A device for controlling the closing movement of a sliding door

Abstract: A movement control device (17) is used for controlling the closing movement of a sliding door (10), which is movable between open and closed positions. The door is biased towards one of these positions by a weight (18), which is connected to the door via a wire or string (15). The control device (17) comprises a frame (22), which forms part of or is connectable to said weight (18). A wire reversing pulley or roller (40) is rotatably mounted on the frame has a peripheral, circular groove or track (41) formed therein for receiving said wire (15) and defining a first plane. An automatic braking means, such as an eddy current braking device (34) is mounted on the frame (22) and drivingly connected to the reversing pulley (40). The control device further comprises a guide pulley (46), which is rotatably mounted on the frame (22) above the reversing pulley (40) and which has a circular groove or track (47) formed therein defining a second plane. This second plane defines an acute angle with said first plane. The tension wire (15) may then be passed around the reversing pulley and into engagement with opposite sections of the guide pulley such that the wire parts extending between the pulleys are mutually crossing without contacting each other. Thereby a firm non-slip engagement between the wire (15) and the reversing pulley (40) may be obtained. The frame may be in the form of a parallelepiped shaped housing (22) having a hinge connected cover part (28) on which the guide pulley (46) is mounted.

Description: The present invention relates to a device for controlling the closing movement of a sliding door, such as a fire door or another self-closing door, which is movable between open and closed positions and biased towards one of these positions by a weight, which is connected to the door via a wire, a string or a similar elongated tension transmitting member. Such controlling device, which is known from DE-U-299 09 694, comprises a frame, which forms part of or is connectable to said weight, a wire reversing pulley or roller rotatably mounted on the frame and having a peripheral, circular groove or track formed therein for receiving said wire and defining a first plane, automatic braking means mounted on the frame and drivingly connected to the reversing pulley, and a guide pulley rotatably mounted on the frame above the reversing pulley and defining a circular groove or track therein defining a second plane. It is important that the elongated tension transmitting member is engaging with the reversing pulley so as to avoid slipping of the elongated member in relation to the reversing pulley or roller during operation. In the embodiment illustrated in the above DE-U-299 09 694 the guide pulley and the reversing pulley are substantially parallel, and the elongated member in the form of a rope is passed to the weight through an eye, around the reversing pulley, thereafter around the guide pulley, again around the reversing pulley and out through another eye. According to an embodiment disclosed in EP-B-0 531 246 slipping of the elongated member is prevented by using an elongated member in the form of a chain and a corresponding sprocket as the reversing pulley or roller. However, EP-B-0 531 246 also mentions that a pull wire may be used as long as a mainly slip-free transmission between the wire and the transmission wheel is ensured, e.g. by winding the wire twice around the transmission wheel. The present invention provides a control device of the above type in which a non-slip engagement between the wire or a similar elongated tension transmitting member and the reversing pulley may be obtained in a simple manner. The control device according to the invention is characterised in that said second plane defines an acute angle with said first plane, whereby the tension wire may be passed around the reversing pulley and into engagement with opposite sections of the groove of the guide pulley such that the wire parts extending between the pulleys are mutually crossing without contacting each other. Because of the crossing wire parts the wire is in contact with the reversing pulley along a major part of its circumference. Thereby the desired non-slip engagement between the reversing pulley and the wire may be obtained. The diameter of the reversing pulley may be chosen so as to obtain a suitably long circumferential length along which the reversing pulley is contacted by the wire. Therefore, the diameter of the reversing pulley preferably substantially exceeds the diameter of the guide pulley. As an example, the effective diameter of the reversing pulley may be two or three times the effective diameter of the guide pulley or more. The grip between the wire and the reversing pulley and/or the guide pulley may be further improved when the peripheral groove therein has a cross-sectional shape with a radially inwardly decreasing width. The frame of the device according to the invention may comprise a first part carrying the reversing pulley and a second part carrying the guide pulley, said first and second parts being mutually hinge connected. Thus, these two frame parts may be moved between a first position, in which the pulleys are located in their mutual operational positions, and a second servicing position, in which the pulleys are accessible. In a preferred embodiment the axis of the hinge connection extends substantially parallel with the rotational axis of the reversing pulley. In order to protect the pulleys and other movable device parts against dust and other foreign matter the frame may define a housing, and said second frame part may then form one or more wall parts of such housing. The said second frame part may then form a kind of hinged lid or cover. This means that the housing is closed when the second frame part is in said first position and opened when the second frame part has been moved to its second, servicing position. The hinged frame part or cover is preferably releasably fastened to the first frame part in its said first position, for example by means of screws or other releasable connecting or fastening means. In the preferred embodiment the second frame part or cover forms a top wall and a side wall of a substantially parallelepiped shaped housing, and the guide pulley may then be mounted on said top wall adjacent to an opening or openings therein allowing wire parts to pass there through. The automatic braking means may be of any conventional type, which may keep the velocity of the associated sliding door within desired limits. Preferably, the braking means comprise an eddy current brake having a rotor, which is driven by the reversing pulley via meshing gearwheels, and one of these gearwheels may then be mounted on its shaft by means of an overrunning clutch or similar means transmitting the rotational movement of the reversing pulley to the brake rotor in one rotational direction only. The slide door may then be moved in one direction, for example to its open position without any braking effect, while the braking means secures that the velocity of the door is kept within the desired limits when the door is moved in the opposite direction. In this specification with claims terms such as "above", "top", "bottom", "side" etc. refer to the position of the movement control device during normal use. The invention will now be described more in detail with reference to the drawings, wherein Figs. 1 and 2 are diagrammatic side views of two different sliding door arrangements in which the movement control device according to the invention may be used, Fig. 3 is a perspective view of an embodiment of the movement control device according to the invention having a housing, which is shown in its normal, closed position, Fig. 4 is a sectional view of the device shown in Fig. 3, Fig. 5 is a diagrammatic perspective view illustrating how the wire is passed around the pulleys, and Figs. 6 and 7 are perspective views illustrating the device shown in Figs.3 and 4 with the housing in an open position. Fig. 1 illustrates an arrangement comprising a sliding fire door 10 movable along a guide rail 11 on which the door is suspended by means of suspension members 12 with rollers. The door 10 is normally retained in an open position, in which an anchor plate 13 connected to the door is kept in contact with a fixed electromagnet 14. One end of a wire 15 is connected to the door 10 and the other end is fixed and stationary. The wire 15 is passed over a pulley 16 and into engagement with a movement control device 17 according to the invention, which is connected to a weight 18. The combined device 17 and weight 18 is movably arranged within a vertically extending tubular well or housing 19. In case of fire a safety fuse (not shown) may cut off the energy supply to the electromagnet. The door 10 will then start moving from its open to its closed position (shown in Fig. 1) under the influence of the weight 18, and the rate of movement is controlled by the device 17 and the braking device described below. In the door arrangement shown in Fig. 2 the anchor plate 13 is connected to a free end of the wire 15 and is usually kept in contact with the electromagnet 14. A carrier member 20 extends upwardly from the door 10 and the wire 15 is passed through a hole 21 defined in the carrier member. The door 10 may manually be moved freely along the guide rail 11 and be placed in any desired position when the anchor plate 13 is kept in contact with the electromagnet 14. However, in case of fire the anchor plate 13 is released and moved to the left in Fig. 2 by the falling weight 18. When the anchor plate 13 reaches the carrier member 20 the door 10 will be moved to its fully closed position and the closing movement will be controlled by the device 17. It should be understood that the device 17 according to the invention could also be used in connection with a vertically sliding door or a drop door. In this case the gravity of the door is biasing the door towards its closed position and the combined device 17 and weight 18 may form a counterweight. Figs. 3-7 illustrate a preferred embodiment of the device 17 according to the invention. The device 17 comprises a frame in the form of a substantially parallelepiped shaped housing 22. The housing 22 is divided into a basic unit 23 including a rear wall 24, a pair of opposite sidewalls 25, and a bottom wall part 26 with a downwardly extending flange 27. The housing 22 further comprises a cover unit 28, which includes a top wall 29, a front wall 30, and a bottom wall part 26 with a flange 27. The cover unit 28 is connected to the basic unit 23 at the upper edge of the rear wall 24 by means of a hinge connection 31 and may be moved between an open position as illustrated in Figs 6 and 7 and a closed position as shown in Fig. 3. In the closed position the units 23 and 28 may be releasably interconnected, for example by means of screws 32. Furthermore, the adjacent flanges 27 may be interconnected and fastened to a weight 18 (shown in Figs. 1 and 2, but not in Figs. 4-7) by means of bolts 33. The movement control device 17 comprise an eddy current braking device 34 of known type having a rotor 35 fixed on a shaft 36 extending between and being rotatably mounted in the opposite housing sidewalls 25 and a stator 37. The stator 37 comprises a pair of stator plates with magnets arranged on either side of the rotor 35. The outer stator plate is mounted on the inner side of the adjacent housing side wall 25, and the inner stator plate is mounted on screws 38 or similar mounting devices extending through the housing side wall 25. At least some of the screws 38 are surrounded by coil springs 39 or similar biasing means biasing the inner stator plate inwardly away from the adjacent housing sidewall. This means that the air gap and, consequently, the braking force may be adjusted by tightening or loosening the screws 38 by means of a screw driver or another tool from the outside of the housing sidewall 25. A reversing pulley or roller 40 having a peripheral, inwardly tapered groove or track 41 formed therein is fixed on a shaft 42 extending substantially parallel with and above the shaft 36. The opposite ends of the shaft 42 is also rotatably mounted in the opposite housing side walls 25. A gearwheel 43 is mounted on the shaft 42 by means of an overrunning clutch 44 or a similar device connecting the gearwheel 43 to the shaft 42 only when the shaft is rotated in one predetermined direction. The gearwheel 43 is engaging with a gearwheel 45, which is fixed on the shaft 36. The diameter of the gearwheel 43 is substantially larger than that of the gearwheel 45 such that rotation of the reversing pulley 40 in a predetermined direction causes the rotor 35 of the braking device 34 to rotate at a substantially higher rotational speed, while rotation of the pulley 40 in the opposite direction does not cause rotation of the rotor 35 because the overrunning clutch 44 does not transfer the rotational movement of the shaft 36 to the gearwheel 43. This means that the sliding door 10 shown in Figs 1 may be moved to an open position without any braking effect performed by the braking device 34. A guide pulley 46 having a peripheral groove or track 47 formed therein is rotatably mounted on the inner surface of the top wall 29 opposite to an opening 48 formed therein by means of a bracket 49. The axis of rotation of the guide pulley defines an acute angle with a plane defined by the axes of the shafts 36 and 42. When the elongated tension member 15 (Figs. 1 and 2), which may be a wire, a string, a line, a rope, or the like, is passed around the reversing pulley 40 and into contact with opposite sides of the smaller guide pulley 46 such that the wire parts between the pulleys 40 and 46 are crossing each other as shown in Figs. 5 and 6 the wire 15 is engaging with the tapered groove 41 therein along a major part of the peripheral length of the groove. Thereby a firm non-slip engagement may be obtained between the wire 15 and the pulley 40. Because the axes of the pulleys 40 and 46 extend in different, non-parallel directions interference between the crossing wire parts may be avoided. During operation of the movement control device 17 the basic unit 23 and the cover unit 28 forming the housing 22 are interconnected by the screws 32 and the bolts 33. However, when the device 17 is to be installed and the wire 15 has to be passed around the pulleys 40 and 46 and in case of maintenance and repair of the device the screws 32 and the bolts 33 may be removed and the housing 22 may be opened by tilting the cover unit 28 around the hinge connection 31 to an open position as illustrated in Figs. 6 and 7. It should be understood that various changes and modifications of the device illustrated in the drawings could be made without departing from the scope of the appended claims. As an example, the eddy current braking device shown and described could be replaced by any other type of automatic braking device.

Claims: A device for controlling the closing movement of a sliding door (10), which is movable between open and closed positions and biased towards one of these positions by a weight (18), which is connected to the door via a wire, a string, or a similar elongated tension transmitting means (15), said control device (17) comprising a frame (22), which forms part of or is connectable to said weight (18), a wire reversing pulley or roller (40) rotatably mounted on the frame and having a peripheral, circular groove or track (41) formed therein for receiving said wire (15) and defining a first plane, automatic braking means (34) mounted on the frame (22) and drivingly connected to the reversing pulley (40), a guide pulley (46) rotatably mounted on the frame (22) above the reversing pulley (40) and defining a circular groove or track (47) therein defining a second plane, characterised in that said second plane defines an acute angle with said first plane, whereby the tension wire may be passed around the reversing pulley and into engagement with opposite sections of the guide pulley such that the wire parts extending between the pulleys are mutually crossing without contacting each other. A device according to claim 1, wherein the frame (22) comprises a first part (23) carrying the reversing pulley (40) and a second part (28) carrying the guide pulley (46), said first and second parts being mutually hinge connected. A device according to claim 2, wherein the axis of the hinge connection (31) extends substantially parallel with the rotational axis of the reversing pulley (40). A device according to claim 2 or 3, wherein the frame defines a housing (22), said second frame part (28) forming one or more wall parts of said housing. A device according to claim 4, wherein the second frame part (28) forms a top wall (29) and a sidewall (30) of a substantially parallelepiped shaped housing (22), the guide pulley (46) being mounted on said top wall. A device according to any of the claims 1-5, wherein the automatic braking means comprise an eddy current brake (34) having a rotor (35), which is driven by the reversing pulley (40) via meshing gearwheels (43,45), one (43) of said gearwheels being mounted on its shaft (42) by means of an overrunning clutch (44) or similar means transmitting the rotational movement of the reversing pulley to the brake rotor in one rotational direction only.

Inventors: LEMMING MICHAEL ERIK, LEMMING, MICHAEL ERIK
Applicants: NORHOLM & K LEMMING AS N, N. NORHOLM & K. LEMMING A/S
Application year: 2000
Main classification: E05F1
IPC codes: E05F1, E05F5