Automatic door opening and shutting device

Claim 1

A device for opening and shutting a door, comprising a support having a lower tube and an upper tube vertically movable relative to the lower tube; a driving source mounted on the upper tube of the support; friction drive means for carrying out a friction drive of the door by transmitting power of the drive source and adapted to move clockwise or anticlockwise or to stop, the friction drive means having a friction wheel movable between a first position in which the friction wheel frictionally engages a friction surface of the door so that load is applied to the latter and a second position in which the friction wheel is disengaged from the friction surface of the door so that no load is applied to the latter, a pair of guide wheels for securing the friction wheel against shaking of the door caused during its opening and shutting and for thereby maintaining appropriate power transmission of the friction wheel to the friction surface, the friction wheel being disengageable from the friction surface of the door to a distance corresponding to the difference between the radii of the guide wheels and the radius of the friction wheel, and a power transmission means installed between a drive source and an output shaft for rotating the friction wheel with a given torque; means for moving the friction wheel at least from the first position to the second position in which the friction wheel is disengaged from the friction surface of the door so that no load is applied to the latter whereby to permit opening or shutting of the door by hand; guide rails for guiding a side of the door which is spaced from the friction surface thereof, during opening or shutting of the door; and stop means for stopping the opening or shutting movement of the door when a resistance force applied to the door surpasses the friction drive force transmitted by said friction wheel to the friction surface.

Claim 2

A device for opening and shutting a door, comprising a support having a lower tube and an upper tube vertically movable relative to the lower tube; a driving source mounted on the upper tube of the support; friction drive means for carrying out a friction drive of the door by transmitting power of the drive source and adapted to move clockwise or anticlockwise or to stop, the friction drive means having a friction wheel movable between a first position in which the friction wheel frictionally engages a friction surface of the door so that load is applied to the latter and a second position in which the friction wheel is disengaged from the friction surface of the door so that no load is applied to the latter, a pair of guide wheels for securing the friction wheel against shaking of the door caused during its opening and shutting and for thereby maintaining appropriate power transmission of the friction wheel to the friction surface, the friction wheel being disengageable from the friction surface of the door to a distance corresponding to the difference between the radii of the guide wheels and the radius of the friction wheel, and a power transmission means installed between a drive source and an output shaft for rotating the friction wheel with a given torque; means for moving the friction wheel at least from the first position to the second position in which the friction wheel is disengaged from the friction surface of the door so that no load is applied to the latter whereby to permit opening or shutting of the door by hand; guide rails for guiding a side of the door which is spaced from the friction surface thereof, during opening or shutting of the door; and stop means for stopping the opening or shutting movement of the door when a resistance force applied to the door surpasses the friction drive force transmitted by said friction wheel to the friction surface.

Claim 4

A device for opening and shutting a door having a part provided with an edge face which extends between two lateral faces, comprising friction drive means for frictionally moving a door between an open and a shut position, said drive means having a friction wheel rotatable about an axis extending across said edge face substantially transversely said lateral faces and said friction wheel being movable betwen a first position in which it is pressed against said edge face to thereby open or close said door by rotation of said friction wheel, and a second position in which it is disengaged from said edge face so that no load is applied to the door and the same can be easily opened or shut by hand; a pair of guide wheels spaced from one another along said axis and located at opposite axial sides of said friction wheel each adjacent the respective lateral face of the latter so as to prevent axial displacement of said friction wheel and to thereby suppress shaking of the door during opening and shutting of the latter; and a drive source for driving said friction drive means.

Claim 5

A device for opening and shutting a door having a part provided with an edge face which extends between two lateral faces, comprising friction drive means for frictionally moving a door between an open and a shut position, said drive means having a friction wheel rotatable about an axis extending across said edge face substantially transversely said lateral faces and said friction wheel being movable betwen a first position in which it is pressed against said edge face to thereby open or close said door by rotation of said friction wheel, and a second position in which it is disengaged from said edge face so that no load is applied to the door and the same can be easily opened or shut by hand; a pair of guide wheels spaced from one another along said axis and located at opposite axial sides of said friction wheel each adjacent the respective lateral face of the latter so as to prevent axial displacement of said friction wheel and to thereby suppress shaking of the door during opening and shutting of the latter; and a drive source for driving said friction drive means.