JP4926027B2 - Connection structure of horizontal frame material and vertical frame material in door frame - Google Patents

Description

The present invention relates to a connecting structure of a horizontal frame member and a vertical frame member in a door frame.

Conventionally, when assembling a four-sided frame-shaped door frame, the end of the vertical frame extending in the vertical direction and the end of the horizontal frame extending in the horizontal direction are brought into contact with each other and welded. However, in order to perform welding while abutting the end portions of the vertical frame and the horizontal frame, two people are required, one who holds the end portion while holding the abutting state between the end portions and the other who performs the welding operation. Moreover, in the work while pressing the ends of the vertical frame and the horizontal frame, the abutting position is likely to be shifted, and as a result, the finish accuracy of the door frame may be lowered.

FIG. 9A shows a butt portion of the frame members on the finding surface of the conventional door frame, and the other frame member has an R-shaped corner at the end of one frame member. Work is poor because it is necessary to abut the edge and weld it so as to block the R part on the surface side of the abutting part, and further to polish the obtained embossed part with a file to finish it flat. It was a thing.

In patent document 1, in the joining structure of the door frame which does not require welding in joining of a vertical frame and a horizontal frame, the protrusion piece which has a small hole is provided in the edge part of one frame material to join, and the other to join The frame member is provided with a slit so that the projecting piece is inserted and fitted into the joint portion, and a head having a cross-sectional diameter larger than the cross-sectional diameter of the nail shaft portion is provided in the small hole of the inserted projecting piece. A fixed nail having a portion, a contact portion between the outer peripheral portion of the head of the fixed nail and a frame material surface provided with a slit, a contact portion between the small hole portion of the protruding piece and the fixed nail, and the fixed nail There is disclosed a door frame structure that is bonded and fixed at three points, that is, an abutting portion between a portion near the tip of the frame and a frame material surface provided with a slit. Although this thing can solve the trouble resulting from welding work, since it is necessary to drive a fixed nail in the state which matched the position of frame materials correctly, it cannot necessarily be said that workability | operativity is good.

Further, in Patent Document 1, the joining end portions of the vertical frame and the horizontal frame are each cut at 45 degrees, and in the frame body in which the protruding pieces and the slits are fitted and joined at a right angle, the side faces of the frame material are cut at 45 degrees. Distortion correcting means is provided at the abutting portion of the surfaces. The distortion correcting means has a close-contact guide fitting attached to the inner wall side of one abutment surface, and the face-matching flat plate and the abutment surface are brought into close contact with each other by driving and inserting the face-matching flat plate into the close-contact guide fitting. The distortion of the butt face is corrected so that the faces can be matched. However, the use of a special member such as a distortion correcting means has a disadvantage that the number of parts and the work are increased.
Japanese Patent No. 3281933

An object of the present invention is to provide a horizontal frame material in a door frame, which can efficiently perform an assembly operation of a door frame composed of a frame material having a finding surface on which an inclined edge is formed without reducing the finishing accuracy. It is in providing the connection structure of a vertical frame material.

The technical means adopted by the present invention is a connecting structure of the horizontal frame material and the vertical frame material in the door frame, and the end portions in the length direction of the finding surfaces of the both frame materials are formed on the inclined edges. A projecting piece is formed at the lengthwise end of one of the frame members, and an insertion groove into which the projecting piece is inserted is formed in one of the other frame members. A fitting groove extending in the groove width direction of the insertion groove is formed on the base end side of the piece, and in the other frame member, an end edge of the insertion groove in the groove width direction is the fitting groove. A fitting portion to be fitted is formed, and the protruding piece inserted into the insertion groove moves in the groove width direction of the insertion groove, so that the fitting groove moves in the groove width direction of the insertion groove. In the fitted state between the fitting groove of the projecting piece inserted into the insertion groove and the end edge of the insertion groove, the one side can be fitted to the edge. The inclined edge of the finding surface of the frame member and the inclined edge of the finding surface of the other frame member are abutted flush with each other, and the back surfaces of the both inclined edges that are abutted are fixed by a fixing means. It is a connection structure. In one preferable aspect, the fixing means is welding, and is formed by welding the back surfaces of the two inclined edges that are abutted against each other. Further, the fixing means is not limited to welding, and a fixing plate is adhered to the back side of the both inclined edges (using a double-sided tape or an adhesive), or directly on the back side of the both inclined edges. The thing to which an adhesion | attachment means (for example, adhesive agent) is applied is illustrated.

In the connecting structure of the horizontal frame member and the vertical frame member in the door frame according to the present invention, the protrusion of one frame member is inserted into the insertion groove of the other frame member, and the inserted protrusion is inserted in the groove width direction of the insertion groove. The door frame can be temporarily assembled by a simple operation of sliding it to the right. And at the time of temporary assembly, since the flush | matching of the inclined edges of the finding surface of a frame material is completed, the matching operation | work of inclined edges can be performed easily and accurately.

At the time of temporary assembly, the surface side of the abutting part between the inclined edges is flush, so there is no need to weld to fill the gap as in the prior art, and welding is performed from the back side of the abutting part. The butt portion can be fixed only by performing. In addition, at the time of temporary assembly, the fitting groove of the projecting piece of one frame member and the end edge of the insertion groove of the other frame member are in a fitted state, so that the flushing between the inclined edges is maintained. Therefore, it is not necessary to press the flushing portion, and the welding operation is facilitated. Further, the finishing work on the surface side of the butt portion, which has been conventionally performed, is simplified or unnecessary, and the work efficiency is improved.

Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the door frame as a whole has a vertical rectangular shape, and is assembled from an upper frame 1, a lower frame 2, and left and right vertical frames 3 and 4. 2 is a cross-sectional view of an upper frame portion of the door frame shown in FIG. 1, and FIG. 3 is a cross-sectional view of a vertical frame portion of the door frame shown in FIG. As apparent from the finding surfaces in FIGS. 1, 2, and 3, in the door frame, the inclined edges at both ends in the length direction of the finding surface of the upper frame 1 and the left and right vertical frames 3 and 4 are seen. The state where the inclined edge at the upper end of the attached surface, the inclined edge at both ends in the length direction of the finding surface of the lower frame 2 and the inclined edge at the lower end of the finding surface of the left and right vertical frames 3 and 4 are flush with each other It has become. Hereinafter, the structure of the door frame will be described in detail.

The upper frame 1 is a long member that extends in the horizontal direction, and has a lower surface portion 10 that extends in the opening width direction of the opening portion, and both edges of the width direction (direction perpendicular to the length direction) of the lower surface portion 10. Formed by bending the upper ends of the first finding piece 11 and the second finding piece 12 extending in a rising shape in opposition to each other and the first finding piece 11 and the second finding piece 12 horizontally. The first bent piece 13 and the second bent piece 14 are provided. The lower surface portion 10 includes a first lower surface portion 100 and a second lower surface portion 101 having different heights in the width direction, and a step portion 102 is formed between the first lower surface 100 and the second lower surface 101. .

As shown in FIG. 1, the first finding piece 11 has a reverse trapezoidal shape when viewed from the front, the upper side is longer than the lower side, and both end edges in the length direction of the first finding piece 11 are 45 degrees. Inclined edges 11A and 11A that are extended from the bottom to the top at an angle are notched. Similarly, both end edges in the length direction of the second locating piece 12 are notched in the inclined edge 12A (see FIG. 4).

Protruding pieces 15 are formed at both longitudinal edges of the first lower surface portion 100. Similarly, projecting pieces 16 are formed at both end edges in the length direction of the second lower surface portion 101. The projecting piece 15 has a trapezoidal guide portion on the distal end side, and a fitting groove S extending in a direction perpendicular to the projecting direction of the projecting piece 15 is cut out at one end on the base end side. An expanding guide portion is formed on the opening side of the fitting groove S. The projecting piece 15 has the same plate thickness as that of the first lower surface portion 100, and extends horizontally from the end surface in the length direction of the first lower surface portion 100. Similarly, the projecting piece 16 has a trapezoidal guide portion on the distal end side, and a fitting groove S extending in a direction orthogonal to the projecting direction of the projecting piece 16 is cut out at one end on the base end side. Yes. An expanding guide portion is formed on the opening side of the fitting groove S. The projecting piece 16 has the same plate thickness as the second lower surface portion 101, and extends horizontally from the end surface in the length direction of the second lower surface portion 101. As shown in FIG. 4, in the projecting piece 15 and the projecting piece 16, the fitting groove S is formed on the same side.

Further, the configuration of the projecting piece 15 will be described in detail with reference to FIG. The protruding dimension of the protruding piece 15 shown in FIG. 8A is slightly larger than the protruding dimension of the protruding piece 15 shown in FIG. 2, but the basic configuration is the same. As shown in FIG. 8A, the projecting piece 15 includes side edges 150 and 151 extending perpendicularly to the edge 100 </ b> A of the lower surface portion 100, and an inclined edge 152 on the tip side of the side edges 150 and 151. 153 and a tip edge 154 extending in parallel with the edge 100A of the lower surface portion 100 between the tips of the inclined edges 152, 153. Further, on the base end side of the side edge 151, a fitting groove S extending in parallel with the end edge 100A of the lower surface portion 100 is formed. On the base end side of the side edge 151 on the side where the fitting groove S is formed, an inclined edge 155 is formed at the opening of the fitting groove S, and the opening of the fitting groove S is expanded. A guide portion is formed. By forming the inclined edge 155 at the opening of the fitting groove S, fitting of the member to the fitting groove S is facilitated. Regarding the shape of the projecting piece 16, the description relating to the projecting piece 15 can be used, and thus detailed description thereof is omitted.

The lower frame 2 has a shape similar to that of the upper frame 1 and is a long member extending in the horizontal direction. The upper surface portion 20 extends in the opening width direction of the opening portion, and the width of the upper surface portion 20. Direction (direction orthogonal to the length direction) first and second locating pieces 21, 22, first locating piece 21, and second locating piece 22 that are opposed to both end edges and extend in a hanging shape. The 1st bending piece 23 and the 2nd bending piece 24 which were bent horizontally from the lower end of each are provided. The upper surface portion 20 includes a first upper surface 200 and a second upper surface 201 having different heights in the width direction, and a stepped portion 202 is formed between the first upper surface 200 and the second upper surface 201.

As shown in FIG. 1, the first finding piece 21 has a trapezoidal shape, the upper side is shorter than the lower side, and both end edges in the length direction of the first finding piece 21 are at an angle of 45 degrees. Thus, a notch is formed in the inclined edge 21 </ b> A extending from the upper side to the lower side. Similarly, both end edges in the lengthwise direction of the second finding piece 22 are notched at the inclined edges (not shown).

Protruding pieces 25 are formed at both ends of the first upper surface portion 200 in the length direction. Similarly, projecting pieces 26 are formed at both ends in the length direction of the second upper surface portion 201. About the shape of the protrusions 25 and 26, since the description which concerns on the protrusion 15 can be used, detailed description is abbreviate | omitted.

The vertical frame 3 is a long member extending in the vertical direction, and includes a prospective piece 30 extending in the opening height direction of the opening, and both edges of the prospective piece 30 in the width direction (direction perpendicular to the length direction). First folding piece 31 and second folding piece 32 extending in a more opposing manner, and the first folding pieces formed by folding the extending ends of first and second fitting pieces 31 and 32, respectively. A piece 33 and a second bent piece 34 are provided. The expectation piece 30 includes a first expectation surface 300 and a second expectation surface 301, and a step portion 302 is formed between the first expectation surface 300 and the second expectation surface 301. Insertion grooves 35 and 36 for inserting the protruding pieces 15 and 16 are formed at the upper end portions of the first and second prospective surfaces 300 and 301, respectively. An insertion groove (not shown) for inserting the pieces 25 and 26 is formed.

As shown in FIG. 1, the first finding piece 31 has a shape obtained by rotating a trapezoid 90 degrees in a front view, the outer side being longer than the inner side, and the length direction of the first finding piece 31. Both end edges are notched and formed in an inclined edge 31A that extends inwardly from the inside to the outside at an angle of 45 degrees. Similarly, both end edges in the lengthwise direction of the second finding piece 32 are notched in the inclined edge 32A (see FIG. 4).

The basic configuration of the vertical frame 4 is the same as that of the vertical frame 3, and the vertical frame 4 is a long member extending in the vertical direction, and a prospective piece 40 extending in the opening height direction of the opening, Bending the extending ends of the first finding piece 41 and the second finding piece 42, and the first finding piece 41 and the second finding piece 42 extending in opposite directions from both edges in the width direction of the expectation piece 40 A first bent piece 43 and a second bent piece 44 (see FIG. 2). The expectation piece 40 includes a first expectation surface 400 and a second expectation surface 401, and a step 402 is formed between the first expectation surface 400 and the second expectation surface 401. An insertion groove (not shown) for inserting the projecting pieces 15 and 16 is formed at the upper end portion of the first prospecting surface 400 and the second expectation surface 401, and the lower end portion of the first expectation surface 400 and the second expectation surface 401. An insertion groove (not shown) for inserting the projecting pieces 25 and 26 is formed.

As shown in FIG. 1, the first finding piece 41 has a shape obtained by rotating the trapezoidal shape by 90 degrees in a front view, and the outer side is longer than the inner side, and the length of the first finding piece 41 is long. Both end edges in the direction are notched at an inclined edge 41A extending in an outwardly expanding manner from the inside to the outside at an angle of 45 degrees. Similarly, both end edges in the length direction of the second finding piece 42 are also formed by notching an inclined edge (not shown).

The fitting between the projecting pieces 15 and 16 formed on the upper frame 1 and the insertion grooves 35 and 36 formed on the vertical frame 3 will be described with reference to FIG. First, the projecting piece 15 projecting from the end surface 100A in the length direction of the first lower surface portion 100 of the lower surface portion 10 of the upper frame 1 is inserted into the insertion groove 35 formed in the first prospective surface 300 of the vertical frame 3. Insert until 100A and the first prospective surface 300 abut. Next, the upper frame 1 is formed on the proximal end side of the projecting piece 15 by sliding the upper frame 1 in the groove width direction (horizontal direction) of the insertion groove 35 in a state where the end surface 100A and the first prospective surface 300 are in contact with each other. The fitting groove S is fitted to one end edge (fitted part) 35A of the insertion groove 35 to be in a fitting state (see FIG. 8B). 1 to 3 and 6, the fitting groove S formed on the base end side of the projecting piece 15 and one end edge 35A of the insertion groove 35 are in a fitted state, that is, in this fitted state. The inclined edge 11A of the first finding piece 11 of the upper frame 1 and the inclined edge 31A of the first finding piece 31 of the vertical frame 3 are flush with each other. In the present embodiment, since the upper frame 1 is formed with the two projecting pieces 15, 16, the fitting between the projecting piece 15 and the insertion groove 35 and the fitting between the projecting piece 16 and the insertion groove 36 are actually performed. Are performed simultaneously. The fitting of the upper frame 1 and the vertical frame 4 and the fitting of the lower frame 2 and the vertical frames 3 and 4 are performed in the same procedure.

The first prospecting surface 300 of the vertical frame 3, the insertion grooves 35 and 36 formed in the upper end portion of the second prospective surface 301, the insertion groove (not shown) formed in the lower end portion, and the first of the vertical frame 4 The dimensions (groove width dimension and groove gap) of the insertion grooves (not shown) formed in the upper end portion and the lower end portion of the expectation surface 400 and the second expectation surface 401 are the corresponding projecting pieces 15, 16, 25, 26. Needless to say, the dimensions and shape are acceptable. In the illustrated embodiment, each of the projecting pieces 15, 16, 25, 26 extends horizontally, and the corresponding insertion groove is also formed horizontally on the expected surfaces 300, 301, 400, 401 of the vertical frames 3, 4. ing. In addition, one end side of the insertion groove may have an opening shape, and in that case, the width dimension of the protruding piece may be larger than the width dimension of the insertion groove. Moreover, in one aspect, the plate | board thickness of the upper frame 1, the lower frame 2, and the vertical frames 3 and 4 is 1.6 mm, and the clearance gap between the fitting grooves S is 1.7 mm-1.9 mm.

The assembly of the door frame composed of the upper frame 1, the lower frame 2 and the vertical frames 3 and 4 formed in this way will be described. As shown in FIGS. 4 and 5, the protrusion 15 protrudes from the end surface in the length direction of the first lower surface portion 100 of the upper frame 1, and protrudes from the end surface in the length direction of the second lower surface portion 101. The projecting piece 16 is inserted into the insertion groove 35 formed on the first expectation surface 300 of the vertical frame 3 and the insertion groove 36 formed on the second expectation surface 301, and each end face and the first expectation surface 300 and the second expectation surface 301. Insert them horizontally until they come into contact with each other. In the state of FIG. 5, the inclined edge 11 </ b> A of the finding piece 11 of the upper frame 1 and the inclined edge 31 </ b> A of the finding piece 31 of the vertical frame 3, and the inclined edge 12 </ b> A of the finding piece 12 of the upper frame 1 and the vertical frame 3 are seen. The inclined edge 32 </ b> A of the attaching piece 32 is displaced in the groove width direction of the insertion grooves 35 and 36.

Next, from the state of FIG. 5, the upper frame 1 is slid in the groove width direction (horizontal direction) of the insertion grooves 35 and 36, so that the fitting groove S formed on the proximal end side of the projecting pieces 15 and 16 is formed. It fits into one end edge of the insertion grooves 35 and 36, becomes a fitting state, and is temporarily assembled (FIG. 6). In one embodiment, the sliding movement distance of the fitting groove S is 3 mm to 5 mm, and the alignment of the finding surfaces can be adjusted when the frame members are assembled within the range of this distance.

In the temporarily assembled state shown in FIG. 6, the inclined edge 11A of the finding piece 11 of the upper frame 1 and the inclined edge 31A of the finding piece 31 of the vertical frame 3, the inclined edge 12A of the finding piece 12 of the upper frame 1 and the vertical frame. The inclined edges 32A of the three finding pieces 32 are abutted and matched so that the finding surfaces are flush with each other.

The position of the upper frame 1 where the protrusions 15 and 16 are formed, the positional relationship of the positions where the insertion grooves 35 and 36 are formed in the vertical frame 3, and the groove width dimension of the fitting groove S are the same as those of the upper frame 1. When the frame 3 is temporarily assembled, that is, the projecting pieces 15 and 16 inserted into the insertion grooves 35 and 36 slide, respectively, and the respective fitting grooves S are fitted with the edges of the insertion grooves 35 and 36. In this case, it is designed in advance so that the inclined edges 11A, 12A on the upper frame 1 side and the inclined edges 31A, 32A on the vertical frame 3 side are in proper matching positions (at least the surface side is flush). Yes. Therefore, at the time of temporary assembly, the flushing edges 11A and 12A of the upper frame 1 and the flushing edges 31A and 32A of the vertical frame 3 are already flushed. Moreover, since the respective fitting grooves S of the projecting pieces 15 and 16 are fitted with the end edges of the insertion grooves 35 and 36 during temporary assembly, the inclined edges 11A and 12A of the upper frame 1 and the vertical frame 3 are fitted. The in-line abutting state with the inclined edges 31A, 32A is maintained, and it is not necessary to hold down in order to maintain the abutting state. In the fitted state between the fitting groove S and the end edges of the insertion grooves 35 and 36, the frame material is made of steel or stainless steel and is hard and has a characteristic that springback occurs, so that a processing error occurs in the frame material. However, since some distortion occurs, the upper frame, the lower frame, and the vertical frame can be tightly fitted together without any gaps.

The inclined edge 11A of the first finding piece 11 of the upper frame 1 and the inclined edge 31A of the first finding piece 31 of the vertical frame 3, the inclined edge 12A of the second finding piece 12 of the upper frame 1 and the first Since the inclined edge 32A of the one-piece piece 32 is abutted in a flush state, it is not necessary to deposit welding on the surface side of the abutting portion, and the inclined edges are fixed to each other only by welding on the back surface side. Assembly is performed. As illustrated in FIG. 9B, the welding is performed on the back surface side of the inclined edges 11 </ b> A and 31 </ b> A that are abutted, that is, the back surface side of the first finding piece 11 and the first finding piece 31 of the vertical frame 3. Weld along the butt so as to straddle the side.

Regarding the assembly of the door frame, the connection between one end of the upper frame 1 and the vertical frame 3 has been described. However, the connection between the other end of the upper frame 1 and the vertical frame 4, The connection with the vertical frames 3 and 4 is the same. In the illustrated embodiment, when the door frame is temporarily assembled, the four corners of the door frame are each fitted at two locations, for a total of eight locations. At the time of temporary assembly, butted edges are more accurately matched, and the abutted state is stably maintained.

In the present invention, the temporary assembling operation of the door frame is performed by inserting the protruding piece of one frame member into the insertion groove of the other frame member, and sliding the inserted protruding piece in the groove width direction of the insertion groove. In addition, since the diagonal dimensions of the entire frame can be easily obtained, the temporary assembly work can be performed alone. Furthermore, in the illustrated embodiment, since the narrow guide portion is formed on the tip end side of the projecting piece, the operation of inserting the projecting piece into the insertion groove can be performed smoothly. In addition, by forming an expanding guide portion in the opening of the fitting groove on the base end side of the protruding piece, the fitting groove of the protruding piece inserted into the inserting groove and the end edge of the inserting groove can be fitted. It can be done smoothly. And at the time of temporary assembly, since the flushing between the inclined edges of the finding surface of the frame material has already been completed and the butted state is maintained, it is not necessary to suppress the butted state of the tilted edges. Also, the welding work after temporary assembly can be performed alone.

Although the embodiment of the present invention has been described with reference to FIG. 1, the connecting structure of the horizontal frame member and the vertical frame member according to the present invention is the length direction of the finding surface 11 of the upper frame 1 as shown in FIG. 1A. 11A and the left and right vertical frames 3 and 4, the upper end inclined surfaces 31 and 41, and the upper end inclined edges 31A and 41A are in a state of being flush with each other. The present invention is also applied to a door frame in which 21 is abutted in a state (so-called “surface drop”) positioned on the inside with respect to the finding surfaces 31 and 41 of the vertical frames 3 and 4.

The present invention can be used as a connection structure of a horizontal frame member and a vertical frame member in a door frame.

It is a schematic front view of the door frame of the embodiment of the present invention. It is a schematic front view of the door frame of other embodiment of this invention. It is sectional drawing of the upper frame part of the door frame shown in FIG. It is sectional drawing of the vertical frame part of the door frame shown in FIG. It is a perspective view which shows the state before inserting the edge part of an upper frame in the upper end part of a vertical frame. It is a perspective view which shows the state by which the protrusion of the upper frame was inserted in the insertion groove of the vertical frame from the state of FIG. FIG. 6 is a perspective view showing a state (fitted state) in which the upper frame is slid relative to the vertical frame and temporarily assembled from the state of FIG. 5. It is a figure explaining fitting with the projection piece formed in the upper frame, and the insertion groove formed in the vertical frame. (A) is an enlarged view of a protruding piece, (B) is a figure which shows the fitting state of the fitting groove of a protruding piece, and the to-be-fitted part of the edge of an insertion groove. (A) is a figure which shows the welding of the conventional butt | matching part, (B) is a figure which shows the welding of the butt | matching part which concerns on this invention.

Explanation of symbols

1 Upper frame 11 First finding piece 11A Inclined edge 12 Second finding piece 12A Inclined edge 2 Lower frame 21 First finding piece 21A Inclining edge 22 Second finding piece 3 Vertical frame 31 First finding piece 31A Inclined Edge 32 Second finding piece 32A Inclined edge 4 Vertical frame 41 First finding piece 41A Inclining edge 42 Second finding pieces 15, 16, 25, 26 Projection pieces 35, 36 Insertion groove S Fitting groove

Claims (2)

A connecting structure of a horizontal frame material and a vertical frame material in a door frame,
The lengthwise ends of the finding surfaces of the two frame members are formed as inclined edges,
A projecting piece is formed at the lengthwise end of one of the frame members,
An insertion groove into which the protruding piece is inserted is formed in any other frame member,
In the one frame member, a fitting groove extending in the groove width direction of the insertion groove is formed on the proximal end side of the projecting piece, and in the other frame member, the insertion groove in the groove width direction of the insertion groove is formed. An end edge forms a portion to be fitted into which the fitting groove is fitted, and the protrusion inserted into the insertion groove moves in the groove width direction of the insertion groove, thereby fitting the fitting groove. Can be fitted to the edge in the groove width direction of the insertion groove,
In the fitted state between the fitting groove of the protruding piece inserted into the insertion groove and the end edge of the insertion groove, the inclined edge of the finding surface of the one frame member and the finding of the other frame member A connecting structure in which the inclined edges of the surfaces are abutted flush with each other, and the back surfaces of the abutted both inclined edges are fixed by a fixing means. The connection structure according to claim 1, wherein the fixing means is welding, and the back surfaces of the two inclined edges that are abutted are welded.

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