pallet lifter case study
TRANSCRIPT
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EGM 2169 F1
Design of a Pallet Lifter
Prepared by,
Lim Kim Lean
(J07003341)
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Pallet Standardization
Recommended Pallet Size
4-way entry, 1000mm x 1200mm pallet is the recommended standard for the grocery and
fast-moving consumer goods industry. The standard pallet shall have a safe working load of
minimum one tonne.
RECOMMENDED PALLET
1200mm x 1000mm 4-way entry pallet is in accordance with the ISO6780 specification.
Nominal Dimension of pallet (L or W) Entries and openings
L1 and W1 max. L2 and W2 min.
1000 150 720
1200 150 770
Dimensions in millimeters
Why 1000mm x 1200mm pallet?
Compatible with standard ocean going containers and the majority of trucks
Dominant size used in Asia (China, Hong Kong, Thailand, Malaysia, Indonesia, Philippines andSingapore)
Endorsed by ECR Asia Conform to International Standard - ISO 6780 'General-purpose flat pallets for through transit
of goods - Principal dimensions and tolerances'
Conform to Singapore Standard - SS 334 'Specification for Timber Pallets'
Major retailers in Singapore have already adopted this standard
Sufficiently wide for drive in racking.
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Benefits of Pallet Standardization
Standardization of pallets provides the platform for pallet exchange. In the ideal scenario, goodscan be transported from the manufacturer, through the distributor, to the retail store on the samepallet. By eliminating the need for manual transfer of goods to another pallet, productivity and workefficiency are improved. The reduction in both labour and handling of goods will reduce delivery and
transfer costs. Standardization of pallet sizes will in turn allow standardization of palletisers, rackingand warehouse design. This will result in economy of space and facilitate automation. Other benefitsinclude the following:
Reduction in multiple handling
Reduction of damaged goods losses through minimal manual handling
Reduction in number of transportation trips
Minimization of the wastage of pallets
Elimination of the need for sorting of pallets
Reduction of unloading time for suppliers
Reduction in warehouse storage cost Facilitates the concept of shared assets
Facilitates regional trade and pallet pooling activities
ISO Standard Pallets (ISO 6780: Flat pallets for intercontinental materials handling)
* ISO 48" x 40" - Primarily used in North America
* ISO 1200mm x 1000mm - Primarily used in Europe and Asia
* ISO 1140mm x 1140mm - Primarily used in Australia
* ISO 42" x 42" - Worldwide use
* ISO 1100mm x 1100mm - Primarily used in central Asia
* ISO 1200mm x 800mm - A pallet specifically designed for European use to fit through standard
doorways.
North American Pallets
* Grocery Manufacturers' Association (GMA) 48"x40"
* 42"x42" - Primarily used for communications equipment and paint.
* 48"x48" - Primarily used for drums
* 40"x48" - Primarily used for military and cement shipments
* 44"x44" - Primarily used to handle chemical drums
* 36"x36" - Primarily used in the beverage industry
* 48"x36" - Primarily used for Shingle Manufacturers
Australian Standard Pallet1165mm x 1165mm - The Australian Standard Pallet is a pallet size commonly found in Australia but
found rarely elsewhere. It is a square hardwood pallet which fits perfectly in the RACE container of the
Australian Railway, but is ill suited to fitting in the standard ISO containers used around the globe.
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Examples of various types of wooden Pallets (UK sizes)
In many situations, recycled or reconditioned pallets are the natural choice. Some of the benefits of usingrecycled pallets are:
y New pallets attract packaging waste and have cost implications to customer. Reconditioned palletsdon't.
y Used pallets are exempt from the packaging waste regulations - so there is less administration andpaperwork for you
y Recycled pallets are a cheaper, often more readily available optiony Reconditioned pallets may often be stronger than new ones (providing they are repaired to their
original specification). Recent USA research showed that the average used pallet is 13% strongerthan new, because air drying (seasoning) during usage increases the wood strength.
Pallet Ref Size, mm Weight,kg
LoadingCapacity,Kg
Comments
UK1:
4 way Grade 1
pallet
Short board pallet
1000x1200 15 - 251000 -
1500
Top gradestandard pallet.
Heavy duty.Often used infood industry
(customers canspecify a "noglass" pallet)& packagingindustry.
UK2:
4 way grade 2
pallet
Long board pallet
1000x1200 15 - 25750 -
1250
Grade 2 pallet.Heavy duty.Often used in
manufacturing
industry& packagingindustry.
UK3:
4 way legger pallet
1000x1200 15 - 25750 -1000
Heavy dutypallet mainlyused in theplastics industry.
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UK3:
Winged Convert 1000x1200
Heavy dutypallet, the wingsfacilitate the useof shrink-
wrap. Alsoavailable as aflush sidedconvert.
UK3:
4-way PB Pallet
(fruit pallet)
1000x1200
This mid weightpallet originatesfrom the fruitindustry, and anumber of otherapplications.
UK3:
Flush sided
Convert pallet
also known as astrapper pallet
1000x1200
Mid weightpallet. Used inpackaging &distribution, &retail industry.
UK3 VMF: 1000x1200
Perimeter based
pallet (Heavyduty) originatingfromFrance. Oftenused in the glassindustry.
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UK4:
Light Weight pallet,also available as a
3-legger pallet
1000x1200 10 - 18 500 - 750
Mainly used in
the packagingindustry, oftensupplied to
retail.
UK5:
Fully reversible
2 way pallet
1000x1200 15 - 25750 -1500
A heavy dutypallet that ismainly used inthe building
industry.
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Pallet Lifter
Before designing the pallet lifter, there are few considerations that must be made. These
considerations are the strength of the material, the factor of safety, the allowable tensile and shear
stresses, dimensions of the bars and the availability of the bars in the market, modes of failures and
lastly the cost effectiveness.
Strength of material
The strength of a material is its ability to withstand an applied stress without failure. Yield
strength refers to the point on the engineering stress-strain curve beyond which the material begins
deformation that cannot be reversed upon removal of the loading. The applied stress may be tensile,
compressive, or shear. Strength is considered in terms of compressive strength, tensile strength, and
shear strength, namely the limit states of compressive stress, tensile stress and shear stress,
respectively. The effect of dynamic loading is probably the most important practical part of the strength
of materials, especially the problem of fatigue. Repeated loading often initiates brittle cracks, which
grow slowly until failure occurs. However, the term strength of materials most often refers to various
methods of calculating stresses in structural members, such as beams, columns and shafts. The methodsthat can be employed to predict the response of a structure under loading and its susceptibility to
various failure modes may take into account various properties of the materials other than material
(yield or ultimate) strength. For example failure in buckling is dependent on material stiffness.
Uniaxial stress is expressed by:
where Fis the force [N] acting on an areaA [m2]. The area can be the undeformed area or the deformed
area, depending on whether engineering stress or true stress is used. Yield stress is the lowest stress
that gives permanent deformation in a material. Tensile stress is the stress state caused by an applied
load that tends to elongate the material in the axis of the applied load. The strength of structures ofequal cross sectional area loaded in tension is independent of cross section geometry. Materials loaded
in tension are susceptible to stress concentrations such as material defects or abrupt changes in
geometry. Shear stress is the stress state caused by a pair of opposing forces acting along parallel lines
of action through the material.
Factor of safety is a design constraint that an engineered component or structure must achieve.
The actor of safety is determined by the designer to obtain the allowable stresses of the component.
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Pallet Lifter Design
Factor of safety: 4
Beam dimensions: (1&2)=75x100x640mm, (3)=65x65x1500mm
Beam thickness: 10mm
B
eam weight: (1&2)=15.331kg, (3)=25.905kgShackle mounts dimensions: 60x60x40mm, outside 60mm, inside 36mm
Locking pin dimensions: 19mmX100mm
Total weight: 1910.74kg = 18744.3N
Pallet weight: approx. 25kg
Maximum loading capacity: 1800kg (based on calculation)
Yield strength for: ASTM A500 = 315MPa, ASTM A36 = 250MPa
Allowable tensile stress, allow:
ASTM A500:- 315M/4 = 78.75MPa
ASTM A36 :- 250M/4 = 62.50MPa
Allowable shear stress, allow:
ASTM A500:- 315M/8 = 39.375MPa
ASTM A36 :- 250M/8 = 31.250MPa
No. Parts Material Quantity
1 Main Support Beam ASTM A500 (Mild Carbon Steel) 1
2 Adjustable Support Beam ASTM A500 (Mild Carbon Steel) 1
3 Pallet Support Beam ASTM A500 (Mild Carbon Steel) 2
4 Shackle Mount ASTM A36 (Steel Alloy) 4
5 Locking Pin ASTM A36 (Steel Alloy) 2
*Locking pin is connected to the adjustable support beam by a chain.
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Component:-
1. Main Support BeamFailure mode:-
- Shearing failure of the bar at contact point- Tensile failure of the welded joints- Shearing failure of the welded jointsArea = 0.013m x 0.02m + 0.055m x 0.01m
= 8.1 x 10-4
m2
Allowable force, Fallow = 78.75M x 8.1x10-4
= 63787.5N
Welded joints
- Butt jointF = tx l x
Fallow = 0.005 x 0.065 x 39.375M
= 12796.875N x 4 (for single bar)
- Transverse fillet jointF = A x = 0.707slx
Fallow = 0.707(0.01)(0.065)(78.75M)
= 36189.56N x 4 (for single bar)
3. Pallet SupportBeam
Failure mode:-
- Tensile failure of the beam at pin insertsArea = 0.045m x 0.02m + 0.045m x 0.02m
= 1.8 x 10-3m2Allowable force, Fallow = 78.75M x 1.8x10
-3
= 141750N
- Deflection of beamIx =
(0.065)
4
(0.045)
4
= 1.146x10-6
m4
=
, M =
, =
78.75M =
W = 9256.15N (for single bar)
Maximum loading 1800kg
max =
= 2.81x10-3
m
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4. Shackle mount
Failure modes:-
- Tensile failure of the part- Shearing failure of the part- Tensile failure of the welded jointArea = 0.024 x 0.04
= 9.6x10-4
m2
For tensile stress,
Fallow = 9.6x10-4
x 62.5Mpa
= 60000N
For shear stress,
Fallow = 9.6x10-4
x 31.25Mpa
= 30000N
Welded joints
For vertical weld (L=0.06)
Fallow = 0.707(0.005)(0.06)(78.75M)
= 16702.875N (tensile)
Fallow = 0.707(0.005)(0.06)(39.375M)
= 8351.44N (shear)
For horizontal weld (L=0.04)
Fallow = 0.707(0.005)(0.04)(78.75M)
= 11135.25N (tensile)
Fallow = 0.707(0.005)(0.04)(39.375)
= 5567.625N (shear)
Total allowable tensile force = 55676.25N (on single mount)
Total allowable shear force = 27838.13N (on single mount)
5. Locking pin
Failure mode:-
- Shearing of the pin at contact pointArea = (0.009)
2
= 2.54x10-4
m2
Fallow = (31.25M)(2.54x10-4
)
= 7952.16N (on one side)
Total allowable force on one pin = 15904.32N
Two pins can support 31808.64N
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Attachments
JawInsideWidth
W
InsideLengthS=2.2
W
BDYMaterialDiameter
d
Pin
DiameterD
EYE
OutsideDiameter
Safe Working Load(Tonnes)
Grade30
Grade40
Grade63
Grade80
18 40 10 12 24 - - 1.0 -20 44 12 14 28 - 1.0 1.25 2.022 49 14 16 32 1.0 1.25 1.6 -25 55 16 19 38 1.25 1.6 2.0 3.2528 62 17 20 40 1.6 2.0 2.5 -32 70 19 22 44 2.0 2.5 3.2 4.7534 79 22 26 52 2.5 3.2 4.0 6.540 88 24 28 56 3.2 4.0 5.0 8.545 99 27 31 62 4.0 5.0 6.3 9.550 110 30 35 70 5.0 6.3 8.0 12.056 124 34 39 78 6.3 8.0 10.0 13.563 139 38 44 88 8.0 10.0 12.5 17.070 154 43 50 100 10.0 12.5 16.0 25.080 176 48 55 110 12.5 16.0 20.0 35.090 198 54 62 124 16.0 20.0 25.0 -100 220 60 69 138 20.0 25.0 32.0 42.0107 236 66 76 152 25.0 32.0 40.0 50.0117 258 71 82 164 32.0 40.0 50.0 65.0130 286 79 91 182 40.0 50.0 63.0 -140 308 84 97 184 50.0 63.0 80.0 83.0153 337 93 110 220 63.0 80.0 - 100.0
The highlighted region is the dimensions for the D-shackle that will be used together with the pallet
lifter as shown in the picture. The grade C D-shackle is chosen to be used with the pallet lifter.
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Malaysian Market
Product Description
FOR SALE WITHIN MALAYSIA ONLY.
ASTM A-500 MILD STEEL SQUARE HOLLOW SECTIONS (SHS)
20MMX20MM..30X30..32X32..35X35..38X38..40X40..50X50..60X60..
65X65..75X75..80X80..90X90..100X100..120X120..125X125..150X150.
.180X180..200X200..250X250..300X300..350MM X 350MM.
ASTM A-500 MILD STEEL RECTANGULAR HOLLOW SECTIONS (RHS)
38MMX19MM..38X25..50X25..65X35..65X38..75X25..75X38..75X50..
100X50..100X75..120X60..120X80..125X50..125X75..150X50..150X75..
150X100..160X80..200X100..200X150..250X150..300X200..400X200..
400mm X 300mm..
References:
- http://www.cwhsb10.com/sdp/900713/4/pd-4573542/5345245-1868747/SQUARE_AND_RECTANGULAR_HOLLOW_SECTIONS.html
- http://www.liftarts.com/DShackles.html- http://www.whirlowdale.com/UK-reconditioned-pallets.aspx- http://en.wikipedia.org/wiki/ASTM_A500- http://en.wikipedia.org/wiki/ASTM_A36- http://en.wikipedia.org/wiki/Strength_of_materials- www.gs1hk.org/files/gs1/document/Pallet%20Standardisation.pdf