Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention relates to conveying apparatus, especially
apparatus for conveying flat dough pieces.
During the mechanical manufacture of Arabic round flat loaves
(pitta), flat dough pieces to be baked are produced in such a manner
that severed and rounded dough portions are rolled flat by two rolling
mechanisms arranged at right angles to each other. During passage
through a first one of the rolling mechanisms the dough piece receives
an elongate oval shape which, during rolling transversely thereto in the
. . . . ..
second rolling mechanism, is converted into the desired circular shape.
For the purpose of these operations it is necessary to transfer the
pieces of dough from a conveyor path with the first rolling mechanism
-~ to a second conveyor path which extends at a right angle to the first
path and in which the second rolling mechanism is disposed. This transfer,
during which the shape of the dough pieces should not be changed,
- 15 entails problems because of the relatively soft nature of the dough.
One basically suitable form of angle transfer device is disclosed
in German (Federal Republic) patent specification No. 27 52 464, wherein
the end of the first cbnveyor path, usually formed by a conveyor belt,
extends obliquely upwards, from where the pieces of dough turn over in
a free fall onto the second conveyor path also formed by a conveyor belt.
In the case of dough pieces with diameters greater than about 250
millimetres and above all in the case of very thin dough pieces,
difficulties appear because a very high conveying speed is required for
complete turning over. The high conveying speed in turn requires a high
circumferential speed of the rollers of the first rolling mechanism, which
leads to impairment of the surface of the dough pieces.
Another kind of the angle transfer device for flat dough pieces by
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means of a reciprocatable deposit belt tongue is disclosed in German
(Federal Republic) patent specification No. 723 271, but is not suitable
for the manufacture of Arabic round ~lat loaves because the second convey-
or path must be virtually still during the deposit operation. The
intermittent conveying resulting therefrom is not acceptable due to the
second rolling operation taking place in the train of the second con-
veyor path.
In a baking oven loader described in German (Federal Republic)
patent specification No. 1 030 791, raisable and lowerable conveyor
chains are provided between the rollers of a main conveyor leading away
from the baking oven and form a transverse conveyor by which the
articles to be baked, which are disposed in containers, are conveyed
away laterally from the main conveyor. However, a chain conveyor cannot
be used for material as delicate as unbaked round flat dough pieces.
There is thus a need for conveying apparatus in which conveyed
items, including flat dough cakes of large diameter and small thickness,
can be transferred in careful manner between two conveying paths.
According to the present invention there is provided conveying
apparatus comprising means defining two conveying paths extending at
right angles to each other and transfer means disposed at a junction of
the paths for transfer of conveyed items from one path to the other and
comprising a plurality of conveying rollers arranged one after the
other to form a length portion of one of the paths and a plurality of
conveying belts arranged parallel to each other and in alternation with
and beside the rollers to form a length portion of the other path, the
plurality of rollers and the plurality of belts being upwardly and
downwardly movable relative to each other to effect transfer of conveyed
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items therebetween.
In the case of apparatus embodying the present invention, jerky
handling of dough pieces can be avoided, so that their shape and posi-tion
on the conveyor paths is maintained even during the transfer. Since the
transfer takes place qui-te independently of the speeds of the conveyor
paths, these speeds can be matched in optimum manner to the requirements
of any upstream or downstream treatment stations for the dough pieces,
for example rolling mechanisms.
Preferably the apparatus comprises sensing means to sense such
conveyed items and control said relative movement in dependence thereon.
By this measure, account can be taken of non-uniform succession of the
pieces of dough on the first conveyor path and a uniform positioning of
the dough pieces on the second conveyor path can be achieved.
An embodiment of the present invention will now be more particularly
described by way of example with reference to the accompanying drawings,
in which:
Fig. 1 is a plan view of part of apparatus embodying the invention,
- - in the region of the junction of two conveyor paths of
the apparatus;
Fig. 2 is a cross-section along the line II-II in Fig. l; and
Fig. 3 is an elevation of the apparatus in the direction of
arrow B in Fig. 1.
Referring now to the drawings, there is shown conveying apparatus
in which a first conveying path is defined by a feed conveyor belt 1 and
is arranged at right angles to a second conveying path defined by a
removal conveyor belt 2. Provided at a junction of the two paths in
continuation of the belt 1 is a succession of conveyor rollers 3, which
- 4 --
are mounted in a locally fixed frarne 4 only schematically sho~,m in Fig.
2 and have the same conveying direction and speed as the belt 1. This
conveying direction is indicated by an arrow A. The drive of the conveyor
rollers 3 is effected continuously by a chain drive (not showrl) which,
for example, acts on chain wheels 5 mounted at the ends of the rollers 3.
Provided directly in front of the removal conveyor belt 2 in the
conveying direction, denoted by an arrow B, of the second conveying path
is a group of parallel conveyor belts 6 which are guided over deflecting
rollers 7 and 8. The conveyor belts 6 move in the same direction and
at the same speed as the belt 2 and are driven by a motor (not shown)
which acts on the deflecting roller 8. The belts 6 are mounted by the
deflecting rollers 7 and 8 on a lifting frame 9, which is movable
vertically up and down and the movement of which, emanating from a lift-
ing device (not shown) is indicated by a double arrow H. A pneumatic
or hydraulic piston-cylinder unit or a mechanical crank or cam drive can
be provided as the lifting device.
As is evident from, in particular, Fig. 1, the belts 6 are guided
in such a manner by the deflecting rollers 7 and 8 that the conveyor
rollers 3 are arranged in alternation with the conveyor belts 6 so that
eacn roller is disposed alongside a respective one of the belts. The
conveyor belts 6 have such a small width that their upper sides in the
lower position, illustrated by solid lines in Figs. 2 and 3, of the
frame 9 lie underneath a horizontal plane tangential to the rollers 3.
In the upper position, illustrated by chain-dotted lines, of the frame
9 the upper sides of the belts 6 are disposed above the mentioned
horizontal plane and lie at the same height as the upper side of the
belt 2.
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In use of the apparatus, a dough piece T, which has been rolled flat
by a rolling mechanism (not shown) in the train of the first conveying
path and has the oval shape evident from Fig. 1, passes from the feed
belt 1 on to the group of conveyor rollers 3, at which time the lifting
S frame 9 with the conveyor belts 6 is disposed in the lower position.
The dough piece T is conveyed forward on the rollers 6 in direction of
the arrow A until it is disposed in the effective range of a sensor 10
arranged above the rollers 6 and preferably in the form of a capacitive
.
proximity switch. This sensor delivers a signal pulse to the lifting
device which then brings the lifting frame 9 into the upper position,
during which the dough piece T is lifted off the rollers 3 by the belts
6 and now moved on these belts in direction of the arrow B to the belt
2. The dough piece T is then move`d by the belt 2 to a further rolling
mechanism (not shown) on which it is rolled once again at a right angle
` to the first rolling direction and in that case brought into a circularly
round shape. After the transfer of the dough piece T onto the belt 2,
the lifting frame is automatically brought back into the lower position,
in which the device stands ready for the next transfer operation.
The same effect as described above can be achieved if, conversely
to the illustrated embodiment, the conveyor belts 6 are arranged in
locally fixed positions and the conveyor rollers 3 are movable up and
down. The effect is also the same if the belts 6 are associated with
the feed belt 1 and the rollers 3 with the removal belt 2.
