Tool for servicing subterranean gate valves

The invention is directed to a tool for removing and replacing the operating nut on a subterranean gate at the bottom of a valve tile. The tool comprises an elongated threaded rod moveably mounted inside of an elongated outer tube and having a threaded nut secured to its upper end. A bifurcated member is affixed to the lower end of the rod. The bifurcated member is configured to fit easily underneath the operating nut for lifting the nut off of the valve stem. A nut retaining member is mounted to the lower end of the tube for holding a new operating nut on top of the bifurcated member during the replacement operation.

BACKGROUND 
1. Field of the Invention 
This invention relates to a tool for servicing subterranean gate valves 
employed in underground utility systems. 
2. Description of the Prior Art 
The problem with subterranean gate valves of the type to which the present 
invention relates is that the operating nut, which is disposed on top of 
the valve casing, corrodes readily over time and loose its shape, that is, 
the nut becomes more round or less square, so that the nut is no longer 
useful for turning the square valve stem for operating the valve. In such 
instances, it may become necessary to excavate the earth around the valve 
tile to expose the valve and replace the valve operating nut. This can be 
a time-consuming and costly procedure. 
In my U.S. Pat. No. 5,638,590, entitled "Tool for Servicing Subterranean 
Gates Valves", issued on Jun. 17, 1997, I disclose and claim a tool for 
removing and replacing the operating nut on a subterranean gate valve 
without having to excavate or otherwise disturb the environment 
surrounding the valve. The tool comprises an elongated shaft having a 
handle at its upper end and a bifurcated member affixed to its lower end. 
The bifurcated member is configured to fit easily underneath the operating 
nut for lifting the nut off of the valve stem. A tubular slide is mounted 
on the shaft and is adapted to impact against a slide stop located below 
the handle. An operating nut retaining member is adjustably mounted to the 
lower end of the shaft for holding a new operating nut on top of the 
bifurcated member during the replacement operation. 
SUMMARY OF THE INVENTION 
The present invention is directed to a tool for servicing subterranean gate 
valves which is an improvement of that disclosed and claimed in my above 
referred U.S. patent, the disclosure of which is incorporated herein by 
reference. The tool differs from the original design in that the tubular 
impact hammer is removed and replaced by an elongated threaded rod 
moveably mounted inside an elongated outer tube. The tube has a threaded 
nut at its outer end and a wrench or ratchet mounted to the nut for 
rotating the threaded rod and effecting movement thereof through the tube 
under a pressure sufficient to remove the operating nut from the gate 
valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawing in detail, the reference numeral 10 denotes a 
subterranean gate valve including a valve body 10a and a valve bonnet 10b 
having a valve stem 10c extending upwardly from the top end thereof. An 
operating nut 9, usually made of cast iron, for example, is removably 
mounted on top of the valve stem 10c for opening and closing the gate 
valve using a conventional socket or wrench. The gate valve 10 is 
typically connected to a utility pipeline (not shown) buried anywhere from 
about three to twelve feet below the pavement 12 of a roadway or the like. 
An elongated, tubular valve tile or box 6 extends downwardly from the 
pavement 12 to the gate valve 10 providing access to the operating nut 9 
for controlling and servicing the valve. A lid or cover (not shown) is 
usually placed over the upper end of the valve box 6 to help keep dirt and 
debris from entering the tile. 
The tool for removing and replacing the valve operating nut 9 according to 
the invention comprises an elongated threaded steel rod 3 moveably mounted 
inside an outer steel pipe 7. The pipe 7 as a threaded fastener or nut 2 
positioned at its outer end and secured to the upper end of the threaded 
rod 3. The rod and pipe should be sufficiently long to extend fully the 
entire length of the valve box 6 from approximately the waist height of 
the operator as shown in FIG. 1. 
At the lower end of the rod 3, there is provided according to the invention 
a bifurcated nut retainer 11 for removing and replacing the valve 
operating nut 9. Preferably, the bifurcated retainer 11 is secured to the 
bottom of the rod 3 by a strong, permanent weld. 
As shown in FIG. 1 and described in detail in my above referred U.S. 
patent, the bifurcated member 11 consists of two elongated prongs 15 and 
16 which are configured and adapted to fit underneath the operating nut 9 
on the valve stem 10c. The prongs are spaced apart a sufficient distance 
to fit around the valve stem 9 and preferably have their inner edges 
inclined inwardly in a direction toward the rod 3. This assures that the 
prongs will easily clear the valve stem and grasp the underneath side of 
the operating nut 9. 
It is important that the two prongs 15 and 16 extend outwardly from the rod 
3 in a substantially perpendicular direction as shown in FIG. 1. This 
configuration makes it easier for the operator to guide the bifurcated 
member 11 underneath the operating nut 9 using the rod as leverage. It is 
also important, for reasons to be made clear hereinafter, to position the 
bifurcated member 11 on the rod 3 with its top flat surface lying in a 
plane that is substantially perpendicular or normal to the axis of the 
rod. 
Spaced from the top surface of the bifurcated member 11 and attached to the 
lower end of the tube 7 is a retainer member in the form, for example, of 
a vertical plate 8 for holding the operating nut 9 on top of the flat 
bifurcated member 11 during the withdrawal and replacement procedure as 
shall be explained. The retainer plate 8 is suitably welded to the end of 
the pipe 7 and is sufficiently long to cover at least a third of the width 
of the operating nut 9. 
To use the tool according to the invention, the operator lowers the tool 
through the open valve box 6 to its bottom end while standing over the box 
opening as depicted in FIG. 1. The operator then maneuvers the tool to 
place the bifurcated member 11 underneath the valve operating nut 9 in the 
manner as described hereinabove. With the two prongs 15 and 16 contacting 
the underside of the operating nut 9, the operator rotates the rod 3 in a 
counter-clockwise direction, for example, with a ratchet 1 moving the rod 
and the bifurcated member upwardly until the plate 8 makes contact with 
the valve stem, applying sufficient axial force against the operating nut 
9 to loosen it from around the valve stem 10c. The operating nut 9 is then 
withdrawn from the gate valve while resting on top of the flat bifurcated 
member in the manner as depicted in FIG. 1. It is of course important that 
the operating nut 9 be kept level on top of the flat bifurcated member so 
that it does not fall off during the removal operation. 
Once the valve operating nut 9 has been fully withdrawn, the old operating 
nut is discarded and a new valve nut is placed on top of the bifurcated 
member 11. The new valve nut is held in place by the vertical plate 8 and 
is then lowered again through the valve box 6 and the new nut is carefully 
placed over the top of the valve stem 10c. The tool 10 is then raised 
again out of the valve box, leaving the new operating nut in place on the 
valve stem 10c for controlling the valve. 
The tool of the invention is simple to construct, easy to use and 
economical to manufacture. While it may typically require thousands of 
dollars in man hours of work and equipment to excavate a subterranean gate 
valve and replace its operating nut, the same procedure can be 
accomplished for a mere fraction of the cost using the instant valve 
servicing tool. 
FIG. 2 shows a modification of the tool according to the invention which 
employs an hydraulic jack as shown in FIG. 2. The jack is provided with a 
bifurcated top plate 18, a base plate 19 and a pressure gage 20. In those 
situations where substantially high pressures are needed to loosen the 
operating nut 9, the modified jack may be placed on top of the pavement 12 
and between the pavement and the upper end of the tool with the bifurcated 
top plate 18 underneath the nut 2. The jack can be made to a standard high 
to accommodate the tool so that the rod and pipe will extend the full 
distance between the operator and the gate valve 10 or means can be 
provided for varying the height of the jack to accommodate valves 
positioned other than the usual distance below the pavement. 
Once the tool has been set up to remove an operating nut in the manner as 
described above and it is determined that the pressure required to remove 
the nut may exceed a certain limit where further pressure may result in 
breakage of the valve or valve stem, then the hydraulic jack may be placed 
underneath the threaded nut 2 of the tool as described and the actual 
pressure applied against the valve nut 9 may be measured so as to not 
exceed the unsafe limit and destroy the valve. In such cases where the 
limit may be exceeded, the operating nut will have to be removed in the 
standard way by excavating the ground around the valve box to remove the 
same and to expose the valve stem for removal of the nut. 
Other features and modifications of the tool of the invention are possible 
without departing from the spirit and scope of the invention. For example, 
it is possible to employ other types of retainer members for holding the 
operating nut on the bifurcated plate such as a removable clamp fitted 
around the rod 3.