DE20306066U1 - Electric motor furniture drive, has locking device with first and second switches and signaling element that signals correct operation and states of locking device - Google Patents

Abstract

The electric motor furniture drive has at least one drive motor (7), at least one hand control (3) with function triggering buttons (S1,S2), at least one switch element (11,12), at least one signaling element (19) and a locking device (30). The locking device has first and second switches and the signaling element signals correct operation and the states of the locking device.

Description

The invention relates to an electromotive furniture drive with at least one drive motor, at least one manual control which has function-triggering buttons, at least one switching element, at least one signaling element and a locking device.

The furniture drives in question are used as drives for many different pieces of furniture in a known manner. For example, in hospitals and/or care facilities, patients in a bed are often not allowed to use all of the bed's adjustment functions. In this case, the functions not available to the patient are switched off by the nursing staff using so-called locking switches. There are various solutions for this. DE 94 04 382 discloses various solutions for integrating these locking functions with an additional device in a hand control.

-25./710/J85-

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BOEHMERT & BOEHMERT

The disadvantage is that these designs do not have the required first-fault safety. To achieve this, these designs would have to be expanded in an uneconomical way.

Furthermore, DE 298 02 532 shows a hand-held control device with a safety device that works with coded signals. The effort required to code and decode the signals is seen as a disadvantage.

The object of the invention is to provide a first-error safe manual control which no longer has the disadvantages mentioned above, is particularly easy to handle and offers additional advantages over the prior art.

The object is achieved in that the locking device includes a first switch and a second switch, and in that the signaling element signals the correct function and the states of the locking device.

Advantageous further training can be found in the subclaims.

The hand control generally has two operating buttons per motor, with which the motor can be driven in one direction or in the opposite direction. The function of these buttons is blocked by a locking device. This locking device is switched on or off by a switching element that can be operated from the outside. A contactless switching element, e.g. a Hall sensor, is preferably used for this purpose. This is arranged inside the hand control and can be easily operated from the outside using a magnet.

The electrical signal of this Hall sensor, which is generated at its output when activated, is temporarily stored in a first and a second switching memory. Each switching memory has an output that is connected to the blocking device via a timing element. The blocking device consists of two switches connected in series, which

BOEHMERT & BOEHMERT

are preferably semiconductor switches. The semiconductor switches are made up of transistors. Each transistor has a switching input, which is connected to the output of a timing element. In a preferred embodiment, the timing elements are made up of a resistor-capacitor combination. Both switching memories are simultaneously put into the memory state by the Hall sensor, but their output signals are fed to the blocking device with a time delay. Thus, the first switch, i.e. the first transistor, is switched on first and shortly afterwards the second transistor. The blocking device is then switched on and connects the operating elements of the manual control to the supply voltage, which can switch the control elements of the motor on and off.

The time delay of the second switching transistor can be varied by an additional capacitor connected to the input of the second switching transistor and to its connection to the first switching transistor.

The blocking device is connected to a signaling element. In a preferred embodiment, the signaling element is a light-emitting diode. However, a multi-colour light-emitting diode and/or an acoustic detector can also be used. The signaling element signals the state of the blocking device through its different intensities or different signal values. The blocking device can assume three different states:

In the first state, only the first switch of the locking device is switched on and the second switch is switched off.

In the second state, the first and second switches of the locking device are switched on, which means that the locking device is completely switched on.

The third state is the locked state of the locking device, in which the first switch and the second switch are off.

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This locked state is signaled by the fact that in the preferred embodiment the LED lights up with a certain intensity value. If the switching element, i.e. the Hall sensor, is activated from the outside, the first switch of the locking device switches on. This is signaled by the LED signaling a higher intensity value. This is indicated by a jump in brightness. A short time later, the second switch of the locking device also switches on. The LED goes out. This enables the three states of the locking device to be easily signaled. At the same time, there is an advantageous way of checking the function of this locking device, namely by showing the three different states in three different intensity values, in this case brightness values of the LED.

Thus, in a particularly advantageous manner, it is possible to signal three different states of the locking device and additionally to check the locking device using a signaling element.

If one of the switches in the locking device fails, this is signaled by the signaling element. There is no danger from motors starting on their own, as the locking device consists of two switching elements.

The electrical connection of the signaling element with the blocking device is made via connections using blocking diodes and/or resistors, which prevent any reaction to the blocking device.

The signaling element can also consist of a so-called three-color LED. In this case, each color is assigned to a different state of the locking device. The signaling element can also be an acoustic detector that reports the different states of the locking device through the intensity of a signal or through different sound sequences.

BOEHMERT & BOEHMERT

Thus, an electric motor-driven furniture drive with a first-fault safe manual operation is created, which has a simple and advantageously economical design, while at the same time offering the user a special advantage through the signaling element, in that this signaling element not only signals the states of the locking device, but also allows the user to check the functionality of the locking device.

The invention is explained in more detail in the following description and the drawings. Here:

Fig. 1 A schematic representation of a furniture drive with a manual control;

Fig. 2 is a block diagram of the hand control according to the invention;

Fig. 3 is an exemplary circuit diagram of a hand control according to the invention; and

Fig. 4 is a diagram of the manual control signaling element.

Identical reference symbols in the individual figures refer to identical or functionally corresponding parts.

Figure 1 shows a schematic furniture drive 1 with two motors 7 underneath a piece of furniture 2, which is also sketched schematically. The furniture drive 1 contains a control 6 and a power supply 4, which can also be arranged outside the furniture drive 1 as an external power supply 5. A hand control 3 is connected to the control 6 of the furniture drive 1. This connection can be either wired or wireless. The hand control 3 has buttons Sl ₅ S2, whereby two buttons are required for each motor 7 for an upward and a downward movement. The hand control 3 also has a locking device 30 with at least one first switching element 11, which is preferably arranged inside the hand control housing.

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The function of this switching element 11 is explained in more detail below in connection with Figures 2 and 3. The manual control 3 is also equipped with at least one signaling element 19.

Figure 2 shows an example of the manual control 3 in the form of a block diagram. The power supply for the manual control 3 is via the power supply 4, 5 from the furniture drive 1. Voltage adapters 8, 8' are arranged within the manual control 3, which provide the necessary voltage for one or more functional units of the manual control 3. A first supply line 9 connects the voltage adapter 8' to the signaling element 19 on the one hand and to the locking device 30 on the other, which preferably consists of a first and second switch 17, 18 and which, when switched on, connects the first supply line 9 to the buttons Sl, S2 via a switching line 21. By pressing one of the buttons Sl, S2, a relay 20 in the control 6 in the furniture drive 1 is activated, which switches on an associated motor, here the motor 7, with its load contact. In order to be able to switch on the motor 7 in the furniture drive 1 using the buttons S1, S2, the switches 17, 18 must be switched on. Their switching state is signaled by the signaling element 19, for example optically and/or acoustically. For this purpose, the switching element 11, preferably a sensor, is activated, the signal output of which simultaneously puts a first switching memory 13 and a second switching memory 14 into a storage state. The output signals of the switching memories 13, 14 are each forwarded to the first switch 17 and the second switch 18 via a first timing element 15 and a second timing element 16.

The first switching memory 13 is connected to the first timer 15 and the first switch 17, and the second switching memory 14 is connected to the second timer 16 and the second switch 18. The timers 15 and 16 switch the switches 17 and 18 on one after the other with a time delay. This time-delayed switching on is signaled by different intensity values of the signaling element 19, for example by different brightness levels. In a preferred embodiment, the signaling element 19 is a display.

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light, for example an LED, and indicates the locked state of the switches 17, 18 by lighting up. When the switches 17, 18 are operated, the brightness of the signaling element 19 jumps, preferably increasing abruptly. As soon as the switches 17, 18 are both switched on, the signaling element no longer lights up. This advantageously makes it extremely easy to check the function of the switches 17, 18 each time they are operated.

Figure 3 shows a preferred embodiment of the circuit of a hand control 3 according to the block diagram of Figure 2. In this preferred embodiment, the first switching element 11 is formed by a Hall sensor. This sensor is activated, for example, by means of a magnet applied to the hand control 3. The signal generated by the sensor is simultaneously forwarded to the first switching memory 13 and the second switching memory 14. The first switching memory 13 is connected to the first switch 17 via the first timing element 15, and the second switching memory 14 is connected to the second switch 18 via the second timing element 16. The two switches 17, 18 are preferably formed from semiconductor switches such as transistors. The supply voltage with which the relays 20 for the motor or motors 7 are activated is applied to the first supply line 9. The supply line 9 is connected to the first switch 17. The second switch 18 is connected to the first switch 17 and the second switch 18 in turn to the buttons Sl and S2. If both switches 17, 18 are now switched on, the supply voltage of the first supply line 9 is applied to the buttons Sl and S2, the actuation of which activates one of the relays 20.

The connection between the first switch 17 and the second switch 18 has an additional connection via a diode D1 and a resistor R4 shown in dashed lines to a current path in which the signaling element 19 is located. The signaling element 19 is connected to the first supply line 9 via a further resistor R2. The signaling element 19, which in this embodiment is a light-emitting diode, is connected with its other connection to ground via a resistor R3 and at the same time via

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BOEHMERT & BOEHMERT
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another diode D2 and a resistor R5 shown in dashed lines are connected to the switching line 21. The diodes D1 and D2 act as blocking diodes, which means that they prevent reactions on the switches 17 and 18 due to the state of the signaling element. As an alternative to the blocking diodes, the resistors R4 and R5 shown in dashed lines can also be used alone or in addition.

There are three cases in the function:

In the first case, the two switches 17 and 18 are not switched on. In this case, the connecting line between the signaling element 19 and the connection between the switches 17 and 18 is virtually potential-free. Thus, the signaling element 19 as a light-emitting diode is connected to ground via the resistor R3 and to the first supply line 9 via the resistor R2. The display element 19 lights up with a certain brightness value that is specified by the resistors R2, R3.

The second case is characterized by the fact that the first switch 17 is switched on, while the second switch 18 is not yet switched on due to the time delay of the second timer 16. In this case, the first switch 17 bridges the brightness-determining resistor R2 and thus the signaling element 19 is connected directly to the first supply line 9 via the connecting line to the connection between the switches 17 and 18 via the switched-on switch 17 and thus shines brighter.

In the third case, both switches 17 and 18 are switched on. The series resistor R2 of the signaling element 19 is thus bridged by the first switch 17 and at the same time the signaling element 19 is bridged by the switched on switch 18 so that this signaling element 19 no longer lights up. These three states are clearly indicated by the brightness states of the signaling element. This also makes it possible to check the function of the switches 17 and 18 at the same time. This checking and signaling of the various states is advantageously carried out with just one signaling element 19.

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The signaling element 19 can also be an acoustic signaling element, which additionally or solely characterizes the states through its pitch. A combination of light and acoustic signaling is also conceivable.

The time-delayed switching of the second switch 18 can additionally be advantageously and easily influenced by bridging its switching input from the timing element 16 and the connection between the switches 18 and 17 by a capacitor C1.

In a preferred embodiment, the timing elements 15, 16 each consist of a resistor-capacitor combination. Other embodiments are of course conceivable.

In this embodiment, the switching memories 13, 14 are implemented by integrated circuits, so-called flip-flops. Here, too, further variations are of course conceivable.

In this embodiment, the voltage adapter 8 for the first supply line consists of a so-called Zener diode and a series resistor R6.

Only the first switching element 11 is shown. Other variants are conceivable with a second switching element 12, which is actuated simultaneously or in succession with the first switching element 11. The design of these switching elements can be different. It is important that the actuation of the switching elements 11, 12 activates two time-delayed branches that activate two switches 17, 18, and that their switching states and function are simultaneously signaled by a signaling element 19.

The signaling of the intensity values of the signaling element 19 is shown in Figure 4. The time is plotted on the horizontal axis and the intensity on the vertical axis, with the reference numeral 23 designating a low intensity value and 24 a higher intensity value.

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If both switches 17 and 18 are blocked, a so-called first state 25 is signaled by the low intensity value 23. If the first switch 17 is switched on, an intensity jump 22 occurs at the signaling element 19 to a second intensity value 24. This is identified by a second state 26. As soon as the second switch 18 is switched on, the signaling element 19 is inactive, which is identified by a third state 27, which has the intensity value 0.

If the signaling element 19 signals the low intensity value in the blocked state, this shows that both switches 17 and 18 are functioning. If an intensity jump 22 is generated at the signaling element 19 after the switching elements 11, 12 are activated, this is a sign that the switches 17, 18 are functioning correctly. The switches 17, 18 are then switched on, which is signaled by the inactivity of the signaling element 19 and is designated in Figure 4 with a third state 27.

Actuating the switching element 11 again returns the locking device 30 to the locked state 25.

It is also possible that the switches Sl, S2 do not switch the relays 20 directly, but are connected to them via a semiconductor output or a wireless connection such as infrared or radio.

The signaling element 19 can also be a multi-coloured LED or an acoustic signalling device with different tone sequences. In these cases, the signalling element does not change the intensity to signal the states of the locking device, but rather a colour change or a tone sequence change.

In a further embodiment, two switching elements 11 and 12 are arranged spatially offset from one another, for example as Hall sensors, so that when they are actuated,

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This means that when an actuating magnet is moved across it, two signals are generated with a time delay. This means that the timers 15 and 16 can be omitted.

The movement must be carried out in a specific direction. This means that an unintentional actuation cannot lead to a switching process.

Furthermore, it is conceivable that switching memories 13, 14 (and possibly timing elements 15, 16) and the switches 17, 18 are arranged together in an integrated module.

In another embodiment, the electric motor-driven furniture drive has a disconnecting circuit for isolating the power supply from the mains during breaks in operation. In this case, the locking device and its functional components are supplied with electricity via a standby line.

D10218(H)

List of reference symbols

1 Furniture drive 2 Furniture 3 Manual operation 4 Power supply 5 External power supply 6 steering 7 engine 8.8' Voltage adjuster 9 first supply line 10 second supply line 11 first switching element 12 second switching element 13 first switching memory 14 second switching memory 15 first time element 16 second time element 17 first switch 18 second switch 19 Reporting element 20 relay 21 Switch line 22 Intensity jump 23 first intensity value 24 second intensity value 25 first state 26 second state 27 third state 30 Locking device Cl capacitor Dl-2 Diodes Rl-6
1 1 Resistances Sl-2

Claims (15)

1. Electromotive furniture drive with at least one drive motor ( 7 ), at least one manual control ( 3 ) which has function-triggering buttons ( 51 , 52 ), at least one switching element ( 11 , 12 ), at least one signaling element ( 19 ) and a locking device ( 30 ), characterized in that the locking device ( 30 ) contains a first switch ( 17 ) and a second switch ( 18 ), and that the signaling element ( 19 ) signals the correct function and the states of the locking device ( 30 ). 2. Electromotive furniture drive according to claim 1, characterized in that the locking device ( 30 ) is formed from two semiconductor switches connected in series. 3. Electromotive furniture drive according to claim 2, characterized in that the semiconductor switches are transistors. 4. Electromotive furniture drive according to one or more of claims 1 to 3, characterized in that at least one switching element ( 11 ) is provided for switching the locking device ( 30 ), which is connected to two switching memories ( 13 , 14 ), the output of the first switching memory ( 13 ) being connected to the first switch ( 17) via a first timing element (15 ) and the output of the second switching memory ( 14 ) being connected to the second switch ( 18 ) via a second timing element ( 16 ). 5. Electromotive furniture drive according to claim 4, characterized in that the timing elements ( 15 , 16 ) are each formed from a resistor-capacitor combination. 6. Electromotive furniture drive according to claim 4 or 5, characterized in that an additional time delay is formed by a capacitor (C1) connected to the input of the second switch ( 18 ) and its connection to the first switch ( 17 ). 7. Electromotive furniture drive according to one or more of claims 1 to 3, characterized in that two switching elements ( 11 , 12 ) are provided for switching the locking device ( 30 ), which are connected to two switching memories ( 13 , 14 ), the output of the first switching memory ( 13 ) being connected to the first switch ( 17 ) and the output of the second switching memory ( 14 ) being connected to the second switch ( 18 ). 8. Electromotive furniture drive according to one or more of claims 1 to 7, characterized in that the first switch ( 17 ) in the switched-on state, the second switch ( 18 ) not being switched on, causes a different intensity value or a different signal value of the signaling element ( 19 ) than in the switched-off state, and that in the switched-on state of both switches ( 17 , 18 ) the signaling element ( 19 ) is inactive. 9. Electromotive furniture drive according to claim 8, characterized in that the signaling element ( 19 ) is a light-emitting diode. 10. Electromotive furniture drive according to claim 9, characterized in that the signaling element ( 19 ) is connected to a first supply line ( 9 ) by a resistor (R2) and to a ground by a resistor (R3), the connection of the signaling element ( 19 ) to the resistor (R2) being connected to the connection of the first switch ( 17 ) to the second switch ( 18 ), and the connection of the signaling element ( 19 ) to the resistor (R3) being connected to the connection of the second switch ( 18 ), a switching line ( 21 ). 11. Electromotive furniture drive according to claim 10, characterized in that the connections of the signaling element ( 19 ) to the second switch holder ( 18 ) are each formed via a diode (D1, D2) and/or a resistor (R4, R5). 12. Electromotive furniture drive according to one or more of claims 1 to 9, characterized in that the signaling element ( 19 ) is a multi-color light-emitting diode and/or an acoustic signaling device. 13. Electromotive furniture drive according to one or more of claims 1 to 12, characterized in that the switching element ( 11 , 12 ) is a Hall sensor. 14. Electromotive furniture drive according to one or more of claims 1 to 13, characterized in that in each case a switching memory ( 13 , 14 ), a timing element ( 15 , 16 ) and a switch ( 17 , 18 ) or in each case a switching memory ( 13 , 14 ) and a switch ( 17 , 18 ) form a common module. 15. Electromotive furniture drive according to one or more of claims 1 to 14, characterized in that the electromotive furniture drive is provided with a disconnecting circuit for disconnecting the power supplies ( 4 , 5 ) from the mains during breaks in operation, the locking device ( 30 ) and its functional components being supplied with electricity via a standby line.