Technical Field

The invention relates to equipment for access control, especially an access to a market shopping area, the equipment being provided with a swing gate coupled with a drive unit and a control unit.

Background of the Invention

An access into a shopping area of a big shopping centre of a supermarket type is usually controlled by an equipment enabling persons only to enter inside. To return outside one has to go through a cash-desk section. Such an equipment for access control comprise a single- or double-side gate which opens automatically when a customer approaches the control point, no matter if he holds only a shopping basket or pushes a shopping cart. It is not possible to pass through the control point in an opposite direction as the gate strongly resists any such effort and it cannot be moved from inside the shopping area without being mechanically damaged. The barrier of the discussed type typically comprises a column carrying a gate, the swinging movement of which is controlled by a drive system activated by a signal from a sensor detecting movements of persons. The drive system automatically opens the barrier when anybody tries to enter the inside area and closes the barrier when no further persons pass by. The drive system comprises a subtle high-speed motor with a practically self-clamping clutch. The sensor usually comprises an electronic optical radar or a similar equipment. The equipment as such has to be sufficiently robust to prevent an illegal action, i.e. non-licensed passage from the shopping area outside. An equipment of the said type is described e.g. in the document WO 2008/000360. Current equipment preventing a passage in an undesired direction nevertheless do not allow a passage in an opposite direction even In an emergency case, like a fire, when for safety reasons it is necessary to evacuate all persons out of the shopping area in a relatively very short time. Such a state contravenes the European Community safety regulations which have been enforced to prevent serious casualties caused by resistivity of the existing barriers when somebody tried to pass during an emergency state. The demand to enable a pass when gently touched during a movement in the allowed direction and simultaneously presenting a resistance of up to 100 Nm to prevent an illegal breakthrough in the non-allowed direction cannot be technically achieved by the construction featuring only one action member, a high-speed motor and a high-ratio gear-box, giving high inertial energy at the shaft out. In known designs the demand on a limited force to overcome the barrier during danger satiations in shopping areas is solved by an additional clutch allowing for a slip due to a mechanically adjustable limit resistance. Such a solution does not allow for a new requirement of a resistance control according the actual position of the barrier gate, but its complicacy results in a high failure rate and corresponding high maintenance costs.

It is an object of the invention to create equipment featuring sufficient resistance against any pass through the gate in an illegal direction but in a case of emergency allowing any person to overcome the barrier when applying appropriate force and simultaneously eliminating any possibility of both a damage to the equipment and injury to people trying to escape from the area,

Disclosure and Object of the Invention

The foregoing objects are achieved and the present problems solved by equipment for access control, the equipment being provided with a barrier coupled with a drive unit and a control unit in accordance with the present invention, where the drive unit is provided with coaxially arranged direct-current motor and electromagnetic friction brake, the brake friction disk being coupled with a rotor of the motor. The said direct-current motor may have either inside or outside arranged rotor. Further in accordance with the present invention the electromagnetic friction brake is provided with a toroidal excitation coil arranged coaxially with the rotor of the direct-current motor. Still further in accordance with the invention the rotor of the direct-current motor is coupled with the brake friction disk by means of at least two pegs arranged in parallel with the friction disk axis, the friction disk having a shape of a toroid is traversable on the pegs in the axial direction. In a preferred embodiment the control unit is provided with electronic optic radar.

According the first aspect of the invention the equipment having a low-speed direct-current motor has sufficient moment for operation functions, without any cogging-effect, i.e. without moment pulses by low speed operation which are typical for applications with step motors. The friction brake provides for precise control of the barrier passive resistance up to the value of 100 Nm which can be adjusted in time and angle. The brake further provides for locking a working position by a residual magnetism due to remanence of the magnetic circuit material. The remanence of the magnetic circuit material minimizes energy consumption for a return of the bar into basic position. The equipment according the invention sensitively follows movement of persons passing by and by controlled action creates a passive resistance to illegal passing through. The construction of the equipment also offers minimal demands on energy while in stillstand.

Brief Description of the Drawings

The invention is further illustrated by way of examples presented in the accompanying drawings, where

Fig. 1 shows a principle arrangement of a drive system and

Fig. 2 presents an internal design of the drive system according Fig. 1 as shown in a sectional view in an a longitudinal direction

Description of Preferred Embodiments

Referring to Fig. 1 and Fig. 2 there is shown an equipment for access control provided with a drive system comprising a low-speed direct-current motor 1 and an electromagnetic friction brake 2, the motor 1 and the brake being in a mutually coaxial arrangement carried by a column 3. The drive system actuates a swinging barrier. Fig. 1 and Fig. 2 show only a part of the barrier which substantially has a shape of a rectangular frame 4. Usually the frame 4 carries a disk which from the in-coming side, towards approaching persons shows a white arrow in a blue field, while from the opposite side the disk shows a white stripe in a red field, which are commonly known traffic symbols of a directed way and forbidden way resp.

The shown embodiment applies a direct-current motor 1 with an outside rotor 5 and inside stator 6 mounted on a fixed shaft 7, the shaft 7 providing for an axis of the drive system. The rotor 5 seating in a first bearing 8 and a second bearing 9 is directly connected with the barrier frame 4. By means of a third bearing 10 the frame 4 is in a swing fit arranged at an extended part of the fixed shaft 7 or the column 3 as the case may be. The electromagnetic friction brake 2 has a toroidal excitation coil 13 arranged spaced apart from the direct-current motor 1 and coaxially with the outside rotor 5 of the d-c motor 1. A toroidal friction disk 12 of the electromagnetic brake 2 is positioned within the space between the rotor 5 and the excitation coil 13. The friction disk 12 is coupled with the rotor 5 of d-c motor 1 by means of three pegs 11 fixed to the body of the rotor 5. The pegs 11 are arranged coaxially with an axis of the friction disk 12 and the axis of the fixed shaft 7. The friction disk 12 is traversable along the pegs 11 in axial direction. At least two pegs 11 have to be applied, for a good transfer of a braking force just three pegs 11 are sufficient. Nevertheless even more pegs 11 can be used.

The drawings do not show the control unit. In the presented embodiment of the equipment the control unit is located in the column 3, just above the drive unit. The power supply wires both for the control and drive units are installed inside the column 3 and through the shaft 7 which is hollow. The control unit is provided with a sensor for detection of persons approaching the equipment. A preferred type of such a sensor is e.g. en electronic optic radar.

In an alternative embodiment the equipment may be provided even with a d-c motor with an inside arranged rotor. Such an inside rotor is coupled with a tube which carries the gate and simultaneously is coupled with the friction disk 12 of the electromagnetic brake 2.

The equipment is activated by a signal from the sensor. In response to the signal the electromagnetic brake 2 is demagnetized and the d-c motor 1 started. The friction brake 2 stops the rotor 5 and thus the gate movement in a predetermined position. Then the friction brake 2 power supply is switched-off, but the residual magnetism holds the gate in an open position as long as a passage of persons is detected. With no response from the sensor the gate returns to the original passage closing position, where it is again only due to the residual magnetism of the electromagnetic friction brake 2 magnetic circuit. As in the gate closed position no mechanical force is active, i.e. the gate is not coupled with any other mechanism, for opening the gate outwards from the shopping area it is necessary to overcome a friction moment between the friction disk 12 coupled with rotor 5 and the contact surface of the friction brake 2 fixed to the column 3. The friction moment is excited by an electric current flowing through the excitation coil 13 of the friction brake 2. This moment can be pre-set either by application of a magnetic material of required properties or by a value of magnetizing current of the excitation coil 13 or by both the said means. The stillstand position of the gate is secured by a remanence induction of the brake 2 magnetic circuit, thus without any further electric current consumption.

The above described equipment meets all safety regulations and simultaneously offers all function required from equipment of the kind.

The suitable direct-current motor 1 is described in the document WO 2012155868. The construction of the motor shows no moment variations irrespective to motor speed as is the case by step motors.

Industrial applications

The present invention is designed for application is shopping areas of the supermarket type.