Patent Publication Number: US-2016222727-A1

Title: Viscous damping device for reducing the rotation speed of a winding roller

Description:
FIELD OF THE INVENTION 
     The present invention relates to a viscous damping device for reducing the rotation speed of a winding roller of a screen once such screen has been previously unrolled from the roller against an energy storing device, which causes the rotation of the roller as the screen is being rewound, as defined in the preamble of claim  1 . 
     Particularly, the present invention concerns a device comprising a shaft, with a first end having means for axial coupling thereof to the screen winding roller, a rotor, coaxially placed on said shaft, a box-like element enclosing said rotor, as well as means for connecting said shaft to said rotor as the roller rotates and the screen is rewound and for disconnecting said shaft from said rotor as the screen is unwound from the roller. 
     Preferably, but without limitation, the present invention relates to a viscous damping that may be used on a vehicle, such as a car, a motor caravan, a camping trailer, a bus, a truck, a tractor, but also to be used in civil and naval construction, and the like. 
     BACKGROUND ART 
     Roller blind-like screens are known to be mainly used for shading windows, although they also find application in other fields such as refrigerated displays in supermarkets, to cover frozen goods during closing hours and to assist in ensuring thermal insulation in combination with the conventional sliding cover that is used by customers during shopping hours. 
     The screen or panel is known to be wound around a roller associated with an energy storing device, usually a spring, which is loaded when the screen is pulled at one end to extend over the opening to be screened, and is locked thereupon using a conventional roller locking/unlocking mechanism, as is known in the art. 
     As the locking mechanism is released for the screen to leave its extended position and be wound up on the roller, the energy storing device, usually a spring, if not appropriately controlled, releases the energy stored therein by quickly rotating the winding roller, which might cause damage both to the screen, which may thus be broken, and to the winding roller supporting devices. 
     In view of obviating this drawback, the rollers for rolling screens or panels have been equipped in the art with damping devices for reducing the rotation speed of the roller as the screen is being rewound, in the form of either hydraulic clutch or magnetic clutch devices, as well as combined damping devices with hydraulic and magnetic clutches. 
     One exemplary embodiment of a damping device using magnetic clutches is disclosed in U.S. Pat. No. 4,681,279. 
     These rotation speed reducers perform a desired speed-reducing action as the screen is being automatically rewound on the roller due to the stored energy, and oppose a resistance as the screen is being deployed, and if such resistance were not excluded it would add to the resistance exerted by the spring of the energy storing device, which is now being loaded, whereby a relatively high pulling force would be required to be exerted on the screen. 
     In view of obviating this drawback, the prior art suggests the use of mechanisms placed between the screen winding roller and the damping device, for excluding the opposing force of the latter, such that the operator would be only required to overcome the resistance of the spring of the energy storing device as the screen is being deployed. 
     Nevertheless, these mechanisms would increase the dimensions of screen winding devices, especially in the axial direction, such that they might not fit within the spaces available in the various applications of use. 
     This is particularly true in the case of refrigerated displays in supermarkets, which have screens adapted to cover their openings during closing hours, in association with the conventional lifting or sliding doors that are used during shopping hours. 
     Here, the provision of large devices is not compatible with the narrow space available between the doors and the underlying product-containing compartment. 
     OBJECT OF THE PRESENT INVENTION 
     Therefore, the main object of the present invention is to provide a viscous damping device for reducing the rotation speed of the screen winding roller, that may be inserted during the screen rewinding step only and has a compact size, with small axial and radial dimensions. 
     This object is fulfilled by a device as defined in claim  1  below. 
     ADVANTAGES OF THE PRESENT INVENTION 
     The present invention provides a device that affords improved reliability and simpler installation and has a more compact size as compared with prior art counterparts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be now described in greater detail with reference to a preferred embodiment thereof, given by way of illustration and without limitation, and shown in the annexed drawings, in which: 
         FIG. 1  is a partial schematic exploded view of the structure of a lateral support of a winding roller of a rolling screen; 
         FIG. 2A  is an exploded view of a part of  FIG. 1 ; 
         FIG. 2B  is an exploded view of the main parts of a device of  FIG. 2A ; 
         FIG. 3  shows an exploded view of the viscous damping device, equipped with the magnetic device allowing it to be only inserted as the screen is being rewound, according to the invention; 
         FIG. 4  shows a cross sectional view, transverse to the axis of rotation of the winding roller, of the magnetic device for inserting the damper in the position it assumes as the screen is unwound in a counterclockwise direction; 
         FIG. 5  shows a cross sectional view, transverse to the axis of rotation of the winding roller, of the magnetic device for inserting the damper in the position it assumes as the screen winding roller is rotated at a reduced speed. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the aforementioned figures, and particularly  FIG. 1 , numeral  1  designates a lateral support of the end  2  of a winding roller  3  for a conventional screen panel, not shown. 
     A second support, not shown, shall be intended to be placed at the other end of the winding roller  3 . 
     The support  1  is used to mount the winding roller  3  level with the window to be screened or the opening to be covered, e.g. in refrigerated displays in a supermarket, which are not shown because they have a conventional construction and are not useful to understand the present invention. 
     A device, generally referenced  4 , is placed on the opposite side of the support  1  and is axially connected to the roller  3 , for reducing the rotation speed of the latter when, as it is released from the lock device, as schematically exemplified by the frame  5 , the tooth  6  and the front teeth  7 , it is rotated by the energy storing device, typically consisting of a spring, not shown due to its conventional construction, which had been loaded as the screen panel was deployed with the roller rotating in the opposite direction. 
     Referring to  FIG. 2A , the device  4  comprises a viscous part  4 A and a magneto-mechanical part  4 A. 
     In one aspect, the viscous part  4 A is associated by a snap-fit joint with the magneto-mechanical part  4 B, with a tight seal being created therebetween by an appropriate o-ring  16 A. 
     Particularly, also referring to  FIG. 2B , the viscous part  4 A comprises a body  4 A′ and a rotor  4 A″, which are mechanically connected together and sealed by the o-ring  16 ′. 
     A known viscous material, e.g. silicone oil or grease, is placed within the viscous part  4 A, with the interposition of the o-ring  16 ′ and the provision of an end plug  16 A, for performing a damping action, as more clearly shown below. 
     In other words, the viscous part  4 A contains a viscous material in which said rotor  4 A″ is dipped. 
     Referring now to  FIG. 3 , it shall be noted that the magneto-mechanical portion  4 B of the device  4  of the invention comprises a shaft  8  which has press-fit means  10  at its first end  9 , for axial connection with the end  2  of the roller  3 . 
     At the second end  11 , the shaft  8  has a wheel  12  with a plurality of teeth  12  that form a corresponding plurality of recesses  14  therebetween  14 . 
     The toothed wheel  12  is rotatably joined with the shaft  8 . 
     A rotor, in the form of an annular element  15 , is arranged coaxial with said shaft  8  and radially fits onto said wheel  12  with the plurality of teeth  13 . 
     Particularly, according to the invention, said wheel  12  with the plurality of teeth  13  and recesses  14  is axially enclosed within the annular shape of the rotor. 
     A box-like element  16  encloses said annular element  15  and also has a tubular portion that covers an axial portion of the shaft  8  on the side of the end  9 , while allowing access to the means  10  for axial connection with the winding roller  3 . 
     The annular element  15  has at least one pair, preferably two pairs of hollow seats, generally referenced  18  and  19 , in a radial portion  15   a  thereof. 
     Each seat of a pair is in mirror symmetry with the other, for a reason that will be more apparent hereinbelow. 
     Each pair has a first opening  20  and  21  and a second opening  23  and  24  respectively, which are formed at the outer peripheral surface  22 . 
     The first opening  20  and  21 , and the second opening  23  and  24  are axially opposed to each other. 
     The first and second openings of each seat have an abutment element member  25 ,  26  respectively, projecting toward the center of the annular element  15 . 
     The seats  18  and  19 , which preferably have a circular section, have at least one magnet therein, referenced  27 , in alternation with each other according to the direction of rotation of the winding roller  3 , such magnet being free of axially sliding in the seat toward the teeth  13  and recesses  14  of the wheel and vice versa, according to the direction of rotation of the roller  3  and the wheel  12  axially connected thereto. 
     The cross section of the magnet  27  conforms to that of the seats  18  and  19  and is preferably a circular section. 
     The shaft  8  has an axial cavity  28  which forms a seat for housing an additional magnet, referenced  29 , which is located at the toothed wheel  12  and is designed to cooperate with the magnet  27  as the screen is being rewound, as better explained hereinbelow. 
     The seat  28  and the magnet  29  also preferably have a circular cross section. 
     Particularly referring to  FIGS. 4 and 5 , the teeth  13  of the toothed wheel  12  have flat sides, and the sides of successive teeth form respective recesses  14  whose section, as taken perpendicular to the axis of rotation X-X of the shaft  8  and the wheel  12 , forms substantially a right angle, with the vertex coinciding with the bottom of the recess. 
     As described above, particularly referring to  FIGS. 4 and 5 , which show two magnets  27 , one in the opening  23  of the seat  19  and the other in the opening  21  of the seat  18 , considering that the screen will be deployed by a counterclockwise rotation of the roller  3  (see  FIG. 4 ), the roller  3  and hence the toothed wheel  12  will rotate freely and the screen may be freely deployed only against the action of the elastic means of the energy storing device. 
     This is because the profile of the teeth  13  of the wheel  12  prevents the magnets  27  from falling into the recesses  14  because, as the wheel rotates  12 , the teeth  13  push it toward the openings  21 ,  23  of the respective seats  18 ,  19 . 
     During such rotation, the conventional energy storing device (spring) is loaded without any rotation of the annular rotor  15  and with no motion being thus transmitted to the viscous part  4 A. 
     As the screen is rewound, when the locking mechanism  5 ,  6 ,  7  is released in a conventional manner, the roller  3  is rotated, here clockwise, by the action of the energy storing device. 
     During this rotation, the magneto-mechanical device  4 B of the invention engages the rotor  15  which rotates in the box-like element  16  and transfers motion to the viscous portion  4 A through the mechanical fit specially designed for this purpose. 
     Thus, as soon as an angular clockwise movement of the wheel  12  causes a recess  14  to be available under the magnets  27  the latter are attracted by the magnet  29  housed in the cavity  28  of the shaft  8  and fit into that recess to the abutment  25 , thereby causing the rotor  15  to be rotatably joined with the wheel  12  and the shaft  8  that supports it. 
     In order to reverse the motion of the roller, the magnets  27  shall be simply placed in the seats  20  and  24  of the pairs  18  and  19  respectively. 
     The above disclosure clearly shows that the damping device has a very compact size, as the members that are designed to insert the damping section of the device as the screen is being rewound fall within the axial footprint of the damping part, i.e. the rotor  15 . 
     Particularly, the provision of the magnetic elements  17 ,  29  in the magneto-mechanical portion  4 B results in a more compact viscous portion  4 A. The size of the viscous portion  4 A may be also reduced according to the various damping requirements and the density of the silicone oil in use. 
     It shall be appreciated that, as the volume occupied by the viscous portion is decreased, then a more compact damping device may be obtained, which may be used even in narrow-space applications. 
     Those skilled in the art will obviously appreciate that a number of changes and variants may be made to the above device, still within the scope of the invention, as defined in the following claims.