Alignment clamp

Details Alignment clamp Alignment clamp

2001-10-05

2003-11-25

Hail, III, Joseph J. (Department: 3723)

Work holders

Plural holders to hold workpieces relative to each other

Workpieces parallel to each other

C007S139000, C081S003440, C269S131000, C228S049100, C228S049300

Reexamination Certificate

active

06651967

ABSTRACT:

CROSS REFERENCES TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not applicable.
BACKGROUND OF THE INVENTION-FIELD OF THE INVENTION
This invention is directed to the temporary end-to-end alignment of two or more workpieces, such as tubing, pipe, handrail, fittings, shafts, or solid bar, to facilitate their permanent joining, by welding, brazing, soldering, adhesive application, or other physical or chemical means. This invention is intended to fulfill a long-felt need for an alignment device that is light, small, portable, interchangeable, easily maneuverable in confined spaces, and readily usable by pipefitters, millwrights, welders, plumbers, ironworkers, and other practitioners in the fabrication, construction, and repair trades, having a variety of skills and aptitudes.
BACKGROUND OF THE INVENTION-DESCRIPTION OF PRIOR ART
In the fabrication, construction and repair trades, there has persisted a very real problem of pre-positioning and holding a pair of pipe sections together, prior to their joining by welding or other permanent attachment. The problem has been compounded for pipes, fittings, and other workpieces of non-circular cross-section, since the prior art has tended to focus on circular pipe. Pipe sections, tube sections, solid sections, and workpieces of other cross-sections can be quite heavy, and it can be difficult, under the best of circumstances, to align successive sections, to hold a connecting section in exact alignment with, and, in appropriate space relationship with, its prior section. This problem is exacerbated in tight work areas, such as buildings, and with vertical or near-vertical workpieces, such as stack pipes or poles. Small workpieces, at the other end of the spectrum, may be lighter to hold, but harder to handle, due to placement in confined areas, or areas partially or mostly inaccessible to the tradesperson. This situation is complicated when the tradesperson must align and/or attach pipe of varying outer diameters, having the same inner diameter. The situation is also complicated when the tradesperson must align and/or attach various forms of fittings, including, but not limited to, elbows, reducers, tees, crosses, caps, stubs, rings, flanges, and weldments.
Various attempts have been made over the years to address these problems. The earliest attempts used a combination of a C-shaped clamp, an angle iron, and a chain or chain clamp, to effect alignment. Later attempts, such as the devices covered by Hickey U.S. Pat. Nos. 1,848,527, and 1,940,910, issued, respectively, on Mar. 8, 1932 and Dec. 26, 1933, combined a rigid frame, a chain, and a rotatable handle, for restraint of adjacent pipe/pipe joints and adjacent pipe/fitting joints, respectively. However, the heavy, rigid frame and rotatable handle of the Hickey clamps require substantial working room and storage room.
Other attempts in the prior art include U.S. Pat. No. 3,192,804, granted to Peterson on Jul. 6, 1965, for a chain clamp utilizing a locking wrench, and U.S. Pat. No. 4,477,937, granted to Costello on Oct. 23rd, 1984, for a combination pliers, clamp, and wrench, but neither hand tool provides fittings for aligning successive workpieces.
Recent art for pipe alignment devices has evolved along two approaches, the first approach utilizing a rigid, lockable clamp, secured by a single arcuate movement at the perimeter of the pipe, the second approach utilizing a crank-tightened chain. Examples of the first, rigid approach include U.S. Pat. No. 2,846,968, issued to Tipton on Aug. 12, 1958; U.S. Pat. No. 3,422,519, issued to Fehlman on Jan. 21,1969; U.S. Pat. No. 3,467,295, issued to Watson on Sept. 16, 1969; and U.S. Pat. No. 3,952,936, issued to Dearman on Apr. 27th, 1976. The use of rigid clamps, however, is limited to a single size of circular pipe. Furthermore, such clamps have a tendency to be bulky and heavy, especially for larger pipe diameters.
Examples of the second, chain approach, include the following patents:
U.S. Pat. No. 3,593,402, issued to Mori on Jul. 20, 1971
U.S. Pat. No. 3,653,574, issued to Dearman on Apr. 4, 1972
U.S. Pat. No. 3,666,159, issued to Watson on May 30, 1972
U.S. Pat. No. 3,704,503, issued to Haywood on Dec. 5, 1972
U.S. Pat. No. 3,705,453, issued to Olson on Dec. 12, 1972
Further examples can be seen in a series of additional patents issued to Dearman:
U.S. Pat. No. 3,901,497, issued Aug. 26, 1975;
U.S. Pat. No. 3,944,202, issued Mar. 16th 1976;
U.S. Pat. No. 3,952,936, issued Apr. 27th 1976;
U.S. Pat. No. 4,586,647, issued May 6, 1986; and
U.S. Pat. No. 4,726,575, issued Feb. 23rd, 1988.
Unaddressed problems have persisted with the chain approach, nevertheless. Slender, threaded shafts, and intermeshing gear means have been attempted, as disclosed by Mori, but slender shafts have a tendency to break under heavy use, and intermeshing gear means can be difficult to adjust, especially when placed close to the workpiece. Attempts have been made to utilize alignment plates permanently joined to the chain, as disclosed in the Olson and Haywood patents, but permanently-joined plates are not adjustable along the chain, for different sizes of pipe. Other attempts have been made to mount alignment devices on the chain using wires, as shown in the Watson '159 patent, but complications arise from the fragility of the mounting wire, and the lack of bearing area between the chain and the alignment device. The lack of bearing area can lead to rotation and wobble of the alignment device as the chain is tightened.
More recent art for flexible chain clamps is disclosed in the aforementioned Dearman patents, which tend to utilize a combination of jackbars resting on a double or triple chain, the chain held at one end by a pivoting stop, and tightened at the other end by the rotation of a hand crank. Handcranks, however, cannot be fitted in small, congested, or difficult-to-reach workspaces. The jack bars disclosed to date can be complex to make, and easy to abuse and break, due to the number and complexity of their components. The size, weight, and complexity of the various prior-art combinations are ill-adapted for use on non-horizontal workpieces (such as vertical pipe, vertical shafts, or flagpoles), or small size workpieces. A large clamp, and its component crank, can dwarf, or even damage a small workpiece. Excessive lengths of chain can interfere with the operator, particularly in tight spaces. Rotation and wobble of the jackbar can occur during tightening of the chain, due to the gap between the chain and the jackbar, required for movement of the jackbar along the chain.
As alluded to, in the background of the Dearman '
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patent disclosure, cost, weight, and, by extension, complexity, are important considerations in this art. Overall, the prior art has taught towards greater complexity, and has not addressed the possibility of a slidable alignment of jack bar and chain without nuts, screws, or hand tools to adjust.
The prior art has also focused on pipe, to the exclusion of shapes other than circular pipe cross-sections, and has tended to use chain of rectangular cross section, compromising the stability of the alignment apparatus attached to it. In addition, none of the above prior art has addressed the possibility of aligning more than two workpieces at a time.
Moreover, the prior art, as a whole, has tended to align connecting pipe pieces with sharp-pointed screws or nuts. This can create problems for pipe, fittings, and other workpieces made of titanium or other specialty metals, especially where installed in clean environments, such as food processing facilities, semiconductor assembly buildings, or pharmaceutical plants. Sharp-pointed screws, as used in most of the prior art, can create scratches in the stock or pipe, either causing corrosion in the scratch, or allowing impurities to accumulate in the scratch. Swivel feet could be mounted on the screws or nuts, as disclosed in the later Dearman patents, but would add to the cost an

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