Bit holding system with an opening for removal of broken bits

A cutting tool assembly comprising:

• a bit holder comprising a forward portion, a rearward portion, a central opening positioned between the forward portion and the rearward portion, an upper reinforcing portion extending between the forward portion and the rearward portion, and a generally planar mounting surface between the forward and rearward portions positioned on an opposite side of the central opening from the upper reinforcing portion, the forward portion defining a front end and a front aperture having an axis inclined relative to the mounting surface, and the rearward portion having a beveled surface adjacent the mounting surface and defining a rear aperture extending from the beveled surface, the rear aperture having an inner dimension and being open to the front aperture;
• a cutting bit mounted in the front aperture and including a shank portion having an outer diameter and rearward end accessible through the rear aperture of the bit holder rearward portion and accessible through the central opening, the cutting bit extending beyond the front end, and wherein the inner dimension of the rear aperture is larger than the outer diameter of the cutting bit to allow the shank portion of a broken cutting bit to pass through the rear aperture for removal;
• a sleeve member having a body member constructed to be received in the front aperture through a forward end of the front aperture, the body member defining an outer surface, the sleeve member having an abutment surface adapted for engagement with a contact face of the forward portion to prevent axial movement of the sleeve member in a direction toward the rearward portion, the sleeve member further having a bore therein for coaxially rotatably receiving the shank portion of the cutting bit and an engagement surface adapted to be engaged by a shoulder on the bit;
• and
• means for retaining the sleeve member relative to the forward portion comprising an area of interference fit between an inner surface of the front aperture and the outer surface adapted to prevent rotation and axial movement of the sleeve member while in use without the application of independent means for urging the sleeve member toward the rearward portion of bit holder and to allow the removal of the sleeve member from the front aperture of the front portion by the manual application of force to the sleeve member.

A cutting tool assembly comprising:

• a bit holder comprising a forward portion, a rearward portion, a central opening positioned between the forward position and the rearward portion, an upper reinforcing portion extending between the forward portion and the rearward portion, and a generally planar mounting between the forward and rearward portions positioned on an opposite side of the central opening from the upper reinforcing portion, the forward portion defining a front end and a front aperture having an axis inclined relative to the mounting surface, and the rearward portion having a beveled surface adjacent the mounting surface and defining a rear aperture extending from the beveled surface, the rear aperture having an inner dimension and being open to the front aperture;
• a cutting bit mounted in the front aperture and including a shank portion having an outer diameter and a rearward end accessible through the rear aperture of the bit holder rearward portion and accessible through the central opening, the cutting bit extending beyond the front end, and wherein the inner dimension of the rear aperture is larger than the outer diameter of the cutting bit to allow the shank portion of a broken cutting bit to pass through the rear aperture for removal;
• a sleeve member having a body member and a collar located a tone end of the sleeve member, the body member positioned in the front aperture through a forward end of the front aperture, the body member defining a outer surface, the collar having an inside surface and an outside surface, the inside surface engaged with a contact face of the forward portion to prevent axial movement of the sleeve member in direction toward the rearward portion, the sleeve member further having a bore that receives the shank portion of the cutting bit such that a shoulder on the bit engages the outer surface of the collar;
• and
• an area of interference fit between an inner surface of the front aperture and the outer surface, wherein the sleeve member is retained relative to the forward portion by the area of interference fit, wherein the area of interference fit prevents rotation and axial movement of the sleeve member while in use without urging the sleeve member toward the rearward portion of the bit holder, and wherein the area of interference fit is adapted to allow the axial removal of the sleeve member from the front aperture of the front portion by the manual application of force to the sleeve member.

A cutting tool assembly comprising:

• a bit holder comprising a forward portion, rearward portion, a central opening positioned between the forward portion and the rearward portion, an upper reinforcing portion extending between the forward portion and the rearward portion, and a generally planar mounting surface between the forward and rearward portions positioned on an opposite side of the central opening from the upper reinforcing portion, the forward portion defining a front end and a front aperture having an axis inclined relative to the mounting surface, and the rearward portion having a beveled surface adjacent the mounting surface and defining a rear aperture extending from the beveled surface, the rear aperture having an inner dimension and being open to the front aperture;
• a cutting bit mounted in the front aperture and including a shank portion having an outer diameter and a rearward end accessible through the rear aperture of the bit holder rearward portion and accessible through the central opening, the cutting bit extending beyond the front end, and wherein the inner dimension of the rear aperture is larger than the outer diameter of the cutting bit to allow the shank portion of a broken cutting bit to pass through the rear aperture for removal;
• a cylindrical sleeve member having a body member and a collar located at one end of the sleeve member, the body member positioned in the front aperture through a forward end of the front aperture, the body member defining an outer surface, the collar having an inside surface and an outside surface, the inside surface engaged with a contact face of the forward portion to prevent axial movement of the sleeve member in a direction toward the rearward portion, the sleeve member further having a bore that receives the shank portion of the cutting bit such that a shoulder on the bit engages the outer surface of the collar, the sleeve member including at least two sections forming portions of a cone which are not part of the same cone;
• and
• an area of interference fit between an inner surface of the front aperture and the outer surface, wherein the sleeve member is retained relative to the forward portion by the area of interference fit, wherein the area of interference fit prevents rotation and axial movement of the sleeve member while in use without urging the sleeve member toward the rearward portion of the bit holder, and wherein the area of interference fit is adapted to allow the axial removal of the sleeve member from the front aperture of the front portion by the manual application of force to the sleeve member.