Improvements in Compasses, Calipers, and Analogous Instruments.
Year: 1888

page_text: Date of Application, 14th Feb., 1888
Specification Accepted, 1st June, 1888
Improvements in Compasses, Calipers, and Analogous Instruments.
I, JOSHUA STEVENS, of Chicopee Falls, Massachusetts, in the United States of
America, manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention relates to compasses, dividers, calipers, and other analogous
instruments.
The improvements, pertain in part to the construction of the head or hinged joint.
of the compass, caliper, or other instrument, and in part to means for holding the
pencil or center-point or both of compasses, and for adjusting the length thereof,
and for lengthening or shortening the leg which carries the pencil or point.
According to the first part of my invention the hinged joint at the head (instead
of being made by interleaving or superposing the hinge portions of the two legs
and passing a pivot screw or rivet through perforations therein, or clamping them
between the points of opposite pivot screws, as heretofore) is constructed with the
hinge-part of each leg entirely on one side of the pintle, so that the two legs
approach each other on opposites sides of the pivotal axis with the pintle between
them, and the legs are pivotally connected through the medium of washers or caps
applied against the opposite sides of the legs and one (or both) of which washers is
formed with an annular concentric rib or groove interfitting with a reciprocal groove
or rib formed on or in the faces of the legs, whereby the latter are retained in position
and caused to turn properly around the pintle.
According to the second part of my invention one leg of the compass is constructed
with a pencil or needle socket and with a screw arranged at an acute angle to the
axis of said socket, so that when a pencil or needle is placed in said socket a nut
screwing on said screw can be turned down until it presses against the side of the
pencil and thereby clamps the latter in place. The leg is made adjustable in length
by constructing the screw to screw into it and fastening it by a set nut.
Figure 1 of the accompanying drawings is a front elevation of a compass constructed
according to my invention. In dotted lines are shown the legs of a caliper, to
illustrate the applicability of the first part of my invention thereto.

page_text: Fig. 2 is an enlarged transverse section of the head or hinge, cut on the line 2-2
in Fig. 1.
Fig. 3 is an elevation showing the upper ends of the legs brought together as they
are when the hinge is completed, and showing the pencil holder and adjusting devices
in section.
Fig. 4 is a plan of the annularly ribbed washer.
Fig. 5 is an elevation of the inner side of one of the legs.
Fig. 6 is a fragmentary view of a modified construction of the pencil holder.
Fig. 7 is a similar fragmentary view partly in section illustrating another modifi-
cation as applied to the holding of a needle point or center.
Fig. 8 illustrates a modification, being a view like Fig. 5 with the addition of
the respective annular washers to be applied to it, shown in diametrical section.
Fig. 9 is a section on the line 9-9 in Fig. 1 showing another modification, and
Fig. 10 is a plan of one of the washers used in Fig. 9.
Let A A designate the legs or arms of the compass, caliper, etc. B the usual spring
for opening the legs, C the screw and D the nut for closing them together, and F the
binge or head.
The spring B may be of any suitable construction. I prefer a spring made of flat
steel plate bent into circular form with its ends hooked outwardly, as shown. A. side
view of this spring, detached, is shown at the left of Fig. 1. The hooked ends of the
spring are forced into corresponding notches & formed in the legs just beneath the
head, as shown in Figs. 1 and 3.
The screw C and nut D may also be of any known or suitable construction.
I prefer the construction of quick-adjusting nut shown in the United States patent of
Stevens & Warfield, No. 351,474, granted October 26, 1886, to which reference may.
be made for a full understanding thereof.
I will now describe the preferred construction of hinge or head, which is shown in
Figs. 2 to 5.
The hinge end or head of each leg A is formed as best shown in Fig. 3, entirely
on one side of a diametrical plane coincident with the axis of the pintle a, (i.e. the
plane of the line 9-9 in Fig. 1) and to enable the two legs to be opened out to the
desired angle their upper ends above the pintle are beveled back as shown at ee in
Fig. 3. In each leg is formed a nearly half round cylindrical groove f for the
reception of the pintle. The legs are formed on one side of the head with a recess g
to receive a boss h on the head F of the pintle, and on the other side of the head the
legs are formed with an annular groove c, concentric with the axis of the pintle, as
shown in Figs. 3 and 5. The washer G, which fits against this side of the head, has
a concentric annular rib b which enters the grooves c in the manner shown in Fig. 2,
and thereby connects together the two legs and prevents any movement away from
each other, while at the same time permitting them to turn the one upon the other to
the extent provided for by the beveling away of the ends e. The head F and washer G
upon opposite sides of the head are connected together through the medium of the
pintle a which is made in one piece with the head and the opposite end of which
passes through the hole in the center of the washer and is rivetted down thereon.
The parts being accurately fitted together, a very perfect hinge joint is thus made,
which is subject to the minimum of wear and not liable to become loose. In case it
wears loose to a slight extent it may be tightened again by hammering down the
rivetted end of the pintle, and this is done without liability of injuring the hinge as in
the case of an interleaved hinge.
When the legs are closed together an angular gap is left between the bevelled faces e e
at the top, but this gap is concealed and protected by the broad plate spring B which
entirely encloses the hinged joint.
If preferred the head F may be made also with an annular rib b in lieu of its boss h,
as shown in Fig. 8. This figure also shows the end of the pintle a screw threaded in
order to be united to the washer G by screwing it thereinto instead of rivetting it.
In this case both the head and washer should be nicked to be engaged by a screw
driver.

page_text: While I consider it preferable to make the head F and pintle a both in one piece,
this is not essential, as the pintle may be screwed or rivetted to the head F as well as
to the washer G. Such a construction is shown in Figs. 9 and 10 which also illustrate
a modification wherein the grooves c c in the respective legs are mere annular rabbets
around the exterior of the head, and the ribs bon the washers are arranged at the
periphery thereof, so that the washers constitute in fact caps, which partially enclose
the ends of the legs on opposite sides of the head. Or, in other words, in this modifi-
cation the elements are reversed, in that an annular groove (lettered in Fig. 10) is
formed in the washer, and annular ribs or projections (lettered jj in Fig. 9) are formed
on the legs and fit into these grooves.
The pintle preferably fills the eye formed by the half round grooves in the respective
legs, as in Fig. 2, but this is not essential as the pintle may be made smaller than
these grooves, as shown in Fig. 9.
I will now proceed to describe the second part of my invention, which is applicable
only to compasses or other instruments fitted with a pencil or needle point.
The leg A of the compass in Fig. 1 is of the usual or any good construction and
may terminate in a point, as shown. The leg A2 embodies this second part of my
invention. It carries a pencil P which is held in a pencil holder L which is connected
to the leg A through the medium of a screw I and set nut p. These parts are best
shown in the lower part of Fig. 3. The screw I is fixed to or made as a part of the
holder L, and the end of the leg A2 is drilled out and tapped to fit this screw, which
screws into it. The set nut p makes the parts firm so that the screw 1 constitutes
substantially a continuation of the leg. The leg may be lengthened or shortened
by loosening the set nut, screwing the screw I out or in and again tightening the
set nut.
The pencil holder L is formed with an oblique hole or socket o through which the
pencil passes, and when the pencil is adjusted to the desired position in this hole it is
clamped in place by screwing down against it a coned nut J which screws on the
screw 1. Its clamping action is due to the axes of the screw I and hole o being
oblique to one another, so that as the nut is screwed down toward the holder Lits
conical surface approaches and bears against the side of the pencil. I thus form
an extremely simple and convenient fastening for the pencil by means of which it
can be quickly clamped or released and adjusted up or down at will.
The portion of the nut J which bears against the pencil is preferably made smooth
and conical in order not to cut or mar the pencil while being tightened against
it, and the remaining portion of the periphery of the nut is preferably milled or
roughened to facilitate turning it. These features however are not essential to my
invention.
Fig. 6 illustrates a modification wherein the compass leg is not adjustable in length.
The screw I which is formed either on the leg A' or on the holder L is screwed into
and brazed to the other part. I have here shown a modified shape of nut J which
will be understood at a glance.
Fig. 7 illustrates another modification wherein the compass leg is made longi-
tudinally adjustable but the set nut is dispensed with. The screw I is formed on
the leg A² and screws into a threaded hole in the holder L. The nut J is then
screwed down tight, which answers both for fastening the holder firmly to the screw
and for clamping the pencil or needle P firmly in place.
It will be apparent that this part of my invention is applicable to either one or both
legs of the compass and that it may be used for fastening a pencil, as shown in Figs. 1
and 6, or a needle point as shown in Fig. 7, or any other device to be used with the
compass. It is applicable to beam compasses as well as to those of the type shown.
It is by no means limited to spring compasses.
Having now particularly described and ascertained my said invention and in what
manner the same is to be performed, I declare that what I claim is :-
1. A compass, caliper or other analogous instrument having its hinge joint formed
with the pivotal ends of the legs on opposite sides of the hinge-axis, and clamped

page_text: between two washers, the legs being pivotally connected together by means of a
concentric annular rib on the washer entering a concentric groove in the legs, or vice
versa, substantially as set forth.
2. A compass, caliper or other analogous instrument, the pivotal ends of the legs
of which are formed entirely on opposite sides of a plane coincident with the hinge
axis, combined with a pintle passing between them, and heads or washers on opposite
sides united by said pintle and constructed with interfitting concentric annular ribs
and grooves formed on the legs and in one or both of said washers respectively,
substantially as set forth.
3. A compass, caliper, or other analogous instrument, the pivotal ends of the legs
of which are formed entirely on opposite sides of a plane coincident with the hinge
axis and having grooves a concentric with said axis, in combination with a washer
having an annular rib b entering said grooves, with a washer on the opposite side of
the legs, and a pintle passing through from side to side between the legs with its
opposite ends fixed to the respective washers, substantially as set forth.
4. A compass, caliper, or other analogous instrument, consisting of the combination
of legs A A formed with recess g on one side, and concentric grooves c on the
other, washer G formed with rib b entering said groove, washer F coming against
the opposite side of the legs and having boss entering said recess g, and pintle a,
substantially as described.
5. A compass, caliper, or other analogous instrument, the pivotal ends of the legs
of which are formed entirely on opposite sides of a plane coincident with the hinge
axis, cut away at ee and hinged together by means of washers on oppostie sides of
the head, and interfitting concentric annular ribs and grooves formed on the legs and
on one or both of said washers respectively, and combined with a cylindrically curved
leaf spring arranged to enclose the head, substantially as set forth.
6. In a compass the combination with the leg thereof of a pencil or needle holder
having a hole or socket to receive the pencil or needle, a screw arranged at an
acute angle to the axis of said socket and a clamping nut screwing on said screw
and adapted to bear against the exterior of the pencil or needle, substantially as
set forth.
7. In a compass the combination with the leg thereof of a pencil or needle holder
having a hole or socket to receive the pencil or needle, a screw arranged at an
acute angle to the axis of said socket and screwing into said leg or holder in order to
adjust the length of the leg, and a clamping nut screwing on said screw and adapted
to bear against the exterior of the pencil or needle, substantially as set forth.
8. In a compass the combination with the leg thereof of a pencil or needle holder
having a hole or socket to receive the pencil or needle, a screw fixed to said holder
at an acute angle to the axis of said socket and screwing into said leg in order to
adjust the length of the leg, a set nut on said screw to be tightened against said
leg and a clamping nut screwing on said screw and adapted to bear against the exterior
of the pencil or needle, substantially as set forth.
TL 11
141 1
הד
1000
J. C. MEWBURN,
169, Fleet Street, London,
Agent.