Quick tool change mechanism for machine tools

Claim 2

In a machine tool including a spindle having a tapered recess for seating a tool holder, the improvement of a quick tool change mechanism which comprises a drawbar, holder-to-drawbar connection means for releasably connecting said drawbar to said holder responsive to longitudinal movement of said drawbar relative to said spindle, and drawbar-movement-control means for moving said drawbar relative to said spindle including bias means operatively arranged between said drawbar and spindle and urging said drawbar to move relative to said spindle in one direction to pull said holder into seated engagement in said recess and release means for moving said drawbar relative to said spindle in the opposite direction to operate said holder-to-drawing connection means to disconnect said holder from said drawbar, said release means including means for holding said spindle against longitudinal movement while moving said drawbar in said opposite direction against the urging of said bias means and being operative to cause said holding means first to engage said spindle to prevent longitudinal movement thereof and thereafter to move said drawbar relative to said spindle in said opposite direction against the urging of said bias means, said holding means including means providing an external lock recess in said spindle and a slide movable into said lock recess and having an advance cam surface, and said release means further including a piston having a cam engageable with said advance cam surface to effect such locking movement of said slide.

Claim 3

The combination according to claim 1 wherein retract spring means urge said slide away from said spindle.

Claim 4

The combination according to claim 2 wherein said slide has an opening formed with opposite walls, said advance cam surface is on one of said walls, a retract cam surface is on the other of said walls, said cam comprises a roller movable into and out of said opening between and engageable with either of said cam surfaces, said roller when moved into said opening engaging said advance cam surface and when moved out of said opening engageable with said retract cam surface in case said retract spring means failed to retract said slide.

Claim 5

The combination according to claim 3 wherein movement of said piston into said opening so as to engage said cam with said advance cam surface is operative to move said slide into said lock recess and locking engagement with said spindle, after which said piston continues to move in the same direction to engage said drawbar to move the same relative to said spindle.

Claim 6

The combination according to claim 4 wherein said slide is arranged on one side of said spindle and is movable radially with respect thereto, and said holding means further comprises a second slide structurally similar to the aforementioned slide and arranged diametrically opposite thereof on the other side of said spindle, and said piston has a second cam cooperable with said second slide in a manner the same as described for the first mentioned slide.

Claim 7

The combination according to claim 5 wherein said release means further comprises means for guiding movement of said piston.

Claim 8

The combination according to claim 6 wherein said release means further comprises return spring means for said piston.

Claim 9

The combination according to claim 7 wherein said release means further comprises a diaphragm connected centrally to said piston and having a marginal portion and an intermediate unrestricted flexible portion, actuator chamber means securing said marginal portion to provide an actuator chamber and means for introducing pressurized fluid into said chamber for moving said piston against the urging of said return spring means.

Claim 10

The combination According to claim 8 wherein said release means further comprises means for selectively controlling the introduction of said pressurized fluid into said chamber.

Claim 11

In a machine tool including a tubular spindle having an internally tapered recess for seating the externally tapered spindle-insertable end portion of a tool holder, the improvement of a quick tool change mechanism which comprises a drawbar arranged in said spindle, the end face of said insertable end portion having a hook recess the mouth of which is formed by an inturned annular lip to provide a tool hook,, holder-to-drawbar connection means for releasably connecting said drawbar to said holder responsive to longitudinal movement of said drawbar relative to said spindle and including a slide member and a plurality of circumferentially spaced fingers projecting axially from said slide member, the free end of each of said fingers being radially movable and formed to provide an external hook, all such external hooks collectively providing a spindle hook which is radially expandable and retractable, and cam means for moving said fingers radially in and out, said spindle hook when contracted being insertable through said mouth into said hook recess past said lip by axial movement of said slide member in a direction toward said end portion and when in such relative axial position being expandable into locked engagement with said lip, and drawbar-movement-control means for moving said drawbar relative to said spindle including bias means operatively arranged between said drawbar and spindle and urging said drawbar to move relative to said spindle in one direction to pull said holder into seated engagement in said recess and release means for moving said drawbar relative to said spindle in the opposite direction to operate said holder-to-drawbar connection means to disconnect said holder from said drawbar.

Claim 12

In a machine tool including a tubular spindle having an internally tapered recess for seating the externally tapered spindle-insertable end portion of a tool holder, the improvement of a quick tool change mechanism which comprises a drawbar arranged in said spindle, the end face of said insertable end portion having a hook recess the mouth of which is formed by an inturned annular lip to provide a tool hook,, holder-to-drawbar connection means for releasably connecting said drawbar to said holder responsive to longitudinal movement of said drawbar relative to said spindle and including a slide member and a plurality of circumferentially spaced fingers projecting axially from said slide member, the free end of each of said fingers being radially movable and formed to provide an external hook, all such external hooks collectively providing a spindle hook which is radially expandable and retractable, and cam means for moving said fingers radially in and out, said spindle hook when contracted being insertable through said mouth into said hook recess past said lip by axial movement of said slide member in a direction toward said end portion and when in such relative axial position being expandable into locked engagement with said lip, and drawbar-movement-control means for moving said drawbar relative to said spindle including bias means operatively arranged between said drawbar and spindle and urging said drawbar to move relative to said spindle in one direction to pull said holder into seated engagement in said recess and release means for moving said drawbar relative to said spindle in the opposite direction to operate said holder-to-drawbar connection means to disconnect said holder from said drawbar.

Claim 13

The combination according to claim 10 wherein the free ends of said fingers are radially contractile, and said cam means include cam surfaces severally on the radially inner sides of said fingers at said free ends thereof and a cam mounted on said spindle within the cluster of said fingers and engageable with said cam surfaces.

Claim 14

The combination according to claim 11 wherein said cam means further include a sleeve mounted on said spindle and radial struts severally extending in the spaces between adjacent pairs of fingers, said struts at their outer radial ends being connected to said sleeve and at their inner radial ends being connected to said cam.

Claim 15

The combination according to claim 12 wherein said struts are fewer in number than said spaces.

Claim 16

The combination according to claim 10, further comprising tool ejection means responsive to said axial movement of said slide member in said direction for ejecting said inserted holder upon disengagement of said spindle and tool hooks.

Claim 17

The combination according to claim 12, further comprising a tool ejector member slidably mounted on said sleeve and having slots receiving said struts and pushed against said end portion by said slide member when axially moved in said direction.

Claim 18

The combination according to claim 12, further comprising a guide spider on said cam adjacent said fingers and including a plurality of radial fins arranged in said spaces having guide surfaces exposed radially outwardly of said external hooks when said spindle hook is radially contracted.

Claim 19

The combination according to claim 13, further comprising a guide spider on said cam adjacent said fingers and including a plurality of radial fins arranged in said spaces having guide surfaces exposed radially outwardly of said external hooks when said spindle hook is radially contracted, said fins being the same in number as said struts and arranged in the same ones of said spaces.