US 4,799,833 A · Clutch for positive feed drill

Abstract

The invention relates to a torque-limiting clutch for use in combination with a positive feed drill that has a reversible motor and reversible driving means. A preferred use of the clutch is in combination with a drill that has a reversible motor rapid advance system. The clutch provides direct drive in a forward mode and is torque-limiting in a reverse mode so as to protect the gears from breaking due to excessive torque while the gears are turning in reverse during the rapid advance mode. In the reverse mode, the torque-limiting clutch protects the drill bit as it bears on the workpiece and prevents unscrewing of the drilling and mounting components. In a preferred embodiment the clutch is mounted on a shaft and is comprised of two clutch jaws that drive through lugs mounted on the jaws. The lugs provide direct drive in a forward rotation, but are shaped so as to allow the jaws to disengage when the torque is excessive in a reverse rotation.

Claims19

Dependent claims

A reversible clutch for use in combination with a positive feed drill having a reversible motor, said clutch being torque-limiting in a reverse direction and comprising:

a clutch shaft;
a first clutch jaw affixed to said shaft;
a second clutch jaw slidably mounted on said shaft such that it rotates freely on the shaft;
means for securing the first clutch jaw in engagement with the second clutch jaw such that the first clutch jaw drives the second clutch jaw in a positive direct drive in a forward rotation;
and
said means permitting limited torque in a reverse rotation by allowing the second clutch jaw to disengage from the first clutch jaw when the clutch experiences excessive torque in a reverse rotation.

3 more elements

In a positive feed drill system, the combination comprising:

a drill housing;
a rotatable tool spindle mounted in the housing, said spindle being capable of reciprocal movement in advancing and withdrawing;
a reversible motor included in the housing;
reversible gear means in said housing for rotating and selectively advancing or withdrawing the spindle;
means for rapidly advancing the spindle with the motor and gear means in reverse;
transmission means in said housing and interposed between said motor and said gear means, said transmission means for transmitting the motor output to said gear means;
a reversible clutch interconnecting the gear means and the transmission means;
said clutch including a shaft, a first clutch jaw affixed to the shaft, and a second clutch jaw slidably mounted on the shaft such that it rotates freely on the shaft;
biasing means for biasing said second clutch jaw toward said first clutch jaw;
forward engaging means for engaging said first clutch jaw with said second clutch jaw in direct drive in a forward rotation;
and
reverse torque-limiting means for engaging said first clutch jaw with said second clutch jaw in a reverse rotation and for disengaging the first clutch jaw from the second clutch jaw when the clutch encounters excessive torque in a reverse rotation.

9 more elements

Dependencies are inferred from the claim text.

Clutch for positive feed drill

Life of this patent

Clutch for positive feed drill

Life of this patent

Abstract

Claims19