This invention relates to a portable controller for robot, which
carries out operation of instruction to an industrial robot.
Hitherto, when carrying out operation of instruction to an industrial
robot, an operator grips or grasps a portable controller by one hand or both hands
to push a key or keys on the controller by thumbs of the both hands or finger of
hand by which the controller is not gripped (held). In the portable controller,
so called a deadman (dead-man's type) switch such that it is operative for a time
period during which the controller is touched by hand, and it is stopped when hand
is away from the controller is assembled in view of safety in the operation of
the robot. As a portable controller of this type, there is disclosed a portable
controller in which, in order that respective finger tips come into contact with
keys of the controller at the same time when the operator grips or holds the portable
controller from the lateral direction, a pressing plate of the deadman switch is
disposed at the back side of the portable controller, and an inclined surface is
provided at the controller back side edge portion with which hand of the operator
comes into contact (e.g., Japanese Patent Application Laid Open No. 207580/1988).
Moreover, there is disclosed a portable controller in which a finger
fitting portion having a shape such that finger is fitted is provided on the back
side of the portable controller in order that an operator dose not become tired
even if he grips or holds it for a long time (e.g., Japanese Utility Model Application
Laid Open No. 70893/1988).
Since the work for giving instruction to the robot is carried out
near the robot body, it is necessary to imergently or immediately stop the robot
for the purpose of protection of the operator when the robot runs away for any
reason. As a momentary operation when the robot runs away, there are instances
where the operator allows his hand to be away from the portable controller, or
there are instances where he tightly grips or grasps the portable controller.
However, in the constitution in which the deadman switch which is
stopped when operator's hand is away from the controller is assembled as described
above, there was the drawback that when operator tightly grips the controller,
its objective is not attained although there is the effect when operator's hand
is away from the portable controller.
Disclosure of the Invention
An object of this invention is to provide a portable controller for
robot of the fail-safe type in which the switch is turned OFF both when operator
allows his hand to be away from the portable controller and when he tightly grips
or grasps the portable controller at the time of runaway of the robot.
To solve the above-mentioned problems, this invention is directed
to a portable controller in which a finger fitting portion is provided at least
at one side edge of the back plate of a box-shaped casing (housing), and a deadman
switch which is turned OFF when no pressure is applied to the finger fitting portion,
is turned ON by pressing force (pressure) when the finger fitting portion is gripped,
and is turned OFF when the finger fitting portion is pressed by pressing force
(pressure) greater than pressing force (pressure) when the finger fitting portion
is gripped is provided at the finger fitting portion, the deadman switch comprises
a pressing plate which can be inserted into a recessed portion provided within
the finger fitting portion and can be withdrawn therefrom, a shaft having a shape
of offset provided at the pressing plate, a dog plate fitted over the offset portion
of the shaft and having a plurality of holes at the circumferential edge of the
shaft, a plurality of bosses adapted to be inserted into the plurality of holes
of the dog plate, a spacer in contact with the respective top portions of the
bosses, and fitted over the shaft, a spring provided at the shaft outer circumferential
portion so that one end is supported in the state pressed onto a fixed portion
provided at the shaft front end side and the other end presses the spacer, and
a three point type limit switch attached on the back plate and such that when
the dog is engaged with the dog plate so that the limit switch is in free state,
it turned OFF, when the dog plate slightly presses the dog, it is turned ON, and
when the dog plate comes into contact with the spacer to further deeply press the
dog against spring force of the spring, it is turned OFF.
In the case where the operator tightly grips the finger fitting portion,
the pressing plate is caused to be pressed into the recessed portion against spring
force (pressure) of the spring, thus making it possible to place the limit switch
in the OFF state of the third point through the shaft and the dog plate.
As described above, in accordance with this invention, since the
portable controller is securely placed in OFF state even if operator tightly grips
the portable controller in the panic state based on runaway, etc. of robot, an
extremely safety portable controller for robot of the fail-safe type can be advantageously
In addition, since the three point type limit switch is used, even
if operator tightly grips the portable controller and then allows the hand to be
away therefrom, there is no possibility that the industrial robot is brought into
ON state even momentarily for a time period during which the limit switch of the
portable controller is returned to the original position. Thus, higher safetey
is advantagerously provided.
Brief Description of the Drawings
FIG. 1 is a view showing an embodiment of this invention, FIG. 2
is a plan view of FIG. 1, and FIG. 3 is an essential part side cross sectional
view showing the operation of the embodiment of this invention, wherein FIG. 3(a)
shows the state of the first point where the three point type limit switch is not
pushed, FIG. 3(b) shows the state of the second point where the three point type
limit switch is lightly or slightly pushed, and FIG. 3(c) shows the state of the
third point where the three point type limit switch is strongly or deeply pushed.
Best Mode for Carrying Out Invention
An embodiment of this invention will now be described.
FIG. 1 is an A-A cross sectional view shown in FIG. 2 of the embodiment
of this invention, and FIG. 2 is a plan view, wherein a portable controller 1 includes
a keyboard section 21 and a display section 22, and a box-shaped casing is composed
of a face plate 2 for covering an operation circuit section 23 and a back plate
3 surrounding the operation circuit section 23 along with the face plate 2. At
the both side edges of the back plate 3, there are provided finger fitting portions
31 having curve shape projected toward the back side so that four fingers except
for thumb are fitted in the state where no force is applied when operator grips
A recessed portion 32 is provided at the finger fitting portion 31
of the left side, and a deadman switch 4 is mounted on the bottom portion thereof.
At the opening portion of the recessed portion 32, there is provided a pressing
plate 5 having substantially the same curved surface as the finger fitting portion
31 and admitted into the recessed portion 32 so that it is subjected to insertion/withdrawal,
whereby when operator grips the finger fitting portion 31, the pressing plate 5
is pressed so that it is admitted into the recessed portion 32 to allow the deadman
switch 4 to be operative.
A strap 6 is provided at the side surface of the face plate 2 to
prevent that the portable controller 1 is fallen carelessly.
The detailed structure of the deadman switch 4 is shown in FIG. 3.
A shaft 7 passed through a penetration hole 33 provided at the bottom
portion of the recessed portion 32 is provided, and an offset portion 71 is provided
at the shaft 7. Projected bosses 34 are provided, e.g., at four portions at the
circumferential edge of the penetration hole 33. A dog plate 6 fitted over the
shaft 7 and having holes greater than the boss 34 at the same four positions as
those of the bosses 34 is in contact with the offset portion 71. A spacer 9 fitted
over the shaft 7 is in contact with the top portion of the boss 34 and a spring
8 is provided between the spacer 9 and a collar portion 101 of a spring holding
portion 10, wherein the lower end of the spring holding portion 10 is fixed on
the back plate 3. The pressing plate 5 is fixed by screws to the end portion protruded
toward the outside of the back plate 3 of the shaft 7.
At the back plate 3, two limit switches 41, 42 are provided in such
a manner that they are opposite to the dog plate. The two limit switches 41, 42
perform the same action (function). If, e.g., limit switch 41 is failed (out of
order), since the limit switch 42 is operating, there is no possibility that the
function is lost. These limit switches 41, 42 are three point type limit switch.
They are set so that in the free state, they are turned OFF, when dogs 41a, 42a
are slightly pressed, they are turned ON, and when dogs 41a, 42a are further deeply
pressed, they are turned OFF. In addition, the limit switches 41, 42 are set so
that when these dogs 41a, 42a are returned to the original state from the state
where they are deeply depressed, they are returned directly to the initial OFF
state without routing the ON state.
In the state where operator does not grip the portable controller
1, the dog plate 6 is thrust or forced to the back plate 3 by pressure of springs
provided within the limit switches 41, 42. As a matter of course, the limit switches
41, 42 are in OFF state.
In the case where operator grips the portable controller 1 to operate
it, he grips the finger fitting portion 31 along with the pressing plate 5. At
this time, as shown in FIG. 3(b), the pressing plate 5 is inserted into the recessed
portion 32 so that the dog plate 6 presses the dogs 41a, 42a to slightly push these
dogs 41a, 42a into the limit switches 41, 42. In this state, the dog plate 6 operates
the limit switches 41, 42, thus placing the operation circuit in the ON state where
operation of instruction, etc. can be made.
In the case where any necessity to urgently stop the operation of
the robot takes place by runaway thereof, so operator allows his finger (hand)
to be instantaneously or momemtarily away from the finger fitting portion 31, the
shaft 7 and the pressing plate 5 are pushed down through the dog plate 6 and the
offset portion 71 of the shaft 7 by spring pressure of spring (not shown) within
the limit switches 41, 42. Thus, the limit switches are returned to the OFF state
shown in FIG. 3(a).
Alternatively, in the case where operator instantaneously tightly
grips the finger fitting portions 31 along with the pressing plate by runaway,
etc. of robot, the pressing plate 5 is pushed into the recessed portion 32 against
spring pressure of spring 8 from the state of FIG. 3(b) to allow the dog plate
6 to compress the spring 8 through the spacer 9 as shown in FIG. 3(c) to allow
the dog plate 6 to operate the limit switches 41, 42 to cause them in the OFF state
of the third point. Further, when operator allows his finger to be away from the
finger fitting portion 31 from the above state, the limit switches 41, 42 are
returned to the original state while maintaining OFF state.
While the deadman switch 4 is provided at the finger fitting portion
of the left side, such deadman switch 4 may be provided at the finger fitting portion
of the right side for left handed operator, or those switches may be provided at
the both sides.
This invention can be utilized, when applied to a portable controller
for robot which carries out operation of instruction to industrial robot, in the
field for manufacturing and providing portable controllers for robot of extremely