Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D37/00—Circular looms

Definitions

• the present invention is related to shuttles utilized in circular weaving looms; in particular it relates to a weft unwinding and tensioning system and a circular loom shuttle that incorporates the shuttle pad assembly and a circular loom that deploys the shuttle carrying the shuttle pad assembly.
• the circular loom has been recognized as one of the most practical weaving machines for producing tubular fabric, which is preferably used as a base material-fabric for making a transportation container or a storage container of granules, such as grains, sugar, fertilizers, polymer granules and chemicals.
• granules such as grains, sugar, fertilizers, polymer granules and chemicals.
• an even number of shuttles is mounted on an annular shuttle guide member so that they can travel along this guide member.
• Engaging means to be engaged with corresponding shuttles, respectively, such as press rollers, are moved along the shuttle guide member. Each shuttle is pressed by the corresponding engaging means and propelled along the shuttle guide member.
• Wefts taken out from the respective shuttles are fabricated with warps sequentially opened on both the upper and lower sides of the respective shuttles by healds, and a tubular fabric is thus formed.
• slit film strip material made of polypropylene are slightly stiffer and rougher than the softer and smoother tapes made from polyethylene material.
• the braking force generated by a pressure pad (or a brake pad) being acted directly on the thread or strip material, continuous abrasion could lead to damage to the brake material. This may further lead to uneven tension control, if pressure pads are not regularly replaced. Also, it may damage the weft tape material. The replacement of pressure pads lead to decrease in productivity of loom and expense on consumable items.
• WIPO publication W02010084074A1 discloses a device for controlling the weft band tension on a shuttle, shuttle and a circular loom equipped therewith.
• the publication makes a reference to the brake liners used in the shuttles deployed in the circular looms and how the pressure applied by the brake liners is instrumental in generating tension in the weft yarn.
• US patent 4365651 also discloses a shuttle utilized in a circular loom.
• this document discloses a shuttle that is provided with an improved structure for easily mounting on or dismounting from said circular loom while providing a stable structure that is able to support large size bobbins.
• One object of the present invention to provide a shuttle pad assembly system deploying a pressure pad assembly which has enhanced wear resistance and at the same time is gentle on the weft material.
• Another object of the present invention is to provide a shuttle pad assembly system deploying a pressure pad assembly which is cost-effective and having long service life.
• a further object of the invention is to provide a shuttle that employs a shuttle pad assembly which has a pressure pad assembly with enhanced wear resitance.
• a still further object of the invention is to provide a circular loom that employs a shuttle having a shuttle pad with a pressure liner that has enhanced wear resistance.
• Figure 1 shows a schematic of the working of the braking system used in a circular loom
• Figure 2 shows the pressure pad assembly arrangement of the invention.
• Figure 3 shows a number of alternatives of the cross-sectional curvature of the pressure pad liner
• Figure 4 shows a perspective view of the pressure pad liner List Of Parts:
• the invention discloses a shuttle pad assembly (S A ) that incorporates a pressure pad assembly (2) that is harmless to the yarn as well as to itself.
• the pressure pad assembly (2) is provided at one end of the tension arm (1).
• the pressure pad assembly (2) has a pressure pad liner (2A) that is mounted on a pressure pad receiver (2B) which is connected to the tension arm (1).
• Figure 2 shows the pressure pad assembly (2) of the invention.
• the tension arm (1) connects the pressure pad assembly (2) to a pivot mechanism (3) which is affixed to the shuttle body.
• the pivot mechanism (3) is connected to a fixed support (5) through a tension spring (4).
• the pressure pad liner (2A) of the invention is made of hard wearing such as metals such as stainless steel or alloy steel. They may be made from sheet metal or shaped by machining solid metal block.
• the invention also discloses a shuttle that incorporates the shuttle pad assembly as disclosed here and a circular loom that deploys the shuttle carrying the shuttle pad assembly disclosed here. Description:
• the unwinding tension of yarn from wound bobbins (B) is a very important criterion determining the quality of the product. It has been observed that the nature and magnitude of variation in yam tension depend on the size of the bobbin (B) at the start and end of the unwinding process. The tension increases both with the depletion of bobbin (B) and with the increase in unwinding speed of the bobbin (B).
• the weft yarn unwinding tension is controlled by a shuttle pad assembly (SA).
• SA shuttle pad assembly
• the shuttle pad assembly (SA) rotates around a pivot point with the help of a tension spring mounted on the shuttle body.
• the shuttle pad assembly (SA) also has a mechanism to control the speed of the rotating bobbin, typically a pressure pad assembly (2) that presses on the weft bobbin surface (refer to Figure 1).
• the material of this contact surface should be such that it does not cause damage to the yarn. At the same time the material should be such that it does not get worn out itself from the friction.
• the pressure pad assembly (2) provided in the shuttle pad assembly (SA) has a pressure pad liner (2A) that is made of leather or felt, which pressed against the weft bobbin. This material is found to be generally harmless to the yarn, however, it has been found that as the weft yarn runs through the pressure pads made of felt or leather, the contact surface of the pressure pad liner (2A) wears out due to constant abrasion with the yarn. This leads to frequent change/replacement of the pressure pad liner (2A) depending on the type of yarn material of weft bobbin (B).
• FIG. 1 shows a bobbin (B) that is being unwound and the shuttle pad assembly (SA). It shows a pressure pad assembly (2), which is a part of the shuttle pad assembly (SA), that exerts pressure on the outside face (7) of the wound bobbin (B).
• the pressure pad assembly (2) comprises a pressure pad receiver (2B) on which a pressure pad liner (2A) is mounted.
• a connecting arm or the tension arm (1) connects the pressure pad assembly (2) to a pivot mechanism (3) that is in turn affixed to the body of the shuttle that carries the bobbin.
• the pivot mechanism (3) is connected to a fixed support (5) that is also affixed to the shuttle body through a tension spring (4).
• a tension spring (4) develops tension in the tension arm (1).
• the pressure pad assembly (2) presses onto the weft bobbin (B), thereby hampering the uncontrolled free rotation of the weft bobbin (B), which in turn leads to developing a pre-determined amount of tension in the weft yarns.
• the diameter of weft bobbin (B) gradually decreases.
• the outer diameter of the wound package for full package size of the weft yarn bobbin is about 110 to 90 mm (represented by Di in Figure 1), whereas towards the end, the outer diameter of the empty bobbin is around 35 to 40mm (represented by D 0 in Figure 1).
• the shuttle pad assembly is designed to exert pressure through its pressure pad liner (2A) on the outer surface (7) of the full bobbin (B).
• the deformation of the tension spring (4) is Li.
• the brake pad With time, as the weft bobbin diameter decreases, the brake pad now acts on the outside surface (7) of the bobbin (B), which has a reduced diameter D 0 , and the spring deformation reduces to L 0. At this point, the traction force to overcome the frictional and the tension force generated by the pressure pad assembly (2) also reduces.
• the invention discloses a shuttle pad assembly (SA) that incorporates a pressure pad assembly (2) that is harmless to the yarn as well as to itself.
• the pressure pad assembly (2) is provided at one end of the tension arm (1).
• the pressure pad assembly (2) has a pressure pad liner (2A) that is mounted on a pressure pad receiver (2B) which is connected to the tension arm (1).
• Figure 2 shows the pressure pad assembly (2) of the invention.
• the tension arm (1) connects the pressure pad assembly (2) to a pivot mechanism (3) which is affixed to the shuttle body (shown indicatively as S B ).
• the pivot mechanism (3) is corrected to a fixed support (5) through a tension spring (4).
• the pressure pad liner (2A) is mounted on the pressure pad receiver (2B) by any one of the number of arrangements selected from screw-on type, or glue-on type, or press-fit clip-on type, or a combination thereof.
• the pressure pad liner (2A) of the invention is made of hard wearing material such as metals, for instance stainless steel or alloy steel. They may be made from sheet metal or shaped by machining solid metal block.
• the texture of the outer surface (6) of the pressure pad liner (2A) that comes in contact with the bobbin (B) is of importance.
• the outer surface (6) is polished to reduce its friction coefficient as much as possible, preferably to between 0.1 and 0.25.
• the pressure pad liner (2A) may be made of any material as a base material and on which a hard-wearing coating/abrasion resistance coating using a number of technologies such as like nitriding or hard anodizing or chrome plating or plasma electrolytic oxidation, or chrome carbide, or chrome oxide, or tungsten carbide or ceramic coating may be provided.
• the coating surface has roughness preferably in the range between 0. land 2.3 micron Ra.
• the outer surface (6) has a preferably curved cross-sectional geometry as shown in Figure 3.
• a single hump is provided in the pressure pad liner (2A), and which runs over the entire length of the pressure pad liner (2A).
• the pressure pad liner (2A) may have a multiple-hump contact surface (6). As shown in part
• the outer surface (6) may have a double hump, or as shown in part
• the pressure pad liner (2A) is mounted on the pressure pad receiver (2B) by any one of the number of arrangements or their combination.
• the mounting arrangement may be of a screw-on type or the pressure pad liner (2A) may be glued on to the pressure pad receiver (2B) using suitable type of glue.
• the shape of the pressure pad liner (2A) may be such that it may be in the form of a clip that may be press fitted onto the receiver (2B).
• the pressure pad liner (2A) of the shuttle pad assembly (S A ) disclosed in the invention has been provided with wear resistant treatment like plasma electrolytic oxidation coating or carbide coating, leading to very long service life.
• the base material of the shuttle pad liner may be hard wearing plastic like PEEK, acetal, or UHMW.
• the invention also discloses a shuttle assembly incorporating the shuttle pad assembly.
• the shuttle pad assembly of the invention requires less frequent replacements of the pressure pad liner (2A) as compared with the existing shuttles that deploy brake pads.
• the invention also discloses a circular loom that deploys shuttles using the shuttle pad assembly disclosed here. The loom of the invention requires fewer shutdowns to replace the brake pad liners (2A).

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Looms (AREA)
• Woven Fabrics (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=74684116

Family Applications (1)

Country Status (5)

Family Cites Families (14)

• 2020
  • 2020-08-19 WO PCT/IB2020/057804 patent/WO2021038388A1/en unknown
  • 2020-08-19 CN CN202080059996.7A patent/CN114286877A/zh active Pending
  • 2020-08-19 BR BR112022003501A patent/BR112022003501A2/pt unknown
  • 2020-08-19 EP EP20856617.4A patent/EP4018026A4/de not_active Withdrawn
  • 2020-08-19 MX MX2022002009A patent/MX2022002009A/es unknown

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