Precision quill-feed unit

• US 5,888,033 A
• Filed: 10/09/1997
• Issued: 03/30/1999
• Est. Priority Date: 10/09/1997
• Status: Expired due to Fees

• Current Assignee: Zagar Inc.
• Original Assignee: Zagar Inc.
• Inventors: Jewell, Robert W., Zagar, John F., Lingafelter, Thomas, Zagar, Frank G.
• Primary Examiner(s): Howell, Daniel W.
• Application Number:
  US08/947,701
• Time in Patent Office: 537 Days
• Field of Search: 408/14, 408/17, 408/124, 408/130, 408/141, 408/241 S
• US Class Current: 408/14
• CPC Class Codes: B23Q 1/70 Stationary or movable members for carrying working-spindles for attachment of tools or work B23Q1/01 takes precedence; designed to be moved by using particular mechanisms B23Q1/44
• CPC Class Codes: B23Q 5/32 Feeding working-spindles feeding working-spindle supports B23Q5/34
• CPC Class Codes: Y10T 408/18 with stopping upon completion of prescribed operation
• CPC Class Codes: Y10T 408/65 Means to drive tool

Abstract

A self-contained precision quill-feed unit is provided with a positive stop arrangement to control depth of tool feed. The stop position is adjustable from the exterior of the unit and the stop abutments associated with moving and stationary members are positioned in such manner that no yawing forces are imposed on the quill, drive shaft and spindle of the unit. Additionally, yawing forces generated by the mechanical resistance of a known type of hydraulic constant velocity control (CVC) cylinder are opposed by reaction forces associated with the anti-rotation linkage that prevents rotation of the quill. Together these features provide overall a machine in which quill, drive shaft and spindle deflection or yawing is minimized or prevented.

Claims

1. In a quill-feed unit for feeding a drill or other end-cutting tool, a housing body, a rotatable drive shaft splined at its power output end, a non-rotating quill slidably received within the housing body for axial movement in advancing and retracting directions, said quill coaxially surrounding said rotatable drive shaft, a spindle coaxial with said quill and drive shaft and coupled for advancing and retracting movement with said quill and for rotation with said drive shaft, and adjustable stop means for determining the limit of said axial movement of said quill in said advancing direction, said stop means comprising a moving abutment associated with and moving with said axially moving quill and a fixed abutment engageable by said moving abutment, the improvement comprising a hubbed worm gear mounted in the housing body coaxially with said quill for relative longitudinal and rotational movement with respect thereto, said worm gear being meshed with a worm drive mounted on said housing body and turnable from the exterior of said housing body, a nut threadedly engaged on the hub of said worm gear, and means restraining said nut against rotation while allowing axial movement thereof relative to said housing body, said fixed abutment having portions at opposite sides of the axis of said quill and comprising an end face of said nut, said moving abutment presenting a moving abutment face moving with said quill and having portions on opposite sides of the axis of said quill, said fixed and moving abutments engaging at points of engagement that are balanced on opposite sides of the axis of said quill.

2. A device as in claim 1, said fixed and moving abutments engaging at an area of engagement that surrounds the quill.

3. A device as in claim 1, said worm gear being free of contact with said quill and having cylindrical shoulders at its outside diameter, said shoulders piloting said worm gear in its turning motion in the housing body, said threaded engagement between said nut and the hub of said worm gear acting as a piloting guide.

4. A device as in claim 1, said means restraining said nut against rotation comprising a set screw carried by said housing body and a cooperating groove formed in said nut.

5. In a quill-feed unit for feeding a drill or other end-cutting tool, a housing body, a rotatable drive shaft splined at its power output end, a non-rotatable quill slidably received within the housing body for axial movement in advancing and retracting directions, said quill coaxially surrounding said rotatable drive shaft, stop means for determining the limit of said axial movement of said quill in said advancing direction, anti-rotation guide means for accommodating axial movement of said quill while preventing it from rotation, said guide means including a guide element mounted at a first end of a transversely extending bracket which is centrally fixed to said axially moving quill for movement therewith, a rod-and-cylinder linkage mounted on said bracket at the other or second end thereof and on the other side of said quill from said guide element, said rod-and-cylinder linkage being mounted axially parallel to said quill and moving with said axially moving quill, hydraulic flow limiting means associated with the cylinder of said rod-and-cylinder linkage, said rod-and-cylinder linkage being adapted to restrain the rate of movement of the quill toward the end of its advance by contact of the end of the rod of said rod-and-cylinder linkage with a fixed member whereby said rod is forced by the continuing advance of said quill to retract into the cylinder of said rod-and-cylinder linkage but only at a rate allowed by said hydraulic flow limiting means, the improvement which comprises a combined anti-rotation and anti-yaw bushing-and-shaft guide associated with said first end of said bracket, said guide including an open-sided bushing-type bearing on said first end of said bracket and a fixed shaft along which said bearing slides to both restrain said bracket and quill from rotation and generate reaction forces to yawing stresses imposed on the bracket and quill by engagement of said rod with said fixed member, whereby said reaction forces relieve yawing stress loads which would otherwise be imposed on the quill, thereby reducing or eliminating quill and spindle deflection or yawing related to the axial compressive force imposed on said rod as it engages said fixed member and is then forced under hydraulic resistance to retract into the CVC cylinder.

6. In a quill-feed unit for feeding a drill or other end-cutting tool, a housing body, a rotatable drive shaft splined at its power output end, a non-rotatable quill slidably received within the housing body for axial movement in advancing and retracting directions, said quill coaxially surrounding said drive shaft, a spindle coaxial with said drive shaft and quill, said spindle being splined to and driven rotatably by said drive shaft, said spindle being rotatable with respect to said quill and being driven axially in said advancing and retracting directions by said quill, a stop for determining the limit of said axial movement of said quill and spindle in said advancing direction, said stop comprising a moving abutment associated with and moving with said axially moving quill and an axially adjustable fixed abutment carried by said housing body and engageable by said moving abutment at points of engagement that are balanced on opposite sides of the axis of said quill to thereby determine said limit of said advancing axial movement of said quill and spindle without imposing pitching or yawing loads on said quill, a transversely extending bracket fixed to said axially moving quill for movement therewith, a rod-and-cylinder linkage mounted at one end of the bracket, said rod-and-cylinder linkage being mounted axially parallel to said quill and moving with said axially moving quill, hydraulic flow limiting means associated with the cylinder of said rod-and-cylinder linkage, said rod-and-cylinder linkage being adapted to restrain the rate of movement of the quill toward the end of its advance by engagement of the end of the rod of said rod-and-cylinder linkage with a fixed rod-stop or whereby said rod is forced by the continuing advance of said quill to retract into the cylinder of said rod-and-cylinder linkage but only at a rate allowed by said hydraulic flow limiting means, said engagement with the fixed rod-stop imposing yawing stresses on the quill via the bracket, an open-sided bushing-type bearing at the other end of said bracket and on the other side of the quill from said rod-and-cylinder linkage, a fixed shaft supported by said housing body and slidingly received in said bushing-type bearing, said bushing-type bearing engaging said fixed shaft along a portion of the length of said fixed shaft whereby said engagement not only prevents rotation of said quill with respect to said housing body while accommodating axial movement of said quill, but also resists said yawing stresses imposed on said quill by said axial loading imposed at the other end of said bracket.

7. A device as in claim 6, said fixed and moving abutments engaging at an area of engagement that surrounds the quill.

8. A device as in claim 6, a hubbed worm gear mounted in the housing body coaxially with said quill for relative longitudinal and rotational movement with respect thereto, said worm gear being meshed with a worm drive mounted on said housing body and turnable from the exterior of said housing body, a nut threadedly engaged on the hub of said worm gear, and means restraining said nut against rotation while allowing axial movement thereof relative to said housing body, said fixed abutment having portions at opposite sides of the axis of said quill and comprising an end face of said nut.

9. A device as in claim 8, said moving abutment comprising an abutment face associated with and moving with said transversely extending bracket.

10. A device as in claim 8, said means restraining said nut against rotation comprising a set screw carried by said housing body and a cooperating groove formed in said nut.

11. A device as in claim 8, said worm gear being free of contact with said quill and having cylindrical shoulders at its outside diameter, said shoulders piloting said worm gear in its turning motion in the housing body, said threaded engagement between said nut and the hub of said worm gear acting as a piloting guide.