US 4,028,763 AGranted

Tap holder

OwnerAl Jennerinventor

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Abstract

A tap holder which is particularly adapted for use on a numerical-controlled machine is the subject matter herein. The tap holder includes an elongated shaft, which has a conventional tap collet on one end thereof. A tap holder body is rotatably and axially movably mounted on the shaft. The body is particularly adapted for connection to a tool holder of a numerically-controlled machine. A collar is mounted on the shaft. A pair of balanced springs is mounted on the shaft on opposed sides of the collar. Both springs are connected to the body to allow relative axial movement between the shaft and the body. A limited drive torque assembly drivingly connects the shaft to the body to drive the shaft at a torque which does not exceed a predetermined maximum amount.

Claims1

Dependent claims

A tap holder particularly adapted for use on a numerical-controlled machine comprising, an elongated tap holder shaft, a tap holder collet on one end of said shaft for releasably holding a tap, the elongated tap holder shaft has an integral non-circular cross-section drive tail on the end of the shaft opposite to the end having the tap holder collet;

a tap holder body rotatably mounted on the tap holder shaft and being adapted for releasable driving connection to a tool holder of a numerical-controlled machine, said tap holder body including a pair of opposed slots at one end of an internal thread at said end, a drive rate compensating assembly connecting the tap holder body and the tap holder shaft and allowing relative axial movement therebetween, said drive rate compensating assembly including a spring collar releasably mounted on said shaft, a set screw holding the spring collar on said shaft, a first coil spring having one end connected to the spring collar and the other end connected to the tap holder body, and a second coil spring having one end connected to the spring collar and the other end connected to the tap holder body, said first and second coil springs having substantially equal spring rates, whereby the springs allow axial displacement of the shaft relative to the body;
and said tap holder body has a screw aperture contained therein, alignable with the set screw to provide a means of access for manipulating the set screw, and a limited drive torque assembly drivingly connecting the tap holder shaft to the tap holder body for turning the tap holder shaft at a torque under a selected maximum amount, said limited drive torque assembly includes a substantially flat body drive plate having a pair of ears extending into the slots of the body for driving rotation with the body, a substantially flat shaft drive plate having an aperture mateably receiving the drive tail of the tap holder shaft and being axially movable along the drive tail, a substantially flat brass washer positioned between the shaft drive plate and the body drive plate and frictionally engaging said shaft drive plate and the body drive plate to provide a frictional driving connection between the shaft drive plate and the body drive plate, a second brass washer frictionally engaging the body drive plate, a steel washer frictionally engaging the second brass washer, and an end cap threadedly mounted in the tube and engaging the steel washer to determine the normal force between the first brass washer and the body drive plate and the shaft drive plate to determine the maximum torque transmitted between the tap holder body and the tap holder shaft;
and said drive rate compensating assembly including a spring collar releasably mounted on the tap holder shaft, a first coil spring having one end engaging the spring collar and the other end engaging the body, and a second coil spring opposed to the first spring, said second coil spring having one end engaging the spring collar and the other end engaging the body drive plate, said springs having equal spring rates, whereby the springs allow axial displacement of the tap holder shaft relative to the tap holder body.

Dependencies are inferred from the claim text.

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Abstract

a tap holder body rotatably mounted on the tap holder shaft and being adapted for releasable driving connection to a tool holder of a numerical-controlled machine, said tap holder body including a pair of opposed slots at one end of an internal thread at said end, a drive rate compensating assembly connecting the tap holder body and the tap holder shaft and allowing relative axial movement therebetween, said drive rate compensating assembly including a spring collar releasably mounted on said shaft, a set screw holding the spring collar on said shaft, a first coil spring having one end connected to the spring collar and the other end connected to the tap holder body, and a second coil spring having one end connected to the spring collar and the other end connected to the tap holder body, said first and second coil springs having substantially equal spring rates, whereby the springs allow axial displacement of the shaft relative to the body;
and said tap holder body has a screw aperture contained therein, alignable with the set screw to provide a means of access for manipulating the set screw, and a limited drive torque assembly drivingly connecting the tap holder shaft to the tap holder body for turning the tap holder shaft at a torque under a selected maximum amount, said limited drive torque assembly includes a substantially flat body drive plate having a pair of ears extending into the slots of the body for driving rotation with the body, a substantially flat shaft drive plate having an aperture mateably receiving the drive tail of the tap holder shaft and being axially movable along the drive tail, a substantially flat brass washer positioned between the shaft drive plate and the body drive plate and frictionally engaging said shaft drive plate and the body drive plate to provide a frictional driving connection between the shaft drive plate and the body drive plate, a second brass washer frictionally engaging the body drive plate, a steel washer frictionally engaging the second brass washer, and an end cap threadedly mounted in the tube and engaging the steel washer to determine the normal force between the first brass washer and the body drive plate and the shaft drive plate to determine the maximum torque transmitted between the tap holder body and the tap holder shaft;
and said drive rate compensating assembly including a spring collar releasably mounted on the tap holder shaft, a first coil spring having one end engaging the spring collar and the other end engaging the body, and a second coil spring opposed to the first spring, said second coil spring having one end engaging the spring collar and the other end engaging the body drive plate, said springs having equal spring rates, whereby the springs allow axial displacement of the tap holder shaft relative to the tap holder body.