Road hazard warning device
United States Patent Harris et al.  
  [451 Apr. 29, 1975 [54] ROAD HAZARD WARNING DEVICE 3.720.181 3/l973 Elkins lib/63 P Inventors: g a g l&#39; Charles Harris h FOREIGN PATENTS OR APPLICATIONS ort re d; Barry Ward, Redditc 965 3 G H6 63 Alan Ernest Barker, Dorridgc, all of I I England Primary E.\&#39;dl7llflf-LOUIS K. Rlmrodt [73] Assigneez Hazard Warning Systems Limited, Am w A em, or Firm-Spencer &amp; Kaye Birmingham, England [22] Filed: Feb. 5, 1974 57 ABSTRACT PP N03 439954 A device for warning drivers of vehicles of road hazards comprises a number of bodies connected by 52 vs. C] 404/15 1 16/61 R- 404/10 flexible Chain Each has [5i] Int Cl I I I I I I h b 9/04 a stepped upper side, a cavity at its underside and is [58] Field of Search i 16 9 shallow, as compared with its width and length. When placed on a road surface in the path of vehicles, the device can be seen by drivers under conditions of [56] References Cied good visibility and alerts a driver under conditions of poor visibility by providing an audible and mechanical UNITED STATES PATENTS warning when driven over. 3.485.l48 Il/l969 Heenan 404/12 3.717.326 2/1973 Leach ct al, 404/6 9 Claims, 7 Drawing Figures PAYENTEUAPR29|QY5 sum 3 0F 3 Q F1 .4. W 119 112 121 G 113 m 117 ROAD HAZARD WARNING DEVICE BACKGROUND TO THE INVENTION Known devices for warning drivers of temporary ha zards on roads provide a visual warning only and their effectiveness is therefore reduced under conditions of poor visibility. It is an object of the present invention to provide a road hazard warning device which can be seen and therefore provides a visual warning, and which also provides an audible and/or mechanical warning so that the device will be effective even under conditions of poor visibility.  
 SUMMARY OF THE INVENTION According to the invention we provide a road hazard warning means comprising a plurality of bodies which are placed in a row across a roadway, and for this purpose may be interconnected by flexible links, each body defining a cavity which is open at the underside of the body and the maximum depth of the body being less than one-half the average distance across the underside.  
  By the average distance across the underside we mean the average of the distances measured through a reference point at the centre of the underside between each point on the periphery of the underside and an opposite point on the periphery.  
 BRIEF DESCRIPTION OF THE DRAWING FIG. la shows a plan view of two devices in accor dance with the invention in position on one lane of a roadway,  
  FIG. lb shows on an enlarged scale a plan view of one body of the devices shown in FIG. la,  
  FIG. 2 shows the body of FIG. 1 in diametral cross section,  
  FIG. 3 shows an underneath plan view of an alternative form of body which may be incorporated in the de vices of FIG. la,  
  FIG. 4 is a sectional view on the line IV IV of FIG.  
  FIG. 5 is a sectional view of a further form of body which may be incorporated in the device of FIG. la, and  
  FIG. 6 shows in diametral cross-section a further form of body which may be incorporated in the device of FIG. la.  
 DETAILED DESCRIPTION FIG. la shows a two-lane roadway I, on the surface of which two devices in accordance with the invention, 2 and 3 respectively, have been placed to provide drivers of vehicles on one of the lanes with a warning of a temporary hazard. Each of the devices 2 and 3 comprises a plurality of bodies 10 arranged in a row extending transversely of the path of traffic. The bodies are placed in the path of traffic and the bodies of the device 2 are staggered with respect to the bodies of the device 3 so that the wheels of any vehicle which is travelling quickly in the lane concerned will encounter certain of the bodies 10.  
  The spacing between adjacent bodies 10 of the device 2 and of the device 3 is determined by flexible links 4 which connect the bodies of each device sequentially.  
  One of the bodies 10 is illustrated in greater detail in FIGS. lb and 2. This body is of circular shape when viewed in plan and is formed as a one-piece moulding. The body comprises an upper wall portion 11, a peripheral wall portion 12 which projects downwardly from the periphery of the upper wall portion and strut means in the form of a rib 13 which projects downwardly from the upper wall portion 11 internally of the body. It will be noted that the body defines a cavity which is open at the underside of the body. The height of the peripheral wall portion 12 is such that when the body is unstressed and is placed on a flat surface, both the upper wall portion 11 and the strut means 13 are spaced from such surface.  
  The upper wall portion 11 is stepped and includes lat erally outwardly facing riser faces. The peripheral wall portion 12 presents a further laterally outwardly-facing riser face. At at least one of these riser faces, the uppermost riser face in the example shown in FIG. 2, the body incorporates reflective elements I4. Such reflective elements may be formed of glass or plastics material and moulded into the body 10. Alternatively, the body 10 may be formed at one or more of the riser faces with a groove in which there is fitted a strip of plastics material bearing reflective elements or having a reflective surface. Such strip may be secured in the groove by means of an adhesive. Also, the groove may have a dove tail shape such that the strip is a snap-fit in the groove.  
  The rib 13 is of annular form and has a diameter approximately equal to one-half the diameter of the body III. The upper wall portion 11 and the peripheral wall portion 12 are thin. relative to the depth of the body between the upper side 15 thereof and the lower side 16 which is defined by the lower edge of the peripheral wall portion. The body is formed of a resiliently-flexible material, for example PVC, and when the upper wall portion I I is subjected to downward loading by a wheel of a vehicle, the body tends to collapse. Complete collapse of the upper wall portion onto the surface on which the body is standing is prevented by the rib I3 and thus when the downward loading is removed the body reverts to its original shape.  
  When the body 10 is particularly collapsed by downward loading of the upper wall portion 11, air is expelled from the interior of the body beneath the lower edge of the peripheral wall portion 12. Thus, when the body reverts to its original shape the pressure of air within the body falls below that of the atmosphere. Flow of air into the body between the surface on which it is standing and the peripheral wall portion 12 is sufficiently slow for a significant pressure differential to be maintained for a brief period as a vehicle wheel is rolling off the body. During this period the atmospheric pressure acting on the exterior of the body 10 presses the body onto the supporting surface sufficiently to prevent the body being displaced horizontally by the vehicle wheel. Thus although the body is not secured to the road surface or other surface on which it stands, it is not readily displaced from the required position by passage of traffic.  
  It will be noted that the lower edge of the peripheral wall portion 12 is tapered to provide an improved seal with a surface on which the body 10 is stood. If required, a strip of more flexible material may be incorporated in or attached to the peripheral wall portion adjacent the lower edge thereof to further improve the seal between the body and a surface on which it is stood.  
  The overall height of each of the bodies 10 is preferably within the range 2 to 5 inches, and the diameter of each body is preferably within the range 12 to 36 inches. Typical dimensions of the bodies 10 are an overall diameter of l8 inches, an overall height of 2%: inches, a general wall thickness of A inch and a peripheral wall height of 1 inch. In the unstressed condition, the lower edge of the annular rib 13 may be spaced three-eighth inch above the plane of the lower edge of the peripheral wall portion 12.  
  From FIG. 2 it can be seen that when the diameter of the underside is 18 inches the diameter of the horizontal face which defines the upper side 15 is 8 inches.  
  The peripheral wall portion 12 is formed at diametrically-opposite positions with horizontal apertures 17 for receiving end portions of the links 4. As shown, a peripheral wall portion includes internal enlargements around the apertures l7 to strengthen the peripheral wall portion at positions where it may be subjected to substantial stress.  
  The links 4 may each be in the form of a short length of rubber or other flexible material having enlargements at each end to retain end portions of the lengths within the apertures 17. The end portions of each link may include feet which are situated within the cavity defined by the body [0 and adjacent to the underside of the body for contact with a road surface on which the body is placed. Such feet would be formed of rubber or a like material having a relatively high coefficient of friction with respect to materials of which road surfaces are formed, so that the feet reduce the risk of the bodies 10 sliding across such surface.  
  The length of the links 4 is typically such that adjacent bodies ltl are spaced ]2 inches apart when the links are extended. The links 4 act as spacers so that the bodies 10 of the device 2 or of the device 3 can readily be spaced apart by the required distance without handling ofeach body being necessary. The links 4 also assist with the prevention of movement ofa body 10 from a position to which it has been set. Thus, should a vehicle wheel which rolls over a particular body 10 impart to that body a force tending to cause the body to slide along the road surface or to lift the body off the road surface, adjacent bodies will act on that particular body through the intermediary of the links 4 to retain such body in position. Although the bodies 10 are each free standing on the road surface, i.e., they are not secured to the road surface in any way, the positions of the bodies are not disturbed by traffic.  
  Referring now to the body shown in FIGS. 3 and 4, this body is also formed as a one-piece moulding from a plastics material. The body is of circular shape as viewed in plan and comprises an upper wall portion H] from the periphery of which there projects downwardly a peripheral wall portion 112. The upper wall portion includes a single step 118 which, as shown in FIG. 4, may be vertical, and two horizontal fiat portions extending respectively inwardly from and outwardly from the step. The step 118 and the peripheral wall portion 112 each present laterally outwardly facing riser faces, the heights of which are approximately equal and which may incorporate reflective elements, or be coated with reflective material. The step 118 is situated somewhat nearer to the peripheral wall portion than to the centre of the body so that the upper wall portion presents at the upper side of the body a central horizontal face and the distance across this face is greater than half the distance across the underside of the body.  
  The body further comprises strut means disposed internally of the body and having the form of two mutually orthogonal webs 113, each of which extends along a diameter of the body from the peripheral wall portion 112 at one side thereof to the peripheral wall portion at the other side. The webs 113 also extend downwardly from the upper wall portion H! to the same level as the lower edge of the peripheral wall portion so that when the body is stood on a flat surface, the webs 113 and the peripheral wall portion 112 both make continuous contact with the supporting surface.  
  The body 110 may be formed of a resiliently flexible material so that partial collapse of the body will occur when the upper wall portion 111 is subjected to downward loading by the wheel of a vehicle. Such partial collapse will cause air to be expelled from the cavity defined by the body, this cavity being open at the underside of the body. As the vehicle wheels roll off the body, the body will recover its initial shape and pressure within the body will be temporarily reduced. The atmospheric pressure acting on the outside of the body will force same against the supporting surface and prevent it being deslodged by the vehicle wheel.  
  Alternatively, the body 110 may be formed of relatively stiff material and be sufficiently rigid substantially to resist collapse when subjected to downward loading by the wheel of a vehicle. In this case, the moulding of which the body is formed may be reinforced internally, for example by elements of glass fibre reinforced resin bonded to the plastics moulding.  
  The peripheral wall portion 112 of the body 110 is formed with openings 117 to receive link elements corresponding to the links 4 shown in FIG. la. The link elements are lengths 119 of rubber or other flexible material, each having a head [20 at one end and a foot l2l at the other end. The head and the foot lie inside the peripheral wall 112 and the link elements extends therefrom through the openings 117.  
  The head 120 serves to prevent withdrawal of the adjacent end portion of the link element 119 from within the associated opening 117, and to close this opening. The foot 121 also serves to prevent withdrawal of the adjacent end portion of the link element from the associated opening 117.  
  The foot has the additional function of constraining the body against movement across a road surface on which the body rests. To this end, the foot projects a short distance, typically 5/32 of an inch, below the lower edge of the peripheral wall portion 112. The foot is also formed of a rubber composition which is softer than the material of which the body 110 is formed.  
  The diameter of the body 110 is between I and 2 feet, typically 1% feet, and the length of the link elements 119 is such that, when the links are extended, adjacent bodies are spaced approximately 1 foot apart. The overall depth of the body is typically 2 inches and is preferably within the range 1% to 5 inches.  
  The warning device illustrated in FIG. 5 of the accompanying drawings comprises a number of circular bodies, one of which is shown at 210. The body 210 defines a cavity 218 open atathe underside of the body. The body consists of an upper part 21 l and a lower part 212 which are premanently secured together, for example by means of an adhesive.  
  The lower body part 212 is in the form of an annulus or rubber or like material which has a high coefficient of friction with respect to road surfaces and which will therefore grip such road surfaces well. Typically the lower body part is one-halfinch thick and has a diameter within the range to 25 inches.  
  The upper body part 211 has a diameter somewhat less than that of the lower body part 212 so that a laterally facing shoulder 219 is presented at the periphery of the upper body part. The upper body part is of stepped form and presents at least one further laterally presented shoulder 220 which is above and spaced ra dially inwardly of the shoulder 219. The stepped form of the upper body part may be achieved by superposing two or more layers having different diameters, but it is preferred that the upper body part be formed as a onepiece moulding of a plastics material, for example PVC. The underface of the upper body part may be flat, but preferably this undersurface is recessed so that the cavity 218 extends into the upper body part, as shown. However, it will be noted that the cavity is closed at its upper end by the upper body part. Typically the thickness of the upper body part is l/2 inches.  
  The body 210 is connected with adjacent similar bodies indicated at 210a and 2101; respectively by a flexible link in the form of a cord or wire 221. Opposite ends of the link 221 are attached to the lower body parts of adjacent devices, the two links attached to the body 210 being disposed at diametrically opposite positions thereon.  
  A modification of the body 210 shown in FIG. 5 is illustrated in H6. 6. This body 310 consists of a plurality, for example four as shown in H0. 6, of superposed layers 322, 323, 324, 325 respectively. Each of these layers may consist of rubber, which term as used herein includes mixtures of rubber with fillers, pigments and like additives.  
  The layer 322 of the body 310 which is disposed at the underside thereof is in the form of an annulus having an outer diameter of 24 inches and an internal diameter of approximately in inches. The layer 323 is also of annular form with an outer diameter of inches and an inner diameter of 10 inches. The layer 324 is of annular form with an outer diameter of l4 inches and an inner diameter ofS inches. The layer 325 is an imperforate disc of diameter l l inches. The layers are arranged in superposed concentric relation so that each layer overlaps a part of the layer beneath it. The body thus defines a cavity which is open at the underside of the body. Furthermore. the upper side of the body is of stepped form and includes a plurality of vertical riser faces. Conveniently, each of the three lower layers is one-half inch thick and the uppermost layer 325 is 1 inch thick.  
  The layers 322 5 are adhered to each other. However, the layers could be secured to one another by some other means, for example adjacent layers could be riveted together. The number of layers may be varied if required. Also the shape of the body 310 and of each of the layers forming same may be other than circular. For example, each layer may be of rectangular shape when viewed in plan, both the shorter and longer edges of each layer excepting the lowermost one being shorter than the corresponding edges of the adjacent lower layer.  
  It will be noted that each of the bodies illustrated in the accompanying drawings is of relatively shallow form, the depth being less than one half the average distance across the underside.  
  it will be appreciated that the bodies may be used without interconnecting links such as the links 4 shown in FIG. la. In this case, the bodies would be placed individually to form one or more rows extending across a lane of a roadway.  
  Since a driver normally ovserves carefully the road surface ahead of his vehicle, under normal conditions of visibility, the bodies placed on the road surface will be seen by an approaching driver who will thereby be alerted to the possibility of a hazard being present on the road ahead. In conditions of poor visibility, or when a driver is not paying proper attention to the road ahead, he may fail to observe the bodies. When the wheels of the vehicle roll over respective bodies of the warning device, the vehicle will be subjected to an unexpected motion which will alert the driver. His automatic reaction would be to slow down. The device also provides the driver with an audible warning, since im pact between the bodies and wheels of the vehicle will produce a sound which, under most circumstances, would be heard by the driver.  
  To improve the visibility of the bodies, each of these may be formed of a brightly coloured material. Alter natively, the bodies may be painted or otherwise coated with a layer of coloured material.  
  ln the case of a warning device which comprises a plurality of bodies connected by flexible links, a body at one end of the chain of bodies may be attached to one end of a cord, wire or like flexible elongate member having a length which is a plurality of times greater than the length of the links extending between adjacent bodies. The chain of bodies can thus be drawn across a roadway by means of the elongate member by a person standing beside the roadway.  
 We claim:  
  1. A road hazard warning device comprising a plurality of bodies each having an underside and an upper side, and a plurality of flexible links wherein each body defines a cavity open at the underside of the body, the maximum depth of each body, as measured from the underside to the upper side, is less than one-half the average distance across the underside, said links connect said bodies sequentially and each link connects together a pair of bodies and is of predetermined length, when extended, whereby the spacing of adjacent bodies when the links are extended is predetermined by the links.  
  2. A device according to claim I wherein each of said bodies is formed of a resiliently-deformable material and further comprises strut means situated within said cavity for engagement with a surface on which the body is placed to prevent complete collapse of the body when the latter is subjected at its upper side to downward loading.  
  3. A device according to claim 1 wherein each of said bodies is resiliently deformable and further comprises strut means situated within said cavity for engagement with a surface on which the body is placed to prevent complete collapse of the body when the latter is subjected at its upper side to downward loading, and wherein, when the body is not stressed, the strut means is spaced from the underside of the body.  
  4. A device according to claim 1 wherein each body is provided with a plurality of feet which are disposed adjacent to the underside of the body for contact with a road surface when the body is standing thereon, and the feet are formed of a material having a relatively high coefficient of friction for impeding movement of the body across a road surface when standing on such surface.  
  5. Road hazard warning means comprising a plurality of free-standing bodies on a roadway surface. the bodies being arranged in a row across at least one lane of the roadway, each body defining a cavity open at the underside of the body and the maximum height of each body from the roadway surface being less than one-half the average distance across the underside of the body.  
  6. Road hazard warning means according to claim wherein the bodies are interconnected by flexible links and the respective links which extend between each pair of adjacent bodies are each of a predetermined length, whereby, when the links are extended, the position of one of said bodies is determined by the respective positions of two adjacent bodies.  
  7. A road hazard warning device comprising a plurality of bodies, each having an underside and an upper side and said bodies being interconnected sequentially by flexible links, wherein the maximum depth of each body, as measured from the underside to the upper side, is less than one-half the distance across the under side of the body, the upper side of each body is defined by a face which is horizontal when the body stands on a horizontal surface and the distance across said horizontal face is at least four-ninths the distance across the underside of the body.  
  8. A device according to claim 7 wherein said distance across said horizontal face is greater than onehalf the distance across the underside of the body.  
  9. A device according to claim 7 wherein the distance across the underside of each body is within the range l to 3 feet.