Technical Field
The present invention relates to a time switch.
Background Art
Conventionally, there has been proposed a time switch
for performing a timer control on a control target load
pursuant to a predetermined time schedule (see, e.g., Patent
Document 1).
The time switch disclosed in Patent Document 1 is
installed in a facility such as a general house, an office
or a school. As shown in Fig. 8, the time switch is
connected, when in use, to a two-wire signal line Ls of a
remote monitoring and control system.
The remote monitoring and control system having a
configuration shown in Fig. 8 includes a time switch 71 for
performing the timer control on a corresponding load (an
illumination load) pursuant to a predetermined time
schedule, a remote control wiring device 73 for controlling
a relay 72 that switches on and off the supply of an
electric current to the load, and a plurality of (three, in
the illustrated example) operation switch wiring devices 74
to 7 6 for individually monitoring operation states of
operation buttons 74a to 7 6a. A brightness sensor 77 is
connected to the time switch 71.

The time switch 71 includes a program storage unit
(not shown) for storing the aforementioned time schedule.
An individual address allotted to the relay 72 to which a
control target load is connected, is stored in the program
storage unit together with the time schedule.
The remote control wiring device 73 includes a master
device (control master device) 73a provided with relays 72
for eight circuits and slave devices (control slave
devices) 73b each provided with relays 72 for four circuits.
The remote monitoring and control system having the
configuration shown in Fig. 8 includes a plurality of
control slave devices 73b. The control master device 73a,
the control slave devices 73b, the operation switch wiring
devices 74 to 7 6 and the time switch 71 are connected to the
signal line Ls.
In recent years, there has been proposed a relay-
mounted time switch for controlling a connected load at a
predetermined time (see, e.g., Patent Document 2).
The time switch disclosed in Patent Document 2
includes a control unit having a microcomputer, a power
supply unit for supplying a driving power, and an output
unit for, in response to an on/off command supplied from the
control unit, switching on and off the supply of a power to
a load connected through a pair of load connecting
terminals. The time switch includes a setting-purpose
switch unit for use in setting a program for controlling the

load at a desired time.
The output unit includes a drive circuit for
generating a drive signal in response to the on/off command
supplied from the control unit ' and a relay whose contact
points are opened and closed pursuant to the drive signal.
The load is connected to a commercial power supply via the
contact points of the relay.
[Patent Document 1] Japanese Patent Application
Publication No. 2007-251671
[Patent Document 2] Japanese Patent Application
Publication No. 2009-54385
In the time switch 71 of the remote monitoring and
control system having the configuration shown in Fig. 8, the
control master device 73a and the control slave devices 73b
are individually controlled to thereby perform the timer
control of the loads connected to the respective relays 72
of the control master device 73a and the control slave
devices 73b. In the time switch 71, it is therefore
necessary to perform a task of setting the individual
addresses allotted to the respective relays 72.
The time switch disclosed in Patent Document 2 is a
time switch having a single relay. For that reason, if one
wishes to control a plurality of loads, there is a need to
use a time switch with a plurality of (e.g., two or four)
relays or to use a multiple number of the time switches
disclosed in Patent Document 2.

In the time switch with a plurality of relays, for
example, if three loads are controlled by using a time
switch with four relays, one of the relays is left unused.
That is, the number of the relays is not equal to the number
of the control target loads. Thus, it is sometimes the case
that one of the relays becomes useless.
In case of using a multiple number of the time
switches disclosed in Patent Document 2, for the purpose of
controlling a plurality of loads at the same time, the
program for controlling the loads at a desired time needs to
be set by using the setting-purpose switch unit on each of
the time switches.
Summary of the Invention
In view of the above, the present invention provides a
time switch capable of providing a required number of relays
accurately corresponding to the number of loads as control
targets and capable of facilitating a setting task for
enabling a plurality of loads to be controlled at a same
time.
In accordance with an aspect of the present invention,
there is provided a time switch, including: a master device
including a time setting unit for setting a time and a first
relay arranged in a power supply path extending to a first
load, the master device having a function of controlling the

first relay at the time set by the time setting unit; and at
least one slave device including a second relay arranged in
a power supply path extending to a second load, wherein the
second relay is configured to close or open a contact point
of the second relay in synchronization with a closing or
opening operation of a contact point of the first relay.
The master device may include a first connector unit
provided with a first signal output terminal, through which
a synchronization signal is outputted, to synchronize the
closing or opening operation of the contact point of the
second relay with the closing or opening operation of the
contact point of the first relay, and the slave device may
include a second connector unit provided with a signal input
terminal through which the synchronization signal is
inputted and detachably connected to the first connector
unit, and a third connector unit provided with a second
signal output terminal, the second signal output terminal
being connected to the signal input terminal as an extended
connection. Further, the second connector unit of the slave
device may have a shape which is detachably connectable to
the third connector unit of another slave device.
Preferably, the slave device is supplied with an
electric power from the master device.
Each of the first connector unit and the third
connector unit may have a recess portion into which the
second connector unit having a protrusion portion is

detachably inserted, and a cover may be provided to open and
close an insertion hole of the recess portion.
The slave device may further include an operation
setting unit capable of setting the closing or opening
operation of the contact point of the second relay
regardless of the closing or opening operation of the
contact point of the first relay.
Effects of the Invention
With the time switch of the present invention, it is
possible to provide a required number of relays accurately
corresponding to the number of loads as control targets. It
is also possible to facilitate a setting task for enabling a
plurality of loads to be controlled at the same time.
Brief Description of the Drawings
The objects and features of the present invention will
become more apparent from the detailed description of
preferred embodiments given in conjunction with the
accompanying drawings.
Fig. 1 is a schematic configuration view of a time
switch in accordance with a first embodiment of the present
invention.
Fig. 2 is a circuit block diagram of a master device

of the time switch of the first embodiment.
Fig. 3 is a circuit block diagram of a slave device of
the time switch of the first embodiment.
Fig. 4 is a schematic configuration view of a time
switch in accordance with a second embodiment of the present
invention.
Fig. 5 is a schematic perspective view showing a
second connector unit of a slave device employed in the time
switch of the second embodiment.
Fig. 6A is a schematic perspective view showing a
first connector unit of a master device employed in the time
switch of the second embodiment, and Fig. 6B is a schematic
enlarged view showing a cover thereof.
Fig. 7 is a schematic configuration view of a time
switch in accordance with a third embodiment of the present
invention.
Fig. 8 is a system configuration view of a remote
monitoring and control system employing a conventional time
switch.
Detailed Description of the Preferred Embodiments
Hereinafter, embodiments of the present invention will
be described in more detail with reference to accompanying
drawings which form a part hereof. Throughout the
specification and the drawings, identical or similar parts

will be designated by like reference symbols with no
duplicate description made thereon.
(First Embodiment)
A time switch in accordance with a first embodiment of
the present invention will now be described with reference
to Figs. 1 through 3.
The time switch of the present embodiment is a time
switch for timer-controlling loads as control targets (e.g.,
an illumination device, an air conditioner, a ventilating
fan, and so forth) at a predetermined time. The time switch
of the present embodiment includes: a master device 10
provided with a time setting unit 11 for setting the
predetermined time and a first relay 5a arranged in a power
feeding path extending from a commercial power supply AC to
a load LI; and at least one slave device 20 provided with a
second relay 25a arranged in a power feeding path extending
from the commercial power supply AC to a load L2. In the
time switch of the present embodiment, there is provided a
plurality of slave devices 20. The master device 10 has a
function of controlling the first relay 5a at a time set by
the time setting unit 11 (hereinafter, referred to as
"preset time").
As shown in Fig. 2, the master device 10 of the time
switch in accordance with the present embodiment includes a
control unit 1 having, e.g., a microcomputer, a power supply
unit 2 electrically connected to the commercial power supply

AC via a pair of power supply terminals 19, and a first
output unit 5 provided with the aforementioned first relay
5a.
The control unit 1 includes a clock unit 7 for
measuring the current time based on clock signals outputted
from a clock oscillator unit 16 and a storage unit 6 that
stores a time schedule for controlling the load L1 at the
preset time. An oscillation unit 18 for outputting system
clock signals to operate the control unit 1 is also
connected to the control unit 1. In the time switch of the
present embodiment, the preset time previously set by the
time setting unit 11 is stored as a time schedule in the
storage unit 6.
When the current time measured by the clock unit 7
coincides with the preset time previously set by the time
setting unit 11, the control unit 1 outputs a control signal
S1 to control the first output unit 5.
The power supply unit 2 includes a step-down circuit
2a for stepping down an alternating current (AC) voltage
inputted from the commercial power supply AC through the
power supply terminals 19 and a direct current (DC)
conversion circuit 2b for converting the AC voltage stepped
down by the step-down circuit 2a to a direct current (DC)
voltage. The power supply unit 2 outputs the DC voltage
from the DC conversion circuit 2b to the control unit 1 and
the first output unit 5.

The master device 10 further includes an outage
detecting unit 4 for detecting a power outage of the
commercial power supply AC based on a decrease in the output
voltage from the power supply unit 2, and an outage-
compensating power supply unit 3 for outputting a DC voltage
to the control unit 1 on the occasion of the power outage of
the commercial power supply AC. In the time switch of the
present embodiment, therefore, the clock unit 7 of the
control unit 1 can maintain a clock function because the DC
voltage is outputted from the outage-compensating power
supply unit 3 to the control unit 1 on the occasion of the
power outage of the commercial power supply AC. The outage-
compensating power supply unit 3 may include, e.g., a
battery.
The first output unit 5 includes the aforementioned
first relay 5a and a drive circuit 5b for driving the first
relay 5a pursuant to the control signal S1 outputted from
the control unit 1. The first relay 5a includes a contact
point 5ab having a contact point c including contact points
a and b. In the present embodiment, the contact point a of
the contact point 5ab is arranged in the power feeding path
extending from the commercial power supply AC to the load
L1. In the time switch of the present embodiment, the
contact point 5ab of the first relay 5a has a contact
voltage. Alternatively, the contact point 5ab may be a
voltage-free contact point.

In the time switch of the present embodiment, the load
L1 is electrically connected to two load connecting
terminals 21a and 21b out of three load connecting terminals
21a, 21b and 21c. Two load connecting terminals 21a and 21b
out of three load connecting terminals 21a, 21b and 21c are
electrically connected to the contact point a of the contact
point 5ab of the first relay 5a. Two load connecting
terminals 21a and 21c out of three load connecting terminals
21a, 21b and 21c are electrically connected to the contact
point b of the contact point 5ab of the first relay 5a. In
the time switch of the present embodiment, the closing or
opening operation of the contact point 5ab of the first
relay 5a will be described as the closing or opening
operation of the contact point a of the contact point 5ab.
The contact point 5ab of the first relay 5a will be
described as a contact point with a contact voltage.
When the current time measured by the clock unit 7
coincides with the preset time previously set by the time
setting unit 11, the control unit 1 generates a
synchronization signal for synchronizing the closing or
opening operations of the contact points 25ab of the second
relays 25a of the respective slave devices 20 to the closing
or opening operation of the contact point 5ab of the first
relay 5a.
The master device 10 further includes a
synchronization signal transmitting unit 8 for transmitting

the synchronization signal generated by the control unit 1
to the slave devices 20 through a two-wire signal line Ls,
the aforementioned time setting unit 11 and a day setting
unit 12 for setting day of the week.
The synchronization signal transmitting unit 8 is
electrically connected to the signal line Ls through a pair
of first signal output terminals 22 and 22.
As a user operates a circular operation unit 17, the
time setting unit 11 sets a time at which the load L1
connected to a pair of load connecting terminals 21a and 21b
is turned on or off. While the time setting unit 11 is
configured, in the time switch of the present embodiment, to
set the on/off time of the load L1 in accordance with the
operation of the circular operation unit 17, the present
invention is not limited thereto. For example, the time
setting unit 11 may be configured to set the on/off time of
the load L1 in accordance with the operation of a push-type
operation unit. In this case, it is preferred that the time
switch of the present embodiment includes a display unit
having, e.g., a liquid crystal monitor.
The day setting unit 12 is designed to set the day of
the preset time previously set by the time setting unit 11.
For example, it is possible to set a time schedule such that
the load L1 is turned on at 8:00, a.m., every Monday.
The master device 10 further includes a first
operation setting unit 13 for setting one of an automatic

operation, a continuous turning-on operation, a continuous
turning-off operation, a temporary turning-on operation and
a temporary turning-off operation, a light emitting diode
(LED) display unit 14 having a plurality of light emitting
diodes, and a reset unit 15 for resetting the operation of
the control unit 1.
As the user operates an operation switch (not shown),
e.g., a slide switch, the first operation setting unit 13
sets one of the automatic operation, the continuous turning-
on operation, the continuous turning-off operation, the
temporary turning-on operation and the temporary turning-off,
operation.
The term "automatic operation" used herein means an
operation state in which the control unit 1 is operated
pursuant to the time schedule stored in the storage unit 6.
The control unit 1 compares the current time measured by the
clock unit 7 with the preset time previously set by the time
setting unit 11. If the current time coincides with the
preset time, the control unit 1 outputs a control signal S1
to the first output unit 5, thereby closing or opening the
contact point 5ab of the first relay 5a.
The term "continuous turning-on operation" used herein
means an operation state in which the control unit 1
continuously closes the contact point 5ab of the first relay
5a regardless of the time schedule stored in the storage
unit 6. The term "continuous turning-off operation" used

herein means an operation state in which the control unit 1
continuously opens the contact point 5ab of the first relay
5a regardless of the time schedule stored in the storage
unit 6.
The term "temporary turning-on operation" used herein
means an operation state in which the control unit 1 closes
the contact point 5ab of the first relay 5a temporarily
(e.g., until the current time measured by the clock unit 7
coincides with the preset time previously set by the time
setting unit 11) regardless of the time schedule stored in
the storage unit 6. The term "temporary turning-off
operation" used herein means an operation state in which the
control unit 1 opens the contact point 5ab of the first
relay 5a temporarily regardless of the time schedule stored
in the storage unit 6.
In this regard, if the temporary turning-on operation
or the temporary turning-off operation is set by the first
operation setting unit 13, the control unit 1 operates
pursuant to the time schedule stored in the storage unit 6,
at the time when the current time measured by the clock unit
7 coincides with the preset time previously set by the time
setting unit 11.
The LED display unit 14 includes an output state
display unit (not shown) which is turned on when the contact
point 5ab of the first relay 5a is in a closed state and a
power connection state display unit (not shown) which is

turned on when an electric power is supplied from the power
supply unit 2.
Referring to Fig. 3, each of the slave devices 20 of
the time switch in accordance with the present embodiment
includes a control unit 23 having, e.g., a microcomputer,
and a power supply unit 24 electrically connected to the
commercial power supply AC via a pair of power supply
terminals 32. Each of the slave devices 20 further includes
a second output unit 25 provided with the aforementioned
second relay 25a and a synchronization signal receiving unit
27 for receiving the synchronization signal transmitted from
the synchronization signal transmitting unit 8 of the master
device 10, through a pair of signal input terminals 34.
An oscillation unit 31 for outputting a system clock
signal to operate the control unit 23 is connected to the
control unit 23.
Responsive to the synchronization signal received by
the synchronization signal receiving unit 27, the control
unit 23 outputs to the second output unit 25 a control
signal S2 for controlling the second output unit 25.
The power supply unit 24 includes a step-down circuit
24a for stepping down an AC voltage inputted from the
commercial power supply AC through the power supply
terminals 32 and a DC conversion circuit 24b for converting
the AC voltage stepped down by the step-down circuit 24a to
a DC voltage. The power supply unit 24 outputs the DC

voltage from the DC conversion circuit 24b to the control
unit 23 and the second output unit 25.
The second output unit 25 includes the aforementioned
second relay 25a and a drive circuit 25b for driving the
second relay 25a based on the control signal S2 outputted
from the control unit 23. The second relay 25a includes a
contact point 25ab having a contact point c containing
contact points a and b. The contact point a of the contact
point 25ab is arranged in a power feeding path extending
from the commercial power supply AC to the load L2. In the
time switch of the present embodiment, the contact point
25ab of the second relay 25a has a contact voltage.
Alternatively, the contact point 25ab may be a voltage-free
contact point.
In the time switch of the present embodiment, the load
L2 is electrically connected to two load connecting
terminals 33a and 33b out of three load connecting terminals
33a, 33b and 33c. Two load connecting terminals 33a and 33b
out of three load connecting terminals 33a, 33b and 33c are
electrically connected to the contact point a of the contact
point 25ab of the second relay 25a. Two load connecting
terminals 33a and 33c out of three load connecting terminals
33a, 33b and 33c are electrically connected to the contact
point b of the contact point 25ab of the second relay 25a.
In the time switch of the present embodiment, the closing or
opening operation of the contact point 25ab of the second

relay 25a will be described as the closing or opening
operation of the contact point a of the contact point 25ab.
The contact point 25ab of the second relay 25a will be
described as a voltage contact point.
The second relay 25a closes or opens the contact point
25ab of the second relay 25a in synchronization with the
closing or opening operation of the contact point 5ab of the
first relay 5a. In the time switch of the present
embodiment, for example, the contact point 25ab of the
second relay 25a is closed in synchronization with the
closing operation of the contact point 5ab of the first
relay 5a so that the loads L1 and L2 are turned on at the
preset time previously set by the time setting unit 11.
More specifically, in the time switch of the present
embodiment, the control unit 23 of each of the slave devices
2 0 outputs the control signal S2 to the second output unit
25 in response to the synchronization signal received by the
synchronization signal receiving unit 27. Accordingly, the
drive circuit 25b of the second output unit 25 immediately
drives the second relay 25a based on the control signal S2
outputted from the control unit 23, thereby closing the
contact point 25ab of the second relay 25a.
Thus, in the time switch of the present embodiment, if
the loads L1 and L2 are to be controlled at the same time,
the contact point 25ab of the second relay 25a is closed or
opened in each of the slave devices 20, in synchronization

with the closing or opening operation of the contact point
5ab of the first relay 5a of the master device 10. For that
reason, it becomes unnecessary to perform a setting task for
controlling the loads L1 and L2 at the same time. In the
time switch of the present embodiment, therefore, as
compared with a case where the conventional time switches
disclosed in Patent Document 2 are used in multiple numbers,
it becomes easy to perform a setting task for controlling
the loads L1 and L2 at the same time.
In the time switch of the present embodiment, the
contact point 25ab of the second relay 25a is closed or
opened in each of the slave devices 20, in synchronization
with the closing or opening operation of the contact point
5ab of the first relay 5a of the master device 10.
Therefore, unlike the conventional time switch disclosed in
Patent Document 1, there is no need to allot individual
addresses to the respective relays 5a and 25a. This makes
it easy to perform a setting task for controlling the loads
L1 and L2.
Each of the slave devices 20 further includes a second
operation setting unit 28 for setting the closing and
opening operation of the contact point 25ab of the second
relay 25a regardless of the closing and opening operation of
the contact point 5ab of the first relay 5a of the master
device 10. More specifically, each of the slave devices 20
includes the second operation setting unit 28 for setting

one of an automatic operation, a continuous turning-on
operation, a continuous turning-off operation, a temporary
turning-on operation and a temporary turning-off operation.
Responsive to the manipulation of an operation switch
(not shown), e.g., a slide switch, the second operation
setting unit 28 sets one of an automatic operation, a
continuous turning-on operation, a continuous turning-off
operation, a temporary turning-on operation and a temporary
turning-off operation.
The term "automatic operation" used herein means an
operation state in which the control unit 23 operates in
response to the synchronization signal received by the
synchronization signal receiving unit 27. When the
synchronization signal is received by the synchronization
signal receiving unit 27, the control unit 23 outputs a
control signal S2 to the second output unit 25, thereby
closing or opening the contact point 25ab of the second
relay 25a.
The term "continuous turning-on operation" used herein
means an operation state in which the control unit 23
continuously closes the contact point 25ab of the second
relay 25a regardless of the synchronization signal received
by the synchronization signal receiving unit 27. The term
"continuous turning-off operation" used herein means an
operation state in which the control unit 23 continuously
opens the contact point 25ab of the second relay 25a

regardless of the synchronization signal received by the
synchronization signal receiving unit 27.
The term "temporary turning-on operation" used herein
means an operation state in which the control unit 23
temporarily closes the contact point 25ab of the second
relay 25a regardless of the synchronization signal received
by the synchronization signal receiving unit 27. The term
"temporary turning-off operation" used herein means an
operation state in which the control unit 23 temporarily
opens the contact point 25ab of the second relay 25a
regardless of the synchronization signal received by the
synchronization signal receiving unit 27.
In this regard, if the temporary turning-on operation
or the temporary turning-off operation is set by the second
operation setting unit 28, the control unit 23 operates
based on the synchronization signal received by the
synchronization signal receiving unit 27, at the time when
the current time measured by the clock unit 7 of the control
unit 1 of the master device 10 coincides with the preset
time previously set by the time setting unit 11.
In the time switch of the present embodiment, each of
the slave devices 2 0 includes the second operation setting
unit 28 for setting the closing or opening operation of the
contact point 25ab of the second relay 25a regardless of the
closing or opening operation of the contact point 5ab of the
first relay 5a of the master device 10. Therefore, it

becomes possible to cope with a situation where one wishes
to, e.g., temporarily turn off or continuously turn on the
operation state of the load L2 connected to the load
connecting terminals 33a and 33b of the slave devices 20.
Each of the slave devices 20 further includes an LED
display unit 29 having a plurality of light emitting diodes,
a reset unit 30 for resetting the operation of the control
unit 23, and a pair of second signal output terminals 35
connected to the signal input terminals 34 by a pair of
wiring lines Lp as an extended connection.
The LED display unit 2 9 includes an output state
display unit (not shown) which is turned on when the contact
point 25ab of the second relay 25a is in a closed state and
a power connection state display unit (not shown) which is
turned on when an electric power is supplied from the power
supply unit 24.
In the time switch of the present embodiment, the
master device 10 provided with the time setting unit 11 and
the first relay 5a and at least one slave device 2 0 provided
with the second relay 25a are separately formed. It is
therefore possible to provide a required number of relays 5a
and 25a just in conformity with the number of loads L1 and
L2 as control targets. In the time switch of the present
embodiment, each of the slave devices 20 is provided with
the second signal output terminals 35 connected to the
signal input terminals 34 as the extended connection. It is

therefore possible to additionally install the slave devices
20 by connecting two-wire signal lines Ls to the second
signal output terminals 35.
Next, description will be made on one example of the
timer control of the loads L1 and L2 performed by the time
switch of the present embodiment. In the subject
specification, there will be described a case where the time
switch is provided with two slave devices 20. Moreover, it
is assumed that the storage unit 6 stores, as a time
schedule, the preset time previously set by the time setting
unit 11.
In the master device 10, if the operation state is set
to an automatic operation by the operation switch of the
first operation setting unit 13, the control unit 1 operates
in accordance with the time schedule stored in the storage
unit 6. More specifically, the control unit 1 first
compares the current time measured by the clock unit 7 with
the preset time stored in the storage unit 6. Then, if the
current time coincides with the preset time, the control
unit 1 outputs a control signal S1 to the first output unit
5 while generating the aforementioned synchronization
signal.
The drive circuit 5b of the first output unit 5 drives
the first relay 5a based on the control signal S1 outputted
from the control unit 1, thereby closing or opening the
contact point 5ab of the first relay 5a. When the contact

point 5ab of the first relay 5a is kept in a closed state,
the control unit 1 turns on the output state display unit.
The synchronization signal transmitting unit 8 transmits the
synchronization signal generated by the control unit 1 to
the slave devices 20 via the signal lines Ls.
In each of the slave devices 20, meanwhile, if the
operation state is set to an automatic operation by the
operation switch of the second operation setting unit 28,
the control unit 23 outputs a control signal S2 to the
second output unit 25 when the synchronization signal
receiving unit 27 receives the synchronization signal
transmitted from the synchronization signal transmitting
unit 8 of the master device 10. The drive circuit 25b of
the second output unit 25 drives the second relay 25a based
on the control signal S2 outputted from the control unit 23,
thereby closing or opening the contact point 25ab of the
second relay 25a. When the contact point 25ab of the second
relay 25a is kept in a closed state, the control unit 23
turns on the aforementioned output state display unit.
Each of the slave devices 2 0 sends the synchronization
signal, which is transmitted from the synchronization signal
transmitting unit 8 of the master device 10 and inputted to
the signal input terminals 34 through the signal lines Ls,
to the second signal output terminals 35 through the
aforementioned wiring lines Lp. In other words, the front
slave device 20 sends the synchronization signal inputted to

the signal input terminals 34, to the rear slave device 20
connected to the two-wire signal lines Ls through the second
signal output terminals 35. The timer control of the load
L2 performed by the rear slave device 2 0 is the same as the
timer control of the load L2 performed by the front slave
device 20. Therefore, description will be omitted on the
timer control of the load L2 performed by the rear slave
device 20.
In each of the slave devices 20, if the operation
state is set to the continuous turning-on operation or the
continuous turning-off operation by the operation switch of
the second operation setting unit 28, the control unit 23
outputs a control signal S2 to the second output unit 25
regardless of the synchronization signal received by the
synchronization signal receiving unit 27. The drive circuit
25b of the second output unit 25 drives the second relay 25a
based on the control signal S2 outputted from the control
unit 23, thereby continuously closing or opening the contact
point 25ab of the second relay 25a.
In each of the slave devices 20, if the operation
state is set to a temporary turning-on operation or a
temporary turning-off operation by the operation switch of
the second operation setting unit 28, the control unit 23
outputs a control signal S2 to the second output unit 25
regardless of the synchronization signal received by the
synchronization signal receiving unit 27. The drive circuit

25b of the second output unit 25 drives the second relay 25a
based on the control signal S2 outputted from the control
unit 23, thereby temporarily closing or opening the contact
point 25ab of the second relay 25a. When the current time
measured by the clock unit 7 of the control unit 1 of the
master device 10 coincides with the preset time previously
set by the time setting unit 11, the control unit 23
operates in accordance with the synchronization signal
received by the synchronization signal receiving unit 27.
As the above, the time switch of the present
embodiment includes the master device 10 and at least one
slave device 20. The second relay 25a of each of the slave
devices 20 closes or opens the contact point 25ab of the
second relay 25a in synchronization with the closing or
opening operation of the contact point 5ab of the first
relay 5a of the master device 10. It is therefore possible
to provide a required number of relays 5a and 25a just in
conformity with the number of loads L1 and L2 as control
targets. Moreover, it becomes easy to perform a setting
task for controlling the loads L1 and L2 at the same time.
(Second Embodiment)
Next, a time switch in accordance with a second
embodiment will be described with reference to Figs. 4
through 6.
The time switch of the present embodiment is identical
in basic configuration with the time switch of the first

embodiment. As shown in Fig. 4, the time switch of the
present embodiment differs from the time switch of the first
embodiment in terms of the portion for connecting the master
device 10 and the slave devices 20. The same components as
those of the first embodiment will be designated by like
reference symbols with the description thereon omitted
appropriately.
The master device 10 includes a first connector unit
37 provided with the pair of first signal output terminals
22.
Each of the slave devices 20 includes a second
connector unit 3 6 provided with the pair of signal input
terminals 34 and a third connector unit 45 provided with the
pair of second signal output terminals 35. The second
connector unit 36 is removably connected to the first
connector unit 37 of the master device 10.
The second connector unit 36 is provided with a pair
of protrusion portions 36a individually covering side
portions of the respective signal input terminals 34. In
the first connector unit 37, there is formed a pair of
recess portions 37a into which the protrusion portions 36a
of the second connector unit 36 can be removably inserted,
respectively. The pair of first signal output terminals 22
is respectively accommodated and arranged within the recess
portions 37a of the first connector unit 37.
In the time switch of the present embodiment, the

first signal output terminals 22 of the master device 10 and
the signal input terminals 34 of each of the slave devices
20 are electrically connected to each other by inserting the
protrusion portions 36a of the second connector unit 36 of
each of the slave devices 20 into the recess portions 37a of
the first connector unit 37 of the master device 10,
respectively.
Thus, in the time switch of the present embodiment,
the protrusion portions 36a of the second connector unit 36
of each of the slave devices 2 0 can be removably connected
to the recess portions 37a of the first connector unit 37 of
the master device 10. Therefore, as compared with the time
switch of the first embodiment, it becomes easy to perform
the task of connecting the master device 10 and the slave
devices 20 to each other.
In the third connector unit 45 of the slave device 20,
there are formed a pair of recess portions 45a into which
the protrusion portions 36a of the second connector unit 36
of another slave device 20 can be removably inserted. In
other words, the second connector unit 36 of the rear slave
device 20 is shaped so that the second connector unit 36 can
be removably connected to the third connector unit 45 of the
front slave device 20. The second signal output terminals
35 are accommodated and arranged within the recess portions
45a of the third connector unit 45, respectively.
Thus, in the time switch of the present embodiment,

the protrusion portions 36a of the second connector unit 36
of the rear slave device 20 can be removably connected to
the recess portions 45a of the third connector unit 45 of
the front slave device 20. Therefore, as compared with the
time switch of the first embodiment, it becomes easy to
perform the task of connecting the front slave device 20 and
the rear slave device 20 to each other.
Circular cover members 38 covering the insertion holes
of the recess portions 37a are arranged in the respective
recess portions 37a of the first connector unit 37 of the
master device 10. The cover members 38 can be opened or
closed as the protrusion portions 36a of the second
connector unit 3 6 of each of the slave devices 2 0 are
inserted or removed. The external size of each of the cover
members 38 is set a little smaller than the opening
dimension of each of the recess portions 37a.
The third connector unit 45 of each of the slave
devices 20 has the same structure as the first connector
unit 37 shown in Fig. 6A. Therefore, no description will be
made on the third connector unit 45. The external size of
each of the cover members of the third connector unit 45 is
set a little smaller than the opening dimension of each of
the recess portions 45a.
As the above, in the time switch of the present
embodiment, the cover members 38 and the cover members
described above can be opened or closed as the protrusion

portions 36a of the second connector unit 36 are inserted
into or removed from the respective recess portions 37a of
the first connector unit 37 and the respective recess
portions 45a of the third connector unit 45. It is
therefore possible to prevent foreign materials (e.g., ants,
particles and dust) from entering the respective recess
portions 37a of the first connector unit 37 and the
respective recess portions 45a of the third connector unit
45.
(Third Embodiment)
Next, a time switch in accordance with a third
embodiment will be described with reference to Fig. 7.
The time switch of the present embodiment is identical
in basic configuration with the time switch of the second
embodiment. As shown in Fig. 7, the time switch of the
present embodiment differs from the time switch of the
second embodiment in that an electric current is supplied
from the master device 10 to the slave devices 20. The same
components as those of the second embodiment will be
designated by like reference symbols with the description
thereon omitted appropriately.
The master device 10 includes a pair of power supply
output terminals 39 electrically connected to the commercial
power supply AC via the pair of power supply terminals 19.
One of the power supply output terminals 39 is electrically
connected to one of the power supply terminals 19 via a

power supply contact point 40 which is switched on or off by
the manipulation of an operation unit not shown.
Each of the slave devices 20 includes a pair of power
supply input terminals 41 electrically connectable to the
power supply output terminals 39 of the master device 10 and
a pair of power supply output terminals 42 connected to the
power supply input terminals 41 through a pair of power
lines Lv, as an extended connection. The power supply input
terminals 41 of one of the slave devices 2 0 are electrically
connectable to the power supply output terminals 42 of the
other slave device 20. The power supply input terminals 41
of each of the slave devices 20 are electrically connected
to the step-down circuit 24a of the power supply unit 24
(see Fig. 3) .
In the slave devices 20, the power supply input
terminals 41 are arranged in the second connector unit 36.
The power supply output terminals 39 electrically
connectable to the power supply input terminals 41 of the
second connector unit 36 of each of the slave devices 20 are
arranged in the first connector unit 37 of the master device
10.
In the time switch of the present embodiment, the
power supply output terminals 39 of the master device 10 and
the power supply input terminals 41 of one of the slave
devices 20 are electrically connected to each other by
interconnecting the second connector unit 36 of the slave

device 20 and the first connector unit 37 of the master
device 10.
Accordingly, in the time switch of the present
embodiment, the power supply input terminals 41 of the
second connector unit 36 can be removably connected to the
power supply output terminals 39 of the first connector unit
37 of the master device 10.
In the time switch of the present embodiment, the
power supply contact point 40 is switched on by the
manipulation of the aforementioned operation unit after the
power supply input terminals 41 of the second connector unit
36 of one of the slave devices 20 are electrically connected
to the power supply output terminals 39 of the first
connector unit 37 of the master device 10. This makes it
possible to supply an electric power from the master device
10 to the slave devices 20. Accordingly, it becomes
unnecessary, in the slave devices 2 0 of the time switch of
the present embodiment, to use a pair of power supply
terminals 32 electrically connected to the commercial power
supply AC. It is therefore possible to reduce the size of
the slave devices 20.
In the time switch of the present embodiment, further,
the power supply input terminals 41 of the second connector
unit 36 of each of the slave devices 2 0 can be removably
connected to the power supply output terminals 39 of the
first connector unit 37 of the master device 10. Moreover,

an electric power can be supplied from the master device 10
to the slave devices 20. Therefore, as compared with the
time switch of the second embodiment, it becomes easy to
perform the power supply line wiring task in the time
switch.
In the time switch of the present embodiment, the
first signal output terminals 22 and the signal input
terminals 34 are used as the synchronization signal transfer
paths existing between the master device 10 and the slave
devices 20. However, the present invention is not limited
thereto. For example, the power supply output terminals 39
and the power supply input terminals 41 may be used as the
synchronization signal transfer paths. In this case, a
power line communication (PLC) technology may be employed as
the technology for transmitting the synchronization signal
through the use of the power supply output terminals 39 and
the power supply input terminals 41.
The respective embodiments described above may be used
in combination.
While certain preferred embodiments of the present
invention have been described above, the present invention
is not limited to these specific embodiments but may be
modified or changed in many different forms without
departing from the spirit and scope of the invention defined
in the claims. Such modifications and changes shall be
construed to fall within the scope of the invention.

WE CLAIM:
1. A time switch, comprising:
a master device including a time setting unit for
setting a time and a first relay arranged in a power supply
path extending to a first load, the master device having a
function of controlling the first relay at the time set by
the time setting unit; and
at least one slave device including a second relay
arranged in a power supply path extending to a second load,
wherein the second relay is configured to close or open
a contact point of the second relay in synchronization with
a closing or opening operation of a contact point of the
first relay.
2. The time switch of claim 1, wherein the master device
includes a first connector unit provided with a first signal
output terminal, through which a synchronization signal is
outputted, to synchronize the closing or opening operation
of the contact point of the second relay with the closing or
opening operation of the contact point of the first relay,
wherein the slave device includes a second connector
unit provided with a signal input terminal through which the
synchronization signal is inputted and detachably connected
to the first connector unit, and a third connector unit
provided with a second signal output terminal, the second

signal output terminal being connected to the signal input
terminal as an extended connection, and
wherein the second connector unit of the slave device
has a shape which is detachably connectable to the third
connector unit of another slave device.
3. The time switch of claim 2, wherein the slave device is
supplied with an electric power from the master device.
4. The time switch of claim 2 or 3, wherein each of the
first connector unit and the third connector unit has a
recess portion into which the second connector unit having a
protrusion portion is detachably inserted, and wherein a
cover is provided to open and close an insertion hole of the
recess portion.
5. The time switch of any one of claims 1 to 4, wherein
the slave device includes an operation setting unit capable
of setting the closing or opening operation of the contact
point of the second relay regardless of the closing or
opening operation of the contact point of the first relay.
6. The time switch of claim 1, wherein the master device
includes only one first relay and the slave device includes
only one second relay.