Quick changeable collet clamping assembly

A clamping assembly for releasably clamping a collet, the clamping assembly comprising:

• a collet adapter comprising a first interior surface defining a first bore concentric about a longitudinal axis, the first bore extending from a collet loading end to a draw bar receiving end of the collet adapter, the collet adapter having a mounting portion configured to secure the collet adapter to a spindle of a machine;
• an expansion sleeve removably disposed in the first bore and in sliding engagement with a portion of the first interior surface, the expansion sleeve having a second interior surface defining a second bore extending between a first axially facing sleeve end and a second axially facing sleeve end thereof, the second interior surface having a cylindrical guiding diameter portion proximate the second axially facing sleeve end, the expansion sleeve having a first exterior surface extending therearound and the expansion sleeve having a portion of the first exterior surface defining a clamping portion proximate the first axially facing sleeve end thereof, the expansion sleeve extending coaxially with a longitudinal axis thereof and between the first axially facing sleeve end and the second axially facing sleeve end;
• and
• a draw pin extending coaxially with the longitudinal axis and between a first draw pin end and a second draw pin end, the draw pin having an axially facing pin-stop surface facing away from the second draw pin end, the draw pin extending partially in the second bore and in axially moveable relation to the expansion sleeve with the first draw pin end extending outwardly from the first axially facing sleeve end of the expansion sleeve and the second draw pin end and the pin-stop surface extending outwardly from the second axially facing sleeve end of the expansion sleeve, the draw pin having a second exterior surface, a first portion of the second exterior surface proximate the second draw pin end being a cylindrical shoulder and a second portion of the second exterior surface proximate the first draw pin end being a cylindrical guiding surface, the cylindrical guiding surface centering the expansion sleeve thereon along the cylindrical guiding diameter of the second interior surface of the expansion sleeve and maintaining concentricity between the draw pin and the expansion sleeve;
• the expansion sleeve being axially displaceable between a clamped position and an unclamped position in response to axial movement of the draw pin in the expansion sleeve, wherein in the clamped position the pin-stop surface axially engages the second sleeve end of the expansion sleeve;
• wherein in a clamped position, the cylindrical shoulder of the draw pin engages a cylindrical portion of the second interior surface of the expansion sleeve, thereby preventing the expansion sleeve from collapsing radially inwardly and to retain the clamping portion radially outward to secure the collet in the collet adapter.

An expansion sleeve for a clamping assembly, the expansion sleeve comprising:

• an interior surface defining a bore extending between a first axially facing sleeve end and a second axially facing sleeve end thereof, the expansion sleeve having an exterior surface extending therearound and a portion of the first exterior surface defining a tapered clamping portion proximate the first end thereof;
• the clamping portion comprising at least a first axial leg and a second axial leg, the first axial leg and the second axial leg being separated circumferentially by a first axial slot and a second axial slot, each extending axially inward from the first axially facing sleeve end and radially through the expansion sleeve from the exterior surface to the interior surface, wherein the first axial slot and the second axial slot impart flexibility to the clamping portion so that the first axial leg and the second axial leg flex radially inward;
• the expansion sleeve further comprising at least a third axial leg and a fourth axial leg, the third axial leg and the fourth axial leg being separated circumferentially by a third axial slot and a fourth axial slot, each extending axially inward from the second axially facing sleeve end and radially through the expansion sleeve from the exterior surface to the interior surface, wherein the third axial slot and the fourth axial slot impart flexibility to the expansion sleeve so that the third axial leg and the fourth axial leg flex radially inward;
• and
• wherein the first axial leg joins integrally with the third axial leg and the fourth axial leg at a position located between the first axially facing sleeve end and a midpoint of the expansion sleeve and the third axial leg joins integrally with the first axial leg and the second axial leg at a position located between the second axially facing sleeve end and the midpoint of the expansion sleeve, thereby forming a tubular configuration of the expansion sleeve.

A clamping assembly for releasably clamping a collet, the clamping assembly comprising:

• a collet adapter having a mounting portion configured to secure the collet adapter to a spindle of a machine;
• an expansion sleeve movably disposed in collet adapter, the expansion sleeve extending coaxially with a longitudinal axis thereof and between a first axially facing sleeve end and a second axially facing sleeve end;
• a draw pin extending coaxially with the longitudinal axis and between a first draw pin end and a second draw pin end, the draw pin having an axially facing pin-stop surface facing away from the second draw pin end, the draw pin extending partially in and in axially moveable relation to the expansion sleeve with the first draw pin end extending outwardly from the first axially facing sleeve end of the expansion sleeve and the second draw pin end and the pin-stop surface extending outwardly from the second axially facing sleeve end of the expansion sleeve;
• the first axially facing sleeve end facing towards the pin-stop surface and the second axially facing sleeve end facing away from the pin-stop surface, the entire expansion sleeve being axially displaceable in only one first axial direction when moving from a clamped position to an unclamped position and the entire expansion sleeve being axially displaceable in only one second axial direction opposite to the first direction when moving from an unclamped position to a clamped position in response to axial movement of the draw pin in the expansion sleeve.