GB2175321A - Sewing machine for sewing laminar block - Google Patents

Abstract

An industrial sewing machine comprises: a needle driving mechanism for a needle which has a recess 130 capable of engaging and disengaging a thread to a side wall at a lower end thereof; a thread winding mechanism for winding a thread by one turn around a portion of the needle protruded from the member 169 to be stitched when the needle is moved downwardly so that the lower end thereof penetrates through the member; a moving mechanism for moving the member to be stitched by a predetermined distance perpendicular to the needle when the lower end of the needle rises above the member while engaging the thread in the recess; and a rotational mechanism for rotating the needle to face the recess downstream with respect to the moving direction of the member before the lower end of the needle reaches the upper surface of the member during rising of the needle, and for rotating the needle to face the recess upstream while the lower end of the needle is situated above the member. <IMAGE>

Description

1 GB 2 175 321 A 1

SPECIFICATION

Laminar block and method of producing same This invention concerns a laminar block having a plurality of integrally laminated sheet-like members each of which is made of inorganic fibers and to a method of producing such a laminar block.

Laminar blocks each comprising a plurality of integrally laminated sheet-like members, each of which is made of inorganic fibers are employed, for instance, as linings to the wall part of the main body of a kiln of furnace for use in ceramic industry for heat-insulating or warm-keeping purpose.

One example of conventional laminar blocks used forthe lining of the furnace wall is shown in Figure 1 of the accompanying drawings. A laminar block 1 in Figure 1 comprises blankets 2, 2,.... each of which is made of inorganic fibers. In the laminar block 1 illustrated in the figure, thirteen sheets of rectangular blankets 2 are laminated. A laminar body 4 composed of the thirteen laminated rectangular blankets 2 are integrated to form the block 1 by a single thread 5, which is inserted into the laminar body 4 of the thirteen blankets 2 and bound at the both ends thereof so as to constitute a closed loop 3.

Upon using the laminar block 1 forthe lining on the wall portion of the furnace main body, it is disposed and secured within the furnace main body such that a face of the laminar block 1 at which the laminated portion is exposed, or the side face 6 is in contact with the inner surface of the wall portion of the furnace main body.

In the production of the laminar block 1, the size of the block 1 or the size of the blanket 2 is often specified to a certain standard size in view of the productivity or the like. When the laminar block is used for the lining on the wall of furnaces with different sizes or shapes, the laminar block 1 is cut into an optimum shape at the working place of applying the lining corresponding to the shape and the size of the applied portion.

However, when the laminar block 1 illustrated in Figure 1 is cut, for instancer into two sub-blocks 8 and 9 along the plane shown by an imaginary line 7 110 in Figure 1, the loop 3 of the thread 5 is cut or disconnected at two points 10 and 11 leaving each of the sub-blocks 8 and 9 in a state where the thread part 12 or 13 is merely inserted therein. Accordingly, the laminated blanket portions 2a and 2b of the laminar sub-blocks 8,9 can no more be kept integral.

For the integral lamination of blankets made of inorganic fibers, it has also been known to apply adhesives between blankets laminated with each other and securing the blankets to each otherto form 120 a laminar block.

In the laminar block in which laminated blankets are fixed with each other by means of the adhesives, however, each blanket constituting the laminar block is likely to be separated because each blanket is made of a stack of inorganic fibers.

Moreover, in the case of using inorganic adhesives, for example, in order to provide the laminar block with a sufficient heat-resistance, there is a difficulty in cutting the laminar block dueto the high rigidity of the solidified adhesive layer.

Furthermore, in the case where the inorganic adhesives are used between the blankets, there is fear that the adhesives may be firmly sintered with the fibers of the upper and lower blankets upon actual furnace operation, whereby intra-layer peeling may some time be resulted within the blanket in parallel with the plane of adhesion depending on the shrinkage of the fibers.

In addition, upon using the adhesives between the blankets to be laminated, it is actually impossible to move the laminar body until the applied adhesives between the blankets are cured, as well as the intralayer peeling have often been caused to the blankets when external forces are applied during so-called handling work such as transportation of the laminar block even after the adhesives have been cured.

This invention has been made in view of the foregoings in order to reduce at least a part of the disadvantages of the conventional laminar block.

According to a first aspect of this invention, there is provided a heatinsulating laminar block for lining an inner wall of a furnace, said laminar block comprising:

(a) a laminar body composed of a plurality of laminated sheet-like members, each of said plurality of laminated sheet-like members being made of inorganic fibers, said laminar block being applied to the innerwall of the furnace such that planes of the sheet-like members are generally perpendicularto the inner wall of the furnace, and (b) an integrating means for integrating said plurality of laminated sheet-like members with each other in compressed states in a laminated direction thereof to form the laminar block, said integrating means comprising a single line of stitches extending along a longitudinal direction of the sheet-like member at a central portion in a width direction of the sheet like member, the single line of stitches comprising a multiplicity of individual stitches made by at least one thread, each one of said multiplicity of individual stitches comprising:

(i) a first surface thread part extending along the outer surface of a first sheet-like member of said plurality of laminated sheet-like members which is situated at one surface side of said laminar body, said first surface thread part having a first end and a second end; 00 a first penetrating thread part extending substantially continuously from said second end of said first surface thread part through laminar body in the direction of the thickness thereof from said outer surface of said first one of said plurality of sheet-like members to the outer surface of a second one of said plurality of sheet-like members which is situated at the opposite surface side of said laminar body, said first penetrating thread part having a first end connected to said second end of said first surface thread part and a second end; 0ii) a second surface thread part extending substantially continuously from said second end of said first penetrating thread part along said outer surface of said second one of said plurality of laminated sheet-like members, said second surface thread part 2 GB 2 175 321 A 2 having a first end connected to said second end of said first penetrating thread part and a second end; and (iv) a second penetrating thread part extendin substantially continuously from said second end of said second surface thread part through said laminar body in the direction of the thickness thereof from said outer surface of said second one of said plurality of sheet-like members to said outer surface of said first one of said plurality of sheet-like members, said second penetrating thread part hav ing a first end connected to said second end of said second surface thread part and a second end, said second end of said second penetrating thread part of each one of said multiplicity of individual stitches being connected to a first end of a first surface thread part of an adjacent one of said multiplicity of individual stitches, whereby, even when the laminar block is cut into sub-blocks across the single line of stitches, said integrating means enables the adjacent laminated sheet-like members of each of said sub blocks to remain integrated with each other in the compressed states.

This aspect of the invention also provides a heat-insulating laminar blockfor lining an innerwall 90 of a furnace, said laminar block comprising:

(a) a laminar body composed of a plurality of laminated sheet-like members, each of said plurality of laminated sheet-like members being made of inorganic fibers, said laminar block being applied to the innerwall of thefurnace such that planes of the sheet-like members are generally perpendicular to the inner wall of the furnace, and (b) an integrating means for integrating said plurality of laminated sheet-like members with each other in compressed states in a laminated direction thereof to form the laminar block, said integrating means comprising a plurality of lines of stitches distributed over the plane of the sheet-like member, each line of said plurality of lines of stitches comprising a multiplicity of individual stitches made by at least one thread, each one of said multiplicity of individual stitches comprising:

(i) a first surface thread part extending along the outer surface of a first sheet-like member of said plurality of laminated sheet-like members which is situated at one surface side of said laminar body, said first surface thread part having a first end and a second end; (H) a first penetrating thread part extending sub stantially continuously from said second end of said first surface thread part through laminar body in the direction of thethickness thereof from said outer surface of said first one of said plurality of sheet-like members to the outer surface of a second one of said plurality of sheet-like members which is situated at the opposite surface side of said laminar body, said first penetrating thread part having a first end connected to said second end of said first surface thread part and a second end; (iii) a second surface thread part extending sub stantially continuously from said second end of said first penetrating thread part along said outer surface of said second one of said plurality of laminated sheet-like members, said second surface thread part having a first end connected to said second end of said first penetrating thread part and a second end; (iv) a second penetrating thread part extending substantially continuously from said second end of said second surface thread part through said laminar body in the direction of the thickness thereof from said outer surface of said second one of said plurality of sheet-like membersto said outer surface of said first one of said plurality of sheet-like members, said second penetrating thread part having a first end connected to said second end of said second surface thread part and a second end; and (v) said second end of said second penetrating thread part of each one of said multiplicity of individual stitches being connected to a first end of a first surface thread part of an adjacent one of said multiplicity of individual stitches, whereby, even when the laminar block is cut into sub-blocks, said integrating means enables the adjacent laminated sheet-like members of each of said sub-blocks to remain integrated with each other in the compressed states.

A second aspect of the invention provides a method of producing a heatinsulating laminar block of a plurality of sheet-like members for lining an inner wall of a furnace such that planes of the sheet-like members are generally perpendicular to the inner wall of the furnace, said method comprising the step of sewing a laminar body composed of the plurality of laminated sheetAike members made of inorganic fibers to each other so as to integrate said plurality of laminated sheet-like members with each other in compressed states in a laminated direction thereof to form the laminar block by means of a single line of stitches extending along a longitudinal direction of the sheet-like member at a central portion in a width direction of the sheet-like member, the single line of stitches comprising a multiplicity of individual stitches made by at least one thread, each one of said multiplicity of individual stitches comprising:

(a) a first surface thread part extending along the outer surface of a first sheet-like member of said plurality of laminated sheet-like members which is situated at one surface side of said laminar body, said first surface thread part having a first end and a second end, (b) a first penetrating thread part extending substantially continuously from said second end of said first surface thread part through laminar body in the direction of the thickness thereof from said outer surface of said first one of said plurality of sheet-like members to the outer surface of a second one of said plurality of sheet-like members which is situated at the opposite surface side of said laminar body, said first penetrating thread part having a first end connected said second end of said first surface thread part and a second end; (c) a second surface thread part extending sub- stantially continuously from said second end of said first penetrating thread part along said outer surface of said second one of said plurality of laminated sheet-like members, said second surface thread part having a first end connected to said second end of said first penetrating thread part and a second end; GB 2 175 321 A 3 (d) a second penetrating thread part extending substantially continuously from said second end of said second surface thread part through said laminar body in the direction of the thickness thereof from said outer surface of said second one of said plurality of sheet-like members to said outer surface of said first one of said plurality of sheet-like members, said second penetrating thread part hav ing a first end connected to said second end of said second surface thread part and a second end; (e) said second end of said second penetrating thread part of each one of said multiplicity of individual stitches being connected to a first end of a first surface thread part of an adjacent one of said multiplicity of individual stitches, whereby, even when the laminar block is cut into sub-blocks across the single line of stitches, the single line of stitches enables the adjacent laminated sheet-like members of each of said sub-blocks to remain integrated with each other in the compressed states.

This aspect of the invention provides a method of producing a heat-insulating laminar block of a plurality of sheet-like members for lining an inner wall of a furnace such that planes of the sheet-like members are generally perpendicular to the inner wall of the furnace, said method comprising the step of sewing a laminar body composed of the plurality of laminated sheet-like members made of inorganic fibers to each other so as to integrate said plurality of laminated sheet-like members with each other in compressed states in a laminated direction thereof to form the laminar block by means of a plurality of lines of stitches distributed over the plane of the sheet-like member, each line of said plurality of lines of stitches comprising a multiplicity of individual stitches made by at least one thread, each one of said multiplicity of individual stitches coml5rising:

(a) a first surface thread part extending along the outer surface of a first sheet-like member of said plurality of laminated sheet-like members which is situated at one surface side of said laminar body, said first surface thread part having a first end and a second end; (b) a first penetrating thread part extending sub stantially continuously from said second end of said 110 first surface thread part through laminar body in the direction of the thickness thereof from said outer surface of said first one of said plurality of sheet-like members to the outer surface of a second one of said plurality of sheet-like members which is situated at the opposite surface side of said laminar body, said first penetrating thread part having a first end connected to said second end of said first surface thread part and a second end; (c) a second surface thread part extending sub stantially continuously from said second end of said first penetrating thread part along said outer surface of said second one of said plurality of laminated sheet-like members, said second surface thread part having a first end connected to said second end of said first penetrating thread part and a second end; (d) a second penetrating thread part extending substantially continuously from said second end of said second surface thread part through said laminar body in the direction of the thickness thereof from 130 said outer surface of said second one of said plurality of sheet-like members to said outer surface of said first one of said plurality of sheet-like members, said second penetrating thread part hav- ing a first end connected to said second end of said second surface thread part and a second end; (e) said second end of said second penetrating thread part of each one of said multiplicity of individual stitches being connected to a first end of a first surface thread part of an adjacent one of said multiplicity of individual stitches, whereby, even when the laminar block is cut into sub- blocks, said plurality of lines of stitches enables the adjacent laminated sheet-like members of each of said sub- blocks to remain integrated with each other in the compressed states.

In the block according to this invention, if the first stitching thread part is disconnected at the first surface thread part, the integrated state of the cut piece is maintained at least by the second stitching thread part.

In this specification, the term "laminar body" refers to a body produced by laminating or stacking a plurality of the sheet-like members made of the inorganic sheet-like members in which laminated or stacked sheet-like members are not integrated with each other, and the term "laminar block" refers to an integrated laminar body in which the laminated or stacked sheet-like members are substantially inte- g rated to fo rm a u n it.

In a preferred embodiment of this invention, a plurality of lines each of which includes the plurality of the first and the second stitching thread parts formed by the continuous thread are provided so that relatively small cut pieces produced by cutting the laminar block into various shapes may be kept integrated. Each of the plurality of lines may be composed of different threads respectively.

In one preferred embodiment of this invention, the first stitching thread part and the second stitching thread part belonging to at least one line is formed by a single chain stitch of a thread.

In an other preferred embodiment of this invention, the first and the second stitching thread parts belonging to at least one line is formed by a wave-like stitch of one thread (in this specification the "wave-like stitch" is referred to as a kind of stitch explained later in connection with Figure 5).

In a still other preferred embodiment of this invention, the plurality of the first stitching thread parts and the second stitching thread parts belonging to at least one line comprise two continuous threads crossing to each other to be bound with each other so as to withstand the tensile force, and the first and the second stitching thread parts are formed by the lock stitch of two threads.

At least one of the first stitching thread parts may be adapted to form an independent closed loop from other stitching thread parts, and at least one of the second stitching thread parts may also be adapted to form an independent closed loop from other stitching thread parts. The closed loop may be formed by binding of adjacent thread parts, or by securing of adjacent thread parts by adhesives.

The inorganic fiber constituting the sheet-like 4 GB 2 175 321 A 4 memberfor use in a [aminar block according to this invention comprise one or more among a crystal lized fiber made of a material such as mul[ite and alumina, a ceramic fiber made of a material such as alumino silicate a rockwool and a glass fiber and the like. The fiber may be composed of a plurality of fine twisted fibers. The diameter, the length and the cross sectional shape of the inorganiGfiber may optionally be selected depending on the kind of the sheet-like member and application use of the lami nar block.

The sheet-like member for use in the laminar block according to this invention may be a blanket, felt and/or bulkfiber assembly.

The density, the thickness, the standard shape or size for each of the sheet-like members, as well as the number of sheet-like materials constituting one laminar block may optionally be selected depending on the application use.

The sewing or stitching thread used in the laminar block according to this invention may be those threads made of natural organic materials such as linen and cotton, those threads made of synthetic organic material such as synthetic rubber, rayon, acetate and nylon, those threads made of synthetic or artificial inorganic fibers such as ceramic fibers, glass fibers and carbon fibers, as well as those threads made of metallic material such as nickel, chromium and stainless steel and a twisted strands made of ceramic fibers or glass fibers, which may be used solely or in admixture of two or more of them so long as the sewing thread can serve to maintain the laminar block orthe cut portion thereof in an integrated state until the block or the cut portion thereof is set or disposed to a desired position of an apparatus or the like such as a furnace.

The number of stitches per unit length or the stitch number per inch, that is, the number of the surface thread parts of the first and/orthe second stitching thread parts per unit length in each of the lines in the case where there are at least one line comprising a plurality of the first stitching thread parts and the second stitching thread parts, as well as the number of stitches per unit surface area, that is, the number of the surface thread parts of the first and/or the second stitching thread parts per unit surface area of the sheet-like member at a side of the laminar block in the case where there are at least one line comprising a plurality of the first and the second stitching thread parts can optionally be selected depending on the kind and the material of the sheet-like members to be laminated, the density and the thickness of the laminar body or the laminar block, the material and the diameter of the stitching thread, as well as the diameter of the stitching 120 needle that can be used.

Specifically, in the case where the laminar block is properly cut into pieces, for instance, better integrity between each of the laminated sheet-like members in the produced piece or sub-block can be obtained as the number of the stitches is increased. However, if the number of the stitches is excessively increased, the strength of the laminar block may rather be reduced due to the increase of the hole area in the block left after the passing of the sewing needle, and 130 the thread may be slackened due to the joining of adjacent stitches or short-cut of the stitching thread.

Furthermore, since the sheet-like member, e.g., a blanket made of fibers has a considerable hardness due to the nature of the constituent inorganic fibers, a considerable mechanical resistance is resulted upon insertion of a stitching needle and a thread although the blanket is fiberous. Then, the needle and the thread have to be suitably tough and rigid and in a considerable diameter in order to withstand such a machanical resistance. Thus, it is not so advantageous to increase the number of stitches excessively.

Accordingly, the practical length for each of the stitches (corresponding to the feeding amount or length of the sewing machine), that is, the length for each of the first and/or second surface thread parts is usually in a range between 10 - 1 00mm.

In addition, the length for the surface thread part of the first stitching thread part and that of the second stitching thread part may be equal to or different from each other, or the length of the surface thread part of the first or the second stitching thread part may be or may not be uniform.

The laminar block according to this invention, is applicable not only to the heat-insulating orwarmkeeping wall such as the lining of the furnace wall but it is also applicable to other application uses such as sound insulation walls, cold insulation walls and cushions for use at a high temperature.

This invention is to be described in more details referring to the accompanying drawings, by which the foregoing and other features of this invention will be made clearer and in which:

Figure 1 is an explanatory perspective view of a conventional laminar block; Figure 2 is an explanatory perspective view of a laminar block as a preferred embodiment according to this invention; Figure 3 is an explanatory view showing one example of the details of a thread for constituting the laminar block shown in Figure 2; Figure 4 is an explanatory view showing another example of the details of a thread for constituting the laminar block shown in Figure 2; Figure 5 is an explanatory perspective view of a laminar block as another embodiment according to this invention; Figure 6 is an explanatory perspective view show- ing an example where the laminar blocks shown in Figure 2 are applied to the lining of a furnace wall; Figure 7(a) through Figure 7(h) are explanatory views showing the steps of a production process of the laminar block shown in Figure 3; Figure 8 is an explanatory front elevational view of an industrial sewing machine; Figure 9 is an explanatory sectional view along a line X-X showing a part of the sewing machine in Figure 8; Figure 10 is an enlarged explanatory view of a part near the stitching needle of the sewing machine shown in Figure 8; and Figure 1 1(a) through Figure 1 1(r) are explanatory views showing the steps of a sewing process using the sewing machine shown in Figure 8.

GB 2 175 321 A 5 In Figure 2, a laminar block 20 as a preferred embodiment according to this invention is shown schematically.

The laminar block 20 comprises a plurality of rectangular blankets 21 as a sheet-like member, for instance, ceramic fiber blankets. A laminar body 22 consisting of ten blankets 21 laminated or stacked to each other is integrated by means of three lines of stitching or sewing threads 23,24 and 25 made of vinylon (Kuraray Vinymo 4). In the laminar block 20, the laminar body 22 may be or may not be compressed in its thickness direction (laminating direction). The structure of the stitching thread will be described in detail only with reference to the stitching thread 23 since the structure of the stitching threads 23, 24 and 25 is identical with each other.

The stitching thread 23 comprises a front side thread part 28 extended substantially continuously along the outer surface 27 of a blanket 26 situated on one surface side of the laminar body 22, a rear side thread part 31 extended substantially continuously along the outer surface 30 of a blanket 29 situated on the other surface side of the laminar block 22, and penetrating thread parts 44,45,46,47,48 and 48a which are respectively connected at their one ends 32,33,34f 35,36 and 37 integrally with the front side thread part 28, and at their other ends 38, 39,40, 41, 42 and 43 integrally with the rear side thread part 31, and extended substantially continuously between both of the ends thereof so as to penetrate the inside of the laminar body 22.

Each of "the thread parts which are extended substantially continuously" may be a single thread part extended continuously or two or more thread parts extended continuously while being placed in parallel or twisted with each other. Furthermore, the thread part may comprise two or more relatively short thread parts which are firmly bound or connected to each other at their longitudinal end so as to constitute a long thread part as the whole capable of withstanding the tensile force.

The "integral connection" may be carried out by binding the thread parts, fusing the thread parts, and/or bonding these parts by means of adhesives.

The thread 23 itself may comprise one or more threads.

In the laminar block 22, since the thread 23 forms five closed loops 49, 50, 51, 52 and 53, the laminar block 20 can be more homogenous as a whole than a type of conventional laminar block formed by the use of adhesive layers. Moreover, in a case if the block 20 is cut by means of a hand saw or the like along a line like the phantom line 7 shown in Figure 1 to disconnect, for instance, one of the loops 50, 51, 52, each of the two cut block pieces can be retained at least by one closed loop formed by a part of the thread 23 thereby preventing the blankets of the cut block pieces from being disintegrated individually. In the explanation above, for instance, the closed loop 49 comprises a surface thread part 28a between the integral connection parts 32 and 33 in the front side thread part 28,two penetrating thread parts 44 and 45 and a surface thread part 31 c between the integral connection parts 38 and 39 in the rear side thread part 31. Similarly, the closed loop 50 comprises a surface thread part 28d between the integral connection parts 33 and 34 in the front side thread part 28, two penetrating thread parts 45 and 46, and a surface thread part 31 a between the integral connec- tion parts 39 and 40 in the rear side thread part 31. The closed loops 51 and the like are formed in the similar manner.

Since the threads 24 and 25 are disposed in addition to the thread 23 in parallel therewith in the laminar block 20, if the block 20 is cut along various planes, cut block pieces or sub-blocks can be retained integrally. The laminar body 22 may be integrated so as to form the laminar block 20, instead of using three 80 lines of the threads 23, 24 and 25, by the use of a single line of thread, for instance, only the intermediate thread 24, by two lines of threads, for instance, the threads 23 and 25 or, furthermore, by four or more lines of threads. 85 Although the threads 23, 24 and 25 are extended in parallel with each other in the illustrated embodiment, one or more threads may further be extended in the direction crossing to the above-described threads 23, 24 and/or 25 so as to stitch the laminar body 22.

Referring further to the thread 23 in the laminar block 20, each of the first surface thread parts comprises, for instance, the thread part 28a between the integral connection parts 32 and 33 in the thread part 28, the thread part 28b between the integral connection parts 34 and 35 in the thread part 28 or the thread part 28c between the integral connection parts 36 and 37 in the thread part 28. In this case, each of the second surface thread parts comprises, for example, the thread part 31 a between the integral connection parts 39 and 40 in the thread part 31 or the thread part 31 b between the integral connection parts 41 and 42 in the thread part 31. In the case mentioned above, each of the first stitching thread part comprises the thread parts 28a, 44 and 45, the thread parts 28b, 46 and 47 or the thread parts 28c, 48 and 48a. Each of the second stitching thread parts comprises the thread parts 31 a, 45 and 46 or the thread parts 31 b, 47 and 48.

In the thread 23 of the laminar block 20, if each of the first surface thread parts comprises the thread part 28d between the integral connection parts 33 and 34 in the thread part 28 or the thread part 28e between the integral connection parts 35 and 36 in the thread part 28, each of the second surface thread parts comprises, for instance, the thread part 31 c between the integral connection parts 38 and 39 in the thread part 31, the thread part 31 d between the integral connection parts 40 and 41 in the thread part 31 or the thread part 31 e between the integral connection parts 42 and 43 in the thread part 31.

Explanation will be made to the detailed structure of the thread 23 in the laminar block 20 shown in Figure 2 referring to an example shown in Figure 3.

In the embodiment shown in Figure 3, the thread 23 has such an arrangement in the form of a single chain stitch of a thread 54. Specifically, the thread parts 28,31,44,45,46,47,48 and 48a comprise a continuous single strand of thread 54, in which each of the surface thread parts 28a, 28d, 28b, 28e and 28c 6 GB 2 175 321 A 6 in the front side thread part 28 comprises two substantially parallel thread parts of the thread 54, each of the penetrating thread parts 44,45, 46,47,48 and 48a comprises two substantially parallel thread parts of thethread 54 and each of the surface thread parts 31c, 31a, 31d, 31 b and 31e in the rear side thread part 31 comprises one thread part of the thread 54. Both ends 54a, 54b are left free. One end 54a of the thread 54 may, however, be bound to the thread part 31c atthe integral connection part 38 and the other end 54b of the thread 54 may also be bound to the thread part 31 e at the integral connection part 43. The turn back part 54c of the thread 54 is also left free. The part 54c may, however be bound to the thread part 28c at one end of the final penetrating thread part 48a of the single chain stitch. Further, adhesives 55 are preferably applied to the integral connection parts 33,34,35,36,37,38,39,40,41,42 and 43 excepting for the integral connection part 32 for securing adjacent or crossing thread parts in orderto form a plurality of closed loops so that the integration of the laminar body 22 or each cut pieces thereof with the thread 54 or 23 may not be degraded by the disconnection of the thread 54 or 23 at least in one point.

In order to maintain the block or sub-block substantially integrally, the adjacent thread parts constituting the respective crossing parts or branching parts 32 to 43 may not be secured to each other in each of these crossing parts or branching parts 32 to 43 of the thread parts, because there is relatively little fear that the thread or penetrating thread portions may be drawn out of the laminated blankets due to the frictional forces between the blankets and the penetrating thread parts. More specifically, even if any one of the loops 49, 50, 51, 52 and 53 should be disconnected upon cutting of the block 22, other loops can still retain their configuration and prevent those blankets of the laminar block 20 constituting the cut pieces with the loops from being disintegrated individually.

In the case where a relatively large number of surface thread parts 28a, 28b, 31 a, etc and the penetrating thread parts 44,45,46, etc are formed, if a certain loop should be disconnected, it may cause relatively less slacking in the thread of other loops situated at relatively remote places in a short time. Accordingly, securing of the connection parts 33, 34, 35,36,39,40, 41, 42, etc with adhesives may not always be necessary.

The arrangement of the thread 23 in the laminar block 20 shown in Figure 2 will be explained specifically referring to another embodiment shown in Figure 4.

In the embodiment shown in Figure 4, the thread 23 has an arrangement in the form of a lock stitch of two threads 56 and 57, made, for instance, of rayon. Specifically, the upper portions 58, 59, 60, 61, 62 and 63 of the penetrating thread parts 44,45,46,47,48 and 48a, as well as the front side thread part 28 be formed by a continuous single strand of thread 56, while the lower portions 64,65,66, 67,68 and 69 of the penetrating thread parts 44,45,46,47, 48 and 48a, as well as the rear side thread part3l comprise another continuous single strand of thread 57. One or both of the threads 50 and 57 may comprise two or move threads. Each of the surface thread parts 28a, 28d, 28b, 28e and 28c of the front side thread part 28 comprises one of the thread parts of the thread 56, while each of the surface thread parts 31c, 31 a, 31 d, 31 b and 31 e of the rear side thread part 31 comprises one of the thread parts of the thread 57. The penetrating thread part 44 comprises an upper thread portion 58 having two parallel turn back thread parts 58a and 58b of the thread 56 and a lower thread portion 64 having two parallel turn back thread parts 64b and 64c which are turned back so as to be engaged cross-wise at a turn back point 64a to the turn back point 58c of the upper thread portion 58 of the thread 57. That is, the upper thread portion 58 and the lower thread portion 64 constitute the penetrating thread part 44 which is extended substantially continuously so as to withstand the tensile force as a whole. Other penetrating thread parts 45, 46,47,48 and 48a have the similar constitution as that of the penetrating thread part 44.

Adhesives 70 are applied for securing a plurality of adjacent thread parts, each having one end at each of the connection parts 32 to 43, to each other in orderto constitute integral connection parts. The adhesives 70 may not be used when the size of the block is relatively large. In the illustrated embodiment, both ends 56a and 56b of the thread 56 and both ends 57a and 57b of the thread 57 are secured at each of their connection parts 32 and 37 and connection parts 38 and 43 to the adjacent thread parts by means of the adhesives 70. The adhesives 70 are not always necessary when the size of the block is relatively large.

It will also be apparent in the laminar block 20 having thus been constituted as shown in Figure 4 that if the laminar block 20 is cut into sub-blocks,the sub-blocks can be retained integrally by the closed loops contained in each of them. In a case where a larger number of stitches, that is, a large number of penetrating thread parts are present, it is not always necessary to integrate each of the connection parts with adhesives or the likes also in this embodiment.

Although it is desirable for the thread parts constituting the laminar block of this invention that they form a plurality of closed loops as shown in Figures 2 through 4, such a plurality of closed loops may not always be necessary in a case where the number of stitches is relatively large. For instance, as shown in Fi96re 5, a laminar block 72 may comprise a laminar body 22 composed or consisting of a plurality of blankets 21 laminated to each other and a thread 71 stitching the laminar body 22 in the form of a - wave-like stitch---. In the laminar block 72, surface thread parts 73,74,75 and 76 are formed on the surface 27 of.the blanket 26 situated at one surface side of the laminar body 22, while surface thread parts 77, 78, 79, 80 and 81 are formed on the surface 30 of the blanket 29 situated on the other surface side of the laminar body 22. The laminar block 72 contains ten penetrating thread parts 82,83,84, 85, 86,87,88,89, 90 and 91 formed by the -wave-like stitch". In the laminar block 72, each of the first stitching thread parts comprises, for example, thread parts 83,73 and 84, thread parts 85,74 and 86, 7 GB 2 175 321 A 7 thread parts 87,75 and 88 orthread parts 89, 76 and 90, while each of the second stitching thread parts comprises, for example, thread parts 82,77 and 83, thread parts 84, 78 and 85, thread parts 86,79 and 87, 5 thread parts 88, 80 and 89 or threads parts 90, 81 and 91.

In this case, the friction between the blankets and the penetrating thread parts also serves for keeping the block integrated.

In a case if the laminar block 72 is cut along a plane shown by the imaginary line 94, the stitching thread part comprising parts 73,78 and 85 or the stitching thread part comprising parts 87,75 and 88, and the stitching thread part comprising parts 88, 80 and 89 can contribute to the integral retention for each cut block pieces or sub- blocks 72a or 72b within a relatively short period of time after the cutting when the sub-blocks 72a, 72b are not roughly handled as in the case of general mounting operation.

Accordingly, in the case that the laminar block 72 is cut just prior to the use of them in a working place where the cut block pieces 72a and 72b are used, closed loops are not always necessary for the cut block pieces if a relatively large number of stitching thread parts are left in each of the cut block pieces.

In a case where the block 72 is formed with the laminar body 22 being integrated in substantially a non-compression state, the closed loops may not be formed, if a relatively large number of stitching thread parts are provided.

It is of course possible, if desired, to constitute the laminar block by forming the independent closed loop respectively with each of a plurality of threads so that the laminar body can be retained as an integral block.

Figure 6 shows an example where the laminar blocks 20 shown in Figure 2 and sub-block thereof produced by cutting the block 20 are applied to the lining of a furnace wall.

In Figure 6, reference numeral 95 denotes the shell or wall portion of a furnace main body, that is, a part of the furnace wall, for instance, made of metal.

Reference numeral 97 represents a laminar block of a standard size similarto the laminar block 20, and 98 represents a cut piece prepared by cutting the laminar block 20 into an appropriate size corresponding to the configuration of the wall portion 96.

The stack-lining of the blocks 97 and the block piece 98 are made by securing the blocks 97 and the sub-block 98 to the furnace wall 95 by means of adhesives or pins such that the end faces of the laminated blankets is in contact with the inner surface 99 of the furnace wall 95 and they are compressed in the laminated direction 100.

In a case where the block 97 (or 20) is cut into the sub-block 98 at a place of applying the lining workto the furnace wall by means of a hand saw or the like according to the shape of the wall portion 96 to be lined, there is little fear that the cut pieces 98 might be disintegrated individually. It is thus possible, according to this invention to apply the lining work by the use of the blocks 97 and 98 while preparing the block pieces 98 at the working place of the lining.

In the above-mentioned stack-lining, since the fibers are generally arranged in perpendicular to the lining surface, degradation of the blanket due to the exposure to a high temperature in the furnace occurs only at one end of the fibers, and the blanket can withstand higher temperature. In addition, the heat shrinkage in the laminated direction can be compensated by utilizing the restoring or expanding force of the compressed blankets. In this way, the workable or applicable temperature range of the blanket composed of inorganic fibers can significantly be extended.

Explanation will then be made to one example of a method for producing, from the laminar body 22, the laminar block 20 having a thread 23 (single chain stitch by a thread 54) constituted as shown in Figure 3, as well as an apparatus therefor referring to Figures 7(a) through 7(h).

In Figure 7, a sewing needle denoted by 101 is adapted to be displaced in the vertical direction A or B, if desired, by drive means not illustrated and an auxiliary needle denoted by 102 is also displaced in the vertical direction A or B by another drive means not shown. The needle 101 is pointed at its top end 103 and has a recess 105 with a protrusion 104 on the side of the top end 103. The intruding recess 105 capable of engaging and disengaging a thread 107 has an opening 106 on one side of the needle 101, a concave portion 108 capable of retaining a stitching thread 107 on the side of the top end 103 of the needle 101 and a slope 110 on the side of a needle base end 109 along which the stitching thread 107 is readily detached or disengaged. The needle 101 while engaging nothing in the intruding recess 105 is caused to move to the laminar body 22 composed of the blankets 21 from below in the direction A and inserted into the laminar body 22 so that the top end 103 projects out of the laminar body 22. A thread 107 is engaged, with an appropriate engaging means (not shown) if desired, to the top end 103 ofthe needle 101 protruded above the laminar body 22.

The thread 107 can be delivered from a thread roll 111. After engaging the thread 107 on the top end 103, the needle 101 is started to move in the direction B relative to the laminar body 22 while engaging the thread 107 in the concave portion 108 of the recess 105. In this state, thetop end 112 of the auxiliary needle 102 is situated substantially on or adjacent to the lower surface 27 of the laminar body (refer to Figure 7(a)).

The needle 101 is further returned in the direction B while engaging the stitching thread 107 to the recess 105 as shown in Figure 7(b).

In this state, the auxiliary needle 102 is still situated on the lower surface 27 of the laminar body 22. When the needle 101 leaves the surface 27 of the laminated blanket 22 to which it was inserted initially, the auxiliary needle 102 returns in the direction B to its lower end position (Figure 7(c)).

When the needle 101 and the auxiliary needle 102 are lowered to the lower end position, both of them are caused to move rightwardly in the direction C relative to the laminar body 22. Instead of moving the needles 101 and 102, the laminar body 22 may be moved by a predetermined feed amount leftwardly (in the direction D) relative to the needles 100 and 102 and the roll 111. In this case, the roll 111 and the 8 GB 2 175 321 A 8 thread 107takethe positions as shown in the imaginary line in Figure 7 (d). Afteror atthe same timewith the relative movementof the needles 101 and 102 in the direction C relative to the body 22 by an appropriate feed means not illustrated, the needle 70 101 is displaced in the direction A relative to the body 22.

When the top end 103 of the needle 101 is in abutment against the lower surface 27 of the laminar body 22, the auxiliary needle 102 which is moved upwardly in the direction A engages a loop-like thread part 107a of the stitching thread 107 detached from the needle 101 along the slope 110 of the recess 105 of the needle 101 atthe top end 112 thereof.

The auxiliary needle 102 engaging the thread 107 at the top end 112 thereof is moved upwardly in the direction A up to its upper end position where the top end 112 is substantially in abutment against the lower surface 27 of the laminar body 22 and then stopped at that position. Then, the needle 101 is inserted at its top end 103 into the laminar body 22 and continuously moved in the direction A (refer to Figure 7(e)).

The stitching thread 107 is engaged by the adequ- ate engaging means to the recess 105 of the needle 101 which is inserted in and penetrating through the laminar body 22 of blankets 21, in the same manner as in Figure 7(a) (if desired, after moving the roll 111 in the direction C relative to the laminar body 22 by a moving means not illustrated). In this state, the auxiliary needle 102 is kept in abutment against the lower surface 27 of the laminar body 22 and still engages the loop-like thread part 107a of the stitching thread 107 as it is (refer to Figure 7(f)).

Then, when the needle 101 moved in the direction B leaves the laminar body 22 of the blankets 21 as shown in Figure 7(g) or, specifically, when the recess 105 engaged with the next loop-like thread part 107b of the thread 107 leaves the lower surface 27 of the blanket laminar body 22 passing through the looplike part 107a the auxiliary needle 102 releases the previously engaged loop-like thread part 107a of the thread 107 and returns to the lowest position together with or independently from the movement of the needle 101 as shown in Figure 7(h). In this case, the crossing portion 113 of the stitching thread 107 may be bound to secure by means of adhesives or the likes.

The auxiliary needle 102 may be constructed in any optional manner so long as it moves vertically 115 along the side of the needle 101 near the opening 106 of the recess 105 of the needle 101.

In this way, when the needle 101 and the auxiliary needle 102 are returned to the original lowest end position, the needles 101 and 102 are moved in the direction C relative to the blanket laminar body 22, and the needle 101 is inserted through the laminar body 22 of the blankets 21, whereby the state shown in Figures 7(e) is again attained. By repeating the steps shown in Figure 7(e) to 7(h), continuous stitching or sewing (single chain stitch) of the laminar body 22 with the thread 107 can be carried out to produce the laminar block 20.

Explanation will then be made more specifically to an embodiment of an automatic apparatus, that is, an industrial sewing machine for producing the laminar block 22 having the thread 23 constituted as shown in Figure 3 (single chain stitch by one thread 54 for each line) referring to Figure 8 through Figure 11.

Referring at first to the driving mechanism of the sewing machine, a motor 121 is mounted on a machine frame 120 in Figure 8. The motor 121 rotates a main drive shaft 123 rotatably supported by bearings 122,122 at the upper end of the frame 120 by way of a chain not illustrated.

The structure of the portion near the sewing machine needle will then be explained mainly referring to Figure 9 and Figure 10. The main drive shaft 123 is attached at the longitudinal middle part thereof with a crank 124 for converting the rotational movement of the main shaft 123 into the reciprocating movement in the directions E, F. At the lower end of the crank 124, is attached a plate 126 for mounting sewing needles 129 by way of a support member 125. The mounting plate 126 is moved vertically in the directions E, F along guides 127,127 in accordance with the vertical movement of the crank 124 accompanying the rotation of the main drive shaft 123. Sewing needles 129,129,.... are attached, for instance, by the number of twelve by means of bearings 128,128,.... at a pitch, for example, of 50 mm each rotatably in the directions G, H to the lower face of the mounting plate 126. As Already described for the needle 101 in Figure 7, each of the sewing needles 129 is formed at the top end thereof with a needle hook or a recess 130 capable of engaging and disengaging a thread. Each of the sewing needles 129 is supported by a tapered chuck 131 connected to the mounting plate 126 and, further, ensured its vertical orientation by a guide metal 133 attached to a guide metal attaching plate 132. The guide metal attaching plate 132 is biased upwardly by compression springs 135,135 supported by support members 134,134 mounted to the frame 120 and the plate 132 is moved vertically in accordance with the vertical movement of the guide metal reciprocating arms 137,137 which follow the movement of cams 136, 136 mounted to the main drive shaft 123 and interlocks with the vertical movement of the sewing needle 129 in the directions E, F. Below the guide metal 133, is disposed a stripper plate 140 which is caused to move vertically in the directions E, F by an air cylinder device 139 mounted to the bottom of a support member 138 secured to the frame 120. The stripper plate 140, when set to its lower position, presses to secure the upper surface of a laminated members to be stitched as described below. Each of the sewing needles 129, upon its lowering, pene- trates a slit 140a formed in the stripper plate 140 and is further inserted into the laminated members to be stitched therebelow. Further, each of the needles 129 is provided with a pinion 141 at a portion above the tapered chuck 131 for retaining the sewing needle 129, and each of the pinions 141 meshes with a rack 143 caused to displace leftwardly and rightwardly in the directions J, K by an air cylinder 142 mounted to the bottom of the mounting plate 126. Each of the machine needles 129 can carry out forward and reverse rotation in the directions G, H by 180 degree 9 GB 2 175 321 A 9 as the first and the second angle under the control of the rack-pinion mechanism 141,142 and 143.

The forward or reverse 180' rotation is required so that the recess, that is, the hook 130 of each needle 129 may not catch a loop-like thread portion of the thread previously formed and remaining on the upper surface of the laminated members to be stitched when the needle leaves the upper surface of the stitched portion of the members to be stitched, but the angle of rotation is not always restricted to the degree of 180' and the sense of the rotational direction may be the same if the above- mentioned fear can be avoided.

Referring then to a belt conveyor section, a cam 144 is attached at one end of the main drive shaft 123, so that the continuous rotational movement of the main drive shaft 123 is transmitted in the form of an intermittent rotational movement to a shaft 149 by way of a first conveyor driving arm 146 which follows the movement of the cam 144 under the upward bias given by a spring 145, a fulcrum shaft 147, a second conveyor drive arm 148 or the like. The shaft 149 is rotatably supported by the bearings 150a, 150a on a support member 150 secured to the frame 120. The intermittent rotational movement of the shaft 149 causes an intermittent circulating movement of a conveyor belt 151 laid around a roller 149a integrally provided to the shaft 149. The conveyor belt 151 moves the laminated members to be stitched as described latter by a predetermined distance during a period when the machine needle 129 is lifted away from the members to be stitched and, accompanying with the movement of the laminated members, a first upper compression belt 153, a second upper compression belt 154 and a lower compression belt 155 which are laid under stretching between respective idler rollers 152 are circulated while compressing the laminated members. A needle plate 156 is disposed between the conveyor belt 151 and the lower compression belt 155, so as to abut against the lower surface of the laminated members. The sewing needle 129, when lowered to the lowest end, penetrates the laminated members to be stitched and further passes through the slit 156a formed in the needle plate 156. 110 Referring then to a thread handling or control mechanism, a bevel gear 157 is attached at the other end of the main drive shaft 123 and another bevel gear 157a meshing with the bevel gear 157 rotates a thread handling shaft 158. A half-pinion 159 is mounted at the lower end of the thread handling shaft 158 and the half-pinion 159 is adapted to mesh with a whole-pinion 160 only upon lowering of the sewing needle 129. When the whole-pinion 160 is driven by the half-pinion 159, a rotational stand 162 disposed below a needle plate 156 is rotated around an axis 162a by way of a timing belt 161, and a looper shaft 163 attached eccentrically at the upper part of the rotational stand 162 and a looper 164 rotatably mounted to the looper shaft 163 are turned by one rotation in the direction L under the control by the tension of the thread 167 while the top end of the needle 129 is being protruded downwardly. A sewing thread 167 which is wound around a bobbin 165 and adjusted its tension by a tension adjuster 166 passes through the inside of the tubular portion looper 164 in the form of "L".

For example, the sewing machine described above may be positioned upside down so that the sewing needle will be inserted upwardly into the laminated member to be stitched from a lower position.

Explanation will next be made for the case of stitching or sewing a laminar body 169 composed of laminated blankets 168 made of ceramic fibers so as to produce a laminer block by using the sewing machine as described above while mainly referring to Figure 11 (a) through Figure 11 (r).

A laminar body 169 composed of blankets 168.... each with 0.10 of bulk density and 25 mm of thickness laminated, for instance, by fourteen is fed from the right hand side of Figures 9, 10 and 11 by the conveyor belt 151 in the direction M and it is compressed between the conveyor belt 151 and the first upper compression belt 153 to the entire thickness of about 300 mm. In this case, the sewing thread or machine thread 167 passing through the looper 164 passes the slit 156a in the needle plate 156 and is extended leftwardly between the lower surface 169a of the laminar body 169 composed of the laminated blankets 168 and the upper surface 156b of the needle plate 156. While on the other hand, the needle hook or recess 130 of the sewing needle 129 is directed such that it is open to the side opposite to the advancing direction M of the laminar body 169, that is, toward the upstream side with respect to the feeding direction M of the laminar body 169 (refer to Figure 11 (a)).

The laminar body 169 composed of the blankets 168 is moved in the direction M by the conveyor belt 151 (refer to Figure 11 (b)).

About at the same time with the start of the lowering of the machine needle 129 in the direction F, the stripper plate 140 lowers in the direction F to hold the laminar body 169 in cooperation with the needle plate 156 (refer to Figure 11 (c)).

The machine needle 129 lowers further in the direction F by the movement of the crank 124 accompanying the rotation of the main drive shaft 123 and penetrates through the slit of the stripper 140, the laminar body 169 and the slit 156a of the needle plate 156 (refer to Figure 11 (d)).

Then, the looper 164 is subject to one rotation generally around the lowerend of the needle 129 in the direction L by the half-pinion mechanism 159, 160, etc. to wind the machine thread 167 around the sewing machine needle 129 (refer to Figure 11 (e)).

Then, the sewing needle 129 catches the machine thread 167 at the engaging recess 130a of the needle hook 130 and rises upwardly in the direction E, penetrates the needle plate 156 and further passes through the laminar body 169 (refer to Figure 11 ffl).

Just before leaving the laminar body 169, the machine needle 129 is turned by 180' in the direction G by the rack-pinion mechanism 141 - 143 during movement in the direction E, whereby the opening of the needle hook 130 is faced to the downstream with respect to the advancing direction M of the laminar body 169 (refer to Figure 11 (g)).

Further, the machine needle 129 continues to move upwardly in the direction E and after leaving GB 2 175 321 A the laminar body 169, leaves the slit in the stripper plate 140 and arrives at the upper limit position (refer to Figure 11 (h)).

At the upper limit position, the machine needle 129 is caused to rotate by 180' in the direction H by the rack-pinion mechanism 141 - 143 and, as the result, the opening in the needle hook 130 is faced to the original direction (upstream side with respect to the advancing direction of the laminar body 169 (refer to Figure 11 (i)).

About the same time with the operation atthe step in Figure 11 (i), the stripper plate 140 is moved upwardly in the direction E by the air cylinder 139 to arrive at the upper limit position (Figure 11 (j)).

After the machine needle 129 and the stripper plate 140 have reached the uppermost position the laminar body 169 is caused to move in the direction M substantially in its plane by a predetermined distance (feed amount) by the conveyor belt 151. The moving distance defines the length of the stitch or the length of the surface thread part (referto Figure 11 (k)).

Subsequently, the stripper plate 140 is lowered in the direction F by the air cylinder 139 to seize and hold the laminar body 169 in co-operation with the needle plate 156 (referto Figure 11 ([)).

Then, the machine needle 129 is moved downwardly in the direction F, freely passes within the loop-like thread part 167a of the machine thread 167 having been formed in the previous steps, and further penetrates the stripper plate 140, the laminar body 169 and the needle plate 156 (refer to Figure 11 (MW Again, the looper 164 is turned by one rotation in the direction L generally around the needle 129 by the half-pinion mechanism 159,160, etc. to wind the machine thread 167 to the machine needle 129 around its shaft on the side nearer to the base end than the hook portion 130 (refer to Figure 11 (n)).

Then, the machine needle 129 again moves upwardly in the direction E while catching the machine thread 167 at the needle hook 130, passes through the needle plate 156 and further penetrates the laminar body 169 (refer to Figure 11 (o)).

The machine needle 129, just before leaving the laminar body 169, is turned by 180' in the direction G by the rack-pinion mechanism 141 - 143 and the opening of the needle hook 130 faces the down stream with respect to the advancing or feeding direction of the laminar body 169 (refer to Figure 11 (0.

The machine needle 129 further continues to move upwardly, leaves the upper surface of the laminar body 169, passes through the stripper plate 140 and then reaches the upper limit position. As the result, one stitch 170 is completed. In this case, since the needle hook 130 is faced toward the downstream with respect to the advancing direction M of the laminar body 169 in the previous step, there is no problem that the needle hook 130 catches the loop 167a of the machine thread 167 (refer to Figure 11 (q)).

The machine needle 129 having reached the upper end position is turned reversely by 180' (180' rotation in the direction H) by the rack-pinion 130 mechanism 141 - 143, whereby the opening of the needle hook 130 faces the original direction or upstream with respect to the advancing direction M of the laminar body (refer to Figure 11 (r)).

Thereafter, the steps shown from Figure 11 (j) through Figure 11 (r) are repeated, whereby the laminar body 169 composed of the ceramic fiber blankets 168 are stitched or sewed to form a laminar block or an assembly of laminar blocks.

In this case, a stitched product formed by the foregoing stitching may be cut on every predetermined length along the feeding direction M of the laminar body 169 or, depending on the case, on every predetermined length along the lateral direc- tion in perpendicular to the feeding direction of the laminar body 169, to produce laminar blocks of a standard size such as the laminar block 22.

According to the sewing machine as described above, the laminar body composed of the laminated blankets made of ceramic fibers can be readily stitched, and the stitched block-like heat insulating products can be used as they are or after being cut or sliced into sub-blocks for heat insulating or temperature retaining zone, whereby heat insulating layers easy to apply and of a homogenous structure can be formed.

The industrial sewing machine according to this invention is not limited in use to the stitching of inorganic fiberous members but is also applicable to the stitching of natural fibers such as straws or cogongrasses for producing heat insulating materials and cushioning materials for use in houses.

As described above specifically, according to this invention, an industrial sewing machine suitable to the sewing or stitching of voluminous fiberous materials can be provided.

This invention will now be described referring to Examples.

Example 1

Ablanket25 mm inthicknessand 0.13g/cm'in bulk density prepared from raw material composed of A1203 - Si02 by melting in an electric furnace, and blowing and then gathering the same and further applying a needling treatment (DURABLANKET made by Toshiba Monofrax Co., Ltd.) was cut into blanket pieces 21 each sized in 25 mm X 300 mm. Sixteen sheets of such blankets were laminated to form a laminar body 22 and compressed to reduce the thickness by about 25 % in the laminated direction into a size of 25 mm x 300 mm X 300 mm. Then, the laminar block kept in the compressed state was sewed by using a stainless steel needle 101 having 5 mm in diameter and with a pointed top end and by the steps of inserting the needle 101 through the laminar body, engaging an industrial sewingmachine thread 107 (VINYMO 4 having 100% vinylon content manufactured by Kuraray Co., Ltd.) to the intruding recess 105 formed at about 6 mm from the top end 103, returning the needle 101 while engaging the thread 107 at the recess 105, displacing the needle 101 together with the engaged thread 107 by about 25 mm in the direction C shown in Figure 7 where the thread 107 was detached from the intruding recess 105 of the needle 101 and engaged by an 11 GB 2 175 321 A 11 auxiliary needle 102, then inserting onlythe needle 101 again into the laminar body 22, engaging the thread 107 to the intruding recess 105, returning the needle 101 again and then lowering the needle 101 through the loop 107a of the thread 107 engaged to the auxiliary needle 102. Hereinafter, the above described steps were repeated to stitch, the laminar body was stitched at about 25 mm pitch (feeding amount). The laminar block thus stitched had 0.16 g/CM3 of bulk density and retained the size of 25 mm X 300 mm X 300 mm which was substantially the same as the initial size. When the stitched block was bisected along the diagonal direction with the sharp knife, none of the cut pieces or sub-blocks showed change in the bulk density and none of the cut pieces was disintegrated individually.

Example 2

A laminar body 22 was formed by laminating sixteen sheets of the same blankets as used in 85 Example 1 each sized 25 mm in thickness, 150 mm in width and 600 mm in length. The laminar body 22 was sewed or stitched in the same manner as in Example 1 and each of the stitches was secured using instantaneous adhesives at the parts 33, 34, etc. shown in Figure 3 to form individual loops. In Example 2, two stitch lines (for instance, two lines 23 and 25 in Figure 3) were formed, with a distance between the two lines being 75 mm, and a large laminar block of 300 mm x 150 mm x 600 mm (compressed to reduce the thickness by about 25 % in the laminated direction) was thus prepared. The biockwas bisected each in longitudinal and lateral directions (in the direction of 150 mm size and 600 mm size) by using a sharp knife into four cut pieces or sub-blocks each of 75 mm x 300 mm x 300 mm in size. In the similar manner to Example 1, any of the sub-blocks kept the bulk density of about 0.16 g/cm 3 and each of the sub-blocks was well kept in gathered condition with no individual disintegration.

Claims (6)

1. An industrial sewing machine comprising:

a needle driving mechanism for generally vertical iy moving, relative to a member to be stitched, a needle which extends in the generally vertical direc tion and has a recess capable of engaging and disengaging a thread to a side wall at a lower end thereof; a thread winding mechanism for winding a thread by one turn around a portion of the needle protruded from the member to be stitched when the needle is moved downwardly so that the lower end thereof penetrates through the member to be stitched; a moving mechanism for moving the member to be stitched by a predetermined distance relative to the needle in a direction crossing the extending direction of the needle when the lower end of the needle rises above an upper surface of the member to be stitched while engaging the thread in the recess; and a rotational mechanism for rotating the needle by a first angle around a longitudinal axis thereof so as to face the recess toward downstream with respect to the moving direction of the member to be stitched before the lower end of the needle reaches the upper surface of the member to be stitched in the course of the rising of the needle, and for rotating the needle by a second angle around the longitudinal axis thereof so as to face the recess toward upstream with respect to the moving direction of the member to be stitched while the lower end of the needle is being situated above the upper surface of the member to be stitched.

2. The sewing machine of claim 1, in which the winding mechanism has a tubular portion through which the thread is inserted and the tubular portion is adapted to turn by one rotation around the protruded portion of the needle so as to wind the thread around the needle when the needle is moved downwardly penetrating the member to be stitched.

3. The sewing machine of claim 2, in which the winding mechanism further comprises a tension adjuster for giving a predetermined tension to the thread inserted through the tubular portion.

4. The sewing machine of claim 1, in which the moving mechanism comprises belts for seizing the member to be stitched therebetween in a state compressed in a direction of the thickness thereof.

5. The sewing machine of claim 1, in which each of the first and the second angles is 180'.

6. An industrial sewing machine constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Printed in the U K for HMSO, D8818935,10186,7102. Published by The Patent Office, 25Southampton Buildings, London, WC2A lAY, from which copies may be obtained.