US761420A - Stereoscope cross-bar. - Google Patents

Description

PATENTED MAY 31, 1904.

J. T. SMITH, STEREOSGOPE (moss BAR.

APPLIOATION FILED OCT. 23, 1902.

N0 MODEL.

WITNESSES} zm Ezvroze.

I BF I 04 5 6. AEQ LU'LL ATTORNEY.

i No. 761.420. I

D STATES PATENT OFF CE.

Patented May 31, 1904.

STEREOSCOPE CROSS-BAR.

SPECIFICATION forming partof Letters Patent No. 761,420,-dat,ed May 31, 1904.

v Application filed October'ZS, 1902. Serial No. 128,517- (No model.) I

1'0 all whom it may cbncernk- 7 Be it known that I, JOHN THOMPSON SMITH, a citizen of the United States of America, and a resident of the city and county of New Haven, in the State of Connecticut, have invented certain new and useful Improvements in Stereoscope Cross-Bars, of which the following is a specification. 2 v 3 v To secure the best results in using the stereoscope it is desirable that the views or pictures being examined should be held'always in substantially the same position relatively .to the axis of each lens. As ordinarily constructed 'the brace or receptacle wires at the ends of the cross-bar are at a suffici'ent distance apart at each end to permit the ready insertion of the card or cards of views, and the cross-bar hasa smooth upper surface. When .the instru-ment' is "being used with only a single card in position, the lower edge of the card is liable to slip back and forth between the brace wires, and thereby change its position relatively to the focus of either lens, and the card will also be thrown at an inclination to the axisof the lens, which will distort the-picture to a greater or less extent. Where the wires are so short as to reach only aportionof the way to the top of the card, as is usually the "case, this tipping becomes very objectionable owing to the great distance to which the top of the card may move, and when the rear end of the shaft of the instrument or the end carrying the cross-bar is raised above the hori-' zontal the top of the card will fall forward,

and thereby throw the picture into the shade.

I have, discovered that by providing a stop or abutment for the lower edge of the card on the cross-bar the card will be held more nearly in a vertical position at all times and tures. Y In addition to this, when two or more cards are placed betweenthewires, as is most desirable, and especially when there is an attendant for placing the cards in position,'the

upper edge of the rear card will be held at a slight distance above the top of the forward card. whereby the cards may be the more readily separated for removing the forward card, which is done by placing the thumb or finger on top of the rear card and drawing it back a sufficient distance to admit of. the insertion of the fingers between the 'two'cards to grasp and remove the forward card.

My invention therefore consists in providing a stereoscope withmeans in addition to the receptacles or wires for holding the pictures ina vertical position on the cross-bar, a s-will be hereinafter more particularly set forth. a W 7,

1n the accompanying drawings, infwhich the same reference-numeral indicates the same part in eachof the views in which it occurs, Figure 1 is a broken perspective view of my stereoscope with 'a card in position and the top of the bar provided with astop made according to my invention. Fig.2 is a similar view'of Fig. 1 with two cards inposition' l Fig. 3 is an end view of my improved crossbar; and Fig. i is a view similar 'to Fig. 1, but without a card, showing the top of the bar entirely exposed and provided with a longitudinal groove.

Referring more particularly to the drawings, the numeral 2 indicates a vshaft partly cut away of an ordinary stereoscope, (not shown,) said shaft having the usual lenses at the forward end thereof and a cross-bar 3 loosely mounted, so as to be moved toward and from the other end of said shaft. Braces or wires are located at the respective ends of this cross-bar to form receptacles for the picture- 'card. Each of these wires, as is well-known,

clined upwardly from the front to the rear, so'that when a card is placed between the receptacles its lower edge will automatically move forward until it enters the deepest part of said groove and rests against its front wall 8, which is preferably formed at a short distance to the rear of the front legs of thereceptacles. The rear edge of the groove 7 preferably comes to the surface of the top of the cross-bar 3 forward of the rear legs of the receptacles, as at 9. Instead of providing the top of the cross-bar with a groove having an inclined bottom the entire surface, as a substitute, can be inclined and the stop formed by this inclined surface, as will be understood.

By constructing the cross-bar of a stereoseope in this manner it is evident that when a card is placed between the receptacle-wires its lower edge will automatically slide down to the bottom of the inclined surface, where it will remain substantially stationary while being viewed irrespective of the movement or change of position of the instrument which is liable to occur while being held in the hand of the observer. By thus locating the stop intermediate the front and rear legs of the receptacles the lower edge of the card will be held stationary and will thereby reduce the angle of inclination which the card may assume as the upper portion moves back and forth between the tops-of the receptacles. In addition to these advantages with a single card when two or more cards are being used the rear card will rest upon the rear or upper portion of the groove, which will cause its upper edge to project slightly above the top of the forward card, as shown in Fig. 4, in

which position it can be more readily engaged by the thumb or fingers and bent back a sufficient distance for the insertion of the lingers to engage with and remove the forward card. As soon as the forward card has been removed the rear card will automatically move forward to take its place, and thereby give room for the insertion of another card.

Having described my invention, what I claim, and desire to secure by Letters Patent of the United States, is-

1. In a stereoscope, a cross-bar provided with a groove in its upper surface of sufiicient width for receiving a series of exhibitcards and extending throughout the length of the cross-bar, the front wall of said groove being arranged at an approximately vertical plane, and the bottom thereof inclining upwardly and rearwardly from the lowermost portion of said front wall to the upper surface of the cross-bar and extending throughout the length of the groove, whereby the foremost card is maintained in abutment against said front wall by the cards arranged in the rear thereof.

2. In a stercoscope, a cross-bar provided with a continuous groove in its upper surface for receiving a series of exhibit-cards, the front wall of said groove being arranged at an approximately vertical plane, and the bottom thereof inclining upwardly and rearwardly from the lowermost portion of said front wall to the upper surface of the crossbar, in combination with receptacle-wires at the ends of the cross-bar in line with said groove.

. 3. A stereoscope cross-bar provided with a guideway for automatically moving the foremost of a series of cards forward, comprising a grooved top for the bar, said groove being continuous from end to end of the bar, and having an inclined bottom extending throughout its length, and of suflicient width for receiving a series of cards thereupon.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN THOMPSON Sllll'lll.

Witnesses:

BERTHA BAOI-IAUT, HENRY E. MARSH.

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