Collet for clamping a tube

The present invention is directed to methods and devices for tensioning or clamps cylindrical workpieces directed and specific to methods and apparatuses for clamping and retaining of cylindrical workpieces during orbital or current welding.

Background of the Invention

A Orbital arc welding equipment is often used to weld pipes and pipework, which in fluid handling use and processing systems. reveal example US Pat. No. 5,136,134 by Benway et al and US Pat. No. 4,223,686 by Benway et al orbital welding devices for welding a pair of tubular Workpieces. The therein disclosed devices or devices are primarily Systems for welding tubes small diameter addressed in closely confined spaces. reveal the '134 and' 686 patents a tube clamping assembly or arrangement for receiving and holding and retaining of the tubes to weld the are while welding or -vorgängen. The Rohrspann- or tube clamping device disclosed therein is generally a scissors-like clamp, each tube between a held movable clamping arm and a stationary clamp arm at the location becomes. A pipe is fixed in each pair of arms so that they in the end-to-end abutting Relationship are present. Once the tubes have been secured, is Orbital welding head or arc welding head inserted into the pipe clamp assembly to the welding work perform, and the tubes are welded together at their abutting connection. The present invention is directed to improvements in or Rohrklemm- directed tensioning arrangement, the similar fact and in other Tube jigs disclosed.

If cylindrical workpieces be welded, have to the workpieces will be aligned radially and axially and so that the end of the first workpiece at the end of the second workpiece comes to bear. However, manufacturing tolerances limit the precision of a radial orientation, which in most tube clamping assemblies can be achieved. Accordingly, there is a need for a tube clamping device, the capable is accurate ensure radial alignment between the tubular workpieces. An additional Problem that often with existing scissors-type tube clamping devices occurs, that is, that the fixed clamping arms which typically integrally or are integrally formed with the base, are not removable. Accordingly, in when the fixed clamping arms are damaged, the entire definition be replaced. There is therefore a need for a tube clamping assembly, the removable clamp arms, especially removable stationary clamp arms owns.

Around proper alignment of the tubes to be welded, ensure an axial movement of the clamp arms should be minimized will. It has been found that the Clamping arms axially outwardly while bulging of jamming of the cylindrical workpieces trumpet shape or can be widened like a funnel. The reaction of the radial Clamping force on the outer diameter the tube can be transferred in an axial force component, which causes the clamp arms, a trumpet shape outward dilate. The outward movement , the pipes move so that their ends stop not longer are in contact. Furthermore, Wageningen de found that shrinkage of the weld joint while a welding can cause movement of the clamp arms inward. The movement inward may cause the arms to tweak in the welding or clamp which is held by the clamping arrangement, which the weld head rotor rotation may deteriorate or hinder. Accordingly, there is a requirement for an arrangement for limiting the axial movement of the clamp arms both in the axial direction inwardly and outwardly.

Finally, it should each set of clamping arms the workpieces with sufficient force such terminals to securely grip the workpiece therein to any Move during welding to avoid. For example, U.S. Patent 4,868,367 of Benway et al, such an apparatus for gripping and retaining a workpiece within a collar or ring. However, existing collars can not sufficient contact points between the collar and the pipe to disposal filters, which allows the tube is to shift the collar. Accordingly, a requirement for a tube clamping assembly which has a ring which is suitable Points of contact between the ring or sleeve and the tube ensures.

As an example refers <patcit><text>US-A-5,118,024</text></patcit> on a distant or remote control pipefitting tool for an adjustable Positioning the ends of relatively small pipes while adherent or spot-welded is, wherein the tool includes clamps and comprises the take adjacent pipe ends, each of the terminals laterally having extending arms, which at their outer ends by a plurality of spaced rotary buckle with a pair of outer rotary buckle and internal rotation buckles are connected, the various&lt;?page 3?&gt;ent relationships Set between the pipe ends.

It is the object of the present invention, a pipe clamp assembly to provide or tube jig is available, which is a improved alignment between two cylindrical workpieces which received therein, available provides.

This The aim is achieved by a pipe clamping device which the claim having 1 features disclosed. Preferred embodiments are Subject of the dependent Subclaims.

The present invention is a tube clamping assembly comprising a having adjustable base to a radial alignment of the welded to enable tubes, has removable / replaceable side panels, provides an arrangement for a Limiting an axial movement of the clamping arms are available and has a collar or ring that sufficient points of contact between the Ring or the sleeve and the workpiece to disposal provides. More specifically, the present invention provides a split or split basis, which a first portion and a second portion, wherein the first portion adjustable relative to the second portion is to select an appropriate radial alignment of the pipes to be welded ensure. Using the adjustable features of the present invention can achieve precise alignment of the workpieces will. The invention includes a tube clamping assembly comprising a first portion having a base and a clamping device, which is supported on the base, and a second portion, the having a base and a clamping device which on the basis of is worn. The first and second section are connected such coupled to the Parts or sections may be adjusted relative to each other.

The present invention comprises or includes stationary Clamping arms which at the base can be fixed removable, which makes it allows them is for repair or replacement to be removed. In this way can they, when the component is damaged, to be repaired, instead that entire unit must be replaced. In this configuration, the invention provides a tube clamping assembly comprising a base and a first movable clamp arm and a first stationary clamping arm, coupled to the base for gripping a cylindrical workpiece between. The Rohrklemm- or tube jig further comprises a second, movable clamping arm and a second stationary clamp arm, coupled to the base for gripping a cylindrical workpiece therebetween, wherein at least one of the stationary clamping arms or clamping arms is removably coupled to the base.

The present invention also uses an arrangement of overlapping and interlocked, arcuate signs to an axial movement to prevent the clamp arms in both axial directions. These inventive arrangement minimizes cramping or terminals of the welding head while welding or -vorgängen and also ensures that the workpieces remain in an abutment relationship to ensure good and clean welds. In this embodiment, the invention is a pipe clamping arrangement or The tube clamping assembly comprising a base, a first clamping device, which is supported on the base, a second clamping device, which is supported on the base, and locking means for limiting an outward directed axial movement of the first and second pair of clamping devices.

Finally used the present invention provides a ring of a polygonal, preferably hexagonal has form when it is in the gripping position. These Ring or collar assembly provides a minimum of contact points on the tube outer diameter to disposal, when the tube in its minimum, nominal or maximum Tolerance state. These contact points increase significantly establishing support stiffness, thus minimizing the chance for the tube, to move after it has been clamped. In this embodiment, includes the invention provides a ring or a sleeve for clamping a cylindrical Workpiece, wherein the collar comprises a pair of clamp parts each having a clamping surface, which is adapted to opposite Sides of the workpiece take, each clamping surface generally than half a Polygon is formed in the side view, the polygon having at least six sides.

Numerous other embodiments of the invention are or will be described and claimed herein and other features and advantages of the present Invention will be apparent from the following detailed description Reference to the accompanying drawings and claims will be apparent, which form a part of the specification.

DESCRIPTION OF THE DRAWINGS

<figref idrefs="S25">1</figref> is a perspective view of the tube clamping assembly or tube jig of present invention, which is shown in the gripping position;

<figref idrefs="S26">2</figref> is an exploded perspective&lt;?page 4?&gt;illustration of the lineup clamp from <figref idrefs="S25">1</figref>;

<figref idrefs="S27">3</figref> is a plan view of the tube clamping assembly of <figref idrefs="S25">1</figref>. shown set with a pair of tubes therein;

<figref idrefs="S27">4</figref> is a front view of the tube clamping assembly of <figref idrefs="S25">1</figref>. shown set with a pair of tubes therein;

<figref idrefs="S28">5</figref> is a side view of the tube clamping assembly of <figref idrefs="S25">1</figref>. shown set with a pair of tubes therein;

<figref idrefs="S28">6</figref> is a detail cross-section along line 6-6 of <figref idrefs="S28">5</figref>;

<figref idrefs="S29">7</figref> is a front view of a tube and the tube clamping assembly of <figref idrefs="S25">1</figref>. in the release or release position is shown;

<figref idrefs="S29">8</figref> is a front view of the tube and the tube clamping assembly of <figref idrefs="S29">7</figref> With one of the movable clamp arms in the gripping position;

<figref idrefs="S30">9</figref> is a front view of the tube clamping assembly of <figref idrefs="S25">1</figref>. which is shown with a pipe and an orbital or orbital welding head is;

<figref idrefs="S31">10</figref> is a detailed front view of a tube and the tube clamping assembly from <figref idrefs="S25">1</figref>;

<figref idrefs="S31">11</figref> is a front view of an alternative embodiment of the tube clamping assembly the present invention; and

<figref idrefs="S32">12</figref> is a detailed front view showing the arrangement of the hexagonal tube clamping surfaces.

Detailed description

As this best in <figref idrefs="S25">1</figref> and <figref idrefs="S26">2</figref> shown is, has the lineup clamp <figref>10</figref> according to the present Invention provides a set of clamp arms <figref>12</figref>. <figref>14</figref>. <figref>16</figref>. <figref>18</figref> to the Clamping a pair of cylindrical workpieces, such as pipes <figref>20</figref>. <figref>22</figref>. therein to the pipes at their adjacent abutting or adjacent connection <figref>24</figref> (<figref idrefs="S28">5</figref>) To weld. The welded joint is at the abutting each other Point <figref>24</figref> the tubes are formed. The tube clamping assembly<figref>10</figref> includes or includes a base <figref>30</figref>Which generally rectangular in a plan view, and includes an opening <figref>31</figref>Therein is formed to a orbital or orbital welding head <figref>33</figref> (<figref idrefs="S30">9</figref>) take. The base<figref>30</figref> should have a solid construction be to the pipe clamp <figref>10</figref> to impart stability. A pair of first clamp arms <figref>12</figref>. <figref>14</figref> is at a Side of the base <figref>30</figref> arranged and a pair of second clamp arms <figref>16</figref>. <figref>18</figref> is on an opposite side the base <figref>30</figref> arranged. The first stationary clamp arm<figref>14</figref> is generally rigid at the base <figref>30</figref> set and the first movable arm <figref>12</figref> is pivotally hinged to the base, so he is a flathead screw <figref>32</figref> can rotate. In a similar way is the second stationary clamping arm <figref>18</figref> generally rigid at the base <figref>30</figref> established or fixed, and the second movable clamp arm <figref>16</figref> is pivotally connected at the base <figref>30</figref> set such that it is a flathead screw <figref>34</figref> (<figref idrefs="S27">3</figref>) can rotate. Each pair of clamping arms forming together a releasable clamping device<figref>26</figref>. <figref>28</figref>, It should be understood that a size Plurality of clamping devices exist, which are used may include, without departing from the scope of the present invention, and such may obligations Klemmvorrich include any apparatus which clamp a cylindrical workpiece and solve can.

Each said clamp arms <figref>12</figref>. <figref>14</figref>. <figref>16</figref>. <figref>18</figref> Has a clamping surface or clamping surface <figref>36</figref>. which in the embodiment illustrated, a section is formed in the clamp arms. The clamping surface<figref>36</figref> can than a semicircle, a half-ellipse or half a hexagon or other regular or irregular shapes be formed. The first movable clamp arm<figref>12</figref> pivotally a cross or gripping position (<figref idrefs="S29">8</figref>), in which the clamping surface <figref>36</figref> of first movable clamp arm <figref>12</figref> with the clamping surface <figref>36</figref> of first stationary clamping arm <figref>14</figref> is oriented to a tube <figref>20</figref> between to take. The first movable clamp arm<figref>12</figref> is also to be a release or release position (<figref idrefs="S29">7</figref>) Movable so that the tube <figref>20</figref> not by the clamping surfaces <figref>36</figref> moved is. It should be understood that the release position is any position, in which the pipe can be removed from the clamping device, and the movable clamp arm need not to the in <figref idrefs="S29">7</figref> moved position illustrated are to be in the release position to rule. All that is required is that the clamp arms their grip to a sufficient degree addressed in order to make it possible that this Tube is removed or inserted, which by axial movement are running the tube can. Accordingly, the position of the first movable illustrated clamping arm <figref>12</figref> in <figref idrefs="S29">7</figref> the fully open position, and in this condition is also the clamping arm in the release position. Similarly, the second movable Klammarm <figref>16</figref> in between a gripping position and a Lösposition movable. In both<figref idrefs="S29">7</figref> and <figref idrefs="S29">8</figref> is the movable clamping arm <figref>16</figref> in the fully open Position.

Each Clamping arm can machined cuts or cut-outs or slits <figref>38</figref> exhibit, disposed adjacent to the clamping surfaces <figref>36</figref> scheduled are to the clamping surfaces flexibility &lt;?page 5?&gt;to give when they resiliently or elastically grip the circumference of the pipes. This training and the resilient nature the clamping surface is the subject of US Pat. No. 4,868,367 and US Patent no. 4,973,823.

Each the movable clamp arms <figref>12</figref>. <figref>16</figref> is operated independently or movable by separate actuating means <figref>40</figref>. <figref>42</figref>. which move the associated arm between the gripping and release positions. In the present embodiment, the actuating means <figref>40</figref>. <figref>42</figref> Cam actuating assemblies. The structure and operation of the first movable clamp arm <figref>12</figref> becomes described below, although the movement of the second movable clamping arm <figref>16</figref> is substantially identical. The cam actuator assembly<figref>40</figref> includes or includes a cam plate <figref>44</figref> (<figref idrefs="S26">2</figref>. <figref idrefs="S29">8</figref>), Which a pivotal movement about a make-up or shoulder screw <figref>47</figref> movable is. The cam plate<figref>44</figref> between the base <figref>30</figref> and the movable clamping arm <figref>12</figref> locked in. The movable clamping arm <figref>12</figref> beinhaltert an approximately L-shaped opening <figref>46</figref>, A shoulder screw<figref>47</figref> becomes through the opening <figref>46</figref> passed and is in the base <figref>30</figref> picked up by a thread. The shoulder screw <figref>47</figref> helps the movable arm <figref>12</figref> at restrain the base and leads the pivoting action of the movable arm <figref>12</figref>, A cam pin or -stift<figref>48</figref> on the cam plate <figref>44</figref> extending through to the outside the L-shaped opening <figref>46</figref>,

The cam plate <figref>44</figref> also has a outwardly extending flange <figref>50</figref>, If desired is, the movable clamping arm <figref>12</figref> to the release position move, the flange is <figref>50</figref> downward or clockwise pressed, as in <figref idrefs="S29">8</figref> is shown, which causes that the cam plate <figref>44</figref> around the shoulder screw <figref>47</figref> rotates. If and as the cam plate <figref>44</figref> rotate, engages the cam pin <figref>48</figref> the clamping arm <figref>12</figref> at the edge of the L-shaped opening <figref>46</figref>whereby He clamping arm the <figref>12</figref> applied to the release position. On further rotation of the cam plate moves the movable clamping arm <figref>12</figref> to the full open position, as shown in <figref idrefs="S29">7</figref> shown is. can in the release position to be welded pipe <figref>20</figref> between the clamping arms <figref>12</figref>. <figref>14</figref> arranged be or the straight welded pipes can of the clamping arms are removed.

Around to move the movable clamp arm to the gripping position, are the flange <figref>50</figref> and the cam plate <figref>44</figref> in the Counterclockwise direction moves, as in <figref idrefs="S29">7</figref> shown is and the cam plate <figref>44</figref> take a-bringing into engagement surface <figref>51</figref> in the clamping arm <figref>12</figref> (<figref idrefs="S29">8</figref>). These activity forcing or urging the clamp arm <figref>12</figref> to the gripping position. If in the gripping position (<figref idrefs="S29">8</figref>) Take the clamping surfaces <figref>36</figref> said clamp arms <figref>12</figref>. <figref>14</figref> opposed Sides of the tube <figref>20</figref>To securely hold it in place. The activity the movable clamping arm and the cam plate and its associated components is described in detail in US Pat. No. 5,136,134.

As this best in <figref idrefs="S26">2</figref> is shown, the Base <figref>30</figref> a first portion <figref>52</figref> and a second section <figref>54</figref>, have the first and the second section respective sections <figref>31</figref>, The cuttings <figref>31</figref> so directed out to close or exactly one orbital welding head in take. The first and second portions relative to each other movable to enable settings of the pipe clamp. A relative adjustment in two directions (two directions in is the plane of one of the clamp arms) with the present invention used to provide a precise radial Alignment of the tubes allow. A pair of hex or Allen screws <figref>56</figref>. <figref>58</figref> becomes through a pair of holes <figref>60</figref> of first section <figref>52</figref> passed and is threadably or screwed into the second section <figref>54</figref> added. As this in <figref idrefs="S28">6</figref> As shown, the holes are <figref>60</figref> greater than the outer diameter the screws <figref>56</figref>. <figref>58</figref>So that when the screws are loosened, the first paragraph <figref>52</figref> and the second section <figref>54</figref> relative are each movable. Once the first and second portions their desired Relative positions are arranged, the hexagonal screws tightened to as the first <figref>52</figref> and the second section <figref>54</figref> relative immobilize each other and define, as in <figref idrefs="S28">6</figref> illustrated is. Once the screws are tightened, the first and the second section <figref>54</figref> pressed against each other so that friction forces relative motion prevent.

As this in <figref idrefs="S28">5</figref> As shown, the first portion <figref>52</figref> a Notch or undercut <figref>62</figref> and the second section <figref>54</figref> Has a groove <figref>64</figref>Which closely notch <figref>62</figref> receives. The notch and groove arrangement is accommodated in such a way that the gap <figref>68</figref> in between the first portion and the second portion not through the Abstützpfosten or -steher <figref>66</figref> out must become. In this way, the gap <figref>68</figref> between the first portion and the second portion side, and for ease of manufacture Use postponed. However, if desired, the gap <figref>68</figref> down to the center of the base <figref>30</figref> carried be, and this can for example be desirable if the start-up or Abstützsteher are not used.

in the Generally, it is desired, the first <figref>52</figref> and the second section <figref>54</figref> so align, that a tube <figref>20</figref>. by the first movable clamp arm <figref>12</figref> and the first stationary clamping arm <figref>14</figref> is maintained, generally coaxial with a tube <figref>22</figref>&lt;?page 6?&gt;aligned is that by the second movable clamp arm <figref>16</figref> and the second stationary clamping arm <figref>18</figref> is held. To accomplish this, can a tube within each clamping device <figref>26</figref>. <figref>28</figref> established be and the hex bolts <figref>56</figref>. <figref>58</figref> so dissolved be that the first and second portions can be adjusted to align the tubes. However, is a preferred method for achieving alignment, first dissolve the hex bolts and then a single tube through both sets pass out of clamp arms. The arms are then down on the tube by shifting the clamped movable arms to the gripping position, whereby the first Set of arms and the second set arms to "align themselves". The hexagon bolts<figref>56</figref>. <figref>58</figref> can then are attracted downwardly to the first and second section relative to each other to immobilize and the single tube may are then removed. Assuming that the tube is straight and even, is or the first set of clamp arms is now the second Set of clamp arms aligned. This alignment can after a Manufacture or before distribution of the clamp assemblies <figref>10</figref> of the carried out the present invention be, or may also be performed in the field or on-site, if the Klemman Regulation should subsequently require realignment.

Of the first stationary clamping arm <figref>14</figref> generally rigid at the base <figref>30</figref> established and the first movable clamp arm <figref>12</figref> is at the base <figref>30</figref> pivotally determined that he is a flathead or Versenkschraube <figref>32</figref> turn can. Similarly Way is the second stationary clamping arm <figref>18</figref> generally rigid at the base <figref>30</figref> established and the second movable clamp arm <figref>16</figref> is pivotally attached to the Base <figref>30</figref> so articulated that it is the shoulder screw <figref>34</figref> turn can. Flathead screws<figref>32</figref>. <figref>34</figref> are by Wellenbeilagscheibe <figref>72</figref> (<figref idrefs="S26">2</figref>. <figref idrefs="S27">3</figref>) guided and securing the first set of arms <figref>12</figref>. <figref>14</figref> and the second set of arms <figref>16</figref>. <figref>18</figref> respectively on the Base. A shoulder screw<figref>70</figref> holds each stationary clamp arm <figref>14</figref>. <figref>18</figref> at the base <figref>30</figref> articulated and stationary clamping arms can be removed are to be repaired, to be serviced or replaced. To the first stationary clamping arm <figref>14</figref> remove the flathead screw will <figref>32</figref> and shoulder screw <figref>70</figref> away. The shoulder screw<figref>47</figref>. the first movable arm <figref>12</figref> connects with the base or coupled, must also be removed. Once the screws<figref>32</figref>. <figref>47</figref>. <figref>70</figref> away are able both the first stationary and the first movable clamp arm to be removed from the base. The same procedure can be carried out are to the second clamp arms <figref>16</figref>. <figref>18</figref> to remove. In this way, when any of the clamping arms is faulty, damaged or otherwise must be repaired or replaced, removed and / or replaced will. The Erstatzteil is through the shoulder screws and the Flathead screws in the same manner as the original Part, described above, determined.

As this in <figref idrefs="S31">10</figref> is shown, which form the clamping surfaces or ranges <figref>36</figref> the clamping arms, or more generally clamp parts <figref>12</figref>. <figref>14</figref>. <figref>16</figref>. <figref>18</figref> preferably generally a hexagon when the movable clamp arm <figref>12</figref>. <figref>16</figref> in the gripping position. Thus, the clamping surface<figref>36</figref> of each clamping arm commonly referred to as half a hexagon or the hexagon formed and the clamping arms are preferably symmetrically. In this way, changes in pipe size<figref>20</figref> by the clamp assembly are taken up or compensated and numerous Contact points are ensured. When the pipe to be taken is relatively large, bend the slots <figref>38</figref> sufficient to eight contact points between the gripping surfaces <figref>36</figref> and the tube <figref>20</figref> to enable. In the present embodiment, there are eight contact points <figref>67</figref>. <figref>69</figref>. <figref>71</figref>. <figref>73</figref>. <figref>75</figref>. <figref>77</figref>. <figref>79</figref>. <figref>81</figref> around the circumference of the pipe <figref>20</figref>, However, the arms may constructed be that the slots <figref>38</figref> in a position other than in <figref idrefs="S31">10</figref> shown, are arranged. The slots may be arranged such that it do not cut any of the contact points. In this case, the contact points <figref>67</figref>. <figref>69</figref> in a single point of contact combined, as the contact points <figref>75</figref>. <figref>77</figref> are. So there is in an alternative embodiment, only six contact points between the tube and the generally hexagonal shaped gripping surfaces <figref>36</figref>, If no slots are present at any of the contact points, should the arms be flexible enough to expect six points of contact for the largest Pipe available deliver. That is, the workpiece, to be taken, normally is a tolerance range in relation to its outer diameter own and the arms should be flexible enough through the slots and be other means to the widest possible pipe within to accept the tolerance range and still provide a minimum to provide six contact points available.

Other Shapes of the clamping surfaces are also possible, preferably other polygonal shapes forming. For example can generally have a triangular, square, pentagonal or pentagonal or polygonal shape, regular or irregular, by the closed clamping arms are formed. However, forms in a preferred embodiment, each side of the polygon an obtuse Angle to the adjacent pages. In a further preferred Forming the connection between adjacent sides of the Polygons <figref>76</figref> curved surfaces or areas to the reluctance of inert gases over the weld joint during welding work to support.

&lt;?page 7?&gt;

Each half the hexagon is preferably at an offset from the center cut of the tubular workpiece, to be gripped within the ring. For example, under reference the <figref idrefs="S32">12</figref> the center of a cylindrical workpiece at the point A represented. The center of the half hexagon of the clamping area of ​​the clamping arm <figref>12</figref> is shown as point B and the center of the half hexagon of the clamping surface the clamping arm <figref>14</figref> is shown as point C. The remaining Contour of each hexagon for each clamping surface is represented by dashed lines. In the illustrated embodiment, the center of each hexagon in a direction away from the corresponding Clamp arm offset with respect to the center of the workpiece A. In the<figref idrefs="S32">12</figref> illustrated or illustrated dimensions are greatly exaggerated for the purpose of illustration and the centers of each hexagon are to an appropriate dimension for the required use such as 0.25 mm (0.01 inch) offset in a training. The displacement of the center of each Hexagon allows it the clamp arms to grab a tube which has a relatively having small diameter. When they moved to the gripping position be able the hexagons of each clamp arm "overlap" as in <figref idrefs="S32">12</figref> is shown to grip a tube that has an outer diameter at the lower End of the tolerance range has, and at least six points of contact are guaranteed.

Furthermore, Preferably, the length from each side of the hexagon has a length equal to the diameter Largest pipe, from which is intended that there with the clamping device can be used; ie the largest pipe diameter in the Tolerance for the workpieces. As This was discussed earlier, can Clamping surfaces, commonly referred to as regular polygons are shaped to be used. In this case, the length of a Side of the polygon is preferably about equal to the diameter of the largest pipe in the tolerance range.

The clamping surfaces <figref>36</figref> can in a collar or ring to be formed, and the clamping arms can be adapted are to accommodate different rings or sleeves therein. The Rings can be exchanged be with rings, the clamping surfaces of have different shapes or sizes. In this way, the clamping surfaces of the present invention be adapted to pipes of different record sizes or can changed are to be adapted to different welding conditions. It should be understood that the clamping surfaces and rings which are described above, in each type of composition or assembly can be used which is used to cylindrical workpieces jamming. For example, an arrangement or assembly for Gripping tubes wherein the clamp arms are generally parallel to the base <figref>30</figref> in contrast are perpendicular to the base, the clamping surfaces the present invention (<figref idrefs="S31">11</figref>use). In this configuration, the movable clamping arm <figref>12</figref> at stationary clamping arm <figref>14</figref> be fixed or mounted.

As this best in <figref idrefs="S25">1</figref> to <figref idrefs="S27">3</figref> shown is, includes the pipe clamp assembly <figref>10</figref> also a set of arcuate or arc signs <figref>80</figref>. <figref>82</figref> at the distal ends the clamping arms. Arcuate Signs help in shielding the welding arc from the eyes of the operator. However, the arc signs also as locking means for limiting the relative axial movement of the clamp arms in both serve in the direction axially directed axially inwardly than outwardly. A movement in the direction axially inward is here as axial movement of the clamping arms to the welded joint or the stop point <figref>24</figref> the pipes defined, and directional movement in the axially outward Direction than axial movement away from the weld <figref>24</figref> defined.

Of the second movable clamping arm <figref>16</figref> has a bracket <figref>84</figref>. which is disposed at its distal end. The clamp or the carrier <figref>84</figref> extends axially inward, he movable the gap between the second Clamp arm and the first movable clamp arm bridged. The clip<figref>84</figref> Has a downwardly extending flange <figref>86</figref>. formed or molded to tight the first movable clamp arm <figref>12</figref> at its axially outwardly take-facing side. In this way couples the bracket<figref>84</figref> the movable clamping arms to each other, thereby preventing any axial outward directed movement of the movable clamp arms relative one another. The first movable clamp arm has a cutaway portion <figref>87</figref>. around the flange portion <figref>86</figref> take, the path or cut-out portion <figref>87</figref> on the axially outward Side of the first movable clamp arm <figref>12</figref> is arranged. In this way, it is the flange <figref>86</figref> allows within the cut-away portion <figref>87</figref> during a closing and opening of a movable clamping arm to slide.

Of the first stationary clamping arm <figref>14</figref> has a spacer plate <figref>88</figref>Attached to is arranged its distal end. The spacer plate<figref>88</figref> extends axially inwardly, wherein the gap between the first stationary clamp arm <figref>14</figref> and the second stationary clamping arm <figref>18</figref> bridged. The plate <figref>88</figref> has a cutout <figref>90</figref>Who formed it is, which is shaped to a notch <figref>92</figref> on the second stationary clamping arm <figref>18</figref> take. In this way, the plate acts<figref>88</figref> as a spacer and is si&lt;?page 8?&gt;cher, that the stationary clamping arms remain spaced apart by a certain distance. The spacer plate <figref>88</figref> thus blocks any axially inward directed movement of the stationary Poor.

It can be seen therefore that, when the coupling assembly is in the gripping position, the movable clamp arms with each other through the bracket <figref>84</figref> so are coupled to the clamp arms <figref>12</figref>. <figref>16</figref> at one Expanding outwardly to block, and the spacer plate <figref>88</figref> blocks the stationary clamp arms from shifting axially inwardly. As shown in<figref idrefs="S25">1</figref> and <figref idrefs="S27">3</figref> be seen is, are the stationary Clamp arm and the movable clamp arm in each pair of arms overlapping arranged. The movable clamp arms<figref>12</figref>. <figref>16</figref> are axially outside from the respective clamp arms <figref>14</figref>. <figref>18</figref> arranged. This overlapping / herself miteinan the locking assembly is an axial movement of all blocking clamp arms in both axial directions or prevented. The movable clamp arms are axially outward from the stationary clamp arms arranged and thus block the stationary clamp arms on a ride up or sliding outward. The stationary Clamp arms are located axially within the movable clamp arms and block over the spacer plate <figref>88</figref> the movable clamp arms on a Moving axially inwardly. The clamping arms can, as far as desired, overlapping be arranged to ensure that the arms do not from a Position slide relative to each other.

It it should be understood that the Arrangement of interlocking locked arc signs <figref>80</figref>. <figref>82</figref>. as discussed above, may be reversed. That is, the Arrangement of the spacer <figref>88</figref> may be on the second stationary clamp arm, and bracket <figref>84</figref> can be connected to the first movable clamp arm to be ordered. Furthermore, the spacer can at one of the movable clamp arms be located, and the clip can on one of the stationary clamp arms to be ordered. In yet another embodiment, the stationary clamp arms also coupled by a bracket and a flange, at an axial movement outward to prevent. In this embodiment, each movable clamping arm to the corresponding stationary Clamp arm by a tongue and groove arrangement coupled. The tongue and groove arrangement thus helps in limiting the axial movement of the clamp arms in both axial directions.

The preferred form of the present invention has been described above. However, with the present disclosure in mind, thought that obvious amendments gen to the preferred embodiments, to comparable features and advantages reach to those skilled in the art will be apparent.