A method of and a loom for producing a tape having a list with laterally protruding loops

Claim 2

In a method of manufacturing a tape by weaving a weft thread with warp threads distributed into two main warp sheets that are alternately inclined with respect to one another thus successively forming sheds into which the weft thread is introduced from a weft-picks insertion side in the form of weftthread double picks, and providing said tape along one of its two longitudinal edges with a list having successive list-thread loops protruding laterally from this list, the improvement which comprises the steps of: superposing an auxiliary sheet of auxiliary warp threads over at least a part of one of said main warp sheets located to the weft-picks insertion side; constraining said auxiliary sheet to follow each shed-forming movement executed by said one of said main warp sheet during weaving; inserting at least during some of said shed-forming movements between said one main warp sheet and said auxiliary warp sheet, a list thread as a double pick constituted by two parallel portions of this list thread connected by a third portion forming a head of the double pick, each insertion being in a direction opposite to that of said weft-thread double picks; retaining externally of the sheets said heads of the list-thread double picks; and releasing these heads upon completion of several shed-forming movements after insertion of the list-thread double pick whereby the said list-thread double pick heads form upon the protruding list-thread loops.

Claim 3

The improvement defined in claim 1, further comprising the step of covering the list thread over the entire circumference of its cross-section with a layer of deformable material forming a sheath.

Claim 4

The improvement defined in claim 1, further comprising the step of providing said list thread over part of its cross-section with a layer of synthetic material forming a longitudinal bead.

Claim 5

The improvement defined in claim 1, further comprising the step of applying to said list thread a layer of deformable material only at those places which are intended to constitute said list pick heads.

Claim 6

The improvement defined in claim 1, further comprising the step of premarking said list thread by a deformation of its cross-section at locations constituting the list-thread heads.

Claim 7

The improvement defined in claim 1, further comprising the step of filling said list thread in the form of a tube with a soft material.

Claim 8

The improvement defined in claim 1, further comprising the step of forming said list thread as a filiform element with a cross-section of periodically varying area and/or shape.

Claim 9

The improvement defined in claim 1 wherein said list thread is a filiform element which, at those places which are intended to constitute the list-thread double pick heads, is formed at least in part of a deformable material, and which comprises the further step of: producing at the apexes of said list-thread double pick heads a permanent deformatiOn of the filiform element''s cross-section thereby to widen said cross-section in a direction parallel to the edge of the tape and to impart to said protruding loops the required shape for them to act as hooking elements in a sliding clasp fastener.

Claim 10

In a needle loom for manufacturing a tape having a list-thread provided with protruding loops and comprising means for separating the warp threads into two main sheets and for imparting to said sheets an alternate shed-forming movement, and a weft needle associated with a weft hook for inserting between said main sheets a weft thread in the form of double picks from a weft-thread insertion side, the improvement which comprises: means for forming an auxiliary sheet consisting of auxiliary warp threads superposed over at least a part, located to the weft-thread insertion side, of one of said main sheets and for compelling this auxiliary sheet to follow the shed-forming movement of this main sheet; an auxiliary needle for inserting, from the side opposite to the weft-thread insertion side, a list thread into the space between said auxiliary sheet and its associated main sheet, thus forming list-thread double picks; and means for retaining the heads of the list-thread double picks, said retaining means including a free needle disposed parallel to the tape side which is remote from the location at which the auxiliary needle enters said space, said free needle having a position with respect to the trajectory of the auxiliary needle such as to allow the heads of said list-thread double picks to entwine the free needle, thus being retained outside the tape in a transverse direction, and to slide longitudinally over the free needle while moving with the tape, said retaining means further including maintaining means able to hold the free needle in the same position before each entwinement by the list-thread double pick heads.

Claim 11

In a needle loom for manufacturing a tape having a list-thread provided with protruding loops and comprising means for separating the warp threads into two main sheets and for imparting to said sheets an alternate shed-forming movement, and a weft needle associated with a weft hook for inserting between said main sheets a weft thread in the form of double picks from a weft-thread insertion side, the improvement which comprises: means for forming an auxiliary sheet consisting of auxiliary warp threads superposed over at least a part, located to the weft-thread insertion side, of one of said main sheets and for compelling this auxiliary sheet to follow the shed-forming movement of this main sheet; an auxiliary needle for inserting, from the side opposite to the weft-thread insertion side, a list thread into the space between said auxiliary sheet and its associated main sheet, thus forming list-thread double picks; and means for retaining the heads of the list-thread double picks, said retaining means including a free needle disposed parallel to the tape side which is remote from the location at which the auxiliary needle enters said space, said free needle having a position with respect to the trajectory of the auxiliary needle such as to allow the heads of said list-thread double picks to entwine the free needle, thus being retained outside the tape in a transverse direction, and to slide longitudinally over the free needle while moving with the tape, said retaining means further including maintaining means able to hold the free needle in the same position before each entwinement by the list-thread double pick heads.

Claim 12

The improvement defined in claim 9 wherein the free needle comprises a head located in alignment with the shed and a shank located in alignment with the tape, said shank having a smaller cross-section than that of the head and said head being connected to the shank by rounded surfaces.

Claim 13

The improvement defined in claim 10 wherein said head has the form of a butt that is delimited, along the side remote from the tape, by a concave outline and, along the side adjacent the tape, by a rectilinear outline.

Claim 14

The improvement defined in claim 10 wherein said head has the form of a ball secured at the end of said shank in an eccentric position in relation to the longitudinal axis of the shank, the offsetting being directed away from the tape.

Claim 15

The improvement defined in claim 10 wherein said head has the form of a nose that is curved away from the tape.

Claim 16

The improvement defined in claim 10 wherein said maintaining means include an abutment adapted to cooperate with said head so as to prevent it from rotating about its longitudinal axis and from being entrained longitudinally with the moving tape, thus holding said free needle in a given working position.

Claim 17

The improvement defined in claim 14 wherein said abutment is a movable abutment wherein means is provided for imparting thereto a reciprocatory movement in a direction parallel to the motion of the tape, said reciprocatory movement including a withdrawal phase, in the direction of said motion, during which the abutment releases said head, and an advancement phase, in a direction opposite to said motion, during which the abutment returns the head to its initial position, the withdrawal phase beginning with the entwinement of the free needle head by the list-thread pick head and the advancement phase beginning after such entwinement.

Claim 18

The improvement defined in claim 14 wherein said abutment is a stationary abutment endowed with the resiliency that is required to enable the head of the list-thread double pick inserted by the auxiliary needle to entwine the head of the free needle, by elastically moving the abutmeNt away from said head.

Claim 19

The improvement defined in claim 10 wherein the shank of the free needle has the shape of a bevel, whose ridge is located to the side remote from the tape list.

Claim 20

The improvement defined in claim 10 wherein the shank of the free needle has a cross-section of which the shape varies along said shank.

Claim 21

The improvement defined in claim 10 wherein the shank of the free needle has a cross-section of which the area varies along said shank.

Claim 22

The improvement defined in claim 19 wherein the variation of said area is continuous.

Claim 23

The improvement defined in claim 19 wherein the variation of said area is discontinuous.

Claim 24

The improvement defined in claim 9 wherein said maintaining means consists in a variation of the shape and area of said cross-section, said variation imparting to the free needle the shape of a sharp wedge having a slope so chosen that the free needle may be subjected, under the action of the tension in the list-thread, to a longitudinal force capable of compensating the driving force to which it is subjected under the effect of the tape motion.

Claim 25

The improvement defined in claim 9, further comprising deforming means capable of producing, at the apexes of said list-thread double pick heads, a permanent deformation of the cross-section of the list thread, such deformation having the effect of broadening this cross-section in a direction parallel to the longitudinal axis of the tape whereby the tape may be utilizable as one of the halves of a sliding clasp fastener of which the hooking elements are formed by said protruding loops.

Claim 26

The improvement defined in claim 23 wherein said deforming means include a crushing member having a slope adapted to cause progressive crushing of said list-thread double pick heads against the shank of said free needle while they slide along the shank.

Claim 27

The improvement defined in claim 23 wherein said deforming means include a hammer adapted to crush said list-thread double pick heads against the shank of said free needle by hammering them while they slide along the shank.

Claim 28

The improvement defined in claim 23 wherein said deforming means include a heating device capable of locally heating said list-thread double pick heads while they slide along the shank of said free needle.

Claim 29

The improvement defined in claim 26 wherein said heating device includes a nozzle projecting a jet of hot air onto said list-thread double pick heads.

Claim 30

The improvement defined in claim 23 wherein said deforming means include a generator of ultrasonic vibrations adapted to irradiate with ultrasonic waves said list-thread double pick heads while they slide along the shank of said free needle.