FIELD OF INVENTION
This invention relates to an improved boom assembly used in a crane to lift and reciprocate to and fro the lifted load. This invention comprises auto adjustment hook block, special jib head profile, anti two block wireless system, spread out lift cylinders and multiple fall hook block
BACKGROUND OF INVENTION
Boom is an important part of a crane, which is used to lift load from one location and place it at another. Normally, these booms have one or more members which move in an out through hydraulic cylinders. At the boom end side one block with hook is available which is mounted through rope laid on a winch. This unwinds or winds the rope when the members are moved out or moved in. Hence, when the operator actuates the members, it is required to loosen the rope so as to avoid any possibility of rope getting loaded. This may result in rope breakage or winch getting uprooted.
In a crane normally the jib head is provided [i.e. outer most portion of last sliding member] in such a way that, it is vertically bigger than in horizontal position resulting in hook block at lower height and wastage of actual working height utilization in a boom.
Rope is being laid horizontally/vertically in booms since 1960 onwards by many manufactures of Europe/USA/ Australia/ Asia. However, ease of operation, operation abuse and safety related issues are also required to be addressed, for which improved construction is required to be introduced.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide boom members actuation mechanism through ropes in a crane which has multiple extendable members.
Another object of the present invention is to provide to an improved boom assembly used in a crane to lift and reciprocate to and fro the lifted load in which crane operator operates the machine without making any operation error.
Further object of the present invention is to provide jib head with more narrow depth for full utilization of working height.
Yet another object of the present invention is to provide T' type boom section in such a way that ensures proper force transfer from one member to another.
Still another object of the present invention is to provide wider nylon pads ensuring bigger contact area and less pressure on pads.
Yet another object of the present invention is to provide an improved boom assembly used in a crane to lift and reciprocate to and fro the lifted load, which is efficient.
Yet another object of the present invention is to provide an improved boom assembly used in a crane to lift and reciprocate to and fro the lifted load, which is simple in construction.
STATEMENT OF INVENTION
According to this invention there is provided an improved boom assembly for a crane to lift and reciprocate to and fro the lifted load comprising of a jib head with a profile to keep snatch block straight, parallel ropes in hook block, T-boom sections, wider pads, rope anchoring arrangement and luff cylinder mounting brackets such as herein described.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:
Fig. 1 shows: auto adjustable hook block.
Fig. 2 shows: jib head profile.
Fig. 2' shows: known jib head and jib head of the present invention.
Fig. 3 shows: rope anchoring arrangement and luff cylinder mounting.
Fig. 3' shows: synchronous movement of all extensions.
Fig. 3A shows: extension and retraction rope anchoring on main boom.
Fig. 3B shows: rope laying inside the boom.
Fig. 3C: parallel rope laying of the present invention and cross rope laying of the prior art.
Fig. 4 shows: overlap of the extension and pad of the present invention.
Fig. 5 shows: anti two block wireless system.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:
The present invention discloses an improved boom assembly used in a crane to lift and reciprocate to and fro the lifted load.
Reference may be made to fig. 1, wherein winch rope holding the second boom member through pulleys and is connected to hook block, which is parallel to boom assembly. This configuration has the advantage that Hook block does not change its position until winch is operated.
Now, referring to fig. 2, in which the present invention is provided with a jib head with special profile, the rope laying and pulley arrangement on hook block. Ropes on hook block are parallel when viewed from front of the boom. Jib Head is such that Snatch Block always remains straight in any position of the boom as shown in fig .2'. This configuration has the following advantages:-
1. Hook block does not enter in jib head during full retraction.
2. Hook block due to special boom design and rope layout ensures that, it always moves parallel to ground at any angular position of boom.
3. Jib head profile ensures the highest pin height and maximum vertical clearance of hook block.
4. Special geometry ensures that, the no. of falls per pulley can be changed as per requirement.
5. Hook brackets are positioned in a way ensuring direct mounting of hooks rather using intermediate 'Dee' Shackle and additional link points.
6. Ropes are laid parallel on hook block when viewed from boom front ensuring hook block always moves straight even at no load.
The invention also comprising of rope anchoring arrangement and luff cylinder mounting brackets (as shown in fig. 3) with advantages as follows: -
1. Rope anchored close to mother boom bulk head resulting in safety to rope from damage.
2. Shorter rope length.
3. Boom luff cylinder mountings are spread out to achieve machine stability, lesser deflection and torsion.
Synchronous movement of all extensions (shown in fig. 3') wherein all sections move simultaneously and equally when actuated by hydraulic cylinder.
Extension & Retraction rope anchoring on Main Boom (Fig. 3A).
Ropes are anchored on TOP of the main boom in such a way that they are easy to assemble and provide strength to boom.
Rope laying inside the boom (Fig. 3B).
Extension and retraction ropes are laid on the side of 1st extendable member through pulleys which in turn are laid on front side pulleys in such a manner that when extension cylinder moves the 1st extendable member, the 2nd extension moves and the hook block is always maintained at its position as constant. Hence, it is not required to loose the winch rope so as to prevent the rope from getting damaged due to snatch block movement.
Referring to fig.3C. On Snatch block pulleys and ropes are laid parallel with the following advantages -
a. Snatch block always moves straight
b. Increase in capacity of snatch block.
c. More pulleys can be laid and hence accordingly the no of
falls and the total load lifted through snatch block can be
increased.
d. If 4 pulleys are laid then it is 4 fall otherwise conversion to 5
fall, 6 fall and so on is very easy.
e. Rope is always parallel which avoids chances of rope getting
damaged.
The invention is also provided with T boom sections and pads (fig. 4) having following advantages :-
1. Overlap of extension are so designed that, the loading on pads is optimum during full extension of boom and lifting maximum load as defined in load chart.

2. Extendable section of boom has special box geometry, offering higher modules and maximum strength.
3. Large seating space for resting pads (larger contact between moving sections) thus reduces play and torsional loads.
4. Extension and retraction ropes are clamped on boom top plate.
5. Single pin (in double shear) used on top pulley mounted on first extension, resulting easy assembly and disassembly and pin is simply supported between two plates implying to double shear.
6. Side pad locking arrangement is special having simple screw by who's tightening or untightening gap between two sections which can be increased or decreased.
There is a provision of safety switches like "limit switch" (fig. 5). An Anti-Two block system is fitted with wireless sensor for the prevention of damage to the boom tip of the boom of the crane by the travelling member. The two block system of the present invention includes an engaging mechanism movably mounted with the boom tip for engaging the traveling member when the traveling members moves into close proximity to the boom tip during lifting operations of the traveling member with the crane for the prevention of damage.
Thus, in the present invention additional extension and retraction ropes are mounted inside the boom which holds the extendable boom members and also adjusts themselves in such a manner that, when the members are moving out or moving in, it ensures the rope length does not change and hence hook block remains stationary at its position.
The boom assembly is having the following advantages :-
1. Auto adjusted hook block.
2. Multiple (one, two or three) extendable boom designs.
3. Maximum pin height due to special profile jib head.
4. Safety system having no electrical wire or rope to give audiovisual alarm in case of butting hook block with jib head. Machine cutoff feature is also available.
5. To ensure crane operator operates the machine without making any operation error.
It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

WE CLAIM:
1. An improved boom assembly for a crane to lift and reciprocate to and fro the lifted load comprising of a jib head with a profile to keep snatch block straight, parallel ropes in hook block, T-boom sections, wider pads, rope anchoring arrangement and luff cylinder mounting brackets such as herein described.
2. An improved boom assembly as claimed in claim 1, wherein anti-two block system is fitted with wireless sensor for the prevention of damage to the boom tip of the crane by the travelling member.
3. An improved boom assembly as claimed in claim 1 or 2, comprising of auto adjustable hook block and plurality of extendable booms with maximum pin height.
4. An improved boom assembly as claimed in any of the preceding claims, wherein all sections move simultaneously and equally upon being actuated by hydraulic cylinder.
5. An improved boom assembly as claimed in any of the preceding claims, wherein ropes are anchored on top of the main boom in such a way that, they are easy to assemble and provide strength to boom.
6. An improved boom assembly as claimed in any of the preceding claims, wherein extension and retraction ropes are laid on the side of first extendable member through pulleys which in turn are laid on front side pulleys in such a manner that when extension cylinder moves the first extendable member, the 2nd extension moves and the hook block is always maintained at its position as constant.
7. An improved boom assembly as claimed in any of the preceding claims, wherein the pulleys and ropes are laid parallel on snatch block.
8. An improved boom assembly as claimed in any of the preceding claims, wherein the winch rope holds the boom member through pulleys and is connected to hook block, which is parallel to boom assembly, due to which the hook block does not change its position until winch is operated.
9. An improved boom assembly for a crane to lift and reciprocate to and fro the lifted load substantially as herein described with reference to the accompanying drawings.