Note: Descriptions are shown in the official language in which they were submitted.
11/5/85 A P P L I C A T I O N
OPERATOR CONTROL SYSTEM
BACKGROUND OF THE INVENTION
This invention relates to controls for industrial lift trucks, and more
particularly to an operator's manual control and to hydraulic, speed and
directional functions controlled thereby.
The prior art includes various means which are intended to provide
manual controls for reducing operator fatigue and single multi-function
control assemblies. Exemplary of such prior art are U.S. Patent Nos.
3,811,336 and 3,937,294.
SUMMARY OF THE INVENTION
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The invention is concerned with human engineering and control functions
;n the manual control of a plurality of powered funct;ons in the exe~plary
environment of a stand-up rider type industrial lift truck. An operator's
handle assembly is designed and located so that the functions to be
controlled are sense oriented, operator fatigue tends to be minimized
whether the operator is dr~ving the truck forwardly or rearwardly, and a
support for the operator is provided during travel operations in either
direction. The operator's control handle assembly is designed to be
located in the operator's compartment on a bias to the longitudinal axis o~
the truck so that when in normal operating position it is not necessary
that the operator turn his body to any substantial degree, but ~erely his
head, in looking forwardly or rearwardly in those directions of truck
operation
The manual control handle ls designed to operate linearly along the
axis of a shaft in either direction in order to perForm a multiplicity of
hydraulic functions such as li~t and lower, reach and retract, tilt
forwardly and rearwardly, and side shift of the load support to the right
and to the left. Electric relays are provided in an electric control
system which is operatively connected to the manual control and to the
hydraulic system whereby a single hydraulic valve may control any or all of
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the above hydraulic functions by the operator control handle as it is rnoved
linearly along the shaft forwardly and rearwardly from a neutral posit;on,
said relays being armed for selected functions by means of conveniently
located switch controls on the operator control handle. Directional
control and truck speed control is provided by rotating the handle in
either direction about its own axis from any position of displacement
thereof along the shaft. The control is located in a recessed compartment
which provides protection both for the operator and for the control, and it
is an aesthetic pleas;ng design.
It ;s a pr;ncipal object of the ;nvention to provide a manual control
for l;ft trucks, and the like, which utilizes human eng;neer;ng principles
so as to minimize operator fatigue during operat;on of the truck under all
conditions.
It is an important object to provide such a manual control in which two
basic motions only of the control by the operator are adapted to control
all operating functions of the truck except steer;ng, the hydraulic control
funct;ons be;ng selectable at the control handle and operative
one-at-a-time by the same control handle movements.
It is another object to provide cooperat;ng electrical and hydraulic
systems controlled by the control handle, the hydraulic system components
which perform various hydraulic functions being controlled by a single
valve and the hydraul;c system components being interlocked with the
electrical system such that the hydraulic functions are operable in any
sequence, but only one-at-a-time.
Other objects, features and advantages of the invention will appear in
the detailed description which follows when taken in conjunction with the
accompanying drawings, wherein
BRIEF DESCRIPTION OF THE DRAWING
. _ _
FIGS. 1 and 2 are simplified line drawings of a stand-up rider lift
truck in side and plan views, respectively;
FIG. 3 is a broken away view of the operator's compartment;
FIG. 4 is a perspective view showing the operator's handle control
assembly in exploded v;ew;
FIG~ 5 is a schematic view of the major components of the hydraulic
system; and
FIG. 6 is a schematic view of the major components of the electrical
system which is operatively connected both to the hydraulic system and to
the manual control.
DESCRIPTION OF THE PREFERRED EMBODIMENT
.. _ . . .. _ _
Referring now in detail to the drawing, and first to FIGS. 1 and 2, a
stand-up rider lift truck is shown generally at numeral 10. It utilizes,
as is usual, a wheel supported body section 12, upright 14, an operator's
compartment 16, outr~gger arms 18 extending forwardly of the body section,
and a fork carriage 20 mounted at the outer end of a reach pantograph 22
which is in t~rn mounted at its inner end to a carriage supported from the
telescopic ~Ipright, all in known manner.
In the operator's compartment is located a rotatable operator's
steering control 24, a service brake pedal 26, and the operator's control
assembly 50 of this invention. In known manner, a pair of reach cylinders
30 are mounted to extend and retract pantograph 22, a pair of tilt
cylinders 32, one of which is shown, are mounted at the forward end of the
pantograph for tilting the fork forwardly or rearwardly, and a side sh;ft
cylinder 34 is mounted on the fork carrier to side shift the fork assembly
to the right or to the left.
Referring now to FIGS. 3 and 49 the operator's manual control assembly
is shown generally at numeral SO. It comprises a support bracket 52 for~ed
as shown having a horizontal portion 54 mounted to a base plate beneath the
operator's control by a plurality of bolts, a vertical section 56 having a
relatively high rear end and low front end in order to provide for a
downward tilt of the handle assembly, and a pa;r of outwardly extending
ears 58 for receiving in openings thereof a control shaft 60. A control
handle 62 is mounted by a projecting shaft 64 in opening 66 of a housing
portion 68, the control handle and housing being mounted from control shaft
60 by a transverse portion 70 of the housing through which extends shaft 60
in opening 72.
The mounting bracket 52 is located at a bias to the longitudinal axis
of the truck, the vertical portion 56 thereof being formed to extend
forwardly and do~nwardly so that the handle control portion 62,68,70 is
designed to be located at its most convenient and comfortable position in
the operator's compartment. Manual control ;s effected whether operating
the truck in a forward or rearward direction by movement of the handle
control along the downward tilt and inward bias of shaft 60; this provides
good operator "sense" control as the handle is actuated forwardly,
downwardly and inwardly, or rearwardly, upwardly and outwardly along shaft
60 to control the various hydraulic functions of the lift truck, as best
shown in FIG. 5, all as will become more apparent as the description
proceeds.
All hydraulic functions of the truck except steering are controlled by
means o~ a single spool valve 74 which is connected at i~s one end to a
pair of links 76 in ~urn connected together through an opening in a boss at
the end of a control lever 78 which extends outwardly of one side o~ a cast
valve control lever 80 mounted for pivotal movement on a pin 82 which is
secured in an ear ~4 of bracket 52. Lever 80 extends through an opening 86
in bracket portion 56 and is mounted on the one end of an angled control
rod 88 which is mounted in an opening of an upwardly extending handle
housing control portion 91 such that when the handle control 62 is actuated
linearly in either direction along shaft 50 the horizontal portion of
control shaft rod 88 causes lever 80 to pivot in one direction or the other
a distance which is proportional to the distance handle 62 is actuated
along shaft 60 as the vertical portion of rod 88 pivots in housing portion
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91, thus causing spool valve 74 via the resulting pivotal movement of lever
78 and links 76 to be actuated a similar proportional distance to actuate
spool valve 74 thus to control the velocity of movement of the various
hydraulic actuators illustrated in FIG. 5.
Control rod 88 is an impor~ant element in the manual control assembly
50 in that in the configuration and mounting of assembly 50 as disclosed,
control rod 88 performs two important functions, viz, by its angled
connection between housing portion 91 of handle control portion 62,68,70
and pivoted control lever 78,80 it both prevents handle control portion
62,68,70 from rotating on shaft 60 and actuates control lever 78,80 about
! pin 82 out of a neutral position in one direction or the other when the
handle control portion is actuated linearly along shaft 60 in either
direct;on thus actuating spool valve 7~ as selected.
It will be noted that as the handle control is actuated forwardly along
shaft 60 the vertical portion of rod 88 pivots about its axis in housing
portion 91 in a counterclockwise direction, FIG. 4, while the horizontal
portion thereof is thereby actuated to swing forwardly, thus pivoting lever
78,80 about pin 82. Reverse movements of the above mentioned parts occur
when the handle control is actuated rearwardly along shaft 6~.
A hydraulic control switch assembly 90 is mounted in a housing 92
located at one end of the control handle in a convenient position. It is
operatively connected by an electrical control conduit 95 which extends
through handle 62,64 and housing portion 68 to an electric control circuit
system as shown in FIG. 6. A horn button 93 is mounted on the back side of
the switch control assembly. A hydraulic function button 94 is moun~ed on
the compartment cover panel for a purpose to be described.
A manual toggle switch 96 is mounted in housing 92 and ~s adapted to
operate through a contactor box 98 connected through the various lea~ wires
in conduit 95 to certain circuits in FIG. 6. Toggle 96 is normally located
in a neutral position as shown at which movement of control handle 62
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rearwardly along shaft 60 effected by a pulling motion of the operator
effects through the circuits of FIGS. 5 and 6 via spool valve 74 a lifting
function of the upright 14, whereas forward movement thereof on shaft 60
effects a lowering movement of the upright. The fork tilt function is
controlled at toggle 96 by operator's thumb actuation of switch portion 100
which suitably conditions a tilt circuit in FIG. 6 to permit only a ~ilting
function, all other hydraulic functions being locked out by suitably
conditioning the electrical control circuits in FIG. 6 which energize the
solenoids of the other function selector valves in ~IG. 5. Forward
movement of control handle 62 along shaft 60 effects operation of spool
valve 74 in one direction which causes the fork to tilt forwardly relative
to the upright whereas rearward movement along shaft 60 moves valve 74 in
the opposite direction which causes the fork to tilt rearwardly. Actuation
of the toggle portion 102 conditions the circuit of FIG. 6 to condit~on the
circuit of FIG. 5 for extension and retraction of the pantograph 22 With
switch portion 102 actuated, forward actuation of handle 62 causes
extension of the pantograph while rearward actuation thereof causes
retraction via actuation of spool valve 74 and the conditioning circuits of
FIG. 6 to condition the selector valves of FIG. 5 to limit the hydraulic
function to operation of the pantograph Actuation of button 94 likewise
conditions the circuits of FIGS. 5 and 6 to control side shifting of the
fork to the right and to the left. To side shift left with button 94
depressed handle 62 is actuated forwardly and to side shift right with
button 94 depressed handle 62 is actuated rearwardly. It will be noted
that the longitudinal bias of shaft 60 from right to left as mounted in
bracket 52 conforms also to the sense of the operator in respect of right
and left side shift movements.
To reiterate, the control circuits of FIGS. 5 and 6 are so designed
that no two hydraulic functions can be performed simultaneously~ all but
the selected one being locked out of circuit operation as will be described
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in more detail below. However, the direction and speed controls are
independent of the circuits of FIGS. 5 and 6 and can be operated during the
operation of any given hydraulic function.
A direction and speed control switch box is shown at 104, FIG. 4. It
S is mounted to a plate 106 which is supported from a portion 108 of housing
6~, contactor box 104 being suitably connected as shown in FIG. 4 to
control levers 108 and 110. Rotary actuation of handle 62 causes the
projecting shaft 64 thereof to actuate lever 110 which in turn is
operatively connected to lever 108 so that actuation thereof conditions the
respective direction and speed control circuits of FIG. 6 to operate the
truck forwardly or rearwardly at a selected speed which is a function of
the degree of rotat~on of handle 62 about its axis. Forward or
counterclockwlse rotation of handle 62 conditions the truck for forward
operation at a selected speed while rearward or clockwise rotation
conditions the circuit for rearward operation of the truck at a selected
speed. Control box 104 produces a variable voltage to an SCR control 152,
the volta~e being established by the degree of rotation of the shaft in
item 104. The rotation of the latter shaft also actuates switches which
control the travel direction of the truck.
Referring again to FIG. 5, prime mover driven lift, steer and auxiliary
pumps are shown at 120~ 122, and 124 respect1vely. A hydraulic reservoir
is illustrated at~ A steer valve and control is illustrated
schematically at 128 wherein the operator steering control 24 is shown.
The manually controlled spool valve 74 is shown in circuit with a lift
selector valve 126 which controls the operation of a lift cylinder 128, a
tilt selector valve 130 which controls the operation of the pair of tilt
cylinders 32, and a side shift selector valve 134 which controls at the
operator's option either the pair of pantograph reach cylinders 30 or the
fork side shift cylinder 34. A double check and dump valve 139 controls
fluid flow from pumps 120 and 124. One of the check valves in valve 139 in
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circuit with spool valve 74 prevents fluid flow from pump 124 back through
pump 120 and the other check valve prevents fluid flow from pump 120 back
through the dump valve of valve 139. A line dump valve 141 is also in
circu;t as shown with spool valve 74 and the various selector valves; lt
limits hydraulic pressure to 50 psi in the upright hoses, not shown, except
when an auxiliary hydraulic function (reach, tilt or side shift) is
operative. A double pilot operated check valve 143 prevents fluid flow
from such auxiliary function actuator cylinders 30, 32 and 34 except when
the other side of any of said actuators is pressurized.
Each of the above ment;oned valves, except spool valve 74 and check
valve 143, are solenoid actuated as illustrated. As ~hown in FIG. 5 all of
the selector valves 126, 130 and 134 are in condition such that actuation
of spool valve 74 by actuation of control handle 62 along shaft 60 ;n a
rearward direction will effect elevation of lift cylinder 128 and of the
upright 14, whereas forward movement of control handle 62 will effect
lowering movement of the lift cylinder and the upright. The normal
condition of the FIG. 5 circuit is as illustrated. As will be apparent,
upward movement of valve 74 connects lift pump 120 to the lift cylinder v;a
valve sections 144 and 142 of valves 74 and 126, respectively, whereas
lowering ~ovement of the lift cylinder is effected by actuation of control
handle 62 forwardly which effects downward movement of valve 74 and
lowering of the lift cylinder via valve sections 140 and 142 of said
valves, said other selector valves 130 and 134 being rendered inoperative
by the position of lift selector valve 126.
I~ any one of valves 130 or 134 is condit;oned by operat;on of toggle
switch 96 or button 94 to tiltl reach or side sh;ft then li~t valve 126 is
actuated to make operative a valve section 146 which by-passes the circui~
to lift cylinder 128 and connects through pilot check valve 1~3 with either
tilt cylinders 32, reach cylinders 30 or -side shift cylinder 34 depending
upon the condition of the circuit of FIG. 6 as related to the operation of
toggle 96 or switch 94, as previously described.
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Referring now more specifically to FIG. 6, the drive motor circu;t and
assembly is schematically illustrated at numeral 150, an SCR drive motor
speed control generally at 152, and directional switch and control at 153
and 160 having an SCR control card for directional and speed control at
155. Power ~teer and pump motor circuits are shown at 154 and 156,
respectively, and a 24 volt battery supply at 158. Inasmuch as the
aforementioned circuits have no specific bearing upon the invention they
have been schematically ;llustrated only in part.
All of the switches and contactors in circuit are shown in their
normally open or normally closed positions. With the drive motor circuit
150 ~n operation, handle control 62 operates forward or reverse switches
153 initially upon rotary movement in one direction or the other of control
handle 62 whereupon the lift truck may be operated in one direction or the
other at selected speeds via directional switch 153 and speed control
160,162,163 operating through speed control switch box 104 and its
operative connection to control handle 62 via levers 108 and 110. Below
speed control coil 162 ls located in the circuit schematic a plurality of
circuit lines, switches and relay coils as identified by legends on the
circuit lines. A plurality of switches identified by odd numbers and
letters from 3A,3B through 9A,9B are controlled by toggle 96 and button 94
to condition the various solenoid actuators of the respective selector
valves of FIG. 5 so that one selected hydraulic function only may be
operative at a given time. More specifically, the lift cylinder is
operated to elevate when the operator pulls back the control handle along
shaft 60 from its neutral position which initially closes one set of
contacts in a valve spool switch 170 which then applies voltage to a
terminal 172 on an electronic timer 174 which then applies voltage to relay
coils 3A and 3B which conditions all 3A and 3B contactors to open or close
from the normally closed or open positions illustrated to complete the
circuit to the lift motor contactor coil turning it on so that pressure
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fluid ;s d;rected to lift cylinder 128 from pump 120 through spool and lift
valves 74 and 126. Certain contactors 3A and 3B are open which prov;de an
electr;cal interlock prohib;tlng other hydraulic functions from being
performed simultaneously. Lift speed is controlled by the spool of valve
74 as a function of the displacement of control handle 62 rearwardly along
control shaft 60 from its neutral posit;on.
To lower the lift cylinder and upright the operator displaces control
handle 62 forwardly of its neutral pos;t;on on shaft 60 thereby in;t;ally
clos;ng the other set of contacts ;n sw;tch 170 which aga;n applies voltage
to term;nal 172 and thence to contactors 3A and 3B. However, the c;rcu;t
to the l;ft motor contactor co;l ;s not completed because a rectifier 180
at switch 170 blocks current flow to the closed contactor 3A in that
circuit prevent;ng the operation of l;ft pump 120. Aga;n, certain
contactors are open which provide an electrical ;nterlock prohib;ting other
hydraulic functlons from be~ng performed simultaneously.
It should be understood that whenever the operator selects a hydraul;c
function via any one of the selector valves~ movement in either direction
of the control handle always initially closes switch 170 in one direction
which ;s circuited through certa;n of the contactors, depending on the
funct;on selected, to always initially energize soleno;d 141a which closes
line dump valve 1~1 thus permitting pressure fluid flow solely to the
selected actuator cyl;nder. In respect of each and all hydrau!ic selector
valve operat;ons the electron;c t;mer 174 funct;ons whenever the contrdl
handle ;s returned to a neutral pos;tion to keep open the prior actuated
selector valve for a very br;ef per;od of t;me (such as 1/10 second) so
that system l;ne pressure can dump to a low pressure (such as 50 psi) prior
to operatlon of the next hydraulic function selected when the control
h~ndle is again moved out of neutral. Hydraulic functions can be selected
only when the control handle is ;n neutral.
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Retracting an extended pantograph 22 is accomplished when the operator
depresses the reach/retract portion 102 of toggle 96 and pulls back on
control handle 62 which actuates portion 144 of valve 74 into an operative
position. Depressing switch portion 102 energizes relay coils 5A and 5B.
Certain contactors 5A and 5B close which energizes the solenoid of dump
valve 139 which directs pressure fluid from pump 124 to valve 74O Switch
portion 102 can be released by the operator after the control handle is
initially moved to close the contacts in valve spool switch 170 without ~-
interrupting the retract function. Other contactors SA and 5B are opened
l which provide an electrical interlock which prohibits other hydraulic
functions from being performed simultaneously. Still other contactors
5A,5B close which actuate the selector valve solenoid at valve 126 thus
directing pressure ~luid to retract cylinders 30 while the same conditions
pertain as above to retract cylinders 30. The speed of retraction of the
lS pantograph is controlled by the displacement of control handle 62
rearwardly from a neutral position.
The reach function of the pantograph is activated in a similar manner
when the operator depresses toggle portion 102 and pushes the control
handle forwardly which closes the opposite set of contacts in switch 170,
The fork tilt back function is performed when the operator depresses
portion 100 of toggle 96 and pulls rearwardly control handle 62 to actuate
switch 170 and engage portion 144 of valve 74. This energizes relay coils
and contactors 7A and 7B, certain of which close~to energize the relay
coils of the lift valve solenoid to engage valve portion 146 and the tilt
selector solenoid to engag2 valve portion 129 as well as that o~ dump valve
139, thus retracting cylinders 32. Other contactors 7A and 7B close which
permits portion 100 of toggle 96 to be released without interrupting the
tilt back function as above described. Again, contactors are conditioned
to prohibit other hydraulic functions from being performed simultaneously
as above described. Tilt speed is controlled by valve spool position
related to control handle displacement rearwardly from a neutral position.
The tilt forward function is performed by the operator by again
depressing toggle switch portion 100 and push;ng the control handle
forwardly from its neutral position, the same conditions exist;ng as for
tilt back except that valve portion 140 of valve 74 is engaged.
The side shift right function is performed by the operator depressing
but~on 94 and pulling rearwardly the handle on shaft 60 which energizes
relay coils and contactors 9A and 9B and engages valve portion 1~4.
Specific contacts 9A and 9B close which energizes the solenoid of dump
valve 139, and the solenoid of the lift selector valve to engage valve
portion 146 of the lift selector valve and the solenoid of the side shift
selector valve 134 to engage valve portion 136. Another set of contacts 9A
and 9B close ~hich permits the operator to release button 94 fcllowing
actuation of the control handle rearwardly to close contacts in valve spool
switch 170 without interrupt;ng the side shift right function. Other
contacts 9A and 9B are open which provide an electrical interlock
prohibiting other functions from being performed simultaneously as above
descr1bed. The side shift speed is controlled by the displacement of the
valve spool position from neutral as above described.
The side shift left function is performed the same as the side shift
right function above described except that valve portion 140 of valve 74 is
engaged.
At any longitudinal control position of the control handle 62 on shaft
60 in the operation in any one of the above described hydraulic functions
t~e control handle ~ay be also rotated forwardly or rearwardly to control
direction and speed of operation of the lift truck via certain control
circuits of FIG. 6 as above described. The overall control handle
operation and structure is extremely novel in the manner of mounting and
control of all functions of the lift truck except steering by means of
rotational movement of handle 62 to control direction and speed and linear
axial movement to control all hydraulic functions ;n either direction and
in any serial order selected by an operator.
The mount;ng and design of the control handle is such that it is
comfortable and easy for the operator to operate. The sl;ding linear
motion controlling all hydraulic functions requires no wrist motion so that
the travel and speed function will not be lnadvertently operated during
control of hydraulic functions. The operating control system requires two
hoses only and a three wire electrical cable in the upright which enhances
operator visibility.
It will be apparent to those skilled in the art that various changes in
the structure and relative arrangement of parts may be made without
necessarily departing from the scope of my invention as defined in the
claims appended.
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