Note: Descriptions are shown in the official language in which they were submitted.
I
This invention relates generally to aerial
platforms and, more particularly, to such platforms which
may be attached to and used with hydraulic cranes.
The present invention provides an aerial platform
which is pivotal suspended from a bracket pinned to the
cross-shafts projecting beyond a side plate on the boom
tip of a hydraulic crane. The pivotal suspension permits
the platform to remain level as the crane boom is
elevated, while the pinned connection to the cross-shafts
allow the attachment to be readily removed and
reinstalled. The platform includes a basket and is
positioned adjacent to the boom tip so that tools or other
light materials Jay be exchanged between the ground and
the basket by means of the whip line on the crane. A dash
pot, preferably in the form of an automotive shock
absorber, attached between the bracket and the platform
controls the rate of movement and hence prevents any
sudden rotational movement of the platform relative to the
boom tip as the boom is elevated into a desired working
position. A hand operated brake is provided to prevent
rotation of the platform relative to the boom tip while
the platform is occupied and in a working position. A
means for storing the platform while attached to the boom
tip so that the crane remains operable for certain uses
and may also be transported in a normal manner is also
provide.
Other attributes and advantages of the present
invention will become more readily apparent from a perusal
of the following description and the accompanying drawings
wherein:
Figure 1 is a side elevation Al view of a
hydraulic crane with the present invention attached
thereto;
Figure 2 is a detailed view of the attachment
shown in Figure l;
Figure 3 is a view taken on line 3~3 of Figure 2
with portions broken away and eliminated; and
Figure 4 is an expanded view of a preferred
I'
--3--
embodiment for the brake mechanism utilized in the present
invention.
Referring to Figure 1, there is shown a hydraulic
crane, indicated generally at 10, having a multi-section,
extendible boom 12 pivotal mounted on the crane's upper
14. The upper is rotatable about a vertical axis on the
lower 16. As illustrated in Figure 1, the entire crane 10
is supported for stability on outrigger jacks 18, which
tray be retracted to permit the wheels 20 on the lower 16
to engage the ground for transport in a conventional
manner. Hydraulic cylinder means 22 is connected between
the boom 12 and the upper 14. With both the boom and the
cylinder means 22 fully retracted, the boom 12 is oriented
as indicated by solid lines and when both the boom and the
cylinder means are fully extended, the boom 12 is
configured as indicated by dotted lines in Figure 1.
An aerial platform 23 is pivotal suspended from
a boom tip 24 secured on the free end of the outer section
of the boom 12. An auxiliary hoist 26 mounted on the
upper 14 has a wire rope 28, commonly referred to as a
whip line, wound thereon and trained over a sheave 30, as
shown in Figure 2, rotatable carried on a cross-shaft
between the side plates, one of which is shown at 32, of
the boom tip 24 and an auxiliary sheave 34 on a shaft
cantilevered from the tip 24 by means of arm 36. A hook
38 is attached to the free end of the wire rope 28. Since
both the platform 23 and the auxiliary sheave 34 are
suspended from the boom tip 24, the hook 38 will, as it
approaches the boom tip as a result of the auxiliary hoist
reeling in the wire rope 28, be in close proximity to the
platform 23 to enable a worker oil the platform to remove
or attach material from or to the hook.
Referring now to Figures 2 and 3, a pair of
cross-shafts 40 and 42 project beyond the wide plates 32.
A bracket 44 has a pair of tubes 46 and 48 secured thereon
which tubes engage the ends of the cross-shafts 40 and 42
respectively. The tubes are cross-bored in alignment with
--4--
bores provided in end fittings on the cross-shafts, one of
which is shown at 50. A pair of pins, one of which is
shown at 52 inserter through the tube 48 and the fitting
50, releasable secure the bracket 44 to the boom tip 24.
The aerial platform 23 includes a basket 54, preferably
constructed ox an electrically non-conducting material,
such as f fiberglass, secured to a suspension link 56. The
link 56 is pivotal connected to the bracket 44 by means
of a pivot pin 58 attached to the link 56 and rotatable
retained within a bushing 60 provided in the bracket 44.
A dash pot, which may be an automotive shock
absorber 62, is pivotal attached at 64 to the bracket 44
and at 66 to an arm 68 secured to the link 56. Rotation
of the link 56 clockwise, is viewed in Figure 2, will
cause extension of the shock absorber 62, and rotation in
the opposite direction will cause retraction. The shock
absorber 62 will control the rate of such rotation, and
hence will preclude any sudden rotational movement to the
basket 54 while the boom is being elevated or lowered.
Thus, the basket 54 will retain virtually vertical when
moved to and from a working position. Movement of the
occupant and the shifting of his or her center of gravity
resulting therefrom will not cause an unsettling and
unexpected sudden rotation of the basket.
A brake, indicated generally at 70, is provided
to lock the link 56 relative to the bracket 44. When so
locked by engagement of the brake 70, an occupant of the
basket is provided with a stable platform from which work
may be performed on elevated structures or lines. The
brake 70 includes a rotor sector 72 secured to the bracket
44. Calipers 74 carried by a actuating member 76 secured
to the lynx I are capable of engaging the rotor sector 72
to lock the link 56 to the bracket 44. An actuating lever
78 rotatable mounted on the member 76 has a central
position, wherein the caliber 74 are out of engagement
with sector 72 permitting pivoting of the link 56 relative
to the bracket 44, and movement in either director from
I
--5--
its central position causes the caliber 74 to engage to
sector 72 thereby locking the link 56 to the bracket 44.
Movement of the actuating levers 78 is controlled by a one
way control device 80, such as that made by Quadrastat
Controls Corp. The control 80 has an input mean 82 and
output means 84. A hand lever 86 is affixed to the input
means 82 and the link 88 is pivotal connected between
the output means 84 and the actuating lever 78. The
control permits rotation of the output means 84 when a
force is applied to the lever 86, but precludes such
movement when forces are applied to the output means 84.
Consequently, the brake 70 can be released or engaged only
through manipulation of the lever 86, and unintentional
release or engagement as a result of vibration or other
forces applied to the output means 84 will be precluded.
the position of the hand lever 86 when the brake 70 is
released is shown by solid lines in Figure 2 and movement
of this lever to either of the dotted line positions will
cause the break to engage. Thus, should an occupant need
to quickly apply the brake 70 he or she would not have to
consider which direction to rotate the hand lever; the
brake 70 will be engaged with movement in either direction.
In order to store the basket I along side the
boom 12, a loop 90 is attached to the side of the basket
54 adjacent to the boom and along the basket's bottom
edge. A stabber member 92 is formed on a bracket I
attached to the boom 12. The stabber member 92 engages
the loop 90 when the basket is held parallel to the bottom
of the boom and the boom is then fully retracted. An
inclined surface 96 on the stabber member 92 cams the
basket 54 upward to facilitate full engagement of the loop
90 by the stabber member 92 should the basket 54 not be
perfectly parallel to the bottom of the boom 12. In order
to move and hold the basket in the proper position for
engagement of the stabber member 92 with the loop 90, a
rope I may be attached to a second loop 98 secured to the
basket 54 and passed through a third loop 100 attached to
~35i~
--6--
bracket 94. Tension force applied to the rope 95 permits
rotation of the basket 54 to its proper position for
engagement of the stabber 92 with the loop 90 from a
remote position. When the boom is then fully retracted,
the stabber 92 will engage the loop 90.
While a preferred embodiment of the present
invention has been described and illustrated, it is to be
understood that changes and modifications may be made
therein without departing from the spirit of the invention
is defined by the scope Or the appended claims.
What is claimed is:
