| 主权项 |
1. A personal stair lift to transport an individual up and down a stairway comprising a chair assembly supported on a rail assembly by a chassis assembly configured to support a lift mechanism including a drive member coupled to a reversible motor wherein said rail assembly comprises a rail disposed on each side of said chassis assembly, each said rail including an upper surface and a lower surface and said chassis assembly comprises a first upper roller and a first lower roller held in rolling engagement with said upper surface and said lower surface respectively by corresponding mounting shafts coupled to a roller bracket attached to a corresponding side of said chassis assembly to selectively move said chair assembly along said stairway when said reversible motor rotates said drive member and a brake assembly to stop movement of said chair assembly and said chassis assembly along said rail assembly when said chair assembly and said chassis assembly exceed a predetermined speed, said brake assembly comprising a brake drive member rotatably mounted to said chassis assembly and disposed to engage said upper surface of each said rail opposite said rack mounted on one end portion of a corresponding pin and a brake member including a plurality of braking elements pivotally mounted to the opposite end portion of said corresponding pin whenever said brake member is normally retained in a first or neutral position by a brake retainer member such that said plurality of braking elements are held out of engagement with said upper surface of said rail having said rack mounted thereon, said brake assembly further including a brake mechanism movable between a neutral position and a braking position comprising an actuator member pivotally coupled to said brake member by a pivot member normally retained in a first position by an actuator retainer member and a brake actuator pin affixed to said brake member adjacent said actuator member such that when said chair assembly and said chassis assembly exceed said predetermined speed rotation of the brake drive member actuates a brake actuator positioning assembly causing said actuator member to pivot against the force of said actuator retainer member engaging said brake actuator pin rotating said brake member on said brake shaft or pin against the force of said brake retainer member causing said plurality of braking elements to engage said upper surface of said rail to stop said chair assembly and said chassis assembly, said brake actuator positioning assembly comprising a first brake actuator member positioning mechanism to control the pivotal movement of said brake actuator member relative to said brake drive member and pin and a second brake actuator member positioning mechanism to control the movement of said brake actuator member relative to said brake actuator pin, said first brake actuator member positioning mechanism comprising a first actuator positioning element including a first engagement surface formed in a circular flange affixed to said pin to rotate with said brake drive member or roller and a second actuator positioning element including an actuate or concave seat affixed to said brake actuator member disposed to selectively engage each other in response to the operation of said second brake actuator member positioning mechanism, said first brake actuator member positioning mechanism comprising a plurality of first actuator positioning elements and said second brake actuator member positioning mechanism comprising a cam roller rotatably mounted within a slot or recess formed through or in said brake actuator member adjacent said second actuator positioning element and a cam including a plurality of cam surfaces corresponding to said plurality of first actuator positioning elements attached to said brake pin disposed to engage said cam roller as said brake drive member and said brake shaft rotate such that the personal stair lift travels along said rail, engagement between said cam roller and said cam surfaces in combination with said actuator retainer member causes said brake actuator arm or member to rock or oscillate on said pivot member allowing said second actuator positioning element to clear beneath said first engagement surface of said first actuator positioning element and when the speed of said personal stair lift exceeds said predetermined level the speed of rotation of the brake drive member rotates said brake shaft at an increased speed increasing said rotational speed of said cam and said cam surfaces engaging said cam roller such that said brake actuator arm is rotated to said second position against the force of said actuator retainer member for sufficient period of time causing said first engagement surface of said first actuator positioning element to engage said second actuator positioning element, rotating said brake actuator arm against said brake actuator pin to rotate said brake member until said plurality of elements engage said upper surface of said rail to stop said personal stair lift, wherein said lift mechanism is coupled to a transmission assembly by said drive member to selectively move said chassis assembly and wherein each said rail includes a transmission channel and wherein said transmission assembly comprises a transmission guide channel including substantially parallel side walls disposed between said transmission channels having a rack disposed within one of said transmission channels formed on the inner portion of one of said rails and a gear disposed in operative engagement with said rack coupled to said drive member of said reversible drive motor. |
