GB2049029A

GB2049029A - Control for the Drive of a Door

Info

Publication number: GB2049029A
Application number: GB8012647A
Authority: GB
Original assignee: IFE GmbH
Current assignee: IFE GmbH
Priority date: 1979-04-18
Filing date: 1980-04-17
Publication date: 1980-12-17
Also published as: ES490648A0; ES8103255A1; GB2049029B; DE2924884C2; IT1141917B; FR2454506B1; IT8021417A0; FR2454506A1; ATA291579A; DE2924884A1; AT359548B

Abstract

Control for the drive of a door, which reduces the maximum closing force acting on the door panel, in a predetermined safety region of the path of movement of the door panel, the safety region terminating at a distance from the closed position of the door panel. The distance of the safety region from the closed position of the door panel may fall within the region of elastic deformation of the door seal. If the control serves for a hydraulic or pneumatic drive 1 for doors, which is supplied with a pressure medium by way of a supply line, then pressure switches 9, 10, 11 are provided, which measure the pressure in the driving cylinder and on passing through the safety region, block the supply line when a predetermined upper limit pressure is exceeded and open the supply line when cylinder pressure is below a lower limit pressure. An electric motor drive may alternatively be used. <IMAGE>

Description

SPECIFICATION Control for the Drive of a Door In drives for doors, a high number of measures are known, which are intended to eliminate the risk of people and objects being trapped by the door during the closing movement. The presence of people or objects in the door-closing area is ascertained by means of suitable sensors and the latter emit commands for the continuation of the door movement.

The maximum forces occuring in the driving cylinders of the door-closing device are determined by the product of the maximum available pressure of the driving means times the piston surface. If these forces were to act on the door, this would lead to inadmissibly high acceleration of the door during the closing movement and thus to slamming of the door.

Therefore, restrictor members are incorporated in the air-supply line, which members limit the volume of air passing therethrough and thus limit the closing movement of the door. In the case of an unrestricted closing operation, a substantially smaller air pressure therefore acts on the cylinder surface than in front of the restriction point. The full available pressure of the drive means builds up in the pressure cylinder solely in the region of the final closed position, when the movement of the door is reduced by entering the door seal and locking mechanism.

Some know measures are, by way of example, initiating the reversing movement of the door, stopping the movement of the door with simultaneous cancellation of the closing force respectively for a pre-determined time interval etc., in order to acquire time to remove the obstacle from the path of movement.

When running means of transport for large numbers of people, experience has shown that measures of this type serve to delay the clearance of people at the stations, in that passengers unknowingly or knowingly prevent the closing movement of the doors, thus delay the final closure of the doors and consequently impede the flow of transport. Therefore, many managements require protective systems, which solely limit the maximum driving forces occuring in the closing direction, if an object is trapped and in particular so that towards the end of the closing movement, smaller forces than at the beginning of the closing movement may occur.

In the case of pneumatic drives for doors, driving cylinders with stepped pistons were already used for this purpose, in which towards the end of the closing movement, for the driving force, only a smaller cylinder piston surface comes into action and thus correspondingly lesser driving forces come into action.

One essential drawback of this construction is that the surfaces available for damping the end positions of the driving cylinder are reduced and thus become less effective. It is a particular drawback that shortly before reaching the final closed position, in which according to experience greater closing forces are required for insertion in the door-locking mechanism and compressing the sealing members, these forces can no longer be applied by the closing cylinder.

The invention relates to a control for pneumatic, hydraulic or electrical drives, in which, over a portion of the stroke, the maximum force coming to act on the door panels is reduced (safety region). Appropriately, this restriction is effective solely in a region of approximately 100--200mm before reaching the final closed position, but is cancelled shortly before reaching the latter (closing region), in order to allow the full closing force to act for the insertion of the door into the locking mechanism and the compression of the door seals. There is no risk of an object being trapped in the closing region, since this region is protected by the flexibility of the door seals.

In the case of pneumatic or hydraulic drives fordoors, a pressure control device is provided, which breaks or interrupts the supply of air to the driving cylinder by way of valves or produces a connection between the driving cylinder and the ambient air and thus limits the pressure acting in the driving cylinder to between an upper and lowerpressure level. The valves may be controlled by pressure sensors, which are actuated as a function of the pressure acting in the driving cylinder. A range switch monitors the travel of the driving cylinder or the movement of the door and causes the pressure limitation to be effective solely in a pre-determined part of the movement of the door.

In the case of electrical drives for doors, according to the invention, the maximum driving torque to be applied by the drive is reduced to a pre-determined value during part of the movement of the door.

Accordingly, the invention relates to a control for the drive of doors, which reduces the maximum closing force acting on the door panel in a pre-determined safety region of the path of movement of the door panel is characterised by the fact that the safety region terminates at a distance from the closed position of the door panel (closing-region). This distance should preferably fall within the resilient region of deformation of the door seal. In this way, any injury to people or damage to objects is reliably prevented, if the pressure in the working cylinder increases to the value of the pressure in the supply line.

In the case of controls for hydraulic or pneumatic drives for doors, which are supplied with a pressure medium by way of a supply line, pressure switches are frequently provided, which measure the pressure in the driving cylinder and when passing through the safety region, block the supply line when a pre-determined upper limit pressure is exceeded or open the supply line when a lower limit pressure is not reached.

In a preferred embodiment, a further pressure sensor is provided, which opens a pressure medium outlet pipe, when the pressure in the driving cylinder is higher than the upper limit pressure, when entering the safety region.

According to the invention, a control for electric motor drives for doors is constructed so that on passing through the safety region, the driving torque is reduced to a pre-determined value, for example by means of a slipping clutch which is brought into action temporarily, by reducing the main current or the e.m.f. of the motor and the like.

Two embodiments of the object of the invention are illustrated diagrammatically in the drawings. Figure 1 is a diagram of the control according to the invention for a pneumatic drive for doors, Figures 2, 3 and 4 are diagrams of the pressure distribution in the driving cylinder during the closing movement of the door panel and Figure 5 shows the control of an electric motor drive for doors.

The driving cylinder 1 is connected on the closing side 1s by way of a line, a quick-acting outlet valve 2s, a restrictor non-return valve 3s and an electropneumatic valve 4s to the pressure medium container 5. In a similar manner, the opening side 16 is connected by way of the quickacting vent valve 26, the adjustable restrictor non-return valve 36 and the electro-pneumatic valve 46 alternately to the pressure medium container 5 or to an outlet line. The valves 4s, 46 are operated by means of the switches 6s, 66.

The vent line leaving the valve 4s is closed by a plug 8 and a suitable vent valve 7s is provided, which is likewise controlled electro-magnetically and either connects the closing side 1s of the driving cylinder 1 to a vent line or blocks this line.

Furthermore, three pressure switches 9 to 11 are provided, which are acted upon by the pressure in the driving cylinder 1 on the closing side is and are switched respectively when one of three pressure levels p1, p2, p3 is passed, as will be described hereafter in conjunction with Figures 2, 3 and 4.

The current for the valves 4s and 7s is supplied by way of a relay 12, which is in turn connected in series with a range switch 1 3. This range switch is actuated by means of a control rail 14, which carries out a movement dependent on the movement of the door panel and determines the safety region.

In the diagrams of Figures 2, 3 and 4, the door movement s is plotted on the x-axis and the pressure in the driving cylinder on the y-axis.

Positions 21 to 30 correspond to the positions of the door during the closing operation. Position 21 corresponds to the completely open position of the door and position 29 to the completely closed position of the door. The safety region is illustrated by the line A-B. Below the x-axis, the switching state of the electro-pneumatic valves 4s and 7s is illustrated.

Figure 2 shows the pressure curve in the driving cylinder during a closing operation, in which there are no obstacles in the course of the movement of the door.

For closing the door, the switch 6s is actuated and thus compressed air is supplied to the door cylinder by way of the electropneumatic valve 4s and the restrictor 3s. The pressure on the closing side of the cylinder increases, the door is accelerated in the closing direction.

Approximately from position 22, the movement of the door takes place regularly, the pressure in the cylinder has dropped to the level Pst (P stationary). Approximately from position 28, the sealing members of the door increase the resistance to movement, the movement of the door is slowed down, the door travels at a reduced speed into the final locked position, The sealing strips of the door are pressed against each other (position 29). During the entire closing movement, the electro-pneumatic valves 4s and 7s are activated.

On passing through the safety region A-B, the pressure level in the cylinder is always below a preselected level p1.

A closing movement will now be described, during which the movement of the door is prevented (Figure 3).

Up to position 23, the closing movement takes place unhindered and assumes the same shape as in Figure 2. From position 23, the movement of the door is now prevented. The pressure in the closing direction increases to the pressure p6 in the container 5. In position A, the safety region is reached, the range switch 13 is closed by the control rail 14, the pressure in the supply line is above the pressure level p3. Accordingly, all three pressure switches 9, 10 and 11 are activated, the relay 1 2 responds.The circuit of the relay 12 is connected by the switches 9 and 10 to earth e10 and by the relay 12 to earth eft2. The vent valve 4s is de-energised, the supply to the cylinder from the container 5 is interrupted. The vent valve 7s is simultaneously de-energised and initiates the venting of the cylinder until the pressure switch 11 is de-energised on dropping below the pressure level p3. The relay 12 remains activated, since the relay circuit is still connected to the earth e10 by way of the switches 9 and 10. Thus, the vent valve 7s is once more activated and venting of the cylinder is interrupted (position 24).

The door now moves further in the closing direction, the air in the closing side of the cylinder and in the supply line expands until the pressure has dropped to the pressure level p, (position 25).

The pressure switch 9 and thus the relay 12 are de-energised, the valve 4s is activated and thus the cylinder is once more supplied with compressed air from the container 5. If, in the course of the further closing movement, the movement of the door is once more impeded (position 26), the pressure in the cylinder once more increases. On reaching the pressure level p2 (position 27), the pressure switch 10 and relay 12 once more respond, the valve 4s is de-energised and the supply of air from the container 5 is once more interrupted. On reaching the end of the safety region B, the range switch 13 is opened, the relay 12 is de-energised, the valve 4s responds and the cylinder is once more supplied with air from the container 5.If the movement of the door is impeded solely after entering the safety region A-B (position 30 in Figure 4), then the pressure in the driving cylinder increases from p,, to the value p2. The switches 9, 10 connect the circuit for the relay 12 to the earth e10, so that the valve 7s remains excited and the valve 4s is deenergised. Thus, the continued flow of pressure medium from the container 5 into the driving cylinder is blocked, the air located on the closing side Is and in the lines expands until the pressure level p, is reached. The pressure switch 9 and thus the relay 12 are de-energised, the valve 4s is activated and thus the cylinder is once more supplied with compressed air from the container 5. The further pressure curve corresponds approximately to that of Figure 2 on entering the final closed position.

The aforedescribed embodiment for a pneumatic drive for doors predominantly uses members such as are provided in standard door controls. It is also possible to construct a control for the same function with only two electropneumatic valves, which are controlled by a pressure regulator.

The embodiment illustrated in Figure 5 of an electrical drive for doors according to the invention, is described hereafter. As is known, various drive motors are used in drives for doors.

Both d.c. as well as a.c. power supplies are used for supplying current. The present embodiment provides a blockable d.c. shunt-wound motor as the drive motor, which is supplied with current from an a.c. power supply by way of a thyristor rectifier.

The d.c. shunt-wound motor 31 is connected by way of the thyristor rectifier 35 to the a.c.

power supply 37. The two-way rectifier 33 supplies the excitation current for the excitation coil 32. If the door-closing contact 38s is closed, then the excitation coil 32 is supplied with current by way of the two-way rectifier 33 in the flow direction is. The pulse transmitter 36 supplies firing pulses, which completely control the thyristor rectifier 35. The motor 31 supplies its full-load torque in the direction of rotation s. On passing through the safety region, the range switch 39 is actuated by way of the contact rail 40. The firing pulses of the pulse transmitter 36 are emitted with a delay relative to the phase relationship of the a.c. power supply, the flow of current is reduced by the rotor of the motor 31 and thus the motor torque is reduced.If the dooropening contact 386 is actuated, the excitation coil 32 is supplied with current in the flow direction 16, the pulse transmitter 36 supplies firing pulses, which completely control the thyristor rectifier 35.

The motor 31 operates with full-load torque, but in the direction of rotation 6.

The control for the motor may be replaced by a slipping clutch, which comes into action on passing through the safety region and limits the closing force in this region. Outside this region, the clutch is locked, so that it can transmit the full torque of the motor.

The invention is described by means of simple controls. The embodiment illustrated in Figure 1 uses commercially available parts'which have already been used in door controls. However, it is also possible to use members which have been adapted to the invention. For example, the valves 4s and 7s could be replaced by a single multi-way valve and the like.

Claims

1. Control for the drive of a door, which is adapted to reduce the maximum closing force acting on the door panel in a pre-determined safety region of the path of movement of the door panel, which safety region terminates at a distance from the closed position of the door panel.

2. Control according to claim 1, wherein the distance of the safety region from the closed position of the door panel falls within the resilient region of deformation of a door seal.

3. Control for a hydraulic or pneumatic drive for doors, which is supplied with pressure medium by way of a supply line, according to claim 1, wherein pressure switches are provided, which measure the pressure in the driving cylinder and on passing through the safety region block the supply line when a predetermined upper limit pressure is exceeded and open the supply line when a lower limit pressure in not reached.

4. Control according to claim 3, wherein a further pressure switch is provided, which opens a pressure medium outlet pipe when the pressure in the driving cylinder is higher than the upper limit pressure when entering the safety region.

5. Control according to claim 1, for electric motor drives for doors, wherein when passing through the safety region, the driving torque is reduced to a predetermined value for example by means of a slipping clutch which is actuated temporarily, by reducing the main current or e.m.f.

of the motor and the like.

6. Control for the drive of a door, substantially as hereindescribed with reference to and as illustrated in the accompanying drawings.