GB1578352A - Protective helmet - Google Patents

Description

(54) PROTECTIVE HELMET (71) We, Du PONT CANADA INC. of P.O. Box 660, "Station A", Montreal, Quebec Canada H3C 2VI (formerly known as Du Pont of Canada Limited) a corporation of Canada, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a protective helmet and in particular to a helmet for the protection of sportsmen and/or workers in potentially hazardous occupations.

Helmets having a rigid or substantially rigid outer shell are used by sportsmen and workers involved in activities in which there is risk of injury to the head. For example, the use of such helmets may be compulsory or recommended protection in some sports, e.g.

football as played in North America, ice hockey, auto racing and the like, or occupations e.g. the construction industry. In ice hockey potentially serious or even fatal injuries can result from, for example, a puck or a hockey stick striking the head of a player or a player striking his head on the boards around the hockey rink or on the goal posts.

Similarly in the construction industry such injuries could result from falling objects.

The shape and design of protective helmets may vary according to the intended use of the protective helmet. In general, however, conventional protective helmets have a rigid or substantially rigid outer shell, cushioning means, for example, foam padding and/or straps, and frequently means, for example, chin straps, to attach the helmet to the user's head. In such helmets a major amount of the energy absorbed by the helmet on impact with an object is by virtue of the presence of the cushioning means inside the helmet.

While conventional protective helmets afford significant protection for the head of the user, such helmets are capable of improvement expecially with respect to the amount of energy that may be absorbed by the shell of the helmet.

Protective helmets having two shells are known. For example, a protective helmet having internal and external shells interconnected with VELCRO* strips is disclosed in U.S. Patent 3,413,656 of G. Vogliano and D.

Beckman, issued December 3, 1968. A helmet having two shells and adapted for circulation of air between the shells for cooling is disclosed in Canadian Patent 693,175 of R.F.

Denton, issued August 25, 1964.

A protective helmet having two shells adapted for the absorption of energy on impact with an object has now been found.

Accordingly the present invention provides a protective helmet comprising a protective head shell of thermoplastic material, said head shell having an inner section and an outer section, said outer section being superimposed on part of said inner section and being slidably connected to the inner section at at least two locations juxtaposed to the edge of the outer section, the outer section being spaced apart from the inner section away from said locations, said outer section being adapted to move relative to the inner section on impact of an object with said outer shell.

The present invention is illustrated by the embodiments in the drawings in which: Fig. 1 is a schematic representation of a protective helmet having two shells when viewed from the rear; and Fig. 2 is a schematic representation of a cross-section of the helmet of Fig. 1 along the line 2-2.

With reference to the drawings, Fig. 1 shows a protective helmet, generally indicated by 10, having an outer shell 11 and an inner shell 12. Outer shell 11 is superimposed on inner shell 12 and partially covers inner shell 12. As shown in the drawing outer shell 11 has two elongated orifices 13 near the outer edge of the shell. Pins 14 that are attached (not shown) to inner shell 12 project through elongated orifices 13 and slidably attach outer shell 11 to inner shell 12.

The protective helmet of Fig. 1 is shown in cross-section in Fig. 2. Outer shell 11 is superimposed on inner shell 12, being slidably attached to inner shell 12 by means of pins 14 *denotes trade mark.

through elongated orifices 13. Away from pins 14, outer shell 11 is spaced apart from inner shcll 12, forming space 15 therebetween.

When outer shell 11 is struck by an object, outer shell 11 is forced towards inner shell 12.

Air in space 15 acts as a cushion to absorb part of the energy of impact. In addition outer shell 11 moves relative to inner shell 12, such movement being facilitated by pins 14 in elongated orifices 13, thereby absorbing an additional part of the energy of impact.

Subsequently outer shell 11 will return to its original position.

Although not shown in Fig. 1 or Fig. 2 the protective helmet may have additional cushioning means e.g. foam pads and/or elastic straps located within the helmet for further absorption of energy. The helmet will normally also have support means, e.g. straps, adapted to position the helmet on a user's head. The helmet may also have attachment means, e.g. a chin strap, adapted to retain the helmet on the user's head.

One or both of outer shell 11 and inner shell 12 may have projections thereon directed towards the other shell. Alternatively projections on a separate base may be placed in space 15. Such projections, whether integral or on a separate base, may be of the type shown in our co-pending patent application No. 53178/76 (Serial No. 1,578,351) from which the present application has been divided out. The use of projections must be selective so as not to significantly hinder the relative movement of outer shell 11 with respect to inner shell 12 on impact of an object with outer shell 11.

The outer and inner shells of the protective helmet may be fabricated from the same or different polymers. Examples of polymers are poly-a-olefins e.g. polypropylene, homopolymers of ethylene and copolymers of ethylene and other a-olefins e.g. butene-l and vinyl acetate, and mixtures thereof; polyamides, especially polyhexamethylene adipamide and blends thereof with a compatible elastomeric or rubber material, polycarbonate, acrylonitrile/butadiene/styrene polymers; polyvinyl chloride; cellulose acetobutyrate; polybutylene terephthalate, polyoxymethylene polymers, polyester polymers reinforced with glass or KEVLAR* aramid fibres, and the like.In preferred embodiments the outer shell is fabricated from a polyethylene, or a blend of polyethylenes, having a density of at least 0 950 and a melt index in the range 1 to 12, especially 4 to 6, melt index being measured by the method of ASTM D1238 (Condition E), and the inner shell is fabricated from a similar polyethylene or a blend of 50-70%, by weight, of such a polyethylene and 30-50%, by weight, of an ethylene/vinyl aceate copolymer having 15 to 20% of vinyl acetate comonomer. Preferably the polymer is selected so that injection moulding techniques may be used in the manufacture of the helmets.

WHAT WE CLAIM IS:- 1. A protective helmet comprising a protective head shell of thermoplastic material, said head shell having an inner section and an outer section, said outer section being superimposed on part of said inner section and being slidably connected to the inner section at at least two locations juxtaposed to the edge of the outer section, the outer section being spaced apart from the inner section away from said locations, said outer section being adapted to move relative to the inner section on impact of an object with said outer shell.

2. The helmet of claim 1 in which there is support means to position said helmet on a user's head.

3. The helmet of claim 1 or claim 2, in which there is a chin strap adapted to retain the helmet on a user's head.

4. The helmet of any one of the preceding claims in which there is additional cushioning means selected from the group consisting of foam pads and elastic straps, and mixtures thereof.

5. The helmet of any one of the preceding claims in which the thermoplastic material of the inner shell and that of the outer shell are independently selected from the group consisting of poly-xl-olefins, polyamides, polycarbonate, acrylonitrile/butadiene/styrene polymers, polyvinyl chloride, cellulose acetobutyrate, polybutylene terephthalate, polyoxymethylene polymers and reinforced polyester polymers, said reinforced polymers being renforced with glass or aramid fibres.

6. The helmet of any one of claims 1 to 4 in which the thermoplastic material of the inner shell and that of the outer shell are independently selected from the group consisting of poly-a-olefins, polyamides and polycarbonate.

7. The protective helmet of any one of claims 1 to 6 in which at least one of the inner section and the outer section has projections thereon directed towards the other section.

8. The protective helmet of any one of claims 1 to 6 in which a further element comprising projections carried on a separate base is located between the two sections.

9. A protective helmet substantially as shown in the accompanying drawings and described herein with reference thereto.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. through elongated orifices 13. Away from pins 14, outer shell 11 is spaced apart from inner shcll 12, forming space 15 therebetween. When outer shell 11 is struck by an object, outer shell 11 is forced towards inner shell 12. Air in space 15 acts as a cushion to absorb part of the energy of impact. In addition outer shell 11 moves relative to inner shell 12, such movement being facilitated by pins 14 in elongated orifices 13, thereby absorbing an additional part of the energy of impact. Subsequently outer shell 11 will return to its original position. Although not shown in Fig. 1 or Fig. 2 the protective helmet may have additional cushioning means e.g. foam pads and/or elastic straps located within the helmet for further absorption of energy. The helmet will normally also have support means, e.g. straps, adapted to position the helmet on a user's head. The helmet may also have attachment means, e.g. a chin strap, adapted to retain the helmet on the user's head. One or both of outer shell 11 and inner shell 12 may have projections thereon directed towards the other shell. Alternatively projections on a separate base may be placed in space 15. Such projections, whether integral or on a separate base, may be of the type shown in our co-pending patent application No. 53178/76 (Serial No. 1,578,351) from which the present application has been divided out. The use of projections must be selective so as not to significantly hinder the relative movement of outer shell 11 with respect to inner shell 12 on impact of an object with outer shell 11. The outer and inner shells of the protective helmet may be fabricated from the same or different polymers. Examples of polymers are poly-a-olefins e.g. polypropylene, homopolymers of ethylene and copolymers of ethylene and other a-olefins e.g. butene-l and vinyl acetate, and mixtures thereof; polyamides, especially polyhexamethylene adipamide and blends thereof with a compatible elastomeric or rubber material, polycarbonate, acrylonitrile/butadiene/styrene polymers; polyvinyl chloride; cellulose acetobutyrate; polybutylene terephthalate, polyoxymethylene polymers, polyester polymers reinforced with glass or KEVLAR* aramid fibres, and the like.In preferred embodiments the outer shell is fabricated from a polyethylene, or a blend of polyethylenes, having a density of at least 0 950 and a melt index in the range 1 to 12, especially 4 to 6, melt index being measured by the method of ASTM D1238 (Condition E), and the inner shell is fabricated from a similar polyethylene or a blend of 50-70%, by weight, of such a polyethylene and 30-50%, by weight, of an ethylene/vinyl aceate copolymer having 15 to 20% of vinyl acetate comonomer. Preferably the polymer is selected so that injection moulding techniques may be used in the manufacture of the helmets. WHAT WE CLAIM IS:-

1. A protective helmet comprising a protective head shell of thermoplastic material, said head shell having an inner section and an outer section, said outer section being superimposed on part of said inner section and being slidably connected to the inner section at at least two locations juxtaposed to the edge of the outer section, the outer section being spaced apart from the inner section away from said locations, said outer section being adapted to move relative to the inner section on impact of an object with said outer shell.

2. The helmet of claim 1 in which there is support means to position said helmet on a user's head.

3. The helmet of claim 1 or claim 2, in which there is a chin strap adapted to retain the helmet on a user's head.

4. The helmet of any one of the preceding claims in which there is additional cushioning means selected from the group consisting of foam pads and elastic straps, and mixtures thereof.

5. The helmet of any one of the preceding claims in which the thermoplastic material of the inner shell and that of the outer shell are independently selected from the group consisting of poly-xl-olefins, polyamides, polycarbonate, acrylonitrile/butadiene/styrene polymers, polyvinyl chloride, cellulose acetobutyrate, polybutylene terephthalate, polyoxymethylene polymers and reinforced polyester polymers, said reinforced polymers being renforced with glass or aramid fibres.

6. The helmet of any one of claims 1 to 4 in which the thermoplastic material of the inner shell and that of the outer shell are independently selected from the group consisting of poly-a-olefins, polyamides and polycarbonate.

7. The protective helmet of any one of claims 1 to 6 in which at least one of the inner section and the outer section has projections thereon directed towards the other section.

8. The protective helmet of any one of claims 1 to 6 in which a further element comprising projections carried on a separate base is located between the two sections.

9. A protective helmet substantially as shown in the accompanying drawings and described herein with reference thereto.