US2437567A - Lens edge grinder - Google Patents

Description

March 9, 1948. R, c, UHLEMANN LENS EDGE GRINDER Filed JulylO, 1946 4 Sheets-Sheet 1 March 9 1948. v R, C, UHLEMANN 2,437,56?

LENS EDGE GRINDER Filed July l0, 1946 4 Sheets-Sheet 2 |98 INVENTOR.

BY R. COLBERNT UHLEMANN 75H5/ jf ATTORNEYS arch 9, 1948. R, C, UHLEMANN l 2,437,567

LENS EDGE GRINDER Filed July l0, 1945 4 Sheets-.Sheet 5 IN VEN TOR.

Y R. COLBERNT UHLEMA N N 5 Y ATTORNEYS LENS EDGE GRINDER INVENTo R. COLBERNT lUHLEMANN TToRNEYs Patented Mar. 9, 1948 LENS ED GE GRINDER Richard Colbernt Uhlemann, Barrington, Ill., assgnor to Uhlemann Optical Co. of Illinois, Chicago, Ill., a corporation of Delaware Application July 10, 1946, Serial No. 682,684

This invention relates to a machine for grinding the edges of blanks of glass or other grindable material to a predetermined contour. More particularly it has relation to a machine of that type for grinding the edges of optical lenses.

In the manufacture of eyeglasses, great variety in the contour of the finished lenses is encountered, these being circular, oval, pear-shaped, et cetera. After having been ground to prescription upon its faces, the lens is rough-cut to approximate peripheral outline and then ground to the finished contour. Sometimes the edge-grinding is performed before the surface-grinding, the order of these two phases of the operations being immaterial in so far as the subject invention is concerned.

Grinding of the edges of the lens is normally done with the aid of a template, this being usually a dat piece of metal formed on its periphery to a predetermined outline whereby a follower adapted to bear thereagainst may, during joint rotation of the template and glass blank, regulate the position of the blank to the grinding wheel at all positions of such rotation to cut the lens to finished form. Frequently it is desirable, when matching a new lens to replace a broken one of a pair, to use the unbroken lens as the template.

Machines for performing the operations aforesaid are well known, but in so far as my experience has demonstrated, all suier from lack of ease and iiexibility of adjustment, are unduly complicated for the performance of a relatively simple operation, and are incapable of a high rate of production. For example, best practice directs a rough-grinding operation followed by a finish grind, and in present machines transition from one grinding wheel to the other, or the shifting of the blank from one part to the other of a two-part wheel, is slow and cumbersome.

Having in mind the foregoing and other factors, the principal object of my invention is the provision of a machine for edge-grinding, particularly lens edge-grinding, which is compact, possesses few parts, and is capable of simple and rapid adjustment to meet the variety of work entrusted to such machines.

Another' important object is to provide a machine as aforesaid in which the template and blank are supported for joint rotation on a common axis, the latter being oscillatable about a shaft which constitutes the main drive shaft.

A further object is to provide improved means for holding the template whichY is positive and accurate during the grinding operation but is 3 Claims. (Cl. 51-101) f 2 capable of rapid unlocking to release the template and to load a different template.

Still another object is to provide improved means for gripping the blank positively during the grinding operation but which is adapted to be rapidly disengaged for removal of the finished blank and insertion'of the next piece of work.

Another object is to so arrange the parts as to allow an unimpeded working zone to facilitate inspection of the work in progress, and to permit easy access to theA work-holding means.

For lenses having varying transverse dimensions but the same general contour, it is possible to use the same template, but in such cases the position of the follower relatively to the oscillatable work-head must be adjusted. Present machines are impractical in this respect, as the adjusting means is not easily accessible and the adjustment is subject to disturbance during grinding.

Accordingly a further object is to provide simple and easily accessible means for adjusting the position of the template follower, which once set is not capable of slipping out of adjustment.

An additional object resides in the provision of conveniently positioned, rapidly movable means for shifting the blank'from rough-grinding to finish-grinding position..

Another object is to provide a machine as aforesaid in which a single handle is provided for holding the oscillatable head forwardly while loading the blank, and for operating the blank clamping means, thus leaving the other hand free for placing the blank in position and eliminating the necessity of a separate latch for maintaining forward position of the head.

In the drawings, which show one form of carryl ing the invention into effect:

Fig. l is a cross-sectional view taken substantially in a plane passing through the axes of the lens and template spindles and the power shaft;

Fig. 2 is a plan View partly in cross section;

Fig. 3 is a cross-sectional view taken substan-4 in turn carrying the gibs'22---22attachedthereto by screws (not shown). Slidable intermediate the gibs 22--22 is the plate 23 having an ear 24" into which is threadedly engaged the belt-tension adjusting screw 25 accessible exteriorly of the4 Wall I4, and the head of whichfisretainedinH -Ar con'zbined2 electric" motor and speed reducer 21 of a common-typis' shouldered aperture 26.

fastened to the plate 23 by screws (not shown), the output shaft 28 whereof has a gro'ovedpll'ey 29 aflixed thereto. pulley 29, the tension of the belt being regulated by screwl 25Y in an obvious manner. Belt 3 2- extends upwardly through an aperture 3 3 and passes over a-grooved pulleyy 34 to be detailed hereinafter.

Walls I3 and |5 meet in anoiset at'thefront of thev machine to formv sub-walls 31 and38, the latter having pads 39 -39 at the' endsv thereof whereon bearings4 I4 I are mounted. Rotatable in bearings 4|-4| is themainorV power shaft;l 42 retained axially in-one direction by a headI 43 thereof, and'in theiother direction-by' astop'collar 44.v Pulley 34' is' keyed toshaft" 42 by a pin` 45 andl is provided' onitsright-hand face' withan integral cam'surf'ace 46. Oscillationof'the Workcarrying; head,to' be described; is effected byl a sleeve 5| having an' aperture 52 by' means' of which the sleeve and'theparts associated therewith may slideY axially with respectto shaftf4'2. Sleeve 5| has' any integral cam-following' projection 53, and further is united by an arm; 50 and screws' 551:0 an eccentrically-positioned sleeve-54. The' work-carrying head 60 comprisesV a' rigid frameiGI having a" pair of depending arms 62 and 631inciuding apertures 64l and 65A permitting oscillatable and slidable movementl of the head 60` with'respect to'the' shaft 42 as the' template is movedagainst' its` xedfollower and the' head is reciprocated from left to right.' Such horizontal reciprocating movement of the frame 6|,

for mnvingl the blank ba'ck'an'd fortha'cross the r grinding? Wheel, is' effectedl by cam' 46 and follower 53', the movement imparted' to the' latter being transmitted to sleeve 54'which' in tui-nearriesA a'studv 61 including a iiange Iiythe'stud and ange being received in shouldered aperture 69. Stud 61 is threadedly engagedI in' armv 6'3 and' has a' handle 12 pinned'at 1-3 to itsl opposite end;

To afford appropriate contact of the bl'ankwith the grinding v'vhe'el,` and to provide pressure' of the template against its follower, the arm 63 carries an extension 14 attached thereto by screws the lower end 0f the arm having a stud 16 through a hole 11`of which passes one terminal of the tension spring 1 8; the other terminal being correspondingly engaged in the head vof a screw 19 threadedly mating with the central boss 8|| ,of a handle 82.

v The o scillatable head 60 is adapted to carry the lens blank 9| and template 92 for joint rotation and reciprocation withV respect to the periphery of the grinding wheel, the head andits appurtenant parts also oscillating as a WholeY in order that the template may,- byr maintaining contact with a xed follower, cause the blank to A V-belt 32 passeso'vr th'eI 4 be ground to a predetermined contour as controlled by the outline of the template.

Referring particularly to Figs. 1 and 6, the lens blank 9| is gripped between a pair of resilient annular pads 93 and 94, e. g., of rubber, cemented to carrying discs and 96 respectively. The latter are each provided with a pair of diametrica-lly positioned apertures S1`and 98' respectively, snugly to rceivei`pairs` of pins II and |32 affixed to chucks |03 and I 04 respectively. The parts just described are conventional in lens edgegrinding machines, and further amplification is deemed'u'nnecessary.

Chuck IQ4iis'apertured at |05 to t snugly over arpilot |06 integralwith the spindle |01 of the live center |08, the spindle bearing within a sleeve |09, and is provided further with apertures S9 ttingpinsl'in'live center |88. Live center |38 is ofconventional construction and includes thrust ball ||I and retaining screw ||2 therefor. A sleeve ||3 receives the live center |63 with a tapered'pre'ss `t, and a compression spring I|4 retainedf by a'nadjustableknurled head screw I l5 serves to urge sleeve 3 and center |68 to the left. Screw' II'5 isV threadedly engaged in an end plate ||6 fastened by screws ||1 to a housing ||8 formed as; a'n integral part of the frame 6|.

Sleeve I'I3 isY providedfupon the lower portion of its'- periphery with rackteeth |2| engaged by apinion |22 aiie'd to aV shaft |23, the latter be* ing'rota'tab'le in housing ||8`and having a handle |24' (Figs. 2; and 3) securedA thereto.

IChuck- |03 is similar in construction to chuck |04, the' aperturesf|30 thereof 1being adapted to engage corresponding pins I3| in the face of Harige |32 formingv part of the template spindle |33. 'Ihe latter is supported for rotation in bearings |34 set into a housing |35 also forming an integral part of the frame 6|. spind1e las is threaded to receive a nut |36 for endwise retention'o'f' the s'ame',whi1e flange |32 functions correspbnding'ly at the opposite end. An end cap |31 attached by screws |38-locks left-hand bearingA |34 to. housing"v |35. Intermediate the chuck |63'and-'lang`e' |32 is an oil de'ector disc |4| to deect oilor' grease thrown from right-hand bearings |34 awayl from the grinding zone. Cap |31 includes an oil seal |42.

Shaft |33 is reduced in diameter at |43 and is again reduced to provide a pilot |44. A chuck |45 isA adapted to t over portion |43, the chuck carryigr setscrews |46 bearing against steps |41 cut into portion |43 whereby a predetermined accurate'y angular positioning between the chuck and shaft |33 may be set and maintained. Inserted in the lefthand face of chuck |45 is a pair of pins' |48 adapted to mate with apertures |5| in the template 92, a central aperture |52 thereof fitti-ing over pilot |44.

For maintaining template 92 against the chuck I45thereis'a disc |53 having a resilient ring |54 cemented thereto and in contact with the template. Servingtolsupport disc |53 is a chuck |55 including pins' |56 entering apertures in the disc.

In orderl to permit rapid disengagement of a template 92 and engagement of another template, and to provide the pressure necessary to hold the template in operative position, there is an arm 6| slidable in an aperture |62 in housing |35, the arm being axially apertured as at |63 to slide upon a xed stud |64. Stud |64 is secured in the frame 6| by a pin |65, and the head |66 of the studA |64 abuts a compression spring |61 positionedvwithin a recess |68 thus normally to urge arm I 6I inwardly. A pin I 12 projecting in two directions from stud |54 engages diametrically opposed slots` |13 in the wall of the arm ISI, whereby. arm' |.9l is maintained in the angular position shown during the grinding operation, but is free for rotation to clear the template 92 for removal when arm |6| is manually drawn to the left.

The upward extension |15 of arm |6| supports a pilot |15 including two oppositely extending cylindrical portions |11 and |18, the former being pressed tightly into a suitable aperture |19 in extension |15, and the latter fitting freely in an aperture |99 in chuck |55.

For rotating the yblank 9| and template 92, the power shaft 42 is utilized, the same being slotted at |8| to receive slidably .a pin |82 secured through a pinion |83. The pinion |83 is constantly biased to the left by compression spring |84 intermediate pulley 34 and pinion |83, while the pinion is maintained in proper relation with the head 60 by means of bracket |85 secured to the head 6| and the arm 62. Pinion |83 meshes with an idler pinion |86 revoluble on stud |94, and pinion |96 in turn drives a pin -initially x the position of the lens blank with respect to the face of the wheel. Such result could also be obtained by moving the wheel, but such adjustment is not resorted to until the limit of co-operative adjustment between template and follower has been reached and it can no longer accommodate for wearing of the wheel.

The follower mechanism is best shown in Fig. and includes an anvil 9| carried on an integral arm |92, there being a circular aperture |93 and an arcuate slot |94 therein. A bracket |95 includes a forwardly extending bifurcated portion |96 in the space of which the arm |92 is slidably tted. Cap screws |91 extend through portion |96 and the apertures |93 and |94, and by means of which anvil |9| may be rotated through the arc permitted by slot |94 in order to present the face of the anvil most advantageously to the template 92. Bracket |95 includes a dovetail recess 29| adapted to engage slidably a correspondingly formed plate 202 fastened by screws 293 to the top wall I5. A `,downwardly extending arm |98 passes through clearance holes 294 and 205 in the wall |5 and plate 202 respectively, and is secured to bracket |95 by screws 296.

Arm |98 has a, threaded aperture 201 with which a threaded stud 298 is engaged, the forward end of the stud passing through wall |3 and being secured in a handle 209. A stop collar 2|2 retains stud 299 against the wall I3 and per-- mits rotational movement only thereof. Consequently, to eifect forward and backward adjustment of the anvil |9'|, handle 299 is rotated to shift arm |98 and bracket '|95 in the desired direction.

The machine of the instant invention may utilize a cylindrical grinding wheel on the edge of which the work bears, or I may use the sloping face of a frusto-conical wheel. The latter is shown in the drawings (Fig. 2) andcomprises a rough grinding surface A and a nish grinding surface B, the wheel 2 0 being supported on the usual spindle 2|| supported rotatably in suitable bearings. AThe latter are supported in a quill 200 carried by a bracket 2 I3 extending from the base block 2|4. If desired, the block may be adjustable angularly with respect to the frame of the machine in order that the faces A and B may be aligned accurately with the axis of the work, and may be adjustable transversely to accommodate for wear of the wheel. An electric motor 2|5 drives a. lbelt 2|6 which passes over a pulley 2|1 keyed to the spindle 2| I;

In order to protect the workerv from the spray and splash of the wet grinding operation, the frame 6| is provided with side wings 22| and 222 intermediate which is the arcuate transparent hinged guard 223 (Fig. 4) having a handle 224 for raising and lowering the same. Guard 223 is preferably of a transparent plastic material A fixed rear guard 225 al-so supported on the frame 6| co-operates with guard 223 and has a slotted aperture 226 to clear the spindle 2| To furnish water to the grinding area, a nozzle 23| is provided, the fluid being pumped from a suitable reservoir in the base of the machine through conduit 232 and the ow whereof is controllable through valve 233. The pump may be driven by motor 21.

Assuming the lens 9| shown has been ground, and that template 92 has served its purpose, the handle |24 is grasped to swing the head 69 about the shaft 42 against the tension of the spring 18. Meanwhile the left hand holds the finished lens 9|, so that Without removing his right hand from handle |24, the same may be rocked clock- Wise to cause pinion |22 to operate the spindle |01 to the right. Thus pad 94 is released from the lens and it may be removed to the usual workholding tray. Now with the left hand free, the operator may grasp the arm |6| by hooking his ngers around extension |15 to withdraw the arm to the left against pressure of the spring |61, whereupon the arm may be rotated to clear the template 92, the freed arm then resting with its inne end face against pin |12. Accordingly the left hand is now free to remove the template from pins |49 and to insert the template required for the next lens to be ground. Arm |6| is then released from locked position and restored to the position shown in' Fig. 1 to grip the template. Following this the next blank lens is inserted between the pads 93 and 94, handle |24 is released to clamp the blank, and the head 59 is restored to normal, i. e., grinding, position.

In the event the template 92 .just inserted is of the correct contour brut not of the transverse dimensions required 'by the new blank 9|, it is necessary to adjust the position of the blank relatively to the face of the grinding wheel by movement of anvil !9|. Rotation of handle 209 will effect such adjustment in the manner already described. Such adjustment is generally predeterminable by the operator, and is preferably made before the blank 9| is brought against the wheel 2| 0.

In Fig. 1 the head 5| is shown in position for rou-gh grinding, i. e.. to the right. To locate the blank 9| in proper position for finish grinding, i. e., relatively to face B, the handle 12 is turned to move stud 61 in its threaded aperture and to force the head E9 to the left, the spring |84 urging thesame and moreover maintaining proper yielding engagement of. the follower 53 with cam 46. Shifting of the blank from roughto finish-grinding.iseffect'ed withoutstoppingthe machine, or making any adjustments. other'. than rotatingthe handle. T2'.

Ihasmuch as stud 67?,.-flange 6.8' thereof; and the. threaded. engagement of the stud. with arm 63'of the head. 6D' renders the sleeve, 5| unitary with the head,.rotation. of cam.46 willoscillate the head' laterally of theimachine to reciprocate the blank across the face A or face B as required for uniform wear ofthe wheel faces and cleanliness of the. finished, edge ofk the, lens.

To facilitate loading of the blank between the pads 93 and 94, any, ofthe well-known work,- holders may be. use.d. In one such holder the optical center ofthe lens is located in` a true axial position with respect to and between the discs 95 and 96 and the latter with the. lens clamped therebetween are transferred to the chucks |113 and |114'. In thatway the optical center ofthe lenslies on theaxis of the. spindles |01 and |33.. Rapid and. accurate positioning of the templatev 92 with respectl` to the said. axis is effected by registration thereof with the, pilot |.44 and pins |48, the.latter preserving angular positioning of the. template. with respect. to the. lens blank, and the pilot |44' taking the pressure againstithe template dueto spring 18.

The machine of. my inventionis. flexible to a degree not found in prior equipment, especially in so. far as the template gripping, arrangement is concerned'. As heretofore pointed out, either a standard flatmetal template as. shown in, Fig. 1 may be used or, in those. cases where. no. such template 'of the` proper contour is available. and it is desired to match a broken lens, thealternative construction shown. in Fig. 6. is employed.

B'y. comparing. that figure with Fig., 1 it is. to be noted that aK ring 236 adapted to t. over pilot |44 andhaving a resilient pad-231, together with the disc L53 heretofore described., is. utilized, the disc 236 having a pair of apertures engaging pins |48. Accordingly the. mate 238. to the broken lens ispreliminarily setup with disc 53-. and. ring 236 in a work-holder as described.. andthe assembly transferred intermediate the. chucks |45 and |55.

In contrast toflens. edge grinders now available utilizing. cylindrical. grinding. wheels of con-ventional material,A e. g., whetstone.. silicon carbide, or alundum, I, prefer awheelv comprising diamond particles and silicon.- carbide or any so-called diamond grinding wheel. It has been found that the speed of. grinding increases approximately threefold, the wheel is eiective for longer periods between re-dressings, and. a much lighter motor may be used due to the. smaller size of the diamond wheels..

One of the outstanding advantages of my ma.- chine resides in the. simple means for. transferring the work from the roughto. the finish-grinding siu'face of the wheel. Prior devices required a rather bothersome manipulationo setscrews. with respect to the oscillating cam, the adjustment being made, twice for each. blank ground. However, my machine is. almost instantaneously and positively settable by handle '12, the. movement of arm 63 being limited intermediate cam 53 and the arm. 50.

An-other means for holding the metal template 92 is shown in Fig. 8, in which form the. swinging arm |6| is not utilized, and, the end of the spindle |43 is provided with an integral axial pilot 240 of Phosphor bronze or other resilient material diametrically slotted as. shown, whereby the same may be sprung slightly to grip the standard central opening in the template, and

l a pair of pins 24| is alsopiovidedto engagetlie standard` locating holes offl the template. While the means of Eig8 affords a more rapid. change from onetemplate toanothenthe preferredv embodiment employingvthearm |6| is.more positive.

While I haveshown particular embodiments of my invention, it will be understood, of course. that.V I do not wish to. be, limited thereto since many modifications may be made, and.I there.- fore contemplateby thev appendedclaims to cover any such modifications asf fall. within the. true spirit and' scope 0f my invention.

Having thus described'j my invention., what I claimand desire to secure by Letterslatentisc.

1. A grinding machine o f theV class. described comprising a trama, a power shaft rotatably mounted' in.said;framea head1 angularly oscillatable andreciprocably slidable, on saidfshaftarst spindlerotatably mounted omsaid head and having an axis parallelttdsaidpower shaft.,a second spindle coaxial. with said' rst, spindle and, rotatabl'e therewith, a chuck4 at one end of said first.spindlea chuck at the adjacent end of. said second spindle, said chucks including resilient means for gripping the. work therebetween,` said second spindle being,freelyrotatable in. said head, said first spindlebeing driven! by said power shaft, there being, transmission means between said iirst spindle and. power. shafts. a chuck at the oDDO- site end of. saidl rst, spindlcfor holding a template, an arm. slidably mounted with respect to said head.. saida arm including. a chuck, adapted to. engage, one, face ot said template,` and resilient means, associated with-saidarm., for applying engaging, pressure toisaid. template, said. arm and head' havingd mutually cngageable means for maintaining a, predetermined. position of the chuck thereon with respect to, said template,` said means being di'sengageable manually for; removingl said template, from the. machine.,

2. In a, grinding machine oi theclass4 described having an oscillatable, andswingablework-carrying. head, a power. shaft., a., cam rotatable therewith,l a sleeve axially slid'able on saidl shaft, a cam follower carried by said sleeve. a pair of spaced-apart anges integral Withsaid sleeve, an arm integralV withsaid sleeve and, extending; radially therefrom, a bracket. carried. by the. head and having two opposed faces. and an aperture engageable over said sleeve. and, manualmeans interconnecting said arm and bracket for` shifting said head'. relatively to said sleeve for varying the lateral position of the, work.

3. In a. grinding machine, of the class described having an oscillatable. work-carrying head for traversing the work across. theface, of the grinding wheel, a., power-driven rotatable shaft carrying a cam., a member axially slidable relatively to saidshaft, said member including a cam follower portion, and screw-threaded means adi-ustablyf se* curing said member to said head for shifting said member relatively to said head whereby to alter the range of movement of the workrelatively to the face. of the wheel.

RICHARD. COLBERNT UHLEMANN.

REFERENCES CITED.

The following references are of record' in the le of this patent:

UNITED STATES PATENTS Number Name 1 Date 615,089 Murdock Nov. 29., 1898 670,500 Morgan et al Mar. 26, 1901 (Other references on following page) Number 10 Name Date Schultz Feb. 21, 1928 Maynard Mar. 13, 1928 Rakel May 21, 1929 Shiiman Feb. 12, 1935 Tandy Jan. 17, 1939 Campos, 3d July 11, 1939 Grasser Dec. 19, 1939 Maynard June 17, 1941 Wilhelm Aug, 29, 1944

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