Meat i ng change -
Processing
Rotating Drum Downward Hide Puller
The puller can apply a force of two tonnes when pulling the hide
from a body allowing it to handle all sizes of cattle, within reason, that will be processed. This force can be altered to suit the
individual needs of plants by changing the specifications of the
hydraulic power pack.
Meat & Livestock Australia
Technology Transfer Kits
This Technology Transfer Kit is one in a series of Do-It-Yourself
(DIY) resources prepared for the Australian meat industry to
encourage the development of project engineering skills at meat
processing sites while implementing simple but useful items of
technology. This kit is designed to provide the essential information to allow processors to carry out suitable modifications
and installations at their own sites to improve some aspects of
their processing performance. As each processing site has
unique design and construction features the information in this
kit should be used as a guide only. Some modifications from this
kit, to ensure the successful application at individual sites, are
likely. No warranty is given on the outcome of the use of this kit
or the information it contains.
The prototype unit was constructed and installed at a
Queensland domestic abattoir that had previously not used a
downward hide puller. The unit has successfully operated for
some 2 years without problem, at a rate of up to approximately
60 bodies per hour.
Abattoirs will require, or should have access to, reasonable engineering skills and facilities to be capable of constructing and
commissioning the Rotating Drum Downward Hide Puller.
Description
The Rotating Drum Downward Hide Puller consists of a
hydraulically powered unit that rotates a drum that is attached to
a carriage that can travel vertically. Operators stand on enclosed
platforms mounted to either side of the drum carriage and travel
vertically with the drum. This allows the operators to apply any
necessary manual intervention, using conventional knives or air
knives, as the hide is released from the carcase surface.
DIY Kit # 4 – Rotating Drum
Downward Hide Puller
The Rotating Drum Downward Hide Puller is used with on-rail
beef dressing for an hourly capacity of up to 80 head of cattle.
Maximum capacity is dependent on the slaughterfloor layout
and possible labour utilisation. The equipment is designed for
retrofitting to on-rail dressing systems and for installation in new
slaughter lines.
The height of the operators’ stands, in relation to the carriage can
be manually varied to the desired position for each operator.
The stands, in the prototype design, are fixed horizontally but
can be modified, if required, with the fitting of air rams to the
underside of the platforms. This will give horizontal movement
in relation to the drum carriage. Towards the bottom of the vertical movement the operators’ platforms move on slides so that
the drum can be lowered as close to the floor as possible, without the platforms touching the floor.
Downward hide pulling has been proven to be a more hygienic
technique than manual flaying of the hide or upward hide
pulling. Downward hide pulling requires less manual contact
with the hide than manual flaying. During upward hide pulling
the hide can flick contamination onto the cleared surface or in
extreme circumstances can fall back against the carcase. This is
far less likely to happen with downward hidepulling as the hide
falls away from the carcase.
The near side of the drum is located at approximately 900 mm
from the centre line of the beef rail to ensure the correct combination of vertical and horizontal pull. This ensures the most
effective hide removal. The drum is fitted with two chains with
slip links to grip the hide. The slip links are used to form a noose
in the end of each chain. The freed hide from each hind leg is
passed through the noose and trapped by the tightening chains.
Rotation of the drum is such
that the near side, that nearest
the carcase, moves downward
pulling the hide away from
the carcase as well as down.
Processors currently dressing on a rail using manual flaying or
upward hide pulling can install the Rotating
Drum Downward Hide Puller at the position
where hide pulling currently occurs. Some
modification to pre-work is necessary with an
overall reduction in the level of pre-work
required.
1
Upward hide pulling also creates a carcase hygiene issue.
When the hide is at its last point of contact, at maximum elevation, it can distribute dirt particles from the outer surface of the
hide down over a large area of the exposed carcase surface and
surrounding area.
The removal of the hide is controlled with foot controls that the
operator uses to adjust the rate of vertical movement and the rate
of drum rotation. Effective hide pulling is managed by controlling the combination of these two movements.
At the end of the hide pulling operation the hide is released automatically from the slip links by reversing the rotation of the drum.
Changing upward hide pulling to downward hide pulling results
in improvements in:
Effective Operation
• Improved carcase hygiene
Care must be taken when pulling the hide over the animal’s
head so that the puller does not apply too much force to the
body. Excessive longitudinal pull can cause separation of the
vertebrae in the back and potential downgrading of the carcase.
The operators can achieve reduction of force by intervening
when the hide is pulled over the head or by head removal prior
to pulling on large cattle.
• Increased productivity
Materials
The prototype constructed, installed and still in operation in
Queensland used the following materials. Prices are at 1998
costs when installed.
Item
Materials
Hydraulic Unit inc; motor assembly, power
unit, cylinder & valves
Hydraulic Swivel Assembly
205 mm x 40 mm dia x 50 mm Polyethylene
UHMW 1000 grade
Stainless steel flanges
500 mm dia OD/150 mm dia ID x 12 mm
500 mm dia OD/75 mm dia ID x 12 mm
335 mm dia OD/273 mm dia ID x 12 mm
If it is necessary to maintain a high force on the hide puller to pull
the hide over the head, the number of bodies with separation of
vertebrae can be reduced with the implementation of stiffening
probes. These are probes that apply an electrical current to the
carcase in the region of the lower back. The electrical stimulation stiffens the muscles of the back supporting the vertebrae
against separation. Stimulation of this nature is particularly effective when low voltage carcase stimulation has not been applied
immediately after slaughter and prior to hide pulling.
Quantity
Cost
1
$10,000.00
1
4
$
$
1
1
2
$ 124.00
$ 124.00
$ 146.00
Item
Length (mm) Area (mm)
Stainless steel sections
75 x 10 flat bar
600
40 dia shaft
750
50 dia shaft (inside diameter of 40)
460
Perforated plats/Tread plate
1200 x 700
250 NB pipe sch 40
800
Mild steel sections
150 x 50 x 5 RHS
2,300
150 x 100 x 6 RHS
1,600
230 PFC
10,100
150 PFC
4,100
75 x 75 x 4 RHS
4,800
65 x 65 x 6 RHS
4,100
65 x 65 x 6 Angle
8,800
50 x 50 x 6 Angle
2,700
32NB pipe
4,800
25NB pipe
4,800
100 x 4 flat bar
4,000
75 x 6 flat bar
400
60 x 10 flat bar
360
50 x 10 flat bar
240
40 x 10 flat bar
720
75 x 10 flat bar
3,450
10 mm mild steel plate
1,100 x 100
12 mm mild steel plate
120 x 240
16 mm mild steel plate
1,230 x 275
20 mm mild steel plate
1,420 x 355
70 mm block
220 x 240
50 mm block
130 x 240
Item
Length (mm) Area (mm)
40 mm block
40 x 600
50 mm x 50 mm square bar
110
40 mm round bar
2900
40 mm nylon square
1200
Stainless steel shackling chains
3900
Total
Suppliers:
Applied Hydraulics & Lubrication; Brisbane (hydraulic equipment)
Steelmark – Eagle & Globe
Midway Metals
Ludowici Rubber & Plastics; Brisbane (polyethylene, nylon)
Beaver Sales; Brisbane (chain)
Suitable stiffening probes are commercially available and can be
fitted to this design.
Benefits
Several advantages have been identified from using the Rotating
Drum Downward Hide Puller when compared to both manual
flaying and upward hide pulling.
Benefits against manual flaying
Manual flaying requires a very high skill level for effective hide
removal without damaging both hide and carcase. Mechanical
hide pulling reduces the physical nature of this task and the level
of knife work required. The use of air knives further reduces the
accuracy that is required to, safely and effectively, assist the separation of the hide and the carcase. Hide to flesh contact is difficult to eliminate during manual flaying. Even when the operator’s skill level is high it is difficult not to damage the hide with
cuts or scores. Selvage is often lost from the carcase.
Altering a manual flaying system to a downward hide pulling
system results in benefits in the areas of:
350.00
620.00
Cost
$
$
$
$
21.00
45.00
15.00
430.00
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
75.00
101.00
542.00
141.00
99.00
116.00
77.00
23.00
44.00
34.00
37.00
3.00
4.00
2.00
5.00
42.00
17.00
6.00
84.00
153.00
62.00
25.00
Cost
$ 17.00
$
4.00
$ 65.00
$13,653.00
• Occupational Health and Safety.
• Increased productivity.
Drawings
• Improved carcase hygiene.
The appended engineering drawings show:
• Increased yield remaining with the carcase
S0360101
Hide puller arrangement
• Greater hide value through less damage
S0360102
Hide puller main carriage
S0360103
Hide puller carriage roller guide arm
S0360104
Hide puller drum
S0360105
Hide puller support frame
S0360106
Hide puller platforms
S0360108
Hide puller chain requirements
Benefits against upward hide pulling
Upward hide pulling requires more pre-work than downward
hide pulling. When upward hide pulling the forelegs have to be
restrained by chains and hooks that are fitted through the tendons and attached to a post. These chains and hooks must be
sterilised between carcases adding extra labour and time to the
hide pulling operation.
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3
4
5
6
7
8
9
10
11
Video presentation
Approximately 7.8 minutes of the hide puller in operation showing the important features of design, construction and operation
are provided on the Meat and Livestock Australia Technology
Transfer DIY Kits’ Support Video. Footage relevant to the
Rotating Drum Downward Hide Puller Unit DIY Kit is approximately located between VCR real time counter units 22:00 to
27:50.
Acknowledgments
Meat & Livestock Australia have prepared this kit with support
from the Australian Meat Processors Corporation.
Equipment design & project management
Australian Meat Technology Pty Ltd
Equipment construction, installation, commissioning and operation
Killarney Abattoir, Killarney, QLD
Contact
Processing and Product Innovation
Meat and Livestock Australia
Tel: (02) 9463 9166 Fax: (02) 9463 9182
165 Walker Street, North Sydney NSW 2060
Tel: (02) 9463 9333 Fax: (02) 9463 9393 www.mla.com.au
Published November 2000
ISBN: 1 74036 816 9
© Meat and Livestock Australia
MLA makes no representation as to the accuracy of any information or advice contained in this document and excludes all liability, whether in contract, tort
(including negligence or breach of statutory duty) or otherwise as a result of reliance by any person on such information or advice.