Valve improvements

Claim 2

In a valve having a housing with a bore in which a cylindrical valve spool is slidably mounted for reciprocal movement, the improvement comprising: a. said housing having pilot and vent port means communicating with said bore at a first location; b. said housing having inlet port means communicating with said bore at a second location spaced axially of the bore from said first location; c. said valve spool having an annular formation with a diameter slightly less than the diameter of an adjacent portion of said bore thereby to provide free sliding movement between said formation and such adjacent portion of the bore, said formation defining first and second axially spaced valve spool surfaces exposed respectively to the spaces in said bore which are in communication with said inlet port means and said pilot and vent port means; d. said formation having an annular groove between said first and second valve spool surfaces; and e. a split ring of substantially nondeformAble cross section formed of a material having a low coefficient of friction with respect to metal loosely mounted in said groove and engaging the wall of said bore which constitutes said adjacent portion thereof in such a manner as to define a partial seal between said valve spool formation and said bore, said partial seal together with said low-friction engagement of said ring with said bore providing for low-energy movement of said valve spool and permitting a generally annular orifice to be formed between said ring and said bore during operation of said valve spool for controlling the pressure drop across said formation.

Claim 3

The improvement according to claim 1 wherein said ring is formed of a nylon material.

Claim 4

The improvement according to claim 1 wherein said ring is formed of a Teflon material.

Claim 5

The improvement according to claim 1 wherein said pilot and vent port means is defined by: a. a port communicating with said bore; b. a pilot valve for alternately communicating said port with a source of fluid pressure and with atmosphere; c. said pilot valve including a movable valve element and a cooperating seat element on the vent side of the pilot valve, a vent orifice being defined when said valve element is unseated; and d. the effective area of said vent orifice being substantially greater than the effective area of said annular orifice.

Claim 6

The improvement according to claim 4 further defined by: a. a stem connected at one end thereof to said pilot valve element; and b. a solenoid connected to said stem through the medium of a spring thereby to permit closing of the solenoid irrespective of the amount of movement of said stem.

Claim 7

In a valve having a housing with a bore in which a cylindrical valve spool is slidably mounted for reciprocal movement, the improvement comprising: a. said housing having pilot and vent port means communicating with said bore at one end thereof; b. said housing having inlet port means communicating with said bore at a location spaced axially of the bore from said one end of said bore; c. said valve spool having an annular formation in the form of a piston head on the end of said valve spool which is adjacent said one end of the bore and which has a diameter slightly less than the diameter of an adjacent portion of said bore thereby to provide free sliding movement between said formation and such adjacent portion of the bore, said formation defining first and second oppositely disposed valve spool surfaces exposed respectively to the spaces in said bore which are in communication with said inlet port means and said pilot and vent port means; d. said formation having an annular groove between said first and second valve spool surfaces; e. a ring formed of a material having a low coefficient of friction with respect to metal mounted in said groove an engaging the wall of said bore which constitutes said adjacent portion thereof so as to define a partial seal between said valve spool formation and said bore, whereby said ring constitutes an annular orifice between said inlet port means and said pilot and vent port means for controlling the pressure drop across said annular formation; and f. a resilient annular member on said piston head and arranged to sealingly engage said one end of said bore for closing said pilot and vent port means and for cushioning the valve spool as it completes its path of travel in a direction toward said one end of said bore.

Claim 8

In a valve having a housing with a bore in which a cylindrical valve spool is slidably mounted for reciprocal movement, the improvement comprising: a. said housing having pilot and vent port means communicating with said bore at one end thereof; b. said housing having inlet port means communicating with said bore at a location spaced axially of the bore from said one end of said bore; c. said valve spool having an annular formation in the form of a piston head on the end of said valve spool which is adjacent said one end of the bore and which has a diameter slightly less than the diameter of an adjacent portion of said bore thereby to provide free sliding movement between said formation and such adjacent portion of the bore, said formation defining first and second oppositely disposed valve spool surfaces exposed respectively to the spaces in said bore which are in communication with said inlet port means and said pilot and vent port means; d. said formation having an annular groove between said first and second valve spool surfaces; e. a ring formed of a material having a low coefficient of friction with respect to metal mounted in said groove an engaging the wall of said bore which constitutes said adjacent portion thereof so as to define a partial seal between said valve spool formation and said bore, whereby said ring constitutes an annular orifice between said inlet port means and said pilot and vent port means for controlling the pressure drop across said annular formation; and f. a resilient annular member on said piston head and arranged to sealingly engage said one end of said bore for closing said pilot and vent port means and for cushioning the valve spool as it completes its path of travel in a direction toward said one end of said bore.

Claim 9

The improvement according to claim 6 wherein said ball is formed of an elastomer material.

Claim 10

The improvement according to claim 1 further defined by: a. a first formation defined by an exterior portion of said valve spool; b. a second formation defined by an adjacent portion of the wall of said bore; c. one of said first and second formations having an annular groove therein; d. an O-ring in said groove; e. the other of said first and second formations having an aNnular surface defined by a cylindrical wall, an annular lip having its cross section at a radius and a tapered wall between said cylindrical wall and said lip and adjoining the former and the latter; and f. said O-ring being in sealing engagement with said tapered wall when said valve spool is in one position defining its limit of movement in one direction, said O-ring being in spaced relation with said tapered wall and nearer said lip than said cylindrical wall when said valve spool is in another position defining its limit of movement in the other direction, whereby frictional engagement between said O-ring and said tapered wall is substantially minimized.

Claim 11

In a valve having a housing with a bore in which a cylindrical valve spool is slidably mounted for reciprocal movement, the improvement comprising: a. said housing having a pilot and vent port communicating with said bore at a first location; b. said housing having inlet port means communicating with said bore at a second location spaced axially of the bore from said first location; c. said valve spool having an annular formation with a diameter slightly less than the diameter of an adjacent portion of said bore thereby to provide free sliding movement between said formation and such adjacent portion of the bore, said formation defining first and second oppositely disposed valve spool surfaces exposed respectively to the spaces in said bore which are in communication with said inlet port means and said pilot and vent port; d. said formation having an annular groove between said first and second valve spool surfaces; e. a ring formed of a material having a low coefficient of friction with respect to metal mounted in said groove and engaging the wall of said bore which constitutes said adjacent portion thereof so as to define a partial seal between said valve spool formation and said bore, whereby said ring constitutes an annular orifice between said inlet port means and said pilot and vent port for controlling the pressure drop across said formation; f. a pilot valve for alternately communicating said pilot and vent port with a source of fluid pressure and with atmosphere; g. said pilot valve including a movable valve element and a cooperating seat element on the vent side of the pilot valve, a vent orifice being defined when said valve element is unseated; h. the effective area of said vent orifice being substantially greater than the effective area of said annular orifice; i. a stem connected at one end thereof to said pilot valve element; j. a solenoid connected to said stem through the medium of a spring thereby to permit closing of the solenoid irrespective of the amount of movement of said stem; k. an enlarged formation on said one end of said stem; l. a collar on said stem in closely spaced relation with said enlarged formation; and m. said valve element being in the form of a ball made of yieldable material and having a blind bore with said enlarged formation and an adjacent portion of the stem snugly received therein, said collar engaging said ball adjacent the open end of said blind bore therein.

Claim 12

In a valve having a housing with a bore in which a cylindrical valve spool is slidably mounted for reciprocal movement, the improvement comprising: a. said housing having a pilot and vent port communicating with said bore at a first location; b. said housing having inlet port means communicating with said bore at a second location spaced axially of the bore from said first location; c. said valve spool having an annular formation with a diameter slightly less than the diameter of an adjacent portion of said bore thereby to provide free sliding movement between said formation and such adjacent portion of the bore, said formation defining first and second oppositely disposed valve spool surfaces exposed respectively to the spaces in said bore which are in communication with said inlet port means and said pilot and vent port; d. said formation having an annular groove between said first and second valve spool surfaces; e. a ring formed of a material having a low coefficient of friction with respect to metal mounted in said groove and engaging the wall of said bore which constitutes said adjacent portion thereof so as to define a partial seal between said valve spool formation and said bore, whereby said ring constitutes an annular orifice between said inlet port means and said pilot and vent port for controlling the pressure drop across said formation; f. a pilot valve for alternately communicating said pilot and vent port with a source of fluid pressure and with atmosphere; g. said pilot valve including a movable valve element and a cooperating seat element on the vent side of the pilot valve, a vent orifice being defined when said valve element is unseated; h. the effective area of said vent orifice being substantially greater than the effective area of said annular orifice; i. a stem connected at one end thereof to said pilot valve element; j. a solenoid connected to said stem through the medium of a spring thereby to permit closing of the solenoid irrespective of the amount of movement of said stem; k. an enlarged formation on said one end of said stem; l. a collar on said stem in closely spaced relation with said enlarged formation; and m. said valve element being in the form of a ball made of yieldable material and having a blind bore with said enlarged formation and an adjacent portion of the stem snugly received therein, said collar engaging said ball adjacent the open end of said blind bore therein.