While the familiar Type R safety vest and safety jackets serve to increase the visibility of the wearer, a helmet is a type of hat that protects a person's head from falling objects and other specific elements.
Structural composition
A helmet consists of a shell, liner, chin strap and accessories.
The safety hard hat is composed of three parts: the cap shell, the cap liner and the chin strap.(1) Cap shell: This is the main part of the helmet, and generally adopts an oval or hemispherical thin shell structure. This structure will produce a certain pressure deformation under the impact pressure. Due to the rigidity of the material, it can absorb and disperse the force, and the smooth surface and round curve can easily make the impact object slip away, thus reducing the impact time. According to needs and strengthening the strength of the helmet shell, the shell can be made into various types such as smooth top, top rib, edge and no edge.
(2) Hat lining: hat lining is the general term for the parts in the hat shell that are directly in contact with the top of the wearer's head. The material of the hat lining can be made of cotton webbing, synthetic fiber belt and plastic lining belt. The hat hoop is a ring-shaped belt that tightly surrounds the person's head when worn. The forehead part of the belt is lined with sweat-absorbing material, which has a certain sweat-absorbing effect. . There are two types of hat hoop ring belts: fixed belt and adjustable belt. There are two kinds of hat hoops with back collar and without back collar. The top belt is the lining belt that contacts the top of the human head. The top belt and the cap shell can be connected by rivets, or the socket of the belt can be connected with the socket of the cap shell. The top belt is in the shape of a cross or six strips. Correspondingly, there are 4 to 6 sockets.
(3) Chin strap: a strap tied to the chin to fix the helmet. The chin strap is composed of a strap and a locking clip. Liner without back collar, with "y" shaped chin strap.
Main technical requirements
1) General requirements
(1) The cap band can be adjusted according to the applicable head circumference size indicated on the helmet logo.
(2) The area of the hatband corresponding to the forehead should have sweat-absorbent fabric or a sweat-absorbent band. The width of the sweat-absorbent band should be greater than or equal to the width of the hatband.
(3) The laces should be made of soft textile fabric, with a belt with a width of not less than 10 mm or a rope with a diameter of not less than 5 mm.
(4) Materials that are toxic, harmful, or can easily cause skin allergies or are harmful to the human body must not be used.
(5) The aging resistance of the material should not be lower than the date indicated on the product label. The performance of a helmet in normal use should not be lower than the standard requirements due to material reasons during the period of use. All materials used should have a corresponding life expectancy.
(6) When the safety helmet is equipped with accessories, the stability of the safety helmet when worn normally should be ensured. Accessories should not affect the normal protective function of the helmet. (7) Quality: Ordinary safety helmet does not exceed 430g, cold-proof safety helmet does not exceed 600g
(8) Internal dimensions of the cap shell: length 195-250 mm; width 170-220 mm; height 120-150 mm,
(9) Visor: 10-70 mm.
(10) Cap grid: less than or equal to 70mm.
(11) Protrusions: The height of the protrusions between the inside of the cap shell and the cap lining shall not exceed 6mm, and the protrusions shall be covered with soft pads.
(12) Ventilation hole: When the cap shell has ventilation holes, the total area of the ventilation holes is 150-450 mm2
2)Basic technical performance
(1) Impact absorption performance. After being pre-treated by high temperature, low temperature, water immersion, and ultraviolet irradiation, the impact test shall be conducted. The force transmitted to the head mold shall not exceed 4900 N. The cap shell shall not have any fragments detached.
fall
(2) Puncture resistance. After being pre-treated by high temperature, low temperature, water immersion, and ultraviolet irradiation, the puncture test must be performed. The steel cone must not contact the surface of the head mold, and the cap shell must not have fragments falling off.
(3)The strength of the lower suburban zone. The force value when damage occurs in the lower suburbs should be 150-250N.
