Screen extension linkage for a video real-screen projection apparatus

Claim 2

A video rear-screen projection apparatus, comprising: a housing accommodating a fixedly arranged cathode-ray tube unit which is provided with a projection lens and which is secured to a frame which, adjacent two opposite side walls of the housing, has two members in which a shaft coupled to a motor is journalled at its ends, which shaft carries a respective plate at each of its ends; a first mirror which extends in the direction of width of the housing and which is connected, at two opposite sides via pivots arranged approximately in alignment with a front side of the housing, to the side walls of the housing, the first mirror being pivotally linked by a bar at each of the two opposite sides to an associated one of the plates so that, in one position of the plates, the first mirror is located entirely inside the housing and, in another position of the plates, the first mirror is extended with its reflecting surface facing the projection lens; a transparent screen which extends in the direction of width of the housing and parallel to the front side of the housing and which is provided at each of two opposite sides with a pair of pivots which are located a certain distance above one another and which are connected by first and second bars which cross one another to a pivot on the frame and a pivot on an associated one of the plates, respectively, each of the first bars being provided between its ends with a pivot which is connected via a third bar to the associated one of the plates; and a second mirror supported between the second bars in such a manner that, upon rotation of the plates, the screen and the first and the second mirrors are extended so that light rays from the cathode-ray tube strike the transparent screen, while, in a folded condition of the apparatus, the screen and the first and the second mirrors are located inside the housing.

Claim 3

An apparatus as claimed in claim 1, wherein the apparatus in the folded condition has a front to back dimension of 42 cm.

Claim 4

An apparatus as claimed in claim 1, wherein the housing has an upper wall lying in a plane oriented substantially perpendicularly to the side walls, and wherein the screen when extended is located partly above the plane.

Claim 5

An apparatus as claimed in claim 3, wherein the apparatus when the screen and the first and the second mirrors are extended has a front to back dimension of 67 cm.

Claim 6

A screen extension linkage for an image projector, comprising a frame defining first, second and third pivot axes which are mutually parallel and perpendicular to a plane of symmetry, a mirror connected to said frame for pivotal movement about said first axis, said mirror being substantially perpendicular to said plane, a crank member connected to said frame for pivotal movement about said second axis between folded and projection positions, and comprising means for defining fourth and fifth pivot axes, perpendicular to said plane of symmetry, spaced from each other and from said second axis, and fixed in relative relationship to each other and to said second axis, a first rigid link connected to said frame for pivotal movement about said third axis, and comprising means for defining a sixth pivot axis perpendicular to said plane and spaced from said third axis, a second rigid link connected to said crank member for pivotal movement about said fourth axis, and comprising means for defining a seventh pivot axis perpendicular to said plane and spaced from said fourth axis, a screen connected to said first link for pivotal movement about said sixth axis and connected, at a location spaced from the sixth axis, to said second link for pivotal movement about said seventh axis, a third rigid link connected to said crank member for pivotal movement about said fifth axis and pivotally connected, at a location spaced from the fifth axis, to said first link at a location between said third and sixth axes, means for pivoting said mirror from an inside position to an extended projection position responsive to pivoting of said crank member from the folded position to the projection position, and means for projecting an image reflected by said mirror onto said screen when the crank member is in the projection position, said axes being arranged relative to each other such that in the crank projection position said screen is extended to a projection position, and in the crank folded position said screen is in a stowed inside position generally parallel to said screen projection position.

Claim 7

A screen extension linkage for an image projector, comprising a frame defining first, second and third pivot axes which are mutually parallel and perpendicular to a plane of symmetry, a mirror connected to said frame for pivotal movement about said first axis, said mirror being substantially perpendicular to said plane, a crank member connected to said frame for pivotal movement about said second axis between folded and projection positions, and comprising means for defining fourth and fifth pivot axes, perpendicular to said plane of symmetry, spaced from each other and from said second axis, and fixed in relative relationship to each other and to said second axis, a first rigid link connected to said frame for pivotal movement about said third axis, and comprising means for defining a sixth pivot axis perpendicular to said plane and spaced from said third axis, a second rigid link connected to said crank member for pivotal movement about said fourth axis, and comprising means for defining a seventh pivot axis perpendicular to said plane and spaced from said fourth axis, a screen connected to said first link for pivotal movement about said sixth axis and connected, at a location spaced from the sixth axis, to said second link for pivotal movement about said seventh axis, a third rigid link connected to said crank member for pivotal movement about said fifth axis and pivotally connected, at a location spaced from the fifth axis, to said first link at a location between said third and sixth axes, means for pivoting said mirror from an inside position to an extended projection position responsive to pivoting of said crank member from the folded position to the projection position, and means for projecting an image reflected by said mirror onto said screen when the crank member is in the projection position, said axes being arranged relative to each other such that in the crank projection position said screen is extended to a projection position, and in the crank folded position said screen is in a stowed inside position generally parallel to said screen projection position.

Claim 8

A projector as claimed in claim 5, wherein said screen projection position is a generally vertical position, and is higher than said stowed inside position.

Claim 9

A projector as claimed in claim 6, wherein in the inside position said screen overlaps and is outside of said mirror.

Claim 10

A projector as claimed in claim 7, comprising a housing within which said frame is mounted, said first pivot axis being adjacent a bottom surface of the housing and, in the stowed inside position, said screen, mirror, links and crank member being entirely disposed within the housing.

Claim 11

A projector as claimed in claim 8, wherein the projector comprises two said second links, and a second mirror supported between and fixed to said second links perpendicular to said plane of symmetry, and said means for projecting includes at least one projection element for directing light rays toward said first mirror, said rays being reflected from the first mirror to the second mirror and then to the screen when the crank member is in the projection position.

Claim 12

A projector as claimed in claim 9, wherein said at least one projection element includes a projection lens fixed to said frame.

Claim 13

A projector as claimed in claim 10, wherein said means for projecting further includes a cathode ray tube fixed to said frame.

Claim 14

A projector as claimed in claim 7, wherein the projector comprises two said second links, and a second mirror supported between and fixed to said second links perpendicular to said plane of symmetry, and said means for projecting includes at least one projection element for directing light rays toward said first mirror, said rays being reflected from the first mirror to the second mirror and then to the screen when the crank member is in the projection position.

Claim 15

A projector as claimed in claim 6, wherein the projector comprises two said second links, and a second mirror supported between and fixed to said second links perpendicular to said plane of symmetry, and said means for projecting includes at least one projection element for directing light rays toward said first mirror, said rays being reflected from the first mirror to the second mirror and then to the screen when the crank member is in the projection position.

Claim 16

A projector as claimed in claim 5, wherein the projector comprises two said second links, and a second mirror supported between and fixed to said second links perpendicular to said plane of symmetry, and said means for projecting includes at least one projection element for directing light rays toward said first mirror, said rays being reflected from the first mirror to the second mirror and then to the screen when the crank member is in the projection position.