Transport mechanism for stairway elevator

Claim 2

In a stairway elevator having a housing mounted on rails for movement up and down the stairway and a source of controlled electromotive power mounted in said housing for movement therewith, an improved transport mechanism comprising: a. a threaded shaft mounted on said stairway and fixed against rotation; b. a drive nylon nut having an Acme thread in threaded engagement with said shaft for movement therealong, said nut being driven by drive means engaged with said nut and said motor; and c. bearing means supporting said drive means and distriButing the torque load along said shaft.

Claim 3

The invention of claim 1 wherein said bearing means comprises a tubular member disposed about said shaft having a plurality of bearings engaging said housing and said tubular member to provide for relative rotation therebetween.

Claim 4

The invention of claim 2 wherein said tubular member has a bearing bushing at the end thereof remote from said drive means and disposed proximate to said shaft.

Claim 5

The invention of claim 1 wherein a safety means is provided mounted on said shaft and movable with said nut to prevent uncontrolled descent of said elevator with respect to said shaft in the event of failure of said nut.

Claim 6

The invention of claim 4 wherein said safety means comprises an auxiliary nut in threaded engagement with said shaft and connected to said drive nut for movement therewith.

Claim 7

The invention of claim 5 wherein said safety means also includes an electrical actuating means to cut off the electric motive supply to said motor in the event of failure of said drive nut.

Claim 8

The invention of claim 6 wherein said drive nut is pin connected to said auxiliary nut to provide a means for both rotating said auxiliary nut and allowing said drive nut to slide toward said auxiliary nut and rest against it in the event of failure of the threads of said drive nut.

Claim 9

In a stairway elevator having a housing mounted on rails for movement up and down the stairway and a source of controlled electromotive power mounted in said housing for movement therewith, an improved transport mechanism comprising: a. a threaded shaft mounted on said stairway and fixed against rotation; b. a drive nylon nut having an Acme thread in threaded engagement with said shaft for movement therealong, said nut being driven by drive means engaged with said nut and said motor; c. bearing means supporting said drive means and distributing the torque along said shaft; d. safety means mounted on said shaft and movable with said nut for prevention of uncontrolled descent of said elevator with respect to said shaft in the event of failure of said nut, said safety means comprising an auxiliary nut in threaded engagement with said shaft and connected to said drive nut for movement therewith and including electrical actuating means to cut off the electromotive supply to said motor in the event of failure of said drive nut wherein said electrical actuating means comprises an electrical switch mounted to said housing and engaging said auxiliary nut and so positioned with respect thereto that relative movement along said shaft of said drive nut toward said auxiliary nut will cause said switch to be actuated and cut off the electromotive supply to said motor.

Claim 10

In a stairway elevator having a housing mounted on rails for movement up and down the stairway and a source of controlled electromotive power mounted in said housing for movement therewith, an improved transport mechanism comprising: a. a threaded shaft mounted on said stairway and fixed against rotation; b. a drive nylon nut having an Acme thread in threaded engagement with said shaft for movement therealong, said nut being driven by drive means engaged with said nut and said motor; c. bearing means supporting said drive means and distributing the torque along said shaft; d. safety means mounted on said shaft and movable with said nut for prevention of uncontrolled descent of said elevator with respect to said shaft in the event of failure of said nut, said safety means comprising an auxiliary nut in threaded engagement with said shaft and connected to said drive nut for movement therewith and including electrical actuating means to cut off the electromotive supply to said motor in the event of failure of said drive nut wherein said electrical actuating means comprises an electrical switch mounted to said housing and engaging said auxiliary nut and so positioned with respect thereto that relative movement along said shaft of said drive nut toward said auxiliary nut will cause said switch to be actuated and cut off the electromotive supply to said motor.

Claim 11

The invention of claim 1 wherein limit means are provided attached to said housing and actuated by a bumper to cut off the electromotive power to said motor upon engagement with any object sufficient to cause relative movement between the bumper and the housing, thereby allowing the elevator to come to a stop.