US103286A - Improvement in mariners compasses - Google Patents

Description

` 1. L G. H. Buss. Compass.

f Patented May 24, 1870.1

III/miam posed.

waited gieten 'stent Alilihzc.

Letters Patent No. 103,286, dated May 24, 1870.

IMPROVEMENT 1N MARINeas coMPAsses.

The Schedule referred to in these Letters Patentand making part of the same.

To all lvhom it may concern `Be it known that we, JOHN BLIss and GEORGE H. Buss, oi Brooklyn, in the county of Kings and State of New York, have invented and made a new and-useful Improvement in Liquid Compasses; and we do hereby declare the following to be a full, clear, and exact description of the said invention, reference being had to the' annexed drawing making part ofthis specication, wherein we have represented the said com-v pass by a vertical section of the same.

Liquid Compasses have, heretofore, been made, in which the case was lled with ralcohol or other liquid, so as to partially `float the card and needle, and the expansion of the liquid under varying temperatures has been allowed for by a portion. of the case, or a chamber connected thereto, being of thin sheet metal, and, in some instances, an air-chamber has-been pro- When the metal is moved by the expanding liquid the case cannot be made of thick metal, and the thin metal is liable to injury.

There au air-chamber has been used there was a liability for" bubbles of air to escape from the expansion air-chamber into 4the compass-case, or else the compass has been" rendered inconvenient or unsightly in consequence of the air-chamber being above the compass-ease, and this chamber obstructed l(he view ofr the cornpass-card.`

Our invention relates tovan air-chamber combined with the liquid-chamber of Vthe compass-case, the two being connected together by small openings or pores in the liquid portions of the chamber, in such a manner that only theliquid canpass from -one chamber to the other, in consequence vof expansion or contraction under varying temperature, and the air will be confined eiectually, but act as an elast-ie cushion.

In the drawing-'" a. is the bowlof the compass, formed of sheet metal spun up to shape, instead of being cast as heretofore, soas to be lighter and of `more dense and reliable metal, and not liable to leak.

The ring b is soldered or brazed to the upper edge of the 'bowl a, and receives the glass c, rubber or elastic packing d, and clamping-ring e, pressed down by screws.

f'lhe diaphragm f is introduced within the bowl a,- so that the'spaee for the liquid and compass-card will be lessened, but the swing of 'die card `will not bo interfered with.

Below the'diaphragm j' is the expansion vessel g, that is tov be filled with liquid to about the height shown previously, to introduce the tube h, thatis secured firmly to its scat upon 1", so as to be air-tight.

The lower end-of this tube h terminates near the center of the chamber or vessel y, so that it will always remain in the liquid, even if the compass is turned on its side, or inverted so that air will not enter z this tube. A As an additional precaution we make use of a screwcap, t, with a very small hole, that is sufficient for the liquid to pass gradually from one vessel to the other. The end of this cap c' is rounding, so that bubbles ofV air cannot lodge, even if the compass is shaken.

`Furtherrnore, we introduce porous material where the liquid passes from one chamber `to the other.

-lVe find that sponge introduced in the tube 7i., a l

piece of porous stone or packing of fibrous material, or-other like substance, applied between the said chambers,l will allow the liquid `to pass, but, being saturated with liquid, will not allow v`air to pass.

Small spring valves, opening inopposite directions when employed, are thc equivalent of the `porous Inriterial. l

'lhc porous materials or valves allow of the airexpansion chamber being located in some other part of the compass-bowl than the bottom thereof, suchy vas in the sides of the bowl or in the compass-card.

lhe'tube h is extended up, toform the pivot l.: for

the compass-card. The openings, 3, through the base oi' said pivot, communicate with thetube h.. The compass card is formed of' a sheet metal annulus, l, coated with vitrifed enamel. The necessary points and letters are formed and burnt in by vitrifying the cnamelina manner similar to that adopted in the manufact-ureof watch and'cloekaces.

This mode of making the compass-card insures great accuracy and beauty, and prevents injury to the -compass-case, either as to the color or the accuracy o i' the divisions, by the action of the liquid.

The annular' compass-card l is supported by the float nl, of cork or other wooden material, formed with a flange, 4, for the card to rest upon.

. v The magnetic needle n is provided with the conical socket for the pivot, as usual; said conical socket is shown as entering the cork-float m., and being retained by a nut, 5.

, i This cork or wood float projecting through the annular compass-card causes the weight to be partially floated, so that it does not rest so heavily on the pivot k, and there is no tendency to tip or incline the card," as there would be it' the floating power was entirely below the compass-card.-

A thin sheet-metal cap, Vo, may be placed over the float m, to render the appearancemore acceptable.

In order to prevent the cork or wood absorbing the liquid and lessening its buoyancy, we employ a coatl ing of collodion, mixed with :t pigment, such as zincwhite, and the same can he employed for painting the inside of' the bowl.

Alcohol does not affect said collodion, hence it is admirably adapted to this object. Y

Vhat we claim, and desire to securel by Letters Patent, is

1. A liquid compass, formed with two spaces, one for the compass-card, the other containing liquid and air, when the two are connected by a. tube or opening provided with porous material, or its equivalent, for preventing air passing into the compass-space, substantia-lly es set forth.

2. The chamber g, below the coinpass-chamber, in combination with the tube h, the opening of which is .located at or neer the center of -the vessel y, as and for the purposes specified.

In witness whereof we have hereunto lset our signatures this 3d day of May, A. D. 1869.

JOHN BLTSS. GEO. H. BLISS.

Witnesses GEO. D. WALKER, GEo. T. PINCKNEY.

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