Subway tunnels can be divided into rectangular, arched, circular, and elliptical end face forms according to the section shape of the section tunnel. The rectangular end face can be divided into single-span, double-span and multi-span types. There are two types of circles. The subway tunnel needs to install electromechanical equipment through bolts, insert T-shaped bolts into the preset holes on the shield plate of the subway tunnel, and then cast and fix it. The bolts are smooth and the contact surface is small. The bolts installed in the shield plate are easy to fall off, causing the installed equipment to fall and damage or causing losses to pedestrians or vehicles passing in the tunnel. Therefore, it is necessary to further improve the current bolts.
structure for concealing installation screws, comprising a locking piece, a driving piece, a bottom plate, a blocking cover and a handle head, the lower ends of the two locking pieces are provided with positioning holes, and the locking pieces pass through the positioning holes and the locking piece positioning posts on the base Snap and fix, the middle of the two locking pieces is provided with a protruding point, the movable groove of the driving piece corresponds to the protruding point of the nine locking pieces for fixing, the riveting point holes and screw holes of the bottom plate and the riveting points of the base The position that matches the screw holes and is fixed by screws, the blocking cover is directly inserted into the bottom plate, and the blocking cover is fixed by the rotating drive piece, the handle head is inserted into the base, and the slot of the handle head moves to the locking piece at the locking piece Lock the handle.
slotted screw comprises a screw rod, one end of the screw rod is connected to the middle of the bottom surface of the screw head, the side wall of one end of the screw rod away from the screw head is provided with a screw slot in the vertical direction, the screw The bottom surface of the head is in seamless contact with the top surface of the buffer wear-resistant pad, the buffer wear-resistant pad is connected with the screw rod by threads, and the buffer wear-resistant pad is provided with several shock-absorbing holes equally spaced along the circumference.
Self-tapping screw is a kind of threaded fastener that self-tapping and drilling the matching female thread in the pre-drilled hole of metal or non-metal material. When using self-tapping screw, a flat washer is often required to protect the fastening surface. Traditional When the self-tapping screw is used, the flat pad is easy to fall off, resulting in low work efficiency. In view of this, we propose a combined structure of the stuck self-tapping screw spring washer that prevents the flat pad from falling off.
Most of the existing belts control the length of the belt by fixing the other end of the belt by the buckle, and the period that is often buckled by the buckle will be deformed and damaged after long-term use, and the user may change the position from standing to sitting or after meals. The circumference of the belt can be adjusted, and micro-adjustment is not necessarily possible when adjusting the tightness of the pin buckle type or buckle plate type belt buckle. In order to solve this problem, it is necessary to design a belt that is relatively suitable for the waist of a person.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: expansion tube screws, hexagon socket screws, metric hexagon nuts, slider nuts and other products, we can provide you with suitable tightening. piece solution.