US2221928A

US2221928A - Eye examining instrument

Info

Publication number: US2221928A
Application number: US248802A
Authority: US
Inventors: Elton H Rimington
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-12-31
Filing date: 1938-12-31
Publication date: 1940-11-19
Anticipated expiration: 1957-11-19

Description

Nov. 19, 1940. RIMINGTQN I 2,221,928

EYE EXAMINING INSTRUMENT Filed Dec. 51, 1938 Y FIG.2

ELTON H.RlMlN-GTON 'ATT s VENT R Patented Nov. 19. 1940' UNITED STATES PATENT OFFICE 2-Claims.

.The present invention relates to optical instrumeans. A further object is to provide a dynamic.

retinoscope having a moving fixation chart.' Still another object is to provide a self-illuminated retinoscope with a self-illuminated, motor-driven, fixation chart. 'These and other objects and advantages reside in certain novel features of const'ruction, arrangement and combination of parts 16 as will hereinafter be more fully set forth and pointed out in the appended claims.

Referring to the drawing: Fig. 1 is a vertical section of my improved retinoscope. v 29 Fig. 2 is a rear elevation thereof with parts broken away to show internal structure.

Fig. 3 is a fragmentary front elevation thereof. Fig. 4 shows the fixation chart.

One preferred embodiment of my invention is 25 illustrated in the drawing wherein in designates a conventional battery or transformer handle upon which is secured an adapter H. A conducting sleeve I2 is secured within the adapter H by a threaded sleeve l3 of insulating material 30 anda conducting ring it is fastened on the outside'of the insulating sleeve l3 ,by a screw i5.

This screw also provides an electrically conducting connection between the sleeve l2 and ring it. The sleeve I2 is connected to one terminal 35 of the battery or transformer, not shown, through a rheostat indicated at l6 and the other terminal of the battery or transformer is grounded to the adapter ll.

The adapter ll projects forwardly from the o handle l2 and has a cylindrical bore ll at'its outer end parallel to the bore l8 above the sleeve l2. A conducting sleeve I9 is secured in the bore ll and insulated from the-adapter H by a sleeve 26. A conducting screw 2! is threaded into the 45 lower endof the sleeve i9 and a second screw 22 is threaded through the head of the screw 2|. This screw 22 extends through a transverse bore 23 in the adapter II and makes contact with the ring I4. A nut 24 of insulating material holds 50 the screw 22 against contact with the adapter II. The instrument head'indicated generally at 25 has a. longitudinal bore 26 within which a socket member 21 is threaded. -The lower end 28 of this socket member 21-is of a size to fit snugly in the bore l8 and may be locked therein by a set screw 29. A lamp 30 having-the usual diaphragm hood 3| is secured in the socket at the upper end of the member 2'! and the contact 82 for the central terminal of the lamp 30 extends down into the sleeve l2. A condensing lens 33 is mounted in 5 the bore 26 above the lamp 30 and is secured against a shoulder 34 by a friction skirt 35.

Above the open end of the bore 26, the head is shaped to form a hollow casing 36. having an opening 37 in its front wall. A semi-reflecting l0 mi'rrorf38 is secured within the casing 36 by a ring 39 so that it reflects light from the lamp 8h out through the opening 31. A cover plate 40 is secured'over the rear end of the casing 36 by a screw 4! which is providedwith an enlarged head 15 to serve-as a foreheadrest for the operator. A sight opening 42 is provided in the cover plate fill in alignment with the opening 31. The interior walls of the casing 36 are made light-absorbing to prevent any undesirable reflections from the rear surface of the mirror 38 to the eye of the operator.

A housing $3 is formed on the front of the head below the opening 2i and a source of power such as a spring motor mechanism at is secured 25 within this housing 43 by screws t5. A disk 6% is mounted on the shaft 48 of the motor M. As shown in Fig. 4, this disk 56 has a plurality of rows of test characters 46' which are preferably of diiferent size. For example, the outer and inner rows might be of such size as to subtend the same visual angle at'the diiferentdistances ordinarily used in dynamic retinosoopy. The movement of the disk 66 by the motor M1 is a great aid to fixation as the successive movement .85.

of the characters before the eye holds the attention more readily than a stationary fixation object.

The motor 44 is asmall, slow-speed spring motor and I have found that the ordinary watch works is entirely satisfactory. The secondjlh'and shaft of a watch'rotates at a suitable speedand the disk 45 could be mounted on this shaft but since this shaft is relatively delicate and small, I prefer to modify the watch anismso that 45 one of the. central shafts can be Mounting the disk 46 on a central shaft also conserves space and makes the mechanism more compact;

In my preferred form, the escapement'mechanism is removed from the watch: works and the 5 speed is controlled by a fan 4?}; The disk 46 can then be mounted onthe minute hand shaft 48 which makes one to four orsfive revolutions per' minute under the control of theifan ll. A'wind 1 ing stem 49 is journalled in a. boss BG Jon the side 5 01 the housing 43 and is held against removal by a circular plate 5|. This plate 5! its in an aperture 62 in the boss and is keyed to the winding stem 49 by a pin 63. A gear 64 on the end 01 the stem engages the winding gear 01 the watch mechanism.

vIn order to start and stop the motor 44, a pin 66 is slidabiy mounted in a boss 61 -on the side of the housing '43 adjacent the fan 41. The end of this pin 56 is pointed and, when the pin 56 is pressed in, the point engages the fan 4'! to stop the motor 44, as shown in Fig. 2. The pin 56 has a reduced central portion 58 and a spring pressed detent 59 engages this reduced portion 58 to prevent withdrawal of the pin 56 from the boss 87. When the pin 56 is pulled out, that is, pulled toward the left as shown in Fig. 2, the fan 41 is released and the motor 44 operates to rotate the disk 46.

The front of the housing 43 is closed by a cover 60 which has an aperture 6| adjacent the opening 31. This aperture 6i is in alignment with the characters on the disk 46 and is sufllciently large that both rows of characters 46' can be seen. A diaphragm or masking plate 62 is fixed on a shaft 63 by a nut 64 and this shaft 63 is rotatably mounted in the cover 60. A knob 65 is fixed on the shaft 63 outside the cover 60 for convenient operation of the diaphragm or masking plate 62. This masking plate 62 has two spaced apertures 86 and 6'1. The size and location of the aperture 66 from the shaft 63 corresponds to the size and position of the outer row of characters on the disk 46 and the size and location of the aperture 61 similarly corresponds to the size and position of the inner row of characters on the disk 36. Thus, when" the aperture 66 is in alignment with the aperture 6|, characters of the outer row are visible to the patient and when apertures 6i and 6'! are in alignment, those of'the inner row are visible. The two apertures '66 and 61 are spaced apart by a distance greater than the diameter of the aperture 6| so that the aperture 6| may be closed and the instrument. used as an ordinary retinoscope. The masking plate 62 has a detent 68 at its lower end and this detent 68 engages selectively in the three

depressions

69, 10 and H to position the masking plate 62, respectively, to expose the outer row of characters, the inner row of characters or close the aperture 6| completely.

Within the housing 43 is an incandescent lamp 12 to illuminate the characters 46' on the chart disk '46. This lamp I2 is mounted in a socket 13 which is secured ina nut 14 by a set screw 16. The nut 14 is threaded into a tapped hole 16 in the bottom wall of the housing 43. The central terminal 11 of the socket 13 extends down into the sleeve IQ of the adapter ll- In operation, the two lamps-36 and 12 are lit and their intensity is regulated by the rheostat l6. The operator adjusts the masking plate or diaphr 62 to select the row oi characters suitable for the distance at which he is to work.

The pin 66 is pulled out and the motor 44 rotates the disk 46 causing the characters to move slowly by the

aperture

63 or 61. The patient is directed to watch the characters and the retinoscopy is performed in the usual manner.

From the foregoing, it will be apparent that I am able to attain the objects of my invention and provide an improved dynamic retinoscope in which the fixation object moves during the examination. While I have described a spring motor for moving the fixation object, obviously other 1 suitable forms of actuating mechanism could be used. Various other modifications can also be made without departing from the spirit of my invention or the scope of the appended claims.

I claim: 1. A retinoscope comprising a support, a retinoscope mirror carried by said support, a chart movably carried by said support adjacent said' tor carried by said support and operatively com nected to said chart to move said chart and present the characters in the exposed row successively at said one of said apertures.

2. A retinoscope comprising a support, a source oi light carried by said support, a retinosc'ope mirror'carried by said support for directing light from said source to the eye of a patient, a housing carried by said support adjacent the mirror, said housing having an opening facing the patient, a disk rotatably mounted within said housing behind said opening, a plurality of concentric rows of characters on said disk, the size of the characters in each row being difierent from the size of the characters in another row, a diaphragm plate movably mounted on said housing and having an aperture for each row of characters, means for moving said plate to bring one of said apertures into alignment with said opening to select a particular row of characters, and a spring motor mounted in said housing and operatively connected to said disk to rotate the disk and present the selected characters successively at said aperture.

H. RIMIN'GTON.