Vertical roller door

Abstract

 An improved rolling gate (1), is provided with a DC electric motor (25) at a very low voltage, said motor is powered by an accumulator battery (21) associated to a battery charger (20) which can be connected to the 220 V power grid. In this way the gate (1) can be driven independently of the presence of the power grid voltage and the electric system (9) is more economical since it does not require the expensive protective means needed for the corresponding electric systems which work with 380 V current.

Description

[0001] The present invention discloses an improved rolling gate.

[0002] The above mentioned gates are known, for instance, from the Italian patent no.1246178. Said gates substantially comprise lifting means which drive a door formed by a plurality of panels linked together by hinges. The door slides vertically along side tracks which can be fixed to the gate opening. The lifting means comprise a mechanical group, a hydraulic system and an electric system. The mechanical group is of the rope and pulley type and it drives directly the door. The hydraulic system comprises a hydraulic pump which drives a hydraulic cylinder which is the actuator of the mechanical group. The electric system comprises a feeding electric circuit and a control electric circuit, said circuits drive a 380 V three-phase electric motor which drives the hydraulic pump.

[0003] These types of gates are not sufficiently reliable and are not safe since, in case the power supply stops (for instance, because of a fire), said gates cannot be opened as fast as needed or they cannot be opened at all since they could remain locked. Further, the electric system needed for the proper operation of said gates affects significantly the manufacturing, installation and maintenance costs since said electric system has to be realised, installed, assembled and managed so as to reduce to the minimum level the danger of electric shocks for the installers, the operators and for the maintenance people.

[0004] The purpose of the present invention is to provide a gate which overcomes simultaneously the above disadvantages, and to provide a rolling gate which can work independently of the presence of the power grid voltage and which is, further, more economical than the traditional gates of the same type.

[0005] Said purposes are achieved by a rolling gate according to claim 1, which is taken as reference.

[0006] By powering the electric motor through an accumulator battery rechargeable by means of a battery charger, the rolling gate can be driven even in case of power grid failures. The rolling gate according to the invention is therefore much more reliable than the corresponding traditional gates. Further, the use of very low voltages reduces significantly the manufacturing, assembly and maintenance costs of the electric system since the electric system is much simpler since it is no longer necessary to provide the electric system with specific means and/or features to protect the user of the gate from electric shocks. The cost reduction is such that it largely compensates the need to integrate the accumulator battery and the battery charger in the electric system.

[0007] Said features shall be more evident from the description relative to two preferred embodiments of the invention; it is understood that said embodiments are just non limiting examples of the invention.

[0008] Figure 1 shows schematically a rolling gate according to the invention.

[0009] Figure 2 shows schematically and partially the drive means of a rolling gate, according to the invention, in a first embodiment.

[0010] Figure 3 shows schematically and partially the drive means of a rolling gate, according to the invention, in a second embodiment.

[0011] With reference to the above figures and in particular to Figures 1 and 2, the rolling gate, improved according to the invention, comprises, besides the rolling gate generally indicated by numeral 1, drive means, generally indicated by numeral 2. The drive means 2 drive the door 3 of the gate 1, said door is formed by a plurality of panels 4 linked together by hinges 5. The door 3 can slide vertically along the side tracks 6 which can be fixed to the gate opening (not shown) wherein the gate has to be installed. The drive means 2 comprise a mechanical group 7, a hydraulic system 8 and an electric system 9. The mechanical group 7 is of the type provided with ropes and pulleys and said group operates directly on the door 3 in order to drive said door, i.e. in order to lift or lower said door. The mechanical group 7 is preferably realised according to the technical details disclosed by said Italian patent herein indicated as reference. The hydraulic system 8 substantially comprises a liquid (oil) storage tank 10, a filter 11, at least a hydraulic pump 12, a nonreturn valve 13, a maximum pressure valve 14, a relief solenoid valve 15, a constant flow valve 16, and at least one hydraulic cylinder 17 to drive the mechanical group 7. As shown in Figure 2, the components of the hydraulic system 8 are hydraulically connected and positioned in such a way that the pump 12 drives the cylinder 17. The electric system 9 comprises an electric circuit to power the motor generally indicated by numeral 18 and shown with a thick line and an electric control system generally indicated by numeral 19 and shown with a thin line.

[0012] The electric circuit 18, which powers the motor, substantially comprises: a battery charger 20, at least one accumulator battery 21, a fuse 22, a battery switch 23, a relay 24 and a motor 25 which drives the hydraulic pump 12 which is mechanically connected to said motor.

[0013] As shown in Figure 2, the electric connections among the components of the electric circuit 18, which powers the motor, are realised to guarantee the power supply and therefore the operation of the motor 25. In the example, two accumulator batteries 21 are provided in order to increase the reliability, said batteries are connected in parallel so as to avoid the risk that one of the batteries is short circuited. The electric motor and the accumulator batteries 21 are of the very low voltage type (preferably 12 V direct current), the battery charger 20 can be connected to the alternate current power grid, preferably 220 V monophase current. The battery charger 20 is of the stabilised type, again in order to increase the reliability. Further, in the shown example, the electric circuit 18, which powers the motor, is connected to a second relay 26 and at least to an emergency light 27, said relay and said light are activated by power grid failures. The electric control circuit 19 substantially comprises a push-button 28 to lift or lower the gate, a pilot light 29, a fuse 30 and the already mentioned motor relay 24 which is the connection element between the power feeding electric circuit 18 and the electric control circuit 19.

[0014] The drive means shown in Figure 3 are different from the ones shown in Figure 2 since they are structured so as to comprise the mechanical groups 7 belonging to a plurality of rolling gates 1, which can then be controlled by a single hydraulic system 8A and by a single electric system 9A. In Figure 3 the elements corresponding to the elements of Figure 2 are indicated with the same numerals. In summary: the hydraulic system 8A is different from the system 8 since it comprises a plurality of hydraulic cylinders 17 and relative stop solenoid valves 31 (two in this example). The electric system 9A is different from the electric system 9 since, substantially, the electric control circuit comprises a number of push-buttons 28 (to lift or lower the gate) equal to the number of cylinders 17 (two in this example).

[0015] The opening of the gate 1 is obtained by starting up the motor 25 and therefore by putting the hydraulic system 8 under pressure. The closing of the gate is instead realised by exploiting the force of gravity and by adjusting the descent speed through the oil flow in the hydraulic system by means of the constant flow valve 16. As a consequence, the motor 25 works only for about a quarter of the total time that it takes to open the gate, pass through the gate and close the gate. Besides, the use of the gate is generally sporadic, since the opening, passage through and closing operations are very seldom done in tight sequence. Therefore there is a further reduction in the use of the power which generates the hydraulic pressure, with a consequent possible simplification of the circuits and thus the reduction of the relative costs.

[0016] Additionally, low capacity accumulator batteries (buffer batteries) can be used, wherein said batteries can be recharged by a low consumption battery charger, which can work (as seen before) with simple monophase current with further cost reductions. Just as an example, a rolling gate normally considered heavy, i.e. having a door passage of 4 x 4.5 meters, requires just a 500 Watt motor, which is powered by a 45 AH accumulator battery and which guarantees at least 20 full opening and closing cycles, even consecutive (without pauses), without having to recharge the battery. Always as an example, the transformer of the battery charger can just be a 30 VA transformer, with a 220 V monophase current consumption of very few Watt.

[0017] The use of the drive means, in the case of the gates, is usually so sporadic that said drive means 2A can be used for more than one gate and/or for other hydraulic devices which could be relatively close: for instance electro-hydraulic ramps (a typical case is a freight loading bay, wherein there are a rolling gate and a hydraulic ramp below). In such case the chosen device is driven by opening the hydraulic force flow only towards said device, by opening, for instance, a flow stop solenoid valve. For instance, the drive means 2 could have the structure shown in Figure 2, wherein the motor 25 drives only one gate 1, therefore there is only one relief solenoid valve 15, which closes the gate at a descent speed defined through the adjustment of the constant flow valve 16.

[0018] Another solution can be indicated by the drive means shown in Figure 3, wherein the motor 25 drives two hydraulic cylinders 17 and therefore two gates; in such a configuration it is possible to select one of the gates by opening the corresponding solenoid valve 31 for the complete stop of the flow in both directions. In order to close the gates, it is necessary to open simultaneously one of the stop solenoid valve 31, the relief solenoid valve 15, while the closing or descent speed is adjusted through the constant flow valve 16.

[0019] Another solution provides, in addition to the stop solenoid valve 31, as many more stop solenoid valves as the loading ramps and/or the rolling gates and/or the other hydraulic devices to be driven by the same drive means 2.

Claims

1. Improved rolling gate comprising drive means (2, 2A) which drive the door (3) formed by a plurality of panels (4) linked together by hinges (5), said door (3) sliding vertically along the side tracks (6) which can be fixed to the gate opening, wherein said drive means (2, 2A) comprise a mechanical group (7), a hydraulic system (8, 8A) and an electric system (9, 9A), wherein:

- said mechanical group (7) is of the rope and pulley type and drives directly the door (3) so as to lift and lower said door,

- said hydraulic system (8, 8A) comprises at least a hydraulic pump (12) which drives at least one hydraulic cylinder (17) which drives the mechanical group (7),

- said electric system (9, 9A) comprises an electric circuit (18), which powers the motor, and an electric control circuit (19, 19A), said circuits drive at least one electric motor (25) which drives the hydraulic pump (12),
characterised in that the electric motor (25) is of the very low voltage type and is powered by at least one accumulator battery (21) connected to a battery charger (20) which can be connected to the power grid.

2. Improved rolling gate as claimed in claim 1, characterised in that the electric motor (25) is a DC motor and in that the battery charger (20) can be connected to a low voltage power grid.

3. Improved rolling gate as claimed in claim 2, characterised in that the electric motor (25), the accumulator battery (21) are of the very low voltage type and in that the battery charger (20) is of the type which can be connected to a power grid.

4. Improved rolling gate as claimed in claim 1, characterised in that the battery charger (20) is of the stabilised type.

5. Improved rolling gate as claimed in claim 1, characterised by comprising two accumulator batteries (21) in a parallel arrangement.

6. Improved rolling gate as claimed in claim 1, characterised in that the electric circuit (18) which powers the motor is associated to a relay (24) and to at least one emergency light (27), said relay and said light are activated in case of a power grid failure.

7. Improved rolling gate as claimed in claim 1, characterised in that the drive means (2, 2A), the electric system (9, 9A) and the hydraulic system (8, 8A) of a gate comprise the mechanical groups (7) of a plurality of rolling gates (1).

Drawing