Improvements in Drawing Compasses or Dividers.
Year: 1896

page_text: Date of Application, 13th Aug., 1896
PROVISIONAL SPECIFICATION.
Improvements in Drawing Compasses or Dividers.
I, ALEXANDER JOSEPH GORMAND, of Florence Cottage, Great North Road, East
Finchley, in the County of London, Masseur and Medical Electrician, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in compasses and has mainly for its
object to provide a simple instrument whereby the centre of the distance between
any two given points can be obtained with great facility.
According to my invention I provide two legs of ordinary construction that is
to say similar to the legs of dividing compasses and pivoted at their upper ends
to one another or to a central head piece of suitable form and construction. To
each of these legs I pivotally attach a rack and I provide a pinion between the
legs adapted to engage with both the racks so that when the said rinion is rotated
by suitable means the legs open out. I also provide a third fixed leg passing
centrally between the two pivoted legs.
By this construction it will be obvious that when the pinion is rotated each leg
will be caused to recede to exactly the same distance from the central leg so that
to determine the centre between two given points the pinion is rotated until the
points of the two pivoted legs are coincident with the said points when the central
leg will indicate the middle point between the given points.
It will be obvious that the racks may, if desired, be made detachable or so as to
fold up against the legs.
In practice I find it advantageous to so arrange the central leg that its point can
be drawn above or below the points of the other legs, when desired, for instance
when applying the instrument to a convex or concave surface.
Dated this 13th day of August, 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
upro
ng Compasses or Dividers.
I, ALEXANDER JOSEPH GORMAND, of Florence Cottage, Great North Road, East
Finchley, in the County of London, Masseur and Medical Electrician, 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 improvements in compasses and has mainly for its

page_text: object to provide a simple instrument whereby the centre of the distance between
any two given points can be obtained with great facility.
According to my invention I provide two legs of ordinary construction, that is
to say similar to the legs of dividing compasses and pivoted at their upper ends
to one another or to a central head-piece of suitable form and construction. To
each of these legs I pivotally attach a rack and I provide a pinion between the
lege adapted to engage with both the racks so that when the said pinion is rotated
by suitable means the legs open out. I also provide a third leg passing centrally
between the two pivoted legs.
It will be obvious that the racks may, if desired, he made detachable or so as to
fold up against the legs.
In practice I find it advantageous to so arrange the central leg that its point can
be drawn above or below the points of the other legs, when desired, for instance
when applying the instrument to a convex or concave surface.
To enable my invention to be fully understood I will describe it by reference to
the accompanying drawing, in which:-
Figure 1 is an elevation of a pair of compasses made according to my invention:
Figure 2 is a section on the line 2-2 figure 1:
Figure 3 is a section on the line 3
figure 1:
Figure 4 is a section on the line 44 figure 3:
Figure 3 is an elevation of a modified construction of my improved instrument.
Figure 6 is a section on the line 6-6 figure 5, and
Figure 7 is a section on the line 7-7 figure 6.
a, a are the legs of the compass, the said legs being of ordinary construction,
and is the central head-piece to which the two legs a, a are pivoted at their
upper ends by means of the pins e, c. d, d are the racks pivoted at e, e to the
two legs a, a of the instrument, and f is the pinion arranged between the two
racks d, d. The pinion f is mounted upon the lower end of a central rod or
spindle 9 which extends through the head-piece of the instrument between the
two legs a, a and terminates at its upper end in a milled head by means of which
it can be rotated.
is the third leg extending centrally between the two legs a, a and through the
rod or g
spindle which is made hollow to receive it. The said leg i which is
provided with a head can be moved vertically so that it can be adjusted to the
same plane as the points of the legs a, a whatever their position when dividing a
line on a plane surface, or so that it can be pushed farther out or drawn farther in
than the said two points when employed on concave or convex surfaces. j is a guide
fixed to the central rod or spindle g, the said guide being designed to maintain
the racks d, d which pass through it, horizontal when the pinion f is rotated.
With this construction it will be obvious that when the pinion f is rotated each
leg a will be caused to recede to exactly the same distance from the central leg i so
that to determine the centre between two given points, the pinion f is rotated until
the points of the pivoted legs a, a are coincident with the said points when the
central leg i will indicate the middle point between the two given points, as the
said leg i bisects the angle formed by the two legs a, a,
The rod or spindle 9 can, if desired, be provided with a screw-thread working in
the head-piece so that it is screwed upwards as the legs a, a open out and vice
versa in order to rise and fall with the legs as they open out and close.
As above mentioned, the racks d, d may, if desired, be made detachable from the
guide or so that when the instrument is not in use, they can be folded up along
the legs a, a.
In figures 5, 6 and 7, I have illustrated a modified construction of my improved
instrument.
The legs a, a are pivoted at their upper ends to the central head-piece & in the
manner above described, but in lieu of the racks d, d I provide two arms or links k, k
pivoted at one end at e to the legs a, a similarly to the racks d, d and at the other
end to the lower end of the central rod or spindle g which in this case is screw-

page_text: threaded and passes up through the central head-piece b having an internal screw
thread to receive it. The central leg i passes down through the central rod gas in
the above described arrangement. In this case by rotating the milled head h of
the central rod or spindle g, the said rod or spindle moves upwards or downwards
in the central head-piece 6 so as to cause the two legs a, a to recede from or
approach the central leg in a similar manner to that above described with reference
to the preceding arrangement.
I will be obvious that by curving the legs a, a as in the case of calipers the
instrument can be used on curved surfaces. If desired the compass can be made
for receiving a pencil and pen similarly to an ordinary draughtsman's compass and
in the case of mechanics' compasses the central leg i can be formed as a drill.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. In drawing compasses or dividers the combination with the two pivoted legs
of a third leg and of means such as pivoted racks and a pinion or pivoted links
and a screwed spindle whereby the pivoted legs can he caused to recede simul-
taneously to an equal distance from the third leg, which therefore always bisects
the angle made by the two pivoted legs, substantially as, and for the purpose
hereinbefore described.
2. The improved drawing compasses or dividers hereinbefore described and
illustrated respectively in figures 1, 2, 3 and 4 and 5, 6 and 7 of the accompanying
drawings.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.