Material or article handling – Cylindrical bar handling device – Engaging interior surface of pipe
Reexamination Certificate
1999-09-29
2001-01-16
Krizek, Janice L. (Department: 3652)
Material or article handling
Cylindrical bar handling device
Engaging interior surface of pipe
C294S093000, C414S618000, C414S910000
Reexamination Certificate
active
06174125
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to racking and unracking a pipe. In particular, it relates to a method and apparatus for racking and unracking pipe wherein the apparatus has an expansion sleeve.
BACKGROUND OF THE INVENTION
As shown in
FIG. 1
, pipes
100
are often warehoused in tiered racks
110
. Three tiers are shown in
FIG. 1
, but pipe racks having five or more tiers are common in practice. Typically, the warehouse will have an overhead crane for moving the pipes. However, wrapping a crane sling around a pipe
100
disposed in a rack
110
is difficult, especially if the pipe
100
is not located on the top tier. Therefore, it is necessary to partially withdraw the pipe
100
from the rack
110
before the crane sling is wrapped around it. Prior methods of accomplishing this task were dangerous and often resulted in damage to an end of the pipe
100
.
The present invention eliminates these drawbacks by providing a controllable means for withdrawing the pipe and reducing the possibility of damage to the pipe. The present invention also provides a useful means for inserting a pipe into a rack with minimal risk of damaging the pipe. A number of prior inventions disclose mechanisms for gripping and manipulating tubular structures, but none will perform satisfactorily when used to rack or unrack pipe.
Cullen et al. (U.S. Pat. No. 4,687,244) describe a lifting and reorienting mechanism. The device includes a probe for insertion into an axially extending opening of a structure to be moved. When fully inserted, movement of an outer sleeve deploys tooth-like retractable projections that extend radially from the probe. The retractable projections are forced against the inner wall of the structure to be moved. An important feature of the Cullen et al. device is a dual-arm telescoping actuator that facilitates pivoting of the probe and the structure to be moved. Although this device is capable of performing many useful functions, it is not well suited for the racking and unracking of pipes. The pivoting capability of the device is not required for pipe racking and unracking and might pose a safety hazard should it be accidentally activated. In addition, the retractable projections of the device are likely to damage the inner surface of the pipe.
Marzoli (U.S. Pat. No. 4,777,792) discloses a tube gripping device that is designed to be used in textile machines to automatically replace with empty tubes those tubes that have been wrapped with yarn. The gripping device comprises a substantially cylindrical central steel element that has its lower end of frusto-conical shape and is free to slide axially in a cylindrical gripping element. The cylindrical gripping element has its bottom shaped to receive the lower end of the cylindrical steel element. An axial upward movement of the cylindrical central element forces a localized region of the cylindrical gripping element radially outward, thereby pressing that region of the cylindrical gripping element against the inner wall of the tube. The radially outward movement of the cylindrical gripping element is localized in the vicinity of the frusto-conical lower end of the cylindrical central element. In addition, the radial motion is a direct response to the radial component of the force exerted on the cylindrical gripping element by the frusto-conical lower end of the cylindrical central element. The localized nature of the gripping force is not desirable for the pipe racking and unracking application being considered herein.
Mistrater et al. (U.S. Pat. No. 5,322,300) describe several variants of a device for supporting hollow cylinders while they are coated with an electrophotographic-imaging layer. The devices comprise an elongated arm with a shaft extending therethrough. The shaft includes a presser means at one end. An expandable disk shaped member is coaxially aligned with and slidably mounted on the shaft between the presser means and an end of the elongated arm. In an undeformed state, the expandable disk shaped member fits in a hollow cylinder with a preferred clearance of about 250 micrometers (0.01 in). Expansion of the disk shaped member is achieved by compressing the member between the presser means and the end of the elongated arm. Additional features of the Mistrater et al. device ensure that a constant force is applied to the hollow cylinder in spite of temperature variations. However, the Mistrater et al. device fails to provide a means for self-orienting the device coaxially with the hollow cylinder.
SUMMARY OF THE INVENTION
The present invention includes a method for racking and unracking pipe and a device to facilitate the process. For the case in which a pipe needs to be removed from a rack (unracking), the method involves providing a pipe gripper having an expansion sleeve and inserting the pipe gripper into an accessible end of a pipe. After insertion, the pipe gripper is activated, thereby forcing the expansion sleeve against an inner wall of the pipe. With the expansion sleeve pressed against the pipe inner wall, the pipe gripper moves so as to slide a portion of the pipe off the pipe rack. With one end of the pipe supported by the pipe gripper and the other end still supported by the pipe rack, a crane sling is attached to the pipe and the pipe is further manipulated off the rack. The use of a forklift coupled to the pipe gripper further facilitates the process. The new method eliminates the dangerous conditions of prior unracking methods and also avoids the need to repair pipe ends.
The case in which a pipe is to be inserted onto a rack (racking) is similar to the unracking process. In the racking process, a pipe that is supported in a crane sling is manipulated so as to place a first end of the pipe on the rack. A pipe gripper having an expansion sleeve is inserted into an accessible end of the pipe and the crane-sling support is removed. The pipe gripper is activated, thereby forcing the expansion sleeve against an inner wall of the pipe and the pipe gripper then moves so as to slide the pipe fully onto the pipe rack. To facilitate the processes, a sophisticated pipe gripper is used. The pipe gripper comprises an expansion sleeve having a distal end a proximal end, and a bore therethrough. A proximal pressure plate abuts the proximal end of the expansion sleeve. A nosepiece is located at the distal end of the expansion sleeve. The nosepiece assists in orienting the pipe gripper coaxially with a pipe to be gripped. A mandrel passes through the bore of the expansion sleeve and is attached to the nosepiece. Tension in the mandrel axially squeezes the expansion sleeve between the nosepiece and the proximal pressure plate. The squeezing forces a radial expansion of the expansion sleeve against an inner wall of the pipe. When pressed against the inner wall of the pipe, the expansion sleeve frictionally couples the pipe to the pipe gripper, thereby allowing the pipe to be moved along its axis.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be obtained by means of instrumentalities in combinations particularly pointed out in the appended claims.
REFERENCES:
patent: 3134620 (1964-05-01), Blaisdell
patent: 4050731 (1977-09-01), Coone et al.
patent: 4173368 (1979-11-01), Haverbusch
patent: 4410210 (1983-10-01), de Sivry et al.
patent: 4687244 (1987-08-01), Cullen et al.
patent: 4777792 (1988-10-01), Marzoli
patent: 5090758 (1992-02-01), Lord
patent: 5186477 (1993-02-01), Nakazawa et al.
patent: 5221099 (1993-06-01), J{umlaut over (a)}nsch
patent: 5322300 (1994-06-01), Mistrater et al.
patent: 5468116 (1995-11-01), Reichert et al.
Cave Loren C.
Davis Marney L.
Stevenson Donald R.
Wallace George H.
Bryant Joy L.
Krizek Janice L.
Newport News Shipbuilding & Dry Dock Company
Singer Bart A.
LandOfFree
Method and apparatus for racking and unracking pipe does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for racking and unracking pipe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for racking and unracking pipe will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2490320