Patent Publication Number: US-8966714-B2

Title: Hinge having an embedded safety switch

Description:
The present invention relates to a hinge having an embedded safety switch, otherwise said hinge with embedded travel end. 
     Hinges of this type had existed on the market, and are employed in industrial machinery, in particular for connecting bonnets to the frame, when it is particularly dangerous to access inside the machinery when it isi in use. Likewise, this kind of device may be used for standard access doors, to signal the entry or the exit of people. 
     Hinges with embedded travel end have recently replaced classic inventions, such as for example rotation travel ends or tab travel ends, since they have proved easier to be installed and capable of guaranteeing constant performances in the long run. 
     For example, the Applicant had filed a hinge of the type consisting of two main wing-shaped constituent members, and having a mutual-engagement area on a common pivoting axis, which provides that with one of said wings a head of the pivoting axis is integral, having a cam profile, and that at the other end a switch body be associated from which a control peg protrudes, the outer end of which engages with said cam profile and the end of which inside the switch body acts on an actuation button of the actual switch. 
     However, during marketing the users owning machinery with non-conventional openings has raised the need to obtain—during mounting—initial actuation angles different from the standard 0°. 
     Moreover, the requirement has been perceived to protect the switch body actuation mechanics from water and dust in as sealed a manner as possible, so as to allow the use of switches of unprotected switches, easier to find and economically more convenient. 
     Finally, the need has been felt to make such product more compliant of currently valid safety laws. 
     The object of the present invention is therefore to manufacture a hinge provided with a switch which has means apt to guarantee the adjustment of the actuation angle according to the panel construction requirements, and at the same time means apt to guarantee greater resistance to dusts and water, and consequently a smaller risk of breakage or malfunctioning of the device. 
     Said object is obtained through a safety hinge, apt to a constrain a door moving with respect to a fixed frame, of the type consisting of two main main wing-shaped constituent members having a mutual-engagement area consisting of loops interconnected through a small shaft, with a first one of said wings a switch body being associated, internally shaped so as to provide a channel, arranged on the extension of the mutual-engagement area, and to house a microswitch, said microswitch having an appendix housed within said channel on the top of which peg means project for the actuation of the switch, characterised in that within said appendix a bush is arranged, constrained to the movement of a second one of said wings, said bush having, along an outer annular crown thereof, a groove for the housing of said peg means in the closing position of said moving door on the fixed frame, that is, in the position of said microswitch. 
    
    
     
       Further features and advantages of the structure according to the invention result from the following detailed description of the invention, made with reference to the attached drawings, wherein: 
         FIG. 1  is a front view of the hinge according to the invention, wherein the cover of the safety switch has been removed; 
         FIG. 2  is the exploded view of the hinge of  FIG. 1 ; 
         FIG. 3  is the view along the section B-B of  FIG. 1 ; 
         FIG. 4  is a top plan view of the constituent member of the hinge of  FIG. 1  which carries the switch body; 
         FIG. 5  is a top plan view of the constituent member of the hinge of  FIG. 1  which does not carry the switch body; 
         FIG. 6  is the front view, wherein a cam member is highlighted, of a bush to be mounted on the top surface of the mutual-engagement area of the two constituent members of the hinge, of which 
         FIG. 7  is a bottom plan view. 
     
    
    
     The hinge according to the invention consists of two main constituent members  1  and  2 , identifiable as wings or hinge bodies—generally moulded of thermoplastic material, but which may be made also of other synthetic materials, or of rubber or of metal—shaped so as to have a mutual-engagement area  3 , on a common pivoting axis. 
     Within the above-said mutual-engagement area  3  the insertion of a small shaft  4  is provided, suitably shaped so that it has at the ends thereof engagement members apt to guarantee the sealing of shaft  4  in a steady position. In particular, at one end a series of ribs  5  is provided parallel to the shaft axis and evenly distributed on the cylindrical surface thereof, apt to the interference engagement with the inner wall of lower loop is projecting from member  1 . On the end of said small shaft  4  opposite to said ribs  5  an annular groove  6 , for the function better described in the following, is instead provided. 
     On the top of wing  1  switch body  7  is fastened, integrally or ultra-sound welded, having the shape of a rectangle parallelepiped box with rounded corners, preferably obtained by moulding of thermoplastic material, at the top of which a preferably cylindrical guiding collar  8  is prepared. Moreover, on the rear wall a further guiding collar  9  is prepared. These two guiding collars  8 ,  9  are both prepared to allow the passage of conductive cables which connect to switch body  7 . 
     From said body  1 —in correspondence of said one switch body ( 7 )—a top loop  1   b  departs, apt to the extension of the mutual-engagement area  3 . Loop  1   b  is connected to said switch body  7  through a channel  10 , which houses an appendix  11   a , projecting from microswitch  11 , on the end of which a peg  12  is provided free to slide in a horizontal direction. Such peg  12  acts as an actuation button of microswitch  11 . 
     A bush  13  consisting of a body with a substantially cylindrical profile, but which has at one end a knurled portion  13   a , and, at the other end, an annular crown  13   b  wherein a groove  13   c  is obtained. Above and below the area said groove  13   c  is provided there are provided toroidal notches  13   d  and  13   e  are provided, apt to house sealing O-rings. 
     Bush  13  is mounted from the top, in the cylindrical area  1   b  of wing  1 , taking care to bringe the knurled portion  13   a  into keying-on engagement with the grooves  14  provided within the top loop  2   a  of constituent member  2 . Moreover, groove  13   c  is precisely a the opening point of channel  10 , so as to be able to house said peg  12  in the way described in the following. 
     Moreover, bush  13  is shaped so as to provide an upper sealing housing for shaft  4 , internally having engagement means with the annular groove  6  of shaft  4 , apt to guarantee the positioning, fixed only in an axial direction, of the shaft. Once the described complex has been thus assembled, it is ensured that shaft  4  remains integral with hinge member  1 , due to keying on  5 - 1   a , and that bush  13  is integral with hinge member  2 , due to keying-on  13   a - 14 . Thereby, when member  2  rotates with respect to member  1 , annular crown  13   b , with groove  13   c , slides opposite peg  12  and appendix  11   a.    
     At the end of the above-described mounting, a cover  15  is snap fastened, according to a very well-known technique and therefore not illustrated nor described, to close above the hollow of appendix  11   a , so as to rule out the accidental coming off of bush  13 . 
     The mounting operations require exclusively to fasten hinge member  1  to the frame and member  2  to the door, and subsequently to insert an electric energy connector into guiding collar  8 , or into collar  9 , to suitably connect it to microswitch  11  depending on the operator&#39;s requirements. 
     The constructor will be free to adjust bush  13  so that the groove  13   c  thereof is arranged with the desired angle with respect to the conventional closing position of the moving door, so as to guarantee the activation of the safety system at the necessary angle. 
     Once the mounting of the hinge according to construction requirements has finished, body  7  is closed by a cover provided with protection seal, fastened by screws. Thereby the guarantee of insulation from water and dust is obtained. 
     During operation, with the machine, peg  12  is housed in groove  13   c , where it is kept in rest position by spring associated with appendix  11   a  and contained in the microswitch. When the door is opened, peg  12  is forced to come out of groove  13   c , resting on the cam profile  13   b  of bush  13 —which is led by the engagement with loop  2   a  to rotate integrally with the door—and consequently to withdraw towards the microswitch, along appendix  11   a . Thereby, the safety circuit is actuated, for example switching off the machinery or issuing an alarm signal. Once the door has been brought back into a closed position, per  12  is housed back in groove  13   c , consequently switching off the circuit. 
     As can be easily understood, the possibility of adjusting during adjustment the angle of the groove allows the hinge the actuation of the safety device at the required door opening angle. 
     From the above-reported description it is evident that the set objects have been reached, that is, a hinge provided with a switch which has means apt to guarantee the adjustment of the activation angle according to the panel construction requirements, and at the same time means apt to guarantee greater resistance to dust and water, and consequently fewer risks of breakage or malfunctioning of the device. 
     A special layout of the engagement area between the peg member of the switch and the bush of the pivoting member has been obtained so as to remarkably reduce the risk of undesired dust deposits. 
     However, it is understood that the protection of the above-described invention must not be considered limited to the special embodiment illustrated, but extends to any other technically equivalent construction variant, falling within the scope of the attached claims.