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7 Nov. 19, 1946.
Filed Aug‘. 25, 1944
2 Sheets-Sheet l
£32 MW?“
NOV. 19, 1946.
Filed Aug. 25, 1944
2 Sheets-Sheet 2
Pei‘e21 406 68/7.
Patented Nov. 19, 1946
Ernest W. Taylor and Peter Nielsen, Bay City,
Mich, assignors to Industrial Brownhoist Cor
poration, Bay City, Mich.
Application August 25, 1944., Serial No. 551,174
(01. 212-59)
3 Claims.
, This invention relates to foldable A-frames
for excavating machines or other machines
equipped with booms.
,Excavating machines; and particularly cranes
of the shovel, clamshell, and dragline type are
readily mobile, so that they can be moved from
ing machine, the solid lines showing the A
frame raised, the broken lines showing the upper
section in folded position;
Fig. 2 is an enlarged side, elevational View of
the A-frarne, the broken lines illustrating the
upper section in folded position;
one job to another; and there is used as a part
Fig. 3 is a rear, elevational view;
of the. structure, a so-oalled A-frame, certain
Fig. 4 is a fragmentary, side, elevational view
portions of which project above the machine
illustrating the cable protecting means;
structure over which certain of the operating 10
Fig. 5 is also an enlarged, fragmentary, side,
cables of the machine are trailed and by means
elevational view showing the upper end of the
of which the elevation of the boom and operation
foldable section;
of other parts of the machine is accomplished.
Fig. 6 is a top plan view thereof; and
In the transportation of machines of this char
Fig. 7 is a fragmentary, side, elevational view
acter from one location to another, it is necessary 15 illustrating the detachable securing means.
that they pass under overhead structures such
Referring now to the drawings, the numeral
as highway bridges, grade crossings, wires, and
‘the like; and in certain instances the overhead
clearances on the job itself are limited.
It is
it indicates the base of a crane which is carried
by suitable crawlers or traction devices I l, the
base having mounted thereon a suitable platform
therefore desirable that the A-frame structure 20 ii on which the mechanical equipment of the
be designed so as to be as low as possible in order
excavation mechanism (not shown) is mounted,
that the machine may pass underneath low
this machinery being housed in a, cab structure
bridges, over-passes, or other obstructions. How
l3 as usual.
ever, an Aeframe that is low enough for such
A boom 14 is pivotally mounted for swinging
overhead clearances runs up the compressive 25 movement about the pivot point l5, and sheaves
loading of the boom very materially, increasing
l6 are journaled on a pin I‘! provided on the
its weight and decreasing the live load handling
outer end of the boom. A hoist ‘drum I8 is
capacity of the crane. An appreciably higher A
mounted on the platform 12 of the crane, and a
frame reduces the loading on the boom, allowing
hoist rope l9 is wound thereon, thence leading
a reduction in the weight, thus increasing the
over the sheave l5, and thence to a, fall block 255
available lifting capacity of the crane for live
as usual so that any desired hoisting operation
loads. Therefore, it is a prime object of the in
can be accomplished.
vention to provide an A-frame construction
An A-‘frame Wis mounted on the platform 12
which can be adjusted to a 'low height when
and is made up of compression struts or bars 22,
overhead conditions require that, and to a higher t the lower ends of said struts being connected
‘clearance for handling maximum loads when
to the crane platform ‘at 23, the ‘upper ends ‘being
overhead conditions permit.
formed with suitable openings ‘(not shown) to
. Another object is to provide a foldable A
accommodate a horizontally disposed shaft 24, 1
frame, the upper section of which is readily fold
and while ‘the A-‘fram’e comprises ‘two sides which
able upon the roof of the crane cab structure, 40 are identically similar, we shall, for the purpose
and which can be quickly and easily raised, by
of this description, describe but one side only.
power, and without strain or snapping of the
Stays 525 are “connected to the platform 12 at the
various cables, etc., when‘the machine is spotted
point 216 with the upper ends connected to the
and ready for operation.
shaft 24, and a cable protecting member 21 ‘is
A further object is to design an A-frame of 45 mounted on said shaft, the face of said mem
simple, practical, and substantial construction,
ber being crowned as shown and for a purpose
which can be easily manufactured and assembled,
to be hereinafter described. and which can be easily raised or folded, and in
Compression bars 28 form a part of the upper
a minimum length of time.
foldable portion of the A-frame and are con
In order to provide a more precise understand 50 nected to the shaft 24, the upper end being bi
ing of the nature and objects of the invention,
furcated as at 29 and a horizontally disposed
one speci?c embodiment will be described in con
nection with the accompanying drawings in
Fig. 1 is a side elevational View of an excavat
shaft 30 is mounted on the upper end as usual.
Tension members 3| are connected to the plat
form I2 at the point 32, the upper ends being
55 connected by a shaft 33 to which the lower ends
to a sheave cage 43 in which the sheaves 44 are
sion members respectively, the links being pivot
ally connected at their inner end portions, with
-The herein described construction and ar
of the links 34, which form a part of the upper
rangement admits of considerable modi?cation
foldable part of the A-frame, are also connected,
without departing from the invention; we
the upper ends of the links 34 being connected
therefore do not wish to be limited to the pre
to the horizontally disposed shaft 35, and links
v cise arrangement shown and described, which is
36 are also connected to the shaft 35 at a point
for the purpose of illustration only, as the scope
intermediate their length, the lower ends being
of protection is to be taken solely from the ap
bifurcated as at 3],‘ and openings 38 are pro
pended claims, interpreted as broadly as is con
vided in the lower end of the links 36 in register
sistant with the prior art.
with a similar opening 39 provided in the links
What we claim is:
34, bolts 40 serving to rigidly secure the said links 10
1. In a crane of the class described, in com
34 and 36 together as a-rigid structure when the
bination, a crane body, a boom pivoted thereto
A-frame is in raised position.
for raising and lowering movement, hoist means
The shaft 30 together with the links 28, 34 and
for raising and lowering said boom, an A-frame
36 complete the foldable upper section of the
15 structure mounted on the body and cooperating
with said hoist means and comprising a station- 7
Attached to the shaft 36 are the links 40a, to
ary, low arch section and an upper high arch
which the back stay 4| is connected, sheaves 42
section, tension members on the body, links pivot
being journaled on said links and form a part
ally connecting said upper section and the ten
of the assembly. The back stay 4| is connected
mounted, similar sheaves 45 being mounted in
one end of one link overlapping the other, quickly
the sheave cage 46 and the boom hoist line 41 is
removable means for securing the free overlap
trained over the various sheaves 44 and 45,
ping end of the one link to the companion link
thence being wound on the hoist drum 48 as
usual. A boom line 43 is connected to the cage 25 to provide a rigid structure, said means permit
ting folding of the high arch section when re
46 with the opposite end anchored to the outer
moved, and manually operable means connected
end of the boom, and it will be obvious that rota
to said links and to the crane body to prevent a
tion of the winding drum 48 will raise or lower
snapping action when the high arch section is
the boom accordingly.
When it is desired to collapse the A-frame for
2. A machine as de?ned in claim 1 in which
travel from one location to another, the end of
a crown-shaped cable protecting member spans
the upper end of the low arch section of the A
the boom is ?rst lowered to the ground or onto
a support (not shown), to slack the boom hoist
line 41, the bolts 40 are then removed, permitting
' 3. In a crane of the class described, in com
the links 34 and 36 to jackknife‘on the shaft 35
and the links 28, 34, and 36 to swing on the shafts
24,30 and 33, so that the parts assume position
bination, a crane body, a'boom movably mounted
thereon,‘ an A-frame mounted on the body and
comprising upper and lower sections,‘ tension
as clearly indicated in broken lines of Figs. 1 and
members on the body, the upper A-frame sec
2 of the drawings, the back stay cable 4| resting
on the crowned face of the member‘Z'l, and the 40 tion being pivotally mounted on the lower sec
tion, hoisting instrumentalities on the crane for
top of the A-frame will then be substantially
raising and/or lowering the boom, and including ‘
flush with the top of the cab structure l3 and
a back stay, means permitting the upper section
will readily clear all highway bridges, overpasses,
of the A-frame to swing to folded position, said
and similar obstacles, a block and tackle assem
means including pivotally connected foldable
'bly 5|! being connected to the shaft 35 and to
links connecting the upper section and the ten
lugs 5| provided on the rear end of the cab, and
sion members respectively, one end of one link
a handle 52 being provided for tightening or loos
being bifurcated to accommodate the end .sec
ening as desired, this block and tackle arrange
tion of the companion link, quickly removable
ment being of conventional design at present on
means spaced a predetermined distance from the
the market.
pivotal connection of the‘ linksfor locking them
When the A-frame is folded as indicated in
against pivotal movement and‘ form a rigid struc
broken lines in Figs. 1 and 2, and it’ is desired
ture, a crowned member on the lower section of‘
to raise it preparatory to hoisting operations, the
the A-frame and over which the back stay leads
operator actuates the boom hoist drum '48 in the
when the upper section 'is in folded position, and
usual manner, thus winding in the cable 41, and
an adjustable block and tackle means connected
placing strain on the hoisting cable which ?rst
to the links of the upper section of the A-frame
swings the link members 28, 34 and 36 upwardly,
and to the crane body to prevent snapping of
7. automatically swinging them to position indi
the A’-frarne members‘when said frame is swung
cated in solid lines, the bolts 4|] are then inserted;
the block and tackle assembly 5|) is removed, and
the machine is now ready for work, the raising,
is 'quick, easy and. smooth, there is no jerking or
undue strains, and no rearrangement of heavy
assembly is required by the operator. >
to raised position.
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