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Патент USA US3034630

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May 15, 1962
3,034,620
w. c. HOLMES
SAFETY DEVICE FOR CRANE BOOM CONTROL
Filed Jan. 30, 1957
2 She-ets-Sheet 1
INVENTOR.
mum/w c. HOLMES
BY
X4444 W
May 15, 1962
w. c. HOLMES
3,034,620
SAFETY DEVICE FOR CRANE BOOM CONTROL
Filed Jan. 50, 1957
2 Sheets-Sheet 2
lww:
INVEN TOR.
40/‘ 4 MM c. 1/0‘ M65
4 1 7024/5)’
Free
3,h3i,b2h
Patented May 15, 1962
2
.
3,034 626]?
SAFETY lDlE‘VlQE Flllt (JEEANE BUUM CQN’PCRQL
William C. Holmes, 4520 W. .lle?erson, lEcorse, Mich.
Filed .lan. 30, 1957, Ser. No. 637,297
4- Claims. (Cl. 192-41)
A boom in a power crane of conventional construction
is pivotally mounted at its lower end upon the turntable
of the crane and is adapted to be lowered or raised by
means of a cable which is wound upon a cable drum. The
controls the movement of the boom is attached to the
upper end thereof, passes over a pulley 18 at the upper
end of a stationary beam 19 which is mounted upon a
turntable 17 of ‘the crane, and is wound upon a drum 20
which is also mounted on said turntable.
Co-axially mounted with the drum on a shaft 21 is a
gear wheel 22. The gear wheel is in mesh with an idler
23, and by means of said idler is in engagement with a
pinion '77 mounted upon brake wheel 24 journaled on a
shaft S known as a swing shaft.
Mounted upon said shaft S is a brake wheel 24, and
encircling said wheel is a brake band 25 which at one
rotation of the drum is controlled by a brake which may
be operated by suitable means responsive to manual opera
tion thereof.
end is anchored to a stationary member 26 rising from
The boom may be lowered under its own weight or the
the surface of the turntable. At the opposite end the
15
combined weight of the boom itself and a load supported
brake band 25 is connected to a horizontal rod 28. A
thereby, and the lowering itself may be controlled by
spring 29, coiled about the rod, bears at one end against
means of a brake, which in the older models of cranes is
a stationary member 30‘ and keeps the band in a tight
done manually. At times, however, it appears desirable
frictional engagement with the
portion of said brake
to retard or regulate the lowering of the boom by means
wheel M. A ratchet wheel 31, secured to brake wheel
controlled by the engine of the crane.
24 is loosely mounted upon the same shaft which carries
This is desirable when the load is of relatively large
the brake wheel, is controlled by a pawl 32. Midway
weight or where special care has to be taken in lowering
its length pawl is vfulcrumed upon ‘a pin 27 and is pro
of the load because of its nature or the site upon which
vided, at the end remote from said ratchet wheel, with
the load is to be placed. In such cases it is possible to
a weight 33, and the object of the weight being to keep
have the cable drum coupled to the ‘engine by a clutch 25 the pawl normally in engagement with the teeth of said
which has to be operated manually.
ratchet wheel to prevent rotation thereof.
However, there is always the danger that by oversight
As at times it is desirable to have the lowering of the
the operator of the crane might fail to employ the clutch
boom controlled by the engine of the crane, a special
when most needed for connecting the cable drum to the
mechanism is used for that purpose. It includes a sprocket
engine driven hoist shaft, so that as a result thereof the
wheel 34 loosely journaled and mounted upon one end
boom may drop down with excessive speed, damaging the
of a hoist shaft H which, through intermediate means,
load or imperiling workers in proximity of the boom. It
is driven by the engine of the crane. Connected to said
was to prevent such an eventuality that I have devised
wheel by means of a driving chain 35 is another sprocket
pneumatic means which, on release of the brake, will
wheel 36 which is mounted upon shaft 37. A gear wheel
automatically couple the engine of the crane to the cable
38, mounted on the same shaft, is in mesh with gear
drum.
wheel 22 controlling the cable drum.
A further object of the invention is to provide means
A clutch 39, a long lever 46 is slidably keyed to hoist
which may be easily installed on the cranes already oper
shaft H and is connected to said clutch, serves as a
ated by pneumatic means without the need of any struc
means of coupling the hoist shaft driven by the engine to
tural changes in said crane.
the sprocket wheel 34 in turn connected by chain 35,
I shall now describe my improvement with reference
sprocket ‘gear 36, and gear wheel 38 to ‘gear wheel 22.
to the accompanying ‘drawings in which:
FIG. 1 is a diagrammatic presentation of a power crane
of the type in which my device may be installed;
‘FIG. 2 is a side elevational view of the mechanism con
trolling the operation of the boom of the crane, the View
including my device;
FIG. 3 is a perspective View of a stand, shown in
fragment, and a lever mounted thereon and serving for
the operation of the boom;
FIG. 4 is a diagram indicating the path of the move
ment of the lever in ‘the course of its operational use;
The lever, which is disposed diametrically with respect to
the clutch 39, is hinged at one end at 78, to a stationary
45 member 4-1 on the stationary beam 19, while the oppo
site end of the lever terminates with a downwardly
turned handle 42. Coiled spring '71, FIG. 5, is anchored
at 7d to stationary member 69 and at its opposite end is
joined to lever 40 normally biasing the clutch 39 into
50 a disengaged position with respect to the sprocket wheel
34. Thus power driven hoist shaft H is disconnected
from cable drum 29.
Located at the front end of the turntable is a stand
43, and mounted thereon is a lever 44 terminating at the
55 upper end with a ball 45, this being of a size to ?t into
for engagement of a clutch which forms a part/of my
the palm of the operator of the crane. Adjoining the
device.
‘
ball is a push button l‘it; in an electric circuit which in
Similar numerals refer to similar parts throughout the
cludes switch means within the stand and solenoid means
several views.
under the turntable.
The drawing in FIG. 1 shows the principal elements of
The drawing in FIG. 2 shows a single solenoid 47
a power crane of the type in which my improvement may 60 which controls a valve 48 upon a pipe 48a shown in
be used. The elements include a cab lit, a traction gear
fragment and leading from the source of supply of com
11 of the crawler type, a boom 12, and a bucket 13 which
pressed air, such as a compressor. Extending from the
is suspended from a cable and which may be lowered
valve is a pipe 49 which leads to a union 50, while an
or raised by means of said cable.
65 other short pipe 51 leads from the same union to a cyl
As my device is to be employed with certain elements
inder 52 from which air, under pressure, is adapted to
of the mechanism for raising and lowering of the boom,
actuate a rod 53.’ The rod extends slidingly from the
1 will ?rst describe such pertinent members of the mech
cylinder and is pivotally connected at its outer end to
anism as may be needed for the understanding of the
the lower end of a vertically-disposed lever 54. The
operation of my device.
70 lever, which is pivotally secured at its upper end to the
The boom is mounted pivotally ‘at its lower end by
stationary member 26, as shown at 55, bears at its mid
means of a pin 15 in a bracket 16. The cable 14 which
portion against a cap 56 which is secured to one end of
‘FIG. 5 is a top View of a horizontally-disposed cylinder
including a movable rod operated by pneumatic means
3,034,620
3
4
mally kept in 1a retracted position within said cylinder
by suitable spring means, but that it is adapted to be
coiled spring 71 will pull the lever 40 towards the cylinder
rod 73 is pushed out by air pressure, overcoming the
said rod 28 and which is connected to one end of the
tension of spring 71. The rod, extending outwardly from
brake band 25.
the cylinder 65, bears against the lever 40 and moves it
Another pipe, 64, leads from the union 50 to a cylin
outwardly from said cylinder, causing it to shift the
der 65 which is mounted on a bracket 66, the latter being
clutch 39 on the hoist shaft H from its disengaged to
secured to .a stationary brace 67 of the framework of
its engaged position relative to sprocket gear 34. This
the crane upon said turntable. The cylinder, best shown
serves to couple the power of the engine of the crane to
in FIG. 5, is kept in place by means of a band 68 which
the cable drum or boom drum 20. As ‘a result thereof,
is carried by the bracket, the latter being in a radial rela
the unwinding ‘of the cable is retarded and the speed of
tion to said cylinder. One end of the cylinder is pro
vided with a radially-extending bar 69, and connected 10 the unwinding may be controlled by the engine which is
capable of a wide range of variable speeds.
thereto, by means of an eyelet 70, is one end of a coiled
Upon return of the lever 44 to the neutral position in
spring 71, while its other end is hooked to the lever 40,
dicated by numeral 45a in FIG. 5 and on release of the
a shown ‘at 72.
switch button 46, the current which energizes the sole
The opposite end of the cylinder is provided with an
noid 47 will be cut off and the valve 48 which is controlled
axial opening through which a sliding rod 73 extends
by said solenoid will be closed. As a result thereof, the
outwardly. It will vbe understood that the rod 73 is nor
65, the rod 73 will be withdrawn into the cylinder under
the tension of a spring within said cylinder, and the clutch
39 will be shifted by said lever '46 back to its disengaged
pushed outwardly against said lever 40 by compressed
air admitted to the cylinder through said pipe 64.
position, uncoupling the engine from the boom hoist
The drawings also show a clutch 63 slid-ably keyed on
one end of the swing shaft S of the crane which is also
controlled by pneumatic means. These include a cylin
der 58 which is mounted in a housing ‘bracket 59. A red
drum.
The closing of the valve 48 will also cut off the supply
of air under pressure from the cylinder 52 and cylinder
extending from the cylinder and adapted to be actuated
75, causing the respective mechanisms operated by rods
by air pressure is connected to the lower end of a vertical
lever 60 which is fulcrumed at 61 and which terminates
at its upper end with a fork 62. It is this fork that is
adapted to shift the clutch 63 from its engaged to its dis~
engaged position with respect to brake wheel 24, or vice 30
extending from said drums or cylinders to return to
versa.
Air under pressure is applied to the cylinder through
their normal positions.
More speci?cally, rod 73 will be withdrawn into the
cylinder 65 by spring means located within said cylinder,
permitting the coil spring 71 to draw the lever 46 towards
said cylinder. As a result thereof, the lever 40 will shift
the clutch 39 on the hoist shaft from its engaged to its
a pipe 57 controlled by means of another solenoid valve
which is not shown. The solenoid valve operates only
disengaged position, thus disconnecting said shaft H which
shown in FIG. 2 between engaged ‘and disengaged posi
tion relative to sprocket wheel 34. A pipe 74, extending
laterally from said pipe 64, leads to a vertical cylinder
the air-controlled means pertaining to my device may
be varied in form and their locations with respect to
each other or the pertinent elements of the crane without
is driven by the engine of the crane from the cable
35 drum 20.
when the boom is to be raised.
_
As my device operates only at the time when the
As these details pertaining to the operation of the
boom is to be lowered, the description of the functions
clutch 63 are well known ‘and are no part of the appli
of the respective mechanisms operated by the last-named
cant’s invention, no further particulars on the subject are
cylinders for raising the boom does not appear necessary
deemed necessary herein.
in this disclosure.
It will be noted that, as before stated herein, said lever
It will be understood that the forms and locations of
40 serves as a means of moving the clutch member 39
thereby departing beyond the range of the invention dis
closed herein. It will be also understood that any other
a rod 76 adapted to be pushed upwardly by air pressure
?uid medium than compressed air may be used to actuate
against the lower end of weight 33 ‘at one end of the
my device and the elements working in combination
fulcrumed pawl 32.
therewith.
I shall now describe the working of my device in the
What I, therefore, wish to claim is as follows:
course of the operation of the boom.
50
1. In a crane, a power driven hoist shaft, a rotary
It will ‘be assumed that the boom is up land that the
cable drum, a brake to control the rotation of said drum,
clutch 39 due to spring 71 and lever 40 is in its normal
a normally disengaged clutch upon said hoist shaft and
disengaged position relative to sprocket wheel '34 on the
movable thereon from disengaged to engaged position to
end of the hoist shaft. Now, should the operator desire
to lower the boom, he can do so by means of the lever 55 couple the hoist shaft to the drum, a lever pivoted at one
75 on the upper surface of the turntable 17 and contains
44, which in a well-known crane now in use has to be
swung from its neutral position, indicated by numeral
45a in the diagram shown in FIG. 4, to the ‘left to the
position marked 45b. At the same time as the operator
will grasp the ball 45 at the upper end of the lever, he
will depress the switch button 46. The button and an
auxiliary switch not shown will close an electric circuit,
energizing the solenoid 47. The latter will open the
valve '48 admitting air under pressure to cylinder 52.
As a result thereof, the rod 53 will swing the lever 54
from its pivotal connection at 55 against the cap 56 on
the rod 28, and, overcoming the tension of the coiled
spring 29, will loosen the brake band 25 on the brake
wheel 24.
Simultaneously, air under pressure is admitted to the
cylinder 75 located under the weight 33 so‘ that the rod
76 will rise from the cylinder and lift said weight, thus
disengaging the pawl 32 from the teeth of the ratchet
wheel 31. Also simultaneously, air under pressure is de
livered through pipe 64 to the cylinder 65. Here the
end to a stationary support and intermediate its ends se
cured to said clutch, spring means secured to a stationary
support and joined to and acting upon the lever to hold
the clutch in its disengaged position, a cylinder upon a
60 stationary support including a reciprocal piston rod ex
tending axially into contact with the lever at substantially
right angles thereto, 1a pipe leading to the cylinder to
supply thereinto a ?uid medium under pressure to push
the rod outwardly against said lever, for moving said
65 lever and the connected clutch to engaged position, a
power means adapted to release the brake, a manual con
trol switch means, a valve connected to a source of ?uid
under pressure and having an outlet connected to said
pipe and to said power means, a control means for open
70 ing said valve connected to said manual control switch
so that on actuation of said switch said valve is opened
actuating said power means, releasing said brake and
simultaneously delivering ?uid to said cylinder to shift
said lever ‘and connected clutch to engaged position rela
75 tive to the cable drum.
5
3,034,620
2. In the crane of claim 1, said brake including a
power driven swing shaft, a brake drum loosely journaled
thereon, a gear train interconnecting said brake drum and
said cable drum, and a resiliently mounted brake band
normally engaging said brake drum retaining said cable
drum against rotation.
3. In the crane of claim 1, the connection between
said hoist shaft clutch when in engaged position relative
to said cable drum including a sprocket gear train con
6
semb'ly upon said swing shaft and movable thereon from
disengaged position to engaged position for transmitting
driving power from said swing shaft to said brake drum
and said gear means to said cable drum, ‘and means en
gageable with said swing shaft clutch for moving the
same from disengaged to engaged position.
References Cited in the ?le of this patent
UNITED STATES PATENTS
nected to said cable drum in driven relation, said latter 10
clutch when moved by said lever to engaged position,
1,979,780
being in operative engagement with said gear train.
2,098,342
4. In the crane of claim 1, said brake including a
2,445,116
power driven swing shaft, a brake drum loosely journaled
2,506,842
thereon, a gear train interconnecting said brake drum 15 2,590,172
and said cable drum, a normally disengaged clutch as
2,693,341
Turney ______________ __ Nov. 6, 1934
Knutzen _____________ __ Nov. 9, 1937
Huston ______________ __ July 13, 1948
Rockwell ____________ __ May 9, 1950
Guier et al ___________ __ Mar. 25, 1952
Fox _________________ __ Nov. 2, 1954
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