A bit tip insert on a bit/holder, tool, and/or pick for road milling operations that includes a body including a tip and a base subjacent the tip The bit tip insert also includes at least one heat transfer bore extending from a distal end and/or bottom of the body to a bore termination disposed within the base and/or the tip of the bit tip insert. The at least one bore of the bit tip insert is adapted to allow inward contraction when the overlay transfers heat into the base during operation.

A bit holder having a body that includes a forward end that is diametrically smaller than a lower end and a shank depending axially from the lower end of the body. A substantial portion of the body is substantially solid and the shank is generally cylindrical with a bore axially extending from a distal end of the shank towards the lower end of the body. The bit holder also includes an annular sleeve mounted circumferentially around the upper end of the body and is configured protect the upper end of the body and is configured to receive a bit or insert.

An improved diamond coated bit tip insert on a bit/holder, tool, and/or pick for road milling operations that includes a body including a tip and a base subjacent the tip, the tip including an overlay on an outer surface of the tip. The bit tip insert also includes at least one heat transfer bore extending from a distal end and/or bottom of the body to a bore termination adjacent the tip. The at least one bore of the bit tip insert is adapted to allow inward contraction when the overlay transfers heat into the base during operation.

A rotatable cutting tool (10) includes a cutting tool body (12) having an axial forward end (14) and an axial rearward end (16). A bolster (46) at least partially received in a head portion (22) and includes a convex-shaped head portion (56) with a socket (20), a collar portion (58) and a tapered shank portion (60). The socket (20) is formed with a substantially planar side wall (20a), a bottom wall (20b), and a radius blend (20c). A hard tip or cutting insert (18) is at least partially received in the socket (20) of the bolster (46) and includes a convex-shaped conical head portion (72), a collar portion (74) and an axially-rearward portion (76) that generally conforms to the geometry of the socket (20) of the bolster (46). Between about sixty percent (60%) and about ninety percent (90%) of the cutting insert (18) is received in the socket (20) of the bolster (46), thereby reducing forces and stresses transmitted to the cutting tool (10) during a machining operation.

The invention relates to a bit holder for an earth working machine, in particular a surface miner, a road milling machine, or the like, having a holding projection that comprises a bit receptacle and/or carries a cutting element. In order to improve the operating reliability of an earth working machine, provision is made according to the present invention that the holding projection has, behind the cutting element or behind a receiving region of the bit receptacle in the tool advance direction, a wear protection element having a hard-material element in order to provide an emergency-mode property.

An improved tool is described that has a generally cylindrical slotted shank with a radially bulbous or extending portion adjacent a distal end of the shank, sized to interfere with a bore in which the shank is to be inserted. The dimension of the extending portion can be sized to change the retention force between the shank and the bore as desired. A top of the tool includes a metal carbide-metal disk-metal carbide diamond coated tip sandwich that is bonded inside a bore in the top of the tool.

A method of making a strike construction for a pick tool, a strike construction for a pick tool and a pick tool. The strike construction comprises a strike tip (2) and a support body (20), in which respective attachment ends (10,22) of each of the strike tip and support body are joined to each other, the attachment end of the strike tip is coterminous with cemented carbide material comprised in the strike tip, and the attachment end of the support body is coterminous with cemented carbide material comprised in an end portion of the support body, the end portion being configured such that sides of the support body depend divergently from its attachment end. The method includes providing the strike tip (2) and a precursor body (28) for the support body, in which a proximate end (25) of the precursor body is coterminous with cemented carbide material comprised in an end portion of the precursor body, the end portion of the precursor body being configured such that sides of the precursor body depend divergently from its proximate end, the area of which is less than the area of the attachment end of the support body (20). The method further including processing the end portion of the precursor body to increase the area of the proximate end to that of the attachment end of the support body; and joining the respective attachment ends of the strike tip and the support body to provide the strike construction.

A combination bit and bit holder assembly includes a bit holder having a forward body portion and a shank. The forward body portion includes an upper end and a lower end. An insert is mounted in the bore of the upper end of the body portion. The insert also includes a central bore that receivingly retains a receiving cup. The receiving cup includes a bottom portion and an annular flange that extends from the bottom portion and defines a hollow forward portion. A bit is mounted in the hollow forward portion of the receiving cup which is configured to have a ductility that provides impact absorption to the bit.

A combination bit and bit holder assembly includes a bit holder having a forward body portion and a shank. The forward body portion includes an upper end and a lower end. An insert is mounted in the bore of the upper end of the body portion. The insert also includes a central bore that receivingly retains a receiving cup. The receiving cup includes a bottom portion and an annular flange that extends from the bottom portion and defines a hollow forward portion. A bit is mounted in the hollow forward portion of the receiving cup which is configured to have a ductility that provides impact absorption to the bit.

A cutting tool rotatable about a central longitudinal axis of the cutting tool and configured for impingement upon a substrate includes an elongate cutting tool body having a head and a shank axially rearward of the head. The head includes a cutting member at an axial forward end thereof, a bolster portion axially rearward of the cutting member and a base portion at an axial rearward end of the head. In addition, the bolster portion includes a convex shape section and a generally cylindrical section contiguous with and axially rearward of the convex shape section.