U119 tat [151 3,655,276 Wilkinson [4 1 Apr. 11, 1972 s41 OPHTHALMIC REFRACTING CHART 3,294,473 12/1966 Haugen ..351/30 PROJECTOR 3,341,275 9/1967 Haugen ..351/30 [72] Inventor: Leonard A. Wilkinson, Snyder, N,Y. FOREIGN PATENTS OR APPLICATIONS [73] Assignee: American Optical Corporation, 856,897 4/1940 France ..350/204 Southbridge, Mass.

OTHER PUBLICATIONS [22] Filed: Oct. 31, 1969 The Optician, Vol. 153, No. 3959, Feb. 17, 1967, pps. 157- [21] App1.No.: 873,022 162 Primary Examiner-David Schonberg 1211 Ii'ftiiiiiiiijiiiiii: "1x51151 55 3213519783 9 19 Sacher 58 Field 61 Search ..351/30, 31; 350/204 {$13 wmmm Neakm and Robe" [56] References Cited 5 ABSTRACT UNITED STATES PATENTS An ophthalmic refracting chart projector with rotary slide 2,244,687 6/1941 Goldsmith 61281 ..350/204 x 55g;,gjfgg gjgggfifi jfif ,223,521,? jfggf'jfg gggg 2,947,215 8/1960 Mitchell ..350/204x h rt 1 b t d th b h t l 1,698,013 1/1929 De Zeng ..351/30 C a smayaso e elraxes ysuc Como 2,887,006 5/1959 Yale ..351/30 X 1 Claim, 9 Drawing Figures PATENTEUAPRHIQYZ 3,655,276

I sum 1 0F 5 INVENTOR. LEONARD A. WILKINSON my w ATTORNEY PATENTEDAPR 1 1 I972 3,655,276

SHEET 2 OF 5 W 4| 64 u r! FIG. 2

INVENTOR. LEONARD A.WlLK|NSON ATTORNEY PATENTEDAFR 11 m2 SHEET 3 BF 5 8 mm EK VL m A D.

ATTORNEY PATENTEDAPR 111972 r 3,655,276

SHEET h [1F 5 PIC-3.8

FIG. 7

FIG. 6

EN LEONARD A. W KIN N BY XM w ATTORNEY PATENTEDAPR 11 m2 SHEET 5 OF 5 JOEPZOO mJmaFmom INVENTOR. LEONARD A. WILKINSON ATTORNEY xOm . x ii u w E n fi N wi NFL/ 97 E NNMLJQ OPHTHALMIC REFRACTING CHART PROJECTOR BACKGROUND OF THE INVENTION The present invention is related to projectors for ophthalmic refracting charts.

In the field of ophthalmic refraction, it has been known for some time that the use of projectors incorporating certain charts and slides is an improvement over the old wall charts. Typical prior art projectors include a plurality of slides or targets disposed in a linear relationship and moved back and forth or up and down relative to the light path so as to be selectively projected on a screen. In such apparatus, the placement of the desired slide in the projector light path is accomplished manually.

It is an object of the present invention to provide an ophthalmic refracting chart projector having slides mounted peripherally around rotatable discs which are operated by remote control.

Another object is to provide such a projector having controls to permit selective retrieval of the slides contained therein, and allow the practitioner to present slides to the patient in a sequence, particularly preferred by him.

Whereas this sort of sequence is followed by the practitioner for a majority of his patients, it is desirable and provided for in this instrument, that it will reset to the start of the sequence automatically at the end of each refraction when the practitioner turns the projector off.

Other objects, advantages and features of the present invention will become apparent from the following description of one embodiment thereof when taken in connection with the accompanying drawing.

SUMMARY OF THE INVENTION Briefly, the present invention is practiced in one form by an ophthalmic refracting chart projector in which slides are mounted peripherally around discs mounted rotatably relative to the projector light path. By remote control, the discs are rotatable either continuously or in desired increments to selectively place desired slides in the projector light path. Astigmatic and paraboline slides or charts are also mounted peripherally on a rotatable disc and are themselves rotatable relative to the disc by such control.

DRAWING In the drawing:

FIG. 1 is a side sectional view of part of a refracting chart projector according to the present invention;

FIG. 2 is a top view of the apparatus shown in FIG. 1;

FIGS. 3 and 4 are end and side views respectively of a part of the apparatus shown and indicated in FIG. 1;

FIGS. 5 and 6 are end and side views respectively of another part of the apparatus shown and indicated in FIG. 1;

FIGS. 7 and 8 are end and side views respectively of another part of the apparatus shown and indicated in FIG. 1; and

FIG. 9 is an electrical diagram representing the control circuit for the projector apparatus of the present invention.

Referring now to FIG. 1, there is shown a part of a refracting chart projector, generally represented at 2. It includes a lamp 4 disposed relative to a lens system 6 to provide a light path or optical axis 7. A frame, generally indicated by various members 8, supports the structure of this projector apparatus including a rotatable shaft 10.

Rotatable shaft 10 has mounted rotatably relative thereto a first slide-carrying disc 12 and a third slide-carrying disc 16. Shaft 10 further has fixed thereto for rotation therewith a second slide-carrying disc 14. Each of these slide discs 12, 14 and 16 is more clearly shown by individual views in FIGS. 3 through 8.

Referring now to FIGS. 3 and 4, there is shown the first slide disc 12 which includes a cylindrical bearing member 18 and a disc plate portion 20 integral therewith. Plate 20 defines a plurality of apertures 22 disposed around its periphery for the accommodation of slides. There are, set into several of these apertures, as desired, rotatable cells 23 containing certain slides or charts such as a paraboline chart shown at 24 and an astigmatic or sun burst" chart shown at 26. Cells 23 are rotatably mounted within apertures 22 and each has a spur gear 28 integral and concentric therewith. The paraboline chart 24 is rotatable in its entirely while only the pointer rotates relative to a stationary astigmatic chart 26. Disc plate 20 serves as a mounting plate for a gear train including gears 30 and 32, gear 30 being in mesh with gear 28. Gear 32 meshes with gear 30 and further with a spur gear 34 which is rotatably disposed about and concentric with shaft bearing 18. Gears 30 and 32 are mounted relative to plate 20 by suitable fasteners as shown at 36. Spur gear 34 is integral with a hearing member 38, which is rotatable about bearing 18, and which in turn is integral with another gear which is axially displaced and concentric with gear 34. Thus gear 40, operating through gear 34, rotates gears 32 and 30 and ultimately gears 28 to rotate the cells 23 to vary the axis of chart 24 and the pointer relative to chart 26, to keep pointer in line with vertical axis of paraboline chart, i.e. pointer and paraboline slide indicate the same angular displacement when shown to the patient. A gear 42, similar to gear 40 and coaxial therewith, is mounted integral with bearing 18 so as to be rotatable with bearing 18 and plate 20.

Referring now to FIGS. 5 and 6, the second slide disc 14 is shown. Disc 14 is positively fastened to shaft 10 by means of a pin 44 so as to be rotatable therewith. Slide disc 14 defines a plurality of slide apertures disposed around its periphery as exemplified at 46.

Referring now to FIGS. 7 and 8, the third slide disc 16 is shown in detail. Disc 16 includes an integral shaft bearing 48 which in turn is integral with a gear 50, the gear 50 and bearing 48 being coaxial with disc 16 and rotatable about shaft 10. Disc 16 also defines a plurality of slide apertures 52 disposed around its periphery. A spring clip 54 is suitably fastened to disc plate 16 and provides a biasing force against plate 16 so as to hold slides which are inserted over the apertures 52 to the plate 16. An example of such a slide is shown at 56. A similar spring clip may be included on any of the other disc plates 12 and 14.

Referring now back to FIGS. 1 and 2, showing discs l2, l4 and 16 in their relative positions, it will be more clearly seen that discs 12 and 16 are rotatable relative to shaft 10 and that disc 14 is fastened to shaft 10. A gear 58 is also fastened to shaft 10. A plurality of motors 60, 62, 64, 66 are mounted relative to frame 8 as shown in FIG. 2. These motors have respectively mounted thereto pinions 41, 43, 5 I, 59. Pinion 41 is disposed in driving relationship to gear 40. Pinion 43 is in driving relationship to gear 42. Pinion 51 is in driving relationship to gear 50. Pinion 59 is in driving relationship with gear 58. That is, motor 60 controls, through gear 40, the rotation of cells 23. Motor 62 through gear 42 drives disc 12 on shaft 10. Motor 64 through gear 50 drives disc 16 on shaft 10. And motor 66 through gear 58 drives shaft 10 and disc 14.

In FIGS. 3, 5 and 7, it will be seen that discs 12, 14 and 16 respectively have notched cam surfaces around their peripheries. Referring now to FIG. 9, the significance of these cam surfaces becomes apparent. There is biased against each of these peripheral disc surfaces a pair of cam operated switches 68. Switches 68 are fixedly mounted on frame 8. When cam follower 62 of each of these switches 68 is depressed, that is to say within one of the recesses on the cam surface, the associated switch 68 is open, breaking the circuit and interrupting current to the corresponding motor. Thus, each of the recesses in the peripheral cam surfaces represents a stop position for the associated motor and the disc itself.

Discs 12 and 16 each have projecting therefrom a switch actuator lug 75. These lugs are operatively disposed relative to one only of the two limit switches 68 corresponding to its respective disc. For the same purpose, disc 14 has on its periphery a relatively large cam recess 76 in operative relation to an oversize follower 71 of one only of the limit switches 68 associated with disc 14. The purpose of these lugs 75 and the recess 76 is to actuate at a single position of the disc a motorstop switch 68, by opening such switch. Recess 76 performs the same function as lugs 75, the reason for its presence on disc 14 is space limitations. The oversize recess 76 and its associated follower 71 prevent follower 71 from moving to a shut off position at any of the other cam recesses around disc 14. When switch 74 is in the off position, discs 12, 14 and 16 return to predetermined base or normal position.

There is also in association with each motor a manual normally open switch 72 which, when held closed, permits continuous operation of its associated motor. When a switch 72 is only momentarily closed and then opened, however, the associated motor will continue to operate only until the corresponding disc member reaches the next cam recess into which follower 70 falls opening the motor circuit. Thus, each switch 72 can be held closed for continuous operation or it can be simply momentarily closed for starting the associated motor with the motor being stopped automatically at a desired spot by the cam switch 68. This optional manual or automatic operation applies to motors 62, 64 and 66. Motor 60 which rotates the axis of cells 23 is shown here as being provided only for manual operation. A separate master switch 74 arms the entire circuit and operates the lamp 4.

The box around switches 72, 73 and 74 in FIG. 9 is to indicate that this portion of the control is housed in a separate and portable housing, connected by cable to the rest of the apparatus, for the convenience of the practitioner.

Still referring to FIG. 9, it will be seen that there are, in association with switches 72, a plurality of normally open switches 73 which are disposed in parallel relationship to switches 72. These switches 73 are operable independently of switches 72 and provide electrical connection to their respective motor windings so that when switch 73 is closed and 72 open, the corresponding motor rotates oppositely from the direction of rotation when switch 72 is closed and 73 open. Thus, slide discs 12, 14 and 16 are rotatable in either direction. This is in addition to the alternative continuous or stepping modes of operation above-described.

In the operation of the refracting chart projector as abovedescribed, when switch 74 arms the circuit and turns on lamp 4, discs 12, 14 and 16 can be positioned as desired by operation of their respective switches 72 or 73. By manually closing and holding a certain switch '72, for example, the corresponding motor will rotate continuously. As soon as switch 72 is released, that is to say opened, the corresponding motor will stop at the next cam actuation. In other words, motors 62, 64 and 66 can be rotated either continuously or in discrete or incremental arcuate movements, depending on the manner of use of their switches 72. The foregoing description of the function of switches 72 also applies to switches 73. Switches 72 actuate their motors in one direction, and switches 73 in the opposite direction. Incidentally, it will be appreciated front the circuit diagram that when switches 72 are closed, switches 73 cannot be closed, preventing any possible attempt by the circuitry to motivate a motor in both directions simultaneously.

The apertures of the discs 12, 14 and 16 are disposed one at a time in optical axis 7. It will be appreciated that there will always be one slide aperture of each disc aligned with axis 7. This means that, to project a given slide in a given disc without interference, the other two apertures of the other two discs which lie in the optical axis must be clear of targets. Accordingly, in each of the discs 12, 14 and 16, there must be at least one clear aperture. In order that the projection lens 5 can focus on targets in dials 14 and 16, as well as dial 12, focus is made at the plane of dial 12 and blocks of glass mounted in the clear apertures of dial 12, one block of glass of a first thickness for focusing dial 14 and one block of glass of a second thickness for focusing dial 16. These glass blocks, e.g. block 23 shown in FIG. 4, effect the shifting of the focus of projection lens 5 to the plane of the desired dial.

From the foregoing description, it will be apparent that a refracting chart projector has been rovided which enables a practitioner to pro ect slides or 0 arts of his choosing by remote control and that these charts are selectively retrievable.

It may occur to others of ordinary skill in the art to make modifications of the present invention which will lie within the concept and scope thereof and will not constitute a departure therefrom. Accordingly, it is intended that the invention be not limited by the details in which it has been described, but that it encompass all within the purview of the following claims.

What is claimed is:

1. A slide projector having a plurality of rotatable coaxial disks each defining a plurality of slide apertures disposed peripherally therearound and positionable one at a time in the optical axis of said projector,

each of said disks being separately geared to a motor for rotation therewith,

control means to effect motor operation in continuous and incremental modes of rotation in either direction,

one of said disks having an individual slide cell rotatably mounted relative to the disk and disposed coincidentally with one of said apertures, said slide cell being geared to a motor for rotation therewith relative to said disk,

each of said disks defining a clear aperture enabling a slide to be projected from one of the other of said disks,

one of said disks being normally in focus relative to the projector optical system and carrying a block of glass in two of its apertures for the proper shifting of the projection focus for the other disks,

each of said disks being operatively disposed relative to a switch for the energizing of its respective motor, each of said switches being cam actuatable by its respective disk so as to be opened only at the normal position of the disk and closed at all other positions thereof,

whereby the various slide carrying members are automatically returned to a normal or starting position and the lamp is switched off when the operating switch is moved to the off position.