GB1591712A - Helmets - Google Patents

Description

(54) IMPROVEMENTS IN AND RELATING TO HELMETS (71) We, SONIC HELMETS LIMITED, a British Company (formerly of 503 Coventry Road, Small Heath, Birmingham 10) and now of Communication Centre, 202 Bradford Road, Castle Bromwich, Birmingham, B39 9AA, 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: This invention relates to a helmets such as are used when, for example, motor cycling, power boating and mountaineering.

A prime consideration in the design of safety helmets is to provide good crash protection for the wearer's skull. This is usually achieved by forming a helmet from a substantially rigid outer shell and an inner lining of softer energy absorbing material to act as , a cushion between the shell and wearer's skull.

The ear regions of a skull are particularly sensitive and to protect these regions it is the practice to design the helmet to cover the ears. This applies both to open-face type helmets which cover the upper, rear and side portions of a skull, leaving the face uncovered, as well as to full-face helmets where a chin piece portion covers the wearer's chin and defines the lower part of a window-like viewing aperture.

An undesirable consequence of this protection is that the wearer's ability to hear sound signals clearly, whether from another person or radio, is severely impaired. This can be a particular disadvantage to wearers such as police motor-cyclists with whom it is desirable to achieve one or two-way radio communication, and is also a disadvantage to the motor cycling public who would appreciate being able to communicate with a fellow rider or receive radio transmissions.

A further problem which has been experienced hitherto is in providing a satisfactory microphone facility for giving an electrical signal in response to a helmet wearer's speech without undue interference from, for example, wind and engine noise.

It is one object of the present invention to provide a helmet which facilitates improved sound communication.

According to the present invention a helmet of the full-face type comprises a substantially rigid shell having a chin piece portion and a sound receiving transducer and a sound emitting transducer located inside said shell in the region of said chin piece portion.

Preferably said chin piece portion is provided with a lining layer of energy absorbing material.

The sound transducer(s) may be wholly or only partially embedded in a lining and the material of the lining may be moulded or otherwise arranged in direct contact with substantially the whole of the transducer or shaped to define a cavity for the transducer.

The transducer may be attached directly to the helmet shell or may be supported relative thereto by, for example, lining layer material.

The helmet may be provided with one or more transducers to emit sound and one or more to give an electrical output related to speech received from a helmet wearer.

A sound emitting transducer may be provided to respond to signals received from equipment such as a sound receiving transducer in another helmet, a radio, or a cassette player.

Signals may be communicated to a transducer either directly by an electrical conductor, by radio transmission, or by capacitive or inductive links.

The sound transducer(s) are preferably positioned near the centre of the chin piece portion where a relatively greater thickness of padding can be provided without any modification to the shape or dimensions of the main part of the helmet shell as may be necessary if a transducer were provided in an ear region. Thus good safety protection may still be provided.

To facilitate clear reception of sound within the helmet, especially when a sound emitting transducer is positioned in a central area of the chin piece portion, the invention provides in the helmet a sound duct extending from the transducer to assist in selective directioning of sound inside said helmet.

The duct may be formed by tubing positioned inside the rigid shell. The tubing may be embedded in lining layer material and preferably the tubing is resilient or readily deformable so as not to constitute a safety hazard.

Alternatively the duct may be a passage defined by the material of an energy absorbing or other lining layer.

The provision of a sound duct is particularly desirable to facilitate selective directioning of sound from a sound emitter, such as an earpiece or loudspeaker, to ear regions when the sound emitter is positioned remote from the ear regions of the helmet.

It can, however, also be desirable where a sound receiver, e.g., a microphone, is positioned away from the helmet wearer's mouth region and it is desired selectively to direct speech to the sound receiver.

Preferably ducting is selectively positioned to minimise sound feed-back which might occur between the emitter and receiver by virtue of the receiver detecting sound from the emitter in addition to speech from the helmet wearer.

Where two or more helmets each having a receiver and transmitter are interconnected to facilitate conversation between the wearers, it is particularly desirable to minimise any direct sound feed-back from the sound receiver to emitter of one helmet via the emitter and receiver respectively of another helmet. This may be achieved at least partially by the use of a sound duct or ducts in the helmets, but any further reduction in feed-back is advantageous in assisting in providing greater sound clarity.To provide improved two-way communication between two helmets there may be provided first and second amplifiers for amplifying signals, received respectively from sound receiving transducers positioned in said helmets, for transmission to sound emitting transducers positioned in said helmets, the first and second amplifiers being interconnected such that at least a portion of the output signal of each amplifier is fed to the input of the other amplifier at a phase substantially opposite to that of the signal received from a sound receiving transducer by said other amplifier.

Each amplifier may comprise a preamplifier unit and a power amplifier unit with a portion of the output of each power amplifier unit being fed to the input of the pre-amplifier unit of the other amplifier.

The resulting feed-back signal assists in reducing the sound feed-back in each of the helmets.

To guard against an excessive sound level being created by a sound emitting transducer an automatic gain control unit may be provided in an amplifier, typically between the pre-amplifier and power amplifier units.

The amplifiers may be housed together in a single package to which each helmet, and any external power supply, may be connected, or each helmet may incorporate an amplifier, preferably located in the chin piece portion of the helmet in the case of a full face type helmet. Alternatively more than one amplifier may be built into one helmet which may then act as a master helmet to which one or more slave helmets may be connected. A power supply may be located in a helmet.

In addition or alternative to automatic gain control in an amplifier, the sound volume in a helmet may be regulated by a volume control. The volume control may be provided on the helmet and preferably is of an irregular shape readily operable by a gloved hand.

Additionally or alternatively to the use of electrical feed-back between amplifiers to reduce sound feed-back, the present invention seeks to provide further means for assisting in reducing sound feed-back.

Two sound receiving transducers may be located within the helmet in the chin piece portion thereof and arranged such that one of said transducers is more sensitive than the other to sound generated by the helmet wearer.

Preferably two receiving transducers are located substantially alongside one another and preferably they are equally sensitive to unwanted sound emitted by a sound emitting transducer whilst one is more sensitive to wanted sound generated by the helmet wearer. By inter-connecting said receiving transducers in, for example, a back to back arrangement the effect of sound received from a sound emitting transducer in the helmet may be cancelled out such that there remains for amplification substantially only the signal from sound generated by the helmet wearer.

Automatic switching may be provided as appropriate to disconnect speech communication when receiving signals from a cassette or radio broadcast, and vice versa.

Several embodiments of the invention will be described, by way of example, with reference to the accompanying diagramatic drawing in which: Figure I shows diagramatically two helmets and apparatus in accordance with the present invention; Figure 2 shows in detail part of a helmet shown in Figure 1; Figure 3 is a view in the direction of arrow A of Figure 2; Figures 4 a, b, & c, show respectively elevation, plan, and end views of the sound emitting transducer and associated ducting of Figure 2; Figure 5 shows in detail the sound receiving transducer and associated ducting of Figure 2; Figure 6 shows amplifiers for interconnecting the two helmets of Figure 1; Figure 7 shows in detail a sound receiving transducer and ducting in accordance with another embodiment of the invention, and Figures 8 to 10 show details of electrical circuits for the transducer of Figure 7.

Two full face type helmets 10 in accordance with the present invention are illustrated in figures 1 to 3 interconnected by a power-pack and amplifier 11. Each helmet comprises a substantially rigid fibre-glass outer shell having formed integrally therewith a chin piece portion 12, and both this portion and the remainder of the helmet is lined with energy absorbing expanded polystyrene and cork 16 to cover the most sensitive parts of a head.

Each helmet comprises one sound receiving transducer 13, e.g. a microphone, located centrally across the chin piece portion 12 or near the lower edge 15 thereof, and two sound transmitting transducers 14, e.g., earpieces, located symetrically in the side regions of the chin piece portion.

The transducers are embedded in the lining material 16 and sound ducts 17 for selectively directioning sound extend within the lining from the sound emitting and receiving transducers to the ear and mouth regions of the helmet respectively. The ducts are moulded from rubber and shaped to extend around the transducers as illustrated by Figures 4 & 5.

For communication the two helmets 10 are electrically connected to the powerpack and amplifier 11 as illustrated schematically in Figure 6. From this figure it will be seen that the output from one sound receiving transducer 13 of one helmet is fed to a pre-amplifier unit 18, then through an automatic gain control and volume control 19, to a power amplifier unit 20, which serves to drive the two sound emitting transducers 14 of another helmet. The output of a power amplifier unit of one amplifier is fed to the pre-amplifier unit of the other amplifier.

Thus each pre-amplifier unit receives at inverting and non-inverting terminals the output from a power amplifier unit 20 and the output from a microphone 13. Sound feed-back between the loudspeakers and microphone in each helmet is thereby reduced.

In another modification of the apparatus shown in Figures 1 to 6, the sound receiving transducer may comprise two microphones 21, 22, as illustrated in Figure 7 and mountable centrally in the helmet chin piece portion side by side. One of the microphones 21 is more sensitive to the helmet wearer's speech by virtue of ducting 23 which selectively directs speech to that microphone, but both microphones are located side by side to be substantially equally sensitive to sound from the relatively distant sound emitting transducers.

By suitably connecting the two microphones the effect on the amplifiers of the feed-back of sound within the helmet from the sound emitters to the receivers may be reduced and a relatively greater clarity of communication achieved. Connection of the pairs of microphones may be in parallel in the case of opposite polarity microphones, with their outputs applied to a single input of a pre-amplifier unit as illustrated in Figure 8, or where the microphones are of like polarity their outputs may be applied respectively to inverting and non-inverting inputs of a pre-amplifier unit as illustrated in Figure 9.

Alternatively, as illustrated in Figure 10, the outputs of microphones 21, 22, may be applied respectively to the inverting and non-inverting inputs of two primary preamplifiers 24, 25, the combined output of which is applied to a further pre-amplifier unit 26.

To minimise interference from low frequency wind noise and high frequency engine noise such as prevail when motorcycling or power boating the amplifiers preferably have a greater gain over the frequency range 300 to 3,000 Hz. than outside said range.

Whilst the amplifiers have been shown and described specifically as each comprised of separate units interconnected together, a single multi-function component may be provided to replace two or more of the separate units, and this is particularly advantageous to reduce space where an amplifier package is incorporated in a helmet.

The amplifier 11 may conveniently be located, for example by the use of suction pads, on the body of a motor cycle where the communication aids are fitted to the helmets of motor cyclists.

WHAT WE CLAIM IS: 1. A helmet of the full face type comprising a substantially rigid shell having a chin piece portion and a sound receiving transducer and a sound emitting transducer located inside said shell in the region of said chin piece portion.

2. A helmet according to claim 1 wherein the chin piece portion is provided with a

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

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. Figure 2 shows in detail part of a helmet shown in Figure 1; Figure 3 is a view in the direction of arrow A of Figure 2; Figures 4 a, b, & c, show respectively elevation, plan, and end views of the sound emitting transducer and associated ducting of Figure 2; Figure 5 shows in detail the sound receiving transducer and associated ducting of Figure 2; Figure 6 shows amplifiers for interconnecting the two helmets of Figure 1; Figure 7 shows in detail a sound receiving transducer and ducting in accordance with another embodiment of the invention, and Figures 8 to 10 show details of electrical circuits for the transducer of Figure 7. Two full face type helmets 10 in accordance with the present invention are illustrated in figures 1 to 3 interconnected by a power-pack and amplifier 11. Each helmet comprises a substantially rigid fibre-glass outer shell having formed integrally therewith a chin piece portion 12, and both this portion and the remainder of the helmet is lined with energy absorbing expanded polystyrene and cork 16 to cover the most sensitive parts of a head. Each helmet comprises one sound receiving transducer 13, e.g. a microphone, located centrally across the chin piece portion 12 or near the lower edge 15 thereof, and two sound transmitting transducers 14, e.g., earpieces, located symetrically in the side regions of the chin piece portion. The transducers are embedded in the lining material 16 and sound ducts 17 for selectively directioning sound extend within the lining from the sound emitting and receiving transducers to the ear and mouth regions of the helmet respectively. The ducts are moulded from rubber and shaped to extend around the transducers as illustrated by Figures 4 & 5. For communication the two helmets 10 are electrically connected to the powerpack and amplifier 11 as illustrated schematically in Figure 6. From this figure it will be seen that the output from one sound receiving transducer 13 of one helmet is fed to a pre-amplifier unit 18, then through an automatic gain control and volume control 19, to a power amplifier unit 20, which serves to drive the two sound emitting transducers 14 of another helmet. The output of a power amplifier unit of one amplifier is fed to the pre-amplifier unit of the other amplifier. Thus each pre-amplifier unit receives at inverting and non-inverting terminals the output from a power amplifier unit 20 and the output from a microphone 13. Sound feed-back between the loudspeakers and microphone in each helmet is thereby reduced. In another modification of the apparatus shown in Figures 1 to 6, the sound receiving transducer may comprise two microphones 21, 22, as illustrated in Figure 7 and mountable centrally in the helmet chin piece portion side by side. One of the microphones 21 is more sensitive to the helmet wearer's speech by virtue of ducting 23 which selectively directs speech to that microphone, but both microphones are located side by side to be substantially equally sensitive to sound from the relatively distant sound emitting transducers. By suitably connecting the two microphones the effect on the amplifiers of the feed-back of sound within the helmet from the sound emitters to the receivers may be reduced and a relatively greater clarity of communication achieved. Connection of the pairs of microphones may be in parallel in the case of opposite polarity microphones, with their outputs applied to a single input of a pre-amplifier unit as illustrated in Figure 8, or where the microphones are of like polarity their outputs may be applied respectively to inverting and non-inverting inputs of a pre-amplifier unit as illustrated in Figure 9. Alternatively, as illustrated in Figure 10, the outputs of microphones 21, 22, may be applied respectively to the inverting and non-inverting inputs of two primary preamplifiers 24, 25, the combined output of which is applied to a further pre-amplifier unit 26. To minimise interference from low frequency wind noise and high frequency engine noise such as prevail when motorcycling or power boating the amplifiers preferably have a greater gain over the frequency range 300 to 3,000 Hz. than outside said range. Whilst the amplifiers have been shown and described specifically as each comprised of separate units interconnected together, a single multi-function component may be provided to replace two or more of the separate units, and this is particularly advantageous to reduce space where an amplifier package is incorporated in a helmet. The amplifier 11 may conveniently be located, for example by the use of suction pads, on the body of a motor cycle where the communication aids are fitted to the helmets of motor cyclists. WHAT WE CLAIM IS:

1. A helmet of the full face type comprising a substantially rigid shell having a chin piece portion and a sound receiving transducer and a sound emitting transducer located inside said shell in the region of said chin piece portion.

2. A helmet according to claim 1 wherein the chin piece portion is provided with a

lining layer in which at least one of said sound transducers is embedded.

3. A helmet according to claim 1 or claim 2 wherein two sound receiving transducers are located in the chin piece region and arranged such that one transducer is more sensitive than the other to sound emitted by a helmet wearer whilst both are equally sensitive to sound emitted by sound transducer(s) in the helmet.

4. A helmet according to any one of claims 1 to 3 wherein the helmet is provided with a lining layer and at least one of said transducers is supported relative to the outer shell by said lining layer.

5. A helmet according to any one of claims 1 to 4 wherein a duct is provided to assist selective directioning of sound within the helmet.

6. A helmet according to claim 5 wherein the duct is defined by material of a lining layer.

7. A helmet according to claim 5 wherein the duct is formed by tubing positioned inside said rigid shell.

8. A helmet according to claim 7 wherein the tubing is resilient.

9. A helmet according to claim 8 wherein the tubing is formed of moulded rubber and extends around a transducer.

10. A helmet according to any one of claims 5 to 9 wherein the duct extends from a sound emitting transducer towards an ear region of the helmet.

11. A helmet according to claim 10 wherein two sound emitting transducers are provided.

12. A helmet according to claim 11 wherein said two transducers are located symmetrically in the side regions of the chin piece portion.

13. A helmet according to any one of the preceeding claims wherein an amplifier is located in the chin piece portion of the helmet.

14. A helmet constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.