US2193888A - Method of producing seams in dandy rolls and apparatus therefor - Google Patents

Description

' March 19, 1940. P. s. s|NcLAlR METHOD OF PRODUCING SEAMS IN DANDY ROLLS AND APPARATUS THEREFOR 3 Sheets-Sheet 1 Filed Jan. 4, 1938 Y NN INVENTOR, 622/ S. Si/zclal);

ATTORNEY.

March 19, 1940. P, s SINCLNR' 2,193,888

METHOD OF PRODUCING SEAMS IN DANDY RQLLS AND APPARATUS THEREFOR Filed Jan 4, 1938 s Sheets-Sheet 2 INVENTOR,

ATTOFNEY.

P. s. SINCLAIR March 19, I940.

METHOD OF PRODUCING SEAMS IN DANDY ROLLS AND APPARATUS THEREFOR Filed Jan. 4, 1938 1 3 Sheets-Sheet 5 INVENTOR, filer J1 Ji/zchz ATTORNEY.

Patented Mar. 19, 1940 PATENT OFFICE METHOD OF PRODUCING SEAMS IN DANDY ROLLS AND APPARATUS THEREFOR Peter S. Sinclair, I-lolyoke, Mass.

Application January 4, 1938, Serial No. 183,312

. 7 14 Claims. This application is a continuation in part of an application filed on April 24, 1936, Serial Number 76,129. In the manufacture of dandy rolls and cylinder molds a woven wire fabric is placed on a suitable supporting structure of cylindrical form and its abutting edges are then joined together in a There are a number of disadvantages associated with this form of seam. In the first place 15 the individual wires of the wire fabric are usually very fine and the meshes very small so that a very considerable proportion of the total space is occupiedbythe wires and the openings or meshes in the wire fabric are not a very large proportion of the total space, sometimes less than half of the total space. Therefore when the wire used for sewing is passed back and forth through the meshes the total available space for drainage is greatly reduced and there is a tendency for the resulting paper to have marks thereon known as seam marking, a fault which is made more pronounced by whatever paper fibers are caught in the partially closed meshes thereby still further obstructing'proper drainage. Another disadvantage to be found in the sewed 4 seams of dandy rolls and cylinder molds when constructed in the usual manner is due to the fact that the strands of wire adjacent to the seam anddisposed parallel thereto aresometimes pulled out at the edge of the fabric by the strain exerted on them by the wire which interlaces from one side of the seam 'to the other. This tendency for the seam to pull out is somewhat reduced by increasing the number of strands back from the edge around which the interlacing takes place but inasmuch as this increases the width of the seam the total drainage obstruction is also increased and this in turn causes more of the objectionable seam marking. It therefore becomes necessary to compromise between the mechanical weakness of too few strands of wire interlaced by the sewing wire, particularly when there is only one strand on each side of the seam, and the ex-.

cessive seam marking when too many strands are interlaced. Two to five strands on each 'side of the seam have become common practice although not invariably followed. Themechanical weakness of this form of construction is especially objectionable because the wires do not all pull out 55 as soon as the clamps are released which are used for holding the fabric tight while it is being sewed but frequently at some later time when the dandy roll is in use, the unseasonableness of such an occurrence adding considerably to its undesirabllity. v 5 As a corollary to the mechanical weakness of sewed seams there is another disadvantage which flows therefrom in that it is not possible to place the woven wire fabric under the tension which would be desirable and which it would be capa- 1o .ble of withstanding if it were not for the weakness of the seam. With the relatively loose tension of the wire fabric the tendency isfor it to 1 work loose, while in'use, and in time to become injured with a total working life much less than 15 would be the case if it were placed on the dandy roll under a greater tension. The present invention relates to improvements in dandy rolls which are constructed with brazed or soldered seams instead of with the usual sewed 20 seams. Such soldered seams have been suggested heretofore but due to various difficulties encountered in producing them they have never gone into practical use. One difficulty has been the lack of strength with 'the ordinary soft solder 25 commonly employed. Another objectionable feature of soldered seams is due to the fact that the solder frequently runs into the meshes not only at the seam but for several meshes back away from the seam. Moreover the individual 30 wires in the woven wire fabric are so small that it is very easy to overheat them and greatly weaken them mechanically. This is particularly true when attempts are made to use a hard solder because of its greater strength since such a 35 solder requires a higher temperature. The term brazing is frequently applied to the operation of making a joint with hard solder and inasmuch as the present invention is perhaps even more adapted for use with such material than for use 40 with soft solder it is to be understood that the word solder as used throughout the specification and claims is intended to include brazing as well as soldering unless inconsistent with the context.

Stillanother difficultyin producing a sewed seam is encountered in connection with the belt used for tightening the wire fabric around the dandy roll and for drawing the edges of the seam close together or more specifically it is encountered when it becomes necessary to shift the belt along the dandy roll after one section has been soldered and in preparation. for soldering another section. The present standard prac tice of sewing the seam permits shifting of the belt quite readily as it is possible to loosen the last few loops of the sewing wire and permit the seam to widen in a taper, temporarily, while shifting the belt, whereby no one loop takes more than a part of the strain. On the other hand with a soldered seam each of the abutting wires which are soldered together constitutes a rigid connection which has no give whatsoever with the result that when the belt is shifted it would ordinarily be necessary for the last pair of abutting wires across the seam to sustain practically the entire tension of a considerable portion of the wire fabric near the seam and in general the last pair does take up the tension in that portion of the fabric which is still unsoldered. Under such strain the last pair of abutting wires will frequently break. This shifts the strain to the next pair of wires which may also break. In fact there is no definite limit where such breaking apart will stop.

It is one of the objects of the present invention to produce a satisfactory soldered seam in order to reduce or eliminate the disadvantages of sewed seams such as those hereinbefore enumerated, that is, the reduction of closed and clogged meshes of the wire fabric and the prevention of pulled out wires parallel to the seam.

It is also an object of the invention to improve the strength and wearing qualities of the seam by the increased tension and firmness with which the wire fabric is held is place.

It is another object of the invention to employ a hard solder and to provide means whereby the greater heat required for the fusion of this hard solder is localized at the ends of the wires which are soldered together and is prevented from overheating the wires back away from the seam. This accomplishes a two-fold secondary result. weakening of the individual wires because of overheating does not take place and the solder has a much less tendency to flow into the adjacent meshes and clog them up. a

More specifically it is an object of the inven tion to maintain the wire fabric at a relatively low temperature as close up to the seam as is possible while permitting the proper heat to be applied where the brazing or soldering takes place.

Still more specifically it is an object of the invention to provide a chill bar which is clamped against the wire fabric and extends close to the seam on both sides thereof whereby the heat is confined at the seam and is prevented from heating the wire fabric even a slight distance awa from the scam. I

More specifically still it is an object of the invention to use a chill bar of such a type and in such a manner that slight irregularities in the covering of the dandy roll will not prevent close contact with the wire fabric at all points. The specific form of chill bar disclosed herein for this purpose combines the substantial mass of metal required for its proper functioning with respect to the heat and at the same time a sufficient flexibility to follow the irregularities of the fabric along the seam and be capable of being pressed into contact with the fabric throughout its entire length.

It is also an object of the invention to provide a clamp for holding the adjacent unsoldered edges of the wire fabric close together near where the soldering has been completed so that the tightening belt may be shifted along to a new section of the dandy roll without danger of breaking the solderedconnections.

have In general it is an object of the invention to produce a soldered seam in a dandy roll by a new process as indicated above and to provide novel apparatus for carrying out such process.

The foregoing and other objects of the invention will readily appear to those skilled in the art to which it appertains by a consideration of the following description of one method of carrying out the invention taken in connection with the accompanying drawings in which there is shown suitable apparatus for carrying out such method and in which:

Fig. l is a top plan view of a portion of a dandy roll showing the usual apparatus employed for tightening the wire fabric preparatory to making a seam and also showing a chill bar and a seam clamp which are a part of the subject matter of the present invention;

Fig. 2 is a transverse section of the dandy roll taken on the line 2--2 of Fig. 1;

Fig. 3 is a fragmentary section taken on the line 33 of Fig. 2 and shows to an enlarged scale a portion of the chill bar and also a pressure slide in place thereon;

Fig. 4 is a section, to a still further enlarged scale, of the chill bar and pressure slide and is taken on the line 4-4 of Fig. 3;

Fig. 5 is a sectional view similar to Fig. 3 except that the chill bar has been removed and the clamping device is in position;

' Fig. 6 is a top plan view of the clamping device .and a portion of the woven wire fabric;

Fig. 7 is a sectional view, greatly enlarged, of the clamping device, taken on the line 1-4 of Fig. 5;

Fig. 8 is a perspective view of the base piece of the clamping device;

Fig. 9 is a perspective view of the clamping member of the clamping device;

Fig. 10 is a perspective view of the chill bar, cut transversely through one of the slots to show the form of the cross section;

Fig. 11 is a perspective view of the pressure slide used with the chill bar to hold it in close contact with the wire fabric of the dandy roll; and

Fig. 12 shows a somewhat different form of chill bar which may be used in place of the form shown in the other figures.

- Referring to the drawings more in detail the reference character ll indicates generally a supporting structure for a dandy roll or cylinder mold upon which is positioned a foundation woven wire fabric I2, sometimes called the backing fabric, which has its two abutting edges joined together in a seam l3. An upper or finish woven wire fabric l4, sometimes called the face fabric, which is positioned around the foundation fabric 2 is shown with its seam partly completed. That portion of the seam which is shown to the right in Fig. 1, indicated by the reference numeral l5, has been soldered while that portion of the fabric to the left of Fig. 1 is shown with the two edges spaced a slight distance apart, the upper edge being indicated by the numeral l6 and the lower edge by the numeral IT. The lower or foundation fabric is formed from somewhat larger wire and has somewhat larger meshes than the finish fabric but both fabrics seams and the problems and dimculties associated therewith are common to both fabrics. In the drawings the lower seam is shown as completed and the apparatus is shown in connection with the formation of the seam in the finish fabric but it is to be understood that bearing blocks 23 which may be moved toward 2,198,888 the same apparatus is also used in producing the scam in the foundation fabric.

The means employed for bringing the edges of the wire fabric closetogether and for maintaining .the fabric under a considerable tension comprises a pair of transverse members or supv which is heldv againstbeing moved, due to the tension of the belt, by a U-shaped member which may be positioned in any one of a plurality of notches in the support l8. The bearings for the ends of the roll 2| comprise a pair of slidable and away from the roll l9 by means of. a pair ofthreaded adjustable members 24 and. 25. A pair of arcuate guide rods 26 serves to maintain the proper relative positions of the two rolls l9 and 2| with respect to the supporting structure.

. Each guide rod 28 has its opposite ends positioned in apertures passing diametrically through the ends of the rolls I9 and 2| respectively. One

' end of the guide rod is secured in its aperture by a suitable set screw, as for example in the end of the roll I 9, while the other end is freely slidable in the aperture of the roll 2|. By tightening the members 24 and the wire fabric is drawn together at the edges l8 and I1. The belt 20 and associated apparatus so far described is old and the foregoing explanation is merely for the purpose of providing a background for the description of the rest of the apparatus.

Each of the transverse supporting members or supports i8 is provided with aclamp 21 which is adjustable along the support and, for reasons presently to appear, may be specifically designated as a chill bar clamp. A suitable wingheaded set screw 28 isprovided for securing the clamp in any adjusted position on the support l8. Each of the clamps 21 is provided with a projection or ear 29 which has a threaded aperture therein for a clamping screw 30. These clamping screws 30 rest against the two ends of a chill bar 3| and hold the bar in place against the wire fabric l4. The chill bar 3|, which is constructed of metal or material of high heat conductivity and capable of withstanding high temperaturea'has a longitudinal slot 32 therein and in operation the bar is sopositioned as to have the seam, about to be brazed or soldered, extend parallel to the slot and centrally thereof. The width of the slot is so chosen that the ends of the wires on both sides of the seam are exposed at the bottom of the slot and are also exposed back away from the ends for a slight distance. A more detailed description of the specificconstruction of this chill bar will be given later on but the foregoing outline is suflicient to indicate its cooperative functioning with the rest of the apparatus.

There is indicated in Fig. 1 a seam clamping device 33 and in Figs. 5, 6 and 7 the same clamping device is shown to a much larger scale. This clamping device comprises a base piece 34, a

clamping member 35, a pair of washers 38, and

which is generally rectangular in outline with the longer dimension in the direction of the seam, is provided with a pair of upwardly'extending threaded members 38 which are connected to the base piece by means of fins 33, the longer dimension of the fin also extending in the direction of the seam. These fins may be an integral part of both the base piece 34 and tliethreaded members 38 or for convenience in manufacture the fins may be sweated or welded into slots in the base piece and into similar slotsin the threaded members. The clamping member 35 is provided with a pair of circular openings into which the members 38 may be inserted and each opening 40 has outwardly extending slots 4| for the reception of the fins 39. The base piece 34 is preferably made in an arcuate form substantially equal to'the curvature of the dandy roll with which it is to be used. The clamping member 35 is preferably made in an arcuate form having a somewhat greater curvature than the base piece so that when the clamping member is clamped down against the base piece there will be a certain amount of resiliency in the clamping member to assist in its clamping action. It will be noted that each of the washers 36 is counterbored on the under side so as to provide an annular flange. This serves two functions. There is pro- .vided a clearance for the fins 39 and also the fiange is capable of a tighter clamping action than a flat surface. While the drawing shows the clamping nut 31 and the washer 36 as being separately fabricated, parts it is to be understood that they are preferably secured together as by soldering, brazing or welding and they may if desired be formed integrally out of a single piece of material.

The details of construction of the preferred form of chill bar can'be best seen in Figs. 4 and Ill. The slot 32 is .V-shaped, that is, it is narrower at the bottom and the walls of the slot slope back away from the bottom so that the width of the slot at the top is much wider thanat the bottom. This permits the flame which is used for soldering or brazing to reach to the very bot-. tom of the'slot and yet the wire ends are protected up to the very I or brazing is being done. at the bottom are vertical, not sloping, as indicated at '42, toavoid the weak and. unsatisfactory knife-edge outline which would result if the walls were sloping all the way to the bottom. The sloping walls of the slot also terminate in a'vertical portion 43 near their top so as to provide a guideway for a purpose presently to be explained. In order to give to the chill bar as a .whole a certain amount of flexibility there are place where the soldering The walls of the slot l are not in alinement with the slots in that portion of the'bar seen at the left in Fig. 10, and indicated by the reference character 45. actual use of such a chill bar seems to indicate that such a staggered relationship of the transverse slots on the two sides of the longitudinal slot is distinctively advantageous. While not necessarily limiting such advantages to those here enumerated there are at least two worthy The of mention. The primary purpose of the longitudinal slot being to shield the wires from the flame back away from the seam and to confine the flame to the seam it follows that any lateral spreading of the flame at one of the transverse slots would reduce the effectiveness of the scheme for concentrating 'the flame at the seam. Two transverse'slots in alinement would be twice as bad as one alone. The staggered spacing of the slots therefore tends heating of the seam as the flame is moved along the longitudinal slot. A second advantage is that the staggered spacing gives a chill bar that is not quite so fragile or likely to break unexpectedly.

The purpose of the transversely slotted chill bar is flexibility. Such a chill bar is capable of a certain amount of deformation whereby it can follow the irregularities of a dandy roll and lie close to the wire fabric throughout the whole length of the seam. Because of this very flexibility and also because of the fact that the flame is applied to only a short length of the seam at one time it is very desirable if not absolutely necessary that means be provided for producing and maintaining a close contact between the chill bar and the wire fabric near the point of application of the flame used for the soldering or brazing. Such means is provided in the form of a pressure slide, indicated generally by the reference character 46 and illustrated in more or less detail in Figs. 4 and 11. This comprises a flat horizontal portion 41 having vertical depending flanges 48 which embrace the sides of the chill bar as shown in Fig. 4. Beneath the flat portion 41, and parallel to the flanges ll, there extends a guide rib is having vertical side walls 50 which cooperate with the vertical walls 43 of the longitudinal slot}! as shown in Fig. 4. A knob SI of wood or other suitable heat insulating material is secured to the upper side of the pressure slide by any suitable means such as a screw 52. The pressure slide in operation serves two functions. By means of the pressure of the operator's hand on the knob ii the pressure slide is pushed down against the chill bar and because of the slotting of the chill bar and its resultant flexibility it is held close against thewire fabric ,even though the dandy roll is somewhat irregular so that otherwise the chill bar would not naturally lie close against the wire fabric throughout its entire length. A second function served by the pressure slide is the maintaining of the two sides of the chill bar in their proper spaced relation by virtue of the flanges 48 and the guide rib 48. It has also been found desirable to provide one or more cross connections or bridges I! at the bottom of the longitudinal slot to prevent the spreading of the two side members of the chill bar and the widening of the slot. Two such bridges are shown in the drawings but it is obvious that the exact number may be variedvto -meet different conditions. Such cross connections or bridges require that the chill bar be shifted longitudinally when making'the brazed connections under such bridges but this disadvantage is more than offset by the resulting advantages. While the precise method of providing these bridges is no part of the invention it might be stated that a small weld across the slot has been found to be very satisfactory.

It will be noted that the chill bar is undercut at both ends as indicated bythe reference character 54. This is for The end of the chill bar not being slotted, it has toward a more uniform.

, t0. the top two different purposes.

no flexibility at the ends. If therefore there happens to be a hump or slight protuberance just under one of .the chill bar clamps such hump does not necessarily raise the bar as a whole away from the fabric along its entire length. In other words it is only that portion of the chill bar which is flexible that is in contact with the wire fabric and such flexible portion is capable of adjusting itself to slight irregularities wherever there is such actual contact. Another advantage of the undercut feature is that the heads of a dandy roll usually project above the level of the wire fabric a small fraction of an inch and with the undercut ends it is possible to slip the chill bar over the heads and complete the soldering of the fabric through the longitudinal slot 32 up to the very end of thedandy roll.

In Fig. 12 is shown a chill bar Ila of somewhat simpler form than that shown in Fig. 10. In this case the transverse slots are omitted and since there is little or at least very much less use for the pressure slide no provision is made for it, the sloping walls of the slot extending clear without any vertical portions which are used in the form of Fig. 10 for a guideway.

Before the woven wire fabric is positioned around the supporting structure one of the edges, or both if so desired, is prepared with a suitable fusible material such as a hard silver solder. Such solder is designated generally in Fig. 4 by the reference character II. There are various ways in which solder may be applied to one of the edges and there are several patents covering special ways of performing this step in the process. Inasmuch as the novelty of the present invention resides in subsequent steps of the process any s'peciflc description ofsuch earlier steps has been omitted and it is taken for granted that such information is available and that at least one of the edges has been suitably prepared with solder.

To cover a dandy roll in accordance with the present invention'a piece of woven wire fabric is flrst cut out to the proper dimensions so that it will be just long enough to extend circumferentially around the dandy roll. One of the edges, or both, isthen prepared with solder as set forth in the preceding paragraph. The wire fabric is next positioned around the dandy roll and the adjacent edges drawn tight against each other by means of the belt 20. The chill bar ii is then positioned over the edges so that the proposed onto the ends of the chill bar to hold it flrmly in place. The juxtaposed edges are then heated by the flame from a suitable torch which is directed downward throughjthe slot 32. As the solder II is heated it is softened and unites the two edges in a strong soldered seam. As has been previously stated ordinary soft solder does not make a suitable seam or joint and therefore it ispreferable to' employ a hard silver solder. Such a solder requires a higher temperature than the ordinary soft solder and it is very easy to overheat the ends of the individual wires in the wire fabric or even for some distance back from the edge. By. the use of the' metallic chill bar 1i, which is of substantial size and heat storage capacity as compared with the fine wire fabric, the heating of the small wires in the fabric does not extend back from the seam for any substantial distance during, the short period of 16 time necessary for melting the solder and making the joint. This is due to several factors. The chill bar shields the fabric from the direct 'action of the flame except right at the seam.

Furthermore, due to the fact that it is a heavy mass of metal, the bar conducts the heat away from the wires where it comes in contact with them. The sloping walls of the slot are provided so that there may be a better utilization of both of these factors. be narrow at the scam in order that the heat may be confined to the fabric close to the seam. It is also necessary, in order to obtain the full value of the chill bar as a means for leading away the heat, that it shall not be too thin or else it will be heated itself almost as readily as the fabric. If these two requirements of a narrow slot and a thick chill bar, and consequently a deep slot, are met with a straight wall slot it is very difficult for a torch to maintain the proper temperature.

at the bottom of the slot. With the sloping walls, however, the slot is narrow at the bottom, there is abundant metal for cooling purposes, and the flame is able to reach the bottom of the slot and heat the seam properly.

A still further factor contributing to the protection of the ends of the warp 'wires except right at the seam is the complete exposure of the fabric to the cooling effect of the air on its under side, that is, the fabric is not cooled by some intermediate member which in turn radiates its heat to the air but the fabric, on its under side, is at all times exposed to the air and is thereby kept relatively cool.

As already briefly touched upon in the earlier part of this description the chill bar is maintained in close contact with the work and the width of the slot is maintained at just the right spacing by means of the pressure slide 46. In using this pressure slide the operator, if he is right handed, rests the palm of his left hand on the knob with the thumb on the wire fabric outside the chill bar on one side of the seam and with the fingers of the same hand'on the wire fabric outside the chill bar on the other side of the seam. If the edges of the fabric do not lie approximately as they should the pressure from the palm of the hand is relaxed and the thumb and fingers manipulate the edges of the fabric until the seam is lined up satisfactorily when the pressure of the palm of the left hand is restored, holding the chill bar and fabric in place while the right hand is used for applying the heat from the torch.

Another disadvantage frequently encountered in previous attempts to produce a soldered seam is also eliminated by the use of the chill bar. In order for the solder to run back away from the seam and fill the meshes of the fabric it is necessary that it remain hot enough to be fairly fluid and also the wires with which it comes into contact must be fairly hot. With the chill bar it is impossible for the heat to extend back away from the seam any farther than the edge of the chill bar or possibly not back quite so far as the edge of the chill bar because of the tendency of the latter to conduct away the heat. It will thus be seen that the foregoing device simultaneously takes care of two of the serious difficulties heretofore encountered in attempts to produce a soldered seam, namely, the wires do not have their strength impaired by the heat applied for soldering and the solder is prevented from running back away from the seam and filling up the meshes of the wire fabric.

It is clear that the slot should- After the seam has been completed as far along 'the length thereof as the slot in the chill bar permits, the clamping screws 30 are loosened and the chill bar 3| removed. The seam clamp is then put in position as shown in Fig. 5 as near to the completed portion of the seam as possible.

This is done by first inserting the base piece 34 under the wire fabric with the edges l6 and ll of the unsoldered fabric as close together as the I hold the edges 16 and I1 tight between the base piece 34 and the clamping member 35. As already'stated it is to be noted that the washer 36 is counterbored or recessed on its under side. This enables it to hold more firmly against the curved upper surface of the clamping member 35 than would be the case if it were only a flat washer. While the washer 36 and the nut 31 are shown as two separate members it is obvious that they may be made as one member if so desired. Because the curvature of the member 35 is slightly greater than that of the base piece 34, as already'mentioned, there is a certain amount of resiliency which helps to hold the parts tightly together. The belt 20 and associated apparatus can then be moved along the seam to a new position and the fabric drawn up the seam from tearing out during the shifting of the belt.

This tearing out of the soldered seam during the shifting of the belt and of the tightening apparatus is a trouble encountered in soldered seams in a way peculiar to them and not encountered in the sewed seams of the former practice. When a sewed seam is being made and it becomes necessary to shift the belt it is usual to loosen the last few stitches so that the unsoldered edges l6 and l! taper away from the completed seam the distance between the edges becoming gradually greater. The wire used for sewing joint since after the connection has been made it will, under tension, either break or take up the entire strain placed upon it since there is no flexibility or give to such a connection. Inasmuch as practically-all the tension for some little distance beyond the seam is placed upon the last piece of solder this readily torn apart. With this piece of solder torn apart the next piece'of solder is in turn subjected to the full strain so that'it is impossible to produce a soldered seam in sections with anything at all like proper tension at the joint unless some means is provided for sustaining the tension while the belt is being shifted from one position to another.-

While the foregoing description and accompanying drawings are believed to set forth the best way of practicing the invention it is to be understood that various changes may be made therein without departing from the spirit and scope of the invention as defined in the subjoined claims.

I claim:

1. Apparatus for producing a brazed or soldered seam in the woven wire covering of a dandy roll wherein said fabric is supported on a skeleton framework so as to leave substantially the said seam and heldtightly against said covering,

whereby said chill bar protects the wire covering on the outside from the direct action of a soldering flame and leaves the wire covering on the inside beneath the chill bar free to dissipate away the heat conducted to it from the heated seam.

2. The process of making a soldered or brazed seam in the woven wire covering of a dandy roll comprising tensioning said covering and bringing the edges thereof at the seam into juxtaposition, applying a flame to the edges of the covering and simultaneously protecting the covering from the direct action of the flame on the outside of said covering and on each side of said seam and also simultaneously dissipating away freely the heat of the wire covering inside the dandy roll both at the seam and back from the seam where it is protected from heat interchange on the outside.

3. A clamping device for holding in place the opposed edges of a woven wire fabric positioned around a dandy roll and maintained under tension comprising a base piece formed to substantially the same curvature as the dandy roll positioned within said roll, a clamping member of substantially the-same form as the base piece positioned outside of said roll, and means positioned between said opposed edges and extending directly from said base piece to said clamping member for drawing said clamping member toward said base piece and for holding said fabric tightly therebetween.

4. A clamping device for holding in place the opposed edges of a woven wire fabric positioned around a cylindrical supporting structure comprising a base piece positioned under said edges, a clamping member of substantially the same form as the base piece 'positioned above said edges, and means positioned between said edges extending from said base piece to said clamping member for drawing them tightly together and holding the edges of the fabric therebetween, the cross section of said means between the opposed edges being elongated with the longer dimension in the direction of the seam and the shorter dimension separating the opposed edges.

5. A clamping device for holding in place the opposed edges of a woven wire fabric positioned around a cylindrical supporting structure comprising a base piece positioned under said edges with one portion of said base piece extending under the fabric back away from one edge and another portion of said base piece extending under the fabric back away from the other edge, a pair of members extending upwardly from said base piece and having thin fin-like portions adjacent to the base piece positioned between the opposed edges of the fabric, a clamping member of substantially the same form as the base piece and having apertures through which the upwardly extending members and fins extend, and means for drawing said members and base piece upwardly and pressing said clamping member downwardly to clamp the edges of the fabric there between. i

6. A clamping device for holding in place the opposed edges of a woven wire covering positioned around a dandy roll comprising a thin base piece of substantially the same curvature as said dandy roll, threaded members extending upwardly from Said base piece and having fin-like portions adjacent thereto to permit the edges to lie close to each other, a thin clamping member positioned above said base piece and having apertures through which said threaded members extend and having slots extending radially from said apertures for the reception of said fin-like portions, and clamping nuts on said threaded members for drawing said clamping member against said base piece to hold the fabric tightly therebetween, said clamping member having a curvature slightly greater than said base piece to give a resilient clamping action as it is tightened in place.

7. The process of making a soldered or brazed seam in the woven wire covering of a dandy roll or cylinder mold comprising positioning a woven wire fabric having at least one of its edges suitably prepared with fusible material around a supporting structure with said edges'in opposed relationship, tightening the fabric around a portion of said supporting structure to bring the edges into contact with each other, clamping metallic chill means of substantial cross-section to said fabric close to each edge of the seam so as to leave a narrow slot above the edges and between ,the metal at each side thereof, applying heat to said edges to melt the fusible material and to unite the opposite edges, removing the metallic chill means, clamping the opposite unjoined edges by clamping means having upper and lower portions joined by thin fin-like members, shifting the tightening means to a new portion of the fabric, tightening the fabric as before, removing said clamping means, and repeating the foregoing steps until the entire length of the seam has been united.

8. Apparatus for use in producing a brazed or soldered seam in the woven wire covering of a dandy roll comprising tensioning means having a cloth belt extending around said roll from a position a short distance away from the seam at one side thereof to a position a short distance away from the seam at the other side thereof, the width of said belt corresponding approximately to the length of the portion of the seam for which the fabric is being tensioned, said tensioning means also having a pair of members extending transversely of saidseam one-at each end of said portion, means positioned along said seam with the respective ends thereof under said transverse members for protecting the woven wire close up to the seam from the direct action of the means used for heating the seam and for conducting heat away from that portion of the woven wire with which it is in contact, a clamp carried by each of said members and adjustable transversely of said seam, each of said clamps havingmeans for detachably holding said protecting means tightly against the woven wire covenng.

9. Apparatus for use in producing a brazed or soldered seam in the woven wire covering of a dandy roll comprising tensioning means having a cloth belt extending around said roll from a position a short distance away from the seam at one side thereof to a position a short distance away from the seam at the other side thereof, the width of said belt corresponding approximately to the length of the portion of the seam for which the fabric is being tensioned, said tensioning means also having a pair of members extending transversely of said seam one at each end of said portion, a chill bar comprising a single metallic member with a longitudinal slot therein positioned with its respective ends under said transverse members and the slot along said seam, a clamp carried by each of said transverse members and adjustable transversely of said of the seam has been united.

seam,'each of said clamps having a threaded member whereby the end of said threaded member may be screwed down against one of the ends of said chill bar to hold it tightly in place against the woven wire.

10. The process of making a soldered or brazed scam in the woven wire covering of a dandy roll or cylinder mold comprising positioning a woven wire fabric having at least one of its edges suitably prepared with fusible material around a supporting structure with said edges in opposed relationship, tightening the fabric by exerting circumferential tightening forces substantially uniformly throughout a longitudinal portion of the fabric except close to the seam whereby the edges are brought into contact with each other,

- applying heat to said edges-to melt the fusible material and to unite the opposite edges, clamping the opposite unjoined edges;nea r the finished portion of the seam by clamping means having upper and lower portions joined. by thin fln-like members, shifting the tightening means longitudinally of the fabric, tightening the fabric as before, removing said clamping means, and repeating the foregoing steps until the entire length 11. Apparatus for producing a brazed or soldered seem inthe woventwire covering of a dandy roll comprising an elongated chill bar having substantial thickness from the top to the bottom thereof and having a longitudinal slot midway of itssides extending from the top to the bottom thereof, the walls of said slot sloping outwardly 1 from near the bottom to near the top and having a short vertical portion near the top at each side,

a pressure slide having depending flanges embracing the outside of the chili bar and having a central rib-positioned between said short vertical side waiis'wherebythelateral spacingofthetwo against the woven ly and outwardly in a general sloping direction to provide a slot wider at the top than at the bottom, said bar having aplurality of a relatively large number of transverse slots in said members to provide flexibility in said bar, and a plurality of a relatively smaller number of bridges connecting said members at the bottom of the longitudinal slot to prevent lateral relative movement of said members and the consequent changing of the width of the slot.

13. A device of'the character described for use in making a brazed or solderedseam in the woven wire covering of a dandy roll comprising two elongated members disposed parallel to each other and separated by a longitudinal slot and adapted to be positioned on the woven wire covering with the slot above the seam, each of said members being flexible in a longitudinal direction so as to follow the irregular contour of the woven wire and also having a substantial heat storage capacity, said characteristics being attained by a construction in which the lower portion of each of said members is thin andhas a smooth unbroken surface for resting against said wire covering, and an upper portion of substantial heat.

storage capacity in the form of a plurality of elements separated by transverse slots.-

14. Apparatus for producing a brazed or soldered seam in the woven wire covering of a dandy roll comprising a pair of elongated members disposed parallel to each other and separated by a longitudinal slot and adapted to be positioned on'the woven wire covering with the slot above the seam, said members being formed so that the walls of said slot slopeioutwardly from near the bottom to near the top and have a short vertical portion near the top at each side, a pressure slide having depending flanges embracing the outside of said members and having a central rib positioned between said vertical side walls whereby the lateral spacing of said members may be maintained and whereby they may be pressed down rn'rna asmcnsm.

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