Improvements in, or connected with, Apparatus for Optical Projec- tion for Advertising and other Purposes.
Year: 1898

page_text: Reprinted
as amended in accordance with the decision of the Chief Examiner,
dated the 17th day of November 1899.
Improvements in, or connected with, Apparatus for Optical Projec-
tion for Advertising and other Purposes.
I, WALTER CLAYPOOLE, of Breadsall View, Otter Street, Derby, Derbyshire,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to a new or improved method for projecting upon a
screen, sketches, diagrams, writing, advertising devices and the like, in such a
manner that instead of the projected image appearing at once in its entirety as
with ordinary methods of projecting, it shall have the appearance of being
sketched in, the outline being the illuminated locus of a point. To effect this
I employ a pantograph or double parallelogram of jointed rods this device being
well known and of such a nature that the movements of a point which I will
call the tracing point may be correctly copied by another point which I will
call the graving point. The pantograph I employ gives a reversed reproduction
and conveniently to a smaller scale than the original copy. The tracing point
is moved over the outlines of the design to be projected, and simultaneously the
graving point moves over and in contact with, the surface of a glass plate pre-
viously placed in a lantern in the correct optical position for projection. The
surface of this plate I cover with a layer of some opaque and easily removeable
material such as soot so that the passage of the graving point leaves by the re-
moval of the soot, a narrow line through which light can pass. It will thus be seen
that the amount of the outline of the projected image which appears on the screen
depends on the amount of the outline of the copy which has been traversed by
the tracing point. In order that the graving point may be lifted from the surface
of the glass plate whenever the tracing point is lifted from the surface of the
copy I employ an electromagnetic device controlled by a contact conveniently
situated at or near the tracing point. I prefer to arrange this device so that
when an electric current of suitable strength is constantly supplied to the coils
of the electromagnet the graving point is kept constantly raised from the surface
of the glass plate, but if, by the agency of the aforesaid contact, the current
be diverted or shut off from the electro-magnet in any convenient way, the grav-
ing point is pressed into contact with the surface of the glass. I may use springs
conveniently arranged for assisting the electro-magnet to efficiently perform the
required movements.
In order to rapidly and easily transfer the design from the copy to the smoked
glass plate I prepare the copy on a flat surface of suitable material by somewhat

page_text: deeply grooving the outlines of the design in the substance. of the selected material
so that the tracing point may be rapidly and correctly guided along those lines.
Dated this Twenty-fifth day of January 1898.
Improvements in, or connected with, Apparatus for Optical Projec-
tion for Advertising and other Purposes.
I, WALTER CLAYPOOLE, 42, Otter Street, Derby, Electrical Engineer, 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 a new or improved method for projecting upon a screen
sketches, diagrams, writing, advertising devices and the like in such a manner that
instead of the projected image appearing at once in its entirety as with ordinary
methods of projection it shall have the appearance of being sketched in, the outline
being the illuminated locus of a point. To effect this I employ a pantograph or
copying machine; the form I prefer is well known and of such a construction as to
give a reversed reproduction of the copy, and conveniently to a smaller scale. That
point of the pantograph which is moved over the outlines of the copy I call the tracing
point, and that point which copies the movements of the tracing point I call the
graving point. The latter in the operation of the instrument is caused to move over
the surface of a transparent plate coated with an opaque and easily removeable
substance such as soot.
This plate may conveniently be made of glass and I will call it the smoked
glass plate. At the graving point is fixed a sharp needle which cuts through the
opaque film and engraves a narrow line through which light can pass. This smoked
glass plate is previously fixed in the optical system of a projection lantern in a similar
position to that which would be occupied by a transparency intended for projection.
It will now be evident to anyone familiar with the subject of optical projection that if
the tracing point be moved over the outline of any design whatsoever, a luminous
image of the same will appear on the screen, and the amount of such image visible
at any time will depend on the amount of the outline of the copy which has been
traversed by the tracing point.
In order to prevent any markings being made in the opaque film when it is not
desirable, or when the tracing point is lifted off the surface of the copy I employ an
electromagnetic device controlled by a contact situated at or near the tracing point.
I prefer to arrange this device so that when an electric current is constantly supplied
to the coils of the magnet, the graving needle is kept constantly raised from the
surface of the smoked glass plate, but if, by the agency of the aforesaid contact the
current be diverted or shut off from the coils of the electromagnet the graving needle
will be pressed on to the opaque film. I make use of springs to assist the electro
magnet to conveniently effect the desired movements.
I am aware that the idea of producing optical effects of the abovementioned nature
is not new, but my present invention embodies novel features of construction, and
possesses important advantages as will be hereinafter described.
In describing my invention reference will be had to the accompanying sheets of
drawings upon which
Fig. 1 is a diagram illustrating the type of pantogrenb emulaned

page_text: Fig. 2 18 to a larger scale than Fig. I and is a view of the electrical connections
between the electromagnet, pantograph, & control contact.
Fig. 3 is a side elevation to an enlarged scale of one type of control contact.
Fig. 3 is a plan view of the device shewn in Fig. 3.
Fig. 4 is a side elevation to the same scale of another type of control contact which
may be employed.
Fig. 4 is a plan of Fig. 4.
Fig. 5 is an elevation to the same scale, of the four pantograph arms at the graving
point end. These I call the graving links.
Fig. 6 is a front elevation to the same scale, of a portion of the metal plate or
frame which carries the electromagnetic device, and the pivot of the pantograph.
The graving links are here shewn in plan.
Fig. 7 is an elevation to the same scale, of the roller joint employed to guide the
midway points, such as X or Y of the long arms of the pantograph.
Fig. 7" is a plan of the joint shewn in Fig. 7 taken along the line 7' 72 and shows
the detailed contruction of the said roller joint and the method of supporting the
guiding ares to be afterwards described.
Fig. 8 is an elevation of the other face of the supporting plate shewn in Fig. 6 and
to the same scale. The figure illustrates the means employed to support and clamp
in position the smoked glass plate.
Fig. 9 is an end view of the plate shewn in Fig. 6 and Fig. 8 and further illustrates
the clamping device for the glass plate.
Fig. 10 is a diagram in plan showing the action of the clamping links and springs
represented in Figs. 8 and 9. The links are in the locking position.
Fig. 10 is the companion diagram to Fig. 10" and shows the position of the links
when the glass plate released.
Referring more particularly to these drawings. Fig. 1 represents in skeleton form
the type of pantograph I employ. The four arms between the points P and T are all
equal in length and are called for convenience the tracing links. The four arms
between the points P and G, are of a different length to those between P and T and
are also all equal in length, and are called the graving links. Those links of the
pantograph marked T.X. T.Y. X.P.B. and Y.P.A. are formed preferably of thin flat
steel bars, but the two arms A.G. and B.G. of the graving links are constructed in a
special manner to be afterwards described; see Fig. 5 and Fig. 6. The tracing
point T in Fig. 1 is, in the operation of the instrument guided over the lines of a
prepared copy fixed to the square drawing board D in Fig. 1.
At the graving point G is fixed a sharp Leedle g (see Figures 5 and 6) which
normally is kept just clear of the surface of a transparent plate preferably of glass
and having that face of it next to the graving needle covered with a thin coating of
some easily removable and opaque substance such as soot. This glass plate is seen
at S in Figs. 5 and and is supported in a metal plate or frame F which has an
opening or window arranged in it as shewn at W in Figs. 6 and 8. The glass plate
fits in a channel formed on the face of the metal plate in Fig. 8 by two fillets H
and 2 shewn in Figs. 8 and 9. The construction of these fillets is such that the
smoked surface of the glass is kept away from the face of the plate F so that the
opaque film will not be injured when the glass plate is placed in position. This
construction is seen in Fig. 9 where the glass plate is represented in position.
Referring to Fig. 6 at is a serew stud passing through the plate Fand serving as
a pivot round which the electromagnet. M M² may be slightly moved with a rotary
movement, its exact position being adjusted by means of the regulating screw K
acting in conjunction with the spiral spring L in a manner easily understood from
the drawing. This movement is to enable the graving needle to be easily and con-
veniently adjusted in position relatively to the smoked glass plate even while the
instrument is in operation. The advantage of this will he easily perceived.
Mechanical movement is transmitted from the armature of the electromagnet to the
graving needle by means of a flexible connection to be afterwards described. At p
(Fig. 6) is a stud screwed into the face of the plate F and forming a pivot around

page_text: which the pantograph can move. This pivot is shewn in elevation in Fig. 5; its
axis corresponds with the centre P (see Fig. 1) of the pantograph. I have not illus-
trated in my drawings the optical arrangements necessary to obtain a projected
image of the design which in the operation of my invention is engraved in the
opaque film. The centre of the window W in Figs. 6 and 8 lies on the optical axis
of the lantern system, and that portion of the glass plate opposite to the window W,
occupies a similar position to that which would be occupied by a transparency
in such a lantern. It is convenient to assign a maximum limit to the size of the
copy as shewn by the circle C¹ in Fig. 1, the engraved reproduction in the opaque
filin will therefore lie within the limits of a circle C.
Referring to Fig. 2, this figure in conjunction with either Fig. 3 or Fig. 4 illus
trates the electrical connections I employ in the working of the electromagnetic lifting
device for the graving needle, (shewn in Fig. 6). The coils M¹ M2 of the magnet I
connect to two terminals T and Te between which can be maintained, by connection
to a battery or other suitable source of electrical energy, an electromotive force of
suitable strength. The magnet coils being thus constantly supplied with a
current, the armature is constantly attracted, and by means of the flexible
connection y2 in Fig. 6 also seen in Fig. 5 the graving needle g is kept away from
the surface of the smoked glass. One of the abovementioned terminals say T¹ is
electrically connected with the metallic portion of the pantograph as shewn by
the wire. The other terminal 12 is connected by an insulated wire w² to a
flat flexible spring f¹ in Fig. 3 mounted on a non-conducting block J¹ fixed on one of
the pantograph arms near the tracing point. It will be seen that this spring is
normally electrically insulated from the pantograph but that it can easily be brought
.into electrical connection with the joint pin over which it projects by means of the
pressure of the operator's finger. The result of thus making contact is that the
terminals T1 and T2 are shunted by the extremely low resistance of the pantograph
arms and connecting wires and w². This operation causes practically the
whole of the current to be diverted from the coils of the magnet thus allowing
the armature to be released and the graving needle g to be pressed onto the
opaque film, by means to be afterwards described. I may employ in preference
to the above described contact, a semi-automatic type shewn in Fig. 4. In this
form, the joint pin has a hole passing axially through it in which a headed
pin d fits easily, its lower end projecting slightly through the nipple n². A
flexible spring of flat section is bent into a shape somewhat resembling the
letter C, and is fixed by its two free ends in some convenient manner to the head of
the joint pin t2 and so as to rest in contact with the head of the small pin d.
Immediately over the latter and just clear of the C-spring is an adjustable screw
contact e supported by a metallic bracket f2 fixed to a non-conducting block J. It
will now be seen that the act of pressing the tracing point on to the copy will push
the pin d inwards against the opposing pressure of the C-spring, and will cause the
latter to be brought into contact with the screw e. The bracket being connected
by an insulated wire to the terminal T2 as was the case with the spring in Fig. 3
the short circuiting of the magnet coils, and consequent release of the armature % is
accomplished in a similar manner as with the contact shewn in Fig. 3.
Referring to Fig. 5 which is an elevation of the graving links. For convenience
they are shewn on four adjacent planes, P being the centre line of the pivot of the
pantograph (see Fig. 1) and the centre lines A, G, and B, referrring to the same centres
as in Fig. 1. At the centres A, and B are two studs a and b fixed in the extremities
of the Hat steel pantograph arms. Their heads rest on raised facings E1 and E2
formed on the surface of the plate F and seen in plan in Fig. 6.
The facings are described about the centre P and their use is to serve to steady the
motion of the ends A and B of the long arms of the pantograph.
The stud at A carries a sleeve m which can move freely on the turned upper part n
of the stud. To this sleeve is pivoted one end of a thin steel arın ql at whose other
end is fixed a small tube h¹ which may be conveniently constructed of thin steel wire

page_text: wrapped to form a close spiral round a fine mandril. This tube serves to carry the
graving needle g which is driven tightly into it. The length of the link q¹ is so
chosen that the distance between the centres G and A is the same as that between the
centres A and P (Fig. 1). The other link to be described is that between centres B
and G. It is preferably constructed of a thin steel wire, well tempered, and having
helices and hs formed at either end. The helix 2 slips over the upper end of the
graving needle and the helix h³ fits on a pin fixed axially in the top of the stud
at centre B. The wire q2 is so bent as to produce a pressure on the graving needle
g
forcing it into contact with the smoked surface of the glass plate S, and its length is
such that the distance between the centres B and G is the same as between G and A.
Near that end of the link q¹ remote from the graving needle is fixed a stiff wire u pro-
jecting for a short distance perpendicularly above the edge of the link. From a hook
formed on the upper end of this wire a flexible connection is carried to the free
extremity of the armature of the electro-magnet, being guided around the centres
A and P, by means of the pins fixed at those centres. Since the flexible connection is
required to pass accurately from centre to centre, it is necessary to either cut a portion
of the pin away as at a¹ until the axis is reached, or else to cut a groove down to the
axis as at 2 in the pin at centre A. The flexible connection may conveniently
be a thin, silk ribbon as at y2 or a silk cord as at y¹. Both indeed may be employed
as represented in Fig. 5 and I may use other material to effect the same result.
It is
a great convenience in adjusting the graving needle with respect to the smoked glass
plate, to be able to vary the length of the flexible cord. This I accomplish by
attaching its lower end to a small pulley (Fig. 6) which fits loosely upon a stout
circular wire projecting from the free end of the ar.nature. This pulley being rotated
sufficiently to take up any desired amount of slack in the cord is secured in position
by the screw z¹. It will be seen on reference to Fig. 6 that the construction I employ
for the graving links q', and q² and for the support for the graving needle y is such
that only a very small amount of light is prevented from reaching the screen, by their
presence in front of the window W, so that the image of the links q' and q² is hardly
apparent on the screen. Referring to Figures 7 and 7a which are respectively an
elevation of that portion of the pantograph immediately around the centre X and a
plan taken along the line 72. These figures show the method I employ to guide
the centres X and Y. The object to be attained is to prevent the graving links being
disturbed by any movement imparted to the tracing point except such movement be
in the plane of the pantograph. To this end, the joint pin at X or Y has a circum-
ferential groove cut in it as at 1 Fig. 7 and projecting into this groove is the
convex edge of a thin metal are Q, the edge being part of a circle struck from
the centre P. There are two of these roller joints, one at each point X and Y, and two
metal arcs on which they run. These ares (Q) are conveniently supported on a single
arc N preferably constructed for lightness and rigidity of angle iron.
Fig. 8 is an elevation as seen from the lantern, of the plate F, and Fig. 9 is an end
view of the same. The use of the fillets H¹ and H2 has been described. In order to
clamp the glass plate S in position I employ a device comprising vertical spindles R¹
and R2, links U1, U2 and U³, and eccentric springs marked 3 and 3b. The spindles
R and R2 are parallel with and a little removed from the outer face of the glass plate S,
being supported in bearings V1 V2 V3 and V4, and connected at their upper ends by
links marked U1 U2 and 3 in a manner easily understood from the drawings. Towards
the middle of the spindles R1 and R2 are fixed clamping springs of a shape shewn in
Fig. 10.
This figure shows the position of the links when it is desired to secure the glass
plate S in position. It will be noticed that the springs which are made preferably
of thin flat steel such as clock spring, exert a firm yet resilient pressure on the
glass plate.
Fig. 10 shows the position of the links when thrown over to the other side
sufficiently far to cause the springs 3ª and 3 to come clear of the glass plate, thus
enabling it to be removed,

page_text: The disposition of the various parts which have now been particularly described,
is as follows:-
An open rectangular frame conveniently constructed of angle iron for lightness
and strength is used as a support to carry the various parts comprising the
complete apparatus; namely the drawing board D (Fig. 1) which is mounted on
one face of the frame and towards one end of it; a box acting as a receptacle to
hold the metal plate F and its attached accessories; and the circular are N (Fig. 7).
The receptacle box is mounted at or near that end of the supporting frame
remote from the drawing board, and the are N is mounted in an intermediate
position, determined by the radius P X or P Y (Fig. 1).
It must be observed that the board D should be on the same side of the supporting
frame as the lantern for "reflection " working and on the opposite side for
transparency" working.
66
By the former terin I mean the production of a correct image of the copy on the
screen when viewed from the same side that the apparatus in on. By the latter
term I mean the production of a correct image when seen from the other side of
the screen which must be translucent for the purpose.
Referring to the copy which is fixed to the drawing board D (Fig. 1). In order
to rapidly and easily transfer the design from this copy to the smoked glass plate, I
prepare the said design on a surface of suitable material by somewhat deeply
grooving the outlines of the design in the substance of such material. This forms
the copy and it will be evident that the tracing point may now be rapidly and
correctly guided along the grooved outline. My invention will however work
efficiently without any special grooving process being applied to the preparation of
the copy, this being merely to ensure rapidity of operation.
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. The improved-apparatus-substantially as described-and-illustrated for-optically
projecting outline sketches and-writing-upon-a-screen-in-such-away-that-the-image
shall-be-the-illuminated-locus-of-a-moving point:
1. The combination with an optical projection lantern of the improved apparatus
for simultaneously delineating and optically projecting a luminous image of a drawing,
writing, or other graphic matter on to a screen or surface in such manner that the
image shall be the illuminated locus of a moving point, constructed, operated, and
working substantially as described and illustrated.
2. The improved form of pantograph for transferring the lines of n-copy-en-to-u
prepared surfnee;-substantially-as-described.
2. The improved form of graving links enabling the graving needle to be lifted
away from or depressed on to the surface of the glass plate, without disturbing the
remaining portion of the pantograph, substantially as described.
4. The--electromagnetic device--neting in conjunction-with-n-controlling contnet,
together-with-the-necessary electrien!-connections-and-neting-for-the-purpose-of
lifting-the-graving needle--away--from-the-smoked--glass-plate, substantially as
described.
-The--mechanism for lifting graving needle-from, and adjusting its-position
relative-to-the--prepared-glass-surface, and--comprising the--flexible-connection,
device for altering-length-of-the-same, and adjusting serew-for-the-electromagnet,
all substantially-as-described.
6. The control-contact-of-the-mon-antomatic-type, worked by the-finger-of-the
operator, substantially as described.
8. In an apparatus of the kind hereinbefore referred to, the means for controlling
the graving instrument as regards bringing it in and out of contact with the graving
surface at will from the tracing point, consisting in the combination with the gracing
instrument of the spring gracing-link arm tending always to press the graving instru- 5
ment against the graving surface, the graving-link arm carrying the graving instrument

page_text: and pivoted so as to be capable of movement perpendicularly to the plane of the panto-
graph, the electro-magnetic device normally energised, the flexible connecting band or
piece mechanically connecting the armature of the muguet with said pivoted arm
normally holding the graving instrument out of contact with the graving surface, a
source of electric energy and the insulated contact fixed at or near the tracing point,
substantially as described and set forth.
4. In an apparatus of the kind hereinbefore referred to, the means for adjusting and
controlling the position of the graving-instrument relatively to the field of the graving
surface even while the instrument is in operation, consisting in the combination with the
flexible connecting piece and the electro-magnet, of a picot on which said magnet can
turn and means for adjusting the position of the magnet about said pivot, substantially
as described and illustrated in Figure 6 of the accompanying drawings.
5. In an apparatus of the kind hereinbefore referred to, the combination with the
pantograph, a source of electric energy and an electro-magnetic device having one
terminal electrically connected with or near the tracing point, of the spring-contact
electrically connected with the other terminal but insulated from the pantograph, sub-
stantially as and for the purpose described and illustrated in Figure 8 of the
accompanying drawings.
6. In an apparatus of the kind hereinbefore referred to, the combination with the
pantograph, a source of electric energy and an electro-magnetic device having one
terminal electrically connected with or near the tracing point, of the semi-automatic
insulated contact consisting of the adjustable contact stad, the loose tracing point and
spring normally pressing the said point outward adapted and arranged so that slight
pressure of the tracing point on the tracing surface causes the said spring to make
contact with the said adjustable contact stud, substantially as and for the purpose
described and illustrated in Figure 4 of the accompanying drawings.
7. The semi-automatic-control-contact;-substantially-us-described.
1000