Concentric Ring Segment Supported Lift Crane

This invention relates generally to lift cranes and more particularly concerns a mobile concentric ring supported crane.

In response to ever-increasing user needs, self-propelled cranes have been made capable of lifting ever greater loads. While a number of factors enter into determining crane capacity, a basic limitation arises from the fact that, inevitably, the weight of the crane and its load must be transferred to the earth in some stable fashion and, if rotation of the load is desired, the crane-earth connection must be made stable through the arc of crane rotation.

A significant increase in crane capacity was achieved by providing a self-propelled crane with the support ring and extended boom carrier disclosed and claimed in U.S. Pat. Nos. 3,485,383; 3,878,944; and 4,196,816. In these designs, the weight of the crane and its load is transferred to the ground through a large diameter, track-like ring. As shown in these patents, and as practiced commercially for some years, the support ring is either blocked into place by timbers fitted and wedged beneath and completely around the ring or is supported by a plurality of jacks spaced around the periphery of the ring.

Further refinements in ring supported cranes are disclosed in U.S. Pat. Nos. 4,042,115 and 4,103,783 and copending U.S. applications Ser. Nos. 058,284 and 058,285, both filed July 17, 1979. These patents and applications disclose inter alia that a separate transporter mechanism may be run in and out of an otherwise stationary ring supported crane in order to move that crane between different locations or transporter mechanisms and/or idle crawlers or dollies may be installed beneath the ring under the boom foot and counterweight.

The primary aim of the present invention is to provide a heavy lift crane assembly having an upper structure including machine works and a counterweight pivotally mounted for horizontal movement on a ring structure with a boom and mast mounted on a boom carrier for horizontal rotation on a concentric ring segment spaced outwardly from the main ring. Also provided are means interconnecting the counterweight carrier and the boom top and traveling supports for the main ring and auxiliary ring segments, including front and rear pairs of laterally spaced crawler assemblies respectively located under the main ring under the counterweight and under the auxiliary ring segment beneath the boom carrier with means for selectively and reversibly driving the tracks to permit movement of the crane and ring segments over the ground while the boom is lifting a load.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIG. 1 is a side elevation of the concentric ring segment supported lift crane of the present invention;

FIG. 2 is a section taken substantially along line 2--2 in FIG. 1;

FIG. 3 is a fragmentary front elevation of the crane shown in FIG. 1 with a single boom illustrated in solid lines and dual booms illustrated in broken line; and,

FIGS. 4 and 5 are fragmentary side elevations, similar to FIG. 1, of two alternative embodiments of the invention.

Turning now to the drawings, there is shown in FIG. 1 the concentric ring segment supported lift crane 10 of the present invention. The crane 10 includes a rear machinery and counterweight support mechanism 11 and a front boom and mast support mechanism 12. In the illustration of FIG. 1 the machinery and counterweight support mechanism 11 includes a large diameter ring 13 supported by a substantially rectangular frame 14 on a self propelled transporter mechanism 15 substantially as disclosed in U.S. Pat. No. 4,195,740 which is hereby incorporated by reference. Suffice it to say that the ring-like track 13 is on the order of 36 feet in diameter and the lift machinery 16 and counterweight 17 are supported on a rotatable deck 18 for movement about the ring center line designated A.

The front boom and mast carrier mechanism 12 includes a carrier 20 supported by rollers 21 on a front ring segment 23 which is concentric with the axis A of the rear ring 13. The carrier 20 pivotally mounts a forwardly inclined boom 25 and a rearwardly inclined mast 26. The tip of the mast 26 is connected to the tip of the boom 25 by variable length rigging 27 which includes a multiple part line wound on a boom hoist drum 28 located on the machinery deck 18. The upper end of the mast 26 is also connected by means of a fixed length pendant or strut 29 to a gantry 30 carried on the machinery deck 18. In this way the counterweight 17 is connected to the mast top and through the rigging 27 is applied to the boom tip to counteract the moment of a heavy load.

In the configuration shown in FIG. 1 the crane 10 includes a primary lift line 32 wound on a winch drum 33 and reeved around guide sheaves 34 and 35 and a boom tip sheave 37. The boom 25 is also provided with a jib section 38 supported by guy pendants 39 and a strut 40. An auxiliary lift line 41 is wound on another drum 42 and is guided by sheaves 43 and 44 to the tip (not shown) of the jib 38.

Pursuant to the present invention the front boom support mechanism 12 is carried on one or more transporter assemblies 45 interconnected by frame elements 47 to the rear machinery transporter 15. The front transporters 45 are preferably demountable self propelled assemblies such as shown in U.S. Pat. Nos. 4,000,784 and 4,069,884 which are incorporated herein by reference. It will be appreciated that by suitably controlling the front transporter assemblies 45 and the rear machinery transporter 15 the crane 10 may be moved over the terrain in either a loaded or an unloaded condition.

In keeping with another aspect of the invention, the boom carrier 20 is rotatable on the front ring segment 23 in order to swing a load through at least a partial horizontal arc. Swinging movement may be provided through a web-like strut 48 connected to the rear machinery deck 18, and the front carrier 20 or, alternatively, the carrier 20 may be rotated on its ring segment 23 by one or more independent swing drive mechanisms such as shown in U.S. Pat. Nos. 3,949,881 and 4,013,174 which are also incorporated herein by reference.

As shown in FIG. 2, a pair of front transporter assemblies 45 are provided to support the ring segment 23. Each transporter 45 carries a pivot ring 50 on which a base plate 51 is mounted. This permits the transporter mechanisms 45 to be propelled, as disclosed in U.S. Pat. No. 4,069,884 to move in forward, reverse or turning directions (the latter being shown in broken lines). Since the transporters 45 support the ring segment 23 on which the boom carrier 20 rides, the crane 10 may move under either loaded or unloaded conditions.

According to the present invention, heavy lifts and placement of loads can also be made which require swinging the load through a substantial arcuate segment, for example 90.degree. or more. This is particularly useful in making multiple lifts of loads from a carrier, such as a ship or barge and placement of the loads on a dock or pier. Accordingly, as shown in dash lines in FIG. 2, additional concentric ring segments 23a, b and c may be attached to the primary ring segment 23, and these additional ring segments 23a, b, c, et cetera may be blocked or jacked into level position such as by the bolsters shown at 53a, b, c and d.

It will be appreciated, of course, that a single boom 25 may be supported by the front carrier 20 (as shown in solid lines in FIG. 3) or spaced-apart dual booms 25a and b may be provided (as shown in broken lines of FIG. 3). In the latter instance it is desirable to provide dual transporter mechanisms 45, while a single front transporter may be sufficient if a single boom 25 and only limited swinging of the load is contemplated for a particular lift.

Turning now to FIG. 4, another embodiment of the heavy lift crane is illustrated. As shown here, the rear lift machinery and counterweight support is substantially the same as that disclosed in copending U.S. application Ser. No. 058,284 which is incorporated by reference. Otherwise, this unit is generally similar to that shown in FIG. 1 and similar reference numerals are used for similar parts.

In FIG. 5 another embodiment is shown based on an enlarged 60 foot rear ring mounted on self-propelled transporters 15a and b (which may be single or dual units) similar to the transporter 45 in FIG. 1. The basic ring structure and machinery deck for the embodiment of FIG. 5 may be substantially the same as that disclosed in U.S. Pat. No. 4,103,783 (which is incorporated herein by reference) as modified by the addition of the transporter assemblies 15a and b. In other respects reference numbers similar to FIG. 1 are employed.

It should also be appreciated that the embodiments shown in side elevation in FIGS. 4 and 5 may employ either single or dual front transporter assemblies 45 (as shown in FIGS. 2 and 3) and either single or dual booms 25 (as shown in FIG. 3). Likewise additional concentric ring segments 23a-x (as shown in FIG. 2) may be attached and supported by blocks, bolsters, jacks or the like.

From the foregoing, it will be seen that a heavy lift crane 10 is provided utilizing a standard "Ringer" crane as the rear lift machinery and counterweight support and a front concentric ring segment for supporting the boom and mast and transmitting the load down through a self-propelled transporter assembly into the ground.