Electricity: circuit makers and breakers – Combined with or actuated by connector coupling – Multiple circuit control – selective
Reexamination Certificate
1998-12-21
2001-01-30
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Combined with or actuated by connector coupling
Multiple circuit control, selective
C200S01700A, C200S573000
Reexamination Certificate
active
06180898
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an emergency stop switch mechanism for a robot and a teaching operation panel with such mechanism, and more particularly to an emergency stop switch mechanism capable of taking an emergency stop position not only when an external operation force is not applied but also when a strong external operation force is applied and a teaching operation panel provided with the same mechanism.
BACKGROUND ART
As an emergency switch mechanism for stopping a robot in emergency, there is known what is called a deadman switch mechanism. Usually, the deadman switch mechanism is provided at one place or a plurality of places on a teaching operation panel connected to a robot controller. In normal operation, an operator holds the teaching operation panel and operates the robot while applying an external operation force (pressing, gripping, etc.) to an external operation force applicator (lever, button, knob, handle, etc.) of the deadman switch.
Most conventional deadman switches use a two-position type switch mechanism. Specifically, the two-position type deadman switch mechanism is an enable/disable switch mechanism having two positions of an applicator position at which the robot motion is disabled and an applicator position at which the robot motion is allowed.
FIGS. 15
a
and
15
b
show an outline of a two-position type switch mechanism used for a conventional deadman switch;
FIG. 15
a
shows a state in which an external operation force is not applied, and
FIG. 15
b
shows a state in which an external operation force is applied.
Referring to
FIGS. 15
a
and
15
b
, for the external operation force applicator of the deadman switch mechanism, a main lever L
1
provided exposedly on a operation surface of a teaching operation panel and an ancillary lever L
2
pushed by a plunger PL provided to the main lever L
1
are pivotally supported by an axis AX
1
with an elastic biasing force S
1
indicated by the arrow mark.
When starting the robot operation, the operator pushes down the main lever L
1
from the OFF state shown in
FIG. 15
a
with a force overcoming the elastic biasing force S
1
. Accordingly, the ancillary lever L
2
is pushed down and a movable contact element ME provided on a contact mechanism section CM is moved to the ON position, so that the ON state shown in
FIG. 15
b
is established. In this ON state, the robot motion is permitted. The movable contact element ME normally has the OFF position; it is biased toward the OFF position (position projecting upward) by a publicly known proper biasing mechanism (not shown) and a stopper mechanism.
If an emergency stop of robot becomes necessary during the operation of robot, the pushing pressure of the main lever L
1
is released from the ON state shown in
FIG. 15
b
. Then, the main and ancillary levers L
1
and L
2
are returned to a neutral position (or a position regulated by a stopper) by the elastic biasing force S
1
, so that the state shown in
FIG. 15
a
is established. In this state, the robot motion is prohibited.
When the operator feels a necessity for the emergency stop of robot, he/she must stop the application of external operation force of the deadman switch mechanism by an action such that his/her finger is set free from the lever (operation external applicator) or such that his/her hold of the teaching operation panel itself is released.
However, considering the operator's psychology, such an action can not always be taken reflectively when a state of emergency is created. In particular, the action such that the operator's hold of the teaching operation panel is released is accompanied by a psychological resistance, which delays the emergency stop of robot, whereby there may be a possibility of bringing about a dangerous situation.
For this reason, in addition to the conventional two-position switch mechanism of OFF (external operation force is not applied; robot motion is prohibited) and ON (external operation force is applied; robot motion is permitted), there has been proposed a three-position switch mechanism of OFF (external operation force is not applied; robot motion is prohibited), ON (external operation force is applied; robot motion is permitted), and OFF (external operation force is applied; robot motion is prohibited) such that the robot can be stopped in emergency by pressing a switch button with an especially strong force.
However, the conventionally proposed three-position deadman switch mechanism has disadvantages that the mechanism is large and complex and that it is difficult to apply an external force so that two states, a state in which the robot motion is prohibited and a state in which the robot motion is permitted, are distinguished definitely from each other while the external operation force is applied.
DISCLOSURE OF INVENTION
An object of the present invention is to provide a three-position type emergency stop switch mechanism for a robot, which is simple in construction and is capable of clearly specifying a difference between a robot motion prohibiting state (OFF position) and a robot motion permitting state (ON position) by the strength of applied external operation force. Also, another object of the present invention is to provide a teaching operation panel for a robot, which is provided with the above emergency stop switch mechanism, to thereby improve the operability of the teaching operation panel and secure the operator's safety.
The emergency stop mechanism for a robot of the present invention comprises: switch means which takes an ON position for permitting a robot motion and an OFF position for stopping the robot motion; an operative member which acts on the switch means for switching the ON and OFF positions; an external-operation-force receiving member elastically supported with a first biasing force, for receiving an external operation force; and connecting means for elastically connecting the operative member to the external-operation-force receiving member with a second biasing force which is larger than the first biasing force.
When a normal operation force larger than the first biasing force but not larger than the second biasing force is applied to the external-operation-force receiving member, the connecting means substantially maintains the relative position of the external-operation-force receiving member and the operative member so that the external operation force acts on the switch means to be switched from the OFF position to the ON position. When a special operation force exceeding the second biasing force is applied to the external operation force receiving member, the connecting means changes the relative position of the external-operation-force receiving member and the operative member so that the external operation force does not act on the switch means to be switched from the ON position to the OFF position.
The connecting means which meets the above condition can be embodied in various modes by using various rotational members (lever, etc.), connecting members (link, etc.) and elastic members (coil spring, extension/compression spring, etc.) which are provided in association with the external-operation-force receiving member.
In any mode, the following condition is met. When the normal external operation force is applied to the external-operation-force receiving member (lever, etc.), the connecting means substantially maintains the relative position of the external-operation-force receiving member and the operative member, so that the switch means is switched from the OFF position to the ON position. When a strong external operation force exceeding the normal external operation force is applied to the external-operation-force receiving member, the relative position of the external-operation-force receiving member and the operative member is changed, so that the switch means is switched from the ON position to the OFF position.
The emergency stop switch mechanism can be arranged at an appropriate position on the teaching operation panel. In particular, the switch mechanism should preferably be
Abe Ken-ichiro
Terada Akihiro
Yasumura Mitsuhiro
Fanuc Ltd.
Friedhofer Michael
Staas & Halsey , LLP
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