Electricity: electrical systems and devices – Control circuits for electromagnetic devices – Systems for magnetizing – demagnetizing – or controlling the...
Reexamination Certificate
2001-12-04
2003-10-21
Tso, Edward H. (Department: 2838)
Electricity: electrical systems and devices
Control circuits for electromagnetic devices
Systems for magnetizing, demagnetizing, or controlling the...
Reexamination Certificate
active
06636410
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATION
This application claims all benefits accruing under Paris Convention from the Japanese Patent Application No. 2000-370587, filed on Dec. 5, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a relay apparatus, with reliability, which is suitable for, e.g., an application in which load as a target is driven only upon completely satisfying a plurality of input conditions for safety confirmation, etc. More particularly, the present invention relates to a relay apparatus, with a safety function by which the relay apparatus is completely operated even in a failure mode of the welding and fixing of a relay contact and an external input contact, and the failure mode is detected and is prevented at the next driving operation of the relay apparatus.
2. Description of the Related Art
The above-mentioned relay apparatus with the safety function shown in a circuit diagram in
FIG. 6
is well-known. As shown in
FIG. 6
, the relay apparatus with the safety function comprises: two input terminals T
11
and T
12
and two input terminals T
21
and T
22
, to which external non-voltage contacts are connected; two input corresponding electromagnetic relays provided corresponding to the number of the input terminals (hereinafter, one input corresponding electromagnetic relay is referred to as a first electromagnetic relay, and the other input corresponding electromagnetic relay is referred to as a second electromagnetic relay); a self-maintaining set relay for outputting a self-maintenance setting signal to the first and second electromagnetic relays; and output terminals OUT
1
and OUT
2
to be connected to loads.
A first switch S
1
and a second switch S
2
connected to the input terminals T
11
and T
12
and the input terminals T
21
and T
22
comprise contacts such as limit switches comprising external non-voltage contacts. A coil K
1
of the first electromagnetic relay functions as an input corresponding electromagnetic relay, a coil K
2
of the second electromagnetic relay functions as an input corresponding electromagnetic relay, and a coil K
3
of a third electromagnetic relay functions as a self-maintaining relay.
The coil K
1
, a constant-opened contact K
1
-
2
for output, a constant-opened contact K
1
-
1
for control, and a constant-closed contact K
1
-
3
for control are provided for the first electromagnetic relay which functions as the input corresponding electromagnetic relay. Also, the coil K
2
, a constant-opened contact K
2
-
2
for output, a constant-opened contact K
2
-
1
for control, and a constant-closed contact K
2
-
3
for control are provided for the second electromagnetic relay which functions as the input corresponding electromagnetic relay. Further, constant-opened contacts K
3
-
1
and K
3
-
2
for outputting a self-maintenance setting signal to the first electromagnetic relay and the second electromagnetic relay and a constant-closed contact K
3
-
3
for output are provided for the third electromagnetic relay which functions as the self-maintaining relay.
The first switch S
1
connected to the input terminals T
11
and T
12
, as the external non-voltage contact, the constant-opened contact K
1
-
1
for control of the first electromagnetic relay, as the input corresponding electromagnetic relay assigned to the first switch S
1
, and the coil K
1
of the first electromagnetic relay are serially connected among terminals of a power source E. As a consequence, a self-maintaining circuit of the first electromagnetic relay is formed in which the first switch S
1
is a contact for reset and the constant-opened contact K
1
-
1
for control is a contact for maintenance.
Also, the second switch S
2
connected to the input terminals T
21
and T
22
, as the external non-voltage contact, the constant-opened contact K
2
-
1
for control of the second electromagnetic relay, as the input corresponding electromagnetic relay assigned to the second switch S
2
, and the coil K
2
of the second electromagnetic relay are serially connected among terminals of the power source E. As a consequence, a self-maintaining circuit of the second electromagnetic relay is formed in which the second switch S
2
is a contact for reset and the constant-opened contact K
2
-
1
for control is a contact for maintenance.
The constant-closed contacts K
1
-
3
and K
2
-
3
for control of the first and second electromagnetic relays as the input corresponding electromagnetic relays are serially connected and are inserted to a closed circuit via the power source E. The coil (input circuit) K
3
of the third electromagnetic relay comprising the self-maintaining relay is further inserted to the closed circuit. The above-mentioned switch for set in the self-maintenance comprises the constant-opened contacts (output circuits) K
3
-
1
and K
3
-
2
for control of the third electromagnetic relay comprising the self-maintaining relay.
Further, the constant-opened contacts K
1
-
2
and K
2
-
2
of the first and second electromagnetic relays as the input corresponding electromagnetic relays and the constant-closed contacts K
3
-
3
for output of the third electromagnetic relay as the self-maintaining relay are serially connected between the output terminals OUT
1
and OUT
2
. As a consequence, a closed circuit via a load (not shown) is constituted.
Next, an operation will be described. When all of the first electromagnetic relay, the second electromagnetic relay, and the third electromagnetic relay are normal, only if both the first switch S
1
and the second switch S
2
are closed, an interval between the output terminal OUT
1
and the output terminal OUT
2
is opened. In other words, if one of the first switch S
1
and the second switch S
2
is opened, the interval between the output terminal OUT
1
and the output terminal OUT
2
is opened.
If a failure of contact welding (fixing) is caused in any of the first electromagnetic relay, the second electromagnetic relay, and the third electromagnetic relay, even if the failed electromagnetic relay is operated, one of the first switch S
1
and the second switch S
2
is opened. The interval between the output terminal OUT
1
and the output terminal OUT
2
is normally opened. Further, when a failure of devices is caused in the relay apparatus with the safety function, even if both the first switch S
1
and the second switch S
2
are thereafter closed, the interval between the output terminal OUT
1
and the output terminal OUT
2
is not closed. That is, if a failure is caused at the coil or the contact of the incorporated relay, the safety function is automatically operated.
However, the conventional relay apparatus needs a single electromagnetic relay as a self-maintaining relay as well as the two electromagnetic relays as the input corresponding electromagnetic relays and, therefore, there is a problem in that the overall apparatus is necessarily increased in scale.
SUMMARY OF THE INVENTION
The present invention is devised in the consideration of the above-mentioned problem and it is an object of the present invention to provide a relay apparatus, with a safety function, which is miniaturized.
To accomplish the above-mentioned object, according to the present invention, there is provided a relay apparatus comprising: at least one self-maintaining relay and another self-maintaining relay which are provided corresponding to input terminals; a dielectric which charges and discharges electrical energy; energizing means which energizes the dielectric and charges the electrical energy to the dielectric; one starting means which outputs a start signal to an input side of the one self-maintaining relay and enables a self-maintaining circuit of the one self-maintaining relay to be formed; another starting means which is operated by a self-maintaining operation of the one self-maintaining relay, outputs the electrical energy charged to the dielectric as a start signal, and enables a self-maintaining circuit of the other self-maintaining relay to be formed; and output means which is operated by the sel
Ide Takahiro
Nagashima Yoshimasa
Foley & Lardner
Omron Corporation
Tibbits Pia
Tso Edward H.
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