Lashing strap
Lashing straps (also lashing straps , Swiss tensioning set ) are woven straps with a lock for attaching and lashing objects. Lashing straps are made of polypropylene , polyester , nylon or cotton and a fitting made of metal or plastic.
material
The webbing of high-quality tension belts is manufactured in mechanical weaving mills , mainly from polyester tape material. The webbing of very high quality, high-performance tension belts for special purposes such as climbing, flying etc. is made of nylon. To reduce the stretch during use, the straps are pre-stretched . In order to compact the surface and to make the belts more resistant to dirt, they are impregnated. Standard belts are produced in widths of 25, 35, 50 and 75 mm, with tear strengths between 250 and 10,000 daN (1 Deka Newton = 10 Newton).
Fittings, d. H. Clamping element or connecting element are always sewn in firmly with special safety seams. A strip of fabric with printed test features (material, tear resistance, test standard) is sewn in at this point.
use
There are different uses for tension straps. There are statutory regulations for load securing belts in road traffic, but not for those on hiking backpacks. In order to meet the regulations, tear resistance properties are required which are met by polyester or nylon and which pass the test on load test machines.
The area not regulated by law is based on ease of use and a low overall weight. In the leisure sector, simple lashing straps are common for closing bags and rucksacks, or for lashing objects to pieces of luggage. So-called packing straps (or straps), colloquially also tied or lashing straps (or straps), have their own development history. Perforated leather straps or perforated and riveted cotton straps with belt buckles were common until 1950, at the same time leather straps or cotton straps without holes, but with clamping devices. These were made of metal and the entire arrangement was determined by the consideration of not allowing the lock to be opened accidentally. There were two different lock principles: one lock without moving parts and one with moving parts. The immovable fasteners were based on the idea of increasing the friction so that slipping under load was prevented, but lashing and lashing was possible. The variants with moving parts again differ in three forms: the double ring lock, the press-clamp buckle and the glides with or without teeth. The basic problem with slider locks is jamming under load. The basic problem with press-clamp buckles is accidental loosening when you get stuck and z. B. pushes a branch under the lever. The basic problem of the double ring lock is the possible slow slipping. The development of pressure elements, which were pressed on by small helical springs, set new standards and has replaced almost all predecessors today. In the beginning, the jagged glider was imitated, and again the goal of captivity was in the foreground. The further development of the aluminum and zinc die-casting processes in the 1960s enabled a solution in the three-dimensional area, the clamp closure, which is still known today, which ultimately prevailed due to a favorable mix of easy handling and security against loss, as well as an even simpler manufacturing process compared to pressed steel parts .
Closures
Turnbuckle
Lashing straps are closed with a fitting made of cast metal or formed sheet steel. The name of the fitting is turnbuckle or clamp lock. The closure consists of a deflection bar and a fluted clamping jaw that is pressed onto the bar with a spring. The belt strap can be pulled through in one direction, in the other it is blocked by the clamping jaw. The angle of incidence of the clamping jaw in relation to the web is decisive for the clamp lock to be able to be released even under load.
ratchet
Tensioning forces of up to 500 daN can be generated with normal ratchets. Special designs are already available for preload forces of up to 1000 daN. High quality ratchets are made of stainless steel or are fully galvanized. There are three types of professional load securing (trucks): the long-lever ratchet , the short-lever ratchet and the heavy-duty ratchet . In addition, the ratchets are divided into three groups, in which the direction in which the force is exerted to generate the pretensioning force is specified: the pull ratchet, the push ratchet and the multi-ratchet for push and pull. In the case of particularly high-quality ratchets, the lever can be removed from the ratchet after tensioning.
End fitting
Depending on the area of application, tension belts are equipped with or with different end fittings. Common are claw hooks, claw hooks with clasp, triangle (bracket, eyelet), triangle hook, claw hook, frame hook, flat hook.
A free end is usually cut by melting so as not to fray - usually at right angles across, rarely 45 ° diagonally.
Backpack straps, especially those for adjusting the shoulder straps, are typically turned back at the end and sewn once across so that the end just before the fold acts as a barb that - if the threading is correctly oriented - hooks onto the angular web of the buckle and the strap slips out from the buckle and thus the risk of the rucksack slipping off if the shoulder strap is kept on for a longer period while walking.
Safety standards
Industrially used tension belts are tested according to the DIN 60060, VDI 2701 and / or EN 12195-2 standards, depending on the area of application. The permissible breaking loads are printed on a sewn-in blue test label. Lashing straps (like lifting gear ) must be checked regularly. Lashing straps must be checked for damage before each use and replaced immediately if they are defective. Belts with a missing test label may no longer be used. Special edge protection is required for lashing sharp-edged objects (e.g. sheet metal).
The test label in the picture on the right provides information about:
- Test certificate
- S HF = 50 daN = Standard Hand Force (hand tensioning / hand pulling force) - the lever may only be pulled with this force.
- S TF = 200 daN = Standard Tension Force - maximum belt tension or: "The remaining force after the handle of a tensioning element has been tightened to 50 daN and then released."
- LC = 1000 daN = Lashing Capacity ((permissible) tensile force) - single belt
- AU: 07-01855 - test number; 02/07 - test date
- SR320-872 - type number; 0.8 + 4.0m - strap length.
Road traffic regulations
Extract from § 22 of the German Road Traffic Regulations (StVO):
The load, including equipment for securing the load and loading equipment, must be stowed and secured in such a way that, even in the event of emergency braking or sudden evasive movements, they cannot slip, fall over, roll back and forth, fall or generate avoidable noise.
A traffic accident due to insufficiently secured cargo has the following consequences:
- if only property damage was caused: traffic offense report with fine and points in Flensburg.
- if people were injured or killed: criminal charges with a fine or imprisonment.
See also
literature
- Trade association for vehicle maintenance: Load securing on vehicles. Manual for entrepreneurs, resource planners, driving and loading staff.
Web links
- Legal basis for securing loads (PDF) Archived from the original on November 1, 2014. Retrieved on April 13, 2017.