PRODUCT MANUAL
Series 70 and 150
Overshots
DOCUMENT
Manual A120
PAGE
42
FISHING TOOLS
11006 Lucerne Street | Houston, Texas 77016 | T: +1 281 219 6613 | Fax: +1 281 219 6638 | [email protected]
Revision: March 2022.
Spiral Grapple
Top Sub
Bowl
“A” Type Packer
Spiral Grapple Control
Guide
Spacer Ring
(only used with Spiral Grapples
and Type A Packers)
Lock Rings
OVERVIEW
Logan Lock Rings provide a posi-
tive means for locking and releasing
straight-threaded, shouldered joints
that will not back off. Lock Rings are
installed between the top sub and the
bowl, and are designed to keep the top
sub from inadvertently unthreading from
the bowl. Lock Rings are typically used
when a significant amount of torque is
being applied through the overshot to
the fish (such as encountered during
back-off operations). Excessive torque
is not necessary when Lock Rings are
used. Lock Rings eliminate the hazard-
ous practices of using steel straps or
install-ing set screws to secure the bowl
to the top sub. Lock Rings can be used
with either a basket or spiral grapples.
CONSTRUCTION
Logan Lock Rings are precision ma-
chined from strees relieved, heat-treated
alloy steel. Lock Rings are used in pairs
and consist of two identical rings with
cam-teeth on one face, knurls on the
other, and two break-out grooves
on the edges.
The pitch of the cam-teeth is greater
than the thread pitch of the bowl. When
reverse rotation is applied, the cam-
toothed edges will wedge against each
other to effectively lock the top sub to
the bowl.
ASSEMBLY
Position the rings together so the break-
out grooves align and the cam-teeth
are intermeshed. Place the lock rings
on the top sub. As the bowl is threaded
and the tool joint made-up, the knurled
faces opposite the cam-teeth will grip
the shoulders.
Heavy make-up torque is not necces-
sary. Joints are properly made up when
reverse rotation is applied and the cam-
teeth shoulders slightly separate.
A spacer is required if the overshot is
dressed with a spiral grapple and a
type A packer. The spacer is installed into
the bowl and on top of the Type A packer.
The spacer fills the void produced by the
extra standoff caused by the top sub and
lock rings. A spacer is not required when
a type A packer is not used.
DISASSEMBLY
A special breakout clamp is required
when unthreading is desired. Slight
right-hand torque may be needed to
align the breakout grooves so they may
receive the clamp. The breakout clamp
consists of two keys that fit into the lock
ring grooves — a lower key seat and
a movable key seat that is attached to
a bracket guide and a screw handle.
A linked chain is attached at one end
to the bracket guide.
Back out the screw handle as far as
it will go. Position the breakout clamp
by placing the keys in the ring grooves
opposite each other. Insert one end
of the linked chain into the hole in the
lower key seat. Pull the chain around
the rings and remove all slack. Slip the
chain pin closest to the pin slot onto
the bracket. Tighten the screw handle
to force both keys into the breakout
grooves. When the grip is broken, the
keys will hold the cam-teeth together
and allow the shoulders to back away
from the knurled faces.
When ordering, please specify:
(1) Part number of the complete
assembly for selected overshot
Lock Rings
and Spacers
