GB2296855A - Apparatus for restraining injurious movements of the body - Google Patents

Abstract

The apparatus is incorporated in, or carried by, a user-associated article in the form of a safety harness, a safety helmet, a jacket or suit or other worn article, or in the form of a vehicle seat and/or of a head-rest of a vehicle seat. The apparatus comprised restraining means which act, or are displaceable or deployable to act, to avoid or minimise any harmful effects of localised accelerations and jerks of the neck and/or head and/or other parts of the body. In particular, the restraining means is designed to minimise whiplash and concussion effects. The means may be associated with a full body harness and be in the form of an inflatable collar (1, Figs. 1 and 2), an inflatable hood (6, Fig. 3) or an energy-absorbing, composite, tear-web and head support (8, 13, Figs. 6 to 9). Alternatively, an inflatable restraining means may be associated with a helmet (Figs. 10 to 12) or with the headrest of a vehicle seat (Fig. 17).

Description

SAFETY APPARATUS The present invention relates to safety apparatus for protecting a person in the event of a fall or any other accident by restraining injurious linear and angular accelerations of the head and neck so as to minimise whiplash and concussion effects.

Fall arresting or fall protection equipment provides safety for personnel who because of operational necessity have to work at heights and who may accidentally fall.

Fall arresting systems usually comprise a safety harness (a device very similar to a parachute harness which envelops and grips the body with joined textile straps), a fall arrester (a device for restraining or retarding the motion of a falling person), an anchorage (a device to allow attachment of the fall arresting system to the structure in the work area), and various connectors (devices such as small gated hooks or mountaineering style karabiners to connect the above system pieces together).

Whilst there has been some effort to design and develop better safety harnesses, significantly more effort has been expended in advancing fall arrester technology. Fall arresters retard the motion of a falling person by dissipating the faller's kinetic and potential energy generated by the fall and restrain the motion of a person in a similar controlled fashion to that of an inertia reel seat belt in a vehicle accident.

The faller consequently experiences a level of retarding force over a small period of time, of magnitude not beyond the estimated maximum threshold endurable by a human being. Whilst this affords good protection to the faller by virtue of a controlled retardation force or arrest force, it is the safety harness that gives the ultimate protection to the body of the faller.

There are generally three types of safety harnesses available in the fall arresting or fall protection ("FP") market, the waist belt type, the chest type and the full body harness ("FBH") type. It has been generally accepted that the "FBH" is the safest according to published tests, papers and data. It has shoulder, waist, pelvic and thigh straps integrated in its design. The chest type harness has only shoulder, thoracic and waist straps, whilst the waist belt type has only effectively one wide strap which fits around the waist region. Both of these latter types impart higher levels of trauma to the human body upon fall retardation by virtue of their strap number1 arrangement and transmission of force to the body.Excessive strap slippage can occur which has been shown to cause the release of the faller from particular chest harness types, and in the case of the waist belt type, extreme jackknifing to the body of the faller occurs, which can result with internal injury. Further, the fall victim is inadequately supported after the fall as he/she remains suspended awaiting post-fall rescue.

Alternatively, use of a FBH ensures the retarding force is applied to the body skeletal structure via a number of straps, with the minimum of strap slippage, and postfall rescue is greatly facilitated.

Traditionally full body harnesses designed for fall arresting use have been adopted or modelled on parachute harness designs. This has provided an excellent and logical starting point for design of FBHs, since the two applications appear similar.

Parachute harnesses envelop the body with a system of joined textile straps arranged such that dynamic forces imparted to the human body during free fall and parachute deployment are distributed over the body in a way that avoids localised injury, and the body remains contained and attached to the parachute system.

When a parachute is deployed in a descent the retardation forces are typically imparted to the parachutist via four main straps attached in the shoulder area of the harness. The free fall and subsequent retardation is relatively under control, (the parachutist is expectant and anticipative), and it generally occurs entirely in the vertical plane only.

Also parachutists tend to be very fit medically, (either escaping aircrew, combatants, or sports people).

A faller in a FBH has a similar experience during a fall arrest to that of a parachutist deploying his/her parachute, but with some important differences.

When a person accidentally falls from a height, there is no control over the descent which may be very haphazard and may involve multiple direct and partial collisions with protruding objects such that may be found in any industrial environment where falls present a hazard.

Certainly the faller will not be expecting the fall and will be completely disorientated during the fall. The resulting flailing, twisting and tumbling motion of the fall will be in several planes during that time. In contrast to the typical parachutist, industrial workers exposed to the risk of falling are not always in their peak of medical fitness, and may not be so resistant to any arrest forces imposed on them as a result of the action of the FP system.

As mentioned, known FP systems contain a fall arrester which itself contains a braking mechanism, which when activated provides an upward retarding force to arrest the faller. Consequently the faller is stopped completely before hitting the ground or other prominent and substantive platform. In contrast whilst a parachutist experiences an upward retardation upon parachute deployment, he/she is not brought to a complete stop but instead experiences a controlled and constant descent, only stopped by the ground, and not by the parachute system itself.

Known FP systems are connected to full body harnesses (FBHs) at a single harness attachment point ("HAP"), which can be dorsal (at the upper back), thoracic (near the sternum), or side. Such positions are often dictated by the working task, ergonomics and other factors, but generally there is only one such point whereas known parachute harnesses have typically four, in the shoulder/upper back area.

It is generally accepted through research that the safest harness attachment point is the dorsal type, because of the relative stability achievable during the fall, whether feet or head first and because the human body is more able to withstand the arrest forces imposed anatomically. However it is not always possible to use the dorsal harness attachment point, e.g. when climbing an installed ladder, because of ergonomics, and an alternative HAP such as the thoracic position can be used.

One of the main points discovered in accidental fall arresting circumstances is that the faller in an FBH experiences a significantly more hazardous and traumatic event than the parachutist jumping from an aircraft and deploying a parachute. It therefore could be argued that a parachute harness is not suitable for a basis of fall arresting FBH design as originally purported, because of the reasons mentioned above.

However, it remains a fact that such a basis was generally accepted by standards and legislative bodies internationally. The same is very much the case today, with very few real advances made in fall arresting FBH technology. Some comfort and ergonomic improvements have been made, i.e. aimed at the making the FBH more comfortable and usable for it's wearer.

However, in accepting the parachute harness design as a basis for FBH design and concentrating on comfort and ergonomics, the inventor believes that FBH designers have overlooked the intrinsic emergency requirements of the FBH. The inventor has realised from viewing slow motion playback of high speed film of simulated fall accidents involving fall arresting systems with an anthropometric dummy wearing a FBH in place of a human faller, it can be quite plainly seen during the arrest phase that whilst the body of the dummy is contained, the arms, legs and head all flail around at random, depending upon the attitude of the dummy at the point of falling, and upon the harness attachment position. Whilst the aim of all protective equipment is to protect, if in a fall accident a person was saved but broke a leg or arm, the injury would probably be regarded as being "unfortunate but acceptable given the circumstances" compared to the potential outcome without the equipment, i.e. death or permanent maiming.

Whilst arms and legs may be thus sacrificial, heads are certainly not. The inventor is very concerned at the amount of head flailing and jerking that can be observed in such simulations, and it can be most forcibly argued that known FBH do not protect the neck/head in a fall accident, and of course the neck and head contain vital organs, the brain and spinal cord.

As such, fallers might experience whiplash and/or concussion injury whilst wearing current known FBHs.

Whiplash is the sudden flexion - extension of the neck and flinging of the head that results for example from a typical rear-end vehicle collision. Concussion is used to name that state of sudden traumatic unconsciousness attended by retrograde and post-traumatic amnesia following the shaking of the brain in the skull from impact or acceleration. Medically, the brain, the muscles, spinal column, vessels and nerves in the neck can be damaged during excessive unrestrained jerking of the head which can lead to permanent injury.

It is the inventor's surmise that because a parachute harness does not need to provide protection against whiplash and concussion injury, when it's basic design was utilised for fall arresting purposes, then such deficiency was not recognised.

Further, by technical standard or by regulation, the maximum permitted arrest force during formal design approval testing is virtually always measured at the harness attachment point or at the anchorage. This is for practical test purposes and it does not measure localised accelerations and jerk on the dummy (simulating a faller's body) as it flails, twists, and jackknifes during a fall. (Jerk here meaning the rate of change of acceleration with respect to time). Some of these localised accelerations and jerks may be beyond endurable limits, and may cause secondary or primary injuries, such as whiplash and concussion. They are not presently measured, so the inventor surmises that such remain unknown.Certainly a significant number of technical standards just specify a connected solid torso shaped mass to simulate the faller, so any undesirable or hazardous characteristics of a FBH may go undetected.

Whiplash injuries first became known about to the general public as a result of vehicle accidents.

Rapid jerking of the neck and resulting injuries due to inertial changes in vehicle collisions led to a requirement to fit head restraints to vehicle seats.

In vehicle accidents a seat belt in the vehicle will stop the occupant from colliding with the vehicle interior during an accident. However whilst the legs, pelvis and torso are contained, the upper chest and particularly the head get very close, and in some circumstances do impact the vehicle interior. Such observed deficiencies in vehicle safety led to amongst other ideas the development of inertially activated gas deployed airbags, designed to cushion such an impact to the upper chest and head.

It is an object of the present invention to provide means to avoid or minimise any harmful effects of such localised accelerations and jerks in the important regions of neck and head and/or other parts of the body. Where protection of the neck is involved, the protection means may, for example, be incorporated in a safety harness, in a safety helmet, in a jacket or suit or in a seat and/or seat head-rest of a vehicle such as a car.

According to the present invention there is provided safety apparatus incorporated in or carried by a user - associated item comprising safety harness, a safety helmet, a jacket or suit or other worn article or as deployable means of a vehicle seat and/or a seat head-rest of a vehicle comprising restraining means which act or are displaceable to act to avoid or minimise any harmful effects of localised accelerations and jerks in the neck and/or head and/or other parts of the body.

Also according to the present invention an apparatus, for protecting the rear head and/or rear neck region of a person from the affects of injurious accelerations and jerks comprises at least one inflatable means carried by or forming part of an article which is to be worn by the person to be protected or to be juxtaposed said person, a source of pressurised gas or means for receiving such and communicating or communicatable with said inflatable means, and an inertia switch or jerk sensing/responsive means for permitting pressurised gas to flow from said gas source or receiving means to said inflatable means, said inflatable means being located on said article such that in the normal position of use and juxtaposition and upon inflation, the inflatable means inflates to provide support and/or restraining protection to the head and/or neck to prevent or inhibit undesired rearward movement of the head. It will be appreciated that on a preferred embodiment, such an inflatable means can be located in or on a vehicle driver or occupants seat, possibly in the region of the head rest/restraint, to counteract "whiplash".

In one broad aspect of the present invention a safety apparatus for protecting a user in the event of a fall comprises a suspension harness for connection to a fall arresting system and having restraining means for protectively restraining harmful movement of at least the neck or head of the user in the event of an accidental fall.

Preferably the restraining means comprises at least one inflatable means for providing supporting and/or restraining protection, and preferably a source of pressurised gas or means for receiving such and communicating with said inflatable means and an inertia switch or jerk sensing/responsive means or other sensing and operating/activating means for permitting pressurised gas to flow from said gas source or receiving means to said inflatable means.

The inflatable means is preferably for restraining/supporting at least the neck region and preferably a neckbag which is a small collar shaped inflatable bag preferably incorporated into the upper assembly of fall protecting harness. Once deployed the neckbag is used to restrain the jerking of the head and neck to protect a faller against whiplash and/or concussion injury during a fall, and can also give secondary protection from collisions with structural projections during the unpredictable tumbling in a fall.

A collapsed and gathered neckbag is preferably integrated into the shoulder region of the harness e.g.

a full body harness (FBH) in a similar fashion to that of a hidden hood in a rain jacket. This subscribes to good ergonomics and aesthetics. During the freefall or arrest phase a sensing mechanism, possibly an inertia switch, (similar to an aircraft crash switch which shuts down dangerous systems and activates emergency systems in an aircraft crash) will activate a valve on a miniature compressed gas bottle. The energy in the gas then inflates the neckbag.

In one embodiment of the invention, the inflatable means in the form of a neckbag is so designed that when inflated it envelops the cheeks, neck and chin area of the wearer to restrain that part of the body, rather like a medical immobilising collar. Some movement is preferably allowed, since perfect rigidity is not needed, nor is it desirable. Careful design considerations have to be applied so as to avoid injuries being induced by the neckbag itself.

In another embodiment of the invention, the neckbag is made as to envelop the whole of the back of the head like a hood, to give even more protection this would be a larger assembly than the previous embodiment.

As a further development of the invention other inflatable bags are used in various pressure contact points on the harness preferably FBH, (where harness straps grip the faller's body, for example the groin area) to avoid secondary fall injuries like bruising, circulatory restrictions, and abrasive impacts.

An alternative to the previously described preferred restraining means in the form of a neckbag is the use of a permanent head restraint. Thus also according to the present invention a suspension harness also includes neck and/or head restraint means which is in a permanently disposed or deployed condition or may be extendable or raisable or otherwise deployable, e.g.

by being telescopic, instead of being inflatable.

However, in practice this might prove too cumbersome in terms of weight, interfering with head movements during the work task, and it might detract from the equipment aesthetics which are important from a safety psychology viewpoint.

In all of the embodiments relating to a safety suspension harness or as a separate harness arrangement according to the invention, a connecting lanyard such as a rope, chain, wire or cable, is provided connectable at one end to a support structure and at the other end to the harness preferably via the HAP (p.4). Preferably the harness will include energy absorbing means which will preferably be provided as part of the HAP.In a preferred embodiment, the energy absorbing means comprises a strip, flap or other partially separable portion non-releasably secured in one region to the harness and in another region having an attachment member to which the lanyard is connectable whilst on the intermediate region said partially separable portion is adhered, bonded or preferably stitched to the harness such that when a fall occurs, the stitches will be broken to release said portion and to absorb energy thereby. A similar stitching arrangement is used in conjunction with parachutes to retard the descent of bombs dropped from aircraft. The partially separable portion is preferably arranged, shaped and dimensioned, e.g. as a triangular flap, to also act to support the back of the head when partially ripped away from the harness.

After a fall, for reasons of comfort the bag or bags (inflatable means) may be deflated manually by the suspended faller (if conscious) whilst awaiting rescue.

The exhaust gas from such an action can, if desired, be used to power a miniature siren provided for such purpose and integrated into the FBH. This could be used to alert people to the accident, rather like a personal alarm.

Whilst the costs of a typical harness e.g. an FBH, might increase as a result of this major development, it sets a new standard for safety and gives significantly increased value and could have a major impact in the industry.

The weight of the harness e.g. FBH, would increase although it is debatable as to its significance. Other areas could be reduced to compensate - buckles and straps - reduction in number, weight, strength, change in material and design.

In summary, significant resources have been expended upon fall protection systems whose function it is to dissipate the energy generated during a fall, such that the faller experiences a level of force over a small period of time, and that it's magnitude is not beyond the estimated maximum threshold endurable by a human being. However, harness and full body harness design has been neglected, and it is particularly these that ultimately protect the faller, not the fall arresting system. Also current standard test methods do not measure nor assess localised accelerations on the body as it unpredictably flails, twists, and tumbles during a fall, some of which forces created may be beyond endurable limits, and may cause secondary or primary injuries, such as whiplash of the neck and cerebral concussion.The present invention is intended to provide means to restrain such localised acceleration and jerk in the important regions of neck and head preferably by using an inertially activated gas deployed neckbag.

It is to be appreciated that the inflatable restraining means may comprise a safety device on its own or be securable to an existing harness as an adaption or be securable to a safety helmet or hat ("hard hat") or incorporated or be securable to a safety helmet such as that of a motor cyclist or be incorporated therewith together with the appropriate pressurised gas source or means for receiving such and an appropriate sensing and activation means.

Also according to the present invention, there is provided safety apparatus comprising an inflatable collar or other inflatable means securable to the user or securable to a suspension harness therefor or securable to a protective hard hat or helmet or incorporated therewith, a pressurised gas source or means for receiving such and in gas ducting communication with said collar or other restraining means, and acceleration or change of acceleration sensing means, such as an inertia switch, for enabling gas to flow from said source or receiving means to said collar and/or other restraining means to inflate such.

The inflatable means, gas source or receiving means and sensing means may alternatively be incorporated in other safety equipment such as a jacket for motor cyclists for other purposes such as padding protection or even as a head buoyancy aid where the sensing means may be replaced by known buoyancy aid activation means.

Instead of interia or jerk securing means or at least the equivalent thereof may be provided, for example, an air pressure sensitive means or a photocell which becomes exposed when a pull or jerk is experienced or a drop counter propeller as used on bombs or a like device.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic partial elevation of a user wearing safety apparatus including a suspension harness with connection to a suspension line of a fall arresting system and having a safety device including inflatable means in the form of a collar or neckbag and according to the invention; Fig. 2 is the same view as Fig. 1 but with the neckbag of the safety device inflated; Fig. 3 is a partial elevation similar to Figs. 1 and 2 but of a modified embodiment where the neckbag is extended to envelop at least the whole of the back of the head; Fig. 4 is a perspective view of a worker in a typical elevated situation wearing safety apparatus according to the invention comprising a full body harness including an inflatable neckbag;; Fig. 5 is a view of an accident situation of a worker wearing a harness according to an embodiment of the invention having energy absorbing means as a stitched triangular flap or "tear-web"; Figs. 6, 7 and 8 are fragmentary plan views of the worker and various stages of deployment of the "tear-web"; Fig. 9 is a fragmentary side elevation of the tear-web after utilisation thereof; Fig. 10 is a schematic perspective view of a person wearing a safety helmet or "hard hat" incorporating an inflatable restraining means, a source of pressurised gas or means for receiving such (not shown) and inertia sensing means (not shown) and forming a further embodiment of the invention; Fig. 11 is a view similar to Fig. 10 after inflation of the restraining means; Fig. 12 is a plan view of Fig. 11;; Fig. 13-16 schematically illustrate the body movements of a vehicle driver when struck from the rear and the "whiplash" effects and the inadequacy of known safety devices; and Fig. 14 is a schematic illustration of a vehicle seat with an inflatable safety device forming an embodiment of the invention.

The safety apparatus illustrated schematically in Figs. 1 and 2 comprises a full body harness with only part thereof, straps 2 being shown, having an undeployed inflatable neckbag or collar 1 secured thereto and being shown in Fig. 1 in the deflated condition. A connecting lanyard or other tie or connection means 3' of a full arresting system (not shown) is connected to an anchor point 3 on the harness 2. A miniature gas bottle as a source of pressurised gas and an inertia switch assembly indicated generally by 4 is secured at the rear of the harness and communicates so as in use to inflate neckbag 1 to the deployed condition 5 shown in Fig. 2.

In Fig. 4, the apparatus of Figs. 1 and 2 is modified by the inflatable means (1,6) being in the form of a hood bag shown deflated by broken lines 1 and inflated by full lines 6 and provides greater protection for the head.

Various modifications, as mentioned, may be made without departing from the scope of the present invention. For example, the neckbag or hood bag, the inflation means and sensing means may be provided as a discrete safety device or be attachable to an existing harness or protective hat or safety helmet or other user related item. Much of the technology developed for automotive airbags may be adapted or utilised in the apparatus of the invention especially the inflation and sensing means. The sensing means instead of being an acceleration or jerk sensing means such as an inertia type switch or like, may be a tension sensing device, such as a load cell, in the lanyard/tie anchorage or connection means.

In the embodiment schematically illustrated in Figs. 5 to 9, an alternative form of head restraint or restraining means for a safety harness 7. In normal use the restraint which is a triangular shaped flap 8, is stowed, i.e. stitched to the harness and is part of the harness and such as not to interfere with the wearer 9. If the harness wearer 9 falls the action of the tension in the safety lanyard 10 deploys the head restraint 8, giving some measure of protection to the head and neck. Figs. 5 to 9 describe the sequence of events.

Fig. 5 shows a typical accident in which a worker 9 has fallen from a ledge whilst carrying out his duties. He is wearing fall arrest equipment that will limit his fall. This comprises of a full body harness 7 which is connected via a HAP to a safety lanyard 10 which in turn is safely attached to the building. The safety lanyard 10 has means of energy dissipation to limit the arrest forces on the faller. At this point in time the faller is in free fall, (under the influence of gravitation alone), hence the safety lanyard 10 is slack.

Fig. 6 shows the rear of the faller at the same point in time. As explained above the safety lanyard 10 is slack due to the free fall. It is connected to the safety harness 7 by a metal "D" fitting which itself is attached to the strap system 7 enveloping the person 10.

A panel 12 is a connection point for all of the rear harness straps 7 - two of which are the shoulder straps 7.

The shaded triangular or panel area 13 under the head of the faller represents the stowed head restraint 13. This is attached to the two shoulder straps 7' and lies flat against the back. The shoulder straps 7' are composite assemblies made up of strips of normal webbing that has been attached to a special material known commercially as "tear-web". Tear-web is designed to tear apart into two strips under the action of a rated constant force. In so doing it dissipates the applied energy in a controlled manner.

Fig. 7 shows the rear of the faller again, but the fall has now progressed to the arrest phase. Here, all the slack in the lanyard 10 has been taken up and the resulting tension is starting to arrest the faller and therefore limit his fall. The lanyard 10 tension continues to increase until the rated tear force of the tear-web is reached. At this point the composite web, represented by the dotted area, starts to tear. In tearing it dissipates fall energy gained by the faller, it governs the forces, and it governs the speed at which the triangular head restraint 8 deploys.

Since the head restraint 8 is attached to the composite shoulder straps 7' it deploys simultaneously with the tearing of the tear-web and is raised to start covering the back of the neck. In tearing, the composite web separates into two strips 14, 14'. The upper strip 14 is pulled upwards by the tension in the lanyard 10 and the lower strip 14' is held against the back of the faller 10 by the rest of the strap system 7.

Fig. 8 shows the rear of the faller again at the end of the arrested fall. Fig. 9 shows the side view of the faller at the same point in time. The head restraint 8 is fully deployed and the composite web 14,14' is fully torn. This prevents the head 9' from being swung violently backwards, the main cause of whiplash injury. Depending upon the compliance of the material used for the restraint, there will be some measure of sideways cushioning protection for the head 9'.

In this arrangement the fall forces will be transmitted to the shoulder areas of the faller, which anatomically is much better than the single dorsal point normally associated with fall arrest harnesses. Instead of inertia sensing means, after equivalent means may be provided and such might alternatively be referred to as "activation means" which might comprise a photoelectric device exposable in requisite circumstances or a pressure sensitive means. Either of these sensors could be sandwiched between a small patch (the "rip patch") of tear web mounted to the harness. (The tear web is described under the extending head restraint). The sensor in each case would be activated by the tearing of the tear web, so either exposing the photoelectric cell or pressure pad. In the former case the presence of daylight would be registered on the cell, causing the initiation signal to be sent.In the latter case the presence of atmospheric pressure would be registered, causing initiation.

An inflatable bag may also be used with the harness of this embodiment but is not illustrated.

In the embodiment of Figs. 10-12, the invention provides a means to minimise whiplash and/or concussion injury, which can be suffered by persons who in the course of their activities place themselves at risk to injuries sustained by impact, or by experiencing sudden changes in acceleration. Such changes can be applied to different points of the body at different times and can cause hyperextension or hyperflexion ("whipping") of the unsupported neck, or in some cases, actual brain damage.

The embodiment comprises a helmet 16, a helmet mounted gas bag 17, which is normally deflated and is stowed in the safety or crash helmet 16 of the wearer 18. If the helmet wearer 18 is subjected to an impact of sufficient magnitude the gas bag 17 inflates rapidly to restrain the head from being whipped backwards, thus preventing whiplash injury.

Specifically then, the hat or helmet of this embodiment is to provide protection for safety or crash helmet wearers. Such categories of persons can include: (i) Persons who work at height and wear fall arrest safety harnesses, but who also wear climbing or generally safety helmets (ii) Racing car drivers (iii) Motor cyclists (iv) Aircrew. In particularly military aircrew, whose protective helmets by specification are relatively heavy, and therefore whose combined head and helmet weight would make them more prone to sustaining a whiplash injury (v) Rock climbers.

Figs. 10 and 11 illustrate the operational sequence of events: Fig. 10 shows a motorcyclist wearing a crash helmet 16. The stowed gas bag 17 is shown as a shaded area.

In Fig. 11 as a result of the motorcyclist 18 colliding with an object such as a motor vehicle, or falling off the motorcycle, a body mounted acceleration sensor (not shown) initiates the inflation of the head restraint 9 (17) when the acceleration of the body reaches a predetermined value. This allows the head restraint 19 to accommodate the normal posture of the head and neck by inflating to a horseshoe form. It also bears down upon the shoulders to give sideways support.

Fig. 12 is a view of the helmet etc., of Fig. 11 but from above. The helmet 16 is shown as is the horseshoe form of the inflated gas bag (19,17) shaded.

The embodiment of Fig. 14 is included to minimise whiplash injury, which can be suffered by motor vehicle occupants when involved with an accidental collision. Whiplash injury occurs predominantly in situations where a stationary vehicle is impacted at the rear by a moving vehicle. Whilst head restraints have been fitted to vehicle seats to prevent whiplash injury for some time, there is considerable medical evidence to show that they are not effective in their function.

The embodiment comprises a gas bag (21) which is normally deflated and stowed in the head restraint housing (22) of the vehicle seat 23. If the occupant 24 of the vehicle 25 is subjected to a rear end collision, the inertia sensor control (not shown) of the gas bag 21 causes such to inflate rapidly to restrain the head 24' from being whipped backwards, thus preventing whiplash injury. Figs. 13 to 16 illustrate the sequence of events: Fig. 13 shows a vehicle driver 24 whose vehicle 25 is stationary. Typically this could be at traffic lights, waiting at a junction or roundabout. The driver 24 is wearing an inertia reel seat belt (26). The seat 23 is fitted with a fixed head restraint 27.

In Fig. 14, the vehicle 25 has been struck by a moving vehicle from the rear. The vehicle body reaches its peak acceleration before the occupant's head and upper torso have accelerated a significant amount. The hip, shoulder then head reach their peak accelerations in turn, at different instants in time. The head has only the flexible and somewhat extensible neck through which the forces of acceleration of the torso may be transmitted. The delay in acceleration of the upper torso with respect to the acceleration of the car body is further amplified as these forces are transmitted to the head through the neck so that the head has even a shorter time to overcome the pronounced velocity differential which has developed. This could only be accomplished if a greater rate of acceleration were imparted to the head.

As a result the driver's torso begins to accelerate, pivoting about the hip pivot (Hp). This causes the seat belt webbing to be pulled out of the inertia reel mechanism. This in effect leaves the head behind as it pivots about the neck pivot (Hn) it is the writer's surmise that the head is allowed to pivot because the head restraint, which is fixed, cannot move in concert with the head, and so a gap develops, the "whiplash gap" (dimension W). The angle between the driver's head and body (angle A) reduces, causing concertinaing, and whiplash injury begins to occur.

Fig. 15 illustrates the incident some instants later. Here, the torso has pivoted further and has caused the inertia reel seat belt to activate and "lock up", preventing any further movement. The result of this is that dimension W has increased to W1, allowing the neck to concertina even further, and angle A reduces even more to angle A1. The flexing of the neck at this point causes the severest whiplash injury.

Fig. 16 illustrates the incident a few instants later. With the seat belt webbing now locked, the head has the time to reduce the velocity differential and "catch up" with the rest of the body. The angle A increases to A2 and the body assumes a more normal posture.

In Fig. 17 the embodiment of the invention is illustrated wherein the seat's fixed head restraint has been replaced with an Inflating Head Restraint, 21,22.

Fig. 17 represents the previous incident, but demonstrates that the inflating head restraint does not let the whiplash gap develop, nor does it allow the neck to concertina (as compared to Figs. 14 and 15). The body maintains a normal posture and whiplash injury is minimised.

An acceleration sensor (not shown) initiates the inflation of the inflatable part 21 of the head restraint 22, when the acceleration of the car body reaches a predetermined value. This allows the head restraint to accommodate the normal posture of the head and neck by inflating to a horseshoe form. A suitable source of pressurised gas and receiving and ducting means (not shown) will be provided. The operational details and mechanics may draw much from existing technology in this respect and thus need not be discounted in detail.

In considering this problem, the inventor has shown the best circumstance in Fig. 13, that is the driver is sitting in a correct posture, with the head restraint virtually touching the back of the head. This in theory will keep any whiplash gap to a minimum, but conversely, the normal gap between head and restraint should not be too small, or else discomfort or distraction may result during driving. However, should a driver sit more erect than that shown in Fig. 13 without adjusting the seat angle to suit, then the whiplash gap may become larger during an accident, which could create a more severe injury.

Whilst there have been some improvements to conventional fixed head restraint design, in terms of adjustment, they rely on the driver to ensure that the restraint is set correctly prior to setting out on a journey. Even so, a whiplash gap can still develop during an accident, because of the basic problem that the restraint cannot move to prevent the driver's head from being whipped backwards. However the present invention is designed to automatically fill any whiplash gap, thereby minimising the amount of whip.

Instead of part of the head restraint, the inflatable means at least may be attachable to the head restraint and/or vehicle seat or form part of the vehicle seat of even the occupants apparel or in any location or mounting to restrain whiplash effect.

Claims (23)

1. Safety apparatus incorporated in or carried by a user-associated article in the form of a safety harness, a safety helmet, a jacket or suit or other worn article, or in the form of a vehicle seat and/or of a head-rest of a vehicle seat, said apparatus comprising restraining means which act to or are displaceable or deployable to act to avoid or minimise any harmful effects of localised accelerations and jerks of the neck and/or head and/or other parts of the body.

2. Apparatus as claimed in claim 1, in which the restraining means is an inflatable bag operable to restrain at least rearward movement of the head, and in which means for enabling inflation of the bag in the event of an accident are provided.

3. A safety apparatus for protecting a user in the event of a fall comprises a suspension harness for connection to a fall arresting system and having restraining means for protectively restraining harmful movement of at least the neck or head of the user in the event of an accidental fall.

4. Apparatus as claimed in claim 3, in which the restraining means is in a permanently disposed, operative condition or is extendable or deployable (e.g.

by being telescopic or inflatable) or otherwise displaceable into its operative position.

5. Apparatus as claimed in claim 3, in which the restraining means comprises at least one inflatable means for providing supporting and/or restraining protection.

6. Apparatus as claimed in claim 5 further including a source of pressurised gas or means for receiving such and communicating with said inflatable means and an inertia switch or jerk sensing/responsive means or other operating means for permitting pressurised gas to flow from said gas source or receiving means to said inflatable means.

7. Apparatus as claimed in claim 5 or 6, in which the inflatable means is for restraining/supporting at least the neck region and comprises a neckbag which is a small collar shaped inflatable bag.

8. Apparatus as claimed in claim 6, in which the neckbag is incorporated into the upper assembly of fall protecting harness.

9. Apparatus as claimed in at least claim 5, in which, in its deflated condition, a collapsed and gathered neckbag is integrated into the shoulder region of the harness.

10. Apparatus as claimed in at least claim 6 in which the other operating means comprise tension sensing means in the anchor point for a suspension lanyard or in a suspension lanyard when combined therewith, or in the fall arresting system, or comprise an air pressure sensing means, a drop counter propeller or a photocell which is exposable by the action of the tension of the lanyard on a cover for the photocell; said sensing and/or operating means being operable to activate a valve on/for a miniature compressed gas bottle to inflate the inflatable means.

11. Apparatus as claimed in any of claims 4 to 10, in which the inflatable means is in the form of a neckbag and is such that when inflated it envelops the cheeks, neck and chin area of the wearer to restrain that part of the body.

12. Apparatus as claimed in any of claims 4 to 10, in which the inflatable means or neckbag is made as to envelop the whole of the back of the head like a hood to give even more protection.

13. Apparatus as claimed in any of claims 4 to 12, in which other inflatable bags are used in various pressure contact points on the harness.

14. Apparatus as claimed in any of claims 4 to 13, in which a connecting lanyard, such as a rope, chain, wire or cable, is provided connectable at one end to a support structure and at the other end to the harness.

15. Apparatus as claimed in any of claims 4 to 13, in which the harness includes energy absorbing means preferably provided as part of the harness attachment point.

16. Apparatus as claimed in claim 15 in which the energy absorbing means comprises a strip, flap or other partially separable portion non-releasably secured in one region to the harness and in another region having an attachment member to which a suspension lanyard is connectable whilst on an intermediate region said partially separable portion is adhered, bonded stitched or otherwise releasably attached by attachment means to the harness such that when a fall occurs, the stitches will be broken or other attachment means detached to release said portion and to provide a head restraining means and/or absorb energy thereby.

17. Apparatus as claimed in claim 16, in which the partially separable portion is arranged, shaped and dimensioned, e.g. as a triangular flap, to act to support the back of the head when partially ripped away from the harness.

18. Apparatus as claimed in any of claims 4 to 17, in which the harness includes an audible alarm means operable by the exhaust gas from the inflatable means on deflation.

19. Apparatus as claimed in any of claims 1 to 18, in which the inflatable restraining means comprises a safety device on its own or one securable to an existing harness as an adaption or be securable to a safety helmet or hat ("hard hat") or incorporated or be securable to a safety helmet such as that of a motor cyclist or aircrew helmet or be incorporated therewith or be connectable to or incorporated in a vehicle seat, together with the appropriate pressurised gas source or means for receiving such and an appropriate sensing and activation means.

20. Safety apparatus, for protecting the rear head and/or rear neck region of a person from the affects of injurious accelerations and jerks comprises at least one inflatable restraining means carried by or forming part of an article which is to be worn by the person to be protected or to be juxtaposed said person, a source of pressurised gas and/or means for receiving such and communicating or cortununicatable with said inflatable means, and an inertia switch or jerk sensing/responsive means for permitting pressurised gas to flow from said gas source or receiving means to said inflatable means, said inflatable means being located on said article such that in the normal position of use and juxtaposition and upon inflation, the inflatable restraining means inflates to provide support and/or restraining protection to the head and/or neck to prevent or inhibit undesired rearward movement of the head.

21. Apparatus as claimed in claim 20, in which the inflatable restraining means is located in or on a vehicle seat to counteract "whiplash".

22. Apparatus as claimed in claim 21, in which the inflatable means is located in the region of or in the head rest/restraint.

23. Safety apparatus substantially as herein described with reference to the accompanying drawings.