A crane gantry assembly includes a gantry pivotally connected to a crane bed, a backhitch pivotally connected to the gantry and detachably connected to the crane bed, and a control link pivotally connected to the backhitch and to the crane bed. The control link is used when maneuvering the backhitch between raised and retracted positions, such as when the crane is set up or taken down for transport.

BACKGROUND OF THE INVENTION 
This invention relates generally to the field of load-lifting cranes, and 
more particularly to a backhitch for such cranes. 
The increased load-lifting capacities required of modern cranes have 
resulted in a large increase in crane size. Usually, this necessitates 
cranes being disassembled into smaller components for transport to 
jobsites. Crane disassembly and re-assembly is a difficult task due to the 
long crane booms and complex rigging systems typically encountered. The 
crane components, (i.e. the boom, gantry, backhitch, rigging, etc.), must 
be assembled and aligned correctly for the crane to operate safely and 
effectively. 
A number of backhitches have been designed to help facilitate and simplify 
the task of assembling and disassembling cranes. Two of those designs are 
discussed in the following paragraphs. 
Folding link backhitch designs are characterized by the backhitch having a 
folding portion therein. The folding portion of the backhitch rotates and 
folds to allow the gantry assembly to be lowered. The gantry assembly of 
this design, however, is unstable during initial lowering. 
Telescopic backhitch designs are also known in the crane art. Often, the 
backhitch of these designs are formed of three separate links. The lower 
links, i.e. those closest to the crane bed, vertically telescope within a 
tubular structure on the crane bed or within themselves by means of, 
usually, a hydraulic cylinder. This telescopic movement causes the upper 
links of the backhitch and gantry to raise. This design is expensive, due 
to the numerous telescoping links and the hydraulic cylinders required, 
and is sometimes unstable due to the difficulty of balancing the hydraulic 
fluid flow to the cylinders on each backhitch leg. 
SUMMARY OF THE INVENTION 
A crane gantry assembly is provided including a gantry having a first end 
and a second end, the first end of the gantry pivotally connected to a 
crane bed; a backhitch having an upper end and a lower end, the upper end 
of the backhitch pivotally connected to the second end of the gantry, the 
lower end of the backhitch detachably connected to the crane bed; and a 
control link having a top end and a bottom end, the top end of the control 
link pivotally connected to the backhitch, the bottom end of the control 
link pivotally connected to the crane bed, the control link being 
operative to maneuver the backhitch between raised and retracted positions 
when the lower end of the backhitch is disconnected from the crane bed. 
The present invention allows the gantry assembly to be maneuvered between 
operational and stored positions in a smooth and stable fashion. The 
control link accurately guides the backhitch to the position where the 
backhitch is connected to the crane bed. 
The invention itself, together with further advantages, will be best 
understood by reference to the following detailed description taken in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
As an initial matter, it should be noted that cranes typically include a 
gantry with two legs positioned adjacent one another on a crane bed. The 
gantry is supported by a backhitch having two vertical legs spaced 
approximately equal to the spacing of the gantry legs. In the side views 
of the crane described below, only one leg of each of the gantry and 
backhitch is shown. 
Turning now to the drawings, there is shown in FIG. 1 a crane 10 including 
a boom 14, a crane bed 18, and a gantry assembly 22 incorporating the 
presently preferred embodiment of the invention. The gantry assembly 22, 
via rigging system 26, supports the boom 14 and, thus, the load 30 being 
lifted by the crane 10. The rigging system 26 is linked to a third drum 
(not shown) positioned on the crane bed 18. 
As best shown in FIGS. 1 and 2, the gantry assembly 22 includes a backhitch 
34, a mast or gantry 38, and a control link 42. A second control link (not 
shown) operates on the opposite side of the gantry assembly 22. The gantry 
38 has a first end 46 pivotally connected to the crane bed 18. The 
backhitch 34 has an upper end 50 pivotally connected to a second end 54 of 
the gantry 38 and a lower end 58 detachably connected to the crane bed 18. 
Finally, the control link 42 has a top end 62 pivotally connected to the 
backhitch 34 and a bottom end 66 pivotally connected to the crane bed 18, 
as shown in FIG. 4. 
The lower end 58 of the backhitch 34 is detachably connected to the crane 
bed 18 by any suitable means. However, a removable pin 68 is preferred. 
The remaining pivotal connections discussed above may be of any design 
suitable to the application. 
The backhitch 34 and the gantry 38 of the gantry assembly 22 may be of any 
suitable material and design, including a telescoping design. Preferably, 
however, the backhitch 34 and the gantry 38 are unitary structural 
members. 
When the crane 10 is taken down for transport to another jobsite, the 
gantry assembly 22 is first retracted to a position as shown in FIG. 2 and 
then unrigged from the boom 14. In this position, the gantry 38 rests atop 
the backhitch 34 and the backhitch 34 is supported by the crane bed 18. 
To retract the gantry assembly 22, the lower end 58 of the backhitch 34 is 
disconnected from the crane bed 18. In the preferred embodiment, this is 
done by removing the removable, connecting pin 68, as best shown in FIG. 
5. The pin 68 may be inserted and removed by any suitable means. 
Preferably, however, the pin 68 is actuated by an air cylinder (not shown) 
mounted on the crane bed 18. It must be emphasized that only the backhitch 
34 is disconnected during the retraction, and subsequent raising, of the 
gantry assembly 22. The connections between the backhitch 34 and the 
gantry 38, and the gantry 38 and the crane bed 18, remain secure. 
After the backhitch 34 and the crane bed 18 are disengaged, the weight of 
the gantry assembly 22 causes the control link 42 to rotate in a clockwise 
direction. The eccentric placement of the connection points between the 
control link 42 and the backhitch 34 and the crane bed 18 assures a smooth 
movement of the backhitch 34 from an upright position to a stored 
position. This movement prompts the lower end 58 of the backhitch 34 to 
swing to the right, as shown in FIG. 2, and results in the backhitch 34 
and the gantry 38 being lowered. The rotational movement of the control 
link 42 ceases when the retracted position is attained. In moving the 
gantry assembly 22 from a raised position to a retracted position, the 
control link 42 rotates through an angle of no more than about 90 degrees. 
Once the crane 10 has been transported to a jobsite, the gantry assembly 22 
is raised. This operation moves the control link 42 in a counter-clockwise 
direction. This rotational movement causes the lower end 58 of the 
backhitch 34 to move to the left and results in the backhitch 34 being 
raised. The control link 42 guides the lower end 58 of the backhitch 34 to 
the connection point 70 where the backhitch 34 is connected to the crane 
bed 18. 
Furthermore, as best shown in FIGS. 3 and 4, the control link 42 may 
further include a stop 72 for preventing the lower end 58 of the backhitch 
34 from being raised past the connection point 70. The lower end 58 of the 
backhitch 34 contacts the stop 72 when the backhitch 34 reaches the 
connection point 70. The stop 72 may comprise any means suitable for the 
application. In the preferred embodiment, however, the stop 72 includes an 
adjustable bolt assembly 74 located between the crane bed 18 and the lower 
end 58 of the backhitch 34. The adjustable bolt assembly 74 comprises a 
lock nut 78 turned on a bolt 82. The bolt 82 may be turned in or out and 
locked with the lock nut 78 to adjust the stop position, i.e. the position 
where the lower end 58 of the backhitch 34 contacts the stop 72. 
The present invention has the advantage of being able to maneuver the 
gantry assembly 22 between operational and stored positions in a smooth 
and stable manner. When stored, the gantry 38 rests atop the backhitch 34 
in a compact fashion. Furthermore, the control link 42 accurately guides 
the backhitch 34 to the position where the backhitch 34 is connected to 
the crane bed 18. 
It should be appreciated that the backhitch of this invention may be 
configured as appropriate for the application. The embodiment described 
above is to be considered in all respects as illustrative and not 
restrictive. The scope of the invention is indicated by the following 
claims rather than by the foregoing description. All changes which come 
within the meaning and range of equivalency of the claims are to be 
embraced within their scope.