Abstract: A positive displacement roots blower can include a housing having an inlet structured to receive an incoming flow of a fluid, an outlet structured to receive an outgoing flow of the fluid, and a passage. The positive displacement roots blower can also include a pair of intermeshed rotating members supported for complementary rotation within the housing, where the rotating members and the housing form respective operating volumes there between which rotate with the rotating members. Each of the respective operating volumes has the following regions: (1) open to inlet/closed to outlet; (2) closed to inlet/closed to outlet; and (3) closed to inlet/open to outlet. The passage includes a restriction and connects to at least one of the operating volumes when the at least one of the respective operating volumes is in region (2). The restriction can be a venturi feedback connecting to the outlet.

Abstract: A vacuum roots blower includes a rotor capable of being rotated to capture a gas from an inlet and further rotated to discharge the captured gas from an outlet. The captured gas is held within a pocket formed between lobes of the rotor and the adjacent housing within which the rotor is rotated. The vacuum roots blower includes a pressure relief system capable of delivering a pressure relief gas to the pocket. The pressure relief system includes a sonic passage structured to produce a choked flow condition as the pressure relief system fills the pocket with pressure relief gas. In one form the pressure relief gas can be a cooling gas, but other forms such as ambient air are also contemplated.

Abstract: A vacuum roots blower includes a rotor capable of being rotated to capture a gas from an inlet and further rotated to discharge the captured gas from an outlet. The captured gas is held within a pocket formed between lobes of the rotor and the adjacent housing within which the rotor is rotated. The vacuum roots blower includes a pressure relief system capable of delivering a pressure relief gas to the pocket. The pressure relief system includes a sonic passage structured to produce a choked flow condition as the pressure relief system fills the pocket with pressure relief gas. In one form the pressure relief gas can be a cooling gas, but other forms such as ambient air are also contemplated.

Abstract: A mortise lock for mounting in a door opposite a strike plate secured in a door jamb. A turn piece is connected to a thumb turn which is rotatable to a predetermined first or predetermined second position for an electronic or a magnetic recognition. The thumb turn manually locks the deadbolt in a dead bolt armed retracted position. A trigger bolt mechanism is provided for operative contact with a latch bolt arresting mechanism.

Abstract: The present invention relates to electronic door locks, and more particularly to an override mechanism for unlatching an electronic door mortise lock from an electronically controlled locked side when it cannot be unlocked electronically. The override mechanism comprises an interior drive mechanism connected to a door handle input hub of the unlocked side, for driving the door handle input hub from a closed position to an open position, and a locking mechanism adapted to actuate the interior drive mechanism.

Abstract: A door lock assembly which includes an electronic card reader is provided whereby when the clutch assembly is in the activated position, rotational movement of the outside handle is transmitted by way of a spindle through the mortise and through the clutch assembly to a clutch disk disposed between the mortise and clutch assemblies and the inside housing. The clutch disk is disposed inside the door. Rotational movement of the clutch disk is then imparted back towards the door through a drive disk and hub drive to the mortise latch hub which is disposed in the mortise housing disposed inside the door structure. As a result, the clutch disk and clutch assembly can be disposed between the inside housing and the inside door surface and the electronic components of the card reader and clutch assembly can be conveniently housed in the inside housing assembly.

Abstract: A door lock comprises a driver hub connected to a door lever, a driven hub, a latch lever movable by the driven hub for retracting the lock's bolt to open the lock, and a catch mechanism for selectively connecting the driver hub to the driven hub. The catch mechanism includes an idle position in which the driver hub moves without moving the driven hub and an engaged position in which the driver hub moves the driven hub and thus the lever and the bolt. A state selection mechanism is provided to displace the catch mechanism between its idle and engaged positions. An actuating mechanism, e.g. a solenoid, selectively positions the state selection mechanism such that the latter causes the catch mechanism, when driven by the driver hub, to adopt one of its idle and engaged positions such that the catch mechanism respectively drives, or not, the driven hub.