FIELD OF INVENTION
This invention relates to a novel boom assembly used in crane.
BACKGROUND OF INVENTION
In a pick-n-carry crane, boom is an important part which is used to lift load from one position and place it to another position. Normally, these booms have one or two members which move in and out through hydraulic cylinders providing motion to each individually. However, this configuration is associated with the following disadvantages :-
1. Each member moves independently.
2. The member which moves first is also not known as the one having less frictional resistance moves first. To overcome this problem, sequence valve is required to be installed.
3. For every member, cylinder is required making the assembly bulky. Further, more hydraulic hoses and pipes are required. Due to size and space constraint, it is not possible to accommodate more than two cylinders.
4. To provide sufficient overlaps among extendable members, longer boom is used and hence more travel length of the crane.
5. Another possibility is to use rope and pulleys inside the boom section. However, they are susceptible to rope coming out of pulley or pulley rubbing with the extendable members.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide a novel boom assembly used in crane which overcomes aforesaid disadvantages.
Another object of the present invention is to provide a novel boom assembly used in crane which is cleaner and compact.
Further object of the present invention is to provide a novel boom assembly used in crane which is efficient and reliable.
Yet another object of the present invention is to provide a novel boom assembly used in crane wherein the jib head is narrower in depth to make full utilization of working height.
Yet another further object of the present invention is to provide a novel boom assembly which is simple in construction as compared to conventional boom assembly.
STATEMENT OF INVENTION
According to this invention, there is provided a novel boom assembly used in crane comprising of a main boom housing a plurality of extendable members and hydraulic cylinder connected to each other and working in a combination such as herein described.
SUMMARY OF THE INVENTION
Said boom assembly having at least one extendable boom section. The boom members move synchronously together by means of hydraulic cylinders and ropes actuated by means of lever provided in the operator cabin.
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 of exemplary emb6diment of the present invention and wherein:
Fig. 1 shows : Boom assembly.
Fig. 2 shows: Jib head profile.
Fig. 3 shows: Rope anchoring arrangement and luff cylinder mounting
Fig. 4 shows: Inside construction of Boom and Pads arrangement
Fig. 5 shows: Auto adjusted Hook Block
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:
This invention discloses a boom assembly used in a crane comprising of at least one extendable boom section. Said boom section comprising of trunion type extension cylinder inside the second extension and hence boom length can be reduced to minimum value. The first extension is connected to this extension cylinder, which makes it move while actuating the cylinder. Second extension is connected through rope and pulleys to first extension which makes it move in or out depending upon cylinder movement.
Now, reference may be made to fig. 1, wherein a main boom is provided housing a plurality of extendable members, for ex: first extension (2), second extension (3) and hydraulic cylinder commonly known as extension cylinder (4).
The first extension is connected to main boom (1) through hydraulic cylinder. Another end of Extension cylinder is fixed to main boom which is not movable. Since cylinder is the most inner member, hence all hydraulic metal pipes are attached to cylinder and have openings at boom pivot point.
Now, to extend the first extension it is connected to extension cylinder through trunion at the rear end of the extension cylinder. Hence, actuation of the cylinder causes movement of said first extension and as a result boom members move out or move in.
The extension cylinder has atleast two pulleys in front through which the rope passes, one end of which is anchored to Second extension Rear and another end is anchored to the Main Boom, which either moves the second extension out or in depending upon the extension cylinder movement. Hence, all sections move synchronously and also equal length while actuating the extension cylinder.
Reference may be made to fig. 2 indicating jib head with special profile, rope aying, pulley arrangement on hook block and ropes on hook block, wherein the ropes are parallel when viewed from front of the boom. This configuration is associated with the following advantages-
1. Hook block does not enter jib head during full retraction.
2. Hook block due to special boom design and rope layout ensure its movement always 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 pulleys can be changed as per requirement.
ADVANTAGEOUS FEATURES
1. Multiple (two or three) extendable booms.
2. Simultaneous and equal movement of each extendable section.
3. All sections move with the single lever, which actuates the hydraulic cylinder and hence no manual intervention making it more user friendly and accident free with ease of operation.
4. Less travel order length of the boom as compared to conventional design and more overlap between extendable members imparting more strength to sections.
5. Less no of loose parts, pulley and ropes inside the boom leading to very less chances of failure.
6. Special profile jib head resulting in maximum pin height.
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. A novel boom assembly used in crane comprising of a main boom housing a plurality of extendable members and hydraulic cylinder connected to each other and working in a combination such as herein described.
2. A novel boom assembly as claimed in claim 1, wherein the first extendable member i.e. first extension is connected to the rear end of hydraulic cylinder known as extension cylinder.
3. A novel boom assembly as claimed in claim 1 or 2, wherein the extension cylinder is accommodated inside the second extendable member i.e. second extension and hence boom length can be reduced to minimum.
4. A novel boom assembly as claimed in any of the preceding claims, wherein the second extension is connected to first extension through rope and pulleys, which makes it move in or out depending upon cylinder movement.
5. A novel boom assembly as claimed in any of the preceding claims, wherein the first extension is connected to said main boom through the hydraulic cylinder, other end of which is fixed to main boom.
6. A novel boom assembly as claimed in any of the preceding claims, wherein the extension cylinder has a plurality of pulleys in front through which the rope passes, one end of which is anchored to Second Extension Rear and another end is anchored to the Main Boom, which either moves the second extension out or in depending upon the extension cylinder movement.
7. A novel boom assembly as claimed in any of the preceding claims, wherein the jib head is narrower in depth to make full utilization of working height, which is associated with the advantages such as herein described.
8. A novel boom assembly as claimed in any of the preceding claims, wherein the boom assembly is having several advantageous features such as herein described.
9. A novel boom assembly used in crane substantially as herein described with reference to the accompanying drawings.