US3054111A

US3054111A - Shock absorbing helmet

Info

Publication number: US3054111A
Application number: US786810A
Authority: US
Inventors: Robert R Hornickel; Harry W Austin
Original assignee: Mine Safety Appliances Co
Current assignee: MSA Safety Inc
Priority date: 1959-01-14
Filing date: 1959-01-14
Publication date: 1962-09-18
Anticipated expiration: 1979-09-18

Description

Sept. 18, 1962 R. R. HORNICKEL ETAL SHOCK ABSORBING HELMET 2 Sheets-Sheet 1 Filed Jan. 14, 1959 INVENTORE) koazkr R. llomwcx'fz. :m/ 1711A BY flwwq, 1-,

p 1962 R. R. HORNICKEL ETAL 3,054,111

SHOCK ABSORBING HELMET Filed Jan. 14, 1959 2 Sheets-Sheet 2 INVENTORS Bi wd HARRY M asruv N' fla n, 5M v-m/ML Tbs/ AU or-ne s United States Fatent time 3,il54,l l l Patented Sept. 18, 1962 3,054,111 SHOCK ABSORBING HELMET Robert R. Hornickel and Harry W. Austin, Monroeville, Pa., assignors to Mine Safety Appliances Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 14, 1959, Ser. No. 786,810 6 Claims. (Cl. 2-3) This invention relates to protective helmets or safety hats, such as worn by miners and industrial Workers to protect their heads from falling objects, and more particularly to means for absorbing the shock of accidental impacts.

The conventional protective helmet or hard hat is held in position on the head by means of a suspension inside of it. The purpose of the suspension is to fit the helmet to the head and to space the head from the shell so that downward impacts against the shell will not be transmitted directly to the head. However, part of the impacting force is transferred to the head through the suspension, the rest being absorbed by the permanent distortion of parts of the helmet shell and suspension. The percent of impact force transferred to the head is a measure of the protective qualities of the helmet. Thus, the smaller the percentage of transferred force, the safer the helmet. This invention deals with means for building more energy absorption into helmets, particularly of the type in which head-engaging cradle straps support anchor lugs inserted in sockets in a helmet shell.

It is among the objects of this invention to provide a protective helmet, in which the suspension is easily removed and replaced, in which the suspension fasteners are extremely simple, in which the suspension serves as a real shock absorber, and in which shock absorbing means are located in sockets around the lower part of the helmet shell.

In accordance with this invention, a rigid helmet shell contains a head-receiving cradle that has head-engaging straps. The lower part of the inside of the shell is provided with circumferentially spaced sockets that extend upward. Disposed in the sockets are shock absorbing means, with which the lower ends of the straps are connected to support the shell. At least part of the shock absorbing means at each socket is permanently deformable if, in use, the downward pressure of the shell on the shock absorbing means exceeds a predetermined value when the shell receives a downward impact. The energy required to permanently deform the shock absorbing means is absorbed thereby so that the shock of the impact against the head is reduced. The shock absorbing means may consist solely of specially formed anchor lugs for the cradle straps, or of anchor lugs in combination with adjoining permanently deformable members.

The invention is illustrated in the accompanying drawings, in which FIG. 1 is a bottom or inside view rating our invention;

FIG. 2 is an enlarged longitudinal section taken on the line IIII of FIG. 1;

FIG. 3 is an enlarged inner side view of a cradle strap anchored in place in a modified embodiment of the invention, with part of the helmet shell broken away;

FIG. 4 is a vertical section taken on the line IV-IV of FIG. 3;

FIGS. 5 and 6 are views similar to FIG. 3 of two other embodiments of the invention;

FIG. 7 is a vertical section taken on the line VIIVII of FIG. 6; and

FIGS. 8, 9, 10 and 11 are vertical sections similar to FIG. 7 of four additional modifications of the invention.

Referring to FIGS. 1 and 2 of the drawings, the rigid shell of a protective helmet has a dome-shaped crown 1 of a helmet incorposurrounded at its bottom by an integral brim 2. Inside the shell there is a head-receiving cradle formed from straps 3 of any suitable material. These straps may cross each other at the top of the head, or they may have their upper ends joined by a lace 4 in order to make the cradle adjustable. Disposed inside the lower portion of the cradle and attached to the straps in any suit-able manner is the usual sweat band 5.

The lower ends of the cradle straps are looped through slots 7 in the lower part of strong anchor lugs 8 to connect the lugs and straps together permanently. Each lug may be a rectangular member which extends a short dis tance upward along the outside of the strap attached to it. It also projects laterally from opposite edges of the strap to form rectangular end portions. The lugs are detachably connected to the helmet shell by inserting them up into sockets molded into the lower part of the crown just above the brim. Thus, the shell is molded to provide it with a pair of laterally spaced, downwardly opening sockets 9 straddling the lower end of each strap. The adjacent sides of each pair of sockets also are open. The end portions of the lugs are inserted upwardly in the sockets to support the shell. The lugs in turn are sup* ported by the cradle straps fitting over the head of a wearer. The suspension can be removed quickly from the shell by merely pulling the lugs down out of the sockets.

It is a feature of this invention extend to the top of the sockets, in which the lugs are slidable vertically, but are spaced therefrom by blocks 10 of energy absorbing material, such as a crushable brittle material that is hard and strong enough to ofier considerable resistance to crushing, but which will break or collapse when enough force is applied to it and will not attempt to return to its original form. For this purpose an expanded brittle material can be used, such as cellular cellulose acetate or an expanded thermoplastic vinyl resin. Other suitable materials are foam glass, at crushable granular material, foamed plastics, balsa wood and other materials that deform permanently under pressure.

During normal use of the helmet the energy absorbing blocks 10 retain their shape and even are not deformed by blows of moderate force against the helmet. However, if the shell receives a downward impact exceeding a predetermined value considered dangerous to the head, the downward pressure on the shell causes it to press down against the blocks with so much force that they fail. That is, the blocks are crushed between the upper ends of the sockets and the anchor lugs. The energy required to crush the blocks in this manner is over and above that normally absorbed by the helmet shell and cradle straps. This excess energy is absorbed by the blocks and is therefore not transmitted through the cradle to the head. Consequently, the shock of the impact against the shell is greatly reduced before it can react against the head. The lugs and blocks constitute the shock absorbing means.

In the modification shown in FIGS. 3 and 4, the anchor lug 12 that attaches a cradle strap 13 to the shell 14 extends up to the top of the sockets 15; that is, the lug substantially fills the sockets. The end portions of the lugs are provided with a plurality of vertically spaced slots 16 that extend inward toward each other from the opposite ends of the lugs to form laterally extending tongues 17. The lug is slotted only part way down so that it will not be weakened unduly, and the slots extend inward to the central portion of the lug in the space between the two sockets. The upper tongues are strong enough to support the helmet shell during normal use, but under severe downward impact they and the underlying tongues will be bent or broken oif the main body of the lug. The energy that the lugs do not required to deform or break the tongues in this manner is absorbed and not transmitted to the head.

Another shock absorbing anchor lug is shown in FIG. 5. This lug 20 is the same height as the one just described, but most of its upper portion is cut away to form a large recess 21 between two thin legs 22 which engage the upper ends of the sockets 23 in the helmet shell 24. If the helmet is subjected to a severe blow, the downward pressure of the shell on these thin legs will deform or crush them. The energy consumed in crushing the legs is absorbed and not transmitted to the head.

In the modifiwtion shown in FIGS. 16 and 7, an anchor lug 26 of about the size of the one shown in FIG. 2 is illustrated. Like the first-described lugs, this one does not extend to the top of the sockets 27 in the helmet shell 28. Its outer upper edge, as shown in FIG. 7, engages a ledge 29 formed on the outer wall of the pair of sockets. The space above the lug is empty. When the shell is subjected to an impacting force of suflicient magnitude, the ledge will be forced down over the substantially stationary lug, which is thereby driven deeper into the slightly tapered upper ends of the sockets. Since the sockets above the ledge are narrower than the lug, any additional distance the lug is forced into the tapered sockets requires sufficient force to deform the helmet shell material out of its normal position. The energy required to move the lug farther into the sockets in this manner will be absorbed by the helmet and not transferred to the head of the wearer.

In the embodiment of the invention shown in FIG. 8, the sockets 31 are similar to the ones just described, except that they have no ledges. 'Ihe tapered anchor lug 32 fits snugly in the lower half of the sockets. Movement of the upper ends of the lug and sockets toward each other requires the exertion of enough force to deform the side walls of the socket. That force is absorbed by the system.

The anchor lug 35 shown in FIG. 9 is not tapered, but has an outwardly projecting lip 36 at its lower edge which normally engages the lower surface of the helmet shell brim 37. To force this lug farther into the sockets 38, sufficient downward pressure must be applied to the shell to deform the lip. The force required to do this is absorbed.

FIGS. and ll illustrate two metal anchor lugs that can be used for connecting the cradle straps to a helmet shell. The anchor 40 shown in FIG. 10 is provided with several reverse bends, and a cradle strap 41 extends through a slot 42 in the lower part of the anchor. Under sufficient impact on the helmet shell 43, the anchor will collapse in the sockets 44, but the energy required for that purpose will be absorbed by the anchor and not transmitted to the head. i

The metal anchor 45 shown in FIG. 11 has one continuous curve from top to bottom. Its upper and lower edges will be curled toward each other if the helmet shell 46 is forced down against the anchor with suflicient pressure. The energy required to thus deform the anchor is absorbed.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

. l. A protective helmet comprising a rigid shell, a head- 'receiving cradle in the shell spaced from the top thereof and having head-engaging straps, a headband in the cradle suspended from said straps, the lower part of the inside of the shell being provided with circumferentially spaced upwardly extending sockets having upper end walls i and inner and outer sidewalls, and a plurality of circumferentially spaced shock absorbing means inserted in the sockets in engagement with said upper end walls and removable from the lower ends of the sockets, the lower ends of said straps being connected with the lower part of said means to support the shell, and the upper part of said means inside each socket being permanently deformable therein in a vertical direction if in use the downward pressure of the shell on said means exceeds a predetermined value when the shell receives a downward impact, whereby the shock of said impact against the head will be reduced, the maximum extent of said deformation being less than the original distance between said cradle and the top of the helmet shell.

2. A protective helmet according to claim 1, in which said upper and lower parts of each shock absorbing means are integral with each other and form 3. lug on which the shell can move downward as it deforms said upper part.

3. A protective helmet according to claim 2, in which the upper part of each lug is formed as thin upright legs adapted to be deformed by said downward pressure.

4. A protective helmet according to claim 2, in which said sockets are arranged in circumferentially spaced pairs with the sockets in each pair spaced apart, each of said lugs being disposed in a pair of said sockets with the adjoining strap disposed between the sockets of that pair, said upper part of each lug being for-med as two groups of vertically spaced tongues projecting from opposite sides of a central portion between the sockets containing the lugs, and said tongues being adapted to be broken away from said central portion by said downward pressure.

5. A protective helmet according to claim 2, in which each lug is a vertically curved strip of metal adapted to be collapsed by said downward pressure.

6. A protective helmet comprising a rigid shell, a headreceiving cradle in the shell spaced from the top thereof and having head-engaging straps, a headband in the cradle suspended from said straps, the lower part of the inside of the shell being provided with circumferentially spaced upwardly extending sockets having closed tops and inner and outer sidewalls, and shock absorbing means in the sockets in engagement with said tops and removable from the bottom of the sockets, each of said means including an anchor lug and energy absorbing material spacing that lug from the top of its socket, the anchor lugs being independent of one another and connected to the lower ends of the straps and slidahle vertically in the sockets between said inner and outer sidewalls, and said material being one that will permanently deform vertically and absorb enough energy to fail and shorten if in use the downward pressure of the shell on said material exceeds a predetermined value when the shell receives a downward impact, whereby the shock of said impact against the head will be reduced, the maximum extent of said material P shortening being less than the original distance between said cradle and the top of the helmet shell.

References Cited in the file of this patent UNITED STATES PATENTS