The present invention relates to an efficient boom for pick and carty hydraulic
mobile crane and more particularly an efficient Outer Main boom for pick and
cany type of hydraulic mobile cranes for Lifting loads.
BACKGROUND OF THE INVENTION:
In the known Art Pick and Carty types of mobile hydraulic cranes have a
telescopic boom assembly for lifting and handling the load.
The boom assembly comprises of an outer main boom attached to the crane at
rear end and at least one or more extension members which are disposed inside
the outer main boom from its front end. Hydraulic cylinder is connected
between outer main boom and first extension boom. Hydraulic cylinder
facilitates for telescopic driving in and out the first extension boom. In the
event of two or more extension booms from the outer main boom, a multiple of
hydraulic Ram means or a combination of hydraulic ram and synchronized
extension using Chains or Cables are operated over a set of pulley or rollers.
The Outer Main boom structure is fonned by welding steel plates cut to required
shape and size. The Main boom body has a hollow structure inside. The Boom
structure thus made can have additional plates welded to the side walls of outer
fixed boom for extra reinforcement required. These additional plates can be
called as "double" plates.
2
The Crane Outer Main boom has at its Rear bottom side has suitable shape and
provision for a pivot hole for connection with Crane chassis. While the front
bottom side of the Outer main boom has pivot plates for lifting ofload. Also the
fi'ont of Outer main boom has opening to the hollow inside to accommodate at
least one extensible boom.
Now on the Outer Main Boom; the Hook shackles are mounted for lifting the
loads. These hooks shackles have an assembly of hook, shackle, pin; safety
latch and is mounted the pivot plates fixed to the front bottom side of both outer
main boom and in some case on first extension boom also.
Some plior art cites the usage of the said hooks only at the base of an outer main
boom, while some other citations also have a slot in outer fixed boom base,
where hooks can also be mounted on to the first extension boom base. These
hooks on base of fii"st extension boom can travel along in the slot in base of
outer main boom.
A separate hook block is connected through winch driven wire rope to the boom
assembly of outer main boom and first extension boom. This hook block is
movable with a wire rope that connects hook block and winch and is also used
for lifting loads besides the fixed hooks secured at the base of boom members.
In the case of Outer main boom assembly without slot at the base of outer main
boom in a crane, the prior art consists of at· the least three or more individual
hook mounting pivots fixed at the base of the outer main boom. These pivots are
mounted at different locations depending upon the rated loads to be lifted by the
crane. As shown in Figure I describing PRIOR ART. These individual pivot
3
plates are generally fixed on short plates and then fixed to the outer main boom
front bottom end.
The drawback of such method is that the individual hook mounting pivots have
limited strength. In the crane work involving pulling dragging of load, these
individual pivot plates can break and separate from bottom of outer fixed boom.
Another disadvantage of individual hook mounting pivot plates is that welding
is used to fix hook mounting pivot plates to bottom of outer main boom. The
welding is done at locations where hook mounting pivot plates are placed at
bottom of outer main boom. This involves in many start and stops of welding
giving rise to weld stresses and weakening at point of each stmt and stop of
weld location.
OBJECTIVE OF THE PRESENT INVENTION:
Therefore in view of disadvantages cited above; one of the objectives of the
present invention is to integrate these separate hook mounting pivot plates into
single profile hook mounting pivot plates with various pivot holes for mounting
hooks.
Another object of this invention is that these single profile hook mounting plates
are placed at wide distance apart for an improved load bearing strength of the
fi-ont bottom m'ea of the outer main boom as shown in figure 2 and 3.
Yet another object of this invention is to mount these wider spaced single
profile pivot plates at front bottom side of outer main boom with an double plate
4
for better and increased load bearing strength. This double plate has slots at
suitable location as shown in figure 2 and 3. The double plate is fixed with base
of outer main boom by welding in slots and along sides.
Still other object of this invention these hook mounting single plate pivot plates
and double plate with slots is attached to the front bottom side of outer main
boom by means of welding.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
We shall now describe the invention with reference to accompanying
drawings which are given for the sake of illustration, but do not restrict the
scope of present invention.
Referring to drawings:-
Fig. I shows prior 311 Crane Outer Main Boom view Showing fixing of Hook
Mounting Pivot Plates at various locations.
Fig 2 shows Schematic Bottom view and Side view of Fixed Outer Boom
Showing fixing and position of Hook Mounting Pivot Plates.
Fig.3 shows Isometric Bottom view of Fixed Outer Boom showing fixing and
position of Hook Mounting Pivot Plates.
5
Fig.4 shows Isometric Bottom view of Fixed Outer Boom front bottom showing
mounting of hook anangement with pin and shackle inside the hook mounting
pivot plates.
BRIEF DESCRIPTION OF THE INVENTION
According to present invention there is provided a smooth jerk An efficient
boom for pick and cany hydraulic mobile crane comprises a boom assembly
for pick and cany type mobile hydraulic crane, single profile plates with pivot
holes fixed on a double plate mounted on front bottom of outer main boom of
crane for lifting the load, the said pivot plates placed at suitable distance so that
the hook shackles can be mounted inside with a pin and the said double plate
having slots symmetrical to the width of the plate so as to weld with bottom
plate of outer main boom.
The said single profile hook mounting pivot plates comprise of a set of various
pivot holes for mounting the hooks.
The said single profile hook mounting pivot plates being placed at wide distance
apati for an improved load bearing strength of the front bottom area of the outer
main boom.
The said wider spaced single profile pivot plates being mounted at front bottom
side of outer main boom with a double plate for better and increased load
bearing strength.
6
The said double plate comprising slots at suitable location fixed to the base of
outer main boom through welding in the slots and along sides.
Outer main Boom of crane is a welded long hollow box structure made up of
four individual side plates or a Bent U Steel channel and a closing plate to fonn
a box-shaped structure inside being hollow space. One front side of the structure
is kept open for extension booms to be put inside the hollow of outer fixed
boom and the rear side is closed for providing strength and a suitable provision
for fixing to the crane machine.
As shown in Figure 2 and 3; two single profile hook mounting pivot plates are
fixed on the fi'ont bottom side of Outer Main boom on a double plate. These
plates have at least three or more Pivot holes for mounting Hooks. These plates
are mounted at wider distance symmetrical to outer fixed boom bottom so that
the hooks with shackle can be mounted inside these one piece hook mounting
plates with a Pin as shown in Figure 4.
This wider and one piece hook pivot plate design provides for better and
increased load bearing area at the base of the outer fixed boom. The bottom
double plate has a particular shape and slot shape cutouts in the middle. These
cutouts are spaced sylmnetrically with each one piece hook mounting pivot
plates 1 & 2. The bottom double plate is fixed with Outer Main boom bottom
plate with welding on the sides and the middle slot cutouts.

I . An efficient boom for pick and carry hydraulic mobile crane comprises a
boom assembly for pick and cany type mobile hydraulic crane, single profile
plates with pivot holes fixed on a double plate mounted on front bottom of outer
main boom of crane for lifting the load, the said pivot plates placed at suitable
distance so that the hook shackles can be mounted inside with a pin and the said
double plate having slots symmetrical to the width of the plate so as to weld
with bottom plate of outer main boom.
2. An efficient boom for pick and carry hydraulic mobile crane as claimed
in claim I and said single profile hook mounting pivot plates comprise of a set
of various pivot holes for mounting the hooks.
3. An efficient boom for pick and cany hydraulic mobile crane as claimed
in claim I and said single profile hook mounting pivot plates being placed at
wide distance apatt for an improved load bearing strength of the front bottom
area of the outer main boom.
4. An efficient boom for pick and carry hydraulic mobile crane as claimed
in claim I and the said wider spaced single profile pivot plates being mounted at
front bottom side of outer main boom with a double plate for better and
increased load bearing strength.
8
5. An efficient boom for pick and cany hydraulic mobile crane as claimed
in claims I and 2 and the said double plate comprising slots at suitable location
fixed to the base of outer main boom through welding in the slots and along
sides.