초록 ▼

Precision movement of a table part by movement of a nut over a lead screw is achieved by a less rigorously precise structure than has heretofore been thought necessary. To that end the screw is fixedly supported only at one end and is rotatable in bearings mounted within a rigidly mounted tube which

Precision movement of a table part by movement of a nut over a lead screw is achieved by a less rigorously precise structure than has heretofore been thought necessary. To that end the screw is fixedly supported only at one end and is rotatable in bearings mounted within a rigidly mounted tube which at least partially surrounds the screw, play in those bearings is minimized by exerting axial pressure thereon, the nut is especially designed to engage the screw only at separated points, thereby to reduce friction and play in the nut, and the nut is connected to the moveable table part by structure passing through an opening in the tube and resiliently engaging the moveable table part to compensate for displacement and play.

대표청구항 ▼

The invention claimed is: 1. In a precision table comprising a base, a table moveable relative to said base, and means operatively connected to said table for moving same which comprises a lead screw, a nut on said screw moveable therealong as said screw is rotated, and a part operatively connected

The invention claimed is: 1. In a precision table comprising a base, a table moveable relative to said base, and means operatively connected to said table for moving same which comprises a lead screw, a nut on said screw moveable therealong as said screw is rotated, and a part operatively connected between said nut and said table, the improvement which comprises a support for one end of said screw, said support comprising a bearing in which said one end of said screw is operatively rotatably received and from which said screw extends, a tube mounted on and extending from said support and surrounding said screw, said tube having an opening through which said part extends from said nut to said table and along which said part can move as said nut moves along said screw, and a second bearing in said tube remote from said first bearing in which the other end of said screw is operatively rotatably received, in which said part is secured to said nut and extends toward said table, in combination with a member operatively connected to said table against which said part is adapted to abut, said member comprising a pair of spaced abutments between which said part is adapted to be received, and resilient means active on said part to urge it against said member, further comprising means in said tube beyond said second bearing for exerting pressure on said second bearing toward said first bearing, thereby to reduce play in one or both of said bearings. 2. The precision table of claim 1, in which said abutments are generally raised from the surface of said member, and said part is adapted to simultaneously engage said abutments. 3. The precision table of claim 2, in which said resilient means is active between said part and said member to move said part into engagement with said member. 4. The precision table of claim 2, in which said resilient means comprises spring means active between said part and said member to move said part into engagement with said member. 5. The precision table of claim 1 in which said abutments are generally raised from the surface of said member and are generally part spherical as they extend from said surface, and said part is adapted to simultaneously engage said abutments. 6. The precision table of claim 5, in which said abutments are ball-shaped. 7. The precision table of claim 5, in which said abutments comprise balls mounted on and extending from said member. 8. In the precision table of claim 1, means in said tube beyond said second bearing for exerting pressure on said second bearing toward said first bearing, thereby to reduce play in one or both of said bearings. 9. The precision table of claim 8, in which the pressure exerted by said means is adjustable. 10. The precision table of claim 9, in which said adjustable means comprises an adjustment screw accessible adjacent to the end of said tube, threadedly mounted in said tube and operatively connected to said second bearing. 11. The precision table of claim 1, in which the pressure exerted by said means is adjustable. 12. The precision table of claim 11, in which said adjustable means comprises an adjustment screw accessible adjacent to the end of said tube, threadedly mounted in said tube and operatively connected to said second bearing. 13. The precision table of claim 1, in which said abutments are generally raised from the surface of said member and are generally part spherical as they extend from said surface and said part is adapted to simultaneously engage said abutments. 14. The precision table of claim 13, in which said abutments are ball-shaped. 15. The precision table of claim 13, in which said resilient means comprises spring means active between said part and said member to move said part into engagement with said member. 16. In a precision table comprising a base, a table moveably related to said base, and means operatively connected to said table for moving same, the improvement which comprises a lead screw operatively connected to said base, a nut on said screw moveable therealong as said screw is rotated, a part secured to said nut and extending toward said table, and a member operatively connected to said table against which said part is adapted to abut, said member comprising a pair of spaced abutments between which said part is adapted to be received, and resilient means operatively active on said part to urge it against said member, in which said abutments are generally raised from the surface of said member and generally tapered in a direction away from said surface, and said part is adapted to simultaneously engage said abutments, in which said resilient means is active between said part and said member to move said part into engagement with said member, in which said resilient means comprises a generally "U" shaped element having arms connected by a head, said head engaging said part on the side of said part facing away from said member, said arms passing relatively freely through said member, and a spring active on said arms to move said head toward said member. 17. The precision table of claim 16, in which said nut comprises a body with an internally threaded opening extending in an axial direction therethrough, said body having a transversal slot partly therethrough and extending from the outer surface of said body into said through opening, thus dividing one portion of said body into two axially separated parts, and a screw in one of said parts located radially beyond said through opening, extending across said slot, and engaging the other of said parts so as to adjustably move said parts toward and away from one another. 18. The precision table of claim 16, in which said nut comprises a body with an internally threaded opening extending in an axial direction therethrough said body having a transversal slot partly therethrough and extending from the outer surface of said body into said through opening, thus dividing one portion of said body into two axially separated parts, and means for adjustably causing said parts to move toward and away from one another. 19. In a precision table comprising a base, a table moveable relative to said base, and means operatively connected to said table for moving same which comprises a lead screw, a nut on said screw moveable therealong as said screw is rotated, and a part operatively connected between said nut and said table, the improvement which comprises a support for one end of said screw, said support comprising a bearing in which said one end of said screw is operatively rotatably received and from which said screw extends, a tube mounted on and extending from said support and surrounding said screw, said tube having an opening through which said part extends from said nut to said table and along which said part can move as said nut moves along said screw, and a second bearing in said tube remote from said first bearing in which the other end of said screw is operatively rotatably received, in which said part is secured to said nut and extends toward said table, in combination with a member operatively connected to said table against which said part is adapted to abut, said member comprising a pair of spaced abutments between which said part is adapted to be received, and resilient means active on said part to urge it against said member, in which said resilient means comprises a generally "U" shaped element having arms connected by a head, said head engaging said part on the side of said part facing away from said member, said arms passing relatively freely through said member, and a spring active on said arms to move said head toward said member.