DE1937274A1 - Telescopic boom for a crane - Google Patents

Description

The invention relates to a telescopic boom on the turntable of a crane, which extends from the turntable extends at an angle to the perpendicular, wherein the boom has at least one sub-section, an intermediate section and a third portion mounted together for relative telescopic movement, and wherein the Subsection is mounted on said turntable, with a device for extending and contracting the Boom sections and having a main boom hoist rope assembly extending generally between the turntable and the outer end of the boom at an acute angle the boom extends.

In cranes according to the prior art, a boom is in an angular position by ropes or the like. kept that up extend from an anchor point on the turntable support structure to the top of the boom. To this

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Way the boom is prevented from getting under Bend load; so it can be made so that it is not excessively heavy. It is desirable to make these booms as light as possible for the loads to be handled, and not just from the point of view of the Economic efficiency in manufacture and transport and handling, but also in terms of their lifting capacity for any given boom size.

It is desirable to replace the boom hoist rope system to avoid hand between the anchorage point and the outer end of the boom when the length of the Boom is changed, and it is desirable to keep the boom substantially constant. Devices according to prior art to accomplish this have been suggested and use automatic balancing Rope systems.

The invention effects an extendable boom with three or more sections and an automatically compensating one Cantilever lever rope system between the anchoring point and the outer end of the boom, which is also a correct one Creates tension in the entire rope system. With the invention, the outer end of the boom is always from the anchoring point supported and the boom angle can remain substantially constant regardless of the length to which the boom is extended and at the same time the length and therefore the

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Tension of the individual carrier ropes to the boom section S can be adjusted individually in order to achieve a correct rope tension in the entire system. Thus the boom can be provided with the exact ^{amount of support 1} required at any point along its length. A uniform tension over the entire cable system can be created in this way and thus any "weak link" in the system can be avoided.

Specifically, the entire leveling jib hoist rope includes;} Stein a single suspension rope for each boom section, and each rope can be made of such a length that a uniform tension in the entire boom hoist rope system is achieved, and at the same time a essential straight alignment of the boom is maintained.

Further features and advantages of the invention emerge from the following description and the attached schematic Drawings of an embodiment of the inventive concept. Show it

Fig. 1 is a more or less schematic side view Type of an extendable boom according to the invention, the boom in its retracted Position is shown mounted on a truck chassis,

FIG. 2 is a more or less schematic view of part of the boom according to FIG. 1 with the boom

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in partially extended position, with certain parts to increase the clarity of the drawing " tion are broken away or shown removed and the entire view compared to the scale of Fig. 1 is enlarged,

3 shows a more or less schematic perspective View of the boom lifting cable system according to FIGS. 1 and 2,

Fig. 4- is a view similar to Fig. 2, but in which the individual suspension ropes are shown set in a different position,

FIG. 5 is a view similar to FIG. 2, but in which the individual suspension ropes are shown in different individual positions to one another, and

Fig. 6 is a view similar to Fig. 1, but showing a modification of the manner in which the suspension ropes are pulled around the pulley and anchored, and still a modified one Embodiment of the drive device for extending a section.

The boom B according to the invention can be on different Vehicles, loading decks or other stationary or 'movable means of support may be used, but for purposes of illustration According to the invention, it is shown on a turntable 1 of a crane truck 2. The turntable has a vertical one

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rigid part 3 and the usual mechanical winches 4- and 5> which are attached to it.

The boom may have three or more telescopic sections, and for purposes of illustrating the invention, a boom arm having four sections is shown. The sections are pushed into one another and can be extended or retracted, whereby they or the like into one another in suitable roles. (not shown) in a known manner. In the working position, the boom usually extends upward from the turntable λ at an angle to the perpendicular and is often several hundred feet long when it is extended. So that the boom can lift maximum loads, especially when the boom angle to the earth is small, the boom should be as light as possible in its weight, so that the boom weight itself does not limit the load capacity of the boom, of course in accordance with the required load capacity. ■

The load rope 7 extends from the mechanical winch 4- , and over the jib tip sheave 8 at the other end of the boom and the load, not shown, is attached, for example, to the load hook 9 at the end of the load rope 7 (Fig. 1).

The boom has a subsection 10 that is rotatable is arranged for vertical swing on a bearing pin 11 which is attached to the turntable. The Aus

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casual also has an intermediate section 12 which can slide telescopically in section 10, a third section 14,
which can slide telescopically in the intermediate section 12, and a fourth section 16 which is telescopic in the section
14 can slide and extends outward where the pulley 8 is rotatably mounted in the tip of the boom.

Means are provided for telescoping and contracting the boom sections. This device for achieving extension and contraction of the boom can be of various types and is here
in Fig. 1 only briefly as a double-acting hydraulic
Cylinder and piston device 20 shown, or in Fig. As a chain and sprocket device 20a, which is arranged between the sub-section and the intermediate sections
is to cause relative movement between these parts. The relative movement between the other sections 12 and 14 and 16 is achieved by flexible means 22 and 23 arranged between the sections 10-, 12 and 14 and between the sections 12, 14 and 16.

For the purposes of description, however, this means per se can be of any conventional and known form, such as an additional hydraulic cylinder and piston assembly, and it is not necessary to go into this further.

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In the context of the invention, a novel boom pulley system S created to hold the boom of adjustable length, making it unnecessary to to adjust the system by hand if the length of the boom is to be changed and it is desired, approximately maintain the same boom angle.

This automatically compensating boom pulley system S generally extends between the anchoring point on the turntable, which point is the f Idle pulley 3a is on the turntable and in the outer end of the boom, such as at 25. With this The system keeps the outer end of the boom away from the anchoring point held regardless of the length of the boom and the boom angle can be substantially constant stay.

The system comprises a boom hoist rope 29 and its pulley rope device 29a, which are connected to the winch 5 is and is pulled over the idle pulley 3a, and extends forward from there for attachment to a disk 30. Additional disks 32 and 34 are provided, and since they are all equal, it is sufficient to describe one from within. In the system according to the invention, as they As clearly shown in Fig. 6, the disk device is comprised of a pair of disks rotatably mounted on the shaft

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shown. Such a disk device is for each boom from section 10, 12 and they are generally adjacent to their corresponding boom section, but. at a distance upwards. In this way you d; st one Series of disc assemblies 30, 32 and 34- provided, respectively one for boom sections 10, 12 and 14.

The outer portion 16, commonly referred to as the boom tip, does not require such Disc system.

Each boom section 10, 12 and 14- also has corresponding disk devices 40, 42 and 4-4, which at or are rotatably mounted in the vicinity of their outer or front end. While the term pulley is used here for- purposes in the description of the invention "includes this Expression also disks, balls, drums or the like ..

As shown in Fig. 6, the disc assembly for each boom section consist of a pair of pulleys, one at each end of a shaft, which in turn is arranged at the end of the section.

Individual suspension cables 50, 52 and 54- are provided, one for each set of the pulley assembly and pulley assemblies 30, 40; 32, 4-2; and 34-, 44.

The tether 29, the series of disk assemblies 30,32 and 34- and parts of the rope 50, 52 and 54 together form one

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Main boom hoist rope assembly CM, which are generally from the anchoring point 3a to the jib tip 25 and in extends at an acute angle to the boom B.

The suspension cables thus extend from the main cable assembly CM and a cable is connected to its corresponding boom section by being looped around its corresponding boom section sheave. In this way the suspension ropes act to individually hold their respective boom section, as is clear from Ä

is apparent from the description. The tension in each rope can can also be adjusted to equalize the tension in the entire cable system.

The suspension cables are anchored at their lower or rear ends to the adjacent telescopic boom section. For example, ropes 50, 52, and 54- are in FIG Anchored near the rear ends of the boom sections 12, 14 and 16 at anchor points 12a, 14a and 16a.

The ropes 50 and 52 are at their upper and front | Ends at the next disc assembly outward along the Cantilever anchored, namely the disc assemblies 32 and The rope 54 is at its front end at the top of the Boom, anchored approximately at 25, in the arrangement according to Fig. 1-5.

In the arrangement of FIG. 6, the ropes 50, 52 and also passed around disks on disk assemblies 32, 34 and 36 and then extend rearward where they are placed on the

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Shafts of the disk assemblies 30, 32 and 34 are anchored. Thus, in the arrangement according to FIG. 6, there is an additional disk arrangement 36 at the outermost section 16 is used. An additional mechanical advantage is achieved when the ropes so anchored, like in Pig. 6 shown.

Usually ropes 50 »52 and 54 · are stronger Length for any boom type or length, with the ropes an additional stretch for the rope device CM form when the boom is extended and vice versa.

The present system enables individual adjustment the tension in each suspension rope and individual and adjustable Supporting effects for the boom sections .. In this way, charging characteristics can be different Kind for the different boom sections at different Loading conditions are created. This adjustment is achieved in the following way:

The length of the ropes 50, 52 and 54 can be compared to that in FIG Fig. 1 shown length can be changed. When the ropes are all shortened, as shown for example in Fig. 4, lie the disk assemblies 30, 32 and 34 more directly above, i.e., stronger in perpendicular orientation with respect to their respective pulleys 40, 42 and 44. As a result, act the ropes more at right angles to their boom sections and thereby create a greater lifting effect on or With support for their respective sections.

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_v Venn it is desirable to prevent the lifting effect between the various ropes, pulleys to one another can be moved in opposite directions, if desired, individually in the ratio. For example, in FIG. 5 the pulley arrangement 30 has been shifted to the rear or to the left of the pulley 40 by extending the cable 50. On the other hand, the pulley arrangement J4 has been shifted forwards, ie to the right, from its pulley 44 by shortening the suspension rope 54-. Accordingly the rope has a 52 g larger lifting moment, because it acts as the ropes 50 54- vein stronger at a right angle to the boom.

In this way the length of the suspension ropes can be changed for each particular crane construction, thereby changing the spacing between their disk assemblies and, accordingly, the amount of offset displacement between their end of a pulley arrangement and its corresponding pulley on the adjacent boom section. To this Way can the support effect of a suspension rope can be selectively adjusted on its boom section.

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Claims (6)

ent ans j r iich e 1. Telescopic boom extending from the turntable of a crane extends at an angle to the perpendicular, thereby characterized in that the boom has at least one base section (10), an intermediate section (12) and one third section (14) which are mounted together for relative telescopic movement, and the base section (10) the turntable (1) is mounted, with a device for extending and retracting the boom sections and a boom lifting cable system with a main boom hoist rope assembly extending generally between the turntable (1) and the outer end of the boom extends at an acute angle to the boom, and the system also has a Has a series of tethers (50,52,54) extending from the main boom hoist rope assembly extend, and wherein a tether with «pthe boom section for individual support the same is connected. 2. Boom according to claim 1, characterized ei without t that the boom hoist rope device a Has a series of disk assemblies (30.4-0; 32.4-2; 34.4A), one (40 or 4-2 or 4-4) thereof generally in the Close but spaced a distance upward from each section is, with a sheave assembly on and near the outer end of a minor section, and each - 909885/1228 the tethers move away from its corresponding pulley assembly extends from and guided over the corresponding pulley assembly to the adjacent boom section and then is anchored to the telescopic section adjacent to the rear. 5. Boom according to claim 2, characterized in that each of the tethers also extends from their respective pulley assembly over which it is guided outwardly along the boom to the next Λ pulley assembly for connection therewith, whereby an automatically compensating boom lifting cable system is formed will. 4 ·. Boom according to claim 3> characterized that the length of the holding ropes can be changed, thereby increasing the distance between the disk assembly to change and, accordingly, the value of the lateral displacement between any sheave assembly and its associated sheave assembly on the adjacent | Boom section, whereby the corresponding holding effect a tether can be changed on its boom section. 5. Telescopic boom on the turntable of a crane, the extends from the turntable at an angle to the perpendicular, with the boom at least one subsection ^ 909885/12 26 has an intermediate section and a third section mounted together for relative telescopic movement, and wherein the sub-section is mounted on said turntable with means for extending and contracting the boom sections and with a main boom hoist rope assembly generally located between the Turntable and the outer end of the boom extending at an acute angle to the boom, characterized in that that the boom hoist rope assembly comprises a series of sheave assemblies spaced along the rope assembly, and wherein a sheave arrangement generally adjacent to but spaced above each section, and with a pulley arrangement, mounted on and near the outer end of each section with a series of Tether ropes, one tether extending from each pulley assembly extends and leads over the corresponding sheave assembly on the adjacent boom section and is then anchored to the rearwardly adjacent telescopic section, in order to thereby hold each one individually To create boom section. 6. Boom according to claim 5 »dadurch-, geke.nnzeich.net, that some of the tethers also extend from their corresponding disc assembly over the 909885/1226 the rope is routed and routed outwardly along the boom to the nested pulley assembly for connection therewith, whereby an automatically compensating boom lifting cable system is formed » 7. Outrigger according to claim 6, characterized in that the length of the holding ropes can be changed, us thereby changing the section between the washer arrangement and accordingly the value of the lateral displacement between any desired sheave arrangement and its corresponding sheave arrangement on the adjacent boom section, whereby the Holding effect of a tether can be changed on its boom section. 909885/1226 ■ 4b .. Blank page