Hand-held film projectors

Claim 1

In a hand-held projector for projecting onto a given surface a series of images derived from a series of transparencies carried by a film strip, comprising hollow casing means having a pair of opposed side walls and an endless peripheral wall extending between and interconnecting said side walls and defining therewith a hollow interior of said casing means, said peripheral wall having opposed front and rear portions and opposed longitudinal portions extending between interconnecting said front and rear portions, said front portion of said peripheral wall having opposed ends and carrying substantially midway between said opposed ends an objective means having an optical axis extending substantially midway between said longitudinal portions of said peripheral wall for projecting onto said surface an image of a transparency situated in said casing means behind said objective means along said optical axis thereof, said casing means carrying in its interior a film-guide wall extending substantially perpendicularly to said side walls between the latter as well as substantially perpendicularly to said longitudinal portions of said peripheral wall, said film-guide wall having a front surface directed toward said front portion of said peripheral wall and adapted to engage and guide a film strip, and said casing means having to the rear of said film-guide wall and extending along said opposed longitudinal portions of said peripheral wall and said rear wall in the interior of said casing means a film-guide means for guiding a film strip along said film-guide wall and along said longitudinal wall portions and rear portion of said peripheral wall in the interior of said casing means, said film-guide wall being formed with an opening through which said optical axis extends, and said casing means carrying in its interior behind said film-guide wall a light source situated along said optical axis in alignment with said opening of said film-guide wall and on opposite sides of said light source a pair of batteries each extending between said film guide wall and said rear portion of said peripheral wall, one of said longitudinal wall portions of said peripheral wall being formed with a slot through which film is introduced to move along said film-guide wall and along said film guide means, one of said longitudinal portions of said peripheral wall being formed with an opening, and a manually operable film-advancing means extending through the latter opening into the interior of said casing means and being accessible at the exterior or said casing means at the region of the latter opening, said film-advancing means being situated between said film-guide wall and said objective means and cooperating with said film-guide wall for guiding the film strip, spring means situated in said casing means for urging said film-advancing means to an outer position, one of said side walls being formed with an opening and said film-advancing means having a springy pawl portion engaging an edge of the latter opening of said one side wall for maintaining said film-advancing means in an inner rest position in opposition to the force of said spring means, said film-advancing means having a film-advancing tooth for extending into a perforation of the film strip for advancing the latter during manual movement of said film-advancing means from said outer to said inner position thereof, said film-guiding wall carrying a tooth engating a perforation of the film strip to prevent the latter from moving with said film-advancing means when the latter is urged to its outer position by said spring means, and conductor means carried by said casing means in the interior thereof and electrically connected with the batteries and the light-source means for electrically connecting the batteries and light-source means into a circuit, said conductor means having portions forming a switch means for closing said circuit, said switch means having a normally closed position for energizing the light source means from the batteries, and said film-advancing means having a projection cooperating with said switch means for opening the latter and opening the circuit for deenergizing the light source means when the springy pawl of said film-advancing means engages said edge of said opening of said one side wall to maintain said film-advancing means at said inner position thereof in opposition to said spring means, whereby upon manual movement of said pawl of said film-advancing means away from said edge of said opening of said one side wall, said spring means displaces said film-advancing means to said outer position thereof whereupon said switch means closes to energize said light-source means for providing light traveling along the optical axis through said opening in said film guide means, said film-advancing means also being formed with an opening, and the latter opening being aligned with said opening of said film-guide means and situated along said optical axis only when said film-advancing means is in said outer position thereof, so that release of said film-advancing means to be moved by said spring means to said outer position thereof will result in projection of an image from a transparency aligned with the aligned openings of said film-guide means and said film-advancing means, while manual movement of said film-advancing means back to said inner position thereof will advance the next transparency into a position to be projected while a wall portion of said film-advancing means will cover said opening of said film-guide means to prevent the next transparency from having its image projected until the film-advancing means is returned by the spring means to said outer position thereof.