JP2640727B2 - Safety device of thermal storage control means in thermal storage nap mat for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for heat storage control means in a heat storage nap mat mainly used for long-distance transportation vehicles.

[0002]

2. Description of the Related Art A conventional heat storage nap mat is configured to automatically stop heat storage when a predetermined temperature is reached by a temperature switch provided for each heat storage element, and to select one of the heat storage elements. As a representative, an alarm is sounded when the power supply to the power supply is stopped.

[0003]

It is difficult to represent each heat storage state of a plurality of heat storage elements with a single specified heat storage element. When the alarm is issued, turn the power switch OFF.
If the temperature is changed to F or the power cable is disconnected, insufficient heat storage may occur.

For this purpose, it is electrically confirmed that all of the plurality of heat storage units have reached a predetermined temperature and each of the temperature switches has been activated, and then an alarm buzzer is sounded, so that heat storage shortage occurs. The body disappears and sufficient heat storage preparation becomes possible.

[0005] However, if a DC drive electric circuit for electrically confirming that each temperature switch has been activated and for sounding an alarm buzzer is provided, even if a heating appliance such as an electric heater is a DC power supply, an applied voltage is not applied. Has been conventionally used so as to ignore the polarity of the power supply connection cable, there is a possibility that the power supply connection cable may be connected to the opposite polarity.

In particular, a connector for a power cable of a vehicle-mounted electric heating apparatus uses a connection plug for an AC power supply, which is simply used in a non-polar manner, and is conventionally used. In addition, there is a possibility that connection may be made by mistake.

The present invention has been made in view of the above circumstances, and provides a safety device for a heat storage control means in a vehicle heat storage type nap mat which can operate irrespective of the polarity of a DC power supply applied from the outside. is there. Another object of the present invention is to
It is an object of the present invention to provide a safety device for a heat storage control means in a vehicle heat storage type nap mat which has a simple configuration and can be easily connected to a power supply. It is another object of the present invention to provide a safety device for a heat storage control means in a vehicle heat storage type nap mat which can warn of a power supply connection error.

[0008]

According to the first aspect of the present invention, there is provided a safety device for a heat storage control means in a vehicle heat storage type nap mat, comprising a plurality of heat storage units each including a latent heat storage element and an electric heater. In the on-board thermal storage nap mat, a temperature switch is connected in series to the electric heater of each heat storage unit, and each of the heat storage units is connected in parallel, and the electric heater is energized by a DC power supply externally applied. On the other hand, among the plurality of temperature switches, a detection notifying unit that detects opening of a predetermined temperature switch and operates with a DC power supply that notifies that the heat storage unit has reached a predetermined temperature, and a DC applied externally. And a power supply polarity converting means for converting a power supply voltage into a polarity suitable for the detection notifying means and applying the converted voltage to the detection notifying means.

In particular, the detection notifying means includes: a bidirectional photocoupler whose output transistor is conductive when a voltage at a connection point between the temperature switch and the electric heater has a predetermined magnitude irrespective of its polarity; And a notification sound generating element that is activated by the output transistor of the bidirectional photocoupler to generate an electronic sound. Further, it is preferable that the power supply polarity conversion means includes a full-wave rectifier circuit using a diode bridge.

According to a fourth aspect of the present invention, there is provided a safety device for a heat storage control means in a vehicle heat storage nap mat according to the invention, wherein the vehicle heat storage nap mat includes a plurality of heat storage units each including a latent heat storage element and an electric heater. A temperature switch provided in series with the electric heater of each heat storage unit, a DC power supply for applying a DC voltage to a series circuit of the electric heater and the temperature switch, and a voltage at a connection point between the electric heater and the temperature switch in each heat storage unit. An AND circuit that detects and calculates the logical product of the ON-OFF states of the temperature switches of each heat storage unit and an alarm circuit that sounds an alarm buzzer according to the output of the AND circuit when all the temperature switches reach the same state. The above problem is solved by providing a bridge type DC rectifier circuit in the power supply of the alarm circuit.

The AND circuit preferably has a Zener diode for forward overvoltage protection at each input terminal of the AND circuit. The bridge type DC rectifier circuit,
It is preferable that a Zener diode for forward overvoltage protection is provided at the DC output terminal of the bridge type DC rectifier circuit.

[0012]

According to the first aspect of the present invention, when the temperature switch reaches a predetermined temperature and is opened by the heat generated by the electric heater in a predetermined one of the plurality of heat storage units, the temperature switch is opened. Is detected by the detection notifying means, and the notifying operation is started, so that the user can recognize that the heat storage unit has reached the appropriate temperature state. In addition, since a DC power supply voltage applied from the outside is applied to the detection notification means so as to match the power supply polarity of the detection notification means by the power supply polarity conversion means, the application of the DC power supply voltage from the outside is not required. This can be performed without considering the polarity.

According to the present invention, when the power plug is erroneously connected to the DC power supply with the opposite polarity or when the power plug is erroneously connected to the AC power supply, an alarm buzzer sounds immediately and the connection mistake is made. It is safe to warn.
When the connection is normally made, an alarm buzzer sounds when all the heat storage units have completed the heat storage.

[0014]

FIG. 1 shows an embodiment of the present invention according to claims 4 to 6, and the present invention is applied to a vehicle-mounted regenerative nap mat 1 shown in FIG.

The nap mat 1 (see FIG. 2) is used in a long-distance transportation vehicle, and utilizes a power generated during traveling while driving the vehicle, and a latent heat storage element 2 and a heat storage element which are sealed as required. A plurality of heat storage units 4 having heaters 3
In addition, the generated electric power during traveling is converted into heat via the electric heater 3 and stored in the heat storage body 2, and when the vehicle is stopped and the driver takes a nap, warming is performed using the stored heat. It is intended to be taken.

According to the present invention, the heat storage control of the plurality of heat storage units 4 used in the nap mat 1 is safely controlled by the heat storage control circuit of FIG.

Each heat storage unit 4 is provided with a temperature fuse 5 for preventing abnormal heating and a thermostat-type temperature switch 6 for detecting an appropriate heating temperature, wherein the latent heat storage material is stored in a flat bag. It is provided in close contact with substantially the center of the surface opposite to the electric heater 3 which is in close contact with one surface of the latent heat storage element 2.

FIG. 1 is an electric circuit diagram of an embodiment in which the safety device of the present invention is added to heat storage control means for storing heat in each of the heat storage units 4 using a DC power supply of an automobile.

Each electric heater 3 in each heat storage unit 4
Is connected through a temperature fuse 5 and a temperature switch 6 in series.
Each of the heat storage units 4 is connected to a positive electrode line 7a of the DC power supply line 7 so that the DC voltage E1 is applied from a DC power supply line 7 connected to a DC power supply such as a storage battery in an automobile.
And a negative electrode line 7b.

When the temperature switch 6 reaches a predetermined temperature, a switch of a type that opens a contact point is used. Therefore, when the temperature of the electric heater 3 reaches a predetermined temperature, the power is cut off.
Heating is stopped.

Reference numeral 8 denotes an alarm circuit for detecting that all the temperature switches 6 of each heat storage unit 4 have reached a predetermined temperature and generating an alarm. The alarm circuit 8 rectifies the current from the DC power supply line 7 via the fuse 9, once through the bridge type full-wave rectifier 10, and further through the current limiting resistor 11 for overvoltage protection in series. 8, the power supply voltage E2 is taken out, and the power supply voltage E2 is used to turn on the light-emitting diode 12 for power supply display.

At the output terminal of the current limiting resistor 11 for obtaining the power supply voltage E2, a Zener diode 13 for overvoltage protection is provided. Reference numeral 14 denotes a capacitor for stabilizing the operation of the alarm circuit 8.

The power supply voltage E2 includes three photocouplers 1
5, 16, 17 transistors 15a, 16a, 17
An alarm buzzer 18 is inserted in series with the circuit in which a is connected in series. The resistor 19 in series with the current limiting resistor 11 is a resistor 2 in series with the voltage-dividing resistor for generating the required power supply voltage E2, the light emitting diode 12, and the alarm buzzer 18, respectively.
Reference numerals 0 and 21 are current limiting resistors for limiting the current value.

The light emitting diodes 15b, 16b and 17b of the photocouplers 15, 16 and 17 have their cathodes connected in common to the negative electrode of the power supply voltage E2, and their anodes connected to one end of the electric heater 3 of each heat storage unit 4. The connection point a with the temperature switch 6 is connected via an overvoltage protection circuit 38 in which a current limiting resistor 22, a current limiting resistor 23, and a Zener diode 24 are connected in series. The other end of each electric heater 3 is commonly connected to a positive electrode line 7 a of a DC power supply line 7. The temperature switch 6 is connected to the negative electrode line 7b.

When the temperature switch 6 reaches a predetermined temperature and is turned OFF, the anode side of the light emitting diodes 15b, 16b, and 17b becomes the positive voltage of the DC voltage E1. The light emitting diodes 15b of the photocouplers 15, 16, 17
16b and 17b are turned on, and the corresponding transistor 15a,
16a and 17a conduct, and the alarm buzzer 18 sounds.

The photocouplers 15, 16, 17 constitute an AND circuit 25 in which the output result of sounding the alarm buzzer 18 is expressed by a logical product with respect to the input status of the respective light emitting diodes 15b, 16b, 17b. ing.

As described above, when the plurality of heat storage units 4 used in the nap mat 1 reach the respective predetermined temperatures and end the heat storage, the temperature switches 6 cut off the heating power and the alarm circuit. 8 sends a signal
When all the temperature switches 6 are turned off, the AND circuit 25
Detects this, sounds the alarm buzzer 18, and turns off the power switch 26 by this alarm sound, or removes the plug 28 connecting the power cable 27 to the power supply from a socket (not shown).

When the plug 28 is connected to a DC power supply and the polarity is erroneously connected, for example,
When the DC voltage E1 is applied with the positive and negative lines 7a and 7b of the DC power supply line 7 having opposite polarities, one end of the electric heater 3 of each heat storage unit 4 and the temperature switch which should become positive when heat storage heat is completed. 6 is directly positive, and the power supply voltage E2 of the alarm circuit 8 is always obtained through the full-wave rectifier 10, regardless of the polarity of the DC power supply line 7. Therefore, the AND circuit 25 operates normally and the alarm buzzer 18 of the alarm circuit 8 operates.
Sounds.

Further, when the plug 28 is erroneously connected to a commercial AC power supply, the power supply voltage E2 of the alarm circuit 8 can be obtained as a DC voltage maintained at the Zener voltage by the Zener diode 13 for overvoltage protection, and An AC voltage is directly applied to a connection point a between one end of the electric heater 3 and the temperature switch 6, but an input of each of the light emitting diodes 15b, 16b, 17b of the photocouplers 15, 16, 17 is provided with a current limiting resistor. Since the overvoltage protection circuit 38 in which the zener diode 23 and the zener diode 24 are connected in series is provided, a positive half-wave rectified voltage whose upper end is clipped by the zener voltage of the zener diode 24 is applied.

Since this positive half-wave rectified wave is simultaneously applied to the three photocouplers 15, 16 and 17, the AND circuit 25 operates during this period to sound the alarm buzzer 18 intermittently.

Next, an embodiment of the safety device of the heat storage control means in the heat storage type nap mat mounted on a vehicle according to the present invention will be described with reference to FIG. First, in the case of the circuit configuration shown in FIG. 1, when the plug 28 is connected to the DC power supply with the wrong polarity or when the plug 28 is connected to the AC power supply by mistake as described above, an alarm is immediately issued. Since the buzzer 18 sounds, there is an advantage that the user can immediately recognize that the connection is inappropriate. However, when the alarm buzzer 18 sounds, The connection operation must be performed again, and when the plug 28 is connected to the power supply, it must be confirmed that the power supply is a DC power supply and the polarity must be confirmed, and the connection operation is troublesome.

The invention according to claims 1 to 3 has been made in order to solve such a problem. The invention relates to a heat storage control means for a vehicle heat storage type nap mat which can operate regardless of the polarity of a connected DC power supply. A safety device is provided.

Hereinafter, the present apparatus will be described with reference to FIG. The same components as those shown in FIG. 1 are denoted by the same reference numerals. The present invention is also applied to the on-board thermal storage nap mat 1 shown in FIG. 2 and controls the thermal storage of the plurality of thermal storage units 4 used in the nap mat 1 by using the thermal storage shown in FIG. The point that the control is performed safely by the control circuit is the same as the above-described invention. The heat storage units 4a to 4c include a temperature fuse 5 which is blown at a predetermined temperature, an electric heater 3,
Temperature switch 6 that is opened when the temperature exceeds a predetermined temperature
Are connected in series in this order.

The heat storage units 4a to 4c having the same configuration as in the embodiment of FIG. 1 are connected in parallel, and one end of each thermal fuse 5 is connected to one end of the power switch 26.
One end of each temperature switch 6 is connected to one end of the plug 28 and the input terminal 10b of the full-wave rectifier 10, respectively. Therefore, when the plug 28 is connected to a predetermined DC power supply and the power switch 26 is closed, the DC power supply voltage is applied to each of the heat storage units 4a to 4c at the same time. One end of the power switch 26 is connected to the input terminal 1 of the full-wave rectifier 10 via a fuse 37.
0a.

In the present embodiment, of the three heat storage units 4a to 4c, the temperature switch 6 of the heat storage unit 4a is higher than the temperature switches 6 of the other heat storage units 4b and 4c after the application of the DC power supply voltage. Since the opening state is delayed, the open / close signal of the temperature switch 6 is taken out from a connection point c between the electric heater 3 of the heat storage unit 4a and the temperature switch 6 to an alarm circuit 8A to be described later. That is, the connection point c is
Are connected to the other ends of the light emitting diodes 30a and 30b (details will be described later).

The other end of the power switch 26 is connected to the other end of the plug 28 via the fuse 31. The power switch 26 is housed so that the light emitting surface of the light emitting diode 12 is located on the outer surface of the case 26a (see FIG. 2). And the light emitting diode 12
Has a cathode connected to the output terminal 10d of the full-wave rectifier 10 and an anode connected to the output terminal 10d of the full-wave rectifier 10 via the resistor 20.
c is connected to each other, and is lit when the plug 28 is connected to the power supply and the voltage is normally applied, so that the user can visually confirm that the power supply voltage has been applied. Has become.

The alarm circuit 8A as the detection notifying means is adapted to sound the alarm buzzer 18 when detecting the open state of the temperature switch 6 of the heat storage unit 4a. The alarm circuit 8A according to the present embodiment mainly includes a photocoupler 30, an alarm buzzer 18 as a notification sound generating element, and a full-wave rectifier 10.

The photocoupler 30 is a so-called bidirectional type having light-emitting diodes 30a and 30b connected in anti-parallel and transistors 30c and 30d connected in Darlington. One end of each of the light-emitting diodes 30a and 30b is connected to one end. Is connected to one end of the plug 28 via a resistor 32. A resistor 3 is connected between a connection point between the resistor 32 and the plug 28 and one end of the power switch 26.
3, 34 are connected. Further, the connection point between the resistors 33 and 34 is connected to the connection point between the temperature switch 6 of the heat storage unit 4a and the other ends of the light emitting diodes 30a and 30b.

Therefore, the temperature switch 6 is closed until the electric heater 3 of the heat storage unit 4a generates heat and the temperature switch 6 is opened at a predetermined temperature.
The resistor 33 is in a short-circuit state, and the series portion of the resistor 32 and the light emitting diodes 30a and 30b is also in a short-circuit state. On the other hand, one end of an alarm buzzer 18 is connected to the collectors of the transistors 30c and 30d.
8 is connected to the output terminal 1 of the full-wave rectifier 10 via a resistor 35.
0c, and the positive terminal of the electrolytic capacitor 36 is connected.

The negative terminal of the electrolytic capacitor 36 is connected to the emitter of the transistor 30d and to the output terminal 10d of the full-wave rectifier 10, and the output voltage of the full-wave rectifier 10 is connected via the resistor 35. The voltage is applied to the electrolytic capacitor 36. Therefore, when one of the light emitting diodes 30a and 30b emits light and the transistors 30c and 30d conduct, the alarm buzzer 18 is energized and an alarm sound is generated.
The full-wave rectifier 10 serving as a power supply polarity conversion means is a known full-wave rectifier in which a bridge circuit is configured by a rectifying diode. Positive electrode, output terminal 1
A DC voltage is output so that 0d is a negative electrode.

Next, the operation of the present apparatus having the above configuration will be described. First, in a state where the power switch 26 is opened, the plug 28 is connected to a DC power supply (not shown) so as to have a polarity indicated by “+, −” in FIG.
Subsequently, when the power switch 26 is closed, the DC power supply voltage is directly applied to the three heat storage units 4a to 4c, and the electric heaters 3 gradually generate heat.

On the other hand, the DC power supply voltage is also directly applied to the input terminals 10a and 10b of the full-wave rectifier 10, and the output terminal 1
Since substantially the same DC voltage is extracted from 0c and 10d, the light emitting diode 12 is turned on and the user can recognize that the heat generating unit 4 is turned on. The DC voltage output from the full-wave rectifier 10 is supplied to the electrolytic capacitor 3 via the resistor 35.
6 and the capacitor 36 is substantially connected to the full-wave rectifier 1.
The voltage is output from 0.

Immediately after the heat storage units 4a to 4c are turned on, the temperature switch 6 is closed, so that the resistor 33 is short-circuited and the series connection of the resistor 32 and the light emitting diodes 30a, 30b. Are also short-circuited, and no current flows through the light-emitting diodes 30a and 30b, so they are off and the alarm buzzer 1
8 does not ring. And the heat storage units 4a ~
4c, the heat generation state of the electric heater 3 progresses, and particularly when the temperature reaches a predetermined temperature at which the temperature switch 6 of the heat storage unit 4a is opened, the temperature switch 6 is opened, and the short-circuit state of the resistor 33 and the resistor 32 and the light emitting diode The short-circuit state of 30a, 30b is released.

Here, since the anode side of the light emitting diode 30a of the photocoupler 30 becomes a positive electrode and a DC voltage is applied from the connection condition of the DC power supply, a current flows through the light emitting diode 30a to be in a light emitting state, and the transistor 3
0c and 30d become conductive, and the alarm buzzer 18
Will sound. Thus, the user can recognize that each of the heat storage units 4a to 4c has reached an appropriate temperature.

Next, it is assumed that the plug 28 is connected to a DC power supply (not shown) so as to have a polarity opposite to that described above, that is, a polarity state indicated by a + or-sign in a circle in FIG. By closing the power switch 26, the DC power supply voltage of the opposite polarity to the previous example is directly applied to the three heat storage units 4a to 4c, but the operation of each of the heat storage units 4a to 4c is Since the polarity of the power supply voltage has no effect, the electric heater 3 starts to generate heat as in the case described above.

On the other hand, the input terminals 10a,
Although a DC voltage having the opposite characteristic to that described above is applied to 10b, the output terminal 1b is operated by the action of the full-wave rectifier 10.
DC voltages are output to 0c and 10d with the same polarity as described above, that is, the polarity shown in FIG. Therefore, a DC voltage is generated in the electrolytic capacitor 36 with the same polarity as before the connection of the plug 28 is changed.

The electric heater 3 of the heat storage unit 4a
When the temperature switch 6 is opened due to a rise in temperature due to the heat generated by the device, a DC voltage is applied so that the anode side of the light emitting diode 30b becomes a positive electrode, so that the light emitting diode 30b is in a light emitting state. , The alarm buzzer 18 sounds. Thus, the user can recognize that each of the heat storage units 4a to 4c has reached an appropriate temperature.

In this embodiment, since the DC power supply voltage supplied from the outside to the alarm circuit 8A is applied through the full-wave rectifier 10, the plug 28 for the DC power supply is applied.
Can be used with a DC power supply without considering the connection direction (polarity).

In this embodiment, the alarm buzzer 18 sounds as the notification sound generating element. However, the alarm buzzer is not limited to this. For example, the electronic sound generated by an electronic circuit may be used. May be output from the speaker. Further, it is not necessary to be limited to the notification sound generating element.
(Liquid Crystal Display), EL (Electronic Lumine)
scence) element or the like may emit light. Also,
In the present embodiment, a configuration in which three heat storage units 4a to 4c are provided is shown. However, it is needless to say that the number of heat storage units 4a to 4c is not limited to three.

[0050]

As described above, according to the first to third aspects of the present invention, a DC power supply can be connected from the outside without considering the polarity of the DC power supply, and the heat storage unit having the electric heater has a predetermined temperature. With such a configuration, it is possible to operate irrespective of the polarity of the DC power supply externally applied, and it is possible to reliably control the temperature of the heat storage unit. In addition, since the opening of one of the plurality of temperature switches is typically detected to notify that the heat storage unit has reached a predetermined temperature, the opening signal of each of the temperature switches is logically ANDed. Compared to a configuration in which the information is obtained and notified, the number of wirings is reduced and an effect is obtained in that the configuration is simplified.

According to the fourth and sixth aspects of the present invention, in the DC power supply, when the polarity of the connection plug 28 is erroneously connected to the AC power supply, the AC power supply should not be connected to the AC power supply. When the plug 28 is mistakenly connected to an outlet or the like, the alarm buzzer 18 sounds at the same time in any case, so that the connection mistake can be quickly noticed, and the mistake can be corrected or canceled in a short time. So safe.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of a safety device of a heat storage control means in a vehicle heat storage type nap mat according to the inventions of claims 4 to 6;

FIG. 2 is a partially cutaway perspective view showing an outline of an in-vehicle thermal storage nap mat to which the present invention is applied.

FIG. 3 is an electric circuit diagram showing an embodiment of a safety device of a heat storage control means in the heat storage type nap mat for vehicle according to the first to third aspects of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Nap mat 2 ... Latent heat storage unit 3 ... Electric heater 4 ... Heat storage unit 5 ... Thermal fuse 6 ... Temperature switch 7 ... DC power supply line 7a ... Positive electrode line 7b ... Negative electrode line 8 ... Alarm circuit 10 ... Full wave rectifier 12 ... Light emitting diode 13 ... Zener diode 14 ... Capacitors 15, 16, 17 ... Photocoupler 15a, 16a, 17a ... Transistor 15b, 16b, 17b ... Light emitting diode 18 ... Alarm buzzer 24 ... Zener diode 25 ... AND circuit 26 ... Power switch 28 ... Plug 30 Photocoupler 30a, 30b Light emitting diode 30c, 30d Transistor a Connection point

Claims (6)

(57) [Claims] An in-vehicle heat storage nap mat including a plurality of heat storage units each including a latent heat storage element and an electric heater, wherein a temperature switch is connected in series to the electric heater of each heat storage unit, and each heat storage unit is connected to the heat storage unit. While the unit is connected in parallel and the electric heater is energized by a DC power supply applied from the outside, the unit detects the opening of a predetermined temperature switch among the plurality of temperature switches, and sets the heat storage unit to a predetermined temperature. Detection notification means operating with a DC power supply for notifying that the power supply has reached the power supply, and power supply polarity conversion means for converting a DC power supply voltage applied from the outside into a polarity suitable for the detection notification means and applying the polarity to the detection notification means. A safety device for heat storage control means in a vehicle heat storage type nap mat, comprising: 2. A bidirectional photocoupler for turning on an output transistor when a voltage at a connection point between a temperature switch and an electric heater has a predetermined magnitude regardless of its polarity; The heat storage device according to claim 1, further comprising: a notification sound generating element that is activated by an output transistor of the bidirectional photocoupler to generate an electronic sound when the output transistor is turned on. Safety device for control means. 3. The safety device according to claim 1, wherein the power supply polarity conversion means includes a full-wave rectifier circuit using a diode bridge. 4. A vehicle-mounted regenerative nap mat including a plurality of heat storage units each including a latent heat storage element and an electric heater, a temperature switch provided in series with the electric heater of each heat storage unit, and an electric heater and a temperature. A DC power supply for applying a DC voltage to a series circuit of switches, a voltage at a connection point between an electric heater and a temperature switch in each heat storage unit is detected, and a logical product of an ON-OFF state of a temperature switch of each heat storage unit is obtained. A circuit, and an alarm circuit that sounds an alarm buzzer in response to the output of the AND circuit when all of the temperature switches reach the same state. A bridge type DC rectifier circuit is provided as a power supply of the alarm circuit. The safety device of the heat storage control means in the heat storage type nap mat for vehicle. 5. The safety device for a heat storage control means in a vehicle heat storage type nap mat according to claim 4, wherein the AND circuit has a Zener diode for overvoltage protection at each input terminal of the AND circuit. 6. The heat storage control means in a vehicle-mounted regenerative nap mat according to claim 4, wherein the bridge type DC rectifier circuit has a Zener diode for overvoltage protection at a DC output terminal of the bridge type DC rectifier circuit. Safety equipment.