Note: Descriptions are shown in the official language in which they were submitted.
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AN ERGONOME _ C CONTROL SYSTEM FOR
SWING REACH VEHICLE_
Field of the Invention
The invention relates to an advanced control
system for material handling vehicles containing
new and improved control features for combining
ease of operation with safety, and more
particularly to an ergonometric set of controls for
operating fork lift vehicles with greater comfort,
ease, efficiency and saf~ty.
BACKGROUND OF THE INVENTION
Anyone who has ever observed the operation of,
or who has actually operated a fork lift vehicle
will appreciate the complexity of the various
control levers for achieving the movement of the
vehicle and its subsystems, such as carriage, forXs
and mast. Even experienced material handling
operators will occasionally pull or depress the
wrong lever, when operating their vehicles.
While a rigorous training course is always
required before an operator is certified to operate
these vehicles, more complex vehicle controls
require more complex training. The more complex
the controls, the greater the possibility of
improper operation. Additionally, more complex
controls require increased focus over a long shift,
a situation that unfortunately lends itself to loss
of operator's attention. Loss of attention results
in fatigue that could lead to improper or hazardous
operation of the vehicle.
It is not uncommon for the fork lift operators
to complain that their hands, feet and/or back hurt
after a normal operating shift. The controls are
often uncomfortable to the hand. Some levers are
2 ~ ~ t''~
remotel~ located about the operator compartment,
and require an extended reach ~or access.
Obviously, there is wasted motion moving from one
lever to the next. Some typical controls that are
presently in use require extended push or pull
movements to actuate the desired vehicle movements.
All of these excessive operator movements and
inconveniences of control access cause operator
fatigue, cumulative trauma disorders such as carpal
10 tunnel syndrome, and operating inefficiencies. In
addition, these extraneous movements threaten safe
vehicle operation.
Some of the control levers are contrary to the
normal senses of the operator relative to the
15 motions of the operation. For example, fork
movement levers may require a push or a pull to
lift or lower the lifting mechanism. At times the
same lever may be used to actuate several functions
via a secondary select switch. Such actuating
20 devices can cause confusion and inefficiency.
~otions contrary to the normal senses not only make
the task of lParning to opera~e the material
handlin~ vehicle more difficult, but may also be an
underlying cause of confusion leading to improper
25 operation.
Many of the control levers now in use can be
confused, because they have the same shape, motion,
and actuation modality for different functions.
Levers disposed upon the same control panel are
30 often distinguishable only to the highly trained
operator.
In summary, there are many drawbacks with the
use of the current system of controls for material
handling vehicles. These disadvantages may be
35 summarized as follows:
~a) There are just too many inconveniently
placed control levers Eor e~ficient and convenient
operation of the material handling vehicle;
(b) Safe operation of these control levers is
not always clearly defined, and may be contrary to
the normal senses of the operator relative to the
motions of the operation;
(c) Present day control levers are usually
not designed with operator comfort in mind. The
control or actuating levers are. not designed to be
comfortable to the touch or grip of the operator;
(d) The complexity of the controls of a
material handling vehicle lead to inefficiencies of
operation. Often simultaneous operations cannot be
performed;
(e) Control levers require too much operator
effort to actuate the desired vehicle operation;
(f~ The operator must move from actuator to
actuator to effect different control functions;
~0 ' (g) Levers are often indistinguishable in
appearance and actuation, often leading to
confusion as to which lever is to be thrown to
effectuate a particular function; and
(h) Most of the present day controls are more
~5 mechanically actuatable, rather than electrically
actuatable.
The present invention seeks to overcome all of
the above drawbacks and disadvantages.
The current invention seeks to reduce expended
energies and motions by operators of fork lift
vehicles in actuating the vehicular con~,rols.
These measurements have resulted in a new control
ergonometry. Switching or selecting control
~unctions has been designed to be more electrically
and less mechanically actuatable.
2 ~8 '~ ~ c~ tJ
A new pair of control levers or handles has
been designed. The new handles are shaped -to
conform to the grip of the human hand, thus
providing operator comfort. Most of the control
function actuators have been designed and
integrated into these control handles, reducing the
time and enPrgy needed to reach, push or pull these
actuator controls. Most of the controls are at the
finger tips of the operator providing easy access.
Simultaneous functions can ~e accomplished easily.
Each of the finger tip controls has a
different shape, feel, and/or actuation movement,
so that each control actuator is easily
distinguished from its neighboring control
a~tuators~ Each function is easily selected, thus
eliminating confusion, and allowing the operator to
easily learn to operate the vehicle. This ease of
operation translates into operating efficiency.
These actuators require a minimum of motion
and/or energy to access and operate. This
additionally translates into operating efficiency.
The actuators have been designed to provide
tactile awareness. They conform to the natural,
intuitive motions and senses of the operator, and
to the functions that are being actuated. This
translates into operating safety.
The ergonometric control system of this
invention therefore provides controls that the
operator will find comfortable, easy to operate,
efficient and safe.
SUMMARY OF THE INVENTION
Xn accordance with the present invention,
there is provided an ergonometric control system
-for material handling vehicles, such as fork lift
trucks. The system comprises a pair of right and
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left control handles. The handles are disposed
about the operator compartment of the vehicle, and
are utilized to control the vehicle. The handles
conform to the respective right and left hand grips
of the operator. The handles provide operator
support throughout vehicle operation. As such,
this conformity to the hand grips provides
comfortable controls as well as ease of vehicle
operation. ~ach handle comprises a plurality of
closely spaced, easily accessed function actuators
that allow for simultaneous control of two or more
vehicular functions. All the actuators are
integrated into their respective handle~ such that
they are within finger tip reach of the operator's
hand. These actuators and handles each provide
intuitive sense control. That is, each handle and
actuator moves in the same sense as the function
for which it is designed. For example, when seated
or standing while facing the forks, the right
handle is thrust forward for forks first movement
and backward for tractor first movement of the fork
lift vehicle.
A lift/lower lever actuator on the top portion
of the right handle is positioned off-center, so
that the operator pushes upward or downward on this
lever to effectuate the respective lifting and
lowering of the main mast or auxiliary mast. A
horn push button is disposed adjacent the
lift/lower lever on the right handle. Below the
horn button is disposed a two-position, toggle-
type, automatic/manual select switch for selecting
manual steering or automatic (guide wire) control
of the vehicle. Still another push button disposed
adjacent the automatic/manual select switch
coordinates vehicle rotation and travel functions,
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On the top portion of the left handle is
located a fork rotate lever disposed off-center.
This fork rotate lever is pushed either to the
right (CW) or left (CCW) for actuating the rotation
of the ~orks either clockwise (CW) or counter-
clockwise (CCW), respectively. Below the fork
rotate lever is a push button for selecting the
auxiliary mast over the main mast. Actuating the
lift/lower lever causes the main mast to lift or
lower, and actuating the lift/lower lever while
depressing the mast select push button causes the
auxiliary mast to lift or lower. ~djacent the mast
select push button is an optional three-position
toggle~type selector switch for tilting the forks.
Next to this switch is a push button for overriding
the mast vertical travel limit.
The left control handle itself can be thrust
forward and backward to provide movement of the
auxiliary mast and forks to the left and to the
right, respectively.
Large movements are not necessary to actuate
or control the various function actuators, or to
move from one actuator to the other. In this
manner, the actuators are more electrically, rather
than mechanically actuatable.
Substantially all of the actuators are
physically and functionally distinct in how they
are accessed, so that they do not cause confusion
between the particular functions being controlled.
This in turn makes the control system easier to
learn and to operate.
BRIEF DESCRIPTION OF THE DRAWINGS
A complete understanding of the present
invention may be obtained by reference to the
accompanying drawings, when considered in
2 ~ 3
conjunction with the subsequent detailed
description, in which:
FIGURE 1 illustrates a perspective view of a
swing-reach type material handling vehicle
featurillg the ergonometric control system of this
invention, and a vehicle operator sitting at the
controls;
FIGURE 2 shows a perspective, front view of
the ergonometric control system and operator seat;
and
FIGURES 3a and 3B illustrate a back view of
the right and left control arms of the ergonometric
control system depicted in FIGURE 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Generally speaking, the invention features a
new ergonometric control system for a material
handling vehicle, such as a fork lift truck. The
control system of the inv~ntion is user friendly.
The controls have been designed to be comfortable
to the vehicle operator, provide easier access to
the function actuators, and allow for simultaneous
control of two or more vehicle functions.
For purposes o~ clarity and brevity, like
components and elements will bear the same
designation throughout the figures.
Now referring to FIGURE 1, a swing-reach truck
10 is shown, with an operator 9 sitting at the
ergonometric controls of this invention. The
ergonometric controls are part of an operator
compartment described in greater detail
hereinbelow. The swing-reach truck 10 is a typical
type of material handling vehicle that can benefit
from the ergonometric control system of this
invention. It is to be understood that this
vehicle is one of many vehicles that can utilize
the invention, and is displayed herein by way of
example
The swing-reach truck 10 comprises a pair of
forks 12 that are carried upon a rotatable frame 13
so that the forks 12 can rotate 180 from facing
le~t with respect to the seated operator 9 (as
shown) to facing right. The rotatable frame 13 is
rotatively connected to extension arm 14 via a
rotating shaft 15.
Extension arm 14 is vertically movable upon an
auxiliary mast 16 via a chain 19, which is carried
by a hydraulic cylinder 19a. Thus, the forks 12
are movable up and down (arrow 20).
Auxiliary mast 16 is horizontally movable
alona upper and lower racks 25 and 26,
respectivelyO In this way, the mast/fork assembly
can be transported from the seated operator's right
(as shown) to his left.
Moreover, forks 12 are extendable from
rotatable frame 13 on a scissor-like mechanism (not
shown). This extending action occurs automatically
at the end of the horizontal movement of mast 16
along racks 26 and 26, thus bridging the gap
between vehicle lo and storage racks, not shown.
The operator platform 18, carrying the
operator 9 and auxiliary mast assembly 16, is
likewise movable up and down (arrows 22) via a main
mast 21 via chains, not shown, which are carried by
hydraulic cylinders, not shown.
Referring to FIGURE 2, it will be observed
that the control arms 24 and 25 each carry
respective right and left control handles 30 and
31. Control arm 25 also carries a vehicle steering
knob 29, and control arm 24 also carries an
emergency power off (EPO) palm depress button 26.
On arm 24 there is mounted a control console
27 which includes a power key switch 27a, an
oparator display ~7b and a plurality of selector
switches 27c for work li.ghts and fans.
Referring to FIGIJRES 3a and 3b, the control
handles 30 and 31 are shown in an operating
position facing towards the forks. Ik will be
noted that the right control handle 30 is a mirror
image of the control handle 31. However, each
control arm, with its respective actuators
described hereinbelow, controls different
functions. The control handles 30 and 31 are
shaped to conform to the grip of the operator 9.
The respective contoured surfaces 40 and 41 conform
to the clenched hands of the operator, and provide
a comfortable grasp of the control handles 30 and
31, respectively. This is important, because these
handles can serve to support the operator 9 during
the operation and movement of the vehicle.
Control handle 30 controls the vehicle travel
direction and speed when it is rotationally
displaced about axis 35. Control handle 31
controls the horizontal displacement and speed of
auxiliary mast 16 along racks 25 and 26, including
the extension of the scissor-like mechanism, not
shown. Pushing control handle 31 moves auxiliary
mast 16 to the left, while pulling handle 31 moves
mast 16 to the right.
The right control handle 30 has a number of
distinctive actuators A, B, C and D, which
correspond to the actuators A', B', C' and D'
disposed on control handle 31. It will also be
- observed that each of the respective actuators A,
B, C, and D, or A', B', C' and D' on the right or
the left control arms 30 and 31, respectively, has
a difEerent shape, and actuates a control function
in a different way~ For example, actuator levers D
and D' each are disposed at the top portions 50 of
the contrctl arms. They are located in off-center
locations on top portions 50, necessitating that
the thumb of the hand must push upwardly or
downwardly (arrows 45 and ~6) upon these levers to
effectuate lever movement. Lever D controls the
lifting or lowering speed of the forks 12 upon main
mast 21, while lever D' controls the rotation
direction and speed of the forks with respect to
support arm 14.
The respective flat buttons A and A' control
the vehicle horn and the lift/lower selection of
the auxiliary mast 16 respectively, in the lift
mode. In operation, button A' is held depressed
while lever D is rotated in order to raise or lower
the auxiliary mast 16. If lever D is rotated
without depressing button A', the main mast 21 i5
controlled. These buttons must be depressed by the
thumb, rather than pushed or pulled, as required
for levers D and D', in order to actuate their
functions~
Selector switches B and B' respectively
control the manual/automatic vehicle travel mode
and the fork tilting positions. The
manual~automatic vehicle tra~el mode relates to
either drivar operated or guided vehicular control.
The three-position spring return-to-center selector
switch B' allows the forks 12 to tilt upwardly or
downwardly. Selector switch B is a two-position
rocker switch, and requires a rocking motion to
effect actuation of the desired function. These
switches B and B' can generally be actuated by the
middle fingers or thumb of the operator's hand.
Finally, the round cap button C, in
conjunction with left control handle 31, selects
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the coordination between rotation of forks 12 and
horizontal traverse of auxiliary mast 16 along
racks 25 and 26 in accordance with a preprogrammed
speed/displacement profile. Round cap button C' is
used, when lifting, to override the main mast
lift/limit switch, not shown. These round cap
buttons C and C~ can be depressed by the operator's
thumb in order to actuate their functions.
Thus it will be evident that all of the
switches, and the control handles themselves, have
different functions, different shapes and feel, and
different modes of actuation. In this manner, it
is unlikely that an operator will confuse the
vehicle function which he desires to invoke with
the actuation of these control elements.
It is also to be noted that each switch,
button, lever, etc., including the control handles,
is designed to move in a direction that is
conceived to be functionally proper by the
operator. This tactile awareness also assists in
actuating the various functions properly, and
avoids costly errors.
Also, it should be o~served that since all the
control elements are closely spaced and can be
actuated by either hand, it is possible to invoke a
plurality (at least two) of functions
simultaneously.
The present invention, by placing all the
control functions within finger-tip control, not
only eliminates th~ previous need to move between
control levers, but also eliminates large throw
distances for actuation. All of the advantages of
the invention provide a reduction in energy and
effort. At the end of the work shift, the operator
will be less tired and fatigued. Also, as
aforementioned, the control handles 30 and 31 have
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been des.igned to fit comfortably within the
operator's hand, in order to reduce fatigue and
make the work more enjoyable.
Since other modifications and changes varied
to fit particular operating requirements and
environments will be apparent to those skilled in
the art, the invention is not considered limited to
the example chosen for purposes o~ disclosure, and
covers all changes and modifications which do not
constitute departures from the true spirit and
scope of this invention.
Having thus described the current invention,
what is desired to be protected by Letters Patent
is presented by the subsequently appended claims.
What i5 claimed is:
