Spring-loaded mechanical seal with torque control

Claim 2

Mechanical seal apparatus for sealing a rotary shaft to a housing having an opening through which the shaft extends comprising: a stationary sealing ring, means for mounting said stationary sealing ring on the housing, a rotary sealing ring, means for mounting said rotary sealing ring on the shaft for limited axial and limited rotational shifting movements thereon, said sealing rings having complemental, opposed radial sealing faces, resilient means for applying a biasing force to said rotary sealing ring for urging it axially into sealing relationship with said stationary sealing ring, and means associated with said resilient means and responsive to the torque produced by the drag between said sealing rings upon their relative rotation in either direction for applying to said resilient means a force opposed to said biasing force to urge said rotary sealing ring away from said stationary sealing ring, said means associated with said resilient means including first cooperating cam means carried by said shaft and said rotary sealing ring and responsive to rotational shifting of said rotary sealing ring on the shaft for producing said force opposed to said biasing force upon relative rotation of said sealing rings in one direction, and second cooperating cam means carried by said shaft and said rotary sealing ring and responsive to rotational shifting of said rotary sealing ring on the shaft for producing said force opposed to said biasing force upon relative rotation of said sealing rings in the opposite direction.

Claim 3

Mechanical seal apparatus as defined in claim 1, wherein said first cooperating cam means includes a first cam member and means for fixedly mounting said first cam member on the shaft, said second cooperating cam means includes a second cam member and means for mounting said second cam member on said rotary sealing ring, first cooperating cam surfaces on said cam members adapted to shift said rotary sealing ring away from said stationary sealing ring responsive to rotation in a given direction of said rotary sealing ring relative to said first cam member, and second cooperating cam surfaces on said cam members adapted to shift said rotary sealing ring axially away from said stationary sealing ring responsive to rotation in the opposite direction of said rotary sealing ring relative to said first cam member.

Claim 4

Mechanical seal apparatus as defined in claim 2 wherein one of said cam members comprises longitudinally extending cam slot means having opposite walls providing cam surfaces, and the other of said cam members comprises a longitudinally extending cam bar disposed in said slot means and providing cam surfaces on opposite sides thereof that cooperate with the cam surfaces provided by the walls of said cam slot means.

Claim 5

Mechanical seal apparAtus as defined in claim 3 wherein said cam surfaces of said cam slot means diverge in the rearward direction.

Claim 6

Mechanical seal apparatus as defined in claim 4 wherein said cam bar is a pivoted element of said second cam member, and the cam surfaces thereof are parallel to each other.

Claim 7

Mechanical seal apparatus as defined in claim 4 wherein said cam bar is a stationary element of said second cam member, and the cam surfaces thereof are parallel to the cam surfaces of said cam slot means.

Claim 8

Mechanical seal apparatus for sealing a rotary shaft to a housing having an opening through which the shaft extends including a stationary sealing ring, means for mounting said stationary sealing ring on the housing, a rotary sealing ring, means for mounting said rotary sealing ring on the shaft, said stationary and rotary sealing rings having complemental, opposed radial sealing faces, resilient means for applying a biasing force to said rotary sealing ring for urging it axially into sealing relationship with said stationary sealing ring, and means associated with said resilient means and responsive to the torque produced by the drag between said sealing rings upon their relative rotation for applying to said resilient means a force opposed to said biasing force, said last mentioned means comprising a first cam member, means for fixedly mounting said first cam member on the shaft, a second cam member, means for mounting said second cam member on the shaft for limited axial and limited rotational shifting movements thereon, slip joint means connecting said second cam member to said rotary sealing ring for rotation therewith and for axial shifting relative thereto, interengaging surfaces on said second cam member and on said rotary sealing ring for moving said rotary sealing ring into sealing relationship with said stationary sealing ring, said interengaging surfaces permitting said second cam member to move axially away from said rotary sealing ring, said resilient means comprising spring means compressed between said first cam member and said second cam member for biasing said second cam member and said rotary sealing ring into sealing relationship, and cooperating cam surfaces on said cam members adapted to shift said second cam member axially away from said rotary sealing ring responsive to rotation in a given direction of said second cam member relative to said first cam member to further compress said spring means.

Claim 9

Mechanical seal apparatus for sealing a rotary shaft to a housing having an opening through which the shaft extends including a stationary sealing ring, means for mounting said stationary sealing ring on the housing, a rotary sealing ring, means for mounting said rotary sealing ring on the shaft, said stationary and rotary sealing rings having complemental, opposed radial sealing faces, resilient means for applying a biasing force to said rotary sealing ring for urging it axially into sealing relationship with said stationary sealing ring, and means associated with said resilient means and responsive to the torque produced by the drag between said sealing rings upon their relative rotation for applying to said resilient means a force opposed to said biasing force, said last mentioned means comprising a first cam member, means for fixedly mounting said first cam member on the shaft, a second cam member, means for mounting said second cam member on the shaft for limited axial and limited rotational shifting movements thereon, slip joint means connecting said second cam member to said rotary sealing ring for rotation therewith and for axial shifting relative thereto, interengaging surfaces on said second cam member and on said rotary sealing ring for moving said rotary sealing ring into sealing relationship with said stationary sealing ring, said interengaging surfaces permitting said second cam member to move axially away from said rotary sealing ring, said resilient means comprising spring means compressed between said first cam member and said second cam member for biasing said second cam member and said rotary sealing ring into sealing relationship, and cooperating cam surfaces on said cam members adapted to shift said second cam member axially away from said rotary sealing ring responsive to rotation in a given direction of said second cam member relative to said first cam member to further compress said spring means.

Claim 10

Mechanical seal apparatus as defined in claim 7 wherein said cam members have second cooperating cam surfaces adapted to shift said second cam member axially away from said rotary sealing ring responsive to rotation in the opposite direction of said second cam member relative to said first cam member to further compress said spring means.

Claim 11

Mechanical seal apparatus as defined in claim 8 wherein said first cam member comprises longitudinally extending cam slot means having opposite walls providing cam surfaces, and said second cam member comprises a longitudinally extending cam bar disposed in said slot means and providing cam surfaces on opposite sides thereof that cooperate with the cam surfaces provided by the walls of said cam slot means.

Claim 12

Mechanical seal apparatus as defined in claim 9 wherein said cam surfaces of said cam slot means diverge in the rearward direction.

Claim 13

Mechanical seal apparatus as defined in claim 10 wherein said cam bar is a pivoted element of said second cam member, and the cam surfaces thereof are parallel to each other.

Claim 14

Mechanical seal apparatus as defined in claim 10 wherein said cam bar is a stationary element of said second cam member, and the cam surfaces thereof are parallel to the cam surfaces of said cam slot means.

Claim 15

Mechanical seal apparatus as defined in claim 7 including annular elastomeric gasket means carried by said rotary sealing ring for sealing said rotary sealing ring to the shaft, and wherein the interengaging surface on said rotary sealing ring comprises a surface on said gasket means.