Improvements in the Method of and Apparatus for Stamping Sheet Metal and the like.
Year: 1898

page_text: PROVIDIONAL DREIFICATION.
Improvements in the Method of and Apparatus for Stamping Sheet
Metal and the like.
1, LUCIEN LIAIS, of 15, Rue de Normandie, Courbevoie, near Paris, France,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has reference to stamping sheet metal, tin plate and the like
cold.
In order to render my invention and its advantages understood I will first ex-
plain the stamping processes now actually in use. The machines hitherto usually
employed for this purpose comprise a fixed matrix, a movable part which grips
the blank, and a stamp or plunger. The function of the blank gripping device
is to maintain the blank to be stamped in continuous contact with the matrix
while the stamp forces it into the matrix. The gripping device has the further
object of preventing buckling of the blank and of maintaining it always of the
same thickness.
This method of working has a double inconvenience.
1. By always maintaining the blank to be stamped at the same thickness the
material under treatment becomes torn or weakened.
II. There is produced at the edge of the matrix a very considerable tangential
horizontal strain which in practice renders the operation difficult and occasions
a serious waste.
The main object of the present invention is to remedy these two evils, that is
to say, prevent the laminating action between the matrix and the blank gripping
device upon the material to be stamped, by doing away with, or at least reducing,
the tangential strain existing when the material is forced down over the edge of
the matrix.
According to my invention I overcome the first of these drawbacks by allowing
the blank holding device to rise progressively to a small extent in proportion as
the stamp forces the material into the matrix. The result of this is that the thick-
ness of the blank to be stamped increases from the centre to the periphery. This
increase of thickness should take place in such manner that the surface of the
blank remains perfectly smooth and presents no buckling. To this end there
should be imparted to the blank gripping device a rise which is proportional to
the thickness of the material to be treated.
The sides of the object thus obtained however would present the serious draw-
back that their thickness would increase from their base to the extreme edge. In
order to obviate this defect I adopt the following means. The edges of the matrix
have a slightly elliptical form and terminate as an arc of a circle in such a manner
that at the point from which the said are springs the diameter of the matrix is
equal to the diameter of the stamp plus twice the thickness which it is desired
to give to the material. As the stamp descends there is thus produced at the

page_text: said point a laminating action which operates vertically in the matrix and permits
the material to pass readily into the matrix, bringing it again to its original thick-
ness. In this way all tearing of the material to be treated is avoided.
I will describe my invention as applied to a toggle stamping press such as those
now commonly employed.
In order to effect the raising of the blank gripping device in such toggle presses
I adopt the following:
to.
The crank shaft of the machine carries at its extremity a crank which imparts
motion to a slide block which always moves in a slideway; the result is a vertical
displacement of the stamp which communicates its movement to two levers which
impart a movement of partial rotation to two shafts. These shafts operate the
part carrying the blank gripping device through the intermediation of suitable
levers. The blank gripping device thus receives a vertical movement but in con-
sequence of the arrangement of the levers comes to rest for a moment at the top
and bottom of its travel this rest being due to the crank arriving at its dead point
at each end of its throw in the manner usual in presses of the construction referred
Now in order to produce the progressive rise of the part carrying the blank
gripping device, as above indicated, this must not remain motionless at the bottom
of its travel, but must be adapted to again rise a determined distance to allow
the material to pass. To obtain this result I form the upper part of the slideway
above referred to with a slope, the height of which at its highest part is calculated
proportionally to the displacement which the blank gripping device should have.
It will be readily understood that by reason of this slope the pressure will pro-
gressively diminish, producing the desired slackening or releasing motion, while
the slide block will act upon the upper part of the slideway in which it works
In short there will be first complete gripping of the blank by the blank holding
device when the slide block begins to act upon the upper portion of the slideway,
then a progressive rise of the blank holding device until the slide block leaves ilie
upper portion of the slideway, this progressive rise being produced by the
difference of level existing between the respective ends of the slideway.
This releasing action is produced until the slide block bears against the lower
part of the slideway to cause the blank gripping device to rise completely.
In order to diminish the wear on the parts of the machine and the slideway I
interpose between the carrier of the blank gripping device and the nuts which
secure this carrier to the threaded bolts forming the connection with the levers
operating the carrier, springs formed of two concave washers of truncated cone
shape superposed base to base; this arrangement permits of allowing materials
of unequal thickness to pass.
When it is desired to form articles of greater depth the reducing stamps and
matrices such as are generally used are employed while adopting the arrange-
ment of machine and matrices above described.
Dated this 9th day of September 1898.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
Improvements in the Method of and Apparatus for Stamping Sheet
Metal and the like,
I, LUCIEN LIAIS, of 15, Rue de Normandie. Courbevoie, near Paris, France,"
Engineer, do hereby declare the nature of this invention, and in what manner

page_text: the same is to be performed to be particularly described and ascertained in
and by the following statement:—
This invention has reference to stamping sheet metal, tin plate and the like
cold.
In order to render my invention and its advantages understood I will first ex-
plain the stamping processes now actually in use with reference to Fig. 1 of the
accompanying drawings. The machines hitherto usually employed for this pur-
pose comprise a fixed matrix A, a movable part B which grips the blank, and a
tool or plunger C. The function of the blank gripping device is to maintain
the blank to be acted on in continuous contact with the matrix A, while the.
tool C forces it into the matrix. The gripping device has the further object of
preventing buckling of the blank and of maintaining it always of the same thick-
ness.
This method of working has a double inconvenience.
I. By always maintaining the blank at the same thickness the material under
treatment becomes torn or weakened.
II. There is produced at the edges f f of the matrix A a very considerable
tangential horizontal strain which in practice renders the operation difficult
and occasions considerable waste.
The main object of the present invention is to remedy these two evils, that is
to say, to prevent the faminating or stretching action between the matrix and the
blank gripping device upon the material to be stamped, by doing away with, or
at least reducing the tangential strain existing when the material is forced
down over the edge of the matrix.
According to my invention I overcome the first of these drawbacks by allowing
the blank holding device B to rise progressively to a small extent in propor-
tion as the tool C forces the material into the matrix A. The result of this is
that the thickness of the blank increases from the centre to the periphery as
indicated in Fig. 2. This increase of thickness should take place in such manner
that the surface of the blank remains perfectly smooth and presents no buckling.
To this end there should be imparted to the blank gripping device a rise which
is proportional to the thickness of the material to be treated.
The sides of the object thus obtained however would present the serious draw-
back that their thickness would increase from their base to the extreme outer
edges as indicated in Fig. 3. In order to obviate this defect I adopt the
following means. I make the edges of the matrix A of a slightly elliptical form
and thus terminate in an arc of a circle, at the point f (Figure 2) in such a
manner that at this point the diameter of the matrix A is equal to the diameter
of the tool C plus twice the thickness which it is desired to give to the materia!.
As the tool Ĉ descends there is thus produced at the point f a laminating or
stretching action which operates vertically in the matrix and permits the
material to pass readily into the matrix, bringing it again to its original thick-
ness. In this way all tearing of the material under treatment is avoided.
I will describe my invention as applied to a toggle press such as those now
commonly employed. In this connection reference is to be had to Figs. 4 and 5,
which are respectively a side elevation and a front end. elevation of a press of
this kind.
The crank shaft a of the machine carries at its extremity a crank c which
imparts motion to a slide block D which always moves in a slideway 9 formed in
or fixed to the sleeve O which sleeve is capable of a vertical reciprocating inove-
ment upon a bar 0. The movement of the crank c is thus transmitted through
the slide block D to the sleeve O while the slide block D always works in its
slideway g. The movement of the sleeve O is communicated to two pairs, of
levers which are fulcrummed at m, m, and which impart a movement of
partial rotation to two shafts o o. These shafts operate the part 13* carrying the
blank gripping device B through the intermediation of suitable levers ¹. The

page_text: blank gripping device B thus receives a vertical reciprocating movement but in
consequence of the arrangement of the levers, comes to rest for a moment at the
top and bottom of its travel this rest being due to the crank arriving at its dead
point at each end of its throw in the manner usual in presses of the construction
referred to.
Now in order to produce the progressive rise of the part B* carrying the blank
gripping device B as above indicated, the said part must not remain motionless
at the bottom of its travel, but must be adapted to again rise a determined dis-
tance to allow the material to pass. To obtain this result I form the upper part v
of the slideway above referred to with a slope y y¹ (Fig. 6), the height of
which at its highest part y is calculated proportionally to the amount of rise
which the blank gripping device B should have.
The effect of this slope in the slideway 9 in allowing of a gradual and pro-
gressive rise of the blank gripping device as the stamping action proceeds, will
be understood from the following description and the diagrammatic drawings
Figs. 8, 9 and 10.
I will in the first place explain what would occur if the slideway instead of
being inclined were horizontal. This is shown diagrammatically in Fig. 8. It
will be seen that in this position of the parts the blank gripping device B is com-
pletely raised and the sleeve O on the contrary is at its lowest point of travel.
Passing now to Fig. 9 in which the full lines show the position of the parts at
the commencement of the stamping action and the dotted lines the position of
the parts towards the end of the descent of the stamp plunger and supposing the
slideway to be horizontal, it will be observed that at the commencement of the
stamping the lever t occupies a position which is not horizontal, and which cor-
responds exactly with the commencement of the bearing of the blank gripping
device B upon the blank to be stamped, its length being calculated with this
object. During the rotation of the driving shaft, represented in Fig. 9 by the
point a, the sleeve U rises and towards the end of the stamping operation
occupies a position corresponding to that shown in dotted lines. The lever t
will then have risen and at its extreme position will have passed through an angle
which we will call a. The arc m m will have been described without the
position of the levers being changed, and in this case the pressure of the
blank gripping device upon the blank will remain constant.
Let us now see what will occur if the slideway y y¹ be inclined, see Fig. 10,
in which the inclination of the upper face of the slideway is exaggerated for the
sake of clearness.
In this case, at the commencement of the stamping operation, the slide block 1)
maintains the sleeve O in the position indicated in full lines; the crank cof
the slide-block describing an arc, occupies towards the end of the stamping
operation the position shown in dotted lines. It is during this operation that the
slope of the slideway acts. In fact, in order to allow of a progressive rise of the
blank gripping device it is necessary 1st. to counteract the rise produced by the
motion of the crank, that is to say to depress the sleeve 0 a distance equal to a
(Fig. 10) height of the arc described by the crank, 2nd to increase this quantity a*
by a quantity proportional to the thickness assumed by the metal. Therefore
calling the distance between the horizontal and the inclined slideway 6 it is
necessary to have b) a*. In this position the point m will have again descended
to m (by reason of the increase of thickness assumed by the metal and by the
weight of the sleeve O), and the lever t will have acted on the levert to
slightly incline it, this producing a slight rise of the blank gripping device in-
dicated in c Fig. 10 and the position of the parts has become that shown in dotted
lines in Fig. 10.
It may here be stated that the slope to be given to the slideway is the
function of two quantities which can be always varied.-1st. the length of. the
lever t, 2nd. the length of the crank of the slideblock D applied at a.
It will be thus understood that by reason of the slope in the slideway the pres-

page_text: sure on the blank will progressively diminish during the stamping operation,
producing the desired slackening or releasing movement, the slideblock D during
the descent of the stamp always acting upon the upper part of the slideway
and moving in the slideway from left to right. During the descent of the tool C
to effect the stamping operation; the action is as follows. When the blank
gripping device is at the lowest point of its travel (Fig. 6) the slide block D is
at the left of the slideway g; the blank gripping device B exerts its pressure
upon the blank and the slide block D is forced against the top bearing surface
of the slideway at the lowest end thereof.
When the tool C has effected half of its stroke the blank gripping device has
risen to a slight extent because the slide block D is now at the middle of its
travel in the slide way. It therefore bears upon a higher part of the slope y y'
and there is therefore a slight play between the slide block and the bottom of the
slideway. The blank gripping device remains in contact with the blank, because
the molecules of the metal of the blank have the continual tendency to be driven
radially from centre to periphery of the blank and consequently the thickness
of the blank tends to increase from the commencement to the end of the stamping
operation. This increase of thickness of the metal remaining beneath the
blank gripping device, that is to say, not yet stamped is allowed to take place by
the slight progressive rise of the blank gripping device; wedging of the metal
between the top of the matrix and the blank gripping device is thus obviated.
As the tool C continues to descend the slide block D moves to the right of g,
finally it reaches the highest portion of its travel in the slideway g, the thickness
of the extreme edge of the blank is now greater than any other portion of the
blank which has passed into the die, but this is reduced to the common thickness
by the drawing action exerted between the tool and the die.
This releasing action is continued until the slide block D bears against the
lower part of the slideway to cause the blank gripping device 13 to rise com-
pletely.
In order to diminish the wear on the parts of the machine and the slideway 9
I interpose between the carrier B of the blank gripping device B and the nuts i
which secure this carrier to the threaded bolts forming the connection with the
levers operating the carrier, springs k formed of two concave washers of truncated
cone shape superposed base to base as shown in Fig. 7; this arrangement allows
materials of unequal thickness to pass.
When it is desired to form articles of greater depth reducing tools and
matrices such as are generally used are employed while adopting the arrangement
of machine and matrices above described.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:
3
1. The method of stamping tinplate or other metals in presses which consists
in causing the plunger or tool to descend into the matrix without producing
drawing or stretching of the material between the matrix and the blank gripping
device, by causing the latter to rise progressively in proportion as the material
enters the matrix, whereby the portion of the blank comprised between the
matrix and the blank gripping device is caused to increase in thickness substan-
tially as herein before.
2. For carrying out the method specified in the previous claim, the construction
and arrangement of the plunger or tool and matrix between which the material
is brought again to its original thickness in consequence of the pressure to which
it is subjected between the tool and the internal portion of the matrix substan-
tially as described and shown in the accompanying drawings.
3. In toggle presses, constructing the upper portion of the slideway with a
lpe adapted to allow a very small progressive rise of the blank gripping device
while the blank is being acted upon in such manner that the metal is not drawn

page_text: or stretched between the matrix and the blank gripping device, and is thickened
towards the edges, substantially as described and shown.
4. In the toggle presses referred to in the last preceding claim the use of com-
pression springs of truncated cone shape, to regulate the pressure of the blank
gripping device substantially as described and shown and more particularly with
reference to Fig. 7 of the accompanying drawings.
Dated this fith day of January 1899
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.