|Publication number||US276732 A|
|Publication date||May 1, 1883|
|Filing date||Feb 10, 1883|
|Publication number||US 276732 A, US 276732A, US-A-276732, US276732 A, US276732A|
|Inventors||Alfred A. Trowbridge|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (5), Classifications (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
(No Mode l.)
- A. A. T ROWBR IDG'E.
No. 276,732. Patented May 1,1883.
7 UNIT D STATES PATENT OFFICE,
ALFRED A. TRO'W'BRIDGE, OF DANBURY, CONNECTICUT.
SPECIFICATION forming part of Letters Patent No. 276,732, dated May 1, 1883. Application filed February 16, 1883. (No model.)
To all whom it may concern:
BeitknoWnthat1,ALFRED A.TROWBRIDGE, of Danbury, Fairfield county, and State of Con necticut, have invented a new and Improved Optometer, ofwhich the followingis a full, clear, and exact description.
The object of my invention is to provide a new and improveddcvice for ascertaining the proper correction or remedy for those defects of sight which can be remedied by convex or concave spherical lenses.
This invention, which is an improvement on the optometer for which Letters Patent No. 262,151 were issued to me August 1, 1882, consists in various novel parts and combinations of the same, as will be fully described herein- 1 after.
' ing shown in longitudinal elevation.
Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.
Figure 1 isa longitudinal elevation of the outer side of thclens-holding face-plate. Fig. 2 is a cross-sectional elevation of the same on the line a: 00, Fig. 1, the hood and scale-rod be- Fig. 3 is a front view of the sight-card.
The face-plate A is provided with two apertures, B B, the centers of which are on a horizontal line, and are of such diameter and such a distance apart that the portion of the plate between the apertures B B will not obstruct the vision of the type or test card when it is nearest theface-plate. The face-plate A is provided with a vertical and grooved noseopeuing, 0, between and below the apertures B B, thus permitting the plateA to be held closely against the face, the nose passing into the groove and opening 0.
A hood, D, made of leather, pasteboard, fabric, or any other suitable material, and litting closely to the face, is attached to the faceplate A, and serves to exclude the light from the inner side of the face-plate when the same is set before the eyes and close to the face. The eye-apertures B B are beveled from the inner toward the outer surface of the face-plate A, as shown in Figs. 1 and 2.
In each aperture B there is fixed, near the inner surface of the plate A, a convex sphericallens, E, having a focal length oftwelve inches. i
Adisk or frame, F, made of metal orof other suitable material, and of sufficient size to cover either of the eye-apertures B B, and holding a convex spherical lens, G, having a focal length of six inches, is fastened to a springstrip, H, which is pivoted to the outer side of the faceplate A, between and above the apertures B, so that either of the apertures B can be cov- 6o ered by the said lens. The spring-strip H is pivoted to the plate A at such a distance from the centers of the apertures B that when the lensholding frame F rests against either side of a check-pin, 0, between the eye-apertures B, '6 the center of the lens G held in the frame F will be opposite the center of one of the lenses E in the face-plate A. Spherical lenses having other focal lengths than those named above may be chosen for the same purpose; but those 0 named will prove the most satisfactory. An opaque disk or shield, L, of sufficient size to cover the lens-holding frameF, is provided with a handle, M, and is fastened to a spring-strip, N, pivoted on the same pivot as the spring-strip of the frame F. The lensholding frame F and the opaque shield L are so constructed and. arranged that the shield L may be easily raised and turned, so as to cover the frame F, the spring-strip M pressing the shield L against the face of theframc F, which 1 is provided with raised spring clamps orguards it along the periphery for the purpose of bolding the shield L on the said frame. When the shield L and the frame or disk F are thus 8 placed they may be turned to cover eithereyeaperture B by means of the handle M, as though there were but one disk or shield. The lens-holding frame F being large enough to cover either of the eye-apertures B, and the 0 opaque shield L being large enough to cover the frame F, they will, when resting against either side of the cheek-pin O, entirely exclude the light from the front of the eye-aperture over which they rest. When the shieldLand the disk F are held above the eye-apertures-- that is, in such a manner that they cover neither-botheyes can be tested by the lens in the apertures at the same time. When the shield L and the frame F are turned so as to we cover one of the eyeapertures the eyes may be tested separately by the lens in the apertures B, the light from in front of the face plate A being prevented from entering theother eye, which is behind the eye-aperture B that is covered by the frame and shield. The construction and arrangement of thelens-holding frameF and the opaque shield L also allows the lens-holding frame F to be turned so as to cover one of the eye-apertures B andthe opaque shield L so as to cover and exclude the light from the front of the other eye-aperture B, thus permitting either eye to be tested by the combined power of the lens in either eyeaperture B and the lens in the lens-holding frame F, all light from the front of the faceplate A being thus prevented from entering the eye behind the eye-aperture covered by the opaque disk or shield. The plate A is attached to a frame, P, provided with a handle, Q, from which frame a rod, It,-projects in the direction of the outer side of the plate A, and the said rod is provided with an inch scale, or may be provided with any other suitable scale indicating the number of lens.
A sliding card-carrier, S, provided with a pointer, S, is loosely mounted to slide on the rod It, and carries the type or test card T. (Shown in Fig. 3.) This card is about six by four inches in size, and on the middle line of the card, under the word both, is placed a series of test types or objects, which cover a space of about one by one and one-fourth inch, Any suitable object or test may be chosen for this purpose, but those given are the most practically useful, as they may be printed from type obtainable in any printing establishment. The smallest test-objects used on the test-card T are words and disconnected letters printed from pearl type. The largest test-objects used on the card are printed with type three times the size of the pearl type. On the back side of the test-card T. are two series of test-objects, which are the same in size and arrangement as those on the v face of the card, except that instead of being placed in the middle they are at the ends of the card, one being at the'right-hand and the other at the left-hand end, and both being marked accordingly. The type on the face of the test-card T under the word both are used when both eyes arebein g tested together, and when the eyes are being tested singly the card. is reversed on the card-carrier.
The construction and arrangement of my optometer, as explained and set forth above, may be modified in the following manner: Instead of the single lens-holding frame F, pivoted to the face-plate A, so as to be swung over either of the eye-apertures B, two lensholding frames of the same kind and form as the frame F may be used, but so pivoted to the face-plate A that one of the lens-holding frames may be turned or swung so as to cover one of the eyeapertures B, and the other lensholding frame turned so as to cover the other eye-aperture, thus allowing both eyes [to be tested at the same time by the combined'powerof the lenses inthe eye-apertures B and thelenses in the frames F. Instead of pivoting the lens-holding frame to the face-plate, as described above, they may each be attached to the face-plate by a joint or hinge, which will allow them to be turned down upon the faceplate, so as to cover the eye-apertures, or to be turned back out of the way, as desired.
The instrumentis used in the following manner: The person whose eyes are to be tested holds the optometer by the handle Q, close to the face, the nose passing into the opening 0. If both eyes are to be tested together by means of the lenses E fixed in the face-plate A, the shield L is turned. so as to cover the disk F, and both the shield and frame are turned so as to rest above and between the eye-apertures B. If each eye is to be tested separately by means of the lens E, the shield L and frame F are together turned down, so as to cover either aperture, as desired. If each eye is to be tested separately by means of the combined power of one lens E and the lens'in the frame F, the said frame is turned so'as to cover either aperture B, as desired, and the shield L is turned so as to cover the otherapertnre B.
Having thus described my invention, Iclaim as new and desire to secure by LettersPatent 1. In an optometer, the combination, with an eye-apertured face-plate adapted to hold lenses, of a lens held in a frame pivoted to lens can be swung over either of the eye-apertures, substantially as herein shown and described, and for the purpose set forth.
2. In an optometer, the combination, with t the eye-apertured face-plate A, of the frame F, carrying a lens, G, and pivoted to the. faceplate, and of the stud 0,between the eye-apertures of 'the'faceplate, substantially as herein shown and described, and for the purpose set 1 forth.
3'. In an optometer, the combination, with an eye-apertured face-plate, of a frame holdving a lens and pivoted to the face-plate, and
of an opaque disk pivoted to the face-plate, and adapted to swing over either eye-aperture and over the lens held in the pivoted frame, substantially as, herein shown and described, and for the purpose set forth.
4. In an optometer, the combination, with the eye-apertured face-plate A, of the frame F, holding the lens G, and pivoted to the faceplate A, and of. the disk L, pivoted to the faceplate A, and provided with the handle M, substantially as herein shown and described, and for the purpose set forth.
5. In an optometer, the combination, with the eye-apertured face-plate A, of the frame F, pivoted to the face-plate holding a lens, G
and provided with spring-clamps n, and-of the disk L, pivoted to the face-plate, substantially as herein shown and described, and for the purpose set forth.
6. In an optometer, the combination, with the eye-apertured face-plate A, of the frame.
F, holding alens, G, the spring H, attached to the frame F, and pivoted to the face-plateA, the disk L and the spring N, attached to the disk L and pivoted to the face-plate, substan- 'the face-plate in such a manner that the said tially as herein shown and described, and for the purpose set forth.
7. In an optometer, the combination, with the eye-apertured face-plate A, having the lenses E, the grooved nose-opening O, and the hood D, of the shield or disk L, the frame 1, scale-rod R, and card-carrier S, substantially as herein showna'nd described, and for the purpose set forth.
8. In an optometer, the combination, with the eye-apertured face-plate A, having the lenses E, the grooved nose-opening C, and the hood D, of the frame P, the scale-rod R, and
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