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Saturday, 7 June 2014

Locking Devices for Bolts and Nuts

Locking Devices for Bolts and Nuts Points : Locking Devices for Bolts and Nuts, Penn, Ring or Grooved Nut, Jam Nut or Lock Nut, Locking with Pin, Castle Nut, Locking with Plate, Sawn Nut, Spring Lock Washer Common thread fastenings, commonly, continue tight below static loads, but several of these fastenings become loose under action of changeable loads or as machine is subjected to vibrations. Loosening of fastening is extremely unsafe and has to be prevented. In order to prevent this, a large amount of locking devices are presented, several of which are discuss under:
1. Penn, Ring or Grooved Nut
2. Jam Nut or Lock Nut
3. Locking with Pin
4. Castle Nut
5. Locking with Plate
6. Sawn Nut
7. Spring Lock Washer
1. Penn, Ring or Grooved Nut It has an upper part hexagonal with a lower part cylindrical. It is mostly use where bolts exceed during attached pieces practically close to their edges for instance in marine type connecting rod ends. The floor part is cylindrical with is recessed to receive tip of locking set screw. Bolt hole requires counter-boring to obtain cylindrical part of nut. In order to put off streak of latter by case hard-bitten tip of set screw, it is buried.
2. Jam Nut or Lock Nut A mainly regular locking mechanism is a jam, lock or check nut. It has concerning one-half to two-third width of standard nut. Thin lock nut is first tightening down by ordinary force, with the upper nut is tightened down ahead it. The upper nut is then held closely as the lower one is slackened back beside it. In slackening back lock nut, a thin spanner is necessary which is hard to find in various shops. Thus to defeat this trouble, a thin nut is located on top. If nuts are truly tightened down as they must be, the upper nut carries a better tensile load than bottom one. Then, the top nut must be thicker one by a thin nut under it as it is enviable to put entire of load on thin nut. In order to defeat equally difficulties, both nuts are prepared of similar thickness.
3. Locking with Pin Locking nuts might be locked by means of a taper pin and cotter pin passing through center of nut. But a split pin is frequently motivated through bolt above the nut.
4. Castle Nut Castle nut is consists of a hexagonal part by a cylindrical upper part which is slot in line by centre of every face. Split pin pass during two slots in nut with a hole in bolt, so that a positive lock is obtain except pin shears. It is broadly use on jobs subjected to sudden shocks with extensive vibration for example in automobile industry.
5. Locking with Plate Nut can be adjusted with subsequently locked through angular intervals of 30° by with these plates.
6. Sawn Nut Sawn nut has a slot sawed on partly way through. After nut is screwed down, small screw is tightening which create more friction among nut with the bolt. This put off the loosening of nut.
7. Spring Lock Washer Spring lock washer as nut tightens the washer beside the piece below; one edging of washer is cause to dig itself into that piece, Hence raising the resistance so that nut will not untie so simply. There is several type of spring lock washers pretend, some of which are quite effective.

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