US 11,045,880 B2 · Boring tool

Abstract

There is provided a undercutting boring tool (10) comprising a bar body (11). A lost motion link consists of a spring (26) selectively compressed by a lost motion rod (27) having a lost motion slot (33) spaced from a drive pin (34). An operating rod portion (36) has a trunnion body (37) at its front end having a pin (41) adapted to engage the lost motion slot (33). A tool carrier (42) forms a pair of spaced flat tines (43) and forms a bearing surface (44) in the bight. The upper tine (43) and the bearing surface (44) section are slotted at (45) to allow the passage of a control link (46). Apertures (47) in the tines (43) engage pins (50) on the trunnion body (37). The bar of a generally H-shaped tool assembly (52) comprises a bearing surface (53) running in the bearing surface (44). A crank portion (54) is connected to the control link (46) via crank pin (55). Drive pins (61) and (62) engage the tool assembly (52) with the end face of the bar body (11) providing positive engagement resisting rotational forces in use. The arrangement allows for post-insertion rotation of the tool assembly (52) from an aligned to a transverse (working) position before engagement of the drive pins (61) and (62).

Claims23

Dependent claims

A boring tool comprising:

a tool bar extending along a long axis;
a tool carrier mounted at a tool mounting end of said tool bar and movable by an operating rod extending along said tool bar;
a cutting tool pivotably mounted to said tool carrier about a mounting axis transverse said long axis and comprising at least a pair of arm portions each extending symmetrically away from said mounting axis to respective cutter portions;
a crank connected to and configured to move said cutting tool between a deployed position having said cutter portions located substantially symmetric about said long axis and a stowed position having said cutter portions laying in a plane substantially aligned with said long axis;
a complementary lug and recess associated with the cutting tool when in said deployed position and an end face of said tool mounting end and selectively engageable by movement of said tool carrier, said crank being operable by said operating rod via a lost motion link selected to force cutting tool stowing only after the complementary lug and recess disengage.

2 more elements

A method of boring a workpiece mounted by one end for rotation on a live centre of a lathe and having a pilot bore therethrough and an expanded starter chamber formed in said pilot bore adjacent another end thereof, the method comprising:

providing a boring tool, the boring tool comprising:
a tool bar extending along a long axis;
a tool carrier mounted at a tool mounting end of said tool bar and movable by an operating rod extending along said tool bar;
a cutting tool pivotably mounted to said tool carrier about a mounting axis transverse said long axis and comprising at least a pair of arm portions each extending symmetrically away from said mounting axis to respective cutter portions;
a crank connected to and configured to move said cutting tool between a deployed position having said cutter portions located substantially symmetric about said long axis and a stowed position having said cutter portions laying in a plane substantially aligned with said long axis;
and
a complementary lug and recess associated with the cutting tool when in said deployed position and an end face of said tool mounting end and selectively engageable by movement of said tool carrier, said crank being operable by said operating rod via a lost motion link selected to force cutting tool stowing only after the complementary lug and recess disengage;
clamping the boring tool in a lathe tool post;
inserting the boring tool through the pilot bore in to the expanded starter chamber;
operating the operating rod to cause the crank to rotate the cutting tool to the deployed position in the starter chamber and bring the cutting tool assembly back until the complementary lug and recess engage;
locking off the operating rod;
operating the lathe and advancing the lathe tool post to bore the workpiece;
stopping the lathe;
backing off the lathe tool post to partially withdraw the boring tool;
unlocking the operating rod;
advancing the operating rod until the complementary lug and recess disengage and the tool carrier advances the cutting tool pivot past the crank pin, rotating the cutting tool to the stowed position;
and
withdrawing the boring tool through the pilot bore.

15 more elements

Dependencies are inferred from the claim text.

Boring tool

Life of this patent

Boring tool

Life of this patent

Abstract

Claims23