Method and Apparatus for Stamping or Marking Paper and other Thin Combustible Materials by the Aid of Heat.
Year: 1896

page_text: Date of Application, 23rd June, 1896-Accepted, 25th July, 1896
COMPLETE SPECIFICATION.
Method and Apparatus for Stamping or Marking Paper and other
Thin Combustible Materials by the Aid of Heat.
I, CHRISTIAEM CORNELIUS VAN DER VALK, of Haarlem, Holland, 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:-
Paper and other readily combustible thin materials have heretofore been marked
by impressing coloured stamps thereon. This description of stamping is subject to
several disadvantages. It is difficult to so regulate the quantity of colour applied
that the impressions are clear and dry. If too little colour is taken, the stamp is,
not sufficiently impressed; if too much colour is taken, the impression is liable to be
blurred or smudged; with fabrics having long fibres or of absorbent nature, the
colour is liable to spread, and thus render the impression indistinct. Lastly, coloured
impressions of stamps can be removed by washing and other processes.
My present invention has for its object, to employ for the marking of paper and
other thin readily combustible materials a method of branding by heated stamping
dies such as has hitherto been applied to wood, cork, leather and other materials
that are not so readily combustible, such method consisting in subjecting the parts.
of the material to be marked to the momentary action of a source of intense heat,:
whereby the stamp-dates and the like are burnt in a perfectly distinct manner into
the paper &c., without this being destroyed even at the points where it comes in
contact with the stamping die.
This improved process can, amongst other things, be advantageously employed.
for defacing postage and other stamps, and the like. In the method at present.
employed for this purpose consisting in stamping postage and other stamps by hand.
with black colour or ink, so as to deface them and prevent their repeated use, it is.
not impossible to remove the colouring matter by washing, chemical means or the
like, without damaging the postage stamp, so that this can then be used over again..
This possibility is not obviated by applying a thick coating of the colouring
matter, as even stamps so treated have been proved to be capable of being cleaned..
The use of excess of colour also has the disadvantage that the indications of the
date, the time of posting and of delivery, the indicating mark of the particular
post office &c. are rendered illegible, whereas the clear indication of these particulars
may sometimes be of the greatest importance.
In order to attain the desired object of defacing the postage stamps with perfect
certainty and at the same time to enable the indicating marks to be clearly
discernible, the use of black colouring matter, ink or other colours is according to
the present invention entirely done away with. In place hereof heat is employed.
for defacing stamps and marking the dates &c. thereon. This is effected by causing
a stamping die heated by means of any convenient source of heat, to remain for a
certain length of time upon the postage stamp &c. to be defaced or the envelope to
be marked, whereby the surface of the paper will be burnt or scorched at the
mpressed parts without damaging the contents of the envelope.
A combination of two stamps upon a disc can also be used in such manner that
the one stamp defaces the postage stamp while the other one marks the date on the.
envelope &c.

page_text: On the accompanying drawings are shewn various arrangements of apparatus for
stamping by means of heat, paper and other thin readily combustible materials
according to the above described process;
Figures 1 and 2 shew a sectional elevation and plan of an apparatus in which a
horizontally placed die holder a can turn round on an axis 6 carried in the
bearings cc of a frame d.
The rear end of the die holder carries an upright lever e against which act cams
on a revolving disc f, whereby the front end carrying the stamping die g is moved
downward so as to come in contact with a letter or other object inserted between.
the die and the support h. During such contact the stamping die will be burnt in
on the postage stamp, envelope, and the like, and immediately after the die holder
will be raised up again by the spring i, which may in some cases be replaced by &
balance weight.
The stroke of the die holder, that is, its lowest position, is regulated by the
adjusting screw n against which the lever e abuts. As soon as the stamping die has
reached its lowest position, the die holder springs upward again. By this means
the duration of the contact of the die with the object to be stamped is made to be
exactly the same during each stamping operation, and by correctly regulating such
duration, any excessive burning or scorching of the object is prevented.
The heating of the stamping die and holder is effected by means of a burner k.
combined with the holder, to which burner combustible gas is supplied through
the opening and the hollow part aº of the die holder, while the air supply enters
through the opening m. By this arrangement the heating flame will not be,
affected by the slower or quicker movement of the die holder. The die holder
and burner are surrounded by a metal casing which is not shown on the drawing,
and which can be isolated by a bad conductor of heat.
For changing the stamping die, the entire die holder is turned upward.
The cam disc f is rotated in the arrangement shewn by means of a worm
wheel o and a worm p. The latter can be either rotated by a hand wheel g, or by
a suitable motor by means of the cord pulley r, or by any other means.
Figure 3 shews a modification of the above described construction with
horizontal die holder in which by the rotation of a wheel a', a rod c¹ connected
to a crank pin & thereon has reciprocating motion imparted to it. At the forward
motion of the rod, a projection e, on the underside thereof, bears against the
upright lever f¹ of the die holder, which is, as before, combined with a.
burner g' and imparts to the stamping die at the front end thereof a downward
motion.
During the action of the rod on the die holder, its sloped front end slides upward
on a fixed incline d' which can be adjusted by a screw it.
By this means the projection of the rod c will be lifted away from the lever fi
and the die holder will spring upward again after a certain time as above described
under the action of a spring h.
Figure 4 shews the construction of an apparatus in which the die holder a² with
stamping die receives a vertical to and fro motion. The die holder moves freely
in a metal casing 2 isolated by a bad conductor of heat, and has a helical rib c
preferably cast thereon in order to utilise the heat supplied by the burner as much
as possible and to distribute it as uniformly as possible over the die holder. In the
lowest part of the casing is the burner d entirely surrounding the die holder
and its helical rib c³.
The die holder is guided by a plate e below the burner. This serves at the
same time to prevent soot or dirt from falling on the paper object under
operation.
The motion of the die holder is effected as follows. A worm on a shaft h³,
driven by bevil wheels and cord pulley, imparts motion to a worm wheel and
consequently to arms fixed on its shaft, k. The arms can be arranged singly
or in pairs.

page_text: Each of the arms, which are preferably provided with a roller, raises the die
holder during its revolution by acting on a plate m² on the latter. On the end of
an arm sliding off the plate m² the die holder does not fall directly upon the
stamp or envelope, but, in the first instance upon the heads of the levers n²,
mounted rotatably either singly or in pairs, upon the discharge tube d of the
fixed burner. A farther movement of the arms causes the next following arm,
which has a stud o, to raise the end of the lever p³ so as to turn lever n²
outwards, causing this to slide off the plate m², and to allow the die holder to
fall freely. A helical spring 92 draws the lever p² back again, and by means
of the adjusting screw the lever p² can be so adjusted that the impact of
the die holder and stamping die upon the envelope can be correspondingly
regulated.
The motion can of course be imparted to the die holder in any other suitable
manner such, for instance as by a pitch chain or a cord.
The die holder can be turned round on the rod g2 together with the casing and
burner, on loosening the screws f³.
A farther modification of the apparatus is shewn in elevation and plan at Figures 5
and 6.
In this arrangement the die holder, burner, and casing are arranged in the same
way as last described.
The upper end of the die holder a³ is provided with two rollers 63 63 situated one
over the other, between which rollers the elbow lever is engaged this being
pivotted on the upright, and having its second arm loaded with a counter
weight On this arm of the lever and also on the horizontal arm f³ are formed
opposite lugs g3 g to which are pivotted a pair of links pivotted together as
a toggle joint, and to this is connected a rod a pivotted at its other end to a lever /³
on a shaft to which a to and fro motion is imparted. In the motion thus
imparted to the links ha and h, the latter being pivotted to a fixed support 9,
the former is made to impart an up and down motion to the weighted arm of
lever c³, which is thus made to impart a corresponding motion to the die holder a³.
The shaft k³ can have its motion imparted to it either by hand or by a treadle, as
indicated by the dotted lines in Figure 5.
The heating of the die holder and die can in all the arrangements be effected
otherwise than by gas, for instance by electricity or by any other suitable heating
agent. The table on which objects to be stamped rest, is provided, at the part
where the stamping die acts, with a bad conductor of heat, such as asbestos
plates.
Figures 7 and 8 shew a construction of the stamping apparatus in which the
stamping or defacing is effected by means of a thin disc s which carries the dates
&c. in relief on its outer face, and which is intermittently heated by a flame
issuing from a nozzle do. The nozzle d is arranged so as to reciprocate in a
casing a the bottom of which is formed by the disc s; it receives its up and down
motion together with the casing a from a shaft to which is rotated by a crank
handle . On this shaft w arc fixed two arms and v of which the one v is
arranged within an oval ring and the other within an oval ring. These
rings and are carried by guide rods f" and fe which are connected to the
casing a and nozzle d by means of transverse rods q and qº.
Into the upper end of the nozzle d enters a gas pipe to which is carried by the
guide rod and moves up and down therewith. With the upper end of the
casing a is connected an air tube 15, which supplies the necessary air for producing
an intense heating flame. The air tube terminates at its other end in an air
bag 1, which on the rotation of the shaft to is compressed by a lateral pro-
jection of the arm to, and thus causes an air current to be propelled into the
casing a.
The casing a is provided with lateral openings o at its lower side, through
which the combustion gases can be discharged.

page_text: When the shaft w. is rotated the arms and 6 raise.the rings 6 and 7, whereby
the casing a and nozzle d' are raised. On the descent of the arms the casing a
and nozzle d descend to an extent proportionate to the thickness of the object to
be stamped and the stamping discs is applied to the latter. At the same time,
the projection compresses the air bag and causes an air current to flow into
the casing a which, in mixing with the gas flame issuing from the nozzle, forms a
flame jet which heats the discs to a high degree.
When the stamp, such as that shewn at Figure 10, has been burnt in on the
envelope &c., the farther rotation of the shaft to causes the casing a and
nozzle d to rise; the projection x liberates the air bag and the air supply
ceases.
If a stamping apparatus be used in which two discs such as so are combined, the
apparatus can be used in such manner, that at the downward motion of the discs,
the postage stamp &c. is defaced and at the same time the date stamp is burnt in
upon the envelope as indicated at Figure 13.
Figure 9 shews a modification of the stamping apparatus shewn at Figures 7.
and 8 in which the heating of the stamping disc is effected by means of an
electric current, in any well known manner.
The aim is for this purpose provided
with a contact piece which closes an electric circuit from a battery 6' as soon as
it makes contact with the ends of the circuit wires b6 b7.
is-
Figure 11 shews a modification of the stamping apparatus shewn at Figures 7
and 8, in which, in place of the solid disc with date &c. in relief a disc
employed, preferably formed of a bad conductor of heat in which the dates &c.
are formed by perforations. When this disc rests upon the object to be stamped,
the heating flame acts through the perforations of the discs directly upon the
object and thus burns or scorches the latter at the corresponding points; Figure 12
shews a stamp s produced in this manner.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. The method of stamping readily combustible materials, such as paper by means
of heat, cousisting in subjecting the parts of the said materials that are to be
marked with the stamp to the momentary action of intense heat, substantially-as
described.
2. The application of the method referred to in the first claim to the:
defacing of postage and other stamps, cheques and the like, substantially as
described.
3. Apparatus for carrying out the method of stamping referred to in the first
claim, consisting of a horizontally or vertically acting stamping die holder provided
with a heating device, which die holder is made to act with a limited stroke on the
object to be stamped and is then jerked away therefrom by the action of a spring,
counterweight, or the like, substantially as described with reference to Figures 1
to 6 of the drawings.
4. In stamping apparatus such as is referred to in the third claim, the use for
heating the stamping device of a gas nozzle d contained within a casing a carrying
a thin stamping discs, which casing is supplied with an air current during the
downward motion of the stamp and nozzle, so as to produce a flame jet that
will highly heat the stamping disc s súbstantially as described with reference to
Figures 7 and 8.
5. In stamping apparatus such as is referred to in the third claim, effecting the
heating of the stamping disc by means of an electric current, produced by causing
a contact piece e on a revolving shaft to to close a battery circuit on the descent of
the stamping disc, substantially as described with reference to Figure 9.
6. In stamping apparatus such as is referred to in the 4th and 5th claims,
substituting for the solid stamping disc sa disc se preferably of a bad conductor

page_text: of heat having the date &c. produced thereon by perforations through which the
source of heat is made to act directly upon the object to be stamped substantially
as described with reference to Figures 11 and 12.
Dated this 23rd day of June 1896.
ABEL & IMRAY,
Agents for the Applicant.