Winch for various shutters used for evacuation of smoke and ventilation purposes
BACKGROUND OF THE INVENTION 
     It is already known to use winches for manually or automatically opening any type of shutters placed on roofs or on facades of buildings for the evacuation of smoke or for ventilation purposes, these shutters being particularly provided at the top of staircases, elevator wells and ducts of any sort which are found in domestic, commercial or industrial buildings. The shutters permit, when closed, to protect the staircases and other ducts against bad weather, and, when open, to ventilate the premises, especially when the weather is hot. 
     Moreover, these shutters or smoke outlets should open instantaneously in case of a discharge of smoke or noxious gases in order to avoid their spreading throughout the building. 
     The smoke outlets are provided with spring devices tending to open them, and they are kept closed by means of a releasable locking mechanism, such as a mechanical or electromagnetic lock, a thermal fuse or the winch operating the smoke outlets for ventilation purposes. 
     But all such mechanisms do not accomplish all the functions required by the new safety regulations. 
     The present invention remedies this disadvantage by providing a winch which can be operated manually or with the aid of a small motor, the winch having a drum on which is wound the control cable of the smoke outlet, and which is subjected to the control of radial electromagnetic release means having multiple blocking positions providing an immediate response for an instantaneous automatic opening of the smoke exhaust outlets or vents. 
     SUMMARY OF THE INVENTION 
     According to the invention, the winch for the smoke outlet comprises a cabinet or enclosure of a rectangular parallelepiped shape, in which is mounted a casing containing a shaft for rotation of a drum around which is wound a cable for controlling the opening and closing of the shutter, this drum being connected by a train of pinions to an actuation member in the form, for example, of a crank; moreover, one of the pinions can be blocked by radial electromagnetic release means with multiple blocking positions, the electrical supply of which is controlled by a control circuit comprising two switches and a fist-operated switch, and the drum is also blocked via a ratchet wheel cooperating with a catch including a rod operated by an electromagnet controlled by one of the two switches and by the fist-operated switch through a contactor or relay. 
     According to another feature of the invention, an electric motor is provided for rotating the drum in order to rewind the cable of the smoke outlet, said electric motor being supplied under control of an electric circuit independent of the control circuit of the radial electromagnetic release means. 
     Various other features of the invention will become more apparent from the reading of the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention are shown by way of non limitative examples in the accompanying drawings in which: 
     FIG. 1 is a partially broken and cut away front view of a winch for controlling a smoke exhaust outlet according to the invention; 
     FIG. 2 is a cross section view taken along line II--II of FIG. 1; 
     FIG. 3 is an electrical circuit diagramm for explaining the connection of the winch. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As illustrated at FIG. 1, a winch used for actuating a smoke exhaust outlet is formed of a cabinet or enclosure 1 having a rectangular parallelepiped shape, and in which is mounted by means of screws or bolts 2 a casing 3 including in one side 3a a bearing 4 rotatably supporting a shaft 5. The front portion of the shaft 5 rotates in a bearing 6 fixed in a cover 7 of the cabinet or enclosure 1, the cover 7 being also maintained by the screws or bolts 2. 
     The shaft 5 supports a drum 8 which can rotate with the shaft 5. 
     A pinion 9 rigidly connected to the drum 8 and to the shaft 5 co-acts with a ratchet wheel 10 to which it is operatively connected. 
     Above the pinion 9 and meshing therewith there is mounted a pinion 11 integral with a shaft 111 rotatably supported by a bearing member 110 in the cover 7 of the casing 3 at one of its ends, and by a ball-bearing 12 at its other end. 
     Finally, the pinion 11 meshes with a pinion 13 mounted on a shaft 14 of a radial electromagnetic locking and release means 15. 
     The shaft 14 of the locking and release means 15 has an outer end provided with a square socket 16 which projects through the cover 7. 
     The top 1a of the cabinet or enclosure 1 carries two push-buttons 17, 18 for the control of switches. 
     As can be seen in FIG. 1, the ratchet wheel 10 co-acts with a rod 20 which forms a governor weight. The rod 20 is guided in a housing 21 fixed to the cabinet 1 and having at its upper portion an electromagnet 22 the winding of which is operative to lift the rod 20 since the rod 20 ends into an electromagnetic armature (not shown) included in the electromagnet 22. 
     Electrical power is supplied to the electromagnet 22 as well as to the electromagnetic locking and release means 15 through conductors 24, 25 via the switches controlled by the push-buttons 17, 18 and by an over-ride fist-operated device 28. 
     The end of a cable 8a controlling the opening and closing of the smoke exhaust outlet is attached to the drum 8, this cable extending through an opening 30 formed in the cabinet 1 and an opening 31 formed in the casing 3. Return pulleys (not shown) are provided for correctly guiding the cable. 
     As is shown in the electrical schematic of FIG. 3, when the push-button 17 is pressed, electrical supply to the electromagnet 22 is cut off. Thus, the rod 20 moves downwardly to the position shown in FIG. 1 on the ratchet wheel 10, but the rod 20 is free in its movements. 
     Simultaneously, a contactor or relay 33 opens and cuts off the supply of electrical current to the radial electromagnetic release means 15. At that moment, the drum 8 is free since the pinion 13 can rotate freely, and the cable can be then either unwound from or rewound on the drum 8 in order to open or close the smoke outlet. 
     For manual control, a crank 11b is mounted on the end of the shaft 111 of the pinion 11, the pinion shaft 111 having a square opening or socket 11a for receiving the end of the crank. The crank can also be coupled to the socket 16 of the shaft 14 of the pinion 13. 
     The crank can be replaced by an independently controlled electric motor, if so desired. In this case, the electric motor, as shown at 32 at FIG. 1, is suitably disposed inside the cabinet or enclosure 1 and the shaft 32a of the electric motor is coupled to the other end of the shaft 111 of the pinion 11. 
     When the cable is rewound on the drum 8 and if the push-button 18 is pressed, a switch 118 (FIG. 3) is closed and the electromagnet 22 is therefore activated. The rod 20 is raised, and the ratchet wheel 10 is thus disengaged but, at the same time, the radial electromagnetic locking and release means 15 is activated such as to lock the pinion 13 and the pinions 11 and 9. 
     The drum 8 is therefore locked and the cable is maintained in its wound state. 
     When, for some reason, it is required to open instantaneously the smoke outlet, the glass protecting the over-ride fist operated device 28 is broken by punching it with the fist, for example, the effect of which is to open the supply circuit of the radial electromagnetic locking and release means 15, and therefore to free the transmission through the pinions 13, 11 and 9, which also frees the drum 8. An instantaneous opening of the smoke outlet is therefore possible since the cable unwinds freely from the drum 8. 
     The premises, staircases, elevator wells and other ducts are also placed instantaneously in communication with the open air. 
     It should be noted that the radial electromagnetic locking and release means 15 is designed such as to permit its locking and unlocking in all positions intermediate between a closed position and a totally opened position of the smoke outlet, thereby limiting the opening of the smoke outlet and also rewinding the cable at any moment for a quick closing of the smoke outlet. The radial electromagnetic release means 15, having multiple positions, permits a modulated ventilation of the premises in which are mounted the various shutters currently used in buildings. 
     In some installations the rod 20 can be replaced by an equivalent locking member such as a catch or other locking means. 
     Having fully described my invention and wishing to cover those modifications and variations which would be apparent to those skilled in the art without departing from either the scope or spirit thereof,