GB2571134A

GB2571134A - Protective headgear

Info

Publication number: GB2571134A
Application number: GB1802702.9A
Authority: GB
Inventors: John Pollard Darren
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-02-20
Filing date: 2018-02-20
Publication date: 2019-08-21
Anticipated expiration: 2038-02-20
Also published as: GB2571134B; GB201802702D0

Abstract

Protective headgear 4’ comprising an array of proximity sensors 24, the proximity sensors being located when the headgear is being worn so as to detect objects approaching the headgear from above the transverse plane of the wearer, and an alarm 28,30,32 to provide an alert to the wearer as an object comes within a threshold distance of the headgear and an indication to the wearer of the direction the object is approaching from. Preferably there is a proximity sensor at the crown of the headgear, and three more around the circumference of the helmet. The alarm may be at least one of an optical, sonic or haptic alarm. If the alarm is optical, it is preferably fitted to the underside of a peak 6’ of the headgear. There may be a transmitter to transmit signals from the proximity sensors, and there may be a receiver to receive signals from remote sensors.

Description

FIELD OF THE INVENTION

The present invention relates to protective headgear, particularly but not exclusively for use with hard hate (also known as safety- hate, construction hate or construction helmets).

BACKGROUND ART

Hard hate are rigid protective helmets in widespread use and worn by construction workers, tree surgeons, miners, some factory/ workers, firemen and the like to protect the head from Impact injury. Similar hats are worn for protection in sporting pursuits such as climbing, caving and potholing. There are many different designs of hard hat, but most share a number of common features as shown in Figures la and lb: in these drawings, the hard hat 2 has a rigid shell 4, usually made of plastic, which is generally dome-shaped and may have strengthening ridges or ribs (not shown in Figure 1) and/or ventilation holes (not shown) formed in it. The shell 4 has a horizontally-protruding peak 6 at the front circumferential edge which, when the hat is worn, sits over the wearer's forehead to protect the wearer's eyes from falling objects or from falling rain; usually there is a projecting edge 8 running around the remaining circumferential edge of the hat to divert rain away from the wearer's head. Often the shell 4 is formed with hollow protrusions 5 and/or siots (not shown) to accommodate various items or fixings, either outside the hat or more usually to provide space for such elements inside the hat 2. Tne interior of the shell 4 may be provided with a cushioned lining 10 (such as foamed plastic), and within this (if fitted) is a crown strap suspension 12 which is intended to fit closely to the wearer's head leaving a small gap between the head and the shell 4 or lining 10; the purpose of this gap is primarily to add to the protection - the impact of anything which hits the outside of the hat 2 is initially absorbed by the shell 4 and transferred via the suspension 12 around the head, so blunting a sharp trauma and meaning that in the event an impacting object deforms or pierces the 5 shell 4 the deformation or penetration has to be significant before it reaches the head. The gap also aids ventilation, to keep the wearer more comfortable in hot weather. The crown strap suspension is usually made of a flexible material, such as a plastic or fabric material, and generally consists of a headband 14 which fits around the circumference of the head at forehead level, and a number of straps 16 which extend over the crown of the head (there 10 are many different crown strap arrangements, such as there being an upper circumferential circle, ring or band of material which sits atop the head with straps extending vertically between the headband and this upper circle). There Is usually some means 19 of adjusting the circumference of the headband 14, and the length of the straps 16 (not shown), so as to provide a comfortable fit for the wearer, and the rear of the headband may dip down, or 15 have a separate piece, to form a nape strap 18 which engages with the back of the wearer's head to prevent the hat from moving forwards on the head so that the peak 6 tips over the wearer's nose. A sweatband 20 may be provided, either on the front part of the headband

14, over the wearer's forehead, or extending around the headband, and there may be a chinstrap (not shown), which may be adjustable, extending from either side of the 20 headband 14 down and under the wearer's chin. The lugs 5 mentioned above which are formed in the shell 4 create internal space which can accommodate parts of the crown strap suspension 12, such as the fixings 22 between the straps 16 and the headband 14, a means for adjusting the headband circumference (if this is provided on the headband 14 rather than on foe nape strap 18 as shown in Figure lb), or the means (not shown) for adjusting 25 the iengths of the straps 16.

In most jurisdictions it is obligatory to wear hard hats when using an aerial work platform such as a cherry picker machine (also known as a boom lift or a basket crane) or scissor lift. Such aerial work platforms are designed to lift an operator into the air vertically, and often so as to also move the operator in foe horizontal plane; many such platforms are 30 controlled by the operator located on the platform (i.e. in the basket) using a conventional joystick, or other controls. One problem with such devices is that they are often employed in situations, such as in warehouses, building sites and amongst trees, where there are aerial hazards such as roofs or overhanging structures, electricity transmission lines, other moving

-3aerial work platforms or branches. Such hazards present a serious crush dancer in that an operator may not notice that he is moving the platform closer to such a hazard and, although he may stop moving the joystick or release the controls when he becomes aware of the hazard, this might not be until point, at which the hazard physically touches him or the basket, and the latency in such platform's control systems (which are often hydraulic) means that the basket can keep moving towards the hazard for some moments, which can result in the operator being crushed between the basket and the hazard. If the hazard is a high voltage transmission line, simply coming into contact could seriously injure the operator. Moreover, where the hazard is moving outside of the control of the operator (e.g. a branch blown by the wind, or another aerial work platform) even If the operator stops movement of his work platform, the hazard may continue to move and crush the operator. There could be several hazards of different types in a particular situation. To try and address these problems it has been suggested that the basket be equipped with proximity sensors, such as in US 2015/0368082. but such systems usually operate by bringing movement of the platform to a halt when the basket moves to within a certain threshold distance from the hazard detected by the sensors. The basket in an aerial lift platform is usually quite large, big enough for the operator to move around in, which means that the threshold volume within which the system stops movement is significantly bigger than the basket; whilst this may be good from a safety perspective, it limits the capability' of the platform to approach a position where it may be close to a hazard, but the operator within the basket can still work perfectly safely because he Is at the other side or end of the basket, for example. There is a need for a system which reduces the safety threshold volume to that which is absolutely necessary to protect the operator or other workers in the basket.

Another problem with conventional crush danger protection systems for aerial work platforms arises because they usually just stop the platform from moving further, unless the operator activates an override control; if the operator cannot see any hazard, or if he mistakeniy believes there is sufficient clearance to carry on moving (perhaps because there are two hazards and he only notices one, which is distant, but not the second which is doser), the operator may activate the override control, continue the platforms movement and crush himself (or another worker in the basket) between the hazard and the basket

-4SUMMARY OF THE INVENTION

The present invention is predicated on the realisation that if the operator is entirely within the basket there can be no crush hazard; although the basket may impact against the hazard, the lower part of the operator's body will always be protected by the basket structure. The inventor has realised that in normal use, it is the operator's upper body which protrudes from the basket and, when the operator is controlling movement of the platform, it is usually the operator's head which projects furthest from the basket and which is therefore most exposed to impact against a hazard as a prelude to a crush incident.

The present invention therefore provides protective headgear comprising an array of proximity sensors, the sensors being located when the headgear is being worn so as to detect objects approaching the wearer's head from any direction generally above the transverse plane of the wearer, and an alarm to provide an alert to the wearer as an object comes within a threshold distance of the headgear and an indication to the wearer of the direction the object is approaching from.

With such an arrangement the operator is not only alerted when there is a risk the most exposed and vulnerable part of his person, his head, might impact on some hazard but also there is an indication of where the danger is coming from: the operator not only knows to stop movement, or to duck his head, but also which way to duck it

Proximity sensors are sensors which are able to detect the presence of nearby objects without any physical contact, and usually work by emitting an ultrasonic or electromagnetic field or beam of ultrasonic or electromagnetic radiation (infrared, for instance), and looks for changes in the field or in the signal reflected by the object. The maximum range at which a proximity sensor can detect is defined as the nominal range which may be adjustable for some proximity sensors, proximity sensors also have differing fields of view (or field of detection), which also may be variable. As will be explained, all variations and combinations of nominal ranges and sensor field of view? may be used in headgear in accordance with the invention.

The normal human visual field extends to approximately 107 degrees outwardly left and right from the sagittal plane and in the transverse/horizontal plane (so does not extend as far as the coronal plane) and up to about 70 degrees above and 80 degrees below the

-5' horizontal plane., in the sagittal plane (for convenience, Figure 2 illustrates these hypothetical cardinal planes relative to the human body). These are normal maxima, but there should be a safety margin to take account of possible visual field loss through injur/, age or obstruction; in addition, if a platform operator moves in any significantly vertically downward direction (he. below the transverse plane) the basket will protect the operator because the basket is most likely to impact on any hazard before the operator does - and, the operator is more likely to be looking in the direction of movement if that movement is downwards (or has a significant downward dimension). Accordingly the sensor array need not sense hazards approaching from all directions, but only those outside the typical visual field and largely above the horizontal plane. Thus the sensors in the array may be located and adapted so as to sense hazards approaching from above the horizontal plane (or at a positive elevation), and/or outside 100 degrees outwardly left and right from the front of the wearer of the headgear (Le. the sagittal plane), and/or outside the arc from 60 degrees above the horizontal immediately to the wearer's front to horizontal at the points on the horizontal plane at 100 degrees to the left and right. Because the nape, or lower rear part of the head is particularly vulnerable, it may be desirable to have a sensor to provide detection below the transverse plane localised in the region immediately behind the wearer (so the term generally used above and in the claims should be construed to encompass an arrangement in which the combined field of view of the array of sensors is above the transverse plane apart from in the vicinity of the nape of the head where the field of view may extend downwardly by as much as 10 to 30 degrees).

Given that the principal direction of movement of the aerial work platform is vertically upward, there may be a proximity sensor provided on the top of the headgear, at the crown. Alternatively, the approach of hazards from vertically above the wearer could be sensed by a number of sensors located away from the crown of the headgear but arranged around the headgear but distanced from it. The most appropriate locations for the individual sensors of the sensor array depend on the range, field of view and sensitivity of the sensors themselves; also, toe number of sensors ano their cost will affect toe precise number and location of the individual sensors, and this is something which may vary according to the situation where the headgear Is to be used. We would envisage that there would need to be at least three proximity sensors in the array to cover the desired range of movement of likely hazards, with a nominal range of about Im, about 0.5m or about 0.25m, but there could be four, five, six or any number arranged around the circumference of toe headgear at

-6at least one level below the crown. For applications where there are likely to be many close hazards (such as in caving or tree surgery for example) it may be desirable to have a large number of proximity sensors, each having a relatively small nominal range, of about 10cm to about 30cm. In other applications there could be a mix of sensors with different nominal ranges, so as to reflect the fart that when the headgear is in use hazards are more likely to approach from particular directions, or at different speeds (so the faster the approach, the greater the nominal range in that direction), and sensors with a smaller field of view may be used so as to fill in any gaps in the overall field of detection. There could be a subset of sensors with a relatively large nominal range arranged to detect hazards at a greater distance in some directions, with another subset of sensors of lesser nominal range to detect hazards approaching from other, less dangerous directions. The proximity sensors may have different fields of detection, so a single sensor with a wide angle of detection but a relatively short nominal range could be used in a location where it is thought unlikely that a hazard could approach from, or could approach from without being noticed, such as from directions only just outside the human field of view, whereas directions which are deemed high risk could have sensor(s) with relatively large nominal ranges and narrow fields of view. Such different proximity sensors could be combined so as to provide an overlapping field of detection (or a least one with very few or small gaps) covering the entire volume around the headgear. It may be advantageous for the nominal range(s) of the proximity sensors to be adjustable, to accommodate different situations (to allow fast movement when there are no objects in close vicinity, but to adjust to slower movement when there are many objects in the vicinity) or different usages (e.g. changing the use from a construction environment to an arboreal one).

The alarm may be an optical alert system, and/or a sonic alert system, and/or a haptic alert system. An optical alert system could comprise an array of steady and/or flashing lights or LEDS located in the wearer's field of view, with the arrangement of the lights and/or their colours being used to indicate the range of a hazard from the headgear, the direction from which the hazard is approaching, and/or the speed at which the hazard is approaching (for example, the lights could be arranged in a pattern to indicate the direction of approach, they could change from green through amber to red as a hazard gets closer, and/or they could flash if the hazard is approaching quickly). A sonic alert system could comprise a loudspeaker or headphone(s) which emits sounds of various kinds and/or tones according to a hazard's range, speed or direction, additionally or alternatively it could issue

-/spoken warnings, such as LEFT REAR, RIGHT SIDE UP to indicate direction, with additional words and/or an increase in volume to indicate reducing range and/or speed of approach. A haptic alert could comprise smali vibrators inside the headgear configured to vibrate against a wearer's head, and would be most useful in indicating to the wearer the direction of approach of a hazard, although range and/or speed of approach could also be communicated by the amplitude or frequency of vibrations, Having alert systems which engage with different human senses is advantageous in situations where there are sensory distractions; in a noisy environment, for example, an optical alert can still be seen and a haptic vibration felt. The alert could consist of any one of an optical, sonic or haptic alert, or any combination of these.

The headgear could be any hat, but preferably is one with a forwardly-projecting peak, such as a hard hat, helmet or cap, including soft caps such as baseball caps, in which case the optical alert array could most conveniently be located to the underside of the peak where it is within the wearer's field of view but does not obscure it, and it is protected from the elements. If there is a nape strap, one or more proximity sensors could be mounted to the nape strap to detect hazards approaching the hat from behind the wearer, within a reasonable transverse angle such as about 3Q to 45 degrees to right and left, and below the transverse plane.

In applications where the headgear comprises a flexible headband and at least two flexible crown straps extending from the headband over the head, such as in most hard hats, the proximity sensors could be mounted to the exterior of the headband and/or the crown straps, with any haptic vibrators being mounted to the interior of the headband and/or the crown straps. The headgear comprising a flexible headband and crown straps could be made of some elasticated fabric or synthetic material, so that the proximity sensors and alarm system could be fitted to an existing hard hat or other type of hat as a retrofit, without damaging the hat, or the headgear could be worn directly on the head without any other covering.

A transmitter could be provided so as to transmit signals indicative of an approaching hazard from the array of proximity sensors. This would be useful when the headgear is in use with an aerial work platform, in that the signals indicating an approaching hazard could be transmitted to a controller in or on the platform, which could halt or slow down the

-8movement of the platform without requiring any input by the platform operator, which would be advantageous when there is more then one person In the platform basket with only one controlling movement of the platform, or if the person controlling movement of the platform is not inside the basket but is remote from it, such as on the ground. There could 5 be a receiver to receive signals from remote sensors other than the array of proximity sensors forming part; of the protective headgear, the signals corresponding to the detection by the remote sensors of approaching objects, the alarm being adapted to provide an alert to the wearer corresponding to the signals from the remote sensors. In this arrangement the person controlling movement of the platform could be alerted by proximity sensors 10 mounted on the platform and/or by proximity sensors in headgear worn by another person in the basket, so as to stop the platform from moving in such a way as.to cause an impact between the hazard and the basket and/or the head of the other person(s).

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example and with reference to the accompanying figures, in which;

Figures la and lb are schematic views of a typical hard hat, in partial cross-section from the side, and from below;

Figure 2 is an illustration of the hypothetical cardinal planes used to transect the 20 human body in order to describe the location of objects or structures, or the direction of movements relative to the human body:

Figure 3a is a perspective schematic view of a hard hat incorporating protective headgear in accordance with the invention;

Figure 4 is a plan view of the hard hat of Figure 3;

Figure 5 is a perspective view from below of Figure 3 showing the interior of the hard hat;

Figure 6 is a schematic view of an optical alert system forming part of the apparatus of the present Invention, and ~9Figure 7 is a schematic view of another embodiment of protective headgear in accordance with the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the Figures, elements which are the same or perform the same function as that of a conventional hard hat as shown in Figure I are denoted by the same reference numeral, but with a dash.

Figure 3 shows a hard hat 2' formed with a generally dome-shaped shell 4' made of a tough and rigid plastic material and which has a peak 6' which projects forwardly over the 10 nose when the hat 2/ is being worn, and a circumferential rim 8', Disposed on the outer surface of the shell are proximity sensors 24 - in the example four are shown, but as explained above the number and location of the proximity sensors is a matter of design according to the intended use of the hard hat 2'. Figure. 4 is a plan view of the hard hat of Figure 3, showing also the protrusions 5' moulded into the shell 4' for receiving fittings 15 inside the hat; there is also a large protrusion 26 at the rear of the hat 2' which is usually provided for receiving part of the fitting adjustment mechanism (not shown) inside the shell 4', but It may be sufficiently large to receive additionally a battery and control system pack as will be described.

Figure 5 is a view of the hard hat of Figures 3 and 4 from below, showing the interior 20 where a user's head fits. Underneath the peak 6' or brim of the hat there is an optical display 28 (described further below) for alerting the wearer of a hazard approaching the hat; the display 28 may be fixed adhesively permanently or semi-permanently to the peak 6, or it may be releasably attached, by way of hook, and loop tape fastener for example. The display 28 is fitted in a location where it is out of the direct line of sight of a wearer, but still within 25 his overall field of view, so that he has only to raise his eyes slightly to see the display..

Similarly fixed to the interior of the shell 4' in the vicinity of the wearer's ear is a loudspeaker (or a pair, one near to each ear) for providing an audible warning to the wearer of a hazard approaching the hat, Mounted to the crown straps 16' are haptic sensors 32, which vibrate next to the wearer's skull and thus give the wearer a haptic alert, of a hazard 3G approaching the hat. Finally, a battery and control system pack 34 is mounted in the space

-10between the shell 4' and the crown strap suspension; it may be mounted as for the display 28 or loudspeaker 30, to the interior surface of the shell, and/or there may be sufficient space inside protrusion 26 for it to fit within that protrusion 2.6. The active elements of the system (sensors 24, display 28, loudspeaker 30, vibrators 32 and battery and control system 5 pack 34 are connected by suitable electrical wiring (not shown in the drawings for clarity, but running along the headband and the crown straps), powered by batteries in the pack 34, and operate generally as described above,

Figure 6 shows the optical alert display 28 of Figure 5 in greater detail. It comprises a generally flat body (which may be slightly flexible so as to conform to the general shape of 10 the peak to which it is to be fixed) having three lines 36, 38, 40 of LEDs 42 which converge on a larger light or LED 44. LED 44 represents the wearer's head and LEDs along lines 36, 38, 40 light up progressively as a hazard approaches the headgear. These LEDs may be of different or variable colours, so that as a hazard gets cioser the colour of the closest LED changes from green to amber and then red, Additionally or alternatively the LEDs may flash IS at a speed corresponding to the speed of approach of the hazard. The large LED 44 may light up when an impact is Imminent, or it could be a colour variable LED and used to indicate the approach of a hazard from vertically above, changing from green to red as the hazard draws nearer.

A microprocessor or other controller inside the battery and control system pack 34 is 20 programmed to give an audible alert, via the loudspeakers. It may be programmed to respond to one proximity sensor alone, and give only a genera! indication as to the direction and speed of approach of a hazard, or it may be capable of assessing the signals generated by several proximity sensors so as to determine more accurately the direction and speed of approach, and give a more detailed audible alert to the wearer. The controller could be 25 programmed to increase the volume of the audible alert in response to an increase in the perceived risk of impact between the hazard and the operator.

Figure 7 shows from underneath another type of headgear, which is similar to the suspension system of a hard hat: there is a headband 72 formed of a flexible fabric or synthetic material, which is preferably elasticated, and joined to it are three crown straps 30 74, formed of a similar flexible and/or elasticated material. This forms an open structure which would extend over but not cover completely a wearer's head, and is hereinafter

-11referred to as a '’cap''. Such caps might not give as much physical protection to a wearer's head than a structure which completely covers the head, but they may be mare comfortable and cooler in certain conditions. The caps could be worn directly on the head, which couid be advantageous in a confined space, such as when climbing or potholing, or they could be fitted over a conventional hard hat or other form of hat (enabling an existing hard hat to be retro-fitted, and/or obviating the need to adhere or mount anything to the shell of the hat, which could compromise its structural integrity and/or be contrary to regulations covering such hard hats). Proximity sensors (not shown) are located on the outside of the crown straps, as indicated generally by arrow 76 and as described in connection with Figure 3, and haptic vibrators 78 are fixed to the inside of the crown straps 74. Loudspeakers 80 are mounted to either side of the headband 72, a battery and control system pack 82 is mounted to the rear of the headband 72, and a smail frontal peak 84 is provided for mounting an optical display as described above. The cap shown operates in the same manner as has been described in connection with hard hats, with electrical power and control wiring running along or inside the headband 72 and the crown straps 74.

It will of course be understood that many variations may be made to the abovedescribed embodiment without departing from the scope of the present invention. For example, the haptic vibrators inside the hat or cap may correspond in position with the proximity sensors on the outside; alternatively there may be a smaller number of vibrators ’which are positioned so as to give a general haptic indication of the direction from which a hazard is approaching, For example, there may be one vibrator at the crown and three more arranged further down, at 100, 180 and 280 degrees from the forward direction which vibrate singly or in pairs, so as to indicate the general direction of approach (i.e, Left, Rear, Right, Upper Left, Upper Rear, Upper Right and Directly above). Although described specifically with reference to a hard hat, it will be appreciated that this type of headgear couid be incorporated in any type or headwear, even headwear which does not have a peak - as a separate peak could be provided which is attachable to the front of the headwear. As mentioned, the caps could be worn directly over the head, or they could fit over another piece of headwear. If the hat has no peak, it may be that an optical alert is not used but instead only a sonic and/or a haptic one.

Where different variations or alternative arrangements are described above, it should be understood that embodiments of the invention may incorporate such variations and/or alternatives In any suitable combination.

-13CLAIMS

1. Protective headgear comprising an array of proximity sensors, the proximity sensors being located when the headgear is being worn so as to detect objects approaching the headgear from any direction generally above the transverse plane of the wearer, and an aiarm to provide an alert to the wearer as an object comes within a threshold distance of the headgear and an indication to the wearer of the direction the object is approaching from.

2. Protective headgear according to Claim 1., in which the headgear has a crown, or topmost point, and the array of proximity sensors includes a proximity/ sensor at the crown.

3. - Protective headgear according to Claim 1 or 2, in which the headgear has a crown, or topmost point, and the array of proximity sensors includes at least three proximity sensors arranged around the circumference of the headgear at a level below the crown.

4, Protective headgear according to any preceding claim, in which the proximity sensors have different nominal ranges.

5. Protective headgear according to any preceding claim, in which the proximity sensors have different fields of detection,

6. Protective headgear according to any preceding claim, in which the alarm is at least one of an optical,, sonic or haptic alarm.

7. Protective headgear according to Claim 6, in which the or each alarm is adapted to provide an alert as to the distance of the approaching object from the headgear.

8. Protective headgear according to any preceding claim, in which the protective headgear is releasably fitted to or integral with a hat.

9. Protective headgear according to Claim 8, in which the hat has a forwardly-projecting peak and there is an optical alarm, the optical alarm being fitted to the underside of the peak.

-1410> Protective headgear according to Claim S or 9, in which the hat is a hard hat or a cap.

11. Protective headgear according to Claim 8, 9 or 10, in which the headgear comprises a nape strap, and a proximity sensor is mounted to the nape strap to detect hazards approaching the hat from behind the wearer and below the transverse plane.

12. Protective headgear according to any of Claims 1 to 6, in which the headgear comprises a fiexibie headband and at least two flexible crown straps extending from the headband over the head, the proximity sensors being mounted to the headband and/or the crown straps.

13. Protective headgear according to Claim 11, in which the headband and/or the crown straps are formed of elasticated fabric material.

14, Protective headgear according to any preceding claim, in which there is a transmitter to transmit signal's from the array of proximity sensors.

15. Protective headgear according to any preceding ciairn, in which there is a receiver to receive signals from remote sensors other than the array of proximity' sensors corresponding to the detection by the remote sensors of approaching objects, the alarm being adapted to provide an aiert to the wearer corresponding to the signals from the remote sensors.

Claims

1. Protective headgear comprising an array of proximity sensors, the proximity sensors being located when the headgear is being worn so as to detect objects approaching the headgear from any direction generally above the transverse plane of the wearer,

5 and an alarm in the form of an optical and/or sonic alarm to provide an alert to the wearer as an object comes within a threshold distance of the headgear and an indication to the wearer of the direction the object is approaching from.

2. Protective headgear according to Claim 1, in which the headgear has a crown, or topmost point, and the array of proximity sensors includes a proximity sensor at the

10 crown.

3. Protective headgear according to Claim 1 or 2, in which the headgear has a crown, or topmost point, and the array of proximity sensors includes at least three proximity sensors arranged around the circumference of the headgear at a level below the crown.

15

4. Protective headgear according to any preceding claim, in which the proximity sensors have different nominal ranges.

5. Protective headgear according to any preceding claim, in which the proximity sensors have different fields of detection.

6. Protective headgear according to any preceding claim, in which the the proximity

20 sensors are located and adapted so as to sense hazards approaching from directions outside 100 degrees outwardly left and right from the the front of the wearer of the headgear, and/or outside the arc from 60 degrees above the horizontal immediately to the wearer's front to horizontal at the points on the horizontal plane at 100 degrees to the left and right to the wearer's front.

25

7. Protective headgear according to any preceding claim, in which the or each alarm is adapted to provide an alert as to the distance of the approaching object from the headgear.

18 10 18

10. Protective headgear according to Claim 8 or 9, in which the hat is a hard hat or a

5 cap.

12. Protective headgear according to any of Claims 1 to 6, in which the headgear

10 comprises a flexible headband and at least two flexible crown straps extending from the headband over the head, the proximity sensors being mounted to the headband and/or the crown straps.

15 14. Protective headgear according to any preceding claim, in which there is a transmitter to transmit signals from the array of proximity sensors.

15. Protective headgear according to any preceding claim, in which there is a receiver to receive signals from remote sensors other than the array of proximity sensors corresponding to the detection by the remote sensors of approaching objects, the 20 alarm being adapted to provide an alert to the wearer corresponding to the signals from the remote sensors.