Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to an apparatus for
pulling-off the skin of sheep carcasses in connection with
slaughtering, comprising an essentially horizontal drum which
is arranged to pull off the skin cluring winding thereof on
the drum, the drum being moved along the dorsal side of a
sheep carcass.
In connection with slaughtering of big cattle there
is known devices for pulling-off of hides wherein a drum is ar-
ranged to pull off the hide during simultaneous winding thereof
on the arum. However, the known devices are not practically
usable for pulling-off of skins in sheep slaughtering, as they
do not provide for the necessary and appropriate distribution
of the pressure on the skin and the sheep carcass around the
whole carcass, with the result that the carcass cracks on ex-
posed places, and the membrane which is to remain on the car-
cass is pulled off together with the skin.
The object of the invention is to provide an apparatusfor pulling-off skins of small cattle carcasses, especially
sheep and lamb carcasses, by which there is achieved a rational
and effective puiling-off of skins, and wherein the drum is
especially shaped in order to achieve reduced working effort
by flaying and simultaneously ensure .gentle skin pulling-off
without damage of the carcass.
. For the achievement of the above-mentioned object
there is provided an apparatus of the type set forth above, which,
according to the invention, is characterized in that the drum
has a gradually increasing diameter from a central portion to-
wards both ends, and is mounted at the free end of a pivotable
beam which is provided with a means for pivoting movement of the
beam during the pulling-off operation, and that there is pro-
vided a means for rotation of the drum synchronously with thepivoting movement of the beam and with a speed which is adapted
to the movement of the beam.
In a further aspect of the present invention, there
is provided an apparatus as described immediately above, wherein
the drum is moved in an upwards direction during the pulling-
off operation.
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The invention will be more closely described below
in connection with an exemplary embodiment with reference to
the accompanying drawings, wherein
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Fig. 1 shows a side view of a schematically shown
skin pulling-off apparatus according -to the invention,
Fig. 2 shows a front view along the line II - II in
Fig. 1i
Fig. 3 shows a top view of the appara-tus in Fig. 1;
and
Figs. 4 and 5 schematically illustrate two different
operationalphasesduring a skin pulling-off operation.
As shown in Figs. 1 - 3, the skin pulling-off apparatus
in the illustrated embodiment comprises a vertically disposed,
rectangular steel frame 1 having vertical side members
carrying suitable bearing means 2 for pivotal mounting of
one end of a lifting beam means 3. The bearing means 2 may
be displaceably mounted on the side members of the frame.
The lifting beam means 3 comprises apair of e.g. telescopically
extendable tube and rod members 4 and 5 and a pair of
bracing members 6 extending therebetween. On the free ends
of the rod members 5 there are mounted bearings 7 for the
support of an essentially horizontal drum 8 which is to be
20 described below. The lifting beam means with the drum is ;
pivotable upwards and downwards by means of an operating
; means which in the illustrated embodiment comprises a
- hydraulic cylinder and piston unit 9 (cylinder I). At its
upper end the hydraulic cylinder 9 is pivotally connected
to an upper cross member of the frame 1, whereas the lower
free end of the piston rod 10 is pivotally mounted between
a pair of holding pla-tes 11 attached on the bracing members
6 and provided with a plurality of apertures 12 or the like
for adjustable mounting of the piston rod end.
On the subgrade, at a suitable distance in frontof the
lifting beam means 3, there is provided a clamping means
with a combined holding and stretching function which is to
be described more closely below in connection wi-th the use
of the apparatus. In the illustrated embodiment the clamping
means comprises a supporting frame 13 for the support of a
hydraulic cylinder/piston unit 14 (cylinder II). At its
lower end the hydraulic cylinder is pivotally connected to
the supporting frame 13, and by means of a supporting means
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15 the cylinder is supported in an oblique position as shown
in Fig. 1. On the upper end of the piston rod 16 of the
cylinder/piston unit 14 there is moun-ted a gripping head
means 17 with gripping jaws 18 which are operable by means
- 5 of a hydraulic cylinder/piston unit 19 (cylinder III).
Instead of the shown clamping means with gripping head
means and hydraulically operated gripping jaws, the clamping
means may simply consis-t of a suitable hook means onto which
the forlegs of the sheep carcas may be hooked. A number of
such hook means may be provided a-t different heights along
a rod which is pivotally mounted and fixable in a desired
position on a suppor-ting frame, so that one achieves
adaptation for clamping ofcarcasses of different sizes, and
simultaneously, by pivoting of the rod, may pull the carcass
outwards from the drum to the most suitable position for
pulling-off of the skin.
In the shown embodiment the drum 8 comprises a central
cylindrical portion 20 which at each end merges into a portion
21 having a gradually increasing diameter in the direction
~ towards the ends of the drum, and e.g. having a conical shape.
On each drum end there is provided an essentially circular
end plate 22 having a larger diameter than that of the outer
ends of the drum 8 and being provided with a hook portion 23
which in the illustrated example is formed by an essentially
tangentially extending notch in the end plate in question.
The importance of this concave or saddle-like drum shape
is to be described more closely below in connection with the
operation of the apparatus.
For rotation of the drum 8 a motor 24, which e.g. may
be of hydraulic type' is provided at the free end of one of
the lifting beam rod members 5. The motor is supported by
a bracket means 25 attached to the rod member 5, and is
connected to the shaft of the drum 8 through a suitable clu-tch
26.
For the operation of the described operating and driving
means which are included in the shown embodiment of the
apparatus according to the invention, there is provided a
hydraulic unit 27 which, at the base of the vertical steel
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frame 1, is supported by a base plate 28 which is in turn
supported on a frame 29 through buffers 30.
The various hydraulic and/or electric supply conduits,
and the various connections and control means, such as control
valves and the like, which are necessary for operation and
control of the apparatus, are not illus-tra-ted in -the
schematic drawing figures. The arrangement of these means
is of technical kind and -therefore is not more closely shown
and described, as a person skilled in the ar-t will realize
the necessary arrangement in view of the following description
of the operation of the apparatus. Similarly, it will be
seen that the apparatus may possibly be adapted for pneumatic
instead of hydraulic operation.
In the following a-skin pulling-off operation will be
described with reference to Figs. 4 and 5.
When a sheepcarcass arrives at the skin pulling-off
apparatus, it has been flayed from -the breast and just beyond
the navel. The skin is cut from knee joint to knee joint
at the front edge of the breast. The forelegshave been cut
-20 off at theknee joint, but the metatarsal bones stick to
the skin.
The initial or zero position of the apparatus is shown
in Fig. g. The sheep or lamb c~arcas~s 31 is suspended from the
hind legs in connection with a suggested overhead conveyor
32. Further, the sheep carcass is clamped in -that the ends
of the "antibrachial bones" (i.e. the forelegsabove the
knee joint) are introduced into and clamped between the
gripping jaws 18 of the clamping means, the cylinder III
being activated for this purpose. As mentioned, the meta-
tarsal bones stick to the skin and are introduced in thenotches in the drum end plates 22 and thus secured by means
OI the hooks 23 at each end of the drum.
The drum and the lifting beam now start automatically
and synchronously~ and -the drive motor 24 rotates the drum 8
in the direction of the arrow A in Fig. 4 at the same time as
the cylinder I is instructed for upwards directed stroke
movement with a set, reduced speed, so that one achieves the
correct angle for the pulling-off of the skin across the
shoulder portion of the carcass, the skin now being wound onto
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the drum (in Figs. 4 and 5 the inner side of the skin is
marked as an hatched area). As shown in Fig. 4, the
movement of the lifting beam 3 is s-tar-ted from a somewha-t
lowered position in relation to the horizontal, and the
synchronized movement of the l:ifting beam and the drum is
adjusted so that one achieves the particular and intended
pulling angle resulting in optimum pulling-off of the skin.
When the drum has been raised a suitable distance
(normally about 20 cm), cylinder I gets instruction or order
to continue its stroke, but now with full speed, at the same
time as cylinder II gets order for stroke, i.e. downward
movement of the pis-ton rod 16 with the clamping means. The
antibrachial bones and therewith the sheep caracass are thereby
stretched obliquely downwards and outwards from the lifting
beam and the drum, such as it appears from Fig. 5 (the
carcass is normally pulled somewhat more ou-twards from the
drum than shown in the Figure). Thus, the skin is pulled
off from the back a-t an angle of ca. 25 - 30.
The special configuration of the drum results in that
the pressure on the skin and the sides and back of the carcass
is equalized and distributed around the carcass itself, so
that it does not crack. The flank and the rearward part of
the back (marked with x in Fig. 4) are critical points in the
use of a skin pulling-off apparatus, and without the
special shape of the drum, the flank would crack and the
membrane on the leg would be pulled off together with the
skin.
By use of e.g. a straight drum it would be necessary
with substantially more preparatory work during the slaughtering
as the flank and the sides would then have to be flayed
manually. With the present skin pulling-off apparatus,
however, the sheep carcass is flayed approximately 10 cm
on each side from the breast and just beyond the navel, so
that the preparatory work may be made much simpler. The-re
will be less flaying, so that the second-class percentage
of the skins becomes smaller. Less flaying further involves
that the slaughtering may be carried out more hygienically
and less laboriously.
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When the lifting beam is at the top and the skin has been
pulled off the carcass, the metatarsal bones are cut off
from the skin by means of a pair of knives (no-t shown)
arranged in connection with the overhead conveyor. There-
after the lifting beam returns to i-ts initial position at
the same time as the drum is rotated in -the direct.ion
opposite to the winding direction, so tha-t the skin falls
down from the drum and the apparatus thus is ready for
another working cycle.
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