Large-capacity spindle assemblies and collets for use in davenport multi-spindle screw machines
AssigneeBrinkman Products, Inc.
InventorsSandro G. Belpanno, James P. Hugick, Paul P. Francia
Life of this patent
Estimating the term…
Abstract
An improved spindle assembly for a Davenport® multi-axis screw machine is adapted to adequately hold one-inch round bar-stock in a collet against movement relative thereto attributable to machining operations performed on a cantilevered length of bar-stock held in and extending beyond the collet. The spindle assembly may permit the use of the screw machine on materials thought heretofore to be too difficult to machine on a screw machine. Cam surfaces on the inner spindle and collet may be coated with a low-friction material. A stress-relieving connection between the inner spindle and collet is provided.
Claims39
A spindle assembly for a Davenport® multi-axis screw machine having a head rotatably mounted on a frame and being adapted to be angularly indexed through a plurality of successive angular positions and having a plurality of circularly-spaced spindle assemblies mounted on said head, said screw machine being adapted to perform a plurality of machining operations on cantilevered lengths of bar-stock held by said spindle assembles, each spindle assembly comprising:
- a rotatable outer spindle having an inwardly-facing cam surface;
- an inner spindle coaxially arranged within said outer spindle for rotation with said outer spindle, and mounted for selective axial movement relative to said outer spindle;
- a collet mounted on said inner spindle for movement therewith, said collet having an outwardly-facing cam surface engaging said outer spindle cam surface and having a plurality of circularly-spaced fingers adapted to be moved radially inwardly when said inner spindle is moved in one axial direction relative to said outer spindle;
- spindle-moving means for selectively moving said inner spindle in said one axial direction relative to said outer spindle;
- a feed tube arranged within said inner spindle for axial movement relative to said inner spindle, said feed tube having a plurality of feed fingers that are adapted to engage a length of bar-stock within said feed tube;
- feed-tube-moving means for selectively moving said feed tube and feed fingers in either axial direction relative to said inner spindle;
- wherein the movement of said feed tube is adapted to be coordinated with the relative movement of said collet fingers such that said feed fingers may advance said bar-stock forwardly toward said collet when said collet is open;
- and
- wherein said spindle assembly is operatively adapted to adequately hold one-inch round bar-stock in said collet against axial and rotational movement relative thereto attributable to machining operations performed on a cantilevered length of said bar-stock held by and extending beyond said collet.
A spindle assembly for a Davenport® multi-axis screw machine having a head rotatably mounted on a frame and being adapted to be angularly indexed through a plurality of successive angular positions and having a plurality of circularly-spaced spindle assemblies mounted on said head, said screw machine being adapted to perform a plurality of machining operations on cantilevered lengths of bar-stock held by said spindle assembles, each spindle assembly comprising:
- a rotatable outer spindle having an inwardly-facing cam surface;
- an inner spindle coaxially arranged within said outer spindle for rotation with said outer spindle, and mounted for selective axial movement relative to said outer spindle;
- a collet mounted on said inner spindle for movement therewith, said collet having an outwardly-facing cam surface engaging said outer spindle cam surface and having a plurality of circularly-spaced fingers adapted to be moved radially inwardly when said inner spindle is moved in one axial direction relative to said outer spindle;
- spindle-moving means for selectively moving said inner spindle in said one axial direction relative to said outer spindle;
- a feed tube arranged within said inner spindle for axial movement relative to said inner spindle, said feed tube having a plurality of feed fingers that are adapted to engage a length of bar-stock within said feed tube;
- feed-tube-moving means for selectively moving said feed tube and feed fingers in either axial direction relative to said inner spindle;
- wherein the movement of said feed tube is adapted to be coordinated with the relative movement of said collet fingers such that said feed fingers may advance said bar-stock forwardly toward said collet when said collet is open;
- and
- wherein said spindle assembly is operatively adapted to adequately hold bar-stock formed of some materials heretofore considered too difficult to machine in a screw machine.
In a Davenport® multi-axis screw machine having a head rotatably mounted on a frame and being adapted to be angularly indexed between a plurality of successive angular positions and having a plurality of circularly-spaced spindle assemblies mounted on said head, said screw machine being adapted to perform a plurality of machining operations on cantilevered lengths of bar-stock held by said spindle assembles, said screw machine having a rotatable outer spindle having an inwardly-facing cam surface, having an inner spindle arranged within said outer spindle for rotation with said outer spindle and mounted for selective coaxial movement relative to said outer spindle, having a collet mounted on said inner spindle for movement therewith, said collet having an outwardly-facing cam surface engaging said outer spindle cam surface and having a plurality of circularly-spaced fingers adapted to be moved radially inwardly when said cam surfaces engage one another and said inner spindle is moved in one axial direction relative to said outer spindle, and having spindle-moving means for selectively moving said inner spindle in said one axial direction relative to said outer spindle;
- the improvement which comprises:
- the collet seat angle between said inner and outer spindle cam surfaces being greater than 7° and less than or equal to 25° so as to adequately hold bar-stock in said collet against axial and rotational movement relative thereto attributable to machining operations performed on a cantilevered portion of said bar-stock extending beyond said collet.
A Davenport® multi-axis screw machine having a collet adapted to be selectively mounted on a spindle;
- said spindle having:
- a forwardly-facing end face,
- a cylindrical outer surface extending rearwardly from the outer margin of spindle end face,
- an internally-threaded portion extending rearwardly from the inner margin of said spindle end face,
- an inner cylindrical surface axially spaced from said spindle threaded portion,
- a radially-thickened portion of said spindle being defined between said spindle inner and outer cylindrical surfaces;
- said collet having:
- a rearwardly-facing end face,
- an externally-threaded portion extending forwardly from the outer margin of said collet end face,
- a rearwardly-facing shoulder surface,
- an outer cylindrical surface extending forwardly from said shoulder surface, and
- an inner cylindrical surface extending forwardly from the inner margin of said collet end face;
- wherein the improvement comprises:
- said spindle having a frusto-conical surface extending forwardly and outwardly from said spindle inner cylindrical surface.
Dependencies are inferred from the claim text.