US75106A - Whom it mat concern - Google Patents

Description

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WILLIAM AL'LENDER, OF NEW LONI0N, CONNECTICUT.

Letters Pate-nt No. 75,106, dated Zifarck 3, 1868.

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TO ALL- WHOM IT MAY CONCERN:

Be it known that I, WILLIAM ALLnNDnR,of New London, in the county of New London, and State ot Connecticut, have invented certain new and useful Improvements in Casting Aluminum Plates on to Artificial Teeth, and uniting 'the two firmly without risk of fracture from the exceedingly contractile nature of that metal; and that the following is a full, clear, and exact description ot the same, reference being had to the accompanying drawing, making a. part of this specification, in which- -I Figure 1 represents in perspective a set of teeth on or in an aluminum plate, made after my general plan.

Aluminum possesses, in a high degree, many essential properties requiredin dentistry, and especially in plates for holding artificial tecth,as follows: It is light, very stiii', anti-corrosive, is rendered luid at a low temperature, and susceptible of a. high finish. But, owing to its very great contraction in cooling, it has heretofore beeny found impossible, except by accident, to cast it upon other substances without fracturing itseif, or the substance on which it is cast, by its contractile force.

After much experiment in the use of'aluminum for plates for holding artificial teeth, I have discovered a mode of casting this metal upon teeth which entirely avoids the risk of fracture, and enables me to introduce its use in dentistry withl great advantage and economy. V i

My invention consists in providing means for compensating or talringup the extraordinary contraction of aluminum in casting it upon teeth, so as to avoid fracture of the metal or of the teeth, and thus utilizing in dentistry a metal havingmany valuable qualities for that art, but which has heretofore, in practice, been found impracticable on account of its immense contraction in cooling, and which exceeds that of any other metal available in dentistry. v

An indispensable element` in the economy of dentistry is to form or cast the mouth-plate upon the teeth, so that the act of casting shall firmly unite the teeth to said plate. This makes a firm, substantial union, not attainable by other separate appliances without very great labor and expense. And my invention embraces this plan of casting, but in connection with a metal (aluminum) which from its very nature opposes such process, as above mentioned, from the diiculty in arresting or compensating for its immense contraction in cooling.

To enable others 'skilled in the art to make and uso my invention, I will proceed to describe the same with reference to the drawing. i

Having articulated or antagonized the teeth, I separate the blocks of teeth, a ct a, so that the contrae-` tion of the aluminum, when cast upon them, will not, in cooling, break them The space left betweenl the blocks of teeth, when moulded, is covered by a strip of aluminum, or other metal or material, to prevent the encroachment or introduction of the molten metal, or any other substance used in moulding or casting, from entering said space which would prevent the blocks from coming together closely, and 'making a neat union. Iheprevcntionof any substance getting into the space between-thc blocks I prefer, but a. substance may be introduced into this space, which will yield and allow the blocks to come up close together, or which may be forced into cavities in the adjacent edges of such blocks when forced together,l the object being to prevent any such substance getting into the space as might in any manner prevent the blocks from coming close up, and thus closing said space.

To prevent the contractile force of the aluminum from acting on thc blocks individually, the portion ofthe teeth covered by the metal' must be so made or ground as to prevent the metal from grasping them, that is, there should bc no indented or ovcrhanging points or surfaces, but plain and tapering, or wodgc-shnped, so that the metal may draw or slip over such surfaces in contracting, wit-hout seizing upon them, which latter invariably results in fracture. And as the contractile force is towards the centre of the block, the pins or rivets inthe teeth or blocks should .all point towards the centre of the block, the centre one straight, and the others 'acutely bent towards it, which allows thc metal to slip from the pins or rivets in the line in which its contraction tendsA Itis better to so arrange the pins or rivets as that they will point towards thc centrc'oi` the block, or towards the line of greatest contraction, but the contractile force may be used to bend or point them in that direction, by putt-ing around them, in whole or in part, previous to the pouring of the molten metal into the mould, aluminum in wire,t`oi1, sheet, or otherwise shaped, or plaster of Paris, or other substance, near where they enter the blocks, to allow them to bend, when the contractile force comes upon them, and take the direction ot' that force.

Blocks of teeth may be made with a groove running parallel with or in the general direction ot' the cuttingedges or outer faces of the teeth, and the blocks may be set in a mould, together or slightlyiseparatcd, andthe molten aluminum poured into this groove, und its contraction being in the line of the groove, it-wouhl thus be prevented from obtaining a hold on the blocks and breaking them.

The moulds I prefer to use are so madens to allow the flow or casting of the metal around und beyond the Vouter face'o` the teeth, to counteract the effect ot' the contraction oi the central portion of the plate, or that part which is within the circle described-by the inner face of the teeth. The moulding of the teeth preparatory to the pouring of the aluminum around them does not diii'er, otherwise than heretofore mentioned, from the moulding of teeth for other cast substances, except such additional preparations as the use of this peculiar metal (aluminum) demand. l

The contraction et' the metal may be regulated also by means of currents of ai-r or water carried into the moulds or any part thereof` which it ismost desirable to so operate upon, and may be. done by layingwax in the mould, which, `when melted out, will leave a channel or space, through which it may be carried or forced; and

i the strain, or a portion of the strain, of the contractile forceo` the aluminum, maybe taken from the teeth by laying in proximity to or in contact with the teeth, pieces or strips of metal, which strips shall oppose the force of the contracting metal. The teeth may bef-asten ed to these strips, which may be twisted or worked together, or, if single strips, screw-cut or otherwise.

As, from the very light specific character of this metal, (aluminum) and the low temperature yrequired to put it in a Huid or molten condition, its natural flow is very sluggish, I may or can use a type-founders pump, or forcing-apparatus, to force the metal into and through the moulds.

The mould or form of teeth, when ready to receivethe molten aluminum, may be heated, as is usual in other processes of casting. l

Having thus fully described my invention, what I claim therein as new, and desire to secure by Letters Patentis- 1. In combination with the pouring of molten aluminum to form a base for artificial teeth, the so making or grinding ofi` the blocks of teeth,'desi'gned for the reception of molten aluminum as a base, as that the metal cannot seize or gripe, but slip upon, Vthe teeth or blocks, in contracting, and thus prevent the fracture of the metah: or of the teeth, or blocks of teeth, substantially as described.

2. I also claim, in combination 1with teeth or blocks of teeth, on which aluminum is to be cast for a base, the pointing of the pins or rivets towards cach other, or towards the centre of the block, or in the line of the greatest contraction, substantially as described.

3. Iaiso claim, in combination with 4the moulding of teeth or blocks of teeth, or preparing them to receive molten aluminum, which is to form their base, the protected space between them, to guard against the entrance ofthe metal or other material, as described, so that the contractile force of the aluminum, in cooling, may draw them up together, or nearly so, substantially as` described.

WILLIAM ALLENDER.

Witnesses:

A. B. S'roncufron, EDM. F. BROWN.

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