Level ride liftgate with ramping action platform

A lift comprising:

• a support means;
• an upper link pivotally supported at a forward end by said support means whereby a rear end of said upper link is vertically moveable;
• a platform having a forward edge pivotally connected to said rear end of said upper link, said platform having a planar upper surface and having a rear edge that can be brought into contact with a ground surface when said platform is inclined and supported by said upper link in a lowered position relative to said support means;
• a shackle having an upper end pivotally connected to said rear end of said upper link and having a lower end projecting downwardly beyond said forward edge of said platform whereby to engage a ground surface in said lowered and inclined position of said platform;
• a lower link means pivotally interconnected at opposite ends between said support means and said lower end of said shackle, said lower link means comprising a pair of forward and rear members jointed together by a pin;
• and a power means, extending between said support means and said rear one of said pair of members of said lower link means, to effect vertical movement of said platform,
• said lower link means and said power means operating to maintain a substantially horizontal attitude of said upper surface of said upper platform in substantially all elevations of said platform other than contact of said shackle with a ground surface and to incline said upper surface in reaction to said lower end of said shackle coming into contact with a ground surface and said platform thereupon being primarily supported by ground.

A lift having a ramping platform, said lift comprising:

• a support means;
• a spaced pair of linkage systems, each having a forward end pivotally connected to said support means whereby a rear end thereof is vertically moveable;
• a platform connected to said rear end of said linkage systems;
• each of said linkage systems comprising an upper link, a lower link means and a shackle means that is pivotally connected to said upper link and to said lower link means at said rear end of said linkage system,
• said lower link means comprising a pair of forward and rear section that are pivotally interconnected by a pin;
• stop means in said lower link means to limit relative pivotal movement of said pair of sections in one direction of rotation tending to align said pair of sections;
• means extending between said support means and said rear one of said section of said lower link means for selectively biasing said pair of sections in said one direction of rotation;
• and
• ramping means comprising said platform, said shackle means and said rear one of said pair of sections for normally biasing said pair of sections in said one direction during activation of said means extending between said support means and said rear section,
• said ramping means operating to bias said pair of sections in an opposite direction tending to misalign said pair of sections when said platform is at ground level and said means extending between said support means and said rear section is deactivated, whereby to effect ramping of said platform.

A lift comprising:

• a main frame;
• a laterally spaced apart pair of parallelogram linkage systems having forward ends pivotally connected to said main frame,
• each of said linkage systems comprising an upper link, a lower link and a shackle pivotally interconnected to rear ends of said upper link and lower link,
• each of said lower links comprising a forward section and a rear section that are pivotally interconnected by a pin;
• stop means in each of said lower links for bidirectionally limiting relative regular movement of said forward and rear sections;
• a lift frame extending between and rigidly interconnected to said rear sections of said lower links;
• a substantially rectangular platform pivotally mounted along a forward edge to said pair of upper links and to said shackles,
• said platform being pivotally moveable between a generally horizontally disposed position extending rearwardly from said shackles and an inverted position in which said platform extends forwardly from said shackles;
• and
• a laterally spaced apart pair of selectively operable means operatively interconnected between said main frame and said lift frame to oppose relative angular displacement of said forward and rear sections in a direction relative to said pin tending to misalign said forward and rear sections.

A lift comprising:

• a support means;
• a linkage system pivotally supported at a forward end by said support means whereby a rear end of said linkage system is vertically movable;
• said linkage system comprising an upper link, lower link means and a shackle means at said rear end that is pivotally connected to said upper link and to said lower link means;
• a platform;
• means interconnecting said platform to said upper link at said rear end of said linkage system in a manner to extend away from said linkage system while said platform gravitationally biases a lower end of said shackle means in a direction towards said linkage system to exert a compressive force on said lower link means;
• said lower link means comprising a pair of forward and rear members, a stop means and a pin, said pair of members being jointed together by said stop means and said pin such that when said pair of members of said lower link means is held under compression by said stop means, said pair of members are misaligned and said pin is offset beneath a straight line between the opposite ends of said pair of members of said lower link means;
• and
• a power means comprising a piston-cylinder mechanism extending between said support means and said rear one of said pair of members of said lower link means to effect vertical movement of said linkage system and said platform,
• said power means having a point of connection to said rear member of said lower link means on the opposite side of said straight line from said pin, aid power means having an axis of reciprocation that crosses said straight line between the opposite ends of said lower link means,
• said point of connection of said power means to said lower link means being within the area bounded by said linkage system,
• said piston-cylinder mechanism comprising a piston rod that is extended by said piston out of said cylinder whenever said platform is raised,
• whereby compressive force exerted by said platform on said lower link means is distributed between said lower link means and said piston-cylinder mechanism.