Overhead projector

An overhead projector comprising a base, a hollow post extending up from said base, a projector head on an upper portion of said post and comprising a light source, an objective lens, and a deflection mirror, a power supply unit in a lower portion of said hollow post and supplying power for said light source, said power supply unit including an input stage in a housing which is pluggable into a socket in said post, a motor driven ventilator in said hollow post between said power supply unit and said light source, said power supply unit supplying power also to said ventilator, an air outlet opening in said post for discharge of air from said ventilator and air inlets for admitting air to cool said power supply unit and said light source, said air being drawn over said power supply unit and said light source respectively by said ventilator and discharged through said outlet opening.

An overhead projector comprising a base, a hollow post extending up from said base, a projector head on an upper portion of said post and comprising a light source, an objective lens, and a deflection mirror, a power supply unit in a lower portion of said hollow post and supplying power for said light source, a motor driven ventilator in said hollow post between said power supply unit and said light source, said power supply unit supplying power also to said ventilator, an air outlet opening in said post for discharge of air from said ventilator and air inlets for admitting air to cool said power supply unit and said light source, said air being drawn over said power supply unit and said light source by said ventilator and discharged through said outlet opening, said projector head having a power supply receptacle and in which a transparency projector is mounted on said projector head by being plugged into said power supply receptacle, said transparency projector comprising a light source, a holder for a transparency to be projected and a lens directed through an exit opening toward said base, whereby an image projected by said transparency projector on the base is re-projected by said projector head onto a vertical surface.

An overhead projector system comprising a conference table having a table top, a plurality of sockets in said table top with electrical contacts in each socket, a plurality of overhead projectors each comprising a hollow post having a lower end which fits in a socket in said table top so that said post extends up from said table top, a projector head on an upper portion of said post and comprising a light source and an objective lens, a power supply unit in said post supplying power to said light source, and electrical contacts at said lower end of said post, said contacts being connected with said power supply unit and adapted to engage said contacts in said socket when said post is plugged into said socket.

An overhead projector comprising a base, a hollow support comprising three sections disposed at obtuse angles to one another, namely a lower approximately vertical section extending up from said base, an upper approximately horizontal section above the base and an intermediate inclined section connecting said upper section with said lower section, an objective lens holder with a lens therein mounted on a free end of said upper section, a light source in said upper section, a power supply unit in said lower section and a power driven ventilator in said intermediate section;

• said hollow support having an air outlet opening in said intermediate section of said hollow support adjacent said ventilator for discharge of air from said ventilator, a first air inlet in said lower section of said hollow support below said power supply unit for admitting air to cool said power supply unit and a second air inlet in said upper section of said hollow support adjacent said light source for admitting air to cool said light source, air from said first and second inlets being drawn over said power supply unit and said light source respectively by said ventilator and discharged through said outlet opening.

An overhead projector comprising a base, a hollow post extending up from said base, a projector head on an upper portion of said post and comprising a housing having an opening in a side wall thereof, a lamp holder comprising a rectangular frame having a handle portion at one side and electrical plug-in connections at an opposite side, said frame being removable insertable through said opening into said projector head, a lamp socket in said frame and a lamp in said socket, said lamp holder being removable from said projector head for changing said lamp, an objective lens and a deflection mirror mounted on said housing, a power supply unit in a lower portion of said hollow post and supplying power for said lamp, a motor driven ventilator in said hollow post between said power supply unit and said projector head, said power supply unit also supplying power to said ventilator, an air outlet opening in said post for discharge of air from said ventilator and air inlets for admitting air to cool said power supply and said lamp, said air being drawn in over said power supply unit and said lamp by said ventilator and discharged through said outlet opening.

An overhead projector comprising a base, a hollow post extending up from said base, a projector head on an upper portion of said post and comprising a light source, an objective lens and a deflecting mirror, said light source comprising a lamp holder removably insertable in said projector head, two lamp sockets in said lamp holder and two lamps in said sockets, and electrical contacts disposed asymmetrically on said lamp holder engageable with counter contacts in said projector housing so as to light only one of said lamps at a time, a power supply PG,45 unit in a lower portion of said hollow post and supplying power for said light source, a motor driven ventilator in said hollow post between said power supply unit and said light source, said power supply unit supplying power to said ventilator, an air outlet opening in said post for discharge of air from said ventilator and air inlets for admitting air to cool said power supply unit and said light source, said air being drawn over said power supply unit and said light source by said ventilator and discharged through said outlet opening.