Door hold open attachment for a door check

Claim 2

In a door check of the type which includes means defining a cylinder, a member slidable within said cylinder, resilient means biasing said member toward one end of said cylinder, means for connecting said door check to a door and frame combination to move said member relative to said cylinder against said biasing means upon opening said door, hydraulic fluid in said cylinder and means for permitting fluid flow counter to the movement of said member to restrain the movement of said door; a door holdopen mechanism comprising means providing an extension of said cylinder on that end thereof toward which said member is biased, a piston resiliently biased within said extension to follow said member and having a one way flow passage therein to admit fluid therethrough upon following movement against said resilient means, means closing said extension, said closing means including a passage having a valve seat therein for delivering fluid from the downstream side of said one way flow passage to the upstream side thereof, a valve for closing against said valve seat, and electrically actuated means for operating said valve.

Claim 3

The combination of claim 1 wherein said valve closes against said seat from the downstream side thereof.

Claim 4

The combination of claim 1 wherein said valve is energized with sufficient force to close against the pressure imposed by said resilient means but insufficient force to hold against a pressure in excess of that of said resilient means.

Claim 5

The combiNation of claim 2 wherein said valve is energized with sufficient force to close against the pressure imposed by said resilient means but insufficient force to hold against a pressure in excess of that of said resilient means.

Claim 6

The combination of claim 1 wherein said resilient means establishes a pressure on the fluid between said piston and said closing means, said valve has a face larger than said seat and said fluid delivery passage includes a valve chamber on the downstream side of said valve seat containing closely said valve, and said electrically actuated means is adapted to urge said valve against said seat with a force greater than the product of the pressure of said resilient means and the area of said valve seat and less than the product of the pressure of said resilient means and said valve face.

Claim 7

The combination of claim 1 wherein said valve is an elongated assembly having a face adapted to close on said seat and including additionally a thimble mounted in fluid-tight relationship to said cylinder defining means and containing the end of said valve assembly remote from said face, and magnetic valve operating means on the exterior of said thimble.

Claim 8

The combination of claim 1 wherein said fluid delivery passage includes a tube mounted in said closing means and extending through said piston throughout the range of movement thereof.

Claim 9

A combined door check and door hold open device including resilient means for urging a door toward closure upon expansion thereof, means defining a hydraulic cylinder, a piston therein connected to move toward one end of said cylinder with the expansion of said resilient means, said resilient means establishing a pressure per unit area on fluid ahead of said piston, means associated with said one end of said cylinder defining a passage for the escape of fluid from said one end having a valve seat therein, a valve adapted to close against said valve seat from the downstream side thereof, said valve having a face larger than said valve seat, a valve chamber downstream of said seat, a portion of said valve downstream of said face closely contained in said chamber to substantially prevent fluid flow past said valve and allow a pressure drop across said valve when said valve is open, means providing a fluid escape passage opening into said valve chamber upstream of said valve face at an open position of said valve, means providing a fluid escape passage from said valve chamber behind said closely contained portion of said valve when in said open position, and means adapted to hold said valve resiliently against said seat with a force in excess of the product of said pressure and said valve seat area and less than the product of said pressure and said face area.

Claim 10

A combined door check and door hold open device including resilient means for urging a door toward closure upon expansion thereof, means defining a hydraulic cylinder, a piston therein connected to move toward one end of said cylinder with the expansion of said resilient means, said resilient means establishing a pressure per unit area on fluid ahead of said piston, means associated with said one end of said cylinder defining a passage for the escape of fluid from said one end having a valve seat therein, a valve adapted to close against said valve seat from the downstream side thereof, said valve having a face larger than said valve seat, a valve chamber downstream of said seat, a portion of said valve downstream of said face closely contained in said chamber to substantially prevent fluid flow past said valve and allow a pressure drop across said valve when said valve is open, means providing a fluid escape passage opening into said valve chamber upstream of said valve face at an open position of said valve, means providing a fluid escape passage from said valve chamber behind said closely contained portion of said valve when in said open position, and means adapted to hold said valve resiliently against said seat with a force in excess of the product of said pressure and said valve seat area and less than the product of said pressure and said face area.

Claim 11

The combination of claim 8 wherein said means for resiliently holding said valve are electrically operated.