The invention relates to a bit holder for an earth working machine, in particular a road milling machine, that comprises a bit receptacle in the region of a working side of a support member and that indirectly or directly carries an insertion projection on an insertion projection side of the support member, the support member comprising two stripping surfaces [first or second stripping surfaces] that form a stripping surface pair and are at an angle to one another. In order to achieve a stable and long-lived configuration with such a bit holder, provision is made according to the present invention that the support member comprises at least one further stripping surface that is at an angle to the two stripping surfaces of the stripping surface pair.

In such fields as road milling, mining and trenching it is often desirable to engage and degrade tough materials such as asphalt, concrete and rock. To do so, degradation picks comprising hardened distal tips may be secured to an exterior of a movable support such as a rotatable drum or continuous chain so as to be repeatedly brought into contact with a material to be degraded. To secure such degradation picks to the movable support, a block comprising a body with a base surface rigidly attachable to a movable support is disclosed. A first receptacle with a first central axis may be disposed on an external surface of the body and formed to receive a first removable degradation pick. A second receptacle with a second central axis may also be disposed on the external surface and formed to receive a second removable degradation pick where the first and second central axes are nonparallel.

An improved sleeve for securing a milling bit to a milling tool base is described. The base may include a lower portion that mates to a surface milling drum and an upper portion with a borehole that accepts the sleeve. The sleeve may include a deflectable rear portion that may include slot tails. When inserting the sleeve into the front of the borehole, the slot tails on the rear of the sleeve may deflect inwardly. The slot tails may then at least partially return to their resting position as they exit the rear of the borehole to lock the sleeve into place. The sleeve may hold a milling bit.

A milling drum adapted to be rotated in a cutting direction about an axis defined by the cylindrical surface of the drum. A plurality of pairs of overlapping recesses in the cylindrical surface of the drum. A tooth or cutting bit with a base configuration matching a first of the pair of the overlapping recesses, and a lower portion of a side surface including a retainer engagement feature. A retainer has a base configuration matching a second of the pair of overlapping recesses, and a side surface including a tooth engagement feature. A fastener secures the retainer in the second of the overlapping recesses so that the tooth engagement feature of the retainer engages the retainer engagement feature of the tooth or cutting bit to hold the tooth or cutting bit in the first of the overlapping recesses.

A degradation pick or holder shank for facilitating installation, retention and removal is disclosed. The shank may comprise an axially compressive portion that may contract radially when stretched axially and then expand again radially when released. An installation tool may be used to stretch the shank axially during insertion into a bore and then release the shank to retain it within the bore.

A bit holder and corresponding base block are disclosed wherein a slotted shank of the bit holder includes a reverse taper portion adjacent a distal end thereof. A base block with a bore for receiving said shank includes a corresponding hollow portion of reverse taper configuration that will tend to retain said shank therein.

Aspects of the present disclosure relate to an apparatus including a drum rotatable about an axis of rotation and a support mount secured to the drum. The apparatus includes a support mount defining first and second fastener openings and first and second anchor openings. A replaceable holding block mounts to the support mount and the replaceable holding block has a front face and a rear face. The replaceable holding block defines a first fastener opening, a second fastener opening, and a tooth opening that extend through the replaceable holding block from the front face to the rear face. The first and second fastener openings of the replaceable holding block align with the first and second fastener openings of the support mount when the replaceable housing block is mounted to the block mounting surface. A tooth is secured to the replaceable holding block at the tooth opening.

A pick assembly is provided, comprising a bit assembly and a holder assembly; the bit assembly comprising a bit support body, a fastener mechanism and a deflectable member, cooperatively configured such the deflectable member can be deflected responsive to the progressive coupling of the bit support body to the fastener mechanism. The holder assembly comprises a holder body and is configured for accommodating and retaining the bit assembly by interference means. The holder assembly and bit assembly are cooperatively configured such that the retention of the bit assembly by the holder assembly by interference means can be progressively increased responsive to the progressive coupling of the bit support body with the fastener mechanism when the bit assembly is accommodated by the holder assembly, operative to prevent substantial movement of the bit support body relative to the holder body in use.