and pressing the Shell in a block filled with elastic material together with the toric grinding tool further deformed is that an interchangeable pad is formed which has the same shape as the toric tool. 4. The method according to claim 1, 2 or 3, characterized in that the stamp and the Tool can be driven into the elastic stamping block by a hydraulic press. 5. The method according to claim 1, 2, 3 or 4, characterized in that as elastic material a polyurethane elastomer is used. - 17 - 109818/0417 6. The method according to claim 3, 4 or 5, characterized in that the Intermediate shell formed larger than the toroidal grinding tool and the excess material is formed into a retaining flange around the peripheral edge of the toric grinding pad which is formed by pressing the toroidal tool into the intermediate shell, the peripheral flange comes into friction contact with the toric tool and secures the support on the tool. 7. Exchangeable grinding pad for grinding lenses produced according to the process according to claims 1 to 6, characterized in that the Abrasive pad (30) is formed around the surface (18) of a grinding tool (38) with which the pad is used, and that the grinding pad (30) has a grinding surface (42) with essentially the same shape and curvature as the grinding tool and devices (46, 48, 49,50,51) contains an amount of an abrasive fluid mixture take in, hold and distribute. 8. Interchangeable grinding pad according to claim 7, characterized in that the Support includes a coupling device (34) to connect the grinding support to the tool (38). - 18 - 109018/0417 9. Exchangeable sliding pad according to claim 7 or 8, d ~ - cur.ch marked that the K-, "* gseinrichtung one around the circumferential edge of the edition (32) arranged holding flange (34), wherein the diameter of the holding flange is determined such that the support (32) in friction contact with the grinding tool (38) can come. 10. Exchangeable slip pad according to claim 7 or 8, characterized in that the support (20b) consists essentially of a circular body (Pig. 10) which is symmetrical about a diameter and that the portion holding the grinding liquid is surfaces contains, which limit a plurality of slots (48b, 49b) which extend radially from the circumference of the support extend inside, including a T-shaped slot (50b, 51b), of which parts perpendicular to the axis of symmetry and other parts run parallel to this. 11. Exchangeable sliding pad according to claim 7 or 8, characterized in that the support (20c) consists of an irregularly shaped body (Fig. 11) with major and minor axes and that is the sole fluid holding section contains surfaces that have a multitude of diagonal slots extending from the perimeter edge against the Extend middle of the support, as well as limit a plurality of slots (49c), which are parallel to the main axis from the edge against run down the middle of the support. 1öb2934 12. Exchangeable sanding pad according to claim 7, 8 or 11, characterized in that the portion holding the grinding fluid includes surfaces, the one further slot (48c) extending from one edge of the support (20c) along the main axis over the main part the same runs, as well as a plurality of V-shaped cutouts limit, which are from the edge of the support against extend the center inward. 13. Exchangeable sanding pad according to claim 11 or 12, characterized in that the support (20c) has an octagonal shape that the main and Minor axes run through the center of the opposite sides (53c, 53c ', 55c, 55C) of the octagon and that the V-shaped cutouts delimiting surfaces are arranged on the opposite sides. 14. Exchangeable grinding pad according to claim 13, characterized in that the Faces that delimit the V-shaped cutouts on the sides through which the main axis runs, extend from one Extend end of that side to the other end. - 20 - 109818/0417 1662934 W. 15. Exchangeable grinding pad according to claim 7, characterized in that the Support (20c) consists of a substantially rectangular body (lig. 13) with a major and minor axis, and in that the means for holding the grinding fluid has surfaces on the support which comprise a plurality of Limiting slots (48e), which are essentially parallel to the minor axis, alternating from one edge of the support and then run inwards from the other. 16. Exchangeable sanding pad according to claim 7, characterized in that the support (20d) consists of a substantially rectangular body (Mg. 12) with a major and minor axis and that the grinding liquid holding device on the Support has surfaces defining a plurality of slots (48d) which first extend from one side of the rectangular body and then extend diagonally inward from the opposite side. 17. Exchangeable sole pad according to one of the claims 7 to 16, characterized in that the grinding tool and the exchangeable grinding support have toric grinding surfaces. 18. Exchangeable grinding pad according to claim 1, characterized in that the pad forms eyeglasses. 19. Exchangeable sliding support according to claim 7 or 10, characterized in that the support forms optical lenses. 20. Exchangeable grinding pad for a grinding tool body according to one of claims 7 to 19 j characterized in that the corresponding surfaces of the body and the support have the same curvature and shape and are in surface contact with one another. 21 "Exchangeable sanding pad according to claim 20, characterized in that the grinding pad (30) by an adhesive (44) with the Tool body (38) is connected. 22. Exchangeable grinding pad according to claim 20, characterized in that a Grinding attachment forms a section of the circumference of a grinding wheel and a plurality of the same grinding attachment is arranged around the entire grinding wheel circumference. 23. Exchangeable grinding pad according to claim 20, characterized in that the The grinding attachment consists of a disc (52) and the support (30c) is arranged around the entire peripheral edge of the disc is. 1QÖÖJ I6b2934 24. Interchangeable sole pad according to claim 20, characterized in that the Grinding attachment (20a) a major and minor axis as well as a Includes a plurality of embossed channels (46) parallel to the axes, the channels carrying the abrasive fluid mixture take over and hold. - 23 109818/0417 Blank page