US1679764A - Magnetic compass - Google Patents

Description

C. H. COLVIN MAGNETIC COMPASS Filed Oct. 11. 1922 Aug. 7, 1928.

UNITED STATES PATENT OFFICE.

enemies H. COLVIN, or B COMPANY, A cormz'rn'ansnrr ROOKLYN, NEW YORK, ASSIGN'OR TO PIONEER INSTRUMENT GONSISTING OF CHARLES H. COLVIN, BEIGE H.

GOLDSBOBOUGH, AND MORRIS M. TITTERINGTON, OF BROOKLYN, NEW YORK.

Application filed October 11, 1922. Serial No. 593,696.

invention relates passes,

MAGNETIC compassto magnetic comand more particularly to the magneticelements of compasses of the movlng card type. my drawings The magnetic and described in the following element shown m paragraphs is of the general form disclosed 1n my Patent #1,33 1,27 3 issued March 16, 1920. The improvements made are not lunited, however,

An object of my to this type of compass.

invention is the improvement of the magnetic element of a compass, and of its mounting. Further objects are to make such a magnetic element easy to construct,-lig'ht, in weight and. of low speclfic gravity, strong enough to be easily handled in manufacturing, well damped in its oscillations when submerged in liquid, and secure in its mounting. Other tages will appear as the after disclosed.

objects and advaninvention 1s herein- Referring to the drawings, which illus tratewhat I now consider a preferred form of this invention:

Figure 1 represents a top view of the magnetic element and support,

Figure 2 section, as at 2-2 in Figure 3 represents section, as at represents a inverted cup upon side view, partly in Figure 1, and a side view, 3-3 in'Figure 1.

Referring to the drawings, part which are marked the partly in 11 is an compass cardfi 12 and 13. The cup is preferably of a cellulose material, such as is commonly known as lin. The cards are thereon while and this part (11) cup as shown; ma be pivot bushing 17 part-11 is in fiat is then formed into a The markings of the card painted with radio-active material to render them visible at ni Part 14 is a carrier to celluloid or pyrapreferably prmted sheet form,

%lta w 'ch is attached 15 and 16, and the he cup 11 is removably attached by means of the screws 18.

The

magnets are clamped or soldered in place,

and the bushing 1 is riveted or soldered or both. At the lower end of the bushing 17 is attached the center of the the cup 19 forms a part. The jewel bearing rests is secured in part the hemispherical cup 19. In bushing 17 is fastened the pivot 20, whose point approximately cides with the center of the sphere 0 coin- Wl'llCh 21 in which part 20 22 which acts as a .the liquid 35, which is troleum or asphalt base plunger in' socket 23.- The plunger 22 is supported on a spring 24 and has extending from its lower end a wire 25 the extremity of which is bent at right angles, lying in a slot 26 in the end of the socket 23. A hole 27 communicates from the spring chamber in socket 23 to the outside.

At the upper end of part 22 is a jewel cap 28. Below and 29 are secured solidly to part 22. To collar 29 are removably attached retainers 30 and 31, by means of screws 32.

At 34 is shown a fragment of the compass bowl to which socket 23 is attached. The entire magnetic element is surrounded with contained in the or a similar peproduct, is a precompass bowl. Kerosene,

ferred liquid.

' In a magnetic compass it is important if not essential that both the absolute weight, and the net weight on the pivot (the difference between the two being due to the buoyant'efi'ect of the liquid) be kept at a minimum, with the magnets as the major item of weight. It is also particularly desirable to keep the moment of inertia of the element as low as possible: .that is, it is important to reduce the weight of those parts which are at the greatest distance from the center. This is accomplished by luloid cup 11, the specific gravityof which is of the nature of 1.4 as compared to water.

The specific gravity of the filling liquid (say,

kerosene) is approximately 0.7, which there fore reduces the effective weight of the cup by one-half. Since this cup comprises the J only structure at a distance from the center,

high. 1

he carrier 14 constitutes an improvement in construction, as it provides in a single element a means of inter-connecting the magnets, cards and pivot. 1

Parts 19, 30 and 31, in combinationwith the pivot 20 and jewel 21' provide a means of preventing the magnetic element from becoming disassociated from the mounting ost.

The jewel cap 28, in combination with the above elements, acts as a guide for the pivot 20, and assures its contact with the polished this is a collar 29. Both 28' the use of the cel- I claim as new is:

Claims: y

1. In amagnetic compass, in combination, a magnetic element, and supporting means for said magnetic element: comprising a plunger, a cup-bearing mounted therein, a

socket in which said plunger is carried, elastic means between said plungerand said socket, a axial extension on said plunger terminati g in a positioning element, an extension on said socket member terminating in a slot in which said positioning element is contained, and said socket having a pas sage connecting from the inside to the outside of said socket.

2. In a magnetic compass, in combination, a magnetic element, and supporting means for said magnetic element: comprising a plunger a cup-bearing mounted therein, a

' socket 1n which said plunger is carried,

elastic means. between said plunger and socket, an axial extension on said plunger terminating in a positioning element, and an extension on said socket member terminating in a slot in which said positioning element is contained.

3. In a magnetiecompass, in combination; a magneticelein'ent, comprising a cup composed ofcellulose material, indicating cards marked thereon,n1agnets, pivoting means, a

supporting member connecting said cup,

magnets and pivotingmeans, means for re- 'movably attaching said cup to the supporting member, means for attaching said pivot ing member to the supporting member; supporting means for the entire magnetic element, comprising a-plunger, a cup-bearing mounted therein, a socket in which said plunger is carried, elastic means between said plunger and said socket, an extension on said plunger terminating in a positioning element, an extension on said socket member.

terminating in a slot in which said'positioning element may be contained, sald socket having a'passage communicatingfrom the socket chamber to the outside of the socket;

and retaining means, comprising in combination with the before-mentioned pivoting means and cup-bearing, a cup attached to the pivot and substantially concentric therewith, covers attached to said plunger for retaining said cup means for guiding "said pivot into saidcup-bearing; and a liquid.

contained in said compass, and surrounding the above mentioned elements. 4

A. A magnetic compass comprising in combination, a magnetic element, means including a pivot and bearing for supporting said element, retaining means for said element, said retaining means comprising a cup attached-to said pivot and substantially concentric therewith, and a plurality ofcovers attached to said supporting means for retaining said cup.

5. A magnetic compass comprising in combination, a magnetic element, means including a pivot and bearings for supporting said element, retaining means for said element, said retaining means comprising a cup attached to said pivot and substantially concentric therewith, a plurality of covers attached to said supporting means for retaining said cup, and means for guiding said pivot. into said bearing.

6. A magnetic compass comprising in combination, a-magnetic element including a cellulose cup having two cards, permanent magnet means connected to said cup, means including a pivot and support therefor for supporting said magnetic element, a second cup secured to said pivot and substantially concentric therewith, and retaining covers attached to said support and surrounding said second mentioned cup.

7. A magnetic compass comprising in combination, a magnetic element having two cards, permanent magnet means connected to said cards, a support, means pivotally mounting said element upon said support, a cup attached to said pivotally mounting means and substantially concentric therewith, and covers attached to said support for retaining said cup.

8. A magnetic compass comprising in combination, a support post, a pivot resting thereon, an arched carrier straddling the pivot and post and fixed to the pivot, parallel arms integral with the arched carrier extendingdownward to either side of the post, a fiat rest integral with the arched carrier and each arm, a compass card centrally apertured and disposed on 'the'flat rests with the arched carrier projecting up through the card, and magnets carried by the arms.

' 9. A magnetic compass comprising in combination, a support post, a pivot resting thereon, an arched carrier straddling the pivot and post and fixed to the pivot, a pair of cooperating retainer cups movable relatively to each other but connected and held together against separation,means attaching one cup to the arched carrier, means connecting the other cup .to the post, parallel arms integral with the arched carrier extending downward to either side of the post, a flat rest integral with the arched carrier and each arm, a compass card centrally apera combination, a compass indicating means, a '11. A compass as tured and disposed on the fiat rests with the duced in diameter to prevent withdrawal of arched carrier projecting-up through the said inverted member et permit universal 15 card, and magnets carried by the arms. 1 freedom of movement between the inverted 10. A magnetic compass comprising in member and upstandintg1 device.

de ned in claim 10 furpost supporting the indicating means, a ther restricted by making the said upstandpivot interposed between the indicating ing cup-shaped device in a plurality of 20 means and the post, an inverted hemispherisections. cal member fixed on the indicating means Signed at Brooklllyn, in the county of and embracing the pivot, an upstanding cup- Kings and State of ew York this 10th day shaped device fixed on the post embracin of October, A. D. 1922. the inverted hemispherical member, and sai upstanding cup having its upper rim re- CHARLES COLVIN.

Images