US3566507A

US3566507A - External aligning tool for pipes or the like

Info

Publication number: US3566507A
Application number: US743656A
Authority: US
Inventors: Helmuth H Jacobsen
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-07-11
Filing date: 1968-07-10
Publication date: 1971-03-02
Anticipated expiration: 1988-03-02
Also published as: FR1575995A; GB1232042A

Abstract

AN EXTERNAL ALIGNING TOOL FOR TUBES, RODS OR LIKE WORKPIECES COMPRISES A RIGID OR DEFORMABLE CARRIER WHICH SUPPORTS SEVERAL CLAMPING UNITS EACH OF WHICH COMPRISES ONE OR MORE PAIRS OF ARMS MOVABLE TOWARD AND AWAY FROM EACH OTHER ABOUT A PIVOT AXIS DEFINED BY THE CARRIER. THE ARMS HAVE BEAKED CLAMPING PORTIONS MOVABLE INTO OR AWAY FROM ENGAGEMENT WITH A WORKPIECE WHICH IS PLACED BETWEEN THE ARMS OF THE RESPECTIVE CLAMPING UNIT. THE DRIVE MEANS FOR PIVOTING TE ARMS CAN INCLUDE A SEPARATE DRIVE FOR EACH PAIR OF ARMS OR A SINGLE DRIVE WHICH CAN MOVE ALL OF THE ARMS SIMULTANEOUSLY OR SERIATIM. THE CARRIER CAN COMPRISE TWO PIVOTALLY AND LONGITUDINALLY ADJUSTABLY CONNECTED PORTIONS EACH OF WHICH CARRIES A CLAMPING UNIT.

Description

7 Sheets-Sheet 1 Inventor:

Hclmu'ih H. Jacobsen mm 11M his Attorney H. H. JACOBSEN EXTERNAL ALIGNING TOOL FOR PIPES OR THE LIKE m I 3 ll? ll ll I E H EYX WY! 1 3 m Na 39m j i 7 T i Sm 32% n 22 NE E 2 E 3% mi i a N? E March'z, 1971 Filed Ju 1y 10. 1968 H. H. JACOBSEN 3,566,507

EXTERNAL ALIGNING TOOL FOR PIPES OR THE LIKE 7 Sheets-Sheet n Rm i8 i8 7 S k8 RE 5 .U V O an v Q as 5 MM mw mwmf- 1 mg RNQ Aw "QM A. m m v 3? wi Mg an R March v2, 1971 Filed July 10, 1968 In wantor:v Helmuth H. Jacobsen L/ /7 his Allprney EXTERNAL ALIGNING TOOL FOR PIPES OR THE LIKE 7 Sheets-Sheet 5 Filed July 10, 1968 Inventor: Helmufh H. Jacobsen b *ZM/fl/ MW.

his Allorney EXTERNAL ALIGNING TOOL FOR PIPES OR THE LII (E Filed July 10. 1968 March 2, 1971 H. H.JACOBSEN I v 7 Sheets-Sheet 4 Inventor.-

I his vAllar-ney H. H. JACOBSEN 3,566,507 EXTERNAL ALIGNING TOOL FOR PIPES OR THE LIKE "r Sheets-Sheet 5 5 t W3 E- 1 q. fi Q .L... 3 3 3 3 Ex g 5 2 8 W QE QE 5 m? a ESQ S 3 1 v \5 e -27 m @m 1: a w .1 f5 2 12 2 n m b, 2/4. 1 w ia x Y 5/ I M F l. mi 8. 3 3W5 & 8 3% w m E March 2, 1971 Filed July 10, 1968 Inventor:

Helmulh HJacobsen by w z /0!/ his Allorney March 2, 1971 H. H. JACOBSEN 3,566,507

EXTERNAL ALIGNING TOOL FOR PIPES OR THE LIKE .7 Sheets-Sheet 6 Filed July .10, 1968 In ventar HelmuthHJacobscn v Z/d g/f (54%,

his Aliorney United States Patent 3,566,507 EXTERNAL ALIGNING TOOL FOR PIPES OR THE LIKE Helmuth H. Jacobsen, 53 Bonn 1, R0. Box 88, Post Luftelberg, Germany Filed July 10, 1968, Ser. No. 743,656 Claims priority, application Germany, July 11, 1967, R 46,449; May 17, 1968, P 17 52 385.2 Int. Cl. B23 1 19/00 US. Cl. 29-200 30 Claims ABSTRACT OF THE DISCLOSURE An external aligning tool for tubes, rods or like workpieces comprises a rigid or deformable carrier which supports several clamping units each of which comprises one or more pairs of arms movable toward and away from each other about a pivot axis defined by the carrier. The arms have beaked clamping portions movable into or away from engagement with a workpiece which is placed between the arms of the respective clamping unit. The drive means for pivoting the arms can include a separate drive for each pair of arms or a single drive which can move all of the arms simultaneously or seriatim. The carrier can comprise two pivotally and longitudinally adjustably connected portions each of which carries a clamping unit.

BACKGROUND OF THE INVENTION The present invention relates to improvements in external pipe aligners, flange aligners, lineup clamps and analogous tools which can be utilized to engage and to temporarily hold two or more tubular and/or rod-like work-pieces in predetermined angular positions with reference to each other. More particularly, the invention relates to improvements in tools which can be utilized for centering, aligning and properly gripping tubes, pipes, rods, bars and/or analogous workpieces during treatment, for example, during welding of two or more workpieces to each other, during temporary termination of ,a connection between workpieces, for temporary assembly of workpieces into a skeleton frame, and for many analogous or related purposes. Still more particularly, the invention relates to tools which are especially suited for use in clamping of pipes, tubes, rods or like workpieces during welding or other treatment and which are arranged to engage the external surfaces of such workpieces.

External aligning tools and line-up clamps are often used as substitutes for internal aligners, particularly for holding and gripping of tubular workpieces whose internal diameters are too small for insertion of internal aligners. Furthermore, external aligning tools are used for proper alignment of tubular workpieces with rod-like workpieces or for clamping and alignment of two or more rod-like workpieces.

Presently known external aligning tools are not entirely satisfactory, mainly because they are not sufficiently versatile. Thus, known external aligners cannot properly grip workpieces of relatively small external diameter, for example, small-diameter pipes which are used in steam boilers, central heating systems, steel pipe manufacturing plants, hydraulic and pneumatic systems of machine tools and the like. External aligners which are used for assembly of pipelines normally comprise rings each of which consists of two hingedly connected semicircular sections, When properly engaging a tube or a rod, each ring extends all the way around the workpiece. This is undesirable for many reasons, particularly when the entire circumference of a workpiece is not accessible. Moreover, a fully open ring which consists of two hingedly "ice connected semicircular sections occupies too much room so that it cannot be slipped over a workpiece which is already built into a boiler or another apparatus. Still further, much time is lost for opening, closing and renewed opening of rings if the ring sections are moved by mechanical means. The frames which connect two or more rings of a conventional aligning tool are bulky and cannot be fitted into small areas when the tool is used in a machine, boiler or other apparatus, for example, to clamp two pipes prior and during welding of such pipes to each other. An additional drawback of just described conventional aligning tools is that they are not sufficiently versatile because a two-piece ring can only be used for clamping of pipes or rods Whose external diameter is Within a very narrow range. In other words, such rings can eventually compensate for minor tolerances in the caliber of pipes or rods so that it is necessary to keep a large supply of tools with rings of different internal diameter. Furthermore, conventional external aligning tools can be used only for clamping of pipes or like workpieces in such positions that the workpieces are coaxial with each other. Therefore, such tools cannot be used to hold pipes which must be joined to form a V, a T, an elbow or an analogous connection wherein the portions make an angle which exceeds or is less than degrees. Tools which are used to hold pipes at an angle other than 180 degrees normally resemble a vise with two pairs of jaws wherein at least one pair of jaws is movable with reference to the other pair and wherein the jaws of each pair must be moved toward or away from each other in order to engage or release a pipe or a rod. This consumes much time and the tool is quite heavy and bulky so that its usefulness is rather limited. Furthermore, such vise-like tools are not suited for highly accurate axial alignment of workpieces so that the operator must carry or have ready several types of tools in order to perform work which necessitates clamping of workpieces in axial alignment as well as at an angle of less than 180 degrees. The jaws of the vise are reciprocable in relatively short ways in order to reduce the weight of such tool; this causes frequent jamming and affects the accuracy of alignment. As a rule, proper manipulation of two pairs of jaws in a vise-like aligning tool necessitates at least ten discrete steps which consume much time so that such tools failed to gain widespread acceptance. Another drawback shared by all or nearly all presently known external aligning tools is that they are not sufliciently accurate, i.e., too much depends on the skill and carefulness of the operator.

SUMMARY OF THE INVENTION It is an object of my invention to provide a versatile, accurate and simple external aligning tool which can 'be utilized to properly engage and hold rod-like and/ or tubular workpieces of circular or other outline, which can be used to clamp workpieces preparatory to or during welding, to clamp workpieces which are to be assembled to form a temporary frame, rack, shelf or the like, to hold and clamp parts of fully or partially assembled machines or apparatus in hard-to-reach areas, to hold two or more workpieces in positions of axial alignment or at any desired angle with reference to each other, and/or to clamp workpieces of different and/ or identical external diameters with the same degree of accuracy.

Another object of the invention is to provide an external aligning tool whose accuracy can be adjusted at will, which can be converted with little loss in time for clamping of workpieces in different positions of inclination with reference to each other, which can be used for proper alignment of telescoped workpieces, which requires little room for application to or disengagement from workpieces, whose manipulation can be mastered by persons having little skill, which can be applied to or removed from workpieces with little loss in time, which can clamp workpieces with a readily adjustable and ac curately determinable force, and which can be readily taken apart and/or reassembled by resorting to rudimentary tools.

A further object of the invention is to provide an aligning tool which can be operated by hand or by one or more motors, which can engage two or more workpieces serially or simultaneously, which can be transported and stored in a small area, which can be used in the welding of T, L-shaped, V-shaped or otherwise configurated connections between tubes and/or rods, and which provides ample room for access to meeting abutting or telescoped parts of workpieces while such workpieces are held in requisite positions for welding or other treatment.

An ancillary object of the invention is to provide a novel main support, novel work-engaging elements and a novel drive for an external aligning tool which can be used for clamping of tubular and/or rod-like workpieces of any desired length or cross-sectional area.

The improved external aligning tool is particularly suited for aligning and/or gripping of pipes, tubes, rods, bars or analogous workpieces. It Comprises one-piece or composite carrier means, a plurality of clamping units each including a pair of arm means supported by the carrier means for pivotal movement about a common pivot axis, clamping portions provided on the arm means and each having a plurality of projections facing the pr jections of the other clamping portion and a recess between such projections, and drive means for pivoting the arm means of the pairs of arm means in opposite directions to move the projections of the clamping portions toward and away from engagement with workpieces which are located therebetween. The clamping portions preferably resemble open beaks and the rescesses between their projections are preferably flanked by concave faces of the respective clamping portions which are preferably mirror symmetrical with reference to a plane including the corresponding pivot axis. The drive means is preferably arranged to move the arm means at the same rate of speed and through identical distances. However, the tool may be provided with means for facilitating or effecting adjustment of one arm means in at least one clamping unit with reference to the other arm means.

If the carrier means is a rigid piece of solid or tubular stock, the arm means of all clamping units are preferably arranged to pivot about a single pivot axis which can be defined by a single pivot member or by a series of pivot members mounted in the carrier means. However, it is also possible to employ a deformable carrier means, for

example, a carrier means comprising two poritions which are pivotable and/or movable lengthwise with reference to each other and each of which supports at least one clamping unit. Such aligning tools can be used in forming of Ts, Vs or analogous connections between pipes or rods.

If the drive means is arranged to move all of the arm means in response to manipulation of a single handle or the like, it may comprise a spindle which is rotatable and axially movable in a hollow tubular carrier means and can transmit motion to cones each of which cooperates with followers provided on the arm means to pivot such arm means in response to displacement of the spindle, either simultaneously or in a desired sequence.

The drive means may also comprise a separate drive for each clamping unit. In such tools, each drive may comprise a spindle with left-hand and right-hand threads which mesh with spindle nuts mounted on the arm means of the respective clamping unit. The spindles may be rotated by hand or 'by means of a suitable prime mover. For example, each drive may comprise a fluid-operated motor which is operatively connected to the arm means of the respective clamping unit by a link train.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved external aligning tool itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partly elevational and partly sectional view of an aligning tool which embodies one form of the invention, the section being taken in the direction of arrows as seen from the line I-I of FIG. 2;

FIG. 2 is a composite sectional view taken along the lines II-II and IIaIIa of FIG. 1;

FIG. 3 is a transverse sectional view of a second tool, substantially as seen in the direction of arrows from the line IIIIII of FIG. 4;

FIG. 4 is a fragmentary elevational view of the second tool;

FIG. 5 is a transverse sectional view of a third tool, substantially as seen in the direction of arrows from the line V-V of FIG. 7;

FIG. 6 is a longitudinal sectional view of the third tool, substantially as seen in the direction of arrows from the line VIVI of FIG. 7;

FIG. 7 is a partly elevational and partly sectional view of the third tool, with certain parts broken away, the section being taken in the direction of arrows as seen from the line VIIVII of FIG. 6;

FIG. 8 is a fragmentary central longitudinal sectional view of a fourth aligning tool, the section being taken in the direction of arrows as seen from the line VIII-VIII of FIG. 9; and

FIG..9 is a sectional view as seen in the direction of arrows from the line IX-IX of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 2, there is shown an aligning and holding or clamping tool which is utilized to grip two tubular workpieces A35, B35 in such a way that the workpieces abut against each other end-to-end, for example, for the purpose of welding. FIG. 1 shows that the diameters of the workpieces need not be identical.

The tool comprises three essential parts, namely, a rigid one-piece main support or carrier 1 and two clamping or aligning units A, B which are spaced from each other in the axial direction of workpieces A35, B35 and each of which can clamp the respective workpiece. The clamping units A, B are supported by the carrier 1. Since the two clamping units are of identical design, only one of these units will be described in full detail. The numerals denoting parts of the clamping unit A are preceded by characters A and the numerals denoting the corresponding parts of the unit B are preceded by characters B. The clamping unit A comprises two arm means respectively including pairs of grippers or aligning arms A2, A5 and A3, A4 the upper or first end portions of which are of arcuate shape and are provided with registering openings or holes A6, A9 and A7, A8 receiving a pivot member All) which is installed in the carrier 1. The pivot member A10 extends through three coaxial bores or holes All of the carrier and is secured thereto by one or more pins, screws or analogous fasteners. This pivot member extends across two recesses or cutouts A12, A13 which flank a projection or web A14 of the carrier. The recess A12 receives the curved first end portions of arms A2, A3 and the recess A13 accommodates the curved first end portions of arms A4, A5. It will be noted that the arms A2, A5 flank the arms A3, A4 and that the arms A2, A5 and A3, A4 respectively extend from opposite sides of the carrier 1. The pivot member B10 for the first end portions of arms B2-B5 in the clamping unit B is coaxial with the pivot member A10; if desired, these pivot members can be replaced by a single pivot member (not shown) or each of the pivot members A10, B may comprise two coaxial portions. For example, the pivot member A10 may comprise a first portion which serves as a fulcrum for the first end portions of arms A2, A3 and a second portion which extends through the holes A8, A9 of the arms A4, A5.

The second end portions or clamping portions A- A18 of the arms A2-A5 serve to engage the external surface of the workpiece A35, and the configuration of such clamping portions is best shown in FIG. 2 which illustrates the clamping portions B15, B17 of the arms B2, B4. The clamping portions B15, B17 resemble open beaks and are respectively formed with two projections or fingers B15, B15" and B17, B17" which define between themselves two recesses fianked by concave edge faces of the respective arms. The projections B15, B15" and B17, B17" extend toward the adjoining lateral sides of the carrier 1, i.e., in the same direction as the respective first end portions which are pivotable on the member B10.

Those portions of projections B15, B17 which engage the workpiece B35 are bounded by convex faces. The work-engaging faces of the projections B15", B17" are slightly convex or flat. The convex portions of the projections B15, and B17, follow carefully designed curves. The configuration of the clamping portions AIS-A18 of the arms A2-A5 and of the clamping portions of the arms B3, B5 is the same as that of the just described clamping portions B15, B17. It will be noted that the clamping portions of arms A2, A5 are mirror symmetrical to clamping portions of arms A3, A4 with reference to a plane which includes the axis of the pivot member A10.

The intermediate portions of arms A2, A5 are rigidly connected to each other by a distancing sleeve A19 and by suitable bolts and nuts shown in FIG. 1. A similar distancing sleeve connects the arms A3, A4 (see the Sleeve B20 in the clamping unit B of FIG. 1 and in the lefthand portion of FIG. 2). The purpose of such distancing sleeves is to insure accurate alignment of the clamping portions of arms A2, A5 and A3, A4. For all practical purposes, the arms A2, A5 form a rigid gripper or arm means which is fulcrumed at A10. The same holds true for the arms A3, A4. The arms A2, A5 further carry a blockshaped spindle nut A21 which is provided with trunnions A22, A22 turnable in the arms A2, A5. The spindle nut A21 is installed between the distancing sleeve A19 and the pivot member A10, and the common axis of its trunnions A22, A22 is parallel to the axis of the pivot member A10. This spindle nut is provided with right-hand internal threads. The spindle nut whose trunnions are journalled in the arms A3, A4 is not shown in FIGS. 1 and 2; this spindle nut corresponds to the spindle nut B23 in the clamping unit B and is provided with left-hand internal threads. The spindle nut B23 is turnable about the common axis of two trunnions B24 which are rotatable in the arms B3, B4.

The two spindle nuts of the clamping unit A (namely, the spindle nut A21 and the one corresponding to the spindle nut B23) mesh with right-hand and left-hand external threads provided in a spindle A25 (see the threads B25, B25" of the spindle nut B25 in FIG. 2). The spindle A25 extends across an elongated slot A26 in the carrier 1 and is movable between the open and closed ends of this slot in response to pivotal movement of the arms A2, A5 and A3, A4 toward or away from each other. The spindle A25 is held against tilting with reference to the carrier 1 in a manner as shown in FIG. 2 for the spindle B25. This spindle carries two annular washers B27, B27 which flank the carrier 1 at the op posite sides of the slot B26 to insure that the axis of the spindle B25 remains normal to the plane of the carrier 1 while the spindle is free to travel between the ends of the slot B26. The right-hand threads B25 of the spindle B25 mesh with the internal threads of the spindle nut B21 and its left-hand threads B25" mesh with the internal threads of the spindle nut B23. The right-hand end of the spindle B25, as viewed in FIG. 2, extends beyond the spindle nut B21 and can be non-rotatably inserted into the socket B28 of a cranked handle B29 by means of which the spindle can be rotated in a clockwise or in a counter-clockwise direction. The socket B28 can be permanently afiixed to the spindle B25 if the handle B29 is separable therefrom. It is further clear that the socket B28 and the handle B29 can be permanently aflixed to the spindle B25 or that the latter can be rotated by other suitable manually turnable or motor-operated means. The parts B21, B23, B25, B28, B29 constitute one of two drives in the tool of FIGS. 1 and 2, and the two drives together constitute a drive means which can move the arm means A2, A5 and A3, A4 of the clamping unit A and the arm means B2, B5 and B3, B4 of the clamping unit B in opposite directions.

The spindle nut B23 comprises three coaxial sections of different external diameter and is rotatable in a bearing sleeve B23 having the aforementioned trunnions B24 which are mounted in the arms B3, B4. The left-hand end face of the sleeve B23 has an axially extending detent pin B30 which can snap into one of several blind bores or notches B31 provided in the annular shoulder of the median section of the spindle nut B23. A package of dished springs B32, held by a split ring B33, biases the sleeve B23 toward the notches B31. The just described parts B30-B33 permit pivotal movements of the arms B3, B4 with reference to the carrier 1 independently of the arms B2, B5. Such pivotal movements are necessary or desirable when the tool is utilized to align two workpieces of other than circular outline or to align a cylindrical workpiece with a second workpiece of partly cylindrical and partly polygonal outline. The holes for the trunnions B24 are elongated or enlarged to permit pivotal movement of the arms B3, B4 with reference to the carrier 1 While the position of the spindle B25 with reference to the slot B26 remains unchanged. Once the adjustment of arms B3, B4 with reference to the carrier 1 is completed, the trunnions B24 are engaged by suitable stops (not shown) to prevent them from sliding in the holes provided therefor in the arms B3, B4. The outermost section of the spindle nut B23 is knurled or milled so that it can be readily rotated by hand or by means of a tool in order to change the angular position of arms B3, B4 with reference to the carrier 1 while the position of the arms B2, B5 remains unchanged. The just described parts constitute but one of several devices which can be employed to change the position of arms B3, B4 with reference to the carrier 1 while the position of the arms B2, B5 with reference to the carrier remains unchanged. The median section of the spindle nut B23 may carry a scale whose graduations register with the notches 31 to facilitate adjustment of the spindle nut B23 with reference to the spindle B25.

The carrier 1 has a centrally located rounded aperture 34 which is disposed between the clamping units A, B and serves to receive a portion of a vise or another holder which supports the tool during application to a pair of solid or tubular workpieces. Furthermore, the aperture 34 may serve as a means for facilitating suspension of the tool on a nail, hook or post during storage or in transportion.

The operation is as follows:

By rotating the handle (not shown) of the drive for the clamping unit A, the operator can move the arms A2, A5 and A3, A4 away from each other to provide room between the clamping portions AIS-A18 so that such clamping portions can loosely accommodate a portion of the workpiece A35. The handle is thereupon rotated in the opposite direction to pivot the arms A2-A5 in a sense to move their respective clamping portions toward the adjacent sides of the workpiece A35. The spindle nut A21 then travels away from the handle, i.e., toward the carrier 1, and the other spindle nut (corresponding to the spindle nut B23) moves toward the spindle nut A21, i.e., toward the carrier 1 but also toward the handle. During rotation of the handle in a sense to move the clamping portions of arms A2, A5 and A3, A4 toward each other, the spindle A25 travels downwardly toward the open end of the slot A26 and is guided by washers corresponding to the washers B27, B27. These washers slide along the sides of the carrier 1 to prevent tilting of the spindle A25. The recesses of the clamping portions A-A18 approach the external surface of the workpiece A35 and the projections of the clamping portions A15-A18 engage such workpiece to automatically hold the latter in a predetermined position in which the axis of the workpiece is parallel to the axes of the pivot member A10 and trunnions A22, A22 as well as to the common axis of trunnions which carry the second spindle nut corresponding to the spindle nut B23 of FIG. 2. The axial position of the clamping nut A with reference to the workpiece A35 is preferably such that the latters right-hand end portion (FIG. 1) extends to a plane which is located substantially midway between the clamping units A and B. The handle which turns the spindle A25 is preferably rotated with a substantial force to insure that the projections of the clamping unit A with reference to the workpiece A35 is a requisite force in order to prevent axial displacement and/or wobbling of the workpiece during welding.

The second clamping unit B is manipulated in the same way. Thus, the arms B2, B5 are moved away from the arms B3, B4 to provide room for the workpiece B35 and the handle B29 is then rotated in opposite direction to move the spindle nuts B21, B23 toward each other, i.e., toward the adjoining sides of the carrier 1, until the projections of the clamping portions of the arms B2-B5 engage the workpiece B35 and hold it in axial alignment with the clamped workpiece A35. If the adjoining ends of the workpieces A35, B35 are to be welded to each other, the operator must provide a requisite welding gap between such ends, i.e., he must determine the minimum distance between the workpieces A35, B35 prior to tightening of the arms B2-B5 against the workpiece B35. The arms A2-A5 and B2-B5 can properly center workpieces of identical or different external diameters. If the external diameter of one of the workpieces is less than the internal diameter of the other workpiece, the two workpieces can be telescoped into each other prior to final clamping. The welding action may be a tack welding action or it may produce a ring-shaped seam all the way around abutting ends of the workpieces A35, B35. .The welding flame can be applied in a single operation all the way around the meeting ends of the workpieces. It is also possible to shift the tool axially or circumferentially of the workpieces during welding. Upon completion of the welding operation, the two handles are rotated in a sense to move the arms A2-A5 and B2B5 away from the respective workpieces so that the tool can be shifted axially toward the other end of the workpiece A35 or B35 in order to facilitate welding of such other end to a third workpiece, not shown. Also, the tool is then ready to be stripped off the workpieces by moving it axially beyond the other end of the workpiece A35 or B35 in order to employ it for welding of a second pair of workpieces. If there is no room for movement of the tool all the way to and beyond the other end of the workpiece A35 or B35, the handles are rotated in a sense to move the arms A2- A5 and B2-B5 apart until the tool is ready to be removed in the radial direction of the workpieces.

As stated before, and as shown in the left-hand portion of FIG. 2, the tool is preferably provided with a device which renders it possible to pivot one pair of arms in each clamping unit with reference to the carrier 1 independently of the other pair of arms in the same clamping unit. Thus, the arms B3, B4 can be pressed in a direction toward the carrier to withdraw the detent pin B30 from the adjoining notch B31, and the spindle nut B23 is then rotated by hand or by a tool with reference to the spindle B25 in order to select a different angular position of the arms B3, B4. At least that notch B31 which receives the pin B30 when the arms B2, B5 are mirror symmetrical to the arms B3, B4 with reference to the plane of the carrier 1 is marked by a symbol or the like to facilitate rapid return movement of arms B3, B4 to such position.

An important advantage of the tool is that the arms A2-A5 and B2B5 are pivotable on the carrier 1 which renders it possible to automatically clamp the workpieces A35, B35 in axial alignment with each other. This is in contrast to the operation of conventional aligning tools which employ reciprocable jaws. The spindles A25, B25 insure uniform movement of arms in the respective clamp ing units toward or away from each other so that the workpieces can be aligned with a high degree of precision. These spindles form part of indirect motion transmitting connections between the arms of the respective clamping units. The configuration of work-engaging faces on the clamping portions 15-18 of arms in the clamping units A and B is such that the workpieces A35, B35 are automatically aligned (i.e., moved into positions of axail alignment with each other) despite the fact that the arms pivot about axes defined by the members A10, B10. The arrangement is such that the common axis of two workpieces is located at a predetermined distance from the common axis of the pivot members A10, B10 regardless of the diameters of such workpieces. In other words, the distance between the common axis of the members A10, B10 and the common axis of the workpieces held by arms A2-A5 and B2-B5 is the same even if the workpiece A35 and/ or B35 is replaced by a workpiece of larger or smaller external diameter. The position of arms B3, B4 with reference to the arms B2, B5 is changed if the operator desires to clamp two workpieces in positions in which the axis of one workpiece is parallel to but does not coincide with the axis of the other workpiece.

The cross-sectional outline of the carrier 1 can be selected at will. FIG. 1 shows that the carrier is of generally rectangular outline; however, it is equally possible to employ tubular or rod-shaped carriers, or carriers of polygonal outline with rounded or facetted edges. The slots A26, B26 can be replaced by elongated slots which are closed at both ends or by circular or otherwise configurated openings as long as the washers (such as those shown at B27, B27) are large enough to prevent tilting of spindles during movement toward or away from the respective pivot members. The configuration of arms 2-5 can be changed at will as long as their clamping portions 15-18 are capable of properly centering workpieces therebetween. As stated before, the clamping portions B15, B17 to FIG. 2 resemble open beaks; it can also be said that such clamping portions resemble portions of a human hand if the projection B15 or B17 is to constitute the thumb and the projection B15" or 17" constitutes an eX- tended index finger.

The width of the arms (as considered in the longitudinal direction of the carrier 1) is of no particular importance. The arms should not be too wide because this would add to the bulk and weight of the tool. It is further clear that each of the clamping units A and B may comprise a pair of arm means each of which comprises a single relatively wide arm or more than two arms. This will be understood with reference to the clamping unit of FIG. 1 by visualizing a fifth arm which is rigid with the arms A2, A5 and is located in front of the workpiece A35 and a sixth arm which is rigid with the arms A3, A4 and is located behind the workpiece A35. The distance between the arms A2, A5 or A3, A4 should not be too small because this could affect the accuracy of alignment of the workpieces. Moreover, the arms A2, A5 and/or A3, A4 could consist of a single piece of metallic or other suitable rigid material. In other words, and referring again to FIG. 1, the arms A2, A5 and the distancing sleeve A19 could form integral parts of a metallic arm means. It is equally within the purview of my invention to employ clamping units wherein the arms of each arm means are movable toward and away from each other in the longitudinal direction of the carrier. For example, the distancing sleeve A19 of FIG. 1 could be replaced by a distancing element which is capable of moving or permitting movement of the arms A2, A5 toward or away from each other. The trunnions A22, A22 are then long enough to remain in their respective holes irrespective of the selected distance between the arms A2, A5. The width of the recesses A12, A13 is then increased in the axial direction of the pivot member A to permit movement of the first end portions of arms A2, A5 toward each other. Each of the arms A2, A5 can be pivotally coupled to the adjoining arm A3, A4 so that the distance between the arms A3, A4 changes automatically in response to a change in distance between the arms A2, A5. Such adjustments can be carried out in order to increase the accuracy of alignment (by moving the arms apart) or to reduce the overall dimensions of the tool (by moving the arms toward each other) so that the tool can be readily manipulated in a small area. Each of the arms or at least the clamping portion of each arm is preferably detachable from the carrier so that it can be replaced by a different arm or by a different clamping portion, or that it can be repaired or cleaned when necessary. The tool can be furnished with two or more sets of spare arms or spare clamping portions and the arms or clamping portions of each set may have different dimensions, different configurations, different strength characteristics, different widths and/ or other criteria. For example, at least one set of spare arms may be provided with toothed, milled, knurled or otherwise roughened work-engaging faces. Also, at least one set of arms may consist of magnetic or magnetizable material so that they can adhere to magnetizable or magnetic workpieces. The carrier 1, too may consist of magnetic or magnctizable material, or it may carry one or more magnets so that it can adhere to a metallic supporting surface without resorting to hooks, nails or other types of suspending devices.

If it is desired to move the clamping units A and B nearer to or further away from each other, the carrier 1 is replaced with a carrier of variable length. This can be achieved in a number of ways. For example, and referring to FIG. 1, the carrier 1 may comprise two portions which are slidably telescoped into each other so that the clamping unit A can be moved in parallelism with the common axis of the pivot members A10, B10 toward or away from the clamping unit B, or vice versa. The carrier then comprises means for temporarily, i.e., releasably, fixing its two portions against longitudinal movement with reference to each other when the clamping units A and B are located at a desired distance from each other. Such a tool can be used with advantage when it is necessary to provide more room at the point where two workpieces abut against each other to facilitate welding or other treatment. Also, the two clamping units can be moved further apart to properly grip pipes which have relatively long unsupported portions; the tool is then adjusted so that each clamping unit grips and clamps a pipe close to its center, namely, at a point which is remote from the abutting ends of such pipes. It is also possible to equip a onepiece or a two-piece carrier with three or more clamping units; for example, the carrier of FIGS. 1 and 2 can be provided with four clamping units, two for each workpiece, with three clamping units, or with five or more clamping units. The same holds true for tools which employ composite carriers or variable length. Each portion of a composite carrier may carry two or more clamping units and the distance between the clamping units which are mounted on either portion of the carrier may but need not be the same. The same applies for clamping units which are mounted on a rigid one-piece carrier.

Still further, the carrier of FIGS. 1 and 2 can be replaced with a rigid one-piece L-shaped or V-shaped carrier whereby each leg of such carrier can support one, two

10 or even more clamping units. Tools having V-shaped or L-shaped carriers can be employed for clamping and hold ing of workpieces which must be joined to each other in order to form an L-joint, V-joint or an analogous connection between rod-like or tubular parts.

FIGS. 3 and 4 illustrate a portion of a second tool which can be utilized to clamp two workpieces A135, B in such positions that their axes make an angle of more or less than degrees. Furthermore, the tool of FIGS. 3 and 4 is equally useful to clamp two workpieces A35, B35 or A135, B135 in axial alignment with each other. The two clamping or aligning units of the tool shown in FIGS. 3 and 4 are identical or analogous to the clamping units A, B of FIGS. 1 and 2. However, this second tool employs a different main support or carrier which comprises two portions A1, B2 pivotable with reference to each other about an axis which is normal to the pivot axes of the two clamping units (see the pivot members A10, B10). All such parts of the second tool which are identical with the corresponding parts of the tool shown in FIGS. 1 and 2 are denoted by similar reference characters. The clamping unit A is mounted on the portion A1 and the clamping unit B is mounted on the portion B1 of the carrier. The portion A1 is bifurcated, as at A36, and defines a slot which receives a tongue B38 of the portion B1. One prong of the bifurcated part A36, namely that prong which is nearer to the handle A29, is provided with a circular scale 37 adjacent to an index 37B on the portion B1. The parts A36, B38 are provided with registering holes 39 for a shaft 40 which resembles a bolt and carries a nut 41 to provide an adjustable pivotal connection between the portions A1 and B1. A detent pin 40' extends into a blind bore of the head of the shaft 40 and into one of several blind bores in one prong of the bifurcated part A36 to locate the portions A1, B1 in desired angular positions with reference to each other.

The manner in which the arms A2A5 and B2-B5 of the clamping units A, B in the tool of FIGS. 3, 4 are manipulated to move with reference to the two-piece carrier A1, B1 is the same as described in connection with FIGS. 1 and 2. By releasing the nut 41 so that the pin 40' can be withdrawn from the blind bore of the shaft 40, the operator can change the angular position of portions A1, B1 with reference to each other in order to change the angle which the axes of the workpieces A135, B135 make with each other when such workpieces are properly engaged and held by the arms A2 A5 and B2-B5. It is also within the purview of the invention to connect the portions A1, B1 in such a way that the axis of the shaft 40 is normal to the pivot members A10, B10 as well as to the axes of the spindles A25, B25. This merely involves changing the positions of parts A36, B38 so that the plane of the part B38 is normal to the plane of FIG. 4. The unit A or B is then movable behind or in front of the plane of FIG. 4 about an axis which is located in such plane. In other words, and as shown in FIGS. 3, 4, the shaft 40 can be mounted in such a way that the pivot members A10, B10 remain in a common plane regardless of the angular positions of portions A1,

B1 with reference to each other. Alternatively, and as mentioned above, the shaft 40 can be installed in such a way that the pivot member A10 can be moved into or away from the plane of the pivot member B10, or vice versa.

When the tool of FIGS. 3 and 4 is used to hold and center two coaxial workpieces, e.g., the workpieces A35, B35 of FIGS. 1 and 2, the operator adjusts the position of portions A1, B1 with reference to each other so that the axis of the pivot member A10 coincides with the axis of the pivot member B10. When the portions A1, B1 assume the positions shown in FIGS. 3 and 4, i.e., when the axis of the pivot member A10 is inclined with reference to the axis of the pivot member B10, the tool can be used to clamp portions of an elbow or to hold two rod-like or tubular workpieces in a desired position of inclination of their axes with reference to each other. The workpieces A135, B135 can constitute rods or tubes and their diameters may but need not be the same. Furthermore, these workpieces may but need not be straight. In the illustrated clamped positions, the workpieces A135, B135 are ready to be welded, brazed or soldered to each other.

Referring to FIG. 4, the numeral 39' denotes an elongated slot which can be provided in the tongue B38 and/ or in the prongs of the bifurcated part A36 as a substitute for the corresponding hole 39. This slot 39' enables the operator to change the overall length of the carrier, i.e., to reduce or increase the distance between the pivot members A10, B while the angular position of the portions A1, B1 with reference to each other remains unchanged. In other words, the tongue B38 can pivot as well as slide with reference to the bifurcated part A36. The slot or slots 39' may be provided in the tool of FIGS. 34 as well as in the aforementioned modification of such tool wherein the axis of the shaft 40 is normal to the axes of pivot members A10, B10 and to the axes of spindles A25, B25. It is further clear that the portion A1 can be detached from the portion B1 so that each of these portions (and the corresponding clamping unit A or B) can be used independently of the other portion, for example, to clamp a single tubular or rod-like workpiece as a substitute for a vise or the like.

When the portions A1, B1 are arrested against pivotal movement with reference to each other in a position in which the carrier resembles an L-shaped body, the tool of FIGS. 3 and 4 can be used in the same way as described hereinbefore in connection with too-ls having rigid L-shaped or V-shaped carriers. The distance between the shaft 40 and the two clamping units shown in FIG. 4 can be increased, either by employing portions A1, B1 of greater length or 'by replacing the portions A1, B1 with portions of variable length, so that the right hand clamping unit B of FIG. 4 can be pivoted clockwise about the axis of the shaft 40 until the pivot members A10, B10 make an angle of 90 degrees (for welding of pipes which form an L or a T) or an acute angle. The number and distribution of holes provided in the bifurcated part A36 for the detent pin 40' can be selected in such a way that the portions A1, B1 can be fixed in a series of predetermined angular positions, for example, when such portions make angles of 90, 60, 45 and Alternatively, a ratchet or the like can be provided to automatically terminate angular movement of portions A1, B1 with reference to each other when the two portions make an angle which is customary between two pipes or rods, e.g., an angle of 45 or 60". The detent pin can be replaced by other suitable detent devices, for example, by the detent means B30-B33 of FIG. 2.

The tool of FIGS. 3 and 4 can be further modified in a number of ways, for example, by utilizing therein a carrier which is of variable length and comprises tWo or more pivotally connected portions. Some shortening and lengthening of the carrier can be effected by utilizing the slot 39' of FIG. 4; however, and as mentioned before, each of the portions A1, B1 can comprise two or more parts which are telescoped into or slidable along each other and each of which can carry at least one clamping unit so that the distance between such clamping units can be changed or that the operator can change the distance between a selected clamping unit and the shaft 40. Still further, the shaft 40 can be replaced by a universal joint which permits the portion A1 to swivel in all directions with reference to the portion B1, or vice versa. Such universal joint (for example, any known ball-and-socket joint) enables the operator to select the angle between the axes of the pivot members A10, B10 at will and contributes considerably to the versatility of the tool.

FIGS. 5 to 7 illustrate a third tool wherein the drive means comprises a single drive which serves to move the arms of both clamping units with reference to each other.

This tool comprises a hollow tubular carrier 201 one end of which is closed by a plug 201 and which accommodates an elongated spindle 25. The right-hand end portion of the spindle 25 is threaded, as at AB25, and meshes with a sleeve having internal threads 46. The outer end portion of the sleeve 45 carries a handle 29 which comprises two discrete portions, see FIG. 7. The left-hand end portion of the spindle 25 carries a conical motion transmitting member B42 (hereinafter called cone) and an intermediate portion of the spindle 25 is surrounded by a second motion transmitting cone spindle 25 is surrounded by a second motion transmitting cone A42. The tips of the cones A42, B42 face toward each other and their larger-diameter end portions are slidably guided in the carrier 201. The cone A42 is slidable along the spindle 25; the other cone B42 is compelled to share all axial movements of the spindle. As best shown in FIGS. 6 and 7, the cone A42 has a cylindrical extension or hub 43 provided with a circumferential groove 44. The left-hand end face of the sleeve '45 abuts against the annular shoulder A42 of the cone A42 and has a blind bore which accommodates the extension 43. A radial screw or pin 47 extends through the sleeve 45 and into the groove 44 to couple the parts 45, A42 to each other for axial movement with reference to the spindle 25. However, the sleeve 45 is free to rotate with reference to the extension 43. A threaded stop 48 extends radially inwardly into the open left-hand end portion of the tubular carrier 201 to prevent withdrawal of the cone A42.

The carrier 201 is provided with a radially extending projection or web (here shown as comprising two portions A49 and B49) which serves as a holder for the pivot members A210, B210 of the two clamping units. These clamping units respectively comprise arms A202- A205 and B202-B205 which are respectively provided with holes A20*6A209 and B206-B209 for the corresponding pivot members A210, B210. The bores of the portions A49, B49 are respectively shown at A211, B211 and the portion B49 is further provided with two recesses B212, B213. The portions A49, B49 of the Web can be soldered, welded or otherwise rigidly secured to the tubular part of the carrier 201. They are located in a common plane which includes the axis of the carrier 201. If desired, the portions A49, B49 can be replaced by a single one-piece web. FIG. 7 shows that the manner in which the pivot member B210 is mounted in the portion B49 is the same as shown in FIG. 1 for the member B10. Thus, the portion B49 has two recesses B212, B213 which accommodate intermediate (not end) portions of the respective arms B202, B203 and B204, B205. On the other hand, the portion A49 is narrower and accommodates only a median portion of the pivot member A210. The intermediate portions of arms A202-A205 are held on the end portions of the pivot member A210 by suitable split rings or the like. However, it is clear that the portion A49 can be replaced by a portion which is identical with the portion B49, or vice versa.

The first end portions B50, B53 of the arms B202, B205 are rigidly connected to each other by a distancing member B54 which extends into the interior of the carrier 201 (see particularly FIG. 6) and constitutes a follower for the cone B42. It has a conical face B56 which engages the peripheral surface of the cone B42. A second distancing member or follower B55 has a conical face B57 which also engages the cone B42 and this second follower is rigid with the first end portions B51, B52 of the arms B203, B204. The end portions B-B53 extend beyond the pivot member B210 (see FIG. 7) and into cutouts B58, B59 of the carrier 201, such cutouts also receiving portions of the aforementioned followers B54, B55. The followers A54, B54 between the first end portions A50, A53 and A51, A52 of the arms A202, A205 and A203, A204 have faces A56, A57 which engage the peripheral surface of the cone A42. The cutouts of the carrier 201 for the followers A54, A are shown in FIG. 6, as at A58, A59.

An intermediate portion of the spindle 25 extends through and is rigidly screwed or bolted to a cylindrical guide member 60 having an axially parallel flute 61 which receives the stem of a screw '62 threaded into the carrier. The length of the flute 61 determines the extent to which the guide member 60 and spindle 25 can move axially back and forth with reference to the carrier 201. The guide member 60 is located between the cones A42, B42. The screw 62 holds the guide member 60 and spindle 25 against rotation with reference to the carrier 201.

The operation of the tool shown in FIGS. and 7 is as follows:

The operator rotates the handle 29 in a clockwise direction to draw the threaded portion AB of the spindle 25 into the sleeve 45. The cone B42 shares such rightward axial movement of the spindle 25 and causes the arms B202, B205 to pivot with reference to the arms B203, B204 because the cone B42 engages the faces B56, B57 of the distancing members or the followers B54, B55. The sleeve 45 bears against the shoulder A42 of the cone A42 so that the latter moves with reference to the spindle 25, i.e., in a direction to the left, as viewed in FIG. 6 or 7. In other words, the cones A42, B42 travel toward each other to move the clamping portions of the arms A202, A205 toward the clamping portions of the arms A203, A204 and to simultaneously move the clamp ing portions of the arms B202, B205 toward the clamping portions of arms B203, B204. The clamping portions B217, B218 of arms B204, B205 are shown in FIG. 7 which also shows the projections B217, B217" and B218, B218" of such clamping portions. The arms of both clamping units pivot about the common axis of the pivot members A210, B210. When the clamping portions of the arms B202-B205 engage the peripheral surface of a rod-like or tubular workpiece B235 (FIG. 7), pivotal movement of these arms with reference to the member B210 is terminated but the sleeve 45 can be rotated further in order to move the clamping portions of arms A202,-A205 toward each other so that such clamping portions can grip and hold a second workpiece (not shown) of smaller external diameter, for example, the workpiece B35 of FIG. 1 if the external diameter of the workpiece B235 shown in FIG. 7 exceeds the external diameter of the workpiece B35. The operator notes a rapidly rising resistance to further rotation of the handle 29 when the cone A42 has moved to a position (to the left, as viewed in FIG. 6 or 7) in which it causes the clamping portions of arms A202-A205 to bear against the peripheral surface of the second workpiece. The two workpieces are then held in positions of axial alignment with each other and can be readily welded to each other in the same way as described in connection with FIGS. 1 and 2. Of course, if the clamping portions of arms A202-A205 engage a workpiece prior to engagement between the workpiece B235 and the clamping portions of arms B202-B205, lengthwise movement of the cone A42 is terminated ahead of lengthwise movement of the cone B42. It will be seen that the guide member 60 and the screw 62 render it possible to use the tool of FIGS. 5-7 for alignment of workpieces having identical or different external diameters. The axial movement of cone A42 or B42 is terminated prior to axial movement of the other cone when the diameters of the workpieces are difierent. It is clear that the cones A42, B42 need not come to a halt at the same time when the diameters of the two workpieces are identical.

The drive means for the arms A202-A205 and B202- B205 can include a power operated device, i.e., the handle 29 can be replaced by a pneumatic or hydraulic motor (not shown) which can rotate the sleeve 45 with reference to the spindle 25. Also, the spindle 25, cones A42, B42 and sleeve 45 can be replaced by a drive means which comprises a train of gears, chains and sprockets, or the like. The drive means of FIGS. 5.to 7 is preferred at this time because it is simple, accurate and undergoes little wear; furthermore, nearly all of its parts can be readily accommodated in and protected by the carrier 201.

Referring finally to FIGS. 8 and 9, there is shown a portion of a tool wherein the arms of each clamping unit can be pivoted by separate drives each of which includes a fluid-operated motor. The carrier of this tool comprises several portions or sections including a hollow main portion of polygonal outline and lugs 101, 102, 103, 104 which respectively support two

coaxial pivot members

10, 10". It will be noted that FIG. 8 and 9 show only one of the two clamping units in this tool, i.e., the pivot members 10', 10" correspond to the pivot member A10 or B10 of FIGS. 1 and 2. The

lugs

101, 102 and 103, 104 respectively define

recesses

12, 13 for the first end portions of

arms

2, 3 and 4, 5 which are respectively provided with

holes

6, 7 and 8, 9 for pivot members 10', 10". The lug 101 is connected to the corresponding lug for the other clamping unit (not shown) 'by one or more elongated checks or walls 99 (one shown in FIG. 8). These cheeks contribute to rigidity of the carrier. The clamping portions of arms 2-5 are similar to the clamp ing portions AIS-A18 shown in FIG. 1. FIG. 9 merely shows the projections 15', 15" and 16', 16" which form part of clamping

portions

15, 16 of the

arms

2 and 3.

The

arms

2, 5 are rigidly connected to each other by a distancing sleeve 19 and by suitable bolts and nuts. A similar distancing sleeve 20 connects the

arms

3 and 4. The distancing

sleeves

19, 20 respectively maintain the clamping portions of

arms

2, 5 and 3, 4 in accurate alignment with each other and they also respectively prevent movements of

arms

2, 5 and 3, 4 toward or away from each other.

The carrier is provided with two guide slots 26 which extend at right angles to the common axis of pivot members 10', 10" and are formed by two pairs of

guide plates

105, 106 which are welded to the main portion 100 of the carrier directly opposite the lugs 101-104.

The aforementioned fluid-operated motor of the drive for the arms 2-5 comprises a hydraulic cylinder 107 which is preferably of the double-acting type and has a piston rod 108 which is normal to the pivot members 10', 10". The cylinder 107 is mounted on the main portion 100 of the carrier midway between the

pivot members

10, 10" (see FIG. 8). The piston rod 108 extends toward and between the guide slots 26; its lower end portion is bifurcated, as at 109, to hold a shaft 110 which is parallel to the pivot members 10', 10". The shaft 110 extends into the respective slots 26 and at its ends carries

trunnions

111, 112 which are respectively coupled to links 113', 113" and 114', 114". As shown in FIG. 9*, the links 113', 113" are respectively provided with sets of holes or

openings

115, 115', 115" and 116, 116', 116" each of which can accommodate a

shaft

22 or 23. The shaft 22 connects the

arms

2, 5 between the distancing sleeve 19 and the pivot members 10', 10", and the shaft 23 connects the arms 3-, 4 between the, distancing sleeve 20 and

pivot members

10, 10". The maximum distance between the clamping portions of

arms

2, 5 and 3, 4 can be changed by changing the elfective length of links 113', 113" and 11-4, 114", i.e., by mounting the

shafts

22, 23 in the openings 115', 116' or 115", 116". The links 114', 114" are also formed with several holes so that their effective length can be changed in the same way as that of the links 113', 113".

The main portion 100 of the carrier (or one of the aforementioned cheeks 99) supports an eye 34" which can be engaged by the jaws of a vise or which can be used as a means for suspending the tool on a nail, hook or the like in storage or during transportation.

The operation of the tool which embodies the structure of FIGS. 8 and 9 is as follows:

.The lower chamber of the cylinder 107 (as viewed in Fl GS. Sand 9) receives pressurized fluid through a suitable system of valves (not shown) so that the piston moves the piston rod 108 upwardly whereby the links 113'114" move the clamping portions of arms 25 away from each other. In the next step, fluid is admitted to the upper chamber of the cylinder 107 so that the piston rod 108 moves downwardly and reduces the angle between the

links

113', 113 and 114, 114". The piston rod 108 acts upon the shaft 110 which extends into and slides in the slots 26. The bifurcated end portion 109 of the piston rod 108 can move the shaft 110 to such position that its axis is coplanar with the axes of

shafts

22 and 23, i.e., the links then make an angle of 180 degrees. Depending on the diameter of the workpiece 35, its peripheral surface is engaged in one of several angular positions of the

links

113, 113" and 114, 114" with reference to each other. The projections of the clamping portions of arms 25 center the workpiece 35 so that this workpiece is coaxial with the workpiece which is gripped by the other clamping unit of the tool. It is clear that the system of valves which control the flow of fluid to and from the chambers of the cylinder 107 can be used to simultaneously control the admission of fluid to the chambers of the other cylinder. Alternatively, only the pump which feeds fluid to the cylinder 107 can be employed to deliver fluid to the other cylinder. It is further clear that the carrier including the main portion 100 can support three or more clamping units so that the tool can properly hold three or more workpieces, for example, to hold the ends of a centrally located workpiece in abutment with and coaxially to two outer workpieces. The same applies for the tools of FIGS. l2 and 5-7.

The tool of FIGS. 8 and 9 can be used with particular advantage for clamping and centering of bulky workpieces, i.e., of workpieces with large diameters so that the manipulation of a handle or the like to move the

arms

2, 5 and 3, 4 with reference to each other would require too much time. The extent to which the arms are movable with reference to each other can be determined in advance by insertion of

shafts

22, 23 into selected openings or holes of the links. In this way, the piston rod 108 must be moved through relatively short distances in order to move the arms into requisite clamping engagement with a workpiece of known external diameter or with workpieces whose external diameters are within a known range.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. An external aligning tool for pipes or analogous workpieces comprising carrier means; a plurality of clamping units each including a pair of arm means supported in the region of one end thereof on said carrier means for pivotal movement about a common pivot axis and each having opposite said one end a free end, said arm means comprising clamping portions each having a plurality of projections facing the projections of the other clamping portions and a recess between such portions; and drive means connected to said arm means between said one end thereof and said projections thereon for pivoting said arm means of said pairs in opposite directions to move the projections of said clamping portions toward and away from engagement with workpieces which are located therebetween, whereby such workpieces may be introduced for engagement with said projections between said free ends of said arm means.

2. A tool as defined in claim 1, wherein said clamping portions resemble open beaks and wherein said recesses are flanked by concave faces of the respective clamping portions, at least one projection of each clamping portion having a convex work-engaging face.

3. A tool as defined in claim 1, wherein said drive means is mounted on said carrier means and comprises means for moving the arm means of said pairs at the same rate of speed and through identical distances.

4. A tool as defined in claim 28, wherein each of said linkages comprises at least one pair of links and wherein each link of each of said pairs is articulately connected to the respective piston rod and to one of the arm means in the respective clamping unit.

5. A tool as defined in claim 1', wherein the arm means of all of said clamping units are pivotable about a single pivot axis.

6. A tool as defined in claim 1, wherein the pivot axis of at least one clamping unit is inclined with reference to the pivot axis of at least one other clamping unit.

7. A tool as defined in claim 1, wherein said carrier means comprises means for changing the position of the pivot axis of at least one of said clamping units with reference to the pivot axis of at least one other clamping unit.

8. A tool as defined in claim 1, wherein each arm means of at least one of said clamping units comprises a plurality of arms.

9. A tool as defined in claim 1, wherein said carrier means is provided with at least one cutout for each of said clamping units and wherein the arm means of each clamping unit have end portions received in the respective cutout and being turnable therein about the respective pivot axis.

10. A tool as defined in claim 1, wherein each arm means of at least one of said clamping units comprises a pair of arms spaced from each other in the direction of the respective pivot axis and wherein the arms of one arm means are disposed between the arms of the other arm means in said one clamping unit.

11. A tool as defined in claim 1, wherein the distance between the axis of a workpiece of circular outline which is engaged by the clamping portions of one of said clamping units and the respective pivot axis is constant regardless of the diameters of such workpieces.

12. A tool as defined in claim 1, wherein said clamping portions of each of said clamping units are arranged to maintain the axes of cylindrical workpieces in parallelism with the respective pivot axes when such workpieces are engaged by the projections of the respective clamping portions.

13. A tool as defined in claim 1, wherein the arm means of at least one of said clamping units comprise plural arms and distancing elements disposed between the arms of each arm means.

14. A tool as defined in claim 13, wherein said distancing elements constitute means for transmitting motion between said drive means and the arm means of said one clamping unit.

15. A tool as defined in claim 1, wherein said drive means includes a separate drive for the arm means of each of said clamping units.

16. A tool as defined in claim 1, wherein one arm means of at least one of said clamping units is adjustable with reference to the other arm means, and further comprising means for adjusting said one arm means.

17. A tool as defined in claim 16, wherein said drive means comprises a separate drive for each of said pairs of arm means and wherein said adjusting means is interposed between said one arm means of said one clamping unit and the respective drive.

18. A tool as defined in claim 1, wherein at least a portion of each of said arm means, including the respective clamping portion, is detachable from said carrier means to be replaced by a spare portion.

19. A tool as defined in claim 1, wherein at least said clamping portions of said arm means consist of magnetic material.

20. A tool as defined in claim 1, wherein said carrier means comprises a plurality of portions which are movable with reference to each other and wherein each portion of said carrier means supports at least one of said clamping units.

21. A tool as defined in claim 20, wherein said carrier means comprises two portions each of which supports a clamping unit and means for articulately connecting said portions of the carrier means to each other.

22. A tool as defined in claim 21, further comprising detent means for fixing the portions of said carrier means in predetermined angular positions with reference to each other.

23. A tool as defined in claim 20, wherein the portions of said carrier means are movable lengthwise of and are pivotable with reference to each other.

24. A tool as defined in claim 23, wherein the portions of said carrier means are coupled to each other by pinand-slot connections.

25. A tool as defined in claim 1, wherein said drive means comprises means for simultaneously moving the arm means of several clamping units with reference to each other.

26. A tool as defined in claim 25, wherein said carrier means comprises a rigid tubular carrier and said drive means comprises a spindle movably mounted in said carrier, a pair of cones mounted on said spindle and followers provided on the arm means of said clamping units and engaging with said cones to pivot the respective arm means in response to displacement of said spindle with reference to said carrier. A

27. A tool as defined in claim 1, wherein said drive means comprises at least one fluid-operated motor.

28. A tool as defined in claim 27, wherein said drive means comprises a discrete fluid-operated motor for each of said clamping units, each of said motors comprising a piston rod reciprocable at right angles to the respective pivot axis and a linkage connecting each piston rod with the respective arm means.

29. A tool as defined in claim 28, wherein said drive means further comprises shaft means for each of said clamping units, said shaft means being parallel to the respective pivot axes and being arranged to connect said linkages to the respective piston rods.

30. A tool as defined in claim 29, wherein each of said shaft means is disposed between the respective pivot axis and the clamping portions of the corresponding arm means.

References Cited UNITED STATES PATENTS 1,775,311 9/1930 Halle 2284 2,061,287 11/1936 Muehl 228-4 2,167,887 8/1939 Graham et a1. 269189X 2,800,867 7/1957 Smith 269-189 2,887,918 5/1959 Benson 269270X 3,422,519 1/ 1969 Fehlman 29200P THOMAS H. EAGER, Primary Examiner US. Cl. X.R.

ggs 4; 269-8, 189, 270