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Патент USA US3053958

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sePt- 11, 1962
J. K. FIGENSHAU ETAL
3,053,948
COLLISION PREVENTER
Filed June 9, 1960
2 Sheets-Sheet 1
INVENTORS
JAMES K. FIGENSHAU
WILLIAM H. HAINER
AGENT
‘Sept. 11,1962
3,053,948
J. K. FIGENSHAU ETAL
COLLISION PREVENTER
Filed June 9, 1960
2 Sheets-Sheet 2
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INVENTORS
JAMES K. FIGENSHAU
WILLIAM H. HAINER
3,053,948
Patented Sept. 11, 1962
2
an improved collision detecting and preventing device
which will protect the device effectively from collisions
with foreign objects at any side of the device to be pro
tected.
These and other objects will be apparent from the
3,053,948
James K. Figenshau, Big Lake, and William H. Hainer,
COLLISION PREVENTER
St. Paul, Minn, assiguors to General Mills, Inc, a
corporation of Delaware
Filed .l'nne 9, 1960, Ser. No. 35,026
11 tijlaims. (Cl. Mill-451.42)
accompanying description.
Brie?y stated, the present invention includes a device
for mechanically detecting and preventing an impend
This invention relates to collision preventers and more
ing collision between a physical obstruction and a device
particularly to collision preventers for protecting mov
able devices from cOlliSiOns regardless of the direction
to be protected such as an arm or mast movable with
respect to a base or other support. It preferably in
cludes means for interrupting the arm drive motion before
the arm itself contacts the obstruction.
According to one embodiment of the present inven
from which the device approaches the obstruction.
A variety of devices have been proposed ‘for limiting
the motion of moving elements with respect to other ob
jects. Among such devices are the limit switches used 15 tion there is provided a detector means such as a series
in elevators, cranes and the like {for preventing‘ the ele
vator car from striking either the top or bottom of the
elevator shaft. Another class of devices includes strate
of detector wires or cables extending parallel to the lon
gitudinal axis of the moving device or arm for which
protection is desired and arranged so as to provide a
gically located signaling probes which project outwardly
protective detector envelope or cage spaced from the
from vehicles such as lift trucks or automobiles and 20 device. The wires are secured at each end to ring like
are used to detect the approach of an obstruction such as
support members which are in turn ?exibly and resiliently
acurbstone.
mounted near the ends of the device to be protected. In
'In contrast, with the prior art, the present invention is
the preferred embodiment of the invention, one of the
directed toward providing a means for detecting collision
support members is designed to operate sensor means
between obstructions and a device for which protection
such as electrical switches whenever the detector means
is desired even though the direction from which the de
and support means is de?ected by engagement with an
vice approaches the obstruction cannot be exactly antici
obstruction. The switch can thus stop any or all drive
plated. A ‘further provision of the present invention
motions ‘for the device before the device itself contacts
includes means for automatically stopping the motions
of the device protected before a collision occurs.
the obstruction. The resiliently mounted detector rings
The 30 may also be provided with sensing means such as rods
present invention is particularly valuable for applications
in protecting bodies movable in several directions with
respect to a base, such as the moving arm or mast por
or the like which extend the collision detecting envelope
beyond the ends of the arm. A provision is also made
so that when either of the Support means is struck, it
will tilt, and as a result of the linkage through the de
’ tector envelope, the other spring mounted ring will be
tion of hoists, cranes, mechanical arms and the like.
In recent years remote handling epuipment has be
come an important phase of the atomic industry among
caused to tilt so that the sensor means are always ac
tuated no matter where contact takes place between the
Others. Included in such remote handling devices are
envelope and the obstruction.
crane hoists, underwater corrosion resistant manipulators,
manned and unmanned mobile manipulators, fuel han
This invention will be best understood from the illus-.
dling devices and mechanical arms. The mechanical arm 40 trations in the accompanying drawings showing one form
of apparatus according to the present invention is which:
is a remote controlled device which will duplicate one
or more motions of the human arm and hand with ex
treme accuracy. Because of the precision tolerancesv
maintained in these devices, it is highly desirable to pro
tect them from potentially damaging collisions.
The
term “arm” as used herein is de?ned as any elongate
rember attached movably to a frame or base and is
meant to include masts, booms and the like. It will be
appreciated that as a result of the large number of pos
sible motions of the several parts of the arm, occasionally
when operated by remote control the arm may strike an
obstruction unnoticed by the operator. Furthermore, it
is impossible to anticipate which part of the arm will
contact the obstruction. Therefore,- to protect the arm
from collisions, it is desirable to provide means for de
tecting and preventing contact with obstructions on all
sides of the arm. The protector must be reliable in op
eration, light in weight, positive in action and should
FIG. 1 is a side elevation of a mechanical arm utilizing
one form of apparatus embodying the present invention.
FIG. 2 represents a perspective view partly in section
illustrating another form of apparatus in which the col
lision preventer according to this invention may be uti
lized.
FIG. 3 is a side elevation of one form of apparatus
in accordance with this invention which may be used with
either of the devices illustrated in FIGS. 1 and 2.
FIG. 4 is a plan view taken along line 4-4 of FIG. 3.
FIG. 5 is a side elevation partly in section of a support
plate mounting spring.
With reference to these ?gures, there is shown in
FIGURE 1 a mechanical arm 1 having a cylindrical upper
arm member 2 ?xed rigidly to a suitable shoulder or over
head supporting framework 4. Mounted at- the lower end
of upper arm portion for rotation about the longitudinal
axis of the upper arm member is a pivot support member
remain undamaged after engagement with an obstruction.
It is an important object of this invention to provide 60 7. Rotation of the pivot support member 7 is carried out
by electric motors inside the upper arm 2 and is con
an improved collision sensing envelope for a material
trolled by means of a remotely placed motor control.
handling device, which is external to and extends almost
Secured rigidly to the pivot support member 7 is a lower
completely around the device to be protected.
arm pivot bearing 3. Pivotally mounted on the lower
‘It is another object of this invention to provide an im
' arm pivot bearing 3 for motion about an axis transverse
proved collision preventer which readily senses an im
pending collision and promptly stops the motion of the
to the arm is a lower arm, member 16 having a pair of
device to be protected before damaging contact occurs.
It is a ‘further object of this invention to provide an
improved collision preventer of a mechanical type which
is very reliable and wherein collisions are non-damaging 70
jaws ‘5 extending therefrom. The jaws 5 are rotatably
both to the protection device and to the device protected.
‘It is still another object of this invention to provide
venter mechanism designated 6 is suspended from the
lower arm 16 and will be described in detail below.
mounted with respect to the lower arm 16 and may be
rotated as well as opened and closed by a remotely con
trolled motor recessed ins‘ide the arm. The collision pre
3,053,945;
3
Referring now to FIGURE 2, there is shown another
4
Springs 26 are mounted in a manner similar to that here
device embodying the present invention which is generally
inbeforc explained in connection with spring 25.
similar to an overhead crane 10 comprising a bridge 11
brackets mounted on the detector rings 20 and 21 are
supported at either end by wheels .12 resting. on tracks
motor (not shown) for moving the carriage 9 with respect
also positioned farther from the axis of the arm than those
on the arm. Thus, it will be noted that the springs are
inclined at an acute angle with respect to the axis of the
mast, and the ends thereof connected to rings 20 and 21
are spaced further apart than the ends connected to the
to the beam 11. Extending vertically downward and up
arm. The springs 25 and 26 thus simultaneously suspend
13 and 14 and a carriage 15 having wheels mounted on
the bottom thereof for carrying the carriage 15 across
beam 11. Inside the carriage 15 is provided an electric
The
ward from the carriage is a cylindrical arm or mast 16a 10 the detector envelope movably, center the detector enve
which may be elevated or lowered by any suitable means
lope with respect to the arm axis, and maintain tension
known to the art such as by an electric motor geared
on the cables so that any cable movement results in a
to a rack extending the length of the arm. At the bottom
corresponding ring movement.
of the arm may be provided any desired variety of sens
Attached rigidly to arm 16 above de?ector ring 20 and
ing or lifting mechanism 17 such as a pair of jaws or the 15 spaced therefrom is a switch support member 40. Sup
like. For purposes of illustration, an ionizing radiation
port member 40 may be mounted at any convenient po
sensing probe is shown. Conductors for carrying the cur
sition on the ‘arm and the length of cable 19 adjusted to
rent to the sensing mechanism may be recessed inside the
maintain ring 20 at the desired distance from support
arm 160. By means of such a device, measurements may
member ‘40. Mounted at equally spaced apart intervals
be taken or articles may be picked up and moved about 20 on the periphery of the support member 40‘ are four
and positioned with accuracy.
pairs of electrical switches 42, and 42a, 43 and 43a, 44
The collision detecting mechanism used in the devices
and 44a, 45 and 45a. Conductors 46 wired to the switches
illustrated in FIGURES l and 2 will now be described in
are connected in series with the drive motor (not shown)
detail in which the same numbers refer to corresponding
which is used for moving the arm. These switches are
parts. With particular reference to FIGURES 3 and 4, 25 preferably maintained in a normally closed position so
there is shown at the top and bottom of arm 16 a pair of
that the circuit carrying current to the drive motor is
?at support members or rings 20 and 21 respectively.
Each of rings 20 and 21 has a hole in the center thereof
complete. If, however, the switches are opened, current
to the drive motor will be interrupted and the motion of
designated 22 and 23 respectively. Arm 16 passes through
the arm is thereby stopped. Each switch has ‘a button
the center of holes 22 and 23. The holes are preferably 30 50 on the lower side thereof which, when moved slightly
substantially larger in diameter than the diameter of the
will turn the switch on or off. The position of the ring
arm. For example, they may be on the order of one and
20 is so adjusted that the upper surface thereof contacts
one half times the diameter of the arm. The size of the
all of the several switch buttons and maintains the
holes is not critical but is preferably larger in cases in
switches in the closed position.
which the arm is designed to operate at relatively high 35
Switches 42, 43, 44 and 45 are opened when their re
speeds or when movement of the mast cannot be stopped
spective buttons 50 are released and switches ‘42a, 43a,
rapidly as explained more fully hereinbelow. The shape
44a and 450 are opened when their respective buttons
of the detector ring in plan view is illustrated as octagonal,
‘50 are depressed. As a result, one switch of each pair
however the shape is not critical and it could be round or
will be opened whether the portion of ring 20 adjacent a
square if desired.
40 given pair of switches is depressed or elevated thereby
Ring 20 is ?exibly and resiliently suspended from arm
assuring reliable performance. -It will be seen that when
16 by eight helical springs 25 each connected at one end
to the arm 16 above ring 20 and at the other end to the
detector ring 20. Ring 21 is suspended in a similar
any of the cables or rings are de?ected by an obstruc
tion or in any way caused to move relative to mast 16,
plate 20 will also move so that at least one switch button
manner by eight helical springs 26 each being attached 45 will be depressed or released thereby opening the cir
to the ring 21 at one end and to the arm 16 below the
cuit to the drive motor. For example, if ‘a foreign ob
ring at the other end. Extending between ring 20 and 21
ject or obstruction strikes one or more of the cables on
substantially parallel with the arm 16 is a detector means
comprising a plurality of detector cables 19. The detector
cables 19 are spaced apart and attached at each end to the
the right side of the apparatus in FIG. 3, the lower ring
The four brackets designated 29 attached to the arm are
and stopped. If this distance is fairly great, the envelope
and holes in rings 20 and 21 should be spaced further
will tilt counterclockwise and the upper ring will tend to
tilt clockwise activating switches 42 and 4411. If the ca
outside edges of the rings 20 and 21 thereby surrounding
bles are struck from the front in FIG. 3, switches 43 and
the arm throughout almost its entire length so as to form
45a ‘will be activated. [It will be noted that if either of
a cage or envelope around the arm. Rigidly attached
the rings itself is hit from the side and moved laterally,
to the periphery of detector ring 21 and extending down
a tilting action will still take place because of the fact
wardly therefrom are a plurality of spaced-apart sensing 55 that the ends of the springs mounted to the arm (since
rods 24, four such rods being shown.
they are closer together than the ends mounted on the
As shown in detail in FIG. 5, each of springs 25 and
rings) form a pivot point about which the rings turn
26 is ?tted at either end with a spring retainer 27 and a
even though displaced laterally. Thus when ring 21 is
threaded eyebolt 2S screwed into the center of the retainer
struck from the right side in FIG. 3 and displaced lat
27. The eyebolts extending upwardly from the springs
erally to the left, it will rise on the right side and de
designated 25 are connected to spring brackets 29 which
scend on the left side, thereby tilting plate 20‘ by virtue
are attached rigidly to the arm. The eyebolts extending
of a connection through cables 19 in a counterclockwise
downwardly from spring 25 are connected to suitable
direction (as seen in FIG. 3). This tilting causes the
buttons of switches 44 and 44a to be depressed and the
brackets 30 attached securely to detector ring 20. Similar
ily, the eyebolts 28 attached to springs 26 at their lower
buttons of switches 42 and 42a to be released.
ends are connected to brackets 35 attached rigidly to the
‘In determining how far the protective envelope should
arm and those attached to the upper end of the springs are
be spaced from the device to be protected, one ‘must con
connected to brackets 36 mounted on detector ring 21.
sider the distance in which the device can be decelerated
spaced axially apart from, and positioned circumferential
ly between the four brackets 30‘ attached to the arm. Each
bracket 29 thus has two springs 25 attached thereto and
each such pair of springs diverges so that the lower ends
from the arm 16 so that the device can be stopped before
collision takes place between the obstruction and the arm
or between the rings and the arm.
thereof are attached to brackets 30 on either side of the
A number of variations ‘are possible in the present in
bracket 29 to which the upper end thereof is attached. 75 vention. The electric switches, for example, can be re
3,053,94e
6
placed by pneumatic or hydraulic valves if desired. This
change would be preferred if the drive mechanism were
operated by pneumatic or hydraulic actuators. Elec
tric switches, of course, are preferred when the drive mo~
tor or mechanism is electrically operated. The switches
are movably mounted and normally held in one position
with respect to said elongate body, detector means extend
ing from one said support to the other said support, and
electric switch means operatively associated with said
body and said ?rst support member whereby displace
ment of said ?rst support with respect to said elongate
body activates said switch means.
6. A collision detector comprising a movable arm to
in the present illustration or on the cage or envelope or
be protected, a ?rst support member encircling one end
a portion thereof or on the detector ring.
10 of said arm and spaced therefrom, a second support
The suspension means have ‘been illustrated as springs,
member encircling the other end of said arm and spaced
but it is apparent that other resilient and extensible or
therefrom, a plurality of spaced apart springs disposed
about the circumference of each said support, said springs
?exible devices may be used to accomplish the same re
being connected at one end to said support and at the
sult. For example, sponge rubber mounts may be used
or a form of rubber tubing may be used, if desired. A 15 other end to said arm, the axis of each such spring in
tersecting the axis of said arm at an acute angle, the
form of gimbal mechanism may be substituted for the
springs but it should be noted that the gi-mbal mecha
ends of said springs connected to said support being
spaced relatively far apart and the ends of said springs
nism must be designed so as to enable the protective en
velope to be moved in all directions including vertically
connected to said arm being spaced relatively close to
and must also be provided with a'centering means.
20 gether, and a plurality of electric switches operatively
The detector means or envelope has been illustrated
associated with said support and wired in the circuit con
trolling the driving mechanism for said arm whereby dis
as a plurality of parallel cables extending ‘from a ring at
the lower end of the mast to a ring at the upper end of
placement of said support with respect to said ‘arm causes
said arm to stop moving.
‘
the mast, but a number of other variations are possible.
themselves may be either normally open switches or nor
mally closed switches. The switches may be mounted on
either the device to be protected, that is the mast or arm
'For example, a ?exible screen or mesh could be substi
tuted for the cables and if the obstructions likely to be
encountered are pointed projections having a small area
at the end, a tube of material such as cloth or plastic
7. A collision preventer comprising an arm to be pro
tected, a movable support ring encircling one end of said
arm and spaced therefrom, resilient suspension means for
said ring connected between said ring and said arm where
?lm could be used which would have the advantage of
by said ring is movably mounted and normally held in
forming a continuous envelope around the device to be 30 one position with respect to said arm, ?exible detector
protected. Thus, no matter how small the obstruction
means surrounding said arm ‘and connected between said
was, it could not collide with the device without ?rst
ring and the other end of said arm and sensor means
striking the detector.
connected to said arm to halt the motion of said arm
responsive to displacement of said ring with respect to
vIn view of the principles set forth herein, we have
shown some of the ways of carrying out the present in
said arm.
vention and some of the equivalents which are suggested
8. A collision preventing mechanism comprising a
by these disclosures.
framework; an elongate arm connected to said frame
We claim:
work, said arm being movable with respect to said frame
‘1. A collision preventer comprising an arm to be pro
work; a drive mechanism for moving said arm; switch
tected, ?rst and second movable support means encircling
means for starting and stopping said drive mechanism;
said arm and spaced therefrom, resilient suspension
detector means extending along the length of said arm
means for said support means connected between said
and surrounding said arm for transmitting relative mo
support means and said arm normally holding said sup
tion between foreign objects and said arm to said switch
port means in one position on said arm whereby said sup
means, said switch means being activated when a foreign
port means may be displaced with respect to said arm, a 45 object strikes said detector means, said detector means in
plurality of detector means extending from said ?rst sup—
cluding an axially extending detector element and a
port means to said second support means and a sensor
movable support member connected to and supporting
means operatively associated with said arm and said sup
one end of said detector element, and suspension means
port means for detecting relative displacement between
connected at one end to said arm and at the other end
either of said support means and said arm.
to said support means ‘for mounting said support means
2. A collision preventer according to claim 1 ‘wherein
movably and normally in one position with respect to
said resilient suspension means comprises a plurality of
said arm.
spaced apart springs disposed about the circumference of
9. A collision preventer according to claim 1 wherein
each said support, each such spring being connected at
said arm has connected at the free end thereof a gripping
one end to one said support and at the other end to said
device and wherein one said support means has connected
arm.
thereto a plurality of elongate sensing members disposed
laterally from said gripping device.
3. A collision preventer according to claim 1 wherein
said sensor means comprises means for making and break
ing an electric circuit operatively connected between said
support means and said arm whereby displacement of said
support with respect to said arm activates said circuit
making and breaking means.
4. A collision preventer according to claim 3 wherein
said circuit making and breaking means comprises a plu
rality of electric switches wired in series with the drive
mechanism for said arm.
‘5. A collision preventer comprising an elongate body
to be protected, a ?rst movable support member encircl
ing one end of said elongate body and spaced therefrom,
a second movable support member encircling the other
end of said elongate body and spaced therefrom, a plu
rality of spaced apart resilient suspension members dis
posed about the circumference of each said support and
connected at one end to one said support and at the
'10. A collision preventer comprising an arm to be pro
tected, ?rst and second support means encircling said
arm and spaced therefrom, resilient suspension means
for said support means connected between said support
means and said arm normally holding said support means
in one position on said arm whereby said support means
may be displaced with respect to said arm, said resilient
suspension means comprising a plurality of spaced apart
springs disposed about the ‘circumference of each said
support, each such spring being connected at one end to
one said support and at the other end to said arm, each
such spring intersecting the axis of said arm at an acute
angle, the ends of said springs connected to said support
being spaced relatively farther apart than the ends of
said springs connected to said arm, a plurality of detector
means extending from said ?rst support means to said
other end to said elongate body whereby said supports 75 second support means and a sensor means for detecting
l
3,058,948
8
relative displacement between either of said support
ment of said support with respect to said arm activates
means and said arm.
said circuit making and breaking means, said circuit mak
ing and breaking means comprising a plurality of electric
11. A collision preventer comprising an ‘arm to ‘be
protected, ?rst and second support means encircling said
arm and spaced therefrom, resilient suspension means for
switches wired in series with a drive mechanism for said
arm, said electric switches comprising four pair of equal
ly spaced apart switches, one switch of each pair being
opened when the switch element thereof is depressed and
said support means connected between said support means
and said arm normally holding said support means in one
the other switch of each pair being opened when the
switch element thereof is elevated.
position on said arm where-by said support means may
be displaced with respect to said arm, a plurality of de
tector means extending ‘from said ?rst support means to 10
said second support means and a sensor means for de
tecting relative displacement between either of said sup
port means and said arm, said sensor means comprising
2,433,028
means for making and ‘breaking an electric circuit and
means operatively associated therewith whereby displace
References Cited in the ?le of this patent
UNITED STATES PATENTS
15
2,942,736
Clapper _____________ __ Dec. 23, 1947
Landsiedel et al _______ __ June 28, 1960
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