Ball-screw actuator with stop mechanism

Claim 2

A ball-screw actuator having a rotary nut and a nonrotary screw, means for imparting rotational movement to said nut for telescoping said nonrotating screw, stop means including an elongated shaft having radially extending tangs formed thereon and adapted to engage an abutment carried by said rotary nut, snubber means cooperatively operative with said elongated shaft to absorb the torsional energy transmitted when said tangs engage said abutment, means for rendering said stop means inoperative when said screw is in a first retracted stop position, and means for placing said tangs into engagement with said abutment when said screw is in a further retracted second stop position, such that the torsional energy is also absorbed by said snubber.

Claim 3

A ball-screw actuator as claimed in clAim 1 including another abutment or said screw axially spaced from said abutment carried by said nut adapted to engage said tangs when said screw is in an extended position, said snubber absorbing the torsional load when in said extended position when said tangs engage said other abutment.

Claim 4

A ball-screw actuator as claimed in claim 1 including first resilient means holding said elongated shaft in retractable relationship with said screw, and a second resilient means having a greater force than said first resilient means imposing a load on said screw to hold it in one direction, said means for rendering said stop inoperative including a plunger adapted to engage said second resilient means to prevent said tangs from engaging said abutment and permit said screw to be further retracted and engage said tangs until said force of said first resilient means permits said elongated shaft to position axially to overcome the force of said second resilient means so that said tangs engage said abutment.

Claim 5

A ball-screw actuator as claimed in claim 3 wherein said first and second resilient means are helically wound coil springs.

Claim 6

A ball-screw actuator as claimed in claim 3 including a solenoid actuating said plunger in and out of engagement with said second resilient means.

Claim 7

A ball-screw actuator having a casing supporting a rotary nut and a nonrotary screw, means for imparting rotational movement to said nut for telescoping said nonrotating screw, stop means including an elongated shaft extending concentrically with and disposed in an opening formed in said nut and having radially extending tangs formed thereon, an abutment carried on the inner diameter of said rotary nut adapted to contact said tangs, snubber means cooperatively operative with said elongated shaft to absorb the torsional energy transmitted when said tangs engage said abutment, means for rendering said stop means inoperative when said screw is in a first retracted stop position, means for placing said tangs into engagement with said abutment when said screw is in a further retracted second stop position, such that the torsional energy is also absorbed by said snubber, said means for rendering said stop means inoperative including a first spring for loading said elongated shaft in one direction, a second spring having a force lighter than said first spring loading said shaft in an opposite direction, a solenoid adapted to place said first spring in the loaded position such that said tangs remain out of engagement when said screw goes beyond the first retracted stop position and overcomes the force of said second spring and overcomes the force of the first spring to allow the tangs to engage said abutment at the second stop position.

Claim 8

A ball-screw actuator having a casing supporting a rotary nut and a nonrotary screw, means for imparting rotational movement to said nut for telescoping said nonrotating screw, stop means including an elongated shaft extending concentrically with and disposed in an opening formed in said nut and having radially extending tangs formed thereon, an abutment carried on the inner diameter of said rotary nut adapted to contact said tangs, snubber means cooperatively operative with said elongated shaft to absorb the torsional energy transmitted when said tangs engage said abutment, means for rendering said stop means inoperative when said screw is in a first retracted stop position, means for placing said tangs into engagement with said abutment when said screw is in a further retracted second stop position, such that the torsional energy is also absorbed by said snubber, said means for rendering said stop means inoperative including a first spring for loading said elongated shaft in one direction, a second spring having a force lighter than said first spring loading said shaft in an opposite direction, a solenoid adapted to place said first spring in the loaded position such that said tangs remain out of engagement when said screw goes beyond the first retracted stop position and overcomes the force of said second spring and overcomes the force of the first spring to allow the tangs to engage said abutment at the second stop position.

Claim 9

A ball-screw actuator having a pair of cooperating members being disposed for relative rotation, means for imparting rotational movement to one of said members for telescoping the other of said members which is held in a nonrotating positon, stop means including an elongated shaft having radially extending tangs formed thereon and adapted to engage an abutment carried by said rotating member, snubber means cooperatively operative with said elongated shaft to absorb the torsional energy transmitted when said tangs engage said abutment, means for rendering said stop means inoperative when said nonrotating member is in a first retracted stop position, and means for placing said tangs into engagement with said abutment when said nonrotating member is in a further retracted second stop position, such that the torsional energy is also absorbed by said snubber.

Claim 10

A ball-screw actuator having a pair of cooperating members being disposed for relative rotation, means for imparting rotational movement to one of said members for telescoping the other of said members which is held in a nonrotating positon, stop means including an elongated shaft having radially extending tangs formed thereon and adapted to engage an abutment carried by said rotating member, snubber means cooperatively operative with said elongated shaft to absorb the torsional energy transmitted when said tangs engage said abutment, means for rendering said stop means inoperative when said nonrotating member is in a first retracted stop position, and means for placing said tangs into engagement with said abutment when said nonrotating member is in a further retracted second stop position, such that the torsional energy is also absorbed by said snubber.