Draw-tight apparatus for ramp doors and the like
View Patent ↗A ramp door closure apparatus is provided for recreational vehicles, having a recessed linear actuator both draw a cable from a mounting bracket on the ramp door adjacent to the RV opening, to raise and lower the ramp door, and then cam a locking pin fixed to the ramp door into a seal tight position after the ramp door is raised. Upon release of the locking pin from the cam when opening the door, an initial push is provided to facilitate downward rotation of the ramp door. The linear actuator is selectively detachable from the cable so as to allow manual raising and lowering of the ramp door from within the RV, by means of releasable pins accessed in the mounting structure.
1. An apparatus, for raising and lowering a wall to control access to a structural opening, comprising:
the wall having a hinge at one end of the wall, connecting the wall to the structural opening, so as to allow the wall to be raised and lowered with respect to the opening,
a cable having two ends, one of which is connected to the wall, for controlling motion of the wall with respect to the hinge,
a linear actuator arrangement connected to the other end of the cable, for controlling motion of the cable,
said linear actuator arrangement having two motive stages, one of which causes motion of the cable which raises or lowers the wall, and the other of which causes motion of the wall relative to said linear actuator arrangement when the cable is not moving,
wherein the wall has a projection therefrom, and said linear actuator arrangement includes a cam for receiving said projection when the wall is raised, and motion of said linear actuator arrangement draws the projection to close the wall completely into the structural opening, and
wherein said linear actuator arrangement includes at least:
a vertically extendable drive shaft,
a draw block forming at least a portion of the cam, and having a slot therein for receiving the projection, and
a spring assembly attached between the draw block and the cable, such that when the cable is fully retracted the draw block remains movable, so as to move the projection within the slot.
2. An apparatus, for raising and lowering a wall to control access to a structural opening, comprising:
the wall having a hinge at one end of the wall, connecting the wall to the structural opening, so as to allow the wall to be raised and lowered with respect to the opening,
a cable having two ends, one of which is connected to the wall, for controlling motion of the wall with respect to the hinge,
a linear actuator arrangement connected to the other end of the cable, for controlling motion of the cable,
said linear actuator arrangement having two motive stages, one of which causes motion of the cable which raises or lowers the wall, and the other of which causes motion of the wall relative to said linear actuator arrangement when the cable is not moving,
wherein:
the structural opening is formed in a recreational vehicle,
the wall serves as a ramp door for the structural opening,
the apparatus also has locking means to releasably secure the wall in a closed position against the recreational vehicle, and
the apparatus also has a push out arrangement to initially move the wall away from engagement with the structural opening when the locking means is released,
wherein said linear actuator arrangement includes structure which allows said linear actuator arrangement to be selectively detachable from the cable, in order to allow the wall to be manually raised or lowered, and
wherein the linear actuator arrangement includes at least:
a vertically extendable drive shaft,
a draw block forming at least a portion of the cam, and having a slot therein for receiving the projection, and
a spring assembly attached between the draw block and the cable, such that when the cable is fully retracted the draw block remains movable to move the projection within the slot.