Rock bit cone lock and method

Rotary rock bit apparatus comprising:

• (a) a journal member having an axis;
• (b) a cutting element having an axis and coaxially circumscribing said journal member;
• (c) means for supporting said cutting element on said journal member for coaxial rotation relative thereto, said means for supporting said cutting element on said journal member including an annular array of ball bearings;
• and
• (d) means, responsive to a predetermined degree of skew occurring between said axes, for materially inhibiting rotation of said cutting element relative to said journal member, said means for materially inhibiting rotation including means for utilizing a plurality of said ball bearings to rotationally lock said cutting element on said journal member,
• said journal member having an annular race coaxially formed thereon and operatively receiving a radially inner portion of said annular array of ball bearings, and
• said means for materially inhibiting rotation further including a lockup groove formed on said journal member and communicating with said annular race.

A rotary rock bit comprising:

• (a) a cutting element having an opening therein, and an annular race formed in the surface of said opening;
• (b) a journal member received in said opening, said journal member having an annular race formed thereon;
• (c) an annular array of ball bearings operatively carried in said annular races and captively retaining said cutting element on said journal member;
• and
• (d) means, responsive to a predetermined degree of clearance between said races, for materially inhibiting rotation of said cutting element relative to said journal member by axially shifting at least one of said ball bearings out of said races.

A method of preventing wear-induced dislodgement of a cutting cone from a journal pin of a rock bit, said cutting cone being captively retained on said journal pin by an internal annular array of ball bearings, said method comprising the steps of:

• (a) permitting only a predetermined amount of rotationally-induced wear between preselected laterally facing surfaces disposed within said cutting cone, said predetermined amount of wear being below a wear amount sufficient to allow axial dislodgement of said cutting cone from said journal pin;
• (b) causing at least one ball bearing to shift axially of said journal pin, and out of said annular array, in response to the attainment of said predetermined amount of rotationally-induced wear;
• and
• (c) utilizing the shifted ball bearing to inhibit subsequent rotation of said cutting cone relative to said journal pin.

Rock bit apparatus comprising:

• (a) a body;
• (b) a support arm depending from said body;
• (c) a journal pin projecting outwardly from said support arm, said journal pin having a longitudinal axis, a cylindrical outer side surface, and an annular race coaxially formed in said laterally outwardly facing surface;
• (d) a cutting cone having an axis, a central axial opening defining in said cone a cylindrical interior side surface, and an annular race coaxially formed in said interior side surface, said journal pin being coaxially received in said central cutting cone opening with said interior cutting cone surface outwardly circumscribing said journal pin outer side surface and said annular races being axially aligned;
• (e) an annular array of ball bearings operatively carried within said races, said ball bearings captively retaining said cutting cone on said journal pin;
• and
• (f) groove means, communicating with said annular races, for axially receiving at least one of said ball bearings in response to a predetermined degree of skewing between said axes of said journal pin and said cutting cone during rotation of said cutting cone, and for utilizing the received ball bearing to cause a rotational inhibition between said cutting cone and said journal pin.

A rotary rock bit comprising:

• (a) a journal pin;
• (b) a cutting cone captively retained on said journal pin and rotatable relative thereto;
• (c) a plurality of locking members carried between said journal pin and said cutting cone;
• and
• (d) means, responsive to a predetermined degree of wear between said journal pin and said cutting cone, for causing one or more of said lockup members to shift relative to said journal pin and become wedged between said journal pin and said cutting cone to thereby materially inhibit rotation of said cutting cone relative to said journal pin,
• said plurality of lockup members comprising an annular array of ball bearings, and
• said means for causing one or more of said lockup members to shift including means for defining a depression on said journal pin, and means for causing one or more of said ball bearings to shift into said depression on said journal pin.

A rotary rock bit comprising:

• (a) a journal pin having a depression formed thereon;
• (b) a cutting cone captively retained on said journal pin and rotatably relative thereto;
• (c) a plurality of lockup members carried between said journal pin and said cutting cone in said depression;
• and
• (d) means, responsive to a predetermined degree of wear between said journal pin and said cutting cone, for causing one or more of said lockup members to shift relative to said journal pin and become wedged between said journal pin and said cutting cone to thereby materially inhibit rotation of said cutting cone relative to said journal pin, said means for causing one or more of said lockup members to shift including means for causing one or more of said lockup members to be displaced from said depression.