US251719A - Crucible - Google Patents

Description

(N0 Model.)

M. H. KNAPP.

GRUGIBLE.

No. 251,719'. Patented Jah. 3,1882.

N. PETERS. PnulmLiumpmpher. wnshingion. D. C.

UNITED STATES PATENT OFFICE.

.MII/PON. H. KNAPP, 0F ADRIAN, MICHIGAN.

CRUC l BLE.

SPECIFICATION forming* part of Letters Patent No. 251,719, dated January 3, 1882.

v Application tiled September 28,1881. (Nomodel.)

To all whom it may concern:

Be it known that I, MILTON H. KNAPP, of Adrian, in the county of Lenawee and State of Michigan, have invented an Improvement in Crucibles, of which the following is a specification.

The nature of this invention relates to cer# tain new and useful improvements in the manufacture of crucibles especially designed-for dentists and jewelers use in melting metals7 although I intend not to confine myself to the small crncibles used in those professions, but make them of any size required. In such crucibles the metal is usually melted under the action of heat directed and accelerated by the blast of a blow-pipe, and this strong blast, intensifying the heat as it does, has a tendency rapidly to destroy and render `entirely useless the best crucibles now to be found in the market. The object ot my invention, therefore, is to provide a Crucible which will not be injured or destroyed under those circumstances.

Figure 1 represents a crucible for dental purposes unattached. Fig. 2 represents the same in a ladle or metallic Crucible with a handle, by which to support it.

In the accompanying drawings, which form a part of this specification, A represents a crucible for dentists use, in which to melt metals employed for dental purposes. The main feature of this Crucible is in the employment of asbestus in its construction. This may be done by the use of what is known as mill-board, which is made of asbestus ber mixed with a little paper-stock. When made of this board the heat to which itis subjected in use will destroy the paper-stock, and then, if undue pressure is brought to bear upon the crucible, it

will break down unless supported in a ladle or other suitable device, as shown in Fig. 2.

I do not desire to conine myself to the use of mi`il-board, for the asbestus ber may be pressed into the required shape under proper pressure and in suitable dies, and in such case the crucible thus formed would be necessary to be sustained by being placed within a metal Crucible or ladle.

I am aware that it is not new to protect cru- Cbles with an outer coating` or shieldl of asbestus, and therefore Ido not Clai In such invention.

What I Claim as my invention is l. A Crucible composed ofasbestus ber and paper'stock mixed and molded into shape, substantially as described.

2. A crucible made in two parts, the inner one composed of asbestus fiberand paper-stock mixed and pressed into shape and the outer part made of metal for supporting the inner part, substantially as described.

MILTON H. KNAPP.

Witnesses:

C. A. S'IACY, A. L. MILLARD.

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