Year: 1888

page_text: Date of Application, 17th Mar., 1888
Complete Specification Left, 29th Nov., 1888
Complete Specification Accepted, 31st Dec, 1888
I JOSEPH HILARION BERGER of 47 Church Street Kensington, in the County of
Middlesex, Clerk in Holy Orders do hereby declare the nature of this invention to be
as follows:-
My Invention relates to improvements in proportional compasses whereby greater
and more permanent accuracy is ensured and whereby the instrument is rendered
serviceable for a greater variety of purposes.
My improvements have first for their object to render the proportion to which the
two members of the compass are set, more permanent that is to say to avoid the
derangement of the proportion to which existing forms of the instrument are liable
by frequent use in taking, and marking off, measurements. This improvement consists
in providing means whereby the binding screw on which the members work as a
pivotal centre, is relioved of the duty of maintaining the proportional adjustment of
said members, said binding screw serving only as the pivotal centre and for main-
taining the required stiffness of the joint. For this purpose I provide the usual slide
block of each member with an extension which inay be slotted and is securely
clamped by a binding screw to the member to which it appertains, whereby the pro-
portional adjustment of the slide block is permanently ensured, independently of the
pivotal binding screw.
My improvements have secondly for their object to enable the points of the legs to
be sharpened without altering their proportional relation to the graduation of the in-
strument. This improvement consists in fixing the points of the legs parallel to the
pivotal axis of the instrument (that is to say perpendicular to the length of the
instrument as in a beam compass). By this arrangement the instrument is not only
more accurate but is available for a much higher range of proportional adjustment.
The points of the one member would be fixed at a less radius than those of the other
member so as to pass within them both points of each pair being however flattened
at their adjacent surfaces so as to pass closely and make the working extremities of
the two points practically coincide in radius. For convenience of manufacture one

page_text: of the points may be adjustable radially, to enable this coincidence to be readily
obtained. As the flattened surfaces of the points would never be ground, the radius
of the points will not be altered by sharpening them.
The Invention further consists in providing the pivotal centre of the instrument
with a removable point axially, in line with such centre and on the same side of the
instrument as, and corresponding in length with, the points at the ends of the members
so as to be capable of use in conjunction therewith.
The Invention further consists in the combination with the instrument, of a
graduated arc affixed to the slide block of the one member so as to be for all propor-
tional adjustments of the instrument, concentric with the pivotal centre for use for the
purposes of a protractor in conjunction with the points above described and with an
index affixed to the slide block of the other member.
J. H. BERGER.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: Improvements in Proportional Compasses.
I, JOSEPH HILARION BERGER, of 47, Church Street, Kensington, in the County of
Middlesex, Clerk in Holy Orders, 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 :-
My Invention relates to improvements in proportional compasses whereby greater
and more permanent accuracy is assured and whereby the instrument is rendered
serviceable for a greater variety of purposes.
Reference is to be had to the accompanying drawings forming part of this specifica-
tion, wherein figure 1 is a plan view of the instrument opened out as in use and
figure 2 is an edge view of the legs being in line the one with the other. Figure 3
shews a detail of the adjustable working point, and figure 4 shews the centre point
removed.
The same letters of reference indicate like parts in all the figures.
My improvements have first for their object to render the proportion to which the
two members A B of the compass are set, more permanent, that is to say to avoid
the derangement of the proportion to which existing forus of the instrument are
liable by frequent use in taking and marking off measurements. This improvement
consists in providing means whereby the binding screw Con which the members work
as a pivotal centre, is relieved of the duty of maintaining the proportional adjust-
ment of said members, said binding screw serving only as the pivotal centre and for
maintaining the required stiffness of the joint. For this purpose, I provide the usual
slide blocks D (through which the pivotal centre passes and which fit in longitudinal
slots in the respective members, as usual) with extensions d which may be slotted to
perinit of the adjustment of the slide blocks and pivotal centre at various proportional
lengths along the members, and which are securely clamped by binding screws d'or
otherwise to the members to which they respectively appertain whereby the pro-
portional adjustment of the slide block is permanently ensured independently of the
pivotal binding screw.
My improvements have secondly for their object to onable the points of the legs
to be sharpened without altering their proportional relation to the graduation of the
instrument. This improvement consists in fixing the points a abb of the legs
parallel to the pivotal axis of the instrument (that is to say perpendicular to the plane
of the instrument). By this arrangement not only is more permanent accuracy
ensured notwithstanding wear of the points but equal accuracy is ensured for all
measurements within a greatly increased range whilst the instrument is available for
a much higher range of proportional adjustment, owing to the fact that the points are at all
positions of opening perpendicular to the paper. The one member B'would be shorter than
the other so that it and the points b b will pass between the points a a' of the other
member in order that the instrument may be opened in either direction. The points
are however flattened at their adjacent surfaces so as to make the working extremities

page_text: of tho two points of each pair a b or a practically coincide in radius. For con-
venience of manufacture one of the points may be adjustable radially to enable this
coincidence to be readily obtained. For this purpose the adjustable point I would be
carried by a sliding piece fitted in a groove in the end of the member B and secured
by a set screw passing through a slot in the sliding piece, as shewn in Figure 3. The
radius of the points will not be altered by grinding their rounded surfaces for the
purpose of sharpening them.
The Invention further consists in providing the pivotal centre of the instrument
with a removable point c (see figure 4) axially in line with such centre and on the
same side of the instrument as, and corresponding in length with, the pairs of
points ab, a, so as to be capable of use in conjunction therewith, for constructing
polygons and other like purposes. This point is formed by a screw pin screwing into
an axial hole tapped in the end of the centre pin C.
The Invention further consists in the combination with the instrument, of a
graduated are E affixed to the slide block of the one member B so as to be, for all
proportional adjustments of the instrument, concentric with the pivotal centre C for
use for the purposes of a protractor in conjunction with the points above described and
with an index F affixed to the slide block of the other member A. The arc E is
affixed to the underside of the slide block D of the member B by screws e and
passes around one side of the member B and is supported above the upper face of the
member A, as shown.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In a proportional compass, the combination with the slide blocks which carry
the pivotal centre of arms extending along the two main members of the compass and
secured thereto with provision for longitudinal adjustment, substantially as, and for
the purpose, specified.
2. A proportional compass, having the working points of the two members parallel
to the pivotal axis of the instrument, the points of the one member being adapted to pass
those of the other member, so that the instrument may be opened in either direction,
as, and for the purpose specified.
3. A proportional compass having the working points of the two members fixed
parallel to the pivotal axis of the instrument, those of the one member being adapted
to pass those of the other member, as described, one of said points being adjustable in
the direction of the length of the instrument, as, and for the purpose, specified.
4. In a proportional compass having the working points of the two members fixed
parallel to the pivotal axis of the instrument and adapted to pass each other, as
specified, the combination with the said working points of a central working point
fixed removably to the pivotal centre and on the same side of the instrument as the
end working points, substantially as specified.
5. In a proportional compass having the working points parallel to the pivotal
centre, and having a central working point as described, the combination with the
slide blocks which carry the pivotal centre, of an arc and pointer, substantially as
specified.
Dated this 29th day of November 1888.