EP0281287A1 - A lifting sling and a method for manufacturing it - Google Patents

A lifting sling and a method for manufacturing it Download PDF

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Publication number
EP0281287A1
EP0281287A1 EP88301423A EP88301423A EP0281287A1 EP 0281287 A1 EP0281287 A1 EP 0281287A1 EP 88301423 A EP88301423 A EP 88301423A EP 88301423 A EP88301423 A EP 88301423A EP 0281287 A1 EP0281287 A1 EP 0281287A1
Authority
EP
European Patent Office
Prior art keywords
core
mantle
sling
shorter
lifting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP88301423A
Other languages
German (de)
English (en)
French (fr)
Inventor
Pekka Servanto
Esa Kiili
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LASSILA AND TIKANOJA Oy
Original Assignee
LASSILA AND TIKANOJA Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from FI870757A external-priority patent/FI78440C/fi
Application filed by LASSILA AND TIKANOJA Oy filed Critical LASSILA AND TIKANOJA Oy
Publication of EP0281287A1 publication Critical patent/EP0281287A1/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C1/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles
    • B66C1/10—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means
    • B66C1/12—Slings comprising chains, wires, ropes, or bands; Nets
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B7/00—Details of, or auxiliary devices incorporated in, rope- or cable-making machines; Auxiliary apparatus associated with such machines
    • D07B7/16—Auxiliary apparatus
    • D07B7/165—Auxiliary apparatus for making slings

Definitions

  • the present invention relates to the lifting sling defined in the preamble of the principal claim and to the methods for its manufacture, defined in the preamble of a claim.
  • a lifting sling such as this is endless and made from textile material, and it is intended on the one hand for being fitted around the article to be lifted and on the other hand for being fitted to the hoist.
  • the lifting sling is made up of a loadbearing core which is made up of one or more coils of synthetic thread, film or synthetic split thread, and of a tubular coating loosely surrounding the core. The ends of the tubular coating are connected to one another.
  • the coil of thread is made up of thread wound in several layers inside the coating.
  • Slings of this type are previously known.
  • a lifting sling of this type the coating of which is a seamless tube. Owing to the method of manufacture, the coating of such a sling is longer than its core and forms transverse folds over the entire length.
  • the object of the present invention is to provide a seamed or seamless lifting sling the coating of which is primarily smooth and does not form transverse folds along its length.
  • the lifting sling according to the invention having a coating or mantle shorter than the length of the core made up of the loadbearing coil of thread, provides the follow­ing advantages:
  • the mantle During lifting, the mantle does not form folds or wrinkles which are easily worn out. Thus a longer useful life of the sling is achieved.
  • no fold is formed at the lifting arm and the loop part of the sling; such a fold may prevent smooth sliding of the sling in the hoisting loop, in which case the lifting arm moves in the loop in jerks, and as a result there may be melting damage caused to the loadbearing coil of thread by friction.
  • a smooth lifting sling i.e. one without wrinkles in the coating, is easier to fit in a hook and also around the load to be lifted.
  • the slipperiness of the coating can be regulated by the manufacturing technique, and thus the optimum form in terms of the behavior of the lifting sling can be sought.
  • the sling according to the invention is formed most preferivelyably by first making the core by winding one or more threads into a coil, the diameter of the coil being slight­ly greater than the diameter of the completed sling.
  • the coating is fitted around this coil by bending an open coat­ing band over the coil and by seaming the edges of the band to one another. Thereafter the ends of the band are passed one inside the other and secured together by, for example, longitudinal seams at both edges of the joint or in the middle of the joint. For unhampered joining of the ends of the coating, the coating must be slightly longer than the core.
  • a tubular coating is fitted over the coil; this is done by gathering a tube of suitable length on a bar, whereafter the neces­sary number of rounds of the thread or threads of the coil are passed through the gathered tube, whereafter the bar is removed and the ends of the tube are connected to each other.
  • the produced sling corresponds to the state of the art of Finnish Patent 48570, and it has a core slightly longer than the coating or mantle, and it has transverse folds.
  • the stitched sling may thereafter be subjected to heat treatment for a few minutes, whereupon the mantle shrinks in length and width while the core does not shrink at all or shrinks considerably less, so that the length of the heat-treated mantle is at least 2 % shorter than the core.
  • the shrinkage may be up to 10 %, but with this great a difference between the core and the mantle there easily arise problems with the ultimate strength on elongation.
  • Such a shrinkage ratio is achieved only through a suitable selection of the raw materials for the mantle and the core and by continuing the heat treatment for a precisely cal­ culated period.
  • the length of the coil is at least 2 % more than the completed sling and, furthermore, it is necessary to take into account the overlapping band parts in the area of the joint.
  • the coil of thread must be gathered by means of a machine over the entire length of the longitudinal seam.
  • a mantle or tube of a certain length is gathered on a bar, whereafter the thread or threads of the coil are passed through the tube in the suitable number of rounds of suitable length, in accordance with the technique of the said Patent 48570.
  • a length at least 2 % greater is selected as the length of the coil, taking into account also the overlap in the area of the joint, whereby the desired difference in length is obtained between the mantle and the core.
  • the core When joining the ends of the mantle, the core must be gathered inside the mantle by means of a special tool so as to make the area of the joint smooth for the stitching stage.
  • the break elongation values and elastic properties of the mantle and the core must be such that in a loading situa­tion the mantle is first capable of stretching to the straightened length of the core and additionally to the elongated length of the core, caused by the load, without the mantle being broken by this elongation.
  • the mantle material must therefore be capable of stretching more than the core stretches.
  • Sufficient elastic properties are in­deed obtained for the mantle material in heat treatment, i.e. in general in the dyeing treatment, since after the dyeing the break elongation value of the core material will be approximately its break elongation plus the irreversible shrinkage caused by the dyeing.
  • the degree of shrinkage In calculating the degree of shrinkage, it must be taken into account that the shrinkage measured after loading is something else than the shrinkage measured before the load­ing, because part of the shrinkage is irreversible. What is meant in speaking of shrinkage, and respectively the length difference between the mantle and the core, is the irreversible shrinkage, i.e. the shrinkage of the sling in the resting position, after loading.
  • the degree of shrink­age is also affected by the structure of the mantle.
  • the raw materials of the core and the mantle may be of different materials or of the same material.
  • the material used for the core is, of course, treated so that it will not shrink at all or shrinks considerably less than the material used for the mantle.
  • mantle and/or core materials of lifting slings include various polyesters, polyamides and polypropylenes and polyethylenes. According to one inter­national standard, the mantle material and the core mate­rial must be of the same raw material. For example, the compatible types listed below can be found among polyesters and polyamides. Their break elongation, shrinkage and strength values are as follows:
  • HD polyester can also be used as mantle material, in which case polyester, polyamide or polyprolylene can be used as core material.
  • Example 1 the mantle material is polypropylene and the core material polyester (i.e. a combination not in compliance with the standard), and in Example 2 the mantle material and the core material are both polyester, combination 1 in the Table.
  • the treatment temperature was raised to 120 °C, the duration of the treatment being the same, the poly­propylene shrank 8 %.
  • the break elongation value of Polyester 785 Celanese after heat treatment (dyeing) was approximately 32 % (12.5 + 21 %).
  • the break elongation value of the core thread was 13.5 %. If the core thread stretched all the way to the breaking limit in a loading situation, the mantle would still have a stretching allowance of 20 % left.
  • numeral 1 indicates the coating or mantle of the sling
  • 2 the individual threads constituting the coil
  • 3a indicates the outer end of the mantle and 3b its inner end
  • 4 the longitudinal seams connecting the ends 3a and 3b.
  • the figure according to Figure 2 shows a greater number of rounds of the coil, although not the real number. The number of the rounds, of course, depends on the strength required.
  • the lifting sling according to the invention can also be produced mechanical strictlyly, i.e. by making, for example, the area of the joint of the tube elastic by producing the joining with the aid of resilient rubber means or the like, in which case the mantle and the core will stretch an equal degree in a load­ing situation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials For Medical Uses (AREA)
  • Load-Engaging Elements For Cranes (AREA)
EP88301423A 1987-02-23 1988-02-19 A lifting sling and a method for manufacturing it Withdrawn EP0281287A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FI870757A FI78440C (fi) 1987-02-23 1987-02-23 Lyftstropp och foerfarande foer dess tillverkning.
FI870757 1987-02-23
FI880543A FI880543A (fi) 1987-02-23 1988-02-05 Lyftstropp och foerfarande foer dess framstaellning.
FI880543 1988-02-05

Publications (1)

Publication Number Publication Date
EP0281287A1 true EP0281287A1 (en) 1988-09-07

Family

ID=26158093

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88301423A Withdrawn EP0281287A1 (en) 1987-02-23 1988-02-19 A lifting sling and a method for manufacturing it

Country Status (3)

Country Link
EP (1) EP0281287A1 (no)
FI (1) FI880543A (no)
NO (1) NO880751L (no)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2760734A1 (fr) * 1997-03-17 1998-09-18 Dakomex Comp Franc Des Ets Procede de fabrication d'une elingue ou d'une sangle et elingue ou sangle ainsi obtenue
US6422624B1 (en) * 2001-03-20 2002-07-23 Lift-All Company, Inc. Wire rope roundsling with inspection window
WO2003059462A1 (de) * 2002-01-18 2003-07-24 Mammut Tec Ag Schlinge
WO2009058301A1 (en) * 2007-10-31 2009-05-07 Slingmax, Inc. Synthetic sling whose component parts have opposing lays
WO2010097328A1 (de) 2009-02-27 2010-09-02 Spanset Inter Ag Rundschlinge zum heben von lasten
FR2959223A1 (fr) * 2010-04-26 2011-10-28 Pms Internat Elingue de levage
CN106051048A (zh) * 2016-06-29 2016-10-26 江阴泰阳成索业有限公司 纤维带索具及其生产方法
CN107416672A (zh) * 2017-08-28 2017-12-01 巨力索具股份有限公司 一种吊装带及其长度精度控制方法
US12012693B2 (en) 2019-07-11 2024-06-18 Cortland Industrial LLC Method of manufacturing an endless loop

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1325207A (en) * 1970-06-17 1973-08-01 Spanset Inter Ag Straps
GB1446935A (en) * 1972-11-08 1976-08-18 Skepps & Fiskeritillbehoer Endless lifting loop
EP0116916A2 (de) * 1983-02-22 1984-08-29 Spanset Inter Ag Rundschlinge, daraus gebildete Stroppe oder daraus gebildete Rundschlingenmatte

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1325207A (en) * 1970-06-17 1973-08-01 Spanset Inter Ag Straps
GB1446935A (en) * 1972-11-08 1976-08-18 Skepps & Fiskeritillbehoer Endless lifting loop
EP0116916A2 (de) * 1983-02-22 1984-08-29 Spanset Inter Ag Rundschlinge, daraus gebildete Stroppe oder daraus gebildete Rundschlingenmatte

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2760734A1 (fr) * 1997-03-17 1998-09-18 Dakomex Comp Franc Des Ets Procede de fabrication d'une elingue ou d'une sangle et elingue ou sangle ainsi obtenue
US6422624B1 (en) * 2001-03-20 2002-07-23 Lift-All Company, Inc. Wire rope roundsling with inspection window
WO2003059462A1 (de) * 2002-01-18 2003-07-24 Mammut Tec Ag Schlinge
US7422255B2 (en) 2002-01-18 2008-09-09 Suxhess, Hess Board & Process Consulting Sling
US7926859B2 (en) 2007-10-31 2011-04-19 Slingmax, Inc. Synthetic sling whose component parts have opposing lays
WO2009058301A1 (en) * 2007-10-31 2009-05-07 Slingmax, Inc. Synthetic sling whose component parts have opposing lays
US8322765B2 (en) * 2007-10-31 2012-12-04 Slingmax, Inc. Synthetic sling with component parts having opposing lays
WO2010097328A1 (de) 2009-02-27 2010-09-02 Spanset Inter Ag Rundschlinge zum heben von lasten
CN102333718A (zh) * 2009-02-27 2012-01-25 斯邦赛特英特股份公司 用于吊起重物的圆形吊装带
US8727406B2 (en) 2009-02-27 2014-05-20 Spanset Inter Ag Round sling for lifting loads
FR2959223A1 (fr) * 2010-04-26 2011-10-28 Pms Internat Elingue de levage
CN106051048A (zh) * 2016-06-29 2016-10-26 江阴泰阳成索业有限公司 纤维带索具及其生产方法
CN107416672A (zh) * 2017-08-28 2017-12-01 巨力索具股份有限公司 一种吊装带及其长度精度控制方法
US12012693B2 (en) 2019-07-11 2024-06-18 Cortland Industrial LLC Method of manufacturing an endless loop

Also Published As

Publication number Publication date
NO880751L (no) 1988-08-24
FI880543A0 (fi) 1988-02-05
NO880751D0 (no) 1988-02-22
FI880543A (fi) 1988-08-24

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