US 4,784,028 AGranted

Mandrel assembly for a portable lathe

AssigneeTri Tool Inc.

InventorWilliam E. Sandford

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Abstract

A mandrel assembly for a portable lathe is disclosed having a clamping system which will accommodate a wide variety of pipe sizes. Jaw blocks are removably attached to the mandrel attaching block to increase or decrease the clamping size of the mandrel. A mandrel mounting head is readily removable from a mandrel shaft so as to provide further variation in clamping size or function. All of the clamp actuating mechanism, as well as the tool feed mechanism is contained within the interior of the mandrel shaft to prevent contamination from external sources, but is readily accessible from the exterior of the mandrel shaft. Laterally spaced apart bearing surfaces between the mandrel attaching blocks and the mandrel mounting head, as well as a torque ring insert interposed between the mandrel shaft and a mandrel adapter provide for the torque reaction between the cutting tool and the mandrel so as to provide a rigid, sturdy base for the cutting tool.

Claims14

Dependent claims

In a mandrel assembly for a portable lathe having a non-rotatable mandrel shaft, a mandrel adaptor non-rotatably and slidably mounted on the mandrel shaft, and a rotatable cutting head supported on the mandrel adaptor the improvements comprising:

(a) a mandrel mounting head attached to a first end of the mandrel shaft, the mounting head defining at least one groove extending in a first plane forming an acute angle with a longitudinal axis of the mandrel shaft and at least one pair of laterally spaced apart, first bearing surfaces located adjacent each side of the at least one groove, each pair of first bearing surfaces being substantially coplanar and extending in a second plane forming an acute angle with the longitudinal axis of the mandrel shaft;
(b) at least one mandrel attaching block located on the mandrel mounting head, the at least one mandrel attaching block having a gripping surface and a pair of laterally spaced apart, second bearing surfaces in slidable contact with the pair of laterally spaced apart first bearing surfaces;
and,
(c) a torque ring insert mounted between the mandrel adaptor and the mandrel shaft to allow relative movement therebetween in a longitudinal direction, but prevent relative rotation therebetween so as to react the torque generated by the rotatable cutting head.

1 more element

A mandrel assembly for a portable lathe having a rotatable cutting head, the mandrel assembly comprising:

(a) a hollow mandrel shaft having a longitudinal axis, a first end to be attached to a pipe and a second end;
(b) a cutting head housing rotatably supporting the rotatable cutting head;
(c) a non-rotatable mandrel adaptor attached to the cutting head housing and slidably attached to the second end of the hollow mandrel shaft;
(d) a torque ring insert mounted between the mandrel adapter and the mandrel shaft to allow relative movement therebetween in a direction generally parallel to the longitudinal axis, but prevent relative rotation therebetween about the longitudinal axis so as to react torque generated by the rotatable cutting head;
(e) feed means to feed the rotatable cutting head in a direction generally parallel to the longitudinal axis;
(f) a mandrel mounting head attached to the first end of the mandrel shaft, the mounting head defining at least one groove extending in a first plane forming an acute angle with the longitudinal axis and at least one pair of laterally spaced apart, substantially flat first bearing surfaces located adjacent each side of the at least one groove, each pair of first bearing surfaces being substantially coplanar and extending in a second plane forming an acute angle with the longitudinal axis;
(g) at least one mandrel attaching block having a gripping surface and a pair of laterally spaced apart, substantially flat second bearing surfaces in slidable contact with the pair of laterally spaced apart first bearing surfaces;
(h) draw bar means extending through at least a portion of the hollow mandrel shaft so as to be movable with respect thereto in a direction generally parallel to the longitudinal axis;
(i) attaching means attaching the at least one mandrel attaching block to the draw bar means;
and,
(j) actuating means interposed between the draw bar means and the mandrel shaft to move the draw with respect to the mandrel shaft thereby moving the at least one mandrel attaching block with respect to the mandrel mounting head so as to increase or decrease the transverse distance between the longitudinal axis and the gripping surface of the at least one mandrel attaching block.

8 more elements

Dependencies are inferred from the claim text.