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US3773377A - Lifting clamps - Google Patents

Lifting clamps Download PDF

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Publication number
US3773377A
US3773377A US00241209A US3773377DA US3773377A US 3773377 A US3773377 A US 3773377A US 00241209 A US00241209 A US 00241209A US 3773377D A US3773377D A US 3773377DA US 3773377 A US3773377 A US 3773377A
Authority
US
United States
Prior art keywords
link
radius
housing
pressure foot
pressure
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.)
Expired - Lifetime
Application number
US00241209A
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English (en)
Inventor
V Kopp
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.)
Cooper Industries LLC
Original Assignee
MERRIL BROTHERS
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
Application filed by MERRIL BROTHERS filed Critical MERRIL BROTHERS
Application granted granted Critical
Publication of US3773377A publication Critical patent/US3773377A/en
Assigned to STUDEBAKER-WORTHINGTON, INC. reassignment STUDEBAKER-WORTHINGTON, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MERRILL BROTHERS, INC.
Assigned to EDISON INTERNATONAL, INC. reassignment EDISON INTERNATONAL, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: STUDEBAKER-WORTHINGTON, INC., A CORP. OF DE
Assigned to COOPER INDUSTRIES, INC., 1001 FANNIN, HOUSTON, TEXAS 77002, A CORP. OF reassignment COOPER INDUSTRIES, INC., 1001 FANNIN, HOUSTON, TEXAS 77002, A CORP. OF ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: EDISON INTERNATIONAL, INC., A CORP. OF DELAWARE
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • B66C1/42—Gripping members engaging only the external or internal surfaces of the articles
    • B66C1/44—Gripping members engaging only the external or internal surfaces of the articles and applying frictional forces
    • B66C1/48—Gripping members engaging only the external or internal surfaces of the articles and applying frictional forces to vertical edge portions of sheets, tubes, or like thin or thin-walled articles

Definitions

  • a lifting clamp comprises a housing having fixed and movable jaws positioned to grip and hold loads of varying thickness therebetween.
  • the movable jaw or cam as it is sometimes referred to in the art, is actuated by a link and lever connection to a radius link pivotally mounted on said housing, which said link is also connected to means such as a crane for applying lifting force to the clamp to lift the load, the leverage being such that the greater the lifting force required to lift the load, the greater the gripping force applied to the load by the movable jaw.
  • the radius link can be moved to open or close the jaws by a hand lever pivotally mounted on said housing, and means are provided for applying spring pressure to said radius link to lock said movable jaw in open position, and in various closed positions depending on the thickness of the load.
  • This invention relates to lifting clamps having fixed and movable jaws between which a load to be lifted may be securely gripped.
  • the loads lifted by such clamps are sometimes of great weight, frequently several tons, and are sometimes lifted to considerable heights. If the load slips from the clamp there is danger of serious damage to personnel and to equipment and property. It is of paramount importance, therefore, that the load be gripped securely by the clamp at all times, i.e. from the time when it is first gripped until it is intentionally released from the clamp.
  • the possibility of accidental or unintended release must be reduced to a minimum, particularly at times when the load is being deposited on a supporting surface or member, at which time it may be subjected to jolting or other stresses tending to loosen or release the grip.
  • clamps are widely used as plate clamps for lifting heavy steel plates and slabs'which may vary in thickness from about 0.25 inch to 4 inches or inches or even more.
  • a satisfactory clamp must be capable of gripping loads having a wide range of thicknesses.
  • FIG. 1 is a bottom plan view of the clamp looking toward the jaws in which the movable jaw is in open position.
  • FIG. 2 is a side elevation.
  • FIG. 3 is a section on the line 3-3 of FIG. 2 in which the movable jaw is in open position.
  • FIG. 4 is a section on the line 4-4 of FIG.2 in which the movable jaw is in closed position to clamp a relatively thick load.
  • FIG. 5 is a side elevation partly in section and partly broken away in which the movable jaw is in closed position to clamp a relatively thin load.
  • FIG. 6 is a section on the line 6--6 of FIG. 5.
  • the clamp shown in the drawings is of the type known as a plate clamp designed and adapted for lifting heavy steel plates. It will be understood, however, that the lock device of the invention may be applied to other types of clamps in which a load is gripped between jaws.
  • the clamp comprises a housing having parallel side plates 1, 2 spaced apart by blocks 3, 3 and connected in any suitable manner'as by rivets or bolts (not shown).
  • a slot 4 is formed'in each of the side plates of sufiicient width to receive a load 5 of the maximum thickness for which the clamp is designed.
  • the formation of the slot provides two depending legs 6 and 7 in the housing plates.
  • the legs 6 which carry a serrated gripping pad 8 mounted in the block 3 constitute the fixed jaw of the clamp.
  • the other leg 7 carries the movable jaw 9 which is pivotally mounted on the. pivot pin 10 which extends through the side plates 1, 2.
  • the movable jaw has a serrated gripping surface 1 1 which is curved eccentrically with respect to the axis of pivot pin 10 in accordance with common practice in the art.
  • the movable jaw 9 is pivotally connected to the ends of links 12 by the pin 13, with the other ends of said links pivotally connected by pin 18 to a lifting shackle 14 adapted to be engaged by the hook 15 of a crane or other lifting equipment.
  • a radius link 16 is pivotally mounted on the housing by pin 17 and has arms extending in opposite directions from the pivot. One arm is pivotally connected near its end to the links12 and shackle 14 by the pin 18.
  • Pin 17 is mounted to rotate on the plates 1, 2.
  • the radius link pivots freely on the pin 17, but the lever link 19 and hand lever 20, both of which are mounted on the pin 17, are keyed thereto so that rotating movement of the hand lever 20 causes the lever link 19 to rotate in the same direction.
  • Lever link 19 is located within the housing between the plates 1, 2 but the lever 20 is located outside the housing on an extension of the pin 17 which projects beyond the plate 1.
  • Lever link 19 is pivotally connected by a pin 21 to a pressure foot 22 having a toe 23 and a heel 24.
  • Lever link 19 and pressure foot 22 constitute the two legs of a toggle joint which includes the pin 21 as its knee, the functions of which will be explained hereinafter.
  • a guide rod 25 formed integrally with the pressure foot 22 extends downwardly and into and through an aperture 26 in the pin 27 which is pivotally mounted in the plates 1, 2.
  • the guide rod 25 is slidable freely in the aperture 26 and is surrounded by a compression spring 28 one end of which bears against the pin 27 and the other end of which bears against the pressure foot 22.
  • the other arm 30 of the radius link terminates in a convexly curved surface positioned to engage the heel 24 of the pressure foot 22 in the open position of the clamp as shown in FIG. 3.
  • the radius link is also provided with a concavely curved surface 32 positioned to engage the curved surface 33 of the toe 23 in the closed position of the clamp as shown in FIGS. 4 and 5.
  • the clamp is shown with the movable jaw in closed position in gripping engagement with the load.
  • the hand lever 20 is moved in counterclockwise direction causing the lever link 19 to move in counterclockwise direction.
  • the axis of pin 21 moves overcenter, i.e. it passes the line A connecting the axes of pins 17 and 27, and as it continues its movement, the surface 33 of the toe 23 moves toward and engages the curved surface 32 of the radius link.
  • the heel of the pressure foot 22 has moved away from the arm 30, thus freeing the radius link to swing in counterclockwise direction when the surface 32 is engaged by the surface 33.
  • the spring 28 now exerts pressure on the radius link through the pressure foot 22 causing the radius link to swing in counterclockwise direction. This movement, in turn, acting through links 12, causes the movable jaw to grip the load.
  • the lever link 19 and pressure foot 22, being pivotally connected by the pin 21, constitute a toggle joint which becomes effective in the closed position of the clamp, so that the pressure applied to the radius link by the spring 28 acting through the pressure foot 22 is very great, and becomes greater and greater as the axis of pin 21 moves across and away from the line A connecting the axes of pins 17 and 26 and thus increases the angle between the legs of the toggle joint.
  • FIG. 4 the clamp is shown in closed position with the parts shown gripping a relatively thick load.
  • FIG. 5 the clamp is also shown in closed position but with the parts shown gripping a load of lesser thickness.
  • the angle between the legs of the toggle joint has increased to an extent such that the axes of the three pivot points are nearly aligned.
  • the compression of the spring 28 may decrease somewhat as the axis of pin 21 moves away from the line A connecting the axes of pins 17 and 27, it will be understood that the toggle joint compensates for the decreased compression of the spring.
  • the arrangement is preferably such that the axes of the three pivot points of the toggle joint are brought substantially into alignment by operation of the hand lever when the movable jaw is swung into contact with the gripping pad 8.
  • the clamp is capable of gripping and lifting loads of a very wide range of thickness.
  • the hand lever 20 When the lifting operation has been completed, and it is desired to release the clamp from the load, the hand lever 20 is swung in clockwise direction to the position of FIG. 5. Again, as the pin 20 moves overcenter, the spring pressure causes the pressure foot to snap over and to hit the radius link with considerable force. This force as transmitted to the movable jaw is usually sufi'icient to release the stuck jaws from the load.
  • a lifting clamp comprising a housing having fixed and movable jaws between which a load may be clamped, a radius link pivotally mounted on said housing, said radius link having arms extending in opposite directions from the pivot, means including a link pivotally connecting one arm of said radius link to said movable jaw to move said jaw between open and closed positions, a spring, and means to transmit pressure from said spring to one arm of said radius link when said link is in jaw opening position and to transmit pressure from said spring to the other arm of said link when said link is in jaw closing position.
  • a lifting clamp as claimed in claim 2 in which said pressure foot is provided with a guide rod, a pin pivotally mounted on said housing and having an aperture therein to receive said rod in sliding relation thereto,
  • a lifting clamp as claimed in claim 2 including a lever link pivotally mounted on said housing on an axis concentric with the axis of said radius link, said lever link being pivotally connected to said pressure foot.
  • a lifting clamp comprising a housing having fixed and movable jaws between which a load may be clamped, a radius link pivotally mounted on said housing, said radius link having arms extending in opposite directions from the pivot, means for connecting one arm of said radius link to said movable jaw to move said jaw between open and closed positions, a toggle joint comprising a lever link pivotally mounted on said housing on an axis concentric with the axis of said radius link and constituting one leg of the toggle joint and a pressure foot pivotally connected to said lever link and constituting the other leg of the toggle joint, and means to apply spring pressure to said toggle joint to cause said pressure foot to engage and apply pressure to one arm of said radius link in one position of said toggle joint and to cause said pressure foot to engage and apply pressure to the other arm of said radius link in another position of said toggle joint.
  • a lifting clamp as claimed in claim 5 including a hand lever pivotally mounted on said housing on an axis concentric with said radius link and said lever link and operatively connected to said lever link to move said toggle joint from one position to another.
  • a lifting clamp as claimed in claim 5 in which said pressure foot is provided with a guide rod pivotally connected to said housing, said rod being in sliding engagement with the pivot, and in which one end of said spring bears against said pivot and the other end of said spring bears against said pressure foot.
  • a lifting clamp as claimed in claim 7 in which said pivotal connection between said lever link and said pressure foot lies on one side of a line connecting the axis of said lever link pivot with the axis of said rod pivot in one position of said toggle, and passes over center to lie on the other side of said line in another poness of the load which is gripped.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Load-Engaging Elements For Cranes (AREA)
US00241209A 1972-04-05 1972-04-05 Lifting clamps Expired - Lifetime US3773377A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US24120972A 1972-04-05 1972-04-05

Publications (1)

Publication Number Publication Date
US3773377A true US3773377A (en) 1973-11-20

Family

ID=22909715

Family Applications (1)

Application Number Title Priority Date Filing Date
US00241209A Expired - Lifetime US3773377A (en) 1972-04-05 1972-04-05 Lifting clamps

Country Status (9)

Country Link
US (1) US3773377A (it)
JP (1) JPS5211984B2 (it)
AT (1) AT328133B (it)
AU (1) AU454511B2 (it)
BE (1) BE794785A (it)
CA (1) CA962304A (it)
CH (1) CH558298A (it)
FR (1) FR2178855B1 (it)
IT (1) IT974012B (it)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492401A (en) * 1983-06-14 1985-01-08 J. C. Renfroe And Sons, Inc. Non-marring lifting clamp
US4498699A (en) * 1982-10-29 1985-02-12 J. C. Renfroe And Sons, Inc. Lifting clamp locking mechanism with push button release handle
EP0424602A1 (de) * 1989-10-27 1991-05-02 SIEGERT & CO. GMBH & Co. Klemme für Blechtransport
US20090139156A1 (en) * 2007-11-29 2009-06-04 Thomas & Betts International, Inc Fast beam clamp
US20090218836A1 (en) * 2008-03-03 2009-09-03 Cooper Brands, Inc. Plate Lifting Clamp
CN111003631A (zh) * 2019-12-12 2020-04-14 杨俊玲 一种用于薄板吊装的水平吊钳

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5298052A (en) * 1976-02-12 1977-08-17 Hitachi Ltd Mold for injection molding
NL8003800A (nl) * 1980-07-01 1982-02-01 Stamicarbon Werkwijze en inrichting voor het spuitgieten van kunststoffen.
JPS59189596A (ja) * 1983-04-11 1984-10-27 日立照明株式会社 螢光灯電子点灯回路
JPS63237920A (ja) * 1987-03-26 1988-10-04 Nissei Plastics Ind Co 射出成形金型
FR2614886B1 (fr) * 1987-05-07 1989-08-18 Langloy Charles Pince pour la manutention et le levage de toles, plaques ou similaires
JPH0191515U (it) * 1987-12-08 1989-06-15

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3297354A (en) * 1966-04-11 1967-01-10 Renfroe & Sons J C Lifting clamp
US3507534A (en) * 1968-12-30 1970-04-21 Merrill Brothers Plate lifting clamp with automatic release mechanism

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3297354A (en) * 1966-04-11 1967-01-10 Renfroe & Sons J C Lifting clamp
US3507534A (en) * 1968-12-30 1970-04-21 Merrill Brothers Plate lifting clamp with automatic release mechanism

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4498699A (en) * 1982-10-29 1985-02-12 J. C. Renfroe And Sons, Inc. Lifting clamp locking mechanism with push button release handle
US4492401A (en) * 1983-06-14 1985-01-08 J. C. Renfroe And Sons, Inc. Non-marring lifting clamp
EP0424602A1 (de) * 1989-10-27 1991-05-02 SIEGERT & CO. GMBH & Co. Klemme für Blechtransport
US20090139156A1 (en) * 2007-11-29 2009-06-04 Thomas & Betts International, Inc Fast beam clamp
US8038106B2 (en) 2007-11-29 2011-10-18 Thomas & Betts International, Inc. Fast beam clamp
USRE45825E1 (en) 2007-11-29 2015-12-22 Thomas & Betts International Llc Fast beam clamp
US20090218836A1 (en) * 2008-03-03 2009-09-03 Cooper Brands, Inc. Plate Lifting Clamp
US7819448B2 (en) 2008-03-03 2010-10-26 Cooper Brands, Inc. Plate lifting clamp
CN111003631A (zh) * 2019-12-12 2020-04-14 杨俊玲 一种用于薄板吊装的水平吊钳

Also Published As

Publication number Publication date
JPS5211984B2 (it) 1977-04-04
AU4922072A (en) 1974-05-23
ATA170873A (de) 1975-05-15
DE2309502A1 (de) 1973-10-11
AT328133B (de) 1976-03-10
CH558298A (de) 1975-01-31
IT974012B (it) 1974-06-20
JPS4914854A (it) 1974-02-08
BE794785A (fr) 1973-05-16
CA962304A (en) 1975-02-04
FR2178855B1 (it) 1977-09-30
AU454511B2 (en) 1974-10-31
FR2178855A1 (it) 1973-11-16
DE2309502B2 (de) 1976-04-15

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Legal Events

Date Code Title Description
AS Assignment

Owner name: COOPER INDUSTRIES, INC., 1001 FANNIN, HOUSTON, TEX

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:EDISON INTERNATIONAL, INC., A CORP. OF DELAWARE;REEL/FRAME:004475/0595

Effective date: 19851031