US2400343A - Beam compass - Google Patents

Description

R. M. 'ESKIL BEAM COMPASS May 14, 1946.

Filed Sept. 13, 1943 v INVENTOR.

ATTORN E'Y.

Patented May 14, 1946 ,j UNITED STATES OFFICE -2,400,s43 r f BEAM doMPAs's f. Rolf MrEshil, Phoenix,- Application September 13, 1943-, Serial N0." 502,115 '4'Claims; (01. 33 -47)? Thi invention relates to abeam compass or to a device for scribing or drawing arcs of great radius'.

v An object of the invention is to provide an improved beam compass which is of relatively simple and durable construction and whichcan beeconomically manufactured'which employs a housing within which a steel tape is normally disposed; The steel tape may .be withdrawn from .the,housingI to the) desired length and clamped in-adjusted position, ,A. centering device is" associated with the housing 4 and a scribe. or marking device mounted on the free end of the steel-tape. r I

By meanspf the present construction asturdy type of beam compass is provided which will not only accurately scribe arcs .of great radius,- but in additionthereto, arcs may be traced or redrawn without variation.

Another object of the invention is'to provide a beam compass wherein a fine adjustment is possible in addition to the rough adjustment accomplished by the withdrawal oiv the tape from the housing and the clamping of it in its withdrawn position. 7

Still another object of the invention is to provide a beam compass wherein the body of the housing and its cover can be conveniently as-" sembled and form a simple and durable guide for the tape and the -meansfor clamping as well as a guide for the adjustable arm that carries the center.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawing for an illustrative embodiment of the invention, wherein:

Figure 1 is a view inside elevation of the improved beam compass embodying the present invention; e i

Fig. 2is atop plan view of the same;

Fig. .3 is a sectional view taken substantially upon the line 3-3 upon Fig. 1 in the direction indicated: and r Fig. 4 is a viewin end elevation of the beam compass or may be regarded as taken upon the line 44 upon Fig. 1 in the direction indicated.

Referring to'the accompanying drawing wherein similar reference characters designate similar parts throughout, the improved beam compass comprises a housing preferably formed of a block In of some cellulos plastic, such as for example, Lucite. This block has parallel sides and a relatively large aperture therethrough within which is normallydisposed a steel tape H. 'The steel tape ll may be of any preferred construction or design but preferably it is of that type of tape that is transversely curved so that when the tape is inwithdrawnor extended position the, transverse curvature effectively stiifens it to cause the tapeto have a truss efiect. On the free end'of the tapethere issecured a block [2 preferably 'also'f'ormed of Lucite which is bifurcated or split as at I3 providing opposed jaws which may be caused to clamp on a scribe or lead [4 on the tightening of a tightening screwor bolt l5.

The"bottomofltheaperture in. the block 19 which'houses't'hetape is substantially tangent .15

to the botto nvsurfacejof. the block and a ,U- shaped cover] IS fits over the bottom of the block providing sides foxthe aperture and a bottom I! that guidesthe tape H as itis withdrawn.

The forward side of' the block'is split as at H! and a tightening screw or bolt l9 extends-across the sides of the cover it through the split portion of the block. Preferably, the cover I6 projects forwardly beyond the sides of the block as indicated at 20 to provide an edge of index against which the graduations on the scale may be read. Similarly, the cover I6 projects rearwardly as at 2| to provide a guide for a resilient arm 22 which preferably is formed integral with the block l0.

$6 This arm isconnected to or anchored to the block In adjacent the upper forward corner thereof as indicated at 23 and extends rearwardly over the top of the block I!) in spaced relation thereto, down adjacent the rear side of the block and provides a rearwardly extending split portion 24 equipped with a tightening bolt or screw 25 so that it may be clamped upon a needle 26 that constitutes a center.

A stud 21 extends through the downwardly extending portion of the arm and into the rear face of the block I 0. It is equipped with a nut 28 which can be rotated to spring the arm and thus adjust its position. One or more indices 29 may be formed on the sides of the rearwardly extending portions 2| opposite graduations 30 on the bottom of the arm '22. If desired, a

vernier scale may be employed at this locality..

In use, the needle point 26 is used as a center. The tape is withdrawn the desired distance and is clamped in this position by tightening the of the tape which is wound about a transverse bolt 3| which connects the sides of the cover l6 through the center of the aperture in block II].

It will be noted that the resilient arm is anchored to the block at a point remote from the center or needle 26 so that adequate spring of the arm is normally inherentl in the arm because of its length, This may be supplemented however by interposing a compression spring 32 between the rear sides of the block 10 and the bottom of the arm. 7

From the above-described constructionitwill be appreciated that an improved beam compass is provided which is of relatively simple and durable construction and which can be economically manufactured and assembled. A fine adjustment is permissible, the lower end of the arm moving in a substantially straight line direction because of the effective length of'the arm from the center 26 to the point of attachment at 23. The cover IE not only serves to provide sides for the aperture and a guide for the tape but cooperates with the sp'litportion at [8 of theiblock' in clamping the tape in withdrawnposition.

In placeiof a scribe or lead l4 any other marking device, such as a pen, might be employed and any equivalent center means may be substituted for the needle 26. I

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by'the appended claims.

l. A beam compassco'mprising a 'body constituting a housing, a steel tape adapted to assume a retracted position within the housing or be withdrawn therefrom, means on the housing for clamping the tape in Withdrawn position, ascribe on the tape, a center mountedon the housing for adjustment towardand away from the housing, and means on the housing sli dabl embracing thesides of the center mounting,

2. A beam compass comprising a bodyhavi'ng therein, said body having an opening in its bottom through which the tape may be withdrawn,

a U-shaped cover disposed about the body closing the ends of said aperture and cooperating with the body to define a passage through which the tape may slide as it is withdrawn, the sides of the cover projecting beyond the body, a resilient arm secured to the body having a portion slid-ably disposed between the projecting portions of the sides of the cover, means for adjusting the arm toward and awayfrom the. body, a scribe on the end of the tape, and a centerfon said portion ofthe arm.

4. A beam compass comprising a body having a transverse aperture therethrough adapted to accommodate a steel tape, a steel tape disposed therein, said body having an openingin its bottom through whichthe tape maybe withdrawn,

a U-shapedc'ove'rj disposed about thebody closin'g the ends orsaieaperture 'andc'oop'e'rati' g withthe body to define'a passagethrough which the tape may slid'e'as' it'is' withdrawn, said body' being split adjacent the passage, means extending through the body adjacent the splitportion thereof for causing the; split portionto clamp on the tape in its withdrawn position, 5 cri e on the end of the tape, and an adjustable center on the housing. 7

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