Stop for screw and nut actuator

Claim 2

In an actuator assembly including a screw portion and a nut portion operatively associated with said screw portion in a manner whereby relative rotation therebetween effects concurrent relative bodily shiftable movement therebetween axially of said screw portion, the combination comprising, means defining a cylindrical surface on said screw portion, means defining an annular groove in said cylindrical surface disposed in a plane perpendicular to the axis of said screw portion, said groove having a pair of axially spaced lips at said cylindrical surface and continuous curvature therebetween to suppress the formation of stress concentrations in the area of said groove when a tensile force is applied to said screw portion at said groove, a stop member disposed in said groove and defining a shear section disposed generally between the lips of said groove and a raised portion projecting radially outwardly of said cylindrical surface, an intermediate means disposed between said stop member and said nut portion engageable on the latter and on said stop member generally at said shear section of the latter, said stop member through said intermediate means being operative to arrest relative axial bodily motion of said nut portion, and antifriction beAring means disposed between said intermediate means and said nut portion for dissipating relative rotation between the latter and said intermediate means.

Claim 3

In an actuator assembly including a screw portion and a nut portion operatively associated with said screw portion in a manner whereby relative rotation therebetween effects concurrent relative bodily shiftable movement therebetween axially of said screw portion, the combination comprising, means defining a cylindrical surface on said screw portion, means defining an annular groove in said cylindrical surface disposed in a plane perpendicular to the axis of said screw portion, said groove being semicircular in cross section and terminating at said cylindrical surface in a pair of axially spaced lips, the continuous curvature of said groove effectively suppressing the formation of stress concentrations in the area of said groove when said screw portion is subjected to tensile forces applied at said groove, an annular stop member having a circular cross section of diameter substantially equal to the width of said groove, said stop member being seated in said groove and defining an annular raised portion projecting radially outward of said cylindrical surface and a shear section disposed generally between the lips of said groove, an intermediate means disposed around said cylindrical surface between said raised portion and said nut portion engageable on the latter and on said raised portion generally at said shear section of said stop member, said stop member through said intermediate means being operative to arrest relative axial movement of said nut portion, and anti-friction bearing means disposed between said intermediate means and said nut portion operative to dissipate relative rotation between the latter and said intermediate means.

Claim 4

In an actuator assembly including a screw portion and a nut portion operatively associated with said screw portion in a manner whereby relative rotation therebetween effects concurrent relative bodily shiftable movement therebetween axially of said screw portion, the combination comprising, means defining a cylindrical surface on said screw portion, means defining an annular groove in said cylindrical surface disposed in a plane perpendicular to the axis of said screw portion, said groove being semicircular in cross section and terminating at said cylindrical surface in a pair of axially spaced lips, the continuous curvature of said groove effectively suppressing the formation of stress concentrations in the area of said groove when said screw portion is subjected to tensile forces applied at said groove, an annular stop member having a circular cross section of diameter substantially equal to the width of said groove, said stop member being seated in said groove and defining an annular raised portion projecting radially outward of said cylindrical surface and a shear section disposed generally between the lips of said groove, an intermediate means disposed around said cylindrical surface between said raised portion and said nut portion engageable on the latter and on said raised portion generally at said shear section of said stop member, said stop member through said intermediate means being operative to arrest relative axial movement of said nut portion, and anti-friction bearing means disposed between said intermediate means and said nut portion operative to dissipate relative rotation between the latter and said intermediate means.

Claim 5

In an actuator assembly including a screw portion and a nut portion operatively associated with said screw portion in a manner whereby relative rotation therebetween effects concurrent relative bodily shiftable movement therebetween axially of said screw portion, the combination comprising, means defining a cylindrical surface on said screw portion, means defining an annular groove in said cylindrical surface disposed in a plane perpendicular to the axis of said screw portion, said groove being semicircular in cross section and terminating at said cylindrical surface in a pair of axially spaced lips, the continuous curvature of said groove effectively suppressing the formation of stress concentrations in the area of said groove when said screw portion is subjected to tensile forces applied at said groove, an annular stop ring having a circular cross section of diameter substantially equal to the width of said groove, said stop ring being seated in said groove and defining an annular raised portion projecting radially outward of said cylindrical surface and a shear section disposed between the lips of said groove, means dividing said stop ring into a pair of identical semicircular half-ring segments for facilitating installation and removal of said stop ring from said screw portion, a cylindrical intermediate member disposed about said cylindrical surface and over said stop ring, means defining an inturned annular flange on said intermediate member closely slidably engaging said cylindrical surface and disposed between said raised portion and said nut portion, said annular flange being engageable on said nut portion and on said stop ring generally at said shear section of the latter, said stop ring through said inturned flange being operative to arrest relative axial movement of said nut portion, a keeper ring disposed within said intermediate member and around said stop ring for maintaining said half-ring segments in said groove, a retaining ring disposed on said intermediate member outboard of said keeper ring for retaining said keeper ring in said intermediate member, and anti-friction bearing means disposed between said intermediate member and said nut portion operative to dissipatE relative rotation between the latter and said intermediate member.

Claim 6

In an actuator assembly including a screw portion and a nut portion operatively associated with said screw portion in a manner whereby relative rotation therebetween effects concurrent relative bodily shiftable movement therebetween axially of said screw portion, the combination comprising, means defining a cylindrical surface on said screw portion, means defining an annular groove in said cylindrical surface disposed in a plane perpendicular to the axis of said screw portion, said groove being semicircular in cross section and terminating at said cylindrical surface in a pair of axially spaced lips, the continuous curvature of said groove effectively suppressing the formation of stress concentrations in the area of said groove when said screw portion is subjected to tensile forces applied at said groove, an annular stop ring having a circular cross section of diameter substantially equal to the width of said groove, said stop ring being seated in said groove and defining an annular raised portion projecting radially outward of said cylindrical surface and a shear section disposed between the lips of said groove, means dividing said stop ring into a pair of identical semicircular half-ring segments for facilitating installation and removal of said stop ring from said screw portion, a cylindrical intermediate member disposed about said cylindrical surface and over said stop ring, means defining an inturned annular flange on said intermediate member closely slidably engaging said cylindrical surface and disposed between said raised portion and said nut portion, said annular flange being engageable on said nut portion and on said stop ring generally at said shear section of the latter, said stop ring through said inturned flange being operative to arrest relative axial movement of said nut portion, a keeper ring disposed within said intermediate member and around said stop ring for maintaining said half-ring segments in said groove, a retaining ring disposed on said intermediate member outboard of said keeper ring for retaining said keeper ring in said intermediate member, and anti-friction bearing means disposed between said intermediate member and said nut portion operative to dissipatE relative rotation between the latter and said intermediate member.

Claim 7

In an actuator assembly including a screw portion and a nut portion operatively associated with said screw portion in a manner whereby relative rotation therebetween effects concurrent relative bodily shiftable movement therebetween axially of said screw portion, the combination comprising, means defining a cylindrical surface on said screw portion, means defining an annular groove in said cylindrical surface disposed in a plane perpendicular to the axis of said screw portion, said groove being semicircular in cross section and terminating at said cylindrical surface in a pair of axially spaced lips, the continuous curvature of said groove effectively suppressing the formation of stress concentrations in the area of said groove when said screw portion is subjected to tensile forces applied at said groove, means defining an annular stop ring having a circular cross section of diameter substantially equal to the width of said groove, said stop ring being seated in said groove and defining an annular raised portion projecting radially outward of said cylindrical surface and a shear section disposed between the lips of said groove, means dividing said stop ring into a pair of identical semicircular half-ring segments for facilitating installation and removal of said stop ring from said screw portion, an elongated cylindrical intermediate member disposed around said cylindrical surface and radially spaced therefrom, means defining an inturned annular flange on said intermediate member closely slidably received on said cylindrical surface and engageable on said nut portion, said flange and said intermediate member defining an annular chamber closed at one end and extending over said stop ring, an annular abutment ring closely slidably received on said cylindrical surface in said annular chamber inboard of said stop ring, said abutment ring being engageable on said stop ring generally at said shear section of the latter, a plurality of annular elastically deformable compression rings disposed in said chamber between said abutment ring and said annular flange, said stop ring through said abutment and said resilient rings and said annular flange being operative to cushioningly arrest relative axial bodily movement of said nut portion, a keeper ring disposed within said intermediate member and around said stop ring for maintaining said half-ring segments in said groove, a retaining ring disposed on said intermediate member outboard of said keeper ring for retaining said keeper ring in said intermediate member, and anti-friction bearing means disposed between said intermediate member and said nut portion operative to dissipate relative rotation between the latter and said intermediate member.

Claim 8

In an actuator assembly including a screw portion and a nut portion operatively associated with said screw portion in a manner whereby relative rotation therebetween effects concurrent relative bodily shiftable movement therebetween axially of said screw portion, the combination comprising, means defining a cylindrical surface on said screw portion, means defining an annular groove in said cylindrical surface disposed in a plane perpendicular to the axis of said screw portion, said groove being semicircular in cross section and terminating at said cylindrical surface in a pair of axially spaced lips, the continuous curvature of said groove effectively suppressing the formation of stress concentrations in the area of said groove when said screw portion is subjected to tensile forces applied at said groove, means defining an annular stop ring having a circular cross section of diameter substantially equal to the width of said groove, said stop ring being seated in said groove and defining an annular raised portion projecting radially outward of said cylindrical surface and a shear section disposed between the lips of said groove, means dividing said stop ring into a pair of identical semicircular half-ring segments for facilitating installation and removal of said stop ring from said screw portion, an elongated cylindrical intermediate member disposed around said cylindrical surface and radially spaced therefrom, means defining an inturned annular flange on said intermediate member closely slidably received on said cylindrical surface and engageable on said nut portion, said flange and said intermediate member defining an annular chamber closed at one end and extending over said stop ring, an annular abutment ring closely slidably received on said cylindrical surface in said annular chamber inboard of said stop ring, said abutment ring being engageable on said stop ring generally at said shear section of the latter, a plurality of annular elastically deformable compression rings disposed in said chamber between said abutment ring and said annular flange, said stop ring through said abutment and said resilient rings and said annular flange being operative to cushioningly arrest relative axial bodily movement of said nut portion, a keeper ring disposed within said intermediate member and around said stop ring for maintaining said half-ring segments in said groove, a retaining ring disposed on said intermediate member outboard of said keeper ring for retaining said keeper ring in said intermediate member, and anti-friction bearing means disposed between said intermediate member and said nut portion operative to dissipate relative rotation between the latter and said intermediate member.