US2612734A

US2612734A - Apparatus for grinding the bevel edge of spectacle and other lenses

Info

Publication number: US2612734A
Application number: US125741A
Authority: US
Inventors: Taig William Adams
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-10-25
Filing date: 1949-11-05
Publication date: 1952-10-07
Anticipated expiration: 1969-10-07
Also published as: GB656690A

Description

Get. 7, 1952 w. A. TAIG APPARATUS FOR GRINDING THE BEVEL EDGE OF SPECTACLE AND OTHER LENSES 2 SHEETS-SHEET 1 Filed Nov. 5, 1949 M I n M 4. M 1 QM mum M Q 1 Fi WmAMW| H mm 9 mm 3% Vm Q w Q e p, sh mm an mm h MN fikmm no bhvh Ill vfldlmll A av R mvozwwwwu ob Q? n E on mm N m ct. 7, 1952 w. A. TAIG 2,612,734

APPARATUS FOR GRINDING THE BEVEL' EDGE OF SPECTACLE AND OTHER LENSES Filed NOV. 5, 1949 2 SHEETSSHEET 2' Patented Get. 7, 1 952 UNITED STATES PATENT o rr cs APPARATUS FOR GRINDING THE BEVEL EDGE LENSES OF SPECTACLE AND OTHER William Adams Taig, Farnham, England Application November 5, 1949, Serial N '0. 125,741 In Great Britain October 25, 1948 in a predetermined position, particularly, as is most prevalent, when the lens is not exactly round, without suitably shaping the groove in the wheel.

In the case of a meniscus or toric lens shaped to present day style with a considerable difference in width and height, that part of the lens which is nearer to the centre than the remainder will be curved on the edge when looked at edgewise and in such cases the apex of the bevel may be formed to one side or the other. at different places around the lens.

The object of my invention is to provide a solution of this problem and to provide an apparatus which is more efficient than those at present in use and one which in edgingmain tains the apex of the bevel in a predetermined position.

According to the present invention apparatus for grinding the bevel on the peripheral edge of spectacle and other lenses is provided wherein axial movement is imparted to the lens during grinding to maintain the lens in correct position relative to the bevel grinding surfaces.

During grinding the lens is caused to move towards and away from the bevel grinding surfaces in accordance with the peripheral contour of the lens, and, preferably, the axial movement is effected as a result of this lens shaping movement,

An apparatus according to this invention comprises in combination grinding means for forming the bevel on the peripheral edge of the lens, lens supporting means for holding the lens in contact with the grinding surfaces of the grinding means, said supporting means imparting rotary movement to the lens, means for imparting axial movement to the lens supporting means to maintain the peripheral edge of the lens in correct alignment with the bevel grinding surfaces, .and means for causing displacement of the lens supporting means to cause the lens to advance towards and recede from the grinding surfaces in accordance with the peripheral contour of the lens to produce the finished shape.

The combined axial movement of the lens 11 Claims. (Cl. 51-101) supporting means and its displacement towards and away from the grinding means may be effected by cams, the profile of one of said cams corresponding to the finished peripheral shape of the lens, this cam being rotatably mounted and, during its rotation, effecting the desired displacement'of the lens supporting means, The shape of the othercam corresponds to the curvature of the face of the lens, and, preferably, the

axial movement imparted ,to the lens supporting means by this cam is effected through a cam follower.

The grinding means preferably comprises two grinding wheels which are mounted separately and at an angle to one another, the peripheral grinding surfaces of the two wheels being positioned to produce the desired bevelled surfaces on the edge of the lens. 3

With the construction according to the present invention grinding at high speed can be effected as both the lens and the grinding wheels are securely mounted in position. I

In order that the invention may. clearly be understood and carried into effect an embodiment of the same will now be described with reference to the accompanying drawings in Fig. l is a front elevation, partly in section, of apparatus according tothe invention.

Fig. 2 is a plan view of Fig. l.

Fig. 3 isa sectional view taken on the line 3-3 of Fig. -1 and Fig. 4 is an end view taken on the line 1774 of Fig. 2.

In the apparatus shown in the drawings the bevelling of the edge of the lens I is effected by two grinding wheels 2, 3 each of which is secured on a driving spindle, each spindle being rotated through a belt drive, not shown, by associated pulleys 4, 5 the spindles being carried in pedestal bearing brackets 6 secured by clamping nuts I to a machine bed.(not shown) upon which the apparatus is mounted.

The grinding wheels are set at an angle to one another,- the anglebetween the peripheral grinding edges of the-wheels corresponding'to the angle of the bevel to be formed on the edge of the lens.

As shown the lens supporting means consists of two spindles 89 each of which is mounted co-axially in bearing sleeves ID-l l forming part of a bracket l2.

The opposing end of each spindle is provided with a ferrule I3, a thrust bearing [4 being interposed between each ferrule and its associated spindle, and each ferrule is provided at its end with a pad of rubber or other resilient material between which the lens to be ground is gripped.

The spindle 8 is slidable in its bearing sleeve and is urged towards the spindle 9 by a spring 16 surrounding the outer end of the spindle 8, one end of the spring being in engagement with a peripheral shoulder 11 formed on spindle 8, the opposite end of the spring engaging a bush [8, that is rotatable on the spindle 8, said bush l8 being fixedly secured to the sleeve 2|.

The action of the spring I 6 on spindle 8 is controlled by rotation of a hand wheel 20, said rotation in one direction permitting the spring to urge spindle 8 towards the spindle 9 and rotation in the opposite direction effecting movement of the spindle in the opposite direction to permit removal of a finished lens and insertion of a further lens to be bevelled.

For the above purpose the hand wheel 28 is pinned to the outer end of a sleeve 2|, the inner end of which is provided with-an internal flange 22 which engages with the shoulder I? on spindle 8 to provide an abutment to control the inward axial movement of spindle B.

The sleeve 2| is threaded externally, the thread 23 engaging with an internal thread 24 formed in a bush 25 secured in the bore of a housing 26 forming an extension of the bearing sleeve, the arrangement being such that rotation of the hand wheel 20 in one direction effects inward movement of the sleeve 2| to permit the spring IE to urge the spindle 8 axially towards thespindle 9, and rotation of the hand-wheel 20 in the opposite direction causing the sleeve 2| to move outwardly, and, through the shoulder l1 and flange 22, to move the spindle 8 axially outwardly.

The lens is rotated by the positive rotation of the spindle 9 and for this purpose this spindle is provided with a driving pulley 21 which is driven through a belt drive, not shown.

Displacement of the lens towards and away from the grinding surfaces of the grinding Wheels is effected by imparting a rocking movement to the lens supporting means by acam the profile of which corresponds to the finished peripheral shape of the lens, the cam operating against. the action of a spring which urges the lens supporting means towards the grinding wheels,

For the above purpose the bracket i2 is mounted on a shaft 28 by two pairs of arms 29 and'36, which are secured by their upper ends to the brackets by headless conical point screws 3| and lock nuts 32, the lower end of each pair of arms being similarly secured by further headless conical point screws 33 and lock nuts 34 to

hearing blocks

35, 36 respectively, which are carried by, and keyed to, shaft 28, the said shaft being in turn mounted in spaced bearings 31 supported by the machine bed.

To permit a positioned lens to be adjusted laterally between the grinding surfaces, the lens supporting means is movable as a whole in a lateral direction by effecting a similar movement of the shaft 28.

For this purpose the shaft 28 is urged in one direction by a compression spring 38 which surrounds the shaft, the spring being compressed 'between one end of one of the shaft bearings 31 and a collar 39 secured to shaft 28. The shaft is movable against the spring action by operation of a hand wheel 40 having a threaded spindle 4|, the threaded spindle bein mounted in the threaded bore of a block 42, the end of the spindle 4| projecting through the block 42 and into a bore formed in the end of the shaft 28, this bore being provided with a thrust ball 43 against which the spindle end abuts.

The rocking movement of the lens supporting means is obtained from the rotating cam 44 which is detachably mounted on a spigot 45 projecting from one end of spindle 9, the cam urging the lens supporting means away from the grinding wheels against the action of a spring 4411 one end of which is attached to the sleeve Hi the opposite end being anchored to a stud 44b carried by the machine bed.

The cam rotates with spindle 9 and is connected in driving engagement therewith by two driving pins 46 which project outwardly from a bush 4'! mounted on the spigot 45, the driving pins passing through holes provided in the cam.

The cam is maintained laterally in position on the spigot 45, by a headed plunger, the head 48 of which is pressed against the opposing face of the cam by a compression spring 49 one end of which engages with the opposing end of the stem 50 of the headed plunger, the opposite end of the spring engaging with the inner end of a bore 51 formed in a sleeve 52 in which the stem 50 of the headed plunger is slidably mounted, the sleeve 52 being fixedly mounted in a bearing 53 carried by the bracket l2 of the lens supporting means.

As shown in the drawings, the headed plunger has been forced back against the action of spring :39 to permit the cam 44 to be removed and replaced by a further cam.

The periphery of the cam 44 bears against an abutment surface 54 formed on a vertical bracket 55 which is carried by one end of a spindle 55 mounted in a bore provided in a housing 51 which is secured to the bed plate of the machine, and

accordingly as the cam is rotated the lens supporting means will rock with the desired motion according to the shape of the cam profile.

The position of the abutment surface 54 relative to .the edge of cam 44 is variable to permit different sizes of cams to be fitted and for this purpose the spindle 56 is formed at its free end with a micrometer screw thread 5111 on which a micrometer adjusting nut 58 is carried, a compression spring 59 being provided to take up any backlash in the threads.

The micrometer screw may be adjusted as grinding proceeds to effect gradual grinding of the lens to finished size or if preferred the lens may be plunge ground in which case the micrometer screw is adjusted to the finished size of the lens before grinding commences.

Lateral movement of the lens between the grinding surfaces of the grinding wheels is effected by a cam 60 which, as a result of the rocking motion of the lens supporting means, causes the bracket [2 to swing in one direction laterally on the pivot pins 3 l the arms 29, 30 moving similarly about the pivot pins 33, the cam operating against the action of a spring Bl which operates to urge the lens supporting assembly in the opposite direction, the spring being stretched between two posts, one of which Bla is carried by one of the lzgriis 30, the other 6 lb being fixed to the machine I shaft 28, the boss 63 being pinned to the shaft 28 so that the arm 62 and cam 60 rock with the shaft 28.

The cam 66 is provided with a cam surface 64, the shape of which corresponds to the sectional curvature of the lens to be ground and as the cam 66 is rocked lateral movement is imparted to the lens supporting means through a cam follower consisting of a roller 65 which is interposed between the cam 60 and a pressure plate 66 mounted on the free end of sleeve 52, the pressure plate forming part of a boss 61 which bears against one end of the bearing 53 so that as the pressure plate 66 is moved by-the action of the roller 85 the complete lens supporting assembly receives a similar movement.

The roller 85 is carried on a pivot pin 58 mounted on the upper end of an arm 69, the said arm being provided at its lower end with a boss 59a by means of which it is mounted on a further pivot pin it supported in the spaced lugs H forming part of a bracket 12 carried bythe shaft 28. The boss 69a is located on the pivot pin Hi by two rollers Ella.

The shaft 28 is freely rotatable in the bracket l2 which is held against movement by a stud l3 engaging in a support 74 projecting vertically upwards from the machine bed.

The cam 60 is removable so as to be capable of replacement by a further cam the surface of which corresponds to a lens of diiferent sectional curvature. 1

As shown the arm 69 is mounted so that the same may be moved in a direction transversely of the lens supporting spindles 8-9 to permit the roller 65 to be brought into correct registration with the cam surface of cam 68.

For this purpose the pivot pin 78 is threaded for a portion of its length the threaded portion engaging with a thread formed in one of the lugs ll the pivot pin being rotatable to-adjust the position of the roller, by a knurled knob 15.

When it is desired to remove the cam 60 the lens supporting assembly is moved laterally in a direction away from this cam, i. e. to the right, see Fig. l, and for this purpose a cam disc is provided which is mounted eccentricallyon a rotheedge of the lens I towards and away from the grinding wheels 2 and 3, this rocking movement resulting in the correct peripheral shape of the lens-l being obtained.

As the

bearing blocks

35, 36 arekeyedto the;

shaft 28 the same is rotated in opposite directions in accordance withthe rockingmovement of the bracket l2 thereby imparting a similar, motionto the arm 62 and the cam 60 carried on the upper end of this arm.

The rocking motion of the cam 60 imparts through the cam follower. 65 and pressure plate 66 axial movement in the direction to the-lens supporting assembly against the action oftensionspring 6|. As the cam 60 is rocked in one direction-to bringthe high portion of the cammed surfaceinto contact with the-cam follower the said 'ca m follower is rocked-on its pivotal mounting -to-effect through the pressure'plate 66 axial displacement ina direction to the. right of'Fig.

1 of-the lens supporting assembly against the action of the tension spring 61. When the cam is rocked in the opposite direction so that the low portion of the cammed surface is brought v into contact with the cam follower 85 the action of spring 6| pulls the lens supporting assembly in a direction to the left of Fig. 1. The axial displacements of the lens thus result ,in the peripheral edge of thesame beingmaintained in the correct position between the grinding wheels 2 and3. I

When grinding has continued for-a short period the lens should be examined to ensure that the same is beingcorrectly ground, and if necessary the cam 44 can be adjusted by operation of the micrometer adjusting screw 51a to correct any faults which may be apparent in the peripheral shape. of the lens. The cam-follower may similarly be adjusted to correct any faults due to incorrect axial displacement of the lens supporting assembly.

To remove a finished lens from the machine,

after stopping the machine the hand wheel 26- is rotated in a direction to cause the flange 2-2 to form a bevel edge therefor, a pair of grinding tatable pivot Tl carried on a bracket arm 18 projecting from the bracket 12. The edge of the cam disc it bears against a fixed surface 19 forming part of the arm 39 so that as the cam disc is rotated due to its eccentricity the lens supporting assembly is moved laterally and held against the action of the spring 6|.

The machine described above is operated in the following manner.

Cams 6% and 45 having cam surfaces corresponding to the desired finished shape of the lens to be ground are secured ontheir respective mountings and the lens blank I to be ground is positioned between the ferrules I3, the spring [6 operating to hold the lens firmly in position.

Uponstarting the driving motor the lens I is rotated at the desired speed through the belt drive to pulley 21 and spindle 9, and the grinding wheels 2 and 3 by further belt drives to the pulleys d and 5.

As a result of the rotation of the cam 44 secured to the spindle 9 and the engagementof the periphery of this cam with the fixed abutment surface 54, the bracket [2 is rockedte move:

wheels angularly disposed to form by their joint peripheral surfaces a V grindingsurface, means for rotating said grinding wheels, lens support-.

ing means comprising a pairof co-axially aligned spindles biased toward one another togrip alens therebetween, means for rotating said lens sup-. f

porting means, means for pivotally mounting said lens supporting means, a profiling member having a peripheral cam surfacev mounted on the lens supporting means and rotatable therewith, an abutment fixedly mounted for cooperation with the peripheral surface'of said-cammed profiling member, said lens supporting means being rockable about the pivotv therefor, toward and away from the grinding edges of said grinding wheels in accordance with the radius variation of the cammed profiling member, and a cam faced member rockably mounted on the pivot for, and disposed axially and laterally of,

said lens supporting means, and means between i and frictionally contacting said cam faced memher and. said lens supporting-means and pivotally mounted for movement transversely ofthat. of .sa'idi cam faced member and said lens supporting means, said last named means bein adapted, upon rocking of said lens supporting means, to impart an axial displacement thereto corresponding to the contouration of the face of thecam faced member.

2. An apparatus in accordance with claim 1, wherein means are provided for biasing said cammed profiling member toward the abutment and wherein means are provided for biasing said lens supporting means towards the cam faced member.

3. In an apparatus for grinding optical lenses to form a bevel edge therefor, a pair of grinding wheels angularly disposed to form by their joint peripheral surfaces a V grinding surface, means for rotating said grinding wheels, lens supporting means comprising a pair of co-axially aligned spindles biased toward one another to grip a lens therebetween, means for rotating said lens supporting means, a bracket having bearing sleeves respectively mounting said spindles, means for pivotally mounting said bracket, a profiling member having a peripheral cam surface mounted on the lens supporting means and rotatable therewith, an abutment fixedly mounted for cooperation with the peripheral surface of said cammed profiling member, said bracket and the lens supporting means mounted for rotation thereon being rockable about the pivot therefor, toward and away from the grinding edges of said grinding wheels in accordance with the radius variation of the cammed profiling member, and a cam faced member rockably mounted on the pivot for, and disposed axially and laterally of, said lens supporting means, and means between and frictionally contacting said cam faced member and said lens supporting means and pivotally mounted for movement transversely of that of said cam faced member and said lens supporting means, said last named means being adapted, upon rockin of said lens supporting means, to impart an axial displacement thereto corresponding to the contouration of the face of the cam faced member. v

4. An apparatus in accordance with claim 3, wherein means are provided for biasing said cammed profiling member toward the abutment and wherein means are provided for biasing'said lens supporting means towards the cam faced member.

5. Apparatus for grinding the bevel edge of optical lenses comprising in combination, grinding means having grinding surfaces for forming the bevel on the peripheral edge of the lens, lens supporting means for holding the lens in contact with the grinding surfaces of the grinding means, said supporting means imparting rotary movement to the lens, means for causing displacement of the lens supporting means to cause the lens to advance towards and recede from the grinding surfaces in accordance with the peripheral shape of the lens to produce the finished shape, said last-named means'comprising a bracket carrying said lens supporting means, a pivotal mounting for said bracket, a profiling member having a cammed peripheral surface and mounted for movement with said lens supporting means, and an abutment mounted for cooperation with the peripheral surface of said profiling member, whereby as said lens supporting means is rotated, said bracket carrying the same is rocked about the pivot in accordance with the variations in radius of the profiling member, and means forimparting axial movement to the lens supporting means to maintain the peripheral edge of the lens in predetermined positional relationship with the grinding surfaces comprising a cam faced member rockably mounted on the pivot for, and disposed axially and laterally of, said lens supporting means, and means between and frictionally contacting said cam faced member and said lens supporting means and pivotally mounted for movement transversely of that of said cam faced member and-said lens supporting means, said last named means being adapted, upon rocking of said lens supporting means, to impart an axial displacement thereto corresponding to the contouration of theface'of the cam faced member.

6. In an apparatus for grinding optical lenses to form a bevel edge therefor, a pair of grinding Wheels angularly disposed to form by their joint peripheral surfaces 2, v grinding surface, means for rotating said grinding wheels, lens supporting means comprising a pair of co-axially aligned spindles biased toward one another to grip a lens therebetween, means for rotating said lens supporting means, means for pivotally mounting said'lens supporting means, a profiling member having a peripheral cam surface mounted on the lens supporting means and rotatable therewith, an abutment fixedly mounted for cooperation with the peripheral surface of said cammed profiling member, said lens supporting means bein rockable about the pivot therefor, toward and away from the grinding edges of said grinding wheels in accordance with the radius variation of the cammed profiling member, means for effectuating axial movement of the lens supporting means, comprising a cam faced member mounted axially and laterally spaced from one end of said lens supporting means and operatively connected with the pivotal mounting for said lens supporting means, whereby to rock simultaneously therewith, and a cam follower disposed between the one end of said lens supporting means and said cam faced member, said cam follower being displaceable against said end of the lens supporting means in accordance with the contouration of the face of the cam faced member as said cam faced member is rocked to axially and laterally displace the lens supporting means.

'7. An apparatus in accordance with claim 6, wherein means are provided for biasing said lens supporting means into contact with said cam follower and for biasing said cam follower into contact with said cam faced member.

8. An apparatus in accordance with claim 6,

wherein the center of the cam follower is in the same radial plane as the point of grinding contact between the lens carried on the lens supporting means and the grinding wheels, and is set at the same distance from the center of rotation of the lens in the lens supporting means to such point of grinding contact.

9. In an apparatus for grinding optical lenses to form a bevel edge therefor, a pair of grinding wheels angularly disposed to form by their joint peripheral surfaces a V grinding surface, means for rotating said grinding wheels, lens supporting means comprising a pair of co-axially aligned spindles biased toward one another to grip a lens therebetween, means for rotating said lens supporting means, a bracket having bearing sleeves respectively mounting said spindles, means for pivotally mounting said bracket, a profiling member having a peripheral cam surface mounted on the lens supporting means and rotatable therewith, an abutment fixedly mounted for cooperation with the peripheral surface of said cammed profiling member, said bracket and the lens supporting means mounted for rotation thereon being rockable about the pivot therefor, toward and away from the grinding edges of said grinding Wheels in accordance with the radius variation of the cammed profiling member, means for effectuating the axial movement of the bracket and the lens supporting means carried thereon, comprising a cam faced member mounted axially and laterally spaced from one end of said lens supporting means and operatively connected with the mounting for said lens supporting means, whereby to rock simultaneously therewith, and a cam follower disposed between one end of said lens supporting means and said cam faced member, said cam follower being displaceable against said end of the lens supporting means in accordance with the contouration of the face of the cam faced member as said cam faced member is rocked to axially and laterally displace the lens supporting means.

10. An apparatus in accordance with claim 6, wherein means are provided for adjustably mounting the cam follower, whereby its path of REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 250,691 Valiquet Dec. 13, 1881 980,133 Slavin Dec. 27, 1910 1,226,329 Hansen May 15, 1917 1,254,253 Marchant Jan. 22, 1918 1,269,680 Bugbee June 18, 1918 1,489,606 Long Apr. 8, 1924 1,666,746 Maynard Apr. 17, 1928