US3879077A

US3879077A - Lifting apparatus

Info

Publication number: US3879077A
Application number: US389558A
Authority: US
Inventors: Hermes George Celio
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-05
Filing date: 1973-08-20
Publication date: 1975-04-22
Anticipated expiration: 1992-04-22
Also published as: AU5932273A; IL43074A0; IT998537B; ZA735674B; DE2344137A1; CA1002906A; JPS4968452A; FR2197807B1; GB1446641A; BR7306860D0; FR2197807A1; AR198246A1

Abstract

This invention relates to apparatus adapted for use in conjunction with a crane or the like to lift articles which are placed or are to be placed in locations where the accessible line of lift is not co-operative with the centre of gravity of the article; said apparatus comprising means whereby said article may be suspended from the hook or like device on the crane with its centre of gravity in a vertical plane parallel to the vertical plane of the direction of lift and maintained in a generally stable condition throughout the lifting operation.

Description

United States Patent 11 1 1111 3,879,077

Celi 1451 Apr. 22, 1975 [54] LIFTING APPARATUS 3.341.243 9/1967 Archer 294/67 R 3.402.911 9/1968 ONeill 294/67 R X [761 memo" Hermes Gemge 3.521.924 7/1970 Wallenius o 294/67 R Waramch Ruschcunefs 3.653.486 4/1972 McLean et a1 212/49 x 201 1. New South Wales. Australia {22] Filed; Aug 1973 Primary E.\z1/111'11er.lames B. Marbert Assistant Eraminer-Johnny D. Cherry [2]] Appl- 3892558 Attorney Agent, or Firm-George F Smyth Foreign Application Priority Data 1571 ABSTRACT Sept. 5. 1972 Australia 331/72 This invention relates apparatus adapted for use in conjunction with a crane or the like to lift articles 52 US. Cl. 294/67 R; 294/67 A which are placed or are 19 be Placed in locations 51] Int. Cl. B66c 1/00 Where the accessible line of lift is not CO-Opermive 53 i f Search H 294/ 7 R 7 AS 7 AA with the centre of gravity of the article; said apparatus 294 7 7 73 8| 2 2 4 49 comprising means whereby said article may be suspended from the hook or like device on the crane with 5 References Cited its centre of gravity in a vertical plane parallel to the UNITED STATES PATENTS vertical plane of the direction of lift and maintained in I 058 8/1916 M f 717/49 a generally stable condition throughout the lifting op- 211' C 1.344.659 6/1920 Sjoberg 212/49 12466524 8/1923 Folland ct al. 294/67 R 34 Claims, 6 Drawing Figures LIFTING APPARATUS This invention relates to lifting apparatus and more particularly to apparatus adapted for suspension from a crane hook for the purposes of lifting and placing articles in situations where normal lifting apparatus cannot be used.

Present known methods used in the construction of high rise buildings involve the use of a lifting device usually recognized by the trade name "Portaform. In the construction of, for example. an office block, the builders first lay the initial floor and then form the walls. Once this has been done it is necessary to place shuttering or form tables at the height of the ceiling of that level. The ceiling and the floor of the next level is then formed on top of the shuttering.

It is well known in the art that floors and ceilings formed in concrete are not capable of bearing any substantial load from some days after their initial curing time. It is usually necessary therefore to leave the shuttering in place until at least 3 or 4 days have lapsed. Once this period has lapsed. the shuttering is usually removed from the level by the use of the Portaform" which comprises two parallel spaced members connected by a web at one end thereof and adapted to be suspended from a crane hook by a device which is capable of maintaining an equilibrium betweenn the respective ends of the Portaform. The Portaform" is placed in position by the crane so that one member is beneath the main supports of the shuttering and the other member is above the shuttering and the ceiling or floor formed thereon. The jacks supporting the shuttering are then released and the weight is taken by the device suspended from the crane. The crane operator then removes the shuttering from the level on which it was located to place it on the top of the ceiling formed thereby. This lifting device is generally defective in that it is not possible to use it in situations where a crane hook cannot be placed above the center of gravity of the article to be lifted.

It is an object of the present invention to provide a lifting device that is substantially free from these'defccts.

Notwithstanding any other forms which may fall within its scope the invention will hereinafter be described in three forms together with variations thereof by way of reference to the accompanying drawings of which:

FIG. 1 is a side elevation of a lifting apparatus constructed in accordance with the invention;

FIG. 2 is a side elevation of the apparatus of FIG. 1 showing the apparatus in an operational condition;

FIG. 3 is a side elevation of another form of the invention;

FIG. 4 is another illustration of the apparatus of FIG. 3 showing the functional relationship of some of the components; and

FIGS. 5 and 6 are side elevations of another form of the invention.

Referring first to FIG. 1 which shows one form of the invention comprising a first member 6 which is adapted at its upper end 7 to be attached to a crane hook or the like (not shown).

The member 6 is elongate in form and adapted to be slidably received in a channel 8 in a second member 9. At the upper end of member 9 is a tie bar 10 which contains the member 6 within the channel 8.

The member 9 is L shaped and the outer end of the right angular portion 11 is adapted to be attached to any one of a number of different types of load bearing attachments such as for example platform 12 (shown in broken lines).

The lower outermost corner portion of portion 11 has a trunion block 13 attached which is pivotally connected to a counter balance arm 14 which is connected by intermediate means such as wire rope 15 to the 10 lower end 16 of the member 6. The wire rope 15 may be attached at any convenient point along the length of the arm 14 according to the type of use the apparatus is to be put to.

In use the apparatus is suspended by 7 from a crane- 15 hook and a load applied to 12. As the crane starts its lift member 6 slides axially from 9 pulling on the cable 15 until the arm 14 reaches an angle at which an equilibrium between the load and the arm 14 is achieved. Continued lifting by the crane will then lift the load which will be maintained in a substantially stable condition.

In the no load condition the arm 14 will be at rest at about 5 from vertical. as shown in FIG. 1 while at its complete angularly displaced position (maximum load 25 condition) it will be at about 85 from the vertical.

These angles of course will vary according to the dimensional configuration of the apparatus. Such variations may be as great as 5 in the no load position and 10 in the full load position. The arm 14 should not however come to rest in the 0 position.

During a lifting operation with loads of say 10 tons the displacement efficiency of the rope 15 will deteriorate after about 30 movement of the arm 14. For this reason it is preferable that the rope 15 be attached to the end 17 of the arm 14 and a variable ratio attachment fitted.

This variable ratio attachment comprises a chariot 18 adapted to move along the arm 14 and comprising frame 19, pulley 20 and guide members 21 and clevis 22 to which one end of a progressive ratio cable 23 is attached.

The opposite end of the cable 23 passes through a pulley block 24 at the upper end 25 of the arm 14 and is then attached to the end 16 of member 6. Thus as member 6 pulls on cable 15 to lift the arm 14 it also pulls on cable 23 moving the chariot 18 along the arm 14 towards the end 25 thereby changing the leverage point progressively during the establishment of the equilibrium between the counter balance arm and the load. This condition may be more clearly seen from FIG. 2 which shows the arm 14 approaching the 55 position during a lift.

As it reaches the 55 position from the vertical the efficiency of the angular displacement action of the cable 15 once again deteriorates. In this position therefore a high ratio lift device 26 takes over and displaces the arm 14 to the required angle between the 55 and 85 positions.

This high ratio device 26 may comprise a slotted member 27 mounted on a pivot pin 28 which is secured to the end 25 of the arm 14. The member 27 is connected to the end 16 of the member 6 by means of a link or rope 29 so that when the arm 14 reaches the 55 position the bottom of the slot 30 in the member 27 engages the pin 28 to take the weight of the arm 14 and continue to move it toward the position. This action in effect changes the point of leverage on the arm 14 thereby providing a more efficient counter balancing effect.

Alternatively the high ratio lift device may comprise a wire rope, a chain or an articulate linkage connected between the member 6 and the counter balance arm. The main feature of the high lift device is that its movement is idle for about the first 40 of the movement of the arm 14 and is engaged to take over from the rope or intermediate member 15 for about the last of the arms angular movement.

The chariot rope 23 passes through the pulley block 24 and under a first pulley 31 on the member 9 from where it passes over a second pulley 32 on the end 16 of member 6 and over a third pulley 33 on member 9 to return to an anchor on 16. This compound pulley system ensures that the chariot moves a substantial distance along the arm 14.

Complete return of the chariot 18 to its rest position near the end 17 of the arm 14 is achieved by means of a return spring 34 and draw bar 35. As the arm passes through the 50 position on its upward motion the chariot engages a clevis bar 36 at the upper end of the draw bar 35 thereby tensioning the spring 34 during further movement towards the 85 position. Thus the arm returns to the 50 position on its downward motion the return spring 34, draw bar 35 and clevis bar 36 pull the chariot 18 back towards the end 17. As the arm 14 passes the 50 position gravity takes over and allows the chariot 18 to fully return.

At the end 17 of the arm 14 is a frame 37 which is adapted to receive additional counter balance weights as required according to the type of load to which the apparatus is applied. The frame 37 also carries a set of wind reaction flaps 38 which function to assist in stabilizing the apparatus during lifting operations.

The arm 14 is also equipped with a jockey wheel assembly 39 for assistance at ground level.

Item 40 is another example of the many different types of load bearing members which may be used with the apparatus.

FIG. 3 shows another form of the invention in which the

members

6, 9 and 11 are substantially the same as those of FIGS. 1 and 2. This form of the invention is adapted for lifting greater loads than that of FIGS. 1 and 2 and differs in the construction of the counter balance arm 40. This arm 40 comprises three

separate parts

41, 42 and 43. The first part 41 which is pivotally connected to 11 at 13 has a bracket 44 near its lower end 45 and rollers 46 and 47. The bracket 44 and roller 47 serve a guide and retainer for the second part 42 at the upper end of which is a second frame 48 having an extended portion 49 with

rollers

50, 51 which run on 41.

At the lower end of arm 42 is a third guide bracket 52 and

rollers

53, 54 which function to guide the third part 43 which carries at its lower end the frame 37 and jockey wheel assembly 39. At the upper end of part 43 is a guide roller assembly 55 which runs on part 42.

In the no load position the arm 40 lies at an angle of about l5 from the vertical dependent of course on the dimensional characteristics of the various components.

As shown in FIG. 4 the low ratio cable 15 is attached to the bracket 57. Another cable is connected between

brackets

55 and 57 and passes over pulley 56.

In addition to cable 15 a second cable 58 is provided which is connected by way of a four pulley system 59 between the bottom portion 60 of member 9, bracket 48 on part 42, and an anchor point 61 on part 41.

In use, with a load applied to 11, as the crane begins the lift the member 6 by means of cable 15 angularly moves the arm 40 thereby effectively reducing the distance between anchor 61 and portion 60 and slackening rope 58 sufficiently to permit

parts

42 and 43 to extend under gravity until an equilibrium is achieved between the eounter balance arm weight and the load.

If an extremely heavy load is being lifted it may be necessary to move the arm 40' to the 85 position. In this case as the arm reaches the 60 position and the

parts

42 and 43 are fully extended the high ratio lift device 26 takes over and continues the angular displacement of the arm 40' to the point of equilibrium. If required. of course, additional balance weights may be attached to the frame 37.

The form of the invention shown in FIGS. 5 and 6 has a two part counter balance arm 62 comprising a first part 63 which is connected to a second part 64 by a pivotal connection 65. Mounted on the part 64 adjacent the connection 65 is a bracket 66 which carries a jockey wheel assembly 67 and a pulley 68 and the rope 15 extends from the end 16 of the member 6 along the arm under the pulley 68 to terminate at an anchor connection on the frame 37.

In the no load condition the arm 62 is disposed at a rest position about 5 from the vertical. When a load is being lifted the crane pulls on a member 6 which moves axially with respect to member 9 pulling on cable 15 to angularly displace part 63 with respect to part 64 until an equilibrium between the counter balance arm and the load is achieved permitting the load to be lifted.

With a heavier load, when the part 63 reaches a position at about 95 to the part 64 and when the part 64 reaches a position at about 60 from the vertical, the high ratio device 26 takes over. As the high ratio device 26 moves part 64 beyond the 60 position the tension on rope 15 is relaxed permitting the angle between the

parts

63 and 64 to decrease until part 63 is either axially aligned with part 64 or an equilibrium is achieved. At its maximum stroke the arm 62 will be at about an angle from the vertical.

It will be appreciated by those skilled in the art that the apparatus substantially as hereinbefore described may be used successfully in many difficult situations to lift articles which cannot be directly lifted by a crane or the like.

What I claim is:

1. Lifting apparatus adapted to be used in conjunction with a crane or the like, said apparatus comprising a first member adapted at one end to be vertically suspended from the crane, a second member mounted on said first member for longitudinal movement thereon and including means adapted to support an article to be lifted which has its center of gravity spaced from the accessible line of lift, counterbalance arm means pivotally connected atone end thereof to the end of said second member remote from said one end of said first member, and intermediate means connecting the said first member to said counterbalance arm means; said counterbalance arm means, said first member, said second member, and said intermediate means being so arranged, disposed, and interconnected as to provide for positive angular placement of said counterbalance arm means with respect to the weight of said article to be lifted and the effort imparted by said crane whereby said article is maintained in a generally stable position during the lifting operation.

2. Lifting apparatus as in claim 1. wherein said counterbalance arm means comprises an elongate member.

3. Lifting apparatus as in claim 1 wherein said support means comprises a load bearing member.

4. Lifting apparatus adapted to be used in conjunction with a crane or the like to lift an article which is placed or is to be placed in a position where its center of gravity is spaced from the accessible line of lift, said apparatus comprising a first member adapted to be vertically suspended from said crane, a second member mounted on said first member for longitudinal movement thereon, said second member including means adapted to support an article to be lifted, counterbalance arm means pivotally connected at one end to the lower end of said second member and connected to said first member by a low ratio displacement member, a high ratio displacement member connected between said counter-balance arm means and said first member; the working inter-relationship between said first member, said second member, said counter-balance arm means, said low ratio displacement member, and said high ratio displacement member being such that said counter-balance arm will automatically be displaced angularly through a predetermined range of movement with respect to the weight of the article to be lifted, its own gravitational pull, and the effort imparted by the crane during the initial part of the lifting action whereby said counter balance arm means will seek a point of equilibrium so that said article will be maintained in a substantially stable condition during the remainder of the lifting action.

5. Apparatus as in claim 4 wherein said counterbalance arm means comprise an elongate member pivotally connected at one end thereof to said second member and is adapted for angular displacement in the vertical plane of said apparatus.

6. Apparatus as in claim 5 wherein said low ratio displacement member comprises a flexible element connected at one end to said first member and at the other end to a point near the free end of said elongate member, said element being adapted to angularly displace said elongate member with respect to the degree of relative movement members. said first and second member.

7. Apparatus as in claim 5 including an abutment means on said elongate member and wherein said high ratio displacement member comprises an articulate device connected at one end to said first member and at the other end to said elongate member near the pivotal connection thereof to said second member, said high ratio displacement member being so arranged and disposed as to engage with said abutment means at a predetermined angular displacement position of said elongate member to change the point of leverage therefore during a further range of movement.

8. Lifting apparatus adapted for use in conjunction with a crane or the like to lift an article which is placed or is to be placed with its center of gravity spaced from the accessible line of lift, said apparatus comprising a first member adapted to be suspended from the crane, a second member mounted on said first member for relative movement therewith and adapted to support an article to be lifted, a counterbalance arm mounted on said second member, low ratio lift means connecting said counterbalance arm and said first predetermined range of angular movement with respect to the weight of the article to be lifted and the effort imparted by said crane, high ratio lift means connected between said arm and said first member adapted to engage cooperative means on said arm at the end of said first range of movement and move said arm through a second predetermined range of movement, the degree of movement of said arm being dependent on the leverage required by said arm to maintain an equilibrium between said counterbalance arm and the article to be lifted.

9. Apparatus as in claim 8 including means for progressively changing the point of leverage of said low ratio lift means during its range of movement.

10. Apparatus as in claim 7 wherein said low ratio lift means comprises cable connected to the extremity of said arm.

11. Apparatus as in claim 10 wherein said means for progressively changing the point of leverage comprises a chariot mounted on said counterbalance arm and containing said cable and means for moving said chariot along said arm with respect to the degree of movement of said arm in said first predetermined range of movement.

12. Apparatus as in claim 11 wherein said arm is pivotally mounted on said second member and said means for moving said chariot comprises rope and pulley means mounted between said first and said second members and said chariot whereby relative movement between said first and second members shortens or lengthens said rope thereby moving said chariot toward or away from the pivoted end of said arm.

13. Apparatus as in claim 12 including means biasing said chariot towards the end of said arm distal from its pivotal mounting.

14. Apparatus as in claim 13 wherein said biasing means comprise spring and draw bar means.

15. Lifting apparatus adapted to be used in conjunction with a crane or the like for lifting articles which are placed or are to be placed with their center of gravity spaced from the accessible line of lift, said apparatus comprising a first member adapted to be suspended from the crane, a second member adapted to be mounted on said first member for movement relative thereto and including means adapted to support an article to be lifted, a first counterbalance arm part pivotally attached to one of said members, a second counterbalance arm part pivotally attached to the free end of said first part, first intermediate means connected between said second member and the free end of said second part and adapted to move said second part through a first predetermined range of angular movement, second intermediate means connected between said first member and said second part adapted to move said first part and said second part through a second range of predetermined angular movement relative to each other.

16. Apparatus as in claim 15 including means adapted to progressively change the relative angular motion of said second part with respect to the first part during the relative motion of both said parts through said second range of movement.

17. Apparatus as in claim 16 wherein said first intermediate means comprises a flexible element.

18. Apparatus as in claim 11 wherein said first intermediate means comprise a wire rope.

19. Apparatus as in claim 18 wherein said means for progressively changing the relative angular motion between said parts comprise a jockey pulley mounted on the end of said first part adjacent said second part to contain said rope.

20. Lifting apparatus adapted to be used in conjunction with a crane or the like to lift an article which is placed or is to be placed with its center of gravity spaced from the accessible line of lift. said apparatus comprising a first member adapted to be vertically suspended from the crane. a second member adapted to be mounted on said first member for longitudinal movement relative thereto, said second member being adapted to support the article to be lifted, at least one counterbalance mass attached to said second member and. at least one intermediate means interconnecting said first member and said counterbalance mass for controlling the angular displacement of said counterbalance mass relative to said second member with respect to the weight of the article to be lifted and the effort imparted by the crane to maintain an equilibrium between said mass or masses and said article.

21. Lifting apparatus adapted to be used in conjunction with a crane or the like comprising a first member adapted to be suspended from the crane, a second member mounted on said first member for movement relative thereto including means for supporting an articlc to be lifted. counterbalance means pivotally connected to one of said first and second members and including an arm having a plurality of parts connected for relative extensible movement. and intermediate means interconnecting the other of said first and second members and said counterbalance means to provide for positive angular displacement of said counterbalance means relative to the weight of the article to be lifted and the effect imparted by the crane.

22. Apparatus in claim 21 including means controlling the extent of the extensible movement of said plurality of parts with respect to the angular placement of said arm.

23. Apparatus as in claim 22 wherein said means controlling the extensible movement of said plurality of parts comprises a rope and pulley system so arranged and disposed that the rope progressively slackens as the angle of displacement of said counterbalance means increases, thereby permitting said plurality of parts to progressively extend with respect to each other.

24. Apparatus as in claim 21 wherein said intermediate means comprises cable means extending from said first member to the extreme one of said plurality of parts. a substantial portion of said rope passing over reefing pulleys mounted on each of the others of said plurality of parts.

25. Apparatus as in claim 24 wherein said intermediate means is adapted to move said counterbalance means progressively through a first range of movements. said apparatus further including additional means adapted to become operative at the end of said first range of movement to move said counterbalance means through a second range of movement with re spect to the weight of said article and the effort imparted by the crane.

26. Apparatus as in claim 21 including counterweight receiving means at the end of said counterbalance means.

27. Apparatus as in claim 21 wherein said plurality of parts are serially connected by pivot means to one another.

28. Apparatus as in claim 21 wherein said pluality of parts are angularly displaceable with respect to each other and with respect to said article.

29. Apparatus for lifting an article having its center of gravity spaced from the accessible line of lift comprising means for suspending the apparatus from a crane or similar device, means mounted on said suspending mcans for longitudinal movement relative thereto for supporting the article to be lifted, counterbalance means pivotally fastened to said supporting means. and counterbalance control means interconnecting said counterbalance means and said suspending means for controlling the angular position of said counterbalance means and said supporting means in accordance with the weight of the article being lifted.

30. The apparatus of claim 29 wherein said counterbalance control means comprises first means for controlling the angular position within a first range of angular positions and second means for controlling the angular position within a second range of angular positions.

31. The apparatus of claim 29 wherein said counterbalance control means includes means for progressively changing the point of leverage on said counterbalance means as the angular position is altered.

32. The apparatus of claim 29 wherein said counterbalance means comprises a plurality of serially interconnected parts.

33. The apparatus of claim 32 wherein the parts of said plurality of parts are relatively extensible as said angular position is altered.

34. The apparatus of claim 32 wherein the parts of said plurality of parts are pivoted to one another for relative movement as said angular position is altered.

k l l l

Claims

1. Lifting apparatus adapted to be used in conjunction with a crane or the like, said apparatus comprising a first member adapted at one end to be vertically suspended from the crane, a second member mounted on said first member for longitudinal movement thereon and including means adapted to support an article to be lifted which has its center of gravity spaced from the accessible line of lift, counterbalance arm means pivotally connected at one end thereof to the end of said second member remote from said one end of said first member, and intermediate means connecting the said first member to said counterbalance arm means; said counterbalance arm means, said first member, said second member, and said intermediate means being so arranged, disposed, and interconnected as to provide for positive angular placement of said counterbalance arm means with respect to the weight of said article to be lifted and the effort imparted by said crane whereby said article is maintained in a generally stable position during the lifting operation.

4. Lifting apparatus adapted to be used in conjunction with a crane or the like to lift an article which is placed or is to be placed in a position where its center of gravity is spaced from the accessible line of lift, said apparatus comprising a first member adapted to be vertically suspended from said crane, a second member mounted on said first member for longitudinal movement thereon, said second member including means adapted to support an article to be lifted, counter-balance arm means pivotally connected at one end to the lower end of said second member and connected to said first member by a low ratio displacement member, a high ratio displacement member connected between said counter-balance arm means and said first mEmber; the working inter-relationship between said first member, said second member, said counter-balance arm means, said low ratio displacement member, and said high ratio displacement member being such that said counter-balance arm will automatically be displaced angularly through a predetermined range of movement with respect to the weight of the article to be lifted, its own gravitational pull, and the effort imparted by the crane during the initial part of the lifting action whereby said counter balance arm means will seek a point of equilibrium so that said article will be maintained in a substantially stable condition during the remainder of the lifting action.

20. Lifting apparatus adapted to be used in conjunction with a crane or the like to lift an article which is placed or is to be placed with its center of gravity spaced from the accessible line of lift, said apparatus comprising a first member adapted to be vertically suspended from the crane, a second member adapted to be mounted on said first member for longitudinal movement relative thereto, said second member being adapted to support the article to be lifted, at least one counterbalance mass attached to said second member and, at least one intermediate means interconnecting said first member and said counterbalance mass for controlling the angular displacement of said counterbalance mass relative to said second member with respect to the weight of the article to be lifted and the effort imparted by the crane to maintain an equilibrium between said mass or masses and said article.

21. Lifting apparatus adapted to be used in conjunction with a crane or the like comprising a first member adapted to be suspended from the crane, a second member mounted on said first member for movement relative thereto including means for supporting an article to be lifted, counterbalance means pivotally connected to one of said first and second members and including an arm having a plurality of parts connected for relative extensible movement, and intermediate means interconnecting the other of said first and second members and said counterbalance means to provide for positive angular displacement of said counterbalance means relative to the weight of the article to be lifted and the effect imparted by the crane.

22. Apparatus as in claim 21 including means controlling the extent of the extensible movement of said plurality of parts with respect to the angular placement of said arm.

24. Apparatus as in claim 21 wherein said intermediate meAns comprises cable means extending from said first member to the extreme one of said plurality of parts, a substantial portion of said rope passing over reefing pulleys mounted on each of the others of said plurality of parts.

25. Apparatus as in claim 24 wherein said intermediate means is adapted to move said counterbalance means progressively through a first range of movements, said apparatus further including additional means adapted to become operative at the end of said first range of movement to move said counterbalance means through a second range of movement with respect to the weight of said article and the effort imparted by the crane.

29. Apparatus for lifting an article having its center of gravity spaced from the accessible line of lift comprising means for suspending the apparatus from a crane or similar device, means mounted on said suspending means for longitudinal movement relative thereto for supporting the article to be lifted, counterbalance means pivotally fastened to said supporting means, and counterbalance control means interconnecting said counterbalance means and said suspending means for controlling the angular position of said counterbalance means and said supporting means in accordance with the weight of the article being lifted.