Improvements in Compasses, Dividers, and Calipers, or like Instruments.
Year: 1894

page_text: Date of Application, 31st Aug., 1894-Accepted, 20th Oct., 1894
COMPLETE SPECIFICATION.
Improvements in Compasses, Dividers, and Calipers, or like
Instruments.
1, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman do hereby declare the nature of this invention (which has been com-
municated to me from abroad by The Eagle Pencil Company of the City County
and State of New York, United States of America) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement:―
This invention has reference to compasses, dividers and calipers or like instru-
ments in which the legs are spread apart by a spring, and are closed by means
of a nut mounted on a vertical screw stem above the pivot on which the legs
move, and operating, usually through the intermediary of a sliding block, upon
extensions of the legs between which the block fits, the meeting faces of the block
and leg extensions being so formed as to cause the block, when pressed upon and
forced down between them, to close the legs together.
Dividers or calipers of this general type are old. The present invention consists
in a novel construction and arrangement of the parts whereby a very efficient
device of the kind is produced, of simple, compact and inexpensive construction.
The nature of the invention can best be explained and understood by reference
to the accompanying drawings illustrating the manner in which it can be performed
in which drawings
Figures 1 and 2 are elevations at right angles to each other of a device
embodying this invention.
Figure 3 is a section on the line 3-3 (Figure 2).
Figure 4 is a section on the line 4-4 (Figure 1).
Figure 5 shews the screw stem detached; and
Figure 6 shews one of the legs detached.
The legs A for the main part are of sheet metal and are formed each from a
sheet metal blank which is bent and swaged into the shape shewn in the drawings
(more particularly in Figure 6) so as to have the tubular portion a the ears 6 and
the trough like or concavo-convex flaring extension c above the ears b.
One of the legs is represented as provided with a metal point d which fits, and
is held, in the lower end of the leg. The other is provided with a split and spring
clasping sheet metal pencil holder e of any known or suitable construction, which
is set at an angle to the leg so as to permit the convenient insertion of the pencil P
and to allow the head of that pencil to pass through and extend up beyond or in
the rear of the holder without interfering with or abutting against the head of
the instrument.
This arrangement is convenient, but in lieu of it the ends or points of the legs
may be of any suitable or desired kind.
The legs are held together by a pivot pin f which passes through the ears b
the latter being perforated and being put together so that the holes in them will
register and thus permit the passage of the pin which is then secured in place by
rivetting down its ends or in any other suitable way.
Before the pin fis inserted the perforated end of a screw B is inserted between
the ears with its holes in register with those in the said ears so that the same
pin f will hold all the parts together. This end of the screw is slotted as shewn
at g and through the slot g, above the pivot passes the bight of a bent spring h
the outer and free ends of which pass down into and are housed in the tubular
legs A, and bear outwardly against the same. The spring his inserted in place in

page_text: the legs, when the ears of the latter are brought together, but before the screw B
is placed between the ears or the pivot pin is inserted. After the spring is thus
put in place, the screw B is fitted between the ears, its slotted end straddling the
bight of the spring, and then when the holes in the ears b and the end of the
screw are brought in register, all parts are secured in place by the pivot pin f
The spring at its centre or bight is held in the space between the pivot pin f and
the top of the slot 9 in the screw, its ends are completely housed by the legs into
which they extend.
Upon the screw stem is mounted a nut C which engages the thread on the
screw B and is the means by which the legs A are closed against the stress of
their spring h. The spreading action is attained by means of a block D loosely
encircling and capable of free movement in both directions on the screw stem B.
The ends of this block D fit and are held in the concave extensions c which thus
serve to guide the block and prevent it from turning or getting out of place, and
the meeting faces of the block and the extension are so formed as shewn that,
when by the nut C, the block D is forced down between the extensions c the
latter will be spread apart, with the effect of course, of closing the legs A
together.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. In dividers or calipers or like instruments the pivoted legs formed with the
concave extensions c in combination with the screw stem B the nut c, the sliding
block D, extending between and fitting and held at its ends to the said concave
extensions, and the spring, as hereinbefore described and illustrated.
2. In dividers or calipers or like instruments the sheet-metal legs formed with
tubular parts a, ears and concave extensions c, in combination with the screw
stem having the slotted end g, the nut C and the block D, the pivot pin by which
the legs and screw stem are held together, and the spring h, passing through the
slotted end of the screw stem-above the pivot pin, and having its free ends
downwardly extending and housed in the legs, as hereinbefore shown and
described.
3. In dividers or calipers or like instruments the tubular legs, the screw-stem
having the slotted end 9 and the pivot pin by which the said stem and legs are
secured together in combination with the spring having its bight contained in the
slotted end of the screw stem above the pivot pin, and its free downwardly
extending legs housed in the tubular legs, substantially as herein before shown and
described.
Dated the 31st day of August 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, W.C., Agents.