Tong Assembly for Drill Pipes (Patent No: 876536)

Inventor: Becker, Floyd W.

Location: Calgary

Comments: N/A

Description: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A tong assembly for selectively gripping and releasing a drill-pipe, comprising:
a mounting element for positioning adjacent a drill-pipe without contacting the drill-pipe,
at least one pivotal member mounted on the mounting element to rotate about a pivot axis, the pivotal member having spaced from said pivot axis a pipe-gripping portion which moves toward and into contact with the drill-pipe when the pivotal member rotates in one direction with respect to said mounting element and which moves away from the drill-pipe when the pivotal member rotates in the other direction with respect to said mounting element,
and an inertial element capable of movement with respect to said pivot axis and adapted, upon such movement, to urge a part of the pivotal member to move tangentially about said pivot axis.

2. A tong assembly as claimed in claim 1, in which the mounting element is annular and has a central aperture capable of receiving the drill-pipe without contact, the pivotal member
being mounted to rotate in a plane normal to the axis of the received drill-pipe, the inertial element being annular in shape and being positioned to enclose the drill-pipe and the pivotal member, said part of said pivotal member projecting generally away from the received drill-pipe through an opening in said inertial element, whereby a sudden change in the rotational velocity of the annular mounting element results in a relative rotational movement between the annular mounting element and the inertial element to urge said part of said pivotal member to move tangentially about said pivot axis.

3. A tong assembly as claimed in claim 2, in which there are three pivotal members spaced at 120° intervals around the mounting element, each having a part projecting through a corresponding opening in said inertial element.

4. A tong assembly as claimed in claim 3, in which said annular mounting element has a coaxial shaft extension adapted to be threadedly secured to a power swivel of a drilling apparatus, the tong assembly further comprising a second annular mounting element spaced from said first-mentioned annular mounting element on the side thereof remote from said coaxial shaft extension means rigidly securing said second annular mounting element to said first-mentioned annular mounting element, the inertial element being loosely retained between said annular mounting elements, said pivotal members being mounted between said annular mounting elements.

5. A tong assembly as claimed in claim 2 in which over-toggling biasing means is provided the over-toggling biasing means being adapted to urge the said part of the pivotal member either in one direction to tend to maintain the pipe-gripping portion in contact with the drill-pipe or in the other direction to tend to maintain the pipe-gripping portion away from the drillpipe.

6. A tong assembly as claimed in claim 5, in which said annular mounting element has a coaxial shaft extension adapted to be threadedly secured to a power swivel of a drilling apparatus, the tong assembly further comprising a second annular mounting element on the side thereof remote from said coaxial shaft extension, means rigidly securing said second annular mounting element to said first-mentioned annular mounting element, the inertial element being loosely retained between said annular mounting elements, there being three said pivotal members spaced at 120° intervals between said annular mounting elements, each pivotal member having a part projecting through a corresponding opening in said inertial element.