Clutch for drilling machine

A drilling machine for tapping a high pressure pipeline, comprising:

• a boring bar;
• means for attaching a tool to said boring bar;
• a body tube, said boring bar being positioned in said body tube;
• a feed tube, said body tube being positioned in said feed tube;
• means for coupling said feed tube and said body tube allowing rotation of said feed tube relative to said body tube and axial advancement relative to said body tube;
• and
• means for coupling said boring bar and said feed tube for rotating said feed tube at a different rate than said boring bar, said coupling means including a clutch disc rigidly secured to said boring bar, a clutch member secured to said feed tube, a feed adjustment nut threadably attached to said feed tube, and a friction disc between said clutch disc and said clutch member, said clutch disc and said clutch member including high friction surfaces engaging said friction disc.

The combination comprising:

• a boring bar;
• means for attaching a tool for tapping a high pressure pipeline to said boring bar;
• a body tube, said boring bar extending through and being rotatable relative to said body tube;
• an internally threaded feed tube, said body tube being threadably mounted in said feed tube;
• a clutch mechanically coupling said boring bar and said feed tube, said clutch including a clutch disc secured to said boring bar, a feed adjustment nut threadably mounted on said feed tube, a clutch member secured to said feed tube between said feed adjustment nut and said clutch disc, a friction disc of organic metal impregnated material between said clutch disc and said clutch member, said clutch disc including a surface engaging said friction disc, said clutch disc surface including serrations, said clutch member including a surface engaging said friction disc, said clutch member surface including serrations and means for biasing said clutch member into said friction disc.