Lifting straps of any material must be back-stitched. The stitching must be intact, otherwise the load-bearing capacity will be affected. The original material of the suture used should be the same as the original material of the webbing. The stitches of the sling to be sewn are controlled to 10-12 stitches within 10CM.
The first step: braided lifting straps
The tape is woven from fabric without any obvious defects, and all threads should be made of the same material during the weaving process. Standard widths are 25mm, 35mm, 50mm, 75mm, 100mm, 150mm, 200mm, 300mm.
Step 2: Pay attention to deviations
Allowable deviation of bandwidth, when the bandwidth is 100mm, the allowable deviation is 10%; when the bandwidth is greater than 100mm, the allowable deviation is 8%. The thickness of the belt should be uniform. When the lifting belt is composed of multiple belts, the thickness of each belt is the same.
Step 3: Sewing the sling
1. The seam should be sewn with the same thread as the material of the belt, and the seam should be smooth;
2. When stitching, the suture should leave a distance to the width edge of the tape, the thickness of the tape should not exceed 10mm, and 24mm should not be stitched. For the thickness greater than 10mm, leave 48mm without stitching;
3. The sutures should be back stitched at the end, and the backstitch length should not be less than 25mm.
Step 4: Length setting
The soft ring of the flat lifting belt should not reduce the carrying capacity of the belt, and the length of the soft ring should meet the following requirements:
1. When the strap width is 2535mm, the length of the soft ring should be 100mm;
2. When the width of the strap is 50150mm, the length of the soft ring should be 3 times the width of the strap;
3. When the width of the strap is greater than 150mm, the length of the soft ring should be 2.5 times the width of the strap.
Step 5: Set up metal parts
The end-piece is a metal piece mounted on the sling soft ring. It is required that the inner diameter of the sling soft ring matched with it should not be less than 2.5 times the diameter of the end piece. The breaking strength of the metal material of the end piece shall not be less than 4 times the limit working load of the sling. Castings are not allowed for the end pieces.