US2621418A - Lens axis aligning device - Google Patents

Description

Dec. 16, 1952 W, J, sCHMlDT 2,621,418

LENS AXIS ALIGNING DEVICE Filed April 23, 1948 IZ I4 3| Il l0 1N VEN TOR. @4mm WiLLi/AM d. SCHMIDT l 1 n mzg BY 26 J 621%, W

ATTORNEY Patented Dec. 16, 1952 UNITED STATES PATENT OFFICE LENS AXIS ALIGNING DEVICE William J. Schmidt, Independence, Mo., assignor to American Optical Company, Southbridge, Mass., a voluntary association of Massachusetts Application April 23, 1948, Serial No. 22,913

10 Claims. 1

This invention relates to lens axis aligning devices and has particularly reference to an improved device for accurately locating a lens blank in proper axial position in an abrading fixture.

One of the principal objects of this invention is to provide means for axially aligning an ophthalmic lens blank with respect to the axis of a fixture used for supporting said blank in proper axial position during a subsequent surfacing operation.

Another object is the provision of means in a device of the above character which will indicate the condition of wear of the axis retaining parts of the xture in which the lens blank is axially supported.

Another object is the provision of a device of the above character which is simple in construction and which permits the axis of an ophthalmic lens blank, while carried by lens holding means, to be quickly, eiiiciently and positively aligned with respect to the axis of a fixture used for supporting the blank and holder in proper axial position during a subsequent surfacing operation.

With these and other objects in View, the present invention will be more clearly understood and the advantages thereof fully realized from the following description read in conjunction with the accompanying drawing in which:

lig` 1 is a front elevational view of a device embodying the invention;

Fig. 2 is a top plan view of the invention;

Fig. 3 is a fragmentary sectional view taken on line 3 3 of Fig. 2;

Fig. 4 is a sectional view taken on line 4 4 of Fig. 1;

Fig. 5 is a fragmentary top plan View of a lens blank and a lens supporting bridle, illustrating particularly the method of performing the axis aligning operation; and

Fig- 6 is a sectional view showing a modiiication of the means for retaining the axis aligning wire in position.

In the manufacture of articles such as ophthalmic lenses, in many instances it is essential that the lenses be provided with surface curvatures in designated meridians exactly as described. Therefore, when a lens blank has been marked with an axis line or lines and blocked according to the customary practice in the Inanufacture of such articles, it is essential that the lens blankv be aligned in a surfacing machine on an axis coincident 'with the axis on which -the-blankwas' blocked;V That it, when a lens blank is blocked, it is? positioned with respect to its cylinder axis V@asV well'v as yotherfactorsof the iinished'prescriptive -power which `the resultant lens is'to possess and is xedly attached to and retained by a block while in that position. Since a blocked lens blank must be surfaced -in accordancek with the position of the'blank` as chine with its axis exactly as positioned during the blocking operation.

Heretofore, it has been'the general practice to insert a lens'blank in a surfacing machineby merely relying upon the operators eyesight to align the blank in the bridle so that when the bridle is inserted in.` a surfacing machine ysuch as a cylinder grinder the blank will be axially 'aligned in the machine on the axis on which' it was blocked, and subsequently surfaced. Howeverfby relying 'only on'the human element for accurate alignment, many-inaccuracies resulted since a careless or inexperienced operator or an operator having defective vision might improperly positionthe blank with respect to its axis and, consequently, blanks may be inaccurately surfaced. In addition to this detrimental feature, it is possible that worn bridles might beused for supporting a lens blank to be'surfacedpthe worn bridle also 'causing the lens blank to be surfaced inaccurately. These objections are overcome by the present invention wherein there is provided an aligning -devicevseparate and-'independent 'of blocking or grinding machines.

Referring morefparticularly to the Vdrawing wherein like characters of referenceidesignate like parts throughout theseveral views,'the device embodying the invention comprises an aligning device I0 which' may Ibe xedly ksecured to a bench or other suitable supporting means'l I, such `asby screws I2 which are adapted toV extend through an extension `I3 formed integral with each end of the device. The device is provided with a pair of spaced abutments such as .uprights I4 and I5 joined by a web portion I6, each upright I4 and I5 beingprovided with a projection or boss I'I and I8 respectively. The bos-ses I'I and lI3 lare located on the 'front surfaces of the uprights near the upper ends thereof and .t-he. boss I'Iypartially into the. boss. .The boss I8 is provided with a shallow bore 22 which bore is axially aligned with the base of the kerf and adapted to extend only partially into the outer end of the boss I8.

A plug 23 of such a lsize las to snugly lreside within the bore 22 has a longitudinal bore therethrough into which is projected one end of an axis aligning member 24, which member may be made of any suitable finely drawn material such as piano wire or the like, a set screw being provided in a transverse threaded opening in the plug 23 to be brought into abutment with the member 24 and by Wedging action to thereby firmly retain the member 24 in position within the plug.

A threaded stud 26 is adapted to slidably reside in the bore 2| of boss |1 andY provided with a longitudinal slot 21 in the bottom of which is adapted to 4reside the other end of the aligning member 24. A set screw 28 is also provided in the head of the stud 26 to secure the member 24 in the slot 21 in a manner similar to the set screw 25.

Upon locating the ends of the member Within the bore in the plug 23 and in the slot 21 of the stud 26. and adjusting the set screws 25 and 23 to restrain the member 24 from displacement, the stud 2E and plug 23 may then be inserted within the bores 2| and 22 respectively with the aligning member 24 being adapted to extend from the stud 26 to the plug 23 in spanning relation between the bosses and I8 and uprights I4 and I5 and to reside within the kerfs I9 and 2|) in the bosses I1 and I8. To counteract slack in the member 24, adjusting nuts 29 and 30 are provided on the stud 26 adjacent the outer end of the boss I1 so that by tightening the nut 29 against the boss I1, the stud 25 will be drawn in the direction outwardly of the bore 2 I, thereby taking up the slack in the member 24, the nut 30 then being adapted to be tightened against the nut 29 to lock the parts in position and thus prevent the member 24 from becoming slack until the lock nut 30 is released.

A lens blank 3| to be surfaced is attached to a lens block 32 by suitable blocking means and is marked by one or more lines 33 indicating the predetermined cylinder axis of the lens blank. The lens block 32 is adapted to be positioned on -a bridle 34, the bridle constituting a well known but important part of a toric or cylinder grinding machine such as may be used for performing the surfacing operation on the lens blank. The bridle 34 includes a substantially disk shaped holder 35 provided with a vertical circular opening di'soosedcentrally thereof. The lens block 32 is adapted to be'positioned'upon the upperV surface of the holder 35 and h'asits undersurface provided with a circular extension 35 adapted to rotatably reside within the vertical opening in 'the holder'35 and to be locked immovable therein by means of a set` screw 31.

The h'older`35 is provided with a pair of diametrically opposed arms 38 threadedly or otherwise connected thereto, the arms 38 being provided on eachV side thereof with engagement portions such as longitudinal llers 39, the arms and fillers being accurately' made and assembled so that the edges of the fillers are adapted to be positioned on a plane parallel with 1an axis Y through the center of the bridle 34. This feature is clearly illustrated in Fig. 'wherein the aligning member or'wire 24 is indicative of the center line through the holder 35 and arms 38,

"and'it can beY seen that the'edges of the fillers ber 24.

4. 39 are parallel to this line throughout their entire lengths.

The uprights I4 and I5 `are each provided with engagement or abutment portions having planar `frontal surfaces 40, these surfaces being accurately machined parallel with the aligning member 24, the member 24 being disposed a distance to the front of the surfaces 4|) equal to the distance between the edges of the ii-ller 39 and the center line of the bridle 34. This is clearly illustrated in Fig. 4 wherein it can be seen that the -centers of the bridle arms 33 and the aligning member 24 are equidistant from the surfaces 43 on a common center line 4| drawn vertically through the bridle arms and the aligning member.

In performing an aligning operati-on, a lens blank 3| which has been previously attached to a. lens block 32 and provided with axis lines 33 is placed upon the holders 35 with the extension 3S being movably disposed in the opening in the holder. Then, as illustrated in Figs. 1 and 2, the bridle 34 is placed by the operator against the uprights I4 and I5 and in spanning relation thereto with the edges of the llers 39 in one side of the arms 38 being positioned against the machined surfaces 4B of the uprights and with the lens blank 3| positioned between the uprights and immediately below the aligning mem- To align the blank 3| with the center of the bridle, the blank 3| is rotated until the axis lines 33 are disposed in alignment with the member 24. The set screw 31 is then tightened to prevent the blank from further rotation, and the bridle and lens blank may be then removed from the device and inserted in a surfacing machine.

By this means, the lens blank is assured of accurate alignment with respect to the bridle so that upon insertion of a bridle and lens blank in a surfacing machine, the axis is definitely and accurately established and retained as determined by the previous blocking operation, and inaccuracies resulting from poor axial alignment are thus eliminated.

It is important that the dimensions between the center line of the bridle and outer edges of the iillers 39 be maintained. By this means the condition of the fillers may be checked since if it is found impossible to axially align a lens blank in the device this will indicate, if the lens blank has been accurately marked, that the llers are worn and should be replaced.

It is conceivable that other means may be used to retain one end of the aligning member 24 such as the means illustrated in Fig. 6 wherein the opening 2| in the boss I1 is threaded to threadedly receive the stud 23, with a single lock nut 42 being used to retain the parts of the unit in place.

From the foregoing, it Will be understood that the present invention overcomes many undesirable features of prior methods for axially aligning lens blanks with otherrdevices by providing simple and eiiicient means for obtaining true alignment 'thereof by eliminating much of the human element, and further improving upon the prior art by providing such a device which will also indicate the worn condition of Vparts used therein, thus providing greater eiliciency and more accuracy in such operations.

While certain novel'ieatures of the invention have been shown and described and are pointed out inthe annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the device'illustrated i :and in its :operation may-.be made: by:those skilled in the art without departing."fromlithe'spirit of rthe invention.

I claim: 1. `In a device of the character described, a .device for. axially aligning: a lens blank comu prising a support having spaceduprightszformed 1 thereon, said uprights-having abutment portions with aligned vertically dispose-d planar frontal surfaces, longitudinally disposed bosses .formed on said uprights above said portions lhaving the :said planar surfaces 'and extending forwardly thereof, an elongated aligning member having its "ends adjustably supported by said bosses and dis- Aposed at a distance forward of and parallel to the said planar surfacesfand a .bridle adapted 'f to carry' the llens blankrto :be aligned 'comprising f aiholder having al '.vertic'al centrally Adisposed 'openingthereinand having a pair of .arms connected in diametrically opposed relation thereto, k'said arms having longitudinal-engagement portions disposed in'aligned relation, a lens`block to which saidv lens blank-may be connected provided with an extension adapted to `rotatably reside in the opening in said holder, said bridle being adapted to be positioned against the uprights with said engagement portions in'abutment with the planar surfaces of said uprights and with the lens blank positioned betweenthe uprights and below said aligning member whereby the blank can be axially adjusted on the holder to bring the lens blank into axial alignment-with the aligning member.

2. In a device of the character described; a device for axially aligning a lens blank having axis lines marked thereon comprising a support having spaced uprights formed thereon, said uprights having abutment portions with substantially vertically disposed planar frontal surfaces aligned in substantially the same plane, longi-x ditudinally disposed bosses formed on said uprights above said abutment portions having said planar surfaces and extending forwardly thereof,

an elongated aligning memberA having its end adjustably supported by said bosses and disposed at a predetermined distance forward "of and parallel tothe said planar surfaces, and a bridle adapted toadjustably carry'the lens blank to be aligned comprising a holder having al vertical centrally disposed opening therein and having a pair of arms connected in diametrically opposed relation thereto and having their longitudinal axes aligned with the axis of said holder, said arms having disposed thereon longitudinal engagement llers of such size that the distance between the outer edges of said fillers and the longitudinal axis of said arms is in correspondence to the distance at which the aligning member is disposed forwardly of the planar surfaces of the uprights, a lens block to which said lens blank is connected, said lens block being adapted to be adjustably positioned on said holder and provided with an extension adapted to rotatably reside in the opening in said holder, said bridle being adapted to be positioned against the uprights with said engagement fillers in abutment with the plane surfaces of said uprights and with the lens blank positioned between the uprights and adjacent said aligning member whereby the blank can be adjusted on the holder to bring the longitudinal axis lines thereon into alignment with the aligning member.

3. An aligning device of the character described comprising a pair of spaced abutment portions joined by an integral web, said abutment portions ill 6 having `on their same side i `engagement portions lying substantially in ithe samefcontinuous plane and vhaving an -open area therebetweemand supports located to one side'of and extending forwardly Vof :the plane of said engagement-portions,

van aligning Awire having its opposed ends secured tosaid supports and spanningthe open area between said engagement portionsgsaid wire being disposed at a predetermined distance forwardly of and extending in a direction substantially parallel with respect to the plane in which-said engagement portions lie.

' 4. An aligningdevice'of the'charaoter described comprising a pair of spaced abutment portions joined by an integral web, said abutment portions having planar frontal surfaces alignedto -lie substantially inthe same vertical plane and having an intermediate open area therebetween, 'and supports located abovesaid abutment portionsand extendingforwardly of said surfaces-an aligning member -secured to said supports 'and' -spanning the open area therebetween, said aligning-member being disposed at a predetermined distance 'aligned Vwith respect to each other to lie` in the same vertical plane, supporting portions located `above said engagement yportions and projecting from said uprights and having -aligned openings therein spaced equidistantly from and on the same side ofthe base as theplane in which said aligned engagement portionsv lie, ay finealigning wire having its ends secured in said openings in the supporting vportions and spanning the open area between said engagement portions, said wire being disposed at a predetermined distance from and extending in substantially Aparallel relation to said plane in which the engagement portions are aligned, and locking means seated withinsaid openings in the supporting portions for maintaining said wire taut.

6. An aligning device of the character described comprising a base'having a pair offspaced uprights joined by an integral web and each having a planar surface on the front side thereof, said planar surfaces being aligned with respect to each other to lie in the same vertical plane and being separated by an open area therebetween, supporting portions located above at least a portion of said planar surfaces and projecting from said uprights, said supporting portions having aligned openings therein spaced equidistantly from and on the same side of the base as the plane in which said aligned planar surfaces lie, a relatively fine aligning wire having its ends mounted in the openings in each of the respective supporting portions and spanning the open area between said planar surfaces, said wire being disposed at a predetermined distance from and extending in spaced substantially parallel relation to said plane in which the said surfaces are aligned, and locking means seated within said openings in the supporting portions for maintaining said aligning Awire in taut assembled relation therewith.

7. A device for axially aligning a lens blank having axis marks thereon comprising a pair of spaced abutment portions lying in substantially the same plane and separated by an open area, a lens blank holder adapted to extend within said o'pen area and having' a pair of diametrically opposed arms, said arms having engagement portions disposed in substantially the same plane and to engage said abutment portions, an aligning member mounted to one side of said engagement portions and located at a predetermined distance forwardly of and in substantially parallel relation with the plane in which said abutment portions lie and substantially coincident with the longitudinal axis of said arms of the holder, and said Y holder having means for rotatably supporting the lens blank thereon, whereby said lens blank may be rotated to cause said axis marks thereon to be brought into coincidence with the aligning member.

8. A device for axially aligning alens blank having axis marks thereon comprising a pair of l spaced planar surfaces lying in substantially the same plane and separated by an open area, a lens blank holder adapted to extend Within said open area and having a pair of diametrically opposed arms, said arms having engagement portions with surfaces disposed in substantially the same plane and to engage said planar surfaces, an aligning member mounted to one side of the portion of said planar surfaces to be engaged by said arms and inra predetermined spaced substantially parallel relation with the plane in which said planar sur- Y faces lie and substantially coincident with the spaced planar surfaces lying in substantially the same plane and separated by an open area, a lens blank holder adapted to extend within said open area and having a pair of diametrically opposed arms, said arms each having an engagejment portion With a surface along its length disposed in substantially the same plane and to engage said planar surfaces, an aligning member mounted to one side of the portions of said planar surfaces to be engaged by said arms of the holder and in substantially parallel spaced relation with the plane in which said surfaces lie and substantially coinciding with the longitudinal axis of said arms, and said holder having a centrally disposed opening for rotatably supporting a lens block having a lens blank secured thereon, whereby said lens block may be rotated to cause said axis marks on the lens blank to be brought into coincidence with the aligning member, and locking means for rendering said lens block immovable.

10. A device for axially aligning a lens blank comprising a support having spaced uprights provided with abutment portions having aligned planar frontal vertical surfaces, an' aligning member' supported above said abutment portions having planar surfaces and at a distance spaced from and substantially parallel to said planar surfaces, and a holder having a pair of diametrically opposed laterally extending arms and an adjustable central portion for supporting the lens blank, said laterally extending arms each having a portion provided with a longitudinal engagement surface disposed in aligned relation, and said arms of the holder being adapted to be positioned against said abutment portions of the uprights with said engagement surface in abutment with the planar surfaces of said portions of the uprights and with the lens blank positioned between the uprights and adjacent said aligning member whereby the blank may be adjusted on said central portion of the holder to bring the lens blank into axial alignment with the aligning member.

WILLIAM J. SCHMIDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 683,115 Gilliom Sept. 24, 1901 1,241,611 Drake Oct. 2, 1917 1,356,656 Pearson Oct. 26, 1920 1,408,339 Bugbee Feb. 28, 1922 1,931,477 Allen Oct. 24, 1933 2,215,663 Frisk Sept. 24, 1940 2,286,669 Carr June 16, 1942

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