Improvements in Pneumatic Sheet or Paper Feeding Mechanism for Printing Machinery.
Year: 1893

page_text: Date of Application, 13th June, 1893-Accepted, 18th Nov. 1893
COMPLETE SPECIFICATION.
Improvements in Pneumatic Sheet or Paper Feeding Mechanism for
Printing Machinery.
I, JOHANN PETER LUHN, Manager of Printing Works, of 13 Johannisplatz,
Leipzig, in the Empire of Germany, 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, which is connected with printing machinery, relates to an
apparatus for automatically removing the sheets away from the pile into the
machine.
The main peculiarities of this apparatus centre in the arrangement that the
topmost sheet is not merely lifted off but also, by means of peculiar devices,
separated and removed from the sheets lying directly beneath it.
Suction and compressed air are employed to effect the foregoing, whilst besides
that there must also be regarded as of importance for the whole invention the
peculiar arrangements by means of which the various currents of air act on
the sheets, as well as the gradual lowering of the whole lifting off, separating and
conveying mechanism, corresponding to the diminution of the pile of paper, and also
the further conveyance on the carrying bands of ordinary quick acting presses.
The apparatus employed may be described in the following manner with
reference to the accompanying drawing, on which two forms of this apparatus are
shown:-
Above the table plate on which the pile of sheets is placed, the suction device F
is arranged. This latter consists of a plate with a suction bar F¹. The latter is
connected, by means of piping v, with an exhausting medium, which comes into
action at a given moment. The suction bar has various openings ¹, Figures 1, 3
and 4, which are in immediate contact with the uppermost sheet, and each separate
one of which may be closed by means of a slide 22 as soon as it is not needed owing
to the diminished size of the sheets.
The sheet suction device is adjustable up and down, and its movement in an
upward dnection is effected by means of. the eccentric or cam F2, and the pressure
bar F3 adjustable in the slot as for instance by means of a pin and nut engaging the
bar and slot. In addition to the sheet suction apparatus, a sheet separating device
is also employed, which removes from the sheet which has been drawn up by the
suction device any other sheets which may be adhering thereto, and which is done
by means of an air blast. For this object, a compressed air container J is applied
at the front edge of the table, which container is provided with openings at its
upper inner side, from which, at a given moment, the current of air emerges, which
passes between the two uppermost sheets and separates them one from another.
The size of these openings may be regulated according to the size of the sheets by
means of slides. The compressed air contamer J gradually descends in proportion
as the pile of paper diminishes. Further, in order to cause a reliable separation of
the two uppermost sheets, the topmost sheet is passed over a projecting edge y, in
such a way that the edge of the sheet of paper is bent somewhat downwards and the
current of compressed air from the container J can better pass between the two
topmost sheets.
The process, as herein before generally described, is carried out in the following
manner :-
Whilst the printing cylinder K makes one rotation, the eccentric or cam F*
makes one also. In the position shown in Figure 1, the lifting device rests on the
pile of paper, and sucks up the topmost sheet and then raises the same one sheet,
Figure 2, which is freed from any other sheets which may adhere thereto by the

page_text: current of air proceeding from the container J. The front edge of the sheet
is drawn under the projection y of the angle piece by the continued rising of the
suction device, the current of ai then pa-ses under the whole of the raised sheet
and bends the same on the plate F of the suction device. After the front edge of
the sheet has passed the front projection y, the sheet will pass between the
constantly rotating roller wl and the smooth upper surface of the container J, and
is thereby further transferred to the carrying bands which pass it forward.
By the diminution of the pile of paper, the sheet suction devices F F are very
gradually lowered, and in the same proportion the blowing and conveying devices
act on the front edge of the pile of paper at a lower level.
It also carries
The combined blowing and conveying apparatus, which stands at the front edge
of the pile of paper, is balanced by means of a counterweight (2) so that it may be
moved up and down without any great expenditure of force. As the pile of paper
becomes lower in height by the removal of the sheets one by one, the sheet-lifting
device descends by its own weight and by means of the springs (102) the pile of
paper each time is reduced by the removal of a sheet of paper.
downwards with it the blowing and conveying device to the same extent as this
latter is connected with the guide bar of the sheet suction device.
Arms may,
however, also be attached to the ends of the suction strips (bars), which, on the
descent of the sheet suction device, rest against the outer ends of the combined
blowing and conveying apparatus, so that the latter apparatus descends the
thickness of a sheet simultaneously with the sheet suction device. The latter may
also be moved downwards by means of a special arm w³ on the sheet suction device,
as shown in Figures 5 and 7.
The movement of the suction apparatus may, however, also be effected in the
manner shown in Figures 5-7, namely, the suction device being merely raised as
much as is necessary for releasing and placing the topmost sheet, that is to say,
the sheet table is raised in proportion as the pile of sheets diminishes. The
table B may be raised or lowered in the guides v³, and is pressed by means of a
weighted lever L, together with the pile of paper, against the contact piece L',
which is supported by a cross bar L' fixed on the frame. The contact piece Li
passes through a slot in the suction plate F, so that it is unhindered in its upward
movement.
On the other hand, the lever L rests on a conical roller M, which revolves with
the axis, and is adjustable on the same, so that the pressure of the lever may
be thereby limited or regulated according to the pile of sheets; this conical roller
is pressed by means of a spring w', Figure 6, against a conical roller N, which is
connected with the table by means of the lever bars m' m² m³, and consequently
descends in the same degree as the table rises, and vice versa. The conical
roller M is thereby adjusted in opposition to the pressure of the spring w, so that
it supports the lever L in such a way that the latter, in proportion as the pile of
paper diminishes, is transferred from the larger diameter of the cone roller M,
Figure 5, to the smaller diameter of the same, Figures 6 and 7, so that the end of
the lever which supports the table is raised in the same proportion. In order
that the sheet which is lifted may be drawn away under, L', the conical roller Mis
provided with a cam or projection n³, Figures 5 and 7, by means of which the
lever L is suitably drawn from the table B, and the latter is caused to sink.
If narrow sheets are to be worked on the apparatus, a suitable number of the
suction openings a¹ and also of the compressed air openings in the front edge y
are closed.
A side entrance for compressed air is also provided in addition, as shown in
Figure 3. The suction openings are partially closed, and the container R for
compressed air is inserted under the same, the openings 2 in which reservoir supply
compressed air sideways under the topmost sheet at the moment when the suction
device lifts the sheet. This compressed air has for its object to destroy the
vacuum which results at the moment when the sheet is separated from the one
beneath it.

page_text: Figures 5-7 show the apparatus in combination with a rotary printing press,
in which a gripping device is employed independent of the printing cylinder K,
which gripping device seizes the sheets and revolves with the printing cylinder.
In this case, also, the suction device raises one sheet until the latter has passed
the front edge of the projection y.
On the descent of the suction device, the front edge of the paper rests against
the front edge of the gripper bar D', Figure 5, and, on the further descent, the
front edge of the paper is pushed flat on to the bar D¹. When the lower face of
the sheet suction device has reached the same level as the gripper bar, the device
remains stationary in that position until the sheet has found a quiet resting place,
where it may be seized with certainty by the gripping device, and be further
transported by the conveying arms G.
This apparatus may be easily applied to any machine, because no essential
modifications of the presses in question need to be carried out.
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. A mechanism of the specified kind, in which the raising of the topmost sheet
of a pile is aided by means of a suction plate F, which is adjustable according to
the thickness of the pile, is always moved in a straight up and down line, and is
provided with closable suction openings, such raising being also performed in such
manner that air is blown under the topmost sheet from a container J of compressed
air arranged at the front edge of the pile of paper, and which descends with the
diminution in the thickness of the pile; and, finally, in which mechanism the
raised sheet passes away over an edge y, and then springs under a transporting
roller w', which conveys it further on the cessation of the action of the suction
apparatus.
2. An alternative form of construction of the mechanism specified in Claim 1,
in which compressed air may also be injected sideways under the topmost sheet,
by the arrangement, on both sides of the suction plate, of adjustable compressed
air receivers R', Figures 3 and 8, which may be suited to any size of paper,
substantially as described.
3. In a mechanisin of the kind specified in Claims 1 and 2, the modification in
which the suction plate has an unalterable movement, and the compressed air
reservoir is stationary, but, instead, the table B', with the pile of sheets on it, is
raised to correspond to the diminution in the latter by a weighted lever L, which
is supported on a conical roller M, being lowered by a gradual adjustment of the
roller, this adjustment being produced by a gradual lowering of the conical
roller N caused by the table itself by means of the lever m², substantially as
described.
Dated this 19th day of June 1893.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.