Patent Publication Number: US-9422031-B2

Title: Latching device for a movable platform

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority to Italian Patent Application No. TO2014A000594, filed Jul. 25, 2014. The disclosure of the prior application is hereby incorporated in its entirety by reference. 
     FIELD OF THE INVENTION 
     The present invention relates in general to movable platform assemblies, of the type comprising a base structure, a platform and an articulated system which connects the platform to the base structure, wherein the platform is movable between a raised position which is horizontally adjacent to the base structure and a lowered position which is horizontally far from the base structure. 
     BACKGROUND OF THE INVENTION 
     These assemblies are generally mounted on boats and are used to allow hauling and launching of a tender or similar type of marine vehicle with which the boat is equipped or for allowing swimmers to access the water. 
     Operation of the platform assemblies is usually performed by means of hydraulic or electrical devices. When the platform is in the raised position adjacent to the base structure, the actuating system which should ensure the stability thereof nevertheless has a certain amount of play such that, when a load of a certain size is mounted on the platform, the latter may lower slightly, creating a certain gap between the platform and base structure. 
     SUMMARY OF THE INVENTION 
     One object of the present invention is therefore to propose a platform assembly configured to overcome this drawback. 
     The aforementioned object is achieved according to the invention by a movable platform assembly of the type defined initially which also includes a latching device switchable into a stable locking position for locking the platform against the base structure when the platform is in the raised position, 
     wherein the latching device comprises 
     a striker element fixed to the platform, 
     a movable latching element arranged on the base structure for engaging the striker element so as to lock the platform, and 
     an actuating mechanism for actuating the latching element, 
     wherein a force applied on the platform when the latching device is in the locking position and tending to horizontally move the platform away from the base structure causes the actuating mechanism of the latching device to be blocked, 
     wherein the latching element is arranged rotatably about a rotation axis, 
     wherein the actuating mechanism comprises an articulated quadrilateral formed by a frame element fixed to the base structure, an actuating lever hinged with the frame element, the latching element hinged with the frame element, and a link member hinged, at opposite ends, with an intermediate point of the latching element and with an intermediate point of the actuating lever, respectively, 
     wherein when the latching device is in the locking position the hinge points between frame element and actuating lever, between actuating lever and link member, and between link member and latching element lie on a same straight line coinciding with the instantaneous direction of movement of the hinge point between latching element and link member. 
     Preferred embodiments of the invention are defined in the dependent claims which form an integral part of the present description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristic features and advantages of the present invention will become clear from the following detailed description provided purely by way of a non-limiting example, with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view which shows a movable platform assembly provided with a latching device according to the invention; 
         FIG. 2  is an exploded view of the latching device; 
         FIGS. 3 a  to 3 c    are a side elevation view, plan view and cross-sectional view of the latching device in an inactive condition; 
         FIGS. 4 a  to 4 c    are a side elevation view, plan view and cross-sectional view, respectively, of the latching device in an active condition; and 
         FIG. 5  is a cross-sectional view on a larger scale of the latching device in the active condition. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIG. 1 , this figure shows a platform assembly  1  according to the invention, installed on a boat. More generally, the invention relates to different platform assemblies installed on a fixed structure or on a vehicle. 
     The platform assembly  1  comprises a base structure  2  with which a platform  3  is articulated. The base structure  2  may be provided with means (not shown) for allowing fixing of the assembly  1  to the fixed structure or vehicle or, in an alternative embodiment, may be incorporated in the fixed structure or in the vehicle. 
     The assembly  1  also comprises an articulated system  4  which is formed by a plurality of bars hinged together and, by means of these bars, connects the platform  3  to the base structure  2 . Also associated with the articulated system  4  is an actuator  5  by means of which the platform  3  is movable between a raised position which is horizontally adjacent to the base structure  2  (shown in  FIG. 1 ) and a lowered position which is horizontally far from the base structure  2 . 
     According to the invention, the assembly includes a latching device  10  for locking the platform  3  against the base structure  2  when the platform  3  is in the raised position. 
     With reference to  FIG. 2  and the following figures, the latching device  10  comprises a first and a second bracket  11 ,  110  by means of which the latching device  10  is mounted on the base structure  2  of the platform assembly  1 . The first bracket  11  comprises two side pieces  11   a,    11   b  which are connected together by a first and second hinge pin  11   c ,  11   d.  Respective through-holes  11   e,    11   f  which are aligned with each other are also formed in the side pieces  11   a,    11   b . The second bracket  110  has a projection  110   a  in which a through-hole  110   b  is formed. 
     A latching element  12  in the form of a hook is hinged together with the first hinge pin  11   c  of the first bracket  11 , which is inserted inside a first through-hole  12   a  formed in one end of the latching element  12 . The latching element  12  also has a second through-hole  12   b  formed at an intermediate point of the latching element  12 . 
     An actuating lever  13  is hinged with the first bracket  11  via the aligned through-holes  11   e ,  11   f . The actuating lever  13  comprises two side bars  13   a,    13   b  which are connected together, at the opposite ends, by means of a first and second hinge pin  13   c,    13   d.  Respective through-holes  13   e,    13   f  which are aligned with each other are also formed in the side bars  13   a,    13   b  at an intermediate point along the bars. The actuating lever  13  is hinged with the first bracket  11  by means of its first hinge pin  13   c  inserted inside the aligned holes  11   e ,  11   f  of the first bracket  11 . The side bars  13   a,    13   b  of the actuating lever  13  are therefore arranged in a position situated laterally further outwards than the side pieces  11   a ,  11   b  of the first bracket. 
     A link member  14  is hinged, at one end, with the latching element  12  via the through-hole  12   b  and, at the other end, with the actuating lever  13  via the aligned through-holes  13   e,    13   f . The link member  14  comprises two side bars  14   a,    14   b  which are connected together, at the opposite ends, by means of a first and second hinge pin  14   c,    14   d.  The link member  14  is hinged with the latching element  12  by means of its first hinge pin  14   c  inserted inside the second hole  12   b  of the latching element  12  and with the actuating lever  13  by means of its second hinge pin  14   d  inserted inside the aligned holes  13   e,    13   f  of the actuating lever  13 . The side bars  14   a,    14   b  of the link member  14  are arranged in a position situated laterally more inwards than the side pieces  11   a ,  11   b  of the first bracket. 
     A second lever  15  is hinged with the second bracket  110  via the through-hole  110   b . The second lever  15  comprises two side bars  15   a,    15   b  which are connected together, at the opposite ends, by means of a first and second hinge pin  15   c,    15   d.  The second lever  15  is hinged with the second bracket  110  by means of its second hinge pin  15   c  inserted in the through-hole  110   b  of the second bracket  110 . 
     A bar  16  is hinged, at one end, with the second lever  15  by means of the second hinge pin  15   d  and, at the other end, with the actuating lever  13 , by means of the second hinge pin  13   d.  The bar  16  comprises two side pieces  16   a,    16   b  which are connected together and which have, at their opposite ends, respective through-holes  16   c,    16   d  aligned with each other and respective through-holes  16   e,    16   f  aligned with each other. The rod  16  is hinged with the second lever  15  by means of the second hinge pin  15   d  of the second lever  15  inserted in the aligned holes  16   c,    16   d  of the bar  16  and with the actuating lever  13  by means of the second hinge pin  13   d  of the actuating lever  13  inserted in the aligned holes  16   e,    16   f  of the bar  16 . The side pieces  16   a,    16   b  of the bar  16  are arranged in a position situated laterally more inwards than the side bars  13   a,    13   b  of the actuating lever  13  and in a position situated laterally more outwards than the side bars  15   a,    15   b  of the second lever  15 . 
     A linear actuator  17 , in the example a hydraulic cylinder, is at its end on the bottom side hinged with the first bracket  11  by means of the second hinge pin  11   d  of the latter and at its end on the rod side is hinged with the second lever by means of the second hinge pin  15   d  of the latter. 
     The first bracket  11 , the latching element  12 , the actuating lever  13  and the link member form an articulated quadrilateral, the first bracket  11  of which forms the fixed element or frame. 
     The first and second brackets  11 ,  110  which, together with the base structure  2  of the platform assembly  1 , constitute a fixed frame, form a second articulated quadrilateral together with the actuating lever  13 , the second lever  15  and the bar  16 ; this second articulated quadrilateral together with the first quadrilateral forms a movement mechanism, by means of which the latching element  12  may be actuated by the linear actuator  17 . 
     A striker element  20  in the form of a pin is arranged fixed together with the platform  3 . This striker element  20  is designed to be engaged by the latching element  12  so as to lock the platform  3  against the base structure  2  when the platform  3  is in the raised position. 
     An electronic control unit (not shown) is provided for controlling the linear actuator  17 ; a sensor (not shown) is provided for detecting when the platform  3  is in the raised position shown in  FIG. 1  and therefore providing an enable signal to the control unit. 
     When the system is not locked ( FIGS. 3 a -3 c   ), the latching element  12  is located in a low position, so as to allow the movement of the platform  3 . During the upwards movement of the platform, when the latter is in the raised position, the sensor sends a signal to the control unit so as to allow locking. The control electronics move the cylinder  17  so that its rod is fully extracted. The movement of the rod of the cylinder  17  causes a rotation of the second lever  15  about its rotation axis; the bar  16 , which is hinged with the second lever  15  at one end and with the actuating lever  13  at the other end, is moved; the bar  16  causes the movement of the actuating lever  13  with which the link member  14  is connected. The link member  14  acts on the latching element  12 , forcing it to perform a rotational movement about its rotation axis; during this step the latching element  12  presses against the striker element  20  fixed to the platform  20 . The movement of the latching element  12  stops when the cylinder  17  reaches the end of its stroke; the entire system is thus located in a stable locking position shown in  FIG. 1  and in  FIGS. 4 a   - 4   c.    
     In this configuration the platform  3  is locked only as a result of the position of the actuating mechanism, without application of an external force, in particular by the actuator, being required. In this position, no external force acting on the platform  3  may vary this condition. In fact, if a force acts on the platform  3  forcing it to move away from the base structure  2  and therefore downwards, the striker element  20  transmits the force to the latching element  12  which tends to rotate about its rotation axis; this movement is prevented by the fact that the link member  14 , which should move together with the latching element  12 , remains locked owing to the particular situation of the hinge points of the articulated quadrilateral associated therewith, as shown in  FIG. 5 . In  FIG. 5 , x, y and w indicate the hinge points between first bracket  11  and actuating lever  13 , between link member  14  and latching element  12 , and between actuating lever  13  and link member  14 , respectively; as can be seen, these hinge points x, y, w lie on a same straight line r coinciding with the direction of movement of the hinge point y between latching element  12  and link member  14  (blocking condition). 
     The downwards movement of the platform  3  will therefore be possible only by means of actuation of the actuating lever  13  via the bar  16 , causing this time the hydraulic cylinder  17  to be extracted. 
     Preferably, the latching device  10  is arranged so that the latching element  12  is arranged rotatably about a horizontal axis. According to an alternative embodiment it is however possible to arrange the latching device so that the latching element  12  is arranged rotatably about a vertical axis. 
     According to another embodiment of the invention, the linear actuator consists of an electric or pneumatic actuator. Alternatively, it is possible to provide a rotary actuator instead of the linear actuator. 
     According to a simplified embodiment of the system the bar  16  is replaced directly by a linear actuator which would act directly on the actuating lever  13 . 
     According to a further simplified embodiment, locking is performed manually and this acts directly or indirectly on the actuating lever  13 . 
     More generally, it is possible to provide a latching device with a different mechanism controlled by the actuator or manually, provided that a stable operating position which acts as locking position is reached.