Door closing apparatus

A door closing apparatus comprising:

• a housing, means defining a cylinder in said housing, a piston mounted for reciprocation in said cylinder and having a plurality of piston teeth formed thereon, a pinion mounted for rotation in said housing and having a plurality of circumferentially disposed pinion teeth engaging said piston teeth to actuate said piston in response to rotation of said pinion, linkage means for joining said door closing apparatus between a door and a door frame and including drive means engaging said pinion for rotating said pinion in response to opening and closing of said door, respectively, said piston comprising a tubular member having a closed end and an open end and biasing means for urging said piston in a predetermined direction, said biasing means comprising a first compression spring member and a second compression spring member of shorter uncompressed axial length than the first compression spring member and coaxially disposed in said piston therewith, an axially moveable stop member abutting an end of said first and second spring members remote from the closed end of said piston member and means for axially varying the position of said stop member for effecting a desired amount of compression of said first spring member against said piston member closed end and for selectively advancing said second spring member to effect either none or a desired degree of compression against said piston member closed end over the travel thereof during reciprocation, thereby providing means for selectively adjusting the biasing force supplied by said biasing means for urging said piston in said predetermined direction.

A door closing apparatus comprising a housing, a piston and a pinion mounted in said housing for reciprocation and rotation respectively, cooperating means on said piston and said pinion for reciprocating said piston in response to rotation of said pinion, and linkage means for joining said door closing apparatus between a door and a door frame, and comprising first and second elongate arm members, said first arm member having driveshaft means at one end thereof for engaging said pinion for rotation in unison therewith, and said second arm member having first and second ends and means in said first end defining substantially a ball joint for pivotally engaging an end of said first arm member opposite said driveshaft means, and means defining another ball joint at said second end for pivotal engagement with a mounting bracket to complete said joining of said apparatus between said door and frame, said last two mentioned means comprising through apertures in said first and second ends of said second arm member, each of said apertures defining an annular interior surface comprising a section of a sphere, and a pair of bearing members each having spherical external surface portions removeably engageable with said interior spherical surfaces, said bearing members having central openings for receiving a fastener therethrough to effect said pivotal engagement while retaining said bearing members in said openings.

A door closing apparatus comprising in combination:

• a housing comprising a casting member having a cylinder cored therein and a bore cored therethrough substantially perpendicular with said cylinder and intersecting said cylinder over a predetermined fractional portion of the volume thereof, a cylindrical piston mounted for reciprocal motion in said cylinder, a pinion rotatably mounted in said bore, cooperating teeth on said piston and said pinion engaged through said intersecting portions of said bore and cylinder for effecting reciprocation and rotation of said piston and pinion in unison, a bushing member interposed between said pinion and said bore and having a window disposed for permitting said engagement between said cooperating teeth, linkage means for joining said door closing apparatus between a door and a door frame and including first and second elongate arm members, said first arm member having driveshaft engaging said pinion and said second arm member having first and second ends, means in said first end defining substantially a ball joint for pivotally engaging an end of said first arm member opposite said drive shaft means, means defining a second ball joint in said second end for pivotal engagement with a mounting bracket to complete said joining between said door and door frame, means defining a closed end of said piston for dividing said cylinder into portions of varying volume in accordance with the reciprocation of said piston, and biasing means for urging said piston in a predetermined direction and comprising a pair of coaxially disposed compression spring members disposed in said cylinder and an axially movable stop member abutting one end of said pair of spring members, an opposite end of said pair of spring members abutting said closed end of said piston, said stop member effecting a desired amount of compression of first and second spring members in accordance with the axial position thereof, said housing being adapted for retaining a predetermined amount of fluid such as hydraulic oil therein, said door closing apparatus further including fluid flow control means comprising a plurality of port means and channel means in said housing, and valve means cooperating with said port means and channel means for selectively controlling fluid flow between opposite sides of said piston in response to opening and closing of said door, respectively.