Rotary retainer for mining bits

A cutter bit holding assembly of a mining machine comprising:

• a cutter bit having a shank portion;
• a support member having a socket for receiving the shank portion of said cutter bit, and a transverse bore relative to the socket extending within said support member partially intersecting the socket thereof define a grooved bore portion immediately adjacent and opening into the socket;
• a rotary locking means positioned within the transverse bore of said support member having turning means and an offset portion positioned within the grooved bore portion adjacent the support member socket for rotation from a first position wherein the offset portion is positioned outside of the socket to permit unencumbered insertion or removal of said bit to a second position wherein the offset portion intersects the socket and engages a locking surface from the shank portion of said cutter bit to securely hold said bit within the socket of said support member;
• and
• retaining means for preventing rotation of said rotary locking means when positioned in its second position engaging the locking surface of said bit.

An improved cutter bit holding assembly of a mining machine of the type in which a support member having a socket therein receives a shank of a cutter bit, wherein the improvement comprises;

• a transverse bore relative to the socket partially intersecting the socket to define a first bore portion on one side of the support member, a second bore portion on the opposite side of the support member, and an intermediate groove portion intersecting the socket and opening thereto;
• a bit groove cut in the side of the shank such that when the cutter bit is positioned within the socket of the support member the bit groove extends in a substantially parallel direction with respect to the transverse bore, the bit groove opening towards the intermediate groove portion of the support member transverse bore;
• a rod coaxially extending into the transverse bore of the support member, the rod having a handle extending exteriorly of the support member for affecting rotation of the rod and an offset portion positionable within the intermediate groove portion of the transverse bore, the rod rotatable from a first position wherein the offset portion thereof is positioned outside the perimeter of the support member socket to permit unencumbered insertion or removal of said bit to a second position wherein the offset portion intersects the support member socket and engages the bit groove of the cutter bit shank to securely hold the cutter bit within the support member socket;
• and
• a resilient bushing member surrounding the portion of the rod and being positionable within the first bore portion of the transverse bore to hold the rod in a substantially coaxial position with respect to the first bore portion, the resilient bushing member acting to constantly urge the offset rod portion securely within the cutter bit groove when positioned in its second position to prevent the accidental removal of the cutter bit from the support member socket.