US3697118A - Automatic lifting tongs - Google Patents

Automatic lifting tongs Download PDF

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Publication number
US3697118A
US3697118A US93698A US3697118DA US3697118A US 3697118 A US3697118 A US 3697118A US 93698 A US93698 A US 93698A US 3697118D A US3697118D A US 3697118DA US 3697118 A US3697118 A US 3697118A
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US
United States
Prior art keywords
jaws
latch member
opening
projection
tongs
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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.)
Expired - Lifetime
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US93698A
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English (en)
Inventor
Crichton Lockhart Johnstone
John Woodhouse Paton
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Individual
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Individual
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Publication date
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Publication of US3697118A publication Critical patent/US3697118A/en
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    • 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
    • B66C1/42—Gripping members engaging only the external or internal surfaces of the articles
    • B66C1/422—Gripping members engaging only the external or internal surfaces of the articles actuated by lifting force

Definitions

  • ABSTRACT Lifting tongs have a pair of primary arms forming a pair of jaws for engagement with a workpiece.
  • a latch mechanism interlocks the two arms so that the tongs can be opened and closed automatically by successive movements opening the jaws. Following a first movement opening the jaws, the latch mechanism is engaged to hold the jaws open; the latch mechanism is disengaged by a subsequent movement opening the jaws whereupon it releases the arms to allow the jaws to close.
  • the latch mechanism includes a pivoted latch member mounted on one arm, which latch member is movable between two equilibrium positions to define the engaged and disengaged positions of the latch mechanism.
  • This invention relates to lifting tongs.
  • the invention is particularly applicable to lifting tongs which are intended to lift relatively heavy workpieces, for example, ingots such as are handled in Steel Works, and which must for safety reasons be remotely controlled.
  • Lifting tongs of this kind must be capable of retaining in an open position the jaws which engage with the workpiece and provide quick and easy closure of the jaws onto the workpiece after they have been placed in the correct position with respect to the workpiece.
  • the tongs must in addition provide for quick and easy opening of the jaws to release the workpiece when this has been hoisted into position and subsequently again to retain the jaws open for a further sequence of operatrons.
  • lifting tongs comprising a pair of primary arms pivotally connected to one another to form a pair of jaws for engagement with a workpiece, and a latch mechanism connected to the primary arms, the latch mechanism including a pivotally mounted latch member which adopts a first position where it prevents closure of the jaws, and a second position where it allows closure of the jaws, in response to successive opening movements of the jaws.
  • the latch member is pivotally mounted upon one arm of the tongs and is adapted to engage with a cooperating projection provided on the other arm.
  • the latch member is pivotally mounted on one arm and has an opening to receive a cooperating projection on the other arm, the opening being so shaped that the projection is moved around at least part of the periphery of the opening by the said successive opening movements.
  • the opening has a region adapted to restrain the projection against movement corresponding to closure of the jaws
  • the periphery may include a re-entrant portion for engaging the projection to restrain its movement with respect to the latch member in the direction corresponding to closure of the jaws.
  • selective restraint against movement may be provided by an auxiliary latch member which is displaced by the projection on one part of its movement corresponding to opening of the jaws and which subsequently acts to restrain the projection against movement corresponding to closure of the aws.
  • the said first and second positions of the pivoted latch member are two equilibrium positions.
  • the latch member reaches each equilibrium position during relative movement between itself and the projection on the said other arm of the tongs corresponding to closure of the jaws, and is displaceable from the equilibrium position only by relative movement corresponding to opening of the jaws.
  • the projection in one equilibrium position is urged against that region of the opening which contains the re-entrant portion or auxiliary latch, to permit engagement to occur.
  • the latch member subsequently is moved into the second equilibrium position in which the projection is urged against the opposed region of the opening preventing re-engagement with the re-entrant portion as the cycle is continued.
  • the latch member is moved between the equilibrium positions by cam reactions between the projection and the profile of the opening.
  • the equilibrium positions may be maintained solely by gravity or may be assisted by an over-center spring arrangement suitably incorporated into the latch mechanism.
  • the projection may incorporate a roller effective to reduce the frictional drag produced by movement relative to the periphery.
  • the arms of the tongs are in the form of spaced plates secured together by bridges; in this case the latch mechanism is disposed between the plates to provide protection particularly against mechanical impact.
  • the latch mechanism may be secured between any region of any pair of arms of the tongs which cooperate to produce opening and closure of the jaws.
  • FIG. 1 is a perspective side view of the tongs according to the invention
  • FIG. 2 is a sectional side view which shows the tongs fully extended with the jaws closed in engagement with a workpiece
  • FIG. 3 is a sectional side view of the tongs shown in FIG. 1 and in one operational position
  • FIG. 4 is a fragmentary view of the latch mechanism shown in FIG. 2 but in a second operational position.
  • FIG. 5 is a view of an alternative latch mechanism shown in the same position as the latch mechanism of FIG. 4.
  • the lifting tongs comprise two primary arms 2 and 4 each in the form of two identical spaced plates secured together by bridges S in a manner well known in the art.
  • the arms are pivoted to one another at a point substantially between their normally upper ends and their lower ends which constitute the jaws for engagement with the workpiece.
  • the jaws are provided with tapered tips 8 effective to bite into the ingot sides and lessen the risk of accidental release during hoisting.
  • Two secondary arms 9 and 10 have their lower ends secured by way of pivots 12 and 14 to arms 2 and 4 and have both their upper ends pivoted to a yoke 16 by which the tongs can be secured to the hook or sling of a suitable lifting crane. In use, hoisting produces lifting of the tongs as a whole while causing the jaws 8 to close upon and grip a workpiece located between them.
  • a latch mechanism is provided to automatically maintain the jaws in the open position to receive a workpiece and subsequently automatically to release the jaws for closure.
  • the latch mechanism comprises a member 20 secured to arm 4 by way of a pivot 21 and having a profiled opening 22 terminating at its upper end in a substantially linear guide portion 24, which although shown open-ended may be closed off.
  • a projection 26, which may be in the form of a fixed spigot or a roller mounted upon primary arm 2 is arranged to be received within the opening 22 and to slidably move cyclically around its periphery.
  • the projection 26 With the jaws in the closed position as shown in FIG. 2, either engaging a workpiece or otherwise, the projection 26 will lie at the upper end of the guide portion 24.
  • the length of the guide portion 24 is selected to be sutficient to accommodate the excursion of the spigot 26 for any particular degree of closure which is limited by an abutment 36 provided on arm 4 and arranged for engagement with arm 2.
  • the center of gravity of the member 20 is selected such that at this stage it is in a first equilibrium position whereby further downward movement of the projection relatively to the opening 22 automatically allows the member to tilt for engagement of the projection with a re-entrant portion 32 of the opening periphery (see FIG. 3).
  • the shape of the re-entrant portion is effective to prevent disengagement while the weight of the tongs is supported solely by the yoke 16 and prevents closure of the jaws 8.
  • a successive and independent upward thrust against the arms 2 and 4 by re-lowering of the tongs against the supporting surface reopens the jaws to release the workpiece, if originally held. Reopening continues the cyclic movement of the spigot around the periphery of the opening 22 to the lowermost point 34 (see FIG. 4); further closure when this point is reached being prevented by an additional abutment 28.
  • the member 20 is moved into its second equilibrium position by reaction between the projection 26 and the profile of the opening 22 so that with further closure of the jaws produced by lifting of the tongs, the portion 40 of the channel profile is urged against the projection 26. This enables the projection to continue and complete its cycle to the top of the guide portion 24 without re-engagement with portion 32.
  • the tongs are now ready for a further cycle of operation in response to successive forces applied to arms 2 and 4.
  • the crane which hoists the automatic lifting tongs of the invention is controlled from a cabin often at considerable height above the ground level.
  • a suitable indicator may be provided on the tongs. This may be of any type well known in the art, for example a pointer arm, which conveniently is constituted by an extension of the linear guide portion 24 of the latch member 20.
  • tongs have been described as provided with jaws in the form of tapered tips, any form of jaw adapted to engage with different types of workpieces, for example, barrels, planks, sacks, not necessarily connected with the steel industry, may be used.
  • the crane hook is fitted with an attachment or is adapted, as is well known, to prevent release of the tongs if these are excessively lowered.
  • FIG. 5 shows an alternative latch mechanism in the same position as the latch mechanism of FIG. 4.
  • the alternative latch operates on substantially the same principle except that an auxiliary latch 50 is provided in place of the re-entrant portion 32.
  • the latch 50 is pivoted at 51 and biased in a counter clockwise direction by a spring 52 against a stop 53.
  • the pivoted latch member 20 is moved by cam reaction with the projection 26 in exactly the same way as the preceding embodiment but a spring 54 is provided in an overcenter arrangement to assist in biasing the latch member 20 to its equilibrium positions.
  • the spring 54 is compressed between a stop 55 mounted on the arm 4 and a stop 56 formed on the far end of an opening 57 in the latch member 20, within which the spring 54 is located.
  • the position of the over-center spring in the other equilibrium position is shown at 58 in broken outline.
  • Lifting tongs comprising:
  • said latch mechanism mounted on said primary arms, said latch mechanism including a latch member having an internally profiled opening pivotally mounted on one of said arms and a projection rigidly mounted on the other of said arms, said projection being retained in and co-operating with said opening;

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Load-Engaging Elements For Cranes (AREA)
US93698A 1969-12-02 1970-11-30 Automatic lifting tongs Expired - Lifetime US3697118A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5889969 1969-12-02

Publications (1)

Publication Number Publication Date
US3697118A true US3697118A (en) 1972-10-10

Family

ID=10482644

Family Applications (1)

Application Number Title Priority Date Filing Date
US93698A Expired - Lifetime US3697118A (en) 1969-12-02 1970-11-30 Automatic lifting tongs

Country Status (8)

Country Link
US (1) US3697118A (enrdf_load_stackoverflow)
JP (1) JPS4935375B1 (enrdf_load_stackoverflow)
BE (1) BE759705A (enrdf_load_stackoverflow)
CA (1) CA941860A (enrdf_load_stackoverflow)
DE (1) DE2058858A1 (enrdf_load_stackoverflow)
FR (1) FR2073445B1 (enrdf_load_stackoverflow)
GB (1) GB1326743A (enrdf_load_stackoverflow)
NL (1) NL7017584A (enrdf_load_stackoverflow)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4106612A (en) * 1976-09-24 1978-08-15 Mbi Corporation Gripper for case unloader
US4545722A (en) * 1983-05-04 1985-10-08 Westinghouse Electric Corp. Flexible robot gripper for irregular shapes
US5666758A (en) * 1995-06-07 1997-09-16 Vaillier, Deceased; George Louis Retrieval mechanism
US6012752A (en) * 1999-02-24 2000-01-11 Douglas; William E. Concrete pipe lifting apparatus
US6123376A (en) * 1997-01-27 2000-09-26 Notsuunso Kabushikikaisha Load clamping and lifting apparatus
ES2162600A1 (es) * 2000-04-03 2001-12-16 Talleres Ojeda S L Pinza para elevacion de bloques de hormigon.
US20040135389A1 (en) * 2003-01-09 2004-07-15 Helms Robert J. Lifting device for manhole tops and manhole covers
US20080036229A1 (en) * 2006-08-14 2008-02-14 Marc Oliason Variable diameter lifting tongs
US20110008146A1 (en) * 2009-07-09 2011-01-13 R&S Systems, Llc Method and Apparatus for Lifting Cumbersome Articles
US20110227356A1 (en) * 2008-01-31 2011-09-22 Bac Industries, Inc. Brush remover
CN102862913A (zh) * 2012-09-29 2013-01-09 浙江荣峰起重机械制造有限公司 一种自动开闭夹具
US8528951B1 (en) * 2010-10-26 2013-09-10 Karl R. Aberth Folding reach extender
CN103771262A (zh) * 2014-01-21 2014-05-07 天津格林兰机械装备有限公司 自动开合式钢管吊钳
US9022443B1 (en) 2010-10-26 2015-05-05 Karl R. Aberth Folding reach extender
CN105936473A (zh) * 2016-06-15 2016-09-14 盐城丰东特种炉业有限公司 一种自装卸吊钩装置
US10111412B1 (en) * 2017-10-24 2018-10-30 Roland G Hebert Fish culling clip
CN109279500A (zh) * 2018-11-27 2019-01-29 新乡市豫新起重机械有限公司 一种用于圆形物体装卸使用的吊钳及起重机
US20220194748A1 (en) * 2020-12-21 2022-06-23 Kenneth Brandon HOMEWOOD Lifting clamp

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2374253A1 (fr) * 1976-12-17 1978-07-13 Creusot Loire Tenaille pour la manutention de charges
CH605389A5 (enrdf_load_stackoverflow) * 1977-05-17 1978-09-29 Kueng Hans
FR2611823B1 (fr) * 1987-03-03 1989-04-14 Noirot Yves Dispositif de verrouillage et deverrouillage
FR2752232A1 (fr) * 1996-08-08 1998-02-13 Batiment Et De Construction Cb Dispositif pour accrocher un fardeau a une grue ou similaire
JP5890134B2 (ja) * 2011-09-16 2016-03-22 渡辺建設株式会社 吊り上げ装置およびこれを用いた工法
JP2014136816A (ja) * 2013-01-16 2014-07-28 Olympus Corp 陽極酸化処理用治具
JP2019099370A (ja) * 2017-12-08 2019-06-24 株式会社クボタ クランプ装置および管搬送車

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2337177A (en) * 1942-10-08 1943-12-21 Breslav Jack Lifting grab

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2337177A (en) * 1942-10-08 1943-12-21 Breslav Jack Lifting grab

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4106612A (en) * 1976-09-24 1978-08-15 Mbi Corporation Gripper for case unloader
US4545722A (en) * 1983-05-04 1985-10-08 Westinghouse Electric Corp. Flexible robot gripper for irregular shapes
US5666758A (en) * 1995-06-07 1997-09-16 Vaillier, Deceased; George Louis Retrieval mechanism
US6123376A (en) * 1997-01-27 2000-09-26 Notsuunso Kabushikikaisha Load clamping and lifting apparatus
US6254157B1 (en) * 1997-01-27 2001-07-03 Notsuunso Kabushikikaisha Load clamping and lifting apparatus
US6286881B1 (en) 1997-01-27 2001-09-11 Notsuunso Kabushikikaisha Load clamping and lifting apparatus
US6012752A (en) * 1999-02-24 2000-01-11 Douglas; William E. Concrete pipe lifting apparatus
ES2162600A1 (es) * 2000-04-03 2001-12-16 Talleres Ojeda S L Pinza para elevacion de bloques de hormigon.
US20040135389A1 (en) * 2003-01-09 2004-07-15 Helms Robert J. Lifting device for manhole tops and manhole covers
US20080036229A1 (en) * 2006-08-14 2008-02-14 Marc Oliason Variable diameter lifting tongs
US7673917B2 (en) * 2006-08-14 2010-03-09 Marc Oliason Variable diameter lifting tongs
US20110227356A1 (en) * 2008-01-31 2011-09-22 Bac Industries, Inc. Brush remover
US8602469B2 (en) * 2009-07-09 2013-12-10 R&S Systems, Llc Method and apparatus for lifting cumbersome articles
US20110008146A1 (en) * 2009-07-09 2011-01-13 R&S Systems, Llc Method and Apparatus for Lifting Cumbersome Articles
US9022443B1 (en) 2010-10-26 2015-05-05 Karl R. Aberth Folding reach extender
US8528951B1 (en) * 2010-10-26 2013-09-10 Karl R. Aberth Folding reach extender
US8814242B1 (en) 2010-10-26 2014-08-26 Karl R. Aberth Folding reach extender
CN102862913A (zh) * 2012-09-29 2013-01-09 浙江荣峰起重机械制造有限公司 一种自动开闭夹具
CN103771262A (zh) * 2014-01-21 2014-05-07 天津格林兰机械装备有限公司 自动开合式钢管吊钳
CN103771262B (zh) * 2014-01-21 2015-10-14 天津格林兰机械装备有限公司 自动开合式钢管吊钳
CN105936473A (zh) * 2016-06-15 2016-09-14 盐城丰东特种炉业有限公司 一种自装卸吊钩装置
US10111412B1 (en) * 2017-10-24 2018-10-30 Roland G Hebert Fish culling clip
CN109279500A (zh) * 2018-11-27 2019-01-29 新乡市豫新起重机械有限公司 一种用于圆形物体装卸使用的吊钳及起重机
US20220194748A1 (en) * 2020-12-21 2022-06-23 Kenneth Brandon HOMEWOOD Lifting clamp
US12269713B2 (en) * 2020-12-21 2025-04-08 Kenneth Brandon HOMEWOOD Lifting clamp

Also Published As

Publication number Publication date
NL7017584A (enrdf_load_stackoverflow) 1971-06-04
FR2073445B1 (enrdf_load_stackoverflow) 1978-01-13
BE759705A (fr) 1971-05-17
DE2058858A1 (de) 1971-06-09
JPS4935375B1 (enrdf_load_stackoverflow) 1974-09-21
GB1326743A (en) 1973-08-15
FR2073445A1 (enrdf_load_stackoverflow) 1971-10-01
CA941860A (en) 1974-02-12

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