螺栓

L-shaped ground bolts, buried in concrete foundations, for fixing the base of various machines and equipment.
 

U-shaped bolts are named after their U-shaped shape and are threaded at both ends to allow them to be combined with a nut. They are mainly used for fixing tubular objects such as water pipes or leaf-shaped objects such as leaf springs in cars.
 

T-shaped bolts are suitable for occasions where the bolt can only be connected from one side of the part being connected. Insert the bolt from the T-slot and then turn 90°, so that the bolt can not be taken out; also used in the occasion of compact structure requirements.
 

The head of the countersunk head square neck bolt, a 90 degree cone, is similar to the common countersunk head bolt, with tool tightening slots in the head in the form of a zigzag, cross, hexagonal, etc. On the surface of the mounting hole in the connection, a 90 degree conical nub is machined and the head of the countersunk square neck bolt is inside this nub, flush with the surface of the connection.
 

Common half-round head bolts are used on metal parts, large half-round head bolts are used on wooden parts, and reinforced half-round head bolts are used on occasions subject to shock, vibration or alternating loads.
 

Square head bolts have a large square head size, which makes it easy to jam with a spanner or rely on other parts to act as a stopper; they can also be used in parts with T-slots to adjust the bolt position.
 

Hexagon socket bolts are similar to countersunk head screws, with the nail head buried in the machine part and a stronger connection, but the corresponding hexagonal spanner must be used to install and remove the screw. Generally used on various machine tools and their accessories.
 

The bolt strength is high and the compressive stress of the connected parts is relatively low, adding flat washers can reduce the compressive stress on the bearing surface of the connected parts. In order to ensure that the bolt holes between the two connections can correspond one to the other, we need to increase the diameter of the holes to compensate for the deviation in the position of the holes, the bolt holes exceed the standard requirements when you need to increase the flat washers.
 

The head of a hexagonal flange bolt consists of two parts: the hexagonal head and the flange surface. The ratio of the bearing area to the stress area is greater than that of a normal hexagonal head bolt, so this bolt can withstand higher preload and has better loosening resistance, and is therefore widely used in automobile engines and heavy machinery.