US3732988A - Jib assembly for telescoping crane boom - Google Patents

Abstract

An extensible jib assembly for a crane boom of the extensible and retractable type which has a main boom member and at least one outer boom member telescoped within the main boom member. The jib assembly consists of a plurality of rectangular jib sections with a base section telescopingly receiving the remainder of the sections. First cooperating means between the base section and the main boom member normally maintain the jib assembly in a stored position on the lower surface of the main boom member. The jib assembly is located in a manner that releasable coupling means carried by one end of the base section may be connected to the outer end of the outer boom section when the boom is fully retracted so as to pivotally connect the jib assembly to the boom while the jib assembly is in the stored position. The jib assembly is moved to an operative position by connecting one end of a cable forming part of a hand winch to the opposite end of the jib assembly and releasing the cooperating means so that unwinding of the winch will allow the jib assembly to pivot about the crane boom. The jib assembly is held in any of a plurality of angularly related operative positions on the boom through cable means having one end connected to the jib assembly and a second end connected to a mast structure extending above the free end of the outer boom member. The jib assembly may be used in a fully retracted, a partially extended and a fully extended position of the free end of the boom and may be held in a plurality of angularly related positions on the boom in each extended position.

Description

United States Patent 1 Lamer [54] JIB ASSEMBLY FOR TELESCOPING CRANE BOOM [75] Inventor:

[52] U.S.Cl .r212/l44,212/55 [51] Int. Cl. ..B66c 23/62 [58] Field of Search ..212/55, 59, 144

[56] References Cited UNITED STATES PATENTS 3,366,250 1/1968 Grove ..212/144 3,246,769 4/1966 Noll ..212/144 3,125,227 3/1964 Kauffmanm, ..212/144 3,037,641 6/1962 Potter ..212/46 A 3,306,467 2/1967 Weemde ..212/55 3,465,899 9/1969 Reuter 212/144 3,306,470 2/1967 Green ..212/144 3,464,570 9/1969 Mork 212/144 3,194,413 7/1965 Landry.... .....212/55 3,308,967 3/1967 Barkley ..212/144 FOREIGN PATENTS OR APPLICATIONS 1,247,584 8/1967 Germany ..212/46 13 154,650 10/1963 U.S.S.R. ..212/55 11] 3,732,988 1 'May 15, 1973 57 ABSTRACT tensible and retractable type which has a main boom member and at least one outer boom member telescoped within the main boom member. The jib assembly consists of a plurality of rectangular jib sections with a base section telescopingly receiving the remainder of the sections. First cooperating means between the base section and the main boom member normally maintain the jib assembly in a stored position on the lower surface of the main boom member. The jib assembly is located in a manner that releasable coupling means carried by one end of the base section may be connected to the outer end of the outer boom section when the boom is fully retracted so as to pivotally connect the jib assembly to the boom while the jib assembly is in the stored position.

The jib assembly is moved to an operative position by connecting one end of a cable forming part of a hand winch to the opposite end of the jib assembly and releasing the cooperating means so that unwinding of the winch will allow the jib assembly to pivot about the crane boom.

The jib assembly is held in any of a plurality of angularly related operative positions on the boom through cable means having one end connected to the jib assembly and a second end connected to a mast structure extending above the free end of the outer boom member. The jib assembly may be used in a fully retracted, a partially extended and a fully extended position of the free end of the boom and may be held in a plurality of angularly related positions on the boom in each extended position.

1 JIB ASSEMBLY FOR TELESCOPING CRANE BOOM BACKGROUND OF THE INVENTION The present invention relates generally to crane boom structures and more particularly to an improved jib assembly for use with such structures.

In crane boom assemblies, particularly those of the extensible type, it has become customary to provide some type of extension for the boom, commonly referred to as a jib, which adapted to be mounted on the free end of the outer boom section in order to provide additional length or height to the boom. Jibs of this type are shown in U.S. Pat. Nos. 1,920,370 and 2,772,790.

Since the majority of the jobs performed with an extensible crane do not require the jib assembly to be attached thereto, the storage of the jib assembly has become a'major problem. For example, in most instances, the jib assemblies have been stored on separate trucks when not in use. This arrangement not only requires additional equipment, but also necessitates a considerable amount of time and effort to properly assemble the jib assembly on the main boom when needed.

Recently a jib has been proposed which can be stored directly on the main boom when not in use and can be connected to the main boom when desired. Such an assembly is disclosed in Grove U.S. Pat. No. 3,366,250.

While such an arrangement has found some commercial success, the versatility of the unit of the type disclosed in the Grove patent is extremely limited. Furthermore, the construction of the jib assembly extremely limits the amount of weight which may be transferred when the jib assembly is used on the end of the main boom.

Thus, there remains a need for a jib assembly which has greater load capacity then heretofore known and which can be mounted for storage directly on the main crane when not in use.

SUMMARY OF THE INVENTION The present invention contemplates an extensible jib assembly which can be stored in a compact position directly on the main boom and can readily be extended to any one of a plurality of positions without the sacrifree of load capacities.

The jib assembly of the present invention includes three jib sections, each of a rectangular cross-sectional configuration and of a lattice construction and the sections are arranged to be telescoped within each other to produce a short, compact assembly that can be stored directly on the main crane boom when not in use.

The lattice type construction provides a high strenth to weight ratio relative to the load carried on the free end of the jib assembly and all the forces imposed on the jib sections are applied as a compressive force producing a column load on the jib assembly.

The jib assembly can readily be moved from a stored position to an operative position having any one of a plurality of lengths and can be maintained on the main boom at any one of a plurality of angularly related positions, thereby substantially increasing the versatility of the unit.

The jib assembly is specifically designed for use with an extensible boom structure having at least a main boom member and an outer boom member telescoped relative to each other with the jib assembly comprising a base section, an intermediate section and an outer end section, each of polygonal configuration with the intermediate and outer end sections adapted to be telescoped within the base section. Cooperating means between the base section and the main boom member define a stored position for the jib assemblyon the lower side of the main boom member to accommodate operation of the main boom while the jib assembly is in the stored position. The base section of the jib assembly and the free end of the outer end member further have means defining an operative position for the jib assembly in which the jib assembly extends beyond the outer end of the outer boom member. In addition, the combination further includes a simple hand-operated winch which can be utilized to move the jib assembly from its stored position to an operative position.

The means defining an operative position for the jib assembly includes a mast structure pivotally supported on the free end of the outer boom section and normally maintained in a stored condition where the mast structure extends substantially parallel to the longitudinal axis of the main boom. The mast structure can readily be pivoted to an operative position extending above the boom outer end member and cable means extending between the mast structure and the free end of the jib assembly will maintain the jib assembly in any one of a plurality of angularly related operative positions relative to the boom.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF DRAWINGS FIG. 1 of the drawings shows a crane having the jib assembly of the present invention in its stored position on the crane boom;

FIG. 2 shows the sequence of steps for moving the jib assembly from its stored to its operative position;

FIG. 3 shows the boom structure and jib assembly in their fully extended position;

FIG. 4 is a fragmentary perspective view of the jib assembly of the present invention;

FIG. 5 (appearing with FIG. 1) is an enlarged transverse sectional view taken generally along line 55 of FIG. 1;

FIG. 6 is an enlarged fragmentary view of the outer end of the boom structure;

FIG. 7 is a fragmentary enlarged plan view of the jib assembly in an extended position;

FIG. 8 is an enlarged fragmentary elevation of the connection between adjacent jib sections; and

FIG. 9 is a fragmentary side elevation of the boom and jib assembly.

DETAILED DESCRIPTION While this inventionis susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one specific embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

Referring to the drawings, and more particularly to FIG. 1, the jib assembly 10 is shown in conjunction with a vehicle 12 having a boom 14, the inner end of which is pivoted about a horizontal axis defined by a pin 16 extending between a pair of boom supports 18( only one being shown). The boom supports are carried on a turntable 20 which is supported for rotation about a vertical axis on the frame 22 of a self-propelled vehicle. The frame 22 has a plurality of extensible Outriggers 24 located at each of the corners to raise the entire frame a sufficient distance to space the wheels 26 above the ground. The boom 14 is adapted to be pivoted about the horizontal pivot axis 16 through a fluid ram 28 interposed between the supports 18 and the boom 14.

The boom 14 see FIG. 6) includes a main or inner boom member 30 and intermediate boom member 32 and an outer boom member 34. The respective boom members are constructed in a manner that the intermediate boom member is telescoped within the main boom member while the outer boom member is telescoped within the intermediate boom member and the respective boom members are adapted to be extended and retracted relative to each other by suitable fluid rams not shown).

A main winch 35 is supported on a counterweighted extension 36 extending from the supports 18 and a cable 37 extends from a drum on the winch and supports a hook block assembly 38 on the outer boom member 34.

The jib assembly of the present invention is more clearly shown in FIG. 4 and includes a base section 40, an intermediate section 42 and an outer end section 44. Each of the sections are of a polygonal or rectangular cross-sectional configuration and of lattice construction with the various parts of the respective sections being constructed and arranged so that the sections are telescopingly mounted relative to each other and movable between extended and retracted positions. For this purpose, the base section includes longitudinal corner members 46 consisting of standard angle irons interconnected by lattice or lacing members 48. Likewise, the intermediate section consists of a plurality of longitudinal corner members 50 interconnected by lattice or cross members 52. However, it will be noted from an inspection of FIG. 5 that the cross members or diagonal cross-bars 52 are located between opposed surfaces of the adjacent legs of the angle irons 50. The outer end section of the jib assembly also includes a plurality of corner members or angle irons 54 interconnected by lattice members diagonal cross-pieces 56 with the lattice members being located on the inside of the angle irons. Thus, the respective sections may readily be telescoped within each other and may be held in extended or retracted position.

In the extended position shown in FIG. 7, spaced pairs of apertures 60 defined in the outer end of the base member are aligned with apertures 62 defined on the inner end of the intermediate section of the jib assembly. A pair of pins 66 are respectively received through the aligned apertures 60 and 62 and are retained therein by a collar 68 and a collar pin 70. Likewise, the outer end of the intermediate section has spaced pairs of aligned apertures 72 which are aligned with apertures 74 adjacent the inner end of the outer section with pins 66 received through the apertures and retained therein by a collar 68 and a further pin 70. The outer ends of the base section and the intermediate section each have a support roller 80 rotatably supported on a pin 82 carried by extensions 84.

Also, the inner end of the intermediate section has a pair of extensions 90 supporting idler rollers 92 which guide the intermediate section relative to the base section during manual extension and retraction of the sectrons.

In the intermediate extended position of the jib assembly, the respective pairs of openings 60, 72 and 74 are aligned with each other and receive a pair of pins or pin means 66 to maintain the outer section extended and the intermediate section retracted. Thus, the jib assembly has a first position wherein all three of the jib sections are in a retracted position; an intermediate position where the end section is in an extended position while the base and intermediate sections are in a retracted position; and a third position where the respective sections are all in a fully extended position relative to each other.

FIGS. 1 and 5 show the manner in which the jib assembly 10 is stored on the main boom. For this purpose, the main boom has a pair of brackets secured thereto by bolts 102 with suitable spacers 104 interposed between the brackets 100 and the main boom member 30. A pair of lugs 106 are welded to the outer surface of the outer angle irons 46 and the brackets and lugs have openings 108. A pin 110 is received through each group of aligned openings and is retained therein by a collar 112 and a collar pin 114.

The storage means further includes a pair of plates fixedly secured to the outer end of the main boom member 20 with depending portions (FIG. 6) defining transversely aligned apertures. A pair of plates 122 are secured to the outer surface of the base section of the jib and have apertures which are adapted to be aligned with the apertures in the plates 120 with the apertures again receiving a pin 110. The brackets 100, lugs 106 and plates 120,122 define spaced bracket means so that the entire jib assembly 10 can be stored in juxtaposed relation to the boom by the use of the two pins 110 and will accommodate extension and retraction of the boom members 30, 32 and 34.

In order to attach the jib assembly in an operative position of the outer end of the outer boom section, the base section has a bifurcated portion defined by a pair of arms extending beyond the inner end of the base section with the arms located on opposite sides of the outer end of the outer boom member. The free ends of the arms have releasable coupling means 132 for attachment to the outer end member. For this purpose, the outer end member 34 has transversely extending pin 134 while the releasable couplings 132 are in the form of a trunion having a first half 142 fixedly secured to the ends of the arms 130 and a second half 144 adapted to be secured by the first half by bolts 145. When the jib assembly is in the stored position, the removable coupling halves 142 are removed so that that pin or cross-shaft 134 can be moved in and out of engagement with the coupling halves 140. In order to at tach the jib assembly 10 onto the main boom 14, the

main boom 14 is completely retracted so that the cross shaft 134 is located in the depressions defined in the first trunion halves 142. Thereafter, the removable halves 144 of the respective trunions are secured to the guide means 154 located adjacent the end of the jib assembly. The free end of the winch cable has clamp means 156 for releasably connecting the cable to the end of the jib assembly. The free end of the jib assembly also has a pair of wheels 162 supported thereon by a shaft 164.

The jib assembly is moved from-the stored to an operative position by attaching the clamp means 156 to the end of the jib assembly and applying sufficient tension to the winch cable 152 to take the weight off the pins 110. The pins 110 are then removed and the main boom l4is raised sufficiently to allow the jib to clear the ground when the winch cable 152 is unreeled. The hand winch is then operated to pivot the jib assembly 10 from its stored position shown in FIG. 1 to a substantially vertical or hanging position with the wheels spaced from the ground. The cable 152 is then released from the jib assembly and the main boom 14 is extended about halfway and lowered sufficiently to allow the ground engaging members or wheels 162 supported on the end of the jib assembly to touch the ground.

Subsequently, the main boom is lowered and simultaneously retracted so as to place the jib assembly in substantially end-to-end relationship with the main boom.

The main boom is then extended and lowered so as to place the jib assembly substantially parallel to the ground and suitable supports may be placed under the front end of the jib assembly to accomplish this purpose.

According to a further aspect of the present invention, the jib assembly includes cable means which are capable of holding the jib assembly 10 in any one of a plurality of angularly related positions when l) the jib assembly is fully extended; (2) when the jib assembly is in its partially extended or intermediate position; and (3) when the jib assembly is in the fully retracted position. All of this is accomplished by a small group of cables of variable lengths which may be interconnected in a manner to position the jib assembly as desired. For this purpose, the cable means 170 includes a first cable 174 having an intermediate portion cooperating with and guided around cable guide means 172 on the free end of the end jib section. The cable means 170 further includes two cables having a second length less than the length of the first cable and two cables having a length less than the second cables not shown). For example,

with a jib assembly having an 18 foot length in its fully retracted position, a 29 foot length in its intermediate position and a 40 foot length in its fully extended position, the first cable is approximately 41 feet long, the second cables are approximately 2] feet long and the third cables are approximately 2 "5 1 feet long. The respective cables have suitable clevis means 176 for interconnecting the cables or for connecting the cables to the outer boom member.

The means for attaching the cable to the main boom includes a mast structure 180 having one end pivoted at 182 on the outer end of the outer boom member with a pair of short cables 184 having opposite ends respectively connected to the outer end of the mast 180 and to the outer boom member as clearly shown in FIG. 6. Normally, the mast structure is in a collapsed condition wherein the longitudinal dimension of the mast is lobly is attached to'the outer end of the outer boom, the respective clevises 176 are attached to the upper end of the mast after the mast has been moved to its operative position where it extends above the structure.

Assuming that the jib assembly is fully extended and is to be positioned in a substantially end-to-end relationship with virtually no angular relation relative to the longitudinal axis of the boom, the two intermediate lengths of cable are attached to the opposite ends of the main cable 174 to thereby define the cable means for holding the jib assembly in the solid line position shown in FIG. 3. If it is desired to have a first angular relation relative to the main boom, the cable means length is increased by utilizing one of the two short pieces of cable which is of sufficient length to place the jib assembly in the intermediate'dotted line position shown in FIG. 3, for example at an angle of approximately 15 relative to the longitudinal axis of the main boom. If it is desired to move the jib assembly to a second angular position relative to the main boom, the second short length of cable is also attached to the main cable 174 which will locate the jib assembly in the second dotted line position shown in FIG. 3 or at an angle of approximately 30. 7

The same three angular relationships of the jib assembly relative to the longitudinal axis of the main boom can likewise be accomplished when the jib assembly is in its intermediate or partially extended position wherein the base and intermediate sectionsare in a collapsed condition and the outer end section is in the extended position. In this instance, the substantially end-to-end relation would be accomplished by utilizing a single intermediate length cable with the main cable while the first angular relation is obtained by adding a first of the two short cables to the cable means and the second angular position is obtained by adding the second short cable to the cable means. When the jib assembly is in its fully retracted operative position, the single main cable 174 is utilized for positioning the jib assembly in substantially end-to-end relation, a first section of short cable is added to obtain the first angular position while both short cables are utilized for obtaining the second angular position. Thus, the jib assembly is capable of being positioned at three angular positions relative to the longitudinal axis of the main boom in any one of its three extended and retracted positions by the use of only five sections of cable which may be appropriately interconnected to define the various cable means.

According to another aspect of the present invention the base section 40 has cable receiving means for storing the cable means when the jib assembly is in a stored position. The cable receiving means includes spaced bent rods 186 connected to a pair of the angle irons 46 and cooperating therewith to define recesses receiving the cable. The cable can. be wrapped around the respective rods and the clevises 176 can then be attached to suitable cross-braces 48. Preferably,- the cable means is stored on the bottom side of the base section when the jib assembly is in the stored position on the boom.

After the jib assembly has been positioned to the desired relation relative to the main boom, by the appropriate selection of the cables and the manual extension of the various sections relative to each other, the main hoist cable or an auxiliary cable may be threaded through the guide portions surrounding a guide pulley 190 on the end of the jib assembly and the hook block 38 may be suitably arranged relative thereto. It will be appreciated that the jib assembly may include more then three sections, if desired.

To move the jib assembly from the operative to the stored position, the procedure for erecting the jib assembly, described above, is reversed.

As can be seen from the above description, the present invention provides a simple jib assembly which is extremely versatile and which can be operated in any one of a plurality of angularly related and extended positions relative to the boom assembly while the assembly can be manually transformed into a compact unit for storage on the main boom assembly. The load to weight ratio of the jib assembly is extremely high since the majority of the load is supported by a columnar af fect of the jib assembly. Furthermore, having the intermediate portion of the cable means freely movable relative to the jib assembly insures an even loading of the cable means and all portions of the jib assembly.

What is claimed is:

1. An extensible boom structure comprising a boom of the extensible type having a main boom member and an outer boom member telescoped within the main boom member; a jib assembly including a base section, an intermediate section and an outer section telescoped within each other, each of said sections being of polygonal cross-sectional configuration and including corner members interconnected by spaced lattice cross-pieces, said cross-pieces of said base section being connected to an outside portion of said comer members, said cross-pieces of said outer section being connected to an inside portion of said corner members and said cross-pieces of said intermediate section being connected to an intermediate portion of said comer members so that said intermediate section can be telescopingly received between said base and outer sections; means defining first and second groups of apertures adjacent opposite ends of each of said sections, one group of apertures of each adjacent pairs of sections being aligned when the associated sections are in extended and retracted positions relative to each other; pin means received in the aligned apertures to retain said sections in extended and retracted positions; roller means on some of said sections accommodating extension and retraction of said sections relative to each other; a bifurcated portion on one end of said base section accommodating pivotal connection to an outer end of said outer boom member; bracket means on one side of said base section for connection to an underside of said main boom member; first means releasably mounting said base section in a stored position on said main boom member; coupling means on one end of said base section for releasably coupling said base section to the outer end of said outer boom member; said first means and coupling means being arranged so that jib assembly (1) may be stored on said main boom member while said boom is being extended and retracted and (2) form an extension of said boom by release of said first means and connection of said bifurcated portion to said outer boom member with said coupling means to accommodate pivotal movement of said jib assembly on said outer boom member; a mast pivotally supported on said outer boom member and having a stored position in juxtaposed relation to said outer boom member and an operative position extending above said outer boom member; cable guide means on the free end of said outer end section; cable means guided around said cable guide means and connected to said mast to maintain said jib assembly in an operative position when said jib assembly forms an extension of said boom, said cable means including a first cable having an intermediate portion cooperating with said cable means and a plurality of additional cables selectively attachable to opposite ends of said first cable so that the effective length of said cable means may be altered to position said jib assembly at any of a plurality of angular positions relative to said boom for each of said extended positions.

2. An extensible boom structure as defined in claim 1, further including manually operable winch means supported on said main boom member and having a winch cable extending therefrom; and guide means on said main boom member adjacent the opposite end of said base section for guiding said cable, said cable having clamp means on a free end thereof for releasable connection to said jib assembly so that actuation of said winch means accommodates pivotal movement of said jib assembly from the stored position.

3. An extensible boom structure as defined in claim 1, further including ground engaging means on the free end of said outer end section for engaging the ground during pivotal movement of said jib assembly to the operative position.

Claims (3)

1. An extensible boom structure comprising a boom of the extensible type having a main boom member and an outer boom member telescoped within the main boom member; a jib assembly including a base section, an intermediate section and an outer section telescoped within each other, each of said sections being of polygonal cross-sectional configuration and including corner members interconnected by spaced lattice cross-pieces, said cross-pieces of said base section being connected to an outside portion of said corner members, said cross-pieces of said outer section being connected to an inside portion of said corner members and said cross-pieces of said intermediate section being connected to an intermediate portion of said corner members so that said intermediate section can be telescopingly received between said base and outer sections; means defining first and second groups of apertures adjacent opposite ends of each of said sections, one group of apertures of each adjacent pairs of sections being aligned when the associated sections are in extended and retracted positions relative to each other; pin means received in the aligned apertures to retain said sections in extended and retracted positions; roller means on some of said sections accommodating extension and retraction of said sections relative to each other; a bifurcated portion on one end of said base section accommodating pivotal connection to an outer end of said outer boom member; bracket means on one side of said base section for connection to an underside of said main boom member; first means releasably mounting said base section in a stored position on said main boom member; coupling means on one end of said base section for releasably coupling said base section to the outer end of said outer boom member; said first means and coupling means being arranged so that jib assembly (1) may be stored on said main boom member while said boom is being extended and retracted and (2) form an extension of said boom by release of said first means and connection of said bifurcated portion to said outer boom member with said coupling means to accommodate pivotal movement of said jib assembly on said outer boom member; a mast pivotally supported on said outer boom member and having a stored position in juxtaposed relation to said outer boom member and an operative position extending above said outer boom member; cable guide means on the free end of said outer end section; cable means guided around said cable guide means and connected to said mast to maintain said jib assembly in an operative position when said jib assembly forms an extension of said boom, said cable means including a first cable having an intermediate portion cooperating with said cable means and a plurality of additional cables selectively attachable to opposite ends of said first cable so that the effective length of said cable means may be altered to position said jib assembly at any of a plurality of angular positions relative to said boom for each of said extended positions.

2. An extensible boom structure as defined in claim 1, further including manually operable winch means supported on said main boom member and having a winch cable extending therefrom; and guide means on said main boom member adjacent the opposite end of said base section for guiding said cable, said cable having clamp means on a free end thereof for releasable connection to said jib assembly so that actuation of said winch means accommodates pivotal movement of said jib assembly from the stored position.

3. An extensible boom structure as defined in claim 1, further including ground engaging means on the free end of said outer end section for engaging the ground during pivotal movement of said jib assembly to the operative position.

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