US3929242A

US3929242A - Vertical lift cranes

Info

Publication number: US3929242A
Application number: US493871A
Authority: US
Inventors: Edward C Sawyer
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-02-20
Filing date: 1974-08-02
Publication date: 1975-12-30
Anticipated expiration: 1992-12-30

Abstract

Lifting and transporting apparatus comprising a pair of spaced cranes each having a boom pivoted at the lower end for swinging to and from a substantially vertical position. A load-supporting member is suspended from the upper end of each boom and is adapted to support one end of a load between the cranes. The boom is held in a position such that its upper end from which the load-supporting member is suspended is disposed within the area of ground engagement of the crane, and preferably substantially at the center of ground engagement. A tow bar on each crane is adapted to be connected to the load.

Description

United States Patent 1 Sawyer Dec. 30, 1975 [54] VERTICAL LIFT CRANES [22] Filed: Aug. 2, 1974 [21] Appl. No.: 493,871

Related US. Application Data [63] Continuation-in-part of Ser. No. 333,475, Feb. 20, 1973, abandoned, which is a continuation-in-part of Ser. No. 186,620, Oct. 5, 1971, abandoned.

[52] US. Cl. 214/390; 212/9; 214/1 P; 2l4/D1G. 3; 305/34 [51] Int. Cl. B60P 3/42 [58] Field of Search. 214/390, 620, DIG. 3, DIG. 4, 214/1 P, 1 PL; 212/46 R, 46 A, $9,144, 8 R, 9; 305/34, 51; 152/333 1,966,428 7/1934 Brown 152/333 2,337,074 12/1943 Walker 2,394,217 2/1946 Tom 3,645,559 2/1972 Stafford 214/390 X Primary ExaminerRobert G, Sheridan Attorney, Agent, or Firm-Whittemore, Hulbert & Belknap [57] ABSTRACT Lifting and transporting apparatus comprising a pair of spaced cranes each having a boom pivoted at the lower end for swinging to and from a substantially vertical position. A load-supporting member is suspended from the upper end of each boom and is adapted to support one end of a load between the cranes. The boom is held in a position such that its upper end from which the load-supporting member is suspended is disposed within the area of ground engagement of the crane, and preferably substantially at the center of ground engagement. A tow bar on each crane is adapted to be connected to the load.

US. Patent Dec. 30, 1975 Sheet 1 of2 3,929,242

Sheet 2 of 2 US. Patent Dec. 30, 1975 VERTICAL LIFT CRANES REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my application Ser. No. 333,475 filed Feb. 20, 1973, now abandoned, which was a continuation-in-part of my application Ser. No. 186,620 filed Oct. 5, 1971, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION This invention contemplates the use of two cranes in a manner which enables the lifting of substantially greater loads than heretofore considered possible.'The maximum weight that a single crane can lift is limited because the boom normally extends upward at an angle to the vertical outside the radius of the base or support at ground level. Any crane will tip over if its maximum load is exceeded because of this relationship of the boom to the supporting base.

I have found that by utilizing two such cranes with the boom of each positioned so that the upper end from which the load is suspended is within the area of the base of the crane, and preferably at the center of the base, substantially greater loads can be lifted safely. The cranes thus support the load between them at points within the area of the base so as to eliminate the danger of tipping.

In the prior art, the cranes of which I am aware all are subject to the danger of tipping because the reaction to the lifting force falls outside the radius of the base and accordingly their maximum load limits must not be exceeded.

One object of this invention is to provide lifting and transporting apparatus comprising a pair of spaced cranes each having a pivoted boom provided with a load-supporting member at the upper end, holding each boom so that its load-supporting member is within the area of the base, and suspending a load between the cranes. The cranes may be used both to lift the load between them and to move the load from one place to another.

Another object is to provide a lifting and transporting apparatus in which special pneumatic tires are provided for the cranes.

Another object is to provide the cranes with tow bars which may be connected to the load when it is moved from place to place.

Other objects and features of the invention will become apparent as the following description proceeds, especially when taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a side elevational view showing two cranes supporting a load between them, in accordance with my invention. One of the cranes is shown in its entirety and the other is only fragmentarily shown.

FIG. 2 is a front elevational view of one of the cranes.

FIG. 3 is a fragmentary longitudinal sectional view of a pneumatic tire of modified construction.

FIG. 4 is similar to FIG. 1 but shows the booms in a different position.

Referring now more particularly to the drawings, and especially to FIGS. 1 and 2, there is shown in FIG. 1 two cranes supporting a load L in the form of a tube between them. The cranes are identical in construction.

Each crane 10 comprises a supporting or base structure 12. The supporting base structure comprises a frame 14 having the generally horizontal side members 16 to the ends of which are connected the transverse front and rear axles 18. Wheels 20 mounted on the axles 18 support the endless tracks 22 having track elements 22a which support the crane on the ground. The cranes are preferably of the track-laying type which provide a broad area of support to sustain the extremely heavy loads contemplated. Additional rollers 24 are mounted on the supporting base structure to support the tracks between wheels 20. Any suitable means such as motor 21 may be provided to drive the wheels 20 and hence move the crane over the terrain.

Heavy duty pneumatic tires T are provided on both tracks 22. Each tire is a continuous elongated tubular member which extends over a track 22 to provide pneumatic support throughout the full length thereof. The tires may be secured upon the tracks 22 by any suitable means and preferably the track elements 22a are formed with laterally spaced radially outwardly extending flanges 22 which confine the opposite sides of the tire .in the same manner that the flanges on an automobile wheel rim confine the tire sidewalls.

The use of the heavy duty pneumatic tires distributes the weight of the crane uniformly over the entire area of ground support. The steel track elements 22a if used without tires would bear unequally on the ground particularly when traveling over high spots or uneven terrain. Because of the extremely great weight involved, an unequal distribution of the forces could easily break one of the track elements 22a or some other part of the ground-supporting structure. By uniformly distributing the weight through the use of pneumatic tires, the concentration of forces is eliminated and hence much greater loads can be lifted without danger of breaking the equipment. The track structure and related elements will also have a longer life when used with pneumatic tires.

FIG. 3 shows a modified tire construction. The top and bottom walls of the tire T in FIG. 3 are designated a and b respectively. The interior of the tire is subdivided by longitudinally spaced] transverse partitions 0 into separate compartments d. The length of the compartments is not critical, but there should be a multiplicity of them, preferably of equal length, throughout the circumferential extent of the tire. These compartments are sealed from one another by the partitions and separately inflated by valve means not shown. The compartmented tire construction makes it possible for the tire to take greater concentrations of pressure. This is important particularly in the construction of FIGS. 1 and 2 where the load is concentrated at the front of the crane. It is also important when the cranes move over uneven terrain because high spots in the road produce greater concentrations of pressure.

The base structure has a cab 26 mounted on frame 14 by any suitable means such as the turntable 28 which permits the cab to turn on the vertical axis of center pin 29 by a suitable power source on the crane, not shown. The center pin 29 is at the center of the crane, that is atthe center of the area of ground support provided by the supporting base structure 12, particularly the tires T.

A transverse horizontal pivot shaft 34 is mounted on the front of the cab. The lower end of a boom 36 is pivoted to shaft 34. The bodm is of the gallows or open A-frame type. It includes the laterally spaced boom 3

members

33 and 35. Each boom member includes a lower plate member 37 to which is secured an upper frame member 39. The upper frame members are con nected at their upper ends by the horizontal transverse connecting member 40.

The shaft 34 on which the boom or gallows frame 36 is mounted is within the area of ground support provided by the tracks 22 so that the entire boom or gallows frame 36, when vertical, is within the radius or area of ground support of the tracks.

The transverse connecting member 40 of the boom or gallows frame 36 supports a transverse horizontal pulley shaft 41 by means of the suspension members 43. The pulley shaft 41 is thus hung between the

upright boom members

33 and 35 of the gallows frame.

A flexible linear member such as cable 42 extends from the shaft of motor 44 on the cab over pulleys 46 on pulley shaft 41 and over the pulleys 48 carried by the lifting block 50. Lifting block 50 is suspended between the

boom members

33 and 35 of the gallows frame by the cable 42. The block is connected, preferably by a removable connection, to a forwardly extending load-supporting member 52. The motor 44 drives in opposite directions to take in or pay out the cable 42 and thus either raise or lower the load-supporting member 52.

The boom or gallows frame 36 of each crane is shown in vertical position and is held in such position by back braces 53 pivoted at their upper ends at 54 to the upper ends of the

boom members

33,35 and at their lower ends at 55 to the top of cab 26. The back braces 53 may be disconnected from the cab and their lower ends secured by any suitable means to boom

members

33,35 when not in use. A flexible linear member 56 extends from the shaft of motor 58 over pulleys 60 on the supporting frame structure 62 carried by the cab and over pulleys 64 on the shaft 66. Shaft 66 is carried by arms 68 which are pivoted to the horizontal connecting member 40 at the upper end of the boom. The motor 58 is reversible to pay out or take up the cable. It is obvious that the boom may be allowed to swing away from the cab and be held in a position extending upwardly but at an angle to the vertical by disconnecting the lower ends of the back braces 53 and paying out the cable 5.6.

A tow bar B is provided for each crane. The tow bar B is an elongated member pivoted at one end of the vertical stub shaft 60 at the front end of the cab 26 for horizontal swinging. The tow bar has a nut and bolt assembly 62 at its forward end used for connecting the forward end of the tow bar to the adjacent end of the load L. The nut and bolt assembly is adapted to pass through a suitable hole in the load. The nut and bolt assembly may be replaced by any suitable means of connection to the load.

In operation, and with the two cranes spaced apart and facing one another as shown with their booms held vertically upright by back braces 53, the load-supporting members 52 are engaged with opposite ends of the load L to be lifted. The opposite ends of the load-supporting members 52 in this instance may simply extend within the adjacent ends of the load which in the example happens to be a tube. The load-supporting members 52 may be replaced by a single elongated member extending through the tubular load L and removably connected to blocks 50 of the two cranes at the ends. By taking up on cables 42 to lift the load, the reaction force on each crane is in a vertical direction from the 4 top of the vertical boom down to the supporting base. Since the boom is vertical and lies within the area of ground support of the supporting base provided by tracks 22, there is substantially no moment ofi force tending to tip the crane. Therefore, exceedingly large loads maybe lifted without the danger of tipping.

Before the cranes are moved to transport the lifted load L to another location, the tow bars should be connected to the load. This is accomplished by raising the load to approximately the elevation shown in FIG. 1 so that the tow bars may be connected thereto. The tow bars as shown are connected at their forward ends by the nut and bolt assemblies 62' to the bottom wall of the tube. The tow bars provide much better stability and unite the two cranes so that in effect they provide a single support for the load while it is being transported. The load L is kept from swinging and of course the cranes will be prevented from separating from it.

The load may be replaced on the ground simply by disconnecting the tow bars and swinging them out of the way, and paying out cables 42 to lower the supporting members 52 until the load contacts the ground.

Each crane may of course be used individually to lift loads and transfer them in a more or less conventional manner with the back braces 53 disconnected and the boom pivoted out so as to extend upwardly at an angle to the vertical.

It will be understood that the gallows frame while shown as pivoted near the front of the crane, could for greater stability be pivoted over the center pin of the crane. However, it isshown in the present instance as pivoted at the point 34 where the more conventional single element boom is normally pivoted. Obviously the gallows frame shown and described could readily be replaced by the more conventional boom of the single boom element type if desired.

FIG. 4 shows a modification of the invention. The two cranes 10' there illustrated are of substantially the same construction as the cranes 10 previously described except that their booms 36 are tilted back to the positions shown so that the suspension members 43 which support the load are as nearly as possible directly over the center pin 29. This center pin is located at the center of the area of ground support provided by the tires T. Hence the support of the load is evenly distributed over the entire area of ground support.

In FIGS. 1 and 2, on the other hand, the support of the load is near the front edge of each crane, producing concentrations of pressure which may place a heavy strain on the equipment and particularly on the tires and related supporting structure. By supporting the load at the center of the area of ground support, as in FIG. 4, the crane is more stable when moving over uneven terrain, and the pressures and strains upon the supporting structure are distributed more evenly and accordingly minimized.

The parts of the cranes 10 shown in FIG. 4 have been given the same reference characters as the cranes in FIGS. 1 and 2 although it will be noted that some of the parts are of slightly different construction or form. Thus the back braces 53 and arms 68 in FlG. 4 are somewhat shorter due to the back tilt of the booms. These braces and arms may, for example, be sectional and shortened by taking out sections. It will also be noted that the load-supporting members 52 are slightly longer than shown in FIGS. 1 and 2, again because of the back tilt of the booms.

The tires T of the cranes of FIG. 4 may, if desired, be replaced by the modified tires T of FIG. 3.

What I claim as my invention is: l. Lifting and transporting apparatus comprising a 'pair of cranes disposed in spaced relation to one another, said cranes being track-laying vehicles each having a ground engaging base and provided with endless tracks supporting the same for movement over the ground, each crane also having a boom and the cranes disposed with their booms facing one another, said boom of each crane being of the gallows or A-frame type comprising a pair of elongated laterally spaced boom members joined at their upper ends by a transverse member and pivotally supported at their lower ends within the area of ground engagement of said tracks, means holding the boom of each crane in a position extending substantially vertically upwardly within the area of ground engagement of said tracks, load-supporting means suspended from the connecting transverse member of each boom by flexible linear members to support one end of a load disposed between said cranes, means for taking in and paying out said flexible linear members to raise and lower said load-supporting means, each crane having a tow bar adapted to be releasably connected to the load, said tow bars having pivotal connections to said cranes permitting swinging movement from an operative, forwardly extended position to an inoperative position, and pneumatic tires for said endless tracks.

2. The lifting and transporting apparatus defined in claim 1, wherein said holding means includes a releasable brace member, and means operative when said brace member is released to swing said boom of each crane to an angular position spaced from the vertical so that each crane may be used independently of the other in a conventional manner.

3. Lifting and transporting apparatus comprising a pair of cranes disposed in spaced relation to one another, said cranes being track-laying vehicles each having a ground engaging base and provided with endless tracks supporting the same for movement over the ground, each crane also having a boom and the cranes disposed with their booms facing one another, said boom of each crane being of the gallows or A-frame type comprising a pair of elongated laterally spaced boom members joined at their upper ends by a transverse member and pivotally supported at their lower ends within the area of ground engagement of said tracks, means holding the boom of each crane in a position extending generally vertically upwardly within the area of ground engagement of said tracks, said transverse member of each boom being within the area of ground engagement of said tracks in said generally vertically upwardly extending position of said boom, load-supporting means suspended from the transverse member of each boom by flexible linear members to support one end of a load disposed between said cranes, means for taking in and paying out said flexible linear members to raise and lower said load-supporting means, and a tow bar on each crane adapted when in operative position to be releasably connected to the load and being movable away from operative position when not in use.

4. The lifting and transporting apparatus defined in claim 3, including pneumatic, tires for said tracks.

5. The lifting and transporting apparatus defined in claim 4, wherein each tire is an endless tubular member the interior of which is sub-divided by longitudinally spaced transverse partitions into separate, sealed fluidpressurized compartments.

6. The lifting and transporting apparatus defined in claim 3, wherein said transverse member of each boom is disposed over the crane center pin at the center of ground support. of said base.

7. The lifting and transporting apparatus defined in claim 6, including pneumatic tires for said tracks.

Claims

1. Lifting and transporting apparatus comprising a pair of cranes disposed in spaced relation to one another, said cranes being track-laying vehicles each having a ground engaging base and provided with endless tracks supporting the same for movement over the ground, each crane also having a boom and the cranes disposed with their booms facing one another, said boom of each crane being of the gallows or A-frame type comprising a pair of elongated laterally spaced boom members joined at their upper ends by a transverse member and pivotally supported at their lower ends within the area of ground engagement of said tracks, means holding the boom of each crane in a position extending substantially vertically upwardly within the area of ground engagement of said tracks, load-supporting means suspended from the connecting transverse member of each boom by flexible linear members to support one end of a load disposed between said cranes, means for taking in and paying out said flexible linear members to raise and lower said load-supporting means, each crane having a tow bar adapted to be releasably connected to the load, said tow bars having pivotal connections to said cranes permitting swinging movement from an operative, forwardly extended position to an inoperative position, and pneumatic tires for said endless tracks.

4. The lifting and transporting apparatus defined in claim 3, including pneumatic tires for said tracks.

5. The lifting and transporting apparatus defined in claim 4, wherein each tire is an endless tubular member the interior of which is sub-divided by longitudinally spaced transverse partitions into separate, sealed fluid-pressurized compartments.

6. The lifting and transporting apparatus defined in claim 3, wherein said transverse member of each boom is disposed over the crane center pin at the center of ground support of said base.