IMPROVEMENTS IN SE " PERSPECTOGRAPHS OR INSTRUMENTS FOR RE-PRODUCING PICTURES PLANS DRAWINGS AND THE LIKE
Year: 1883

page_text: LETTERS PATENT to George Macaulay-Cruikshank of 135 Buchanan Street
Glasgow in the County of Lanark North Britain Patent Agent for an
Invention of "IMPROVEMENTS IN SE
"
PERSPECTOGRAPHS OR INSTRUMENTS FOR
RE-PRODUCING PICTURES PLANS DRAWINGS AND THE LIKE" communicated
to him from abroad by Hermann Ritter of Frankfort on the Main in the
Empire of Germany Architect
PROVISIONAL SPECIFICATION left by the said George Macaulay-
Cruikshank at the Office of the Commissioners of Patents on the
24th October 1883.
"
GEORGE MACAULAY-CRUIKSHANK of 135 Buchanan Street, Glasgow in the
County of Lanark, North Britain, Patent Agent "IMPROVEMENTS IN
" PERSPECTO-
GRAPHS OR INSTRUMENTS FOR RE-PRODUCING PICTURES PLANS DRAWINGS AND THE
LIKE A Communication to me from abroad by Hermann Ritter of Frankfort on
the Main, in the Empire of Germany, Architect
This Invention relates to improvements in "perspectographs" that is to say in
instruments or apparatus for re-producing in perspective or otherwise and to
varying scales according to the adjustment of the parts of the instrument pictures
drawings plans and the like. The improved instrument consists of two bars or
legs connected together at one end and towards their opposite ends, each centred
on a cross beam the width between the centres being capable of adjustment.
Between the point at which the bars or legs are connected together and the
centres on the cross beam the bars are further connected to a slide in another cross
beam or guide and on the said slide two bell crank levers are also centred both on
the same pin.
The arms of these bell cranks lovers are at right angles to each other and are of
equal lengths One arm of each lever being connected by a link the length of the
arm to a rod which in its turn is connected to one of the bars or logs first referred
ID 73

page_text: to. The other arm of each bell crank lever is connected to the centre of another
lever which in one extremity carries a pencil or other marker and at its other
extremity is centred on a pin. The distance from the said pin to the point of
attachment of the bell crank lever and from the said point of attachment to the
pencil or other marker is in each instance equal to the length of one arm of the 6
bell crank lever.
A pencil or point is also placed at the connection of the two bars or legs first
referred to and by tracing over the picture plan or drawing to be reproduced with
the said pencil or point the instrument is caused to reproduce the drawing by the
pencils or markers at the ends of the levers hereinbefore mentioned.
1

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Macaulay-Cruikshank in the Patent Office on the
23rd April 1884.
"
GEORGE MACAULAY-CRUIKSHANK of 135 Buchanan Street Glasgow, in the
County of Lanark North Britain, Patent Agent, "IMPROVEMENTS IN "PERSPECTO-
GRAPHS OR INSTRUMENTS FOR RE-PRODUCING PICTURES PLANS, DRAWINGS, AND THE
LIKE A communication to me from abroad by Hermann Ritter, of Frankfort-on-
the-Main, in the empire of Germany, Architect,
The said Invention relates to improvements in "perspectographs" that is to
say, in instruments or apparatus for re-producing in perspective or otherwise and
to varying scales according to the adjustment of the parts of the instrument,
pictures, drawings, plans, and the like
And in order that the said Invention may be properly understood I have
hereunto appended an explanatory sheet of drawings with reference to which I now
proceed more particularly to set forth the system, mode, or manner in or under
which it is or may be used or carried out in practice.
Of the said drawings figure 1, is a plan of the complete apparatus figure 2, is
an elevation of a portion of the front part thereof, figure 3, is an end elevation of
figure 2, figure 4, is an end elevation of the part of figure 1, immediately above it
and figures 5, 6, 7, 8, 9 10 and 11. are details drawn four times the size of the
corresponding parts of figure .
As shewn by these figures the instrument consists of two laths or bars A,
connected together at one end by a pin a, the lower part of which as seen at
figure 5, is formed into or has connected to it a point a³, which point in working
the instrument is guided by the hand over the line or contour of the figure it is
desired to re-produce.
A bracket consisting of two horns B, is centred to the under lath or bar A, by
the pin c, placed immediately behind the pin a, and on the said horns which
are preferably free to turn on the centre c, the forward ends of the lathes are
supported.
On both the upper and under sides of each lath or bar A, a channel or groove d,
is made into which are centred tongues e. These tongues are connected to and are
free to swivel through an arc horizontally in eyes C, D, E, F, The eye C, is secured
to a block, which is capable of adjustment in a groove j, made in the beam G;
and when adjusted to the proper position, of being fixed therein by means of the
pinching pin h, or its equivalent.
bar
The eye D, as seen in dotted lines at figure 1, is secured to the under side of a
9, which is slotted at each end so as to enable it to be secured at pleasure to
blocks i, i, placed in the groove j, and at opposite ends of the block f, the bar
being fixed to the desired block by a thumb nut k, or its equivalent whilst the
blocks themselves are capable of being secured in any desired position in the
groove j, by the pinching pins m, m', or their equivalents.
Parallel with the beam G, is another beam H, in a slot in which is situated a
sliding bar I, The eye E, is secured to the said bar, and the eye F, is adjustably
secured to a rod 2, carried on the bar by brackets n,
At or near the forward end of the sliding bar I, two bell crank levers J, are
centred on the same pin o, which is fixed unmovably in or on the bar I, The
arms J', of the levers J, are connected by pins p, p¹ to ends of bars or links K, the
other ends of the said bars or links being both centred on a pin q, which as more
particularly seen at figure 6, has a heel q', projecting downwards from it into a
guiding slot r, made in the sliding bar I, in which it is free to move, motion being
communicated by the heels 8 shewn enlarged at figures 7 and 8, carried on the
rod l, acting on the nut s' on the upper end of the pin q.
The arms J', of the bell crank levers J, are connected by pins t, t¹, to levers L, which
levers are also connected together by a pin u. At their free ends v, the levers L,

page_text: carry the pencils or markers by which is re-produced the picture, plan, drawing or
the like the lines of which are being traced by the point a², and such drawing
may either be reproduced in duplicate by both the pencils acting at once or a single
copy only may be made in which case the pencil carried by one lever L, is idle.
Figures 9, 10 and 11 shew in detal the method of carrying the pencils or
markers in the lovers L, 'As seen by these figures a tube v', to contain the pencil
is employed the said tube being preferably split at its lower end so as to afford a
grip on the pencil or marker and furnished with a screwed cap v³, as is well
understood. The tube v¹, is placed inside another tube w, which is screwed
externally and held in the lever L, by a palm formed near its lower end and by a
nut w, placed on the screwed part. Towards its upper end a disc y, is screwed on
to the tube v³, and from the said disc a pin y', projects downwards and enters a
hole or recess made in a disc x, secured on or formed on the upper end of a recl x¹,
placed loosely on the tube w, A weight 1, is placed on the disc y, which disc rests
on a bracket 2, secured to the lever L, and having one end of a spring 3, fixed to
it. To the other end of the spring a cord 4, is connected the said cord being also
connected to and partially wound round the reel x'. One end of another cord 5,
is likewise connected to and partially wound round the reel x¹, in a direction
opposite to the cord 4, In conjunction with the cords a cam 6, is formed on the disc y,
as seen at figure 10, and the action of the arrangement is such that when marking,
the pencil is held down to the paper by the weight 1, but when it is desired to
shift. the position without marking, the cord 5, is pulled which has the effect of
partially rotating the reel al, and with it the disc y, (the said disc and reel being
geared by the pin yl,) and the cam 6, coming against the upper part of the
bracket 2, the tube v', and with it the pencil or marker is raised the said pencil
being drawn down again on releasing the cord 5, by the spring 3, turning the reel
in the contrary direction.
It will be seen on reference to figure 1, that the distance between the point E,
and the point o, and between the point F, and the point q, is after adjustment and
in operating with the apparatus, constant, also that the angles to p, t'op', are
right angles and that the distance q p, q p² = 0 p, o p² = 0 t, o t¹ = t u,
t'u tv, t' v.
=
In adjusting the apparatus the distance between the fixed centres C, D, is
regulated according to the scale of perspective or other figure it is desired to
produce and for some purposes in order that the adjustment may be accurate it is
advantageous to provide scales as indicated at 8 figures 1, and 3.
Having now described and particularly ascertained the nature of the said
Invention as communicated to me I would observe in conclusion that what is
considered to be novel and original and is thereforo claimed as the Invention
secured to me by the herein before in part recited Letters Patent is,
First The perspectograph or instrument for re-producing pictures, plans,
drawings and the like constructed and arranged substantially as herein before
described with reference to the drawings annexed.
Second-In an instrument for re-producing pictures, plans, drawings, and the
like the arrangement and combination of the levers J, L, and links K, substantially
as described with reference to the appended drawings.
In Witness Whereof I, the said George Macaulay-Cruikshank have hereunto
set my hand and seal, this Twenty-second day of April in the year of our Lord
One thousand eight hundred and eighty four.