Tools – Wrench – screwdriver – or driver therefor – Handle or shank
Reexamination Certificate
2000-02-16
2001-12-11
Hail, III, Joseph J. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle or shank
Reexamination Certificate
active
06327940
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
None.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to the use of safety handles that are placed about the periphery of heavy equipment to protect the operator's hands from injury. More particularly, the invention relates to safety handles that are mounted to the periphery of manual pipe tongs, which are typically used in the oilfield drilling industry. More particularly still, the invention relates to multi-piece, reinforced, and replaceable handles for manual pipe tongs that protect oilfield workers' hands from injury that might otherwise result from impact with adjacent equipment.
2. Description of the Related Art
Manual pipe tongs are used throughout the oilfield industry to apply torque to various tubular components of generally cylindrical shape. This application of torque is most often used to secure, tighten (make-up), and loosen (break-out) the threaded rotary connections of drill pipe, drilling collars, casing and tubing. Pipe tongs typically function by incorporating a cantilevered configuration that holds the workpiece in a grip that tightens or loosens depending on the direction that torque is applied to the lever arm.
FIG. 1
shows a typical prior art manual tong assembly
10
as used in oilfield drilling operations to secure or rotate a cylindrical workpiece
12
. Manual tong assembly
10
includes a long jaw
14
, a short jaw
16
, a lug jaw
18
, and a lever arm
20
all connected together at pivot points
22
a, b, c, d.
A latch
24
is pinned to one end of the long jaw
14
and fits into a receiver step
26
at the end of the lug jaw
18
.
FIGS. 2
a
and
2
b
show how different workpiece
12
sizes can be accommodated by adjusting the lengths and configurations of lug jaw
18
.
FIG. 2
a
shows the lug jaw
18
of
FIG. 1
that includes an array of mounting locations
28
and a choice of receiver steps,
26
and
30
, that may be used to adjust the manual tong apparatus
10
to various diameters of workpiece
12
(e.g. pipe diameters). Alternatively,
FIG. 2
b
details a lug jaw
32
that is longer in length and includes a hinged portion
34
attached to the lug portion
36
by means of a hinge pin
38
so as to allow even larger diameter workpieces to be accommodated by tong assembly
10
.
Referring again to
FIG. 1
, jaws,
14
,
16
, and
18
are positioned in place around workpiece
12
and locked into place with latch
24
. In some instances, each jaw may contain one or more sets of sharpened teeth called tong dies
40
that are used to “bite”) into workpiece
12
and prevent slippage when manual tong
10
is engaged. Once latch
24
is engaged, lever arm
20
can be rotated in direction &agr; so as to load latch
24
in tension and engage and apply torque to workpiece
12
in that direction. Rotating lever arm
20
in direction &ohgr; will loosen the grip of jaws (
14
,
16
, and
18
) on workpiece and allow latch
24
to be opened. Because tool
10
is quite large, with lever arm
20
typically being 3-6 feet long, operation usually requires more than one person. Several handles, such as
42
or
44
, are typically placed about the periphery of manual tong assembly
10
to provide locations for rig workers to guide it when moving tong assembly
10
into position on the pipe, or to remove it from the pipe.
Manual tong
10
, as illustrated, is configured to grip workpiece
12
only when torque is applied in the &agr; direction. Typical rig operations incorporate two sets of manual tongs, with each being a mirror image of the other, so that one tightens in clockwise direction and the other in a counter-clockwise direction. Each can tighten or loosen the pipe threads, depending on whether it is installed in the upper position and engages the pin (male) connection or the lower position for engaging and holding the box (female) counter. Typical operations will include the use of two, opposed tongs. When more than one tong is used, their positions on the workpiece relative to each other depends on the operation being performed and the type of additional rig equipment used.
Operators typically position and manipulate manual tongs
10
by grabbing handles that are provided about the periphery of the tongs as, for example, handles
42
and
44
in FIG.
1
.
FIGS. 3
a,
3
b,
and
3
c
show three different designs of tong handles that have been previously known and used on manual tong assemblies.
FIG. 3
a
shows a manual tong apparatus that includes a handle
50
made from U-shaped a cylindrical rod that has been cast or welded onto the body
52
of the tong. To manufacture handle
50
, the cylindrical rod is bent into top, middle, and bottom sections
54
,
56
,
58
, respectively. Although this design is the simplest and most cost effective for a manual tong manipulator handle, it offers the least protection to the operator, as a hand wrapped around handle
50
is exposed to blows from above, below, or horizontally.
In order to gain maximum protection from injury while using tongs with a handle of this design, the operator must fight his natural tendency to place his hands on top
54
and bottom
58
portions and must grip only middle portion
56
of handle
50
. This is because serious injury can result to an operator's hands when he is manipulating one set of tongs around the pipe while another set of tongs is being manipulated around the pipe, either above or below his tongs. If an operator's hand is exposed while two sets of adjacent tongs move relative to each other, it can be pinched or crushed between the tongs. The design of
FIG. 3
a
offers little protection from injuries of this type, as the operator is comfortably able to grip the handle in any number of unsafe ways.
FIG. 3
b
demonstrates a handle system
60
that is designed to prevent the type of hand injuries experienced while using the design of
FIG. 3
a.
Handle
60
includes a tong body
62
with a rod-style handle
64
as before, but with the addition of metal guard plates positioned in a horizontal plane of each end of vertical handle
64
. Metal guard plates
66
and
68
are intended to both restrict placement of hands to the center section of handle
64
and to protect the operator's hands from being crushed or impaled by an adjacent tong or other nearby equipment. Metal plates
66
and
68
can be either cast or welded into place as original equipment when the tong body
62
is manufactured or can be retrofitted to existing tongs as a safety upgrade. While the addition of metal plates
66
,
68
is an improvement to the handle assembly
50
of
FIG. 3
a,
they do not offer any shock absorbing characteristics. If an operator were to have a hand resting upon metal plates
66
,
68
and that hand were to be impacted by another object, it is possible that the operator's hand or fingers could become crushed or severed. To ensure that tong handle devices pose as little safety risk as possible, it is best that they be manufactured or retrofitted with shock absorbent devices.
FIG. 3
c
shows another embodiment for a tong handle, which utilizes a one-piece polyurethane dumbbell-shaped design to address the shock absorbency concerns of handle
60
of
FIG. 3
b.
Polyurethane dumbbell
70
is attached to tong body
72
by cutting out middle portion
56
in
FIG. 3
a
and utilizing horizontal portions
54
and
58
(
74
and
76
in
FIG. 3
c
). One-piece dumbbell
70
includes a generally cylindrical handle section
78
with disc shaped flange portions
80
,
82
above and below handle section
78
. Holes are drilled for spring pins in the ends of horizontal members
74
and
76
, and one-piece dumbbell
70
is fitted onto horizontal members
74
and
76
. Separate spring pins,
84
,
86
are driven through opposite ends of dumbbell handle
70
, to engage horizontal members
74
and
76
and hold dumbell
70
in place on tong body
72
. Flanged portions
80
are preferably larger in diameter than an operator's fist so that they are able to act as large bumpers to protect
Conley & Rose & Tayon P.C.
Hail III Joseph J.
National-Oilwell L.P.
Thomas David B.
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