Note: Descriptions are shown in the official language in which they were submitted.
'_ 2193871
ELONGATED PRESS FOR PRESS MATERIAL MATS
The invention relates to elongated presses for the compressing
of press material mats, especially for the manufacture of wood
particle boards and for the vulcanization of conveyor belts.
Conventional presses of this type have upper and lower heated
press plates and a plurality of press frames which extend
therearound, are aligned in longitudinal direction of the
press and are connected to form a base frame. One of the
press plates is vertically reciprocatable by a plurality of
working cylinders which are positioned in the press frames.
The length of such presses is, for example, 15 to 20 m. If
the press is used for the manufacture of wood based materials,
it is provided with the conventional feeding and removal
arrangements for the press material mats and the finished
particle boards, for example, in the form of a continuous
transport belt which is guided through the press. A press for
the vulcanization of conveyor belts is constructed similarly.
In the conventional presses, the working cylinders are long
stroke cylinders. The stroke between the press plates which
is needed for feeding of the uncompressed materials and
removal of the pressed product is relatively short, for
example, 10 cm, and often only 10 mm are sufficient. This
would not require long stroke cylinders. However, for service
reasons a long stroke is required to move the press plates
sufficiently apart to allow full access thereto, for which the
long stroke cylinders are used. The service stroke is, for
example, 40 cm. The resulting costs for this hydraulic
arrangement are high.
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It is now an object of the present invention to provide a
simplified press of the above described type with a more
economical hydraulic arrangement and especially the working
cylinder arrangement.
This is achieved in accordance with the invention by using
working cylinders which are short stroke cylinders and the
pistons of which act on the movable press plate, the service
stroke being achieved by separate service cylinders provided
at the input and output ends of the movable press plate.
Accordingly, the invention provides an elongated press with
upper and lower heated press plates, a plurality of spaced
apart parallel press frames extending therearound which are
aligned in longitudinal direction of the press and are
connected to form a press base frame, a plurality of short
stroke working cylinders for vertically reciprocating at least
one of the press plates, the working cylinders being
positioned in the press frames and aligned in longitudinal and
transverse direction of the movable press plate, long stroke
service cylinders for reciprocating the movable press plate
from a working position to a service position and for locking
the plate therein, the service cylinders being positioned at
input and output ends of the movable press plate, which long
stroke cylinders are mounted to the press base frame. The
combination of the short stroke cylinders and long stroke
cylinders of the present invention replaces the corresponding
long stroke cylinder arrangements of the prior art. The
movable press plate can be moved into the service position in
several different ways as will be further discussed below.
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The long stroke cylinders can act directly or indirectly on
the movable press plate.
In a preferred embodiment, service cylinders are also provided
in the middle section of the press, for example, in such a way
that the length of the movable press plate is divided into
equal thirds, whereby the service cylinders are positioned
along the edge of the press plate. The movable press plate
can be locked in the service position in several different
ways. In the preferred embodiment, in accordance with the
invention, the service cylinders are combined with cylinder
operated lever systems with hooks for locking the movable
press plate in the service position. However, the movable
press plate, once in the service position, can also be locked
by supporting or spacer elements or locked by hydraulically
blocking movement of the long stroke cylinders after they have
lifted the upper press plate into the service position.
The movable press plate is preferably the upper press plate.
In one embodiment, wherein the upper press plate is vertically
reciprocatable, an upper, cylinder portion of each short
stroke working cylinder is rigidly affixed to an upper cross
beam of one of the press frames and a lower, piston portion of
the working cylinders acts on the upper press plate through
intermediate, interconnected, comb-shaped press force
transmitting spacer elements. The spacer elements are movably
guided in the respectively associated press frame and are
connected to a drive arrangement for displacement thereof in
longitudinal direction of the press and into the intermediate
space between the press frames and back into the press frames.
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The service position of the upper press plate thereby can be
reached when the force transmitting elements are in the
intermediate space allowing displacement of the movable press
plate for an additional distance corresponding to a height of
the spacer elements. In that embodiment, it is preferred to
use the above described lever systems.
In another embodiment, the short stroke working cylinders are
connected to cross beams which are vertically reciprocatable
in the press frames and on which the long stroke service
cylinders act, whereby the service cylinders are mounted
between the cross beam and the base frame. In that
embodiment, the service position can be adjusted by movement
of the cross beam.
In a further preferred embodiment, the lower press plate is
vertically reciprocatable, the short stroke working cylinders
are rigidly affixed with their lower, cylinder portion to a
lower cross beam of the press frames and the long stroke
service cylinders are connected to the upper cross beam of the
press frames. Interconnected comb-shaped press force
transmitting spacer elements are positioned between the upper
cross beam of the press frames and the upper press plate and
are connected to a drive arrangement for movement of the
spacer elements in longitudinal direction of the press from
under the cross beam into the intermediate space between the
press frames and back. The service position of the upper
press plate is adjustable by moving the spacer elements into
the intermediate space.
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The invention is based on the discovery that the construction
of the whole hydraulic system, including the working
cylinders, can be simplified when different cylinder
arrangements are used for the compression steps and for
service, which arrangements are specific for their function,
namely short stroke working cylinders for the pressing process
and long stroke service cylinders for the service tasks.
The invention will be further described in the following by
way of example only and with reference to the attached
drawings, wherein
Fig. 1 is a schematic side view of a press in accordance
with the invention;
Fig. 2 is a cross-section taken along line A-A in Fig. 1
with different construction in the right and left halves of
the drawing; and
Fig. 3 is a preferred embodiment of the press as shown in
Fig. 1.
The elongated press illustrated in Fig. 1 and 2 principally
consists of an upper press portion 1 and a lower press portion
2. A plurality of press frames 4 are provided which are
aligned in longitudinal direction of the press and are
interconnected to a press base frame 3. The press frames 4
are constructed of pressed sheet steel, whereby respectively
two sheet steel sections are placed opposite one another. The
press includes a heatable lower press plate 5 which is
stationary in the press frames 4 and a heated upper press
plate 6 which is vertically reciprocatable in the press
frames. The movable press plate 6 is provided with working
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- 6 --
cylinders in the form of short stroke cylinders 7 which are
aligned in longitudinal and transverse direction of the press
plate, which are otherwise connected to the press frames 4.
At the press material input and output ends of the movable
press plate, service cylinder arrangements are provided in the
form of long stroke cylinders 8 which are connected to the
press base frame 3. The movable press plate 6 can be moved by
way of the long stroke cylinders 8 to a sufficiently wide
service position in which it can be locked. In the preferred
embodiment of the invention as illustrated, the long stroke
service cylinders are also provided in the middle section of
the press, for example, in a manner which divides the length
of the press into equal thirds. The short stroke cylinders 7
can have a stroke of 10 cm and the long stroke cylinders a
stroke of about 40 cm.
It is apparent from Fig. 1 that the long stroke cylinders are
combined with lever systems 10 with hook shaped ends 11 which
are hydraulically operable by operating cylinders 9. With
these lever systems 10 the movable press plate can be locked
in the service position. This locked position by way of the
lever system 10 is illustrated in the right half of Fig. 2.
Upon comparison of Fig 1 with the left half of Fig. 2, it
becomes apparent that the upper, cylinder portion of the short
stroke cylinders 7 is rigidly affixed to the upper cross beam
12 of the press frame 4. The lower, piston portion of the
short stroke cylinders respectively acts on the upper press
plate 6 through intermediate, interconnected press force
transmitting spacer elements 13 which are comb shaped in side
view and which are guided in the respectively associated press
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frame 4. The spacer elements 13 are connected to a drive
arrangement 14 for displacement thereof in longitudinal
direction of the press. The elements are moved by the drive
arrangement 14 into the intermediate space 15 between the
press frames 4 and back into the press frames. The service
position of the upper press plate 6 is thereby achievable when
the spacer elements 13 are in the intermediate space 15.
In the press illustrated in Fig. 3, a lower, cylinder portion
of the short stroke cylinders 7 is rigidly affixed to the
lower cross beam of the press frames 4. The upper, piston
portion acts on the lower press plate 5. The service
cylinders 8 are connected to the upper cross beams 12 of the
press frames 4. Force transmitting spacer elements 13 are
provided between the upper cross beams 12 and the upper press
plate 6 and are connected to a drive arrangement 18. The
press force transmitting spacer elements 13 are displaceable
in longitudinal direction of the press by way of the drive
arrangement 18 and into the intermediate space 15 and back
into the press frames 4. The service position of the upper
press plate 6 is achieved by moving the press force
transmitting elements into the intermediate space 15.
