EP0172597B1 - Security catch for vertically closing doors - Google Patents

Description

The present invention relates to a fall protection device for lifting doors, hatches, lattice doors and commercial doors with vertical or partially vertical opening and closing movements. As a result of tearing an accessory of the suspension device, such as a wire rope, a compensating spring, a chain and the like, a door which has been pulled up can fall, which can lead to a serious accident. The legal safety regulations in accordance with the trade regulations, building laws, occupational safety and traffic jam laws can be met by attaching systems that prevent the cable from falling if the cable is clamped or damaged, as well as in the event of spring breakage, the cable from which the door is attached, etc.

The present invention aims to provide suitable protection against such accidents.

The principle and function of the doors in question are described in the publication P 47 of the Dutch Trade Inspectorate and the Port Trade Inspectorate from October 1981: "Doors and movable grilles, construction and maintenance".

At least two separate steel cables or chains must be used to suspend vertically opening and closing doors. The cables are made of retracted, linked wire ropes and are constructed as prescribed in the standard NEN 3231: "Steel cables, parallel constructions for lifting and pulling devices".

The known fall protection devices, as shown on page 12 of the first-mentioned publication, have the disadvantage that the cables have to run in door rails which are provided with cutouts.

When the cable is taut, the spring-operated safety device runs up and down, whereas when the cable is no longer tensioned, squats press outwards, which jump into the recesses. According to the regulations, the distance between the cutouts is a maximum of 20 cm. So the heavy door can fall over 20 cm. In addition, a blocking of this device by clamping the spring or by jumping the cam out too slowly cannot be ruled out. Furthermore, this fuse is unsuitable for functioning if the spring breaks.

U.S. Patent 1 863 961 describes a fall arrest device in which the horizontally mounted axis, with the drum on which the holding cables of the door are wound, is provided at its end with a locking wheel without spring, which is connected by a lever to a button which is actuated by a Weight is pressed on a line to the holding cable. If the cable breaks, the button moves a pawl over the lever, which engages in the locking wheel, which locks the axle.

The fall arrest device according to the present invention is located in a housing which is fastened on one side or on both sides of the door opening, on the upper side of vertical guide rails to the wall or the portal construction, and in which there is a mounted axle on which one The drum is welded, on the circumferential surface of which a securing band is wound, and on which a locking wheel is also welded, and is characterized in that it is connected to a self-winding flat spiral spring which exerts a force which keeps the securing band wound while in secant form attached recesses in the circumference of this locking wheel fits a pawl from a lock holder, which is triggered by an electromagnet, and which blocks the rotation of the axle in one direction when the pawl engages in one of the recesses in the secant direction. This happens if a torsion spring breaks and if the cable is slack or torn.

According to the invention, a cable switch is connected to an electrical switch which, in the normal state, allows the current to flow to the electromagnet. The power supply is interrupted by the action of this button as a result of slackening or tearing of the cable.

To prevent spring breakage, a tilting mechanism is mounted on each spring, which is tilted by the force developed by the spring when it is being wound.

In the tilted state, an electrical switch is operated which allows the current to pass through.

If the spring tears or loosens, the spring is released, which eliminates the force that is supposed to keep the tilting mechanism in a tilted position.

This causes the tilting mechanism to return to the non-tilted position, which means that the switch is no longer actuated and therefore no longer allows current to pass through. According to the invention, an electromagnet is located in the above-mentioned housing above the ratchet wheel, which holds the pawl up. By connecting all the pushbuttons, tilting mechanisms and electromagnets in series on the pawl, the power of the electromagnet acting on the pawl will be eliminated in the event of a power interruption of any kind, so that the pawl engages in the ratchet wheel so that it is stopped immediately. This will block the drum.

The blocking for securing when the cable breaks is caused by the button above the switch, which switches off the current to the electromagnet mounted above the pawl, so that it is no longer his Exerts force because the circuit is interrupted by the button.

The ratchet wheel is permanently connected to the center of the axle and to the drum on which the securing tape is wound. The end of the security band running out of the housing is connected to the underside of the door.

If cables or springs break or are no longer tensioned due to any cause, but become slack, the current for the electromagnets is interrupted and the beginning movement of the door is immediately arrested by the securing band, so that the door cannot move downwards.

A downward movement of the door is only possible again when the cable or spring is taut, a closed circuit is created again and the pawl is thus brought back to neutral.

In the event of upward movement, the securing band is wound onto the drum as a result of the action of the self-winding flat spiral spring, which acts on the ratchet wheel which is welded onto the mounted axle. Reliable control of the correct functioning of the safety device is manually possible according to the invention by interrupting the circuit, which corresponds to the situation which occurs with cables that are not tightly tensioned, with cable breaks, spring breakage or slack springs. The door must then not be able to be pushed down in any way.

Visual control of correct functioning is possible by making sure that the visible part of the securing strap is constantly taut.

• Fig. 1 zeigt eine Sicherungsvorrichtung mit der Sperrklinke, die vom Elektromagneten fest gehalten wird.
• Fig. 2 zeigt diese Vorrichtung in blockiertem Zustand, bei Bruch einer Torsionsfeder.
• Fig. 3 zeigt diese Vorrichtung in blockiertem Zustand, bei Bruch eines oder mehrerer Haltekabel.

The invention is further explained with reference to the attached 3 drawings.

• Fig. 1 shows a safety device with the pawl, which is held firmly by the electromagnet.
• Fig. 2 shows this device in the blocked state, when a torsion spring breaks.
• Fig. 3 shows this device in a blocked state, if one or more holding cables break.

The following parts are shown in it;

• 1. is the housing.
• 2. is the drum.
• 3. is the securing tape.
• 4. is the ratchet wheel.
• 5. are the depressions in the outline of the ratchet wheel, in which the pawl 6 can engage.
• 7. is the coil spring.
• 8. is the axis.
• 9. is the pawl bracket.
• 10. is the electromagnet.
• 11. is the cable button.
• 12. is the tilt mechanism.
• 13. is a resilient handle.
• 14. is a lift cable of the door.
• 15 and 16 are electrical
• Circuit breaker.
• 17. is a torsion spring of the door.
• 18. is a transformer (220 - 24V.).

In the housing (1) there is a self-winding rotating drum (2) with a securing tape (3) wound on it.

The security band is attached to the underside of the door.

A ratchet wheel (4) with a self-winding spiral spring (7) is fastened to the drum (2) and is provided with secant-shaped depressions (5) on the circumference.

Above it is a pawl (6) which is held up by an electromagnet (10).

The pawl is fastened with a hinge joint in the pawl holder (9).

The electromagnet (10) is fed from a transformer 220/24 V (18). A cable button (11) is attached behind each lifting cable (14). In the case of normally tensioned cables, this button actuates an electrical switch (15) which allows the current to pass through.

Each torsion spring (17) attached in front of the door is coupled to a tilting mechanism (12).

When the spring is normally tensioned, this mechanism is tilted due to the torsional force of the spring and the electrical switch (16) is actuated, which in this position passes current.

If the electrical components are connected in series, the electromagnet (10) is actuated.

If the resilient pusher (13) is now pressed, the pawl on the electromagnet is lifted and held in this position. If one or more torsion springs (17) break, as shown in Fig. 2, the forces that held the tilt mechanism in the tilted position cease.

The mechanism returns to the neutral position, whereby the electrical switch (16) no longer allows current to pass through. As a result, the electromagnet (10) is no longer supplied with current and the pawl (6) can no longer be held up. Due to its own weight or a tension spring, the pawl quickly falls down and engages in the recesses (5) of the ratchet wheel (4).

As a result of the spring break, the ratchet wheel (4) is immediately locked and thus also the drum (2) attached to it with the securing band (3) which is attached to the bottom of the door. The door's downward movement stops immediately.

If one or more cables are torn (see Fig. 3), the cable buttons fold outwards through the installed springs and the switch (15) stops flowing. The circuit is then also interrupted here and the downward movement becomes the door immediately stopped in the manner described above.

If the door is blocked by the safety device, it can only be opened further, for example by lifting it with a forklift.

By engaging the pawl (6), the self-winding drum (2) can only turn to the left, which means that the door can only be moved upwards.

When this upward movement is stopped, the pawl immediately engages in the recess, which immediately brings the door back into the safe position.

A blocked door can only be closed by lifting the door a little and then pressing and holding the resilient handle (13) until the fork lift has lowered the door completely.

When the handle (13) is released, the pawl (6) immediately engages in the recess and the door is immediately brought to a safe standstill.

Normal function of the door is only possible again when the cause of the blockage has been removed (i.e. when new springs or cables are installed).

The drum with the belt can only turn when the lifting cables and springs are taut and the circuit is closed. As an example, it should be mentioned that a lifting door of approximately 6 m in height with a weight of 800 kg is secured by a device according to the invention, which consists of two housings according to the attached figures, with the interacting parts shown therein, a flat spiral spring which attacks on the ratchet wheel, consists of an approximately 12 m long band made of stainless steel in the stretched state. Other dimensions are of course possible.

For the calculation of forces, a door weight of 200 kg was assumed, the lifting being carried out by two springs.

After the calculation, the weight of the door can be increased to 400 kg. The shear stress in the recess of the ratchet wheel then becomes 25 N / mm ² + 40% = 35 N / mm ² , and it remains significantly below the permissible maximum value of 85 N / mm ² .

The surface pressure in the contact area of the pawl and the ratchet wheel then becomes 47 N / mm ² + 40% = 66 H / mm ² and this is also clearly below the maximum value of 200 N / mm ² .

The securing band has a tensile strength of 1571 kg. With a safety factor of 3.9, the permissible load is 400 kg.

With a door weight of 400 kg, if two springs are used, only 200 kg can be locked if one spring breaks. The electrical installation is carried out in accordance with the requirements of NEN 1010.

The switch is a closed contactor, which has a mechanically forced interruption switching function, as specified in VDE 0660, T 206 and VDE 0113, 1.E.C. 44.

The magnetic core is provided with a copper layer.

The device described is approved for this purpose by the General Directorate of the Labor Inspectorate under file number No.AI-2981. The details described above represent examples according to the invention, but this is not restricted.

Claims (3)

1. A safety device for suspendings of lifting doors, hatches, gates and similar industrial doors with a vertical or partially vertical reciprocating movement for opening and closing, being positioned at the upper side of vertical guiding rails, each comprising a shaft (8) in a bearing, upon which shaft a barrel (2) is welded, which has a safety band (3) wound around its circumferential surface, and upon which further a ratchet wheel (4) is welded, characterized in that said ratchet wheel (4) is connected to a self-winding flat coiled spring (7), which executes a force to keep said safety band (3) in its wound-up position, whereas in the notch (5) at the circumference of said ratchet wheel (4) a locking pawl (6) will seize, skidding the rotation of the shaft (8) in the bearing in one direction, if an electromagnet (10) does no longer keep said locking pawl (6) outside of said notch (5), caused by the motion of a cable tracer (11) or of a tracer stylus (12) at the spring, which results in an instantaneous cut-out of the electrical circuit.

2. A device according to claim 1, characterized in that the electrical circuit of the electromagnet (10) is provided with switches (15) and (16), which in the normal position of the cables (14) or with strained springs (17) allow an uninterrupted current, but which in case of an abnormal position of the tracer-stylus (12) (Kipp-switch) or of the cable tracer (11) will interrupt the current.

3. A device according to claim 1, characterized in that said device consists of a housing (1) with the shaft (8) in the bearing therein, having the barrel (2) attached to it in a centric position, with a safety band (3) partially wound around its circumferential surface, and having a ratchet wheel (4) with a self-winding flat coiled spring (7) also attached in a centric position, said ratchet wheel (4) having notches (5) which are directed in a secant pattern, into which a locking pawl (6) kept with a hinge joint in the pawl seating (9) can seize, if an electromagnet (10) is no longer excited, caused by a break of the current circuit, effected by tracers (11) laid at the cable (14), if the cables condition is such that it is no longer tightly strained.

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