Linear actuator with locking means

Claim 2

In a device for shifting a projectable member linearly to a projected position and a retracted position, a mechanism to achieve said shifting and to lock said mechanism in the projected position comprising: a. a movable body carrying said projectable member, b. a housing for guiding said body in a lineal path between a first position and a second position, c. a first means in said body movable laterally of said lineal path between a retracted and a projected position to mechanically engage said housing in a projected position, d. cam means engageable with said first means upon movement of said first means from a projected position to a retracted position to exert a high retracting force on said body, and e. a reaction member movable in said body member in the directions of said lineal path, engageable at one end with a cam surface on said first means and engageable at the other end with a portion of said housing.

Claim 3

In a device for shifting a projectable member linearly to a projected position and a retracted position, a mechanism to achieve said shifting and to lock said mechanism in the projected position comprising: a. a first piston carrying said projectable member, b. a cylinder housing with fluid pressure ports at each end having said first piston slidably received therein for guiding said piston in a lineal path between a first position and a second position, c. a first means in said first piston movable laterally of said lineal path between a retracted and a projected position to mechanically engage said cylinder housing in A projected position, d. cam means engageable with said first means upon movement of said first means from a projected position to a retracted position to exert a high retracting force on said piston, e. a second piston axially displaceable relative to said first piston by fluid pressure, and f. a shaft on said second piston projecting into said first piston, said shaft carrying said cam means engageable with said first means to shift it laterally between said projected and retracted positions.

Claim 4

In a device for shifting a projectable member linearly to a projected position and a retracted position, a mechanism to achieve said shifting and to lock said mechanism in the projected position comprising: a. a first piston carrying said projectable member, b. a cylinder housing with fluid pressure ports at each end having said first piston slidably received therein for guiding said piston in a lineal path between a first position and a second position, c. a first means in said first piston movable laterally of said lineal path between a retracted and a projected position to mechanically engage said cylinder housing in A projected position, d. cam means engageable with said first means upon movement of said first means from a projected position to a retracted position to exert a high retracting force on said piston, e. a second piston axially displaceable relative to said first piston by fluid pressure, and f. a shaft on said second piston projecting into said first piston, said shaft carrying said cam means engageable with said first means to shift it laterally between said projected and retracted positions.

Claim 5

A device as defined in claim 2 in which said first means comprises a cross block slidable in said body having a cam slot on one side to engage a cam surface on said shaft, and a cam surface on an opposite side to engage said cam means.

Claim 6

A device as defined in claim 3 in which said cam means comprises a reaction plunger movable in said body in the direction of said lineal path, engageable at one end with said cam surface on said cross block and at the other end with a portion of said housing.

Claim 7

In a device for shifting a projectable member linearly to a projected position and a retracted position, a mechanism to achieve said shifting, to releasably lock said projectable member and to exert a high breakaway retracting force on said projectable member comprising, a housing adapted to guide the projectable member in a generally lineal path between projected and retracted positions with respect to said housing, driving means for shifting said projectable member to said projected and retracted positions, a first means movable by said driving means to bear on said housing to retain said projectable member in said projected position and to disengage said housing and release said projectable member, and a second means operably connected with said driving means and said projectable member, said second means providing a mechanical advantage such that the total breakaway retracting force exerted on said projectable member is greater than the force produced by said driving means on said projectable member when said projectable member was moved to said projectable position by said driving means at least as said projectable member initially moves from said projected position toward said retracted position.

Claim 8

In a device for shifting a projectable member linearly to a projected position and a retracted position, a mechanism to achieve said shifting, to releasably lock said projectable member and to exert a high breakaway retracting force on said projectable member comprising, a housing adapted to guide the projectable member in a generally lineal path between projected and retracted positions with respect to said housing, driving means for shifting said projectable member to said projected and retracted positions, a first means movable by said driving means to bear on said housing to retain said projectable member in said projected position and to disengage said housing and release said projectable member, and a second means operably connected with said driving means and said projectable member, said second means providing a mechanical advantage such that the total breakaway retracting force exerted on said projectable member is greater than the force produced by said driving means on said projectable member when said projectable member was moved to said projectable position by said driving means at least as said projectable member initially moves from said projected position toward said retracted position.

Claim 9

A device as defined in claim 5 wherein said housing comprises a cylinder housing and said driving means comprises a fluid actuated piston slidably received in said cylinder housing for generally axial movement between a first position wherein the projectable member is retracted and a second axially spaced position wherein the projectable member is extended.

Claim 10

A device as defined in claim 6 wherein said second means comprises cam means.

Claim 11

In a device for shifting a projectable member linearly to a projected position and a retracted position, a mechanism to achieve said shifting, to releasably lock said projectable member and to exert a high breakaway retracting force on said projectable member comprising, a cylinder housing, said housing being adapted to guide the projectable member in a generally lineal path between projected and retracted positions with respect to said housing, a fluid actuated first piston slidably received in said cylinder housing for generally axial movement for shifting said projectable member to said projected and retracted positions, a first means movable by said first piston to bear on said housing to retain said projectable member in said projected position and to disengage said housing and release said projectable member, a second means operably connected with said first piston and said projectable member, said second means providing a mechanical advantage greater than unity in exerting a higher breakaway retracting force on said projectable member than the force produced by said first piston, said second means exerting said higher breakaway retracting force at least as said projectable member initially moves from said projected position toward said retracted position, a movable body received in said cylinder housing and carryiNg said projectable member, and said first means comprises a cross member carried by said body and movable laterally of said lineal path of said body to an extended position to bear on said cylinder housing and to a retracted position to disengage from said cylinder housing.

Claim 12

In a device for shifting a projectable member linearly to a projected position and a retracted position, a mechanism to achieve said shifting, to releasably lock said projectable member and to exert a high breakaway retracting force on said projectable member comprising, a cylinder housing, said housing being adapted to guide the projectable member in a generally lineal path between projected and retracted positions with respect to said housing, a fluid actuated first piston slidably received in said cylinder housing for generally axial movement for shifting said projectable member to said projected and retracted positions, a first means movable by said first piston to bear on said housing to retain said projectable member in said projected position and to disengage said housing and release said projectable member, a second means operably connected with said first piston and said projectable member, said second means providing a mechanical advantage greater than unity in exerting a higher breakaway retracting force on said projectable member than the force produced by said first piston, said second means exerting said higher breakaway retracting force at least as said projectable member initially moves from said projected position toward said retracted position, a movable body received in said cylinder housing and carryiNg said projectable member, and said first means comprises a cross member carried by said body and movable laterally of said lineal path of said body to an extended position to bear on said cylinder housing and to a retracted position to disengage from said cylinder housing.

Claim 13

A device as defined in claim 8 in which said second means comprises a reaction member movable in said body generally in the direction of said lineal path thereof, engageable at one end with a cam surface of said first means, and engageable at the other end with a portion of said cylinder housing.

Claim 14

A device as defined in claim 8 in which said body has a passage extending generally linearly therein, and which also comprises an actuator shaft on said first piston and slidably received in said passage in said body and cam means on said actuator shaft and said cross member to effect lateral shifting of said cross member in response to relative movement between said actuator shaft and said body.

Claim 15

A device as defined in claim 8 in which said cylinder housing has fluid pressure ports at each end, said body comprises a second piston slidable in said cylinder housing and axially displaceable relative to said first piston by fluid under pressure, said body has a passage extending therein in the direction of said lineal path thereof, an actuator shaft on said first piston slidably received in said passage, and cam means on said actuator shaft and said cross member to shift said cross member laterally between retracted and extended positions in response to relative movement between said actuator shaft and said body.

Claim 16

A device as defined in claim 11 in which said cam means on said actuator shaft and said cross member comprises a cam slot on said cross member to engage a cam surface on said actuator shaft, and said second means comprises a cam surface on said cross member.

Claim 17

A device as defined in claim 12 in which said second means also comprises a reaction plunger movable in said body in the direction of said lineal path, engageable at one end with said cam surface on said cross member and at the other end with a portion of said cylinder housing.