Object sensing apparatus

Claim 2

Apparatus for sensing the presence of an object in the path of a travelling mechanism movable by drive means over a fixed path into which objects or persons may enter comprising, a source of electrical energy, means in circuit with said electric energy to receive said energy and thereby provide an output signal modulated to produce a signal with modulation components different from ambient light conditions, radiant energy emitting means for receiving said signal and producing a radiation output beam from said signal, radiation sensitive means for receiving said modulated radiation output from said emitting source and transmitting a control signal derived therefrom and including said modulation components, filter means for detecting from said control signal the presence of said modulation components in said radiation output, drive control means sending said drive means to a zero speed state when the modulation components in said radiation output of said control signal drop below a predetermined value due to interruption of said beam, and movable reflection means mounted on said travelling mechanism to move therewith to form a radiant energy beam path between said emitting means and said radiation sensitive device, the reflection means being mounted so it is movable out of said beam path to interrupt said beam between said emitting means and the radiation sensitive device by encountering an object introduced in the travel path of said mechanism.

Claim 3

Apparatus for sensing the presence of an object in the path of a travelling mechanism movable by drive means over a fixed path into which objects or persons may enter comprising, a source of electrical energy, means in circuit with said electric energy to receive said energy and thereby provide an output signal modulated to produce a signal with modulation components different from ambient light conditions, radiant energy emitting means for receiving said signal and producing a radiation output beam from said signal, radiation sensitive means for receiving said modulated radiation output from said emitting source and transmitting a control signal derived therefrom and including said modulation components, filter means for detecting from said control signal the presence of said modulation components in said radiation output, drive control means sending said drive means to a zero speed state when the modulation components in said radiation output of said control signal drop below a predetermined value due to interruption of said beam wherein said machine includes an end portion about which said mechanism moves, said radiation output being precluded from transmission to said radiation sensitive means during movement of said mechanism about said end portion, and including switching means operable in response to said mechanism commencing movement about said end portion for applying a biasing signal to maintain the amplitude of said control signal above said predetermined value.

Claim 4

Apparatus for sensing the presence of an object in the path of a travelling mechanism movable by drive means over a fixed path into which objects or persons may enter comprising, a source of electrical energy, means in circuit with said electric energy to receive said energy and thereby provide an output signal modulated to produce a signal with modulation components different from ambient light conditions, radiant energy emitting means for receiving said signal and producing a radiation output beam from said signal, radiation sensitive means for receiving said modulated radiation output from said emitting source and transmitting a control signal derived therefrom and including said modulation components, filter means for detecting from said control signal the presence of said modulation components in said radiation output, drive control means sending said drive means to a zero speed state when the modulation components in said radiation output of said control signal drop below a predetermined value due to interruption of said beam wherein said machine includes an end portion about which said mechanism moves, said radiation output being precluded from transmission to said radiation sensitive means during movement of said mechanism about said end portion, and including switching means operable in response to said mechanism commencing movement about said end portion for applying a biasing signal to maintain the amplitude of said control signal above said predetermined value.

Claim 5

Apparatus as set forth in claim 2 including braking means for said mechanism, said drive control means being operable to energize said braking means to arrest the movement of said mechanism coincidently with programming said drive means to said zero state.

Claim 6

Apparatus as set forth in claim 3 wherein said mechanism inlcudes a forward wall facing the direction in which said mechanism moves, said forward wall having an upper section and a lower section vertically spaced from said upper section; said emitting means being mounted on said upper section in position to direct a beam of radiant energy in a path forward of said forward wall to illuminate said radiation sensitive means.

Claim 7

Apparatus as set forth in claim 4 including reflector means positioned on said mechanism generally in the plane of said lower section for transmitting the beam to said radiation sensitive means.

Claim 8

Apparatus as set forth in claim 4 including reflector means affixed in a position remote from said mechanism and below the plane of said lower section for transmitting the beam to the radiation sensitive means.

Claim 9

Apparatus as set forth in claim 3 wherein said mechanism includes a forward wall facing the direction in which said mechanism moves, said forward wall having an upper section and a lower section vertically spaced from said upper section; said emitting means being mounted on said lower section in position to direct said beam in a path forward of said forward wall to illuminate said radiation sensitive means.

Claim 10

Apparatus as set forth in claim 7 including reflector means positioned on said mechanism generally in the plane of said upper section for transmitting the beam to said radiation sensitive means.

Claim 11

Apparatus as set forth in claim 7 including reflector means affixed in a position remote from said mechanism and above the plane of said upper section for transmitting the beam to the radiation sensitive means.