ROAD VEHICLE SPEED RESTRICTION DEVICE The subject invention concerns a device designed to restrict the speed of road vehicles passing over the device. In different traffic environments it is desired that the speed of vehicles driven through a particular stretch of the road, be kept very low. Examples of such environ¬ ments are residential areas, road sections with restricted visibility or road-work sections where part of the roadway is occupied on account of the work in progress and where furthermore the workmen must work on the road in close proximity to the passing vehicles.

Signs indicating the maximum speed allowable has, unfortunately, proved too unefficient a method to prevent all drivers from obeying the set speed limit. The re¬ stricted resources of the police do not either allow con¬ tinuous surveyance of the traffic in every road section where speed restrictions are required. In residential areas, for instance, permanent road humps are often installed in the road surface in conjunction with clear markings forewarning the driver of the position of such road barriers. These bumps force the driver to reduce the speed when passing the barrier, or else he runs the risk of damaging his vehicle. In the case of road work in progress, where it is desired to reduce the speed of passing vehicles, permanent installations in the form of humps in the roadway are not very suitable, for obvious reasons, since the road works generally are of comparatively short duration. Still, in this case it is particularly important that the traffic advances at a very slow pace past the road work in progress in view of the fact that the activities of the workmen take place very close to the passing vehicles and that often the nature of the work prevents the workmen from paying attention to the traffic.

The subject invention provides a device which is a functional and efficient supplement to signs warning drivers of a forthcoming heavy speed restriction, as well as to cautionary information tables. The supplement in accordance with the invention consists of a road vehicle speed restriction device the characteristic features of which are defined in the appended claims. The speed restriction device is dimensionally adapted to ensure that a driver passing the device at too high speeds is made aware of this fact by impacts on the vehicle and a heavy sound bang, and that consequently he must decelerate immediately.

The invention will be described in closer detail in the following with reference to the accompanying drawings, wherein

Fig. 1 is a perspective view of a section of a road¬ way on which is deposited a speed restriction device in accordance with the invention.

Fig. 2 is a cross-sectional view through the profile body incorporated into the speed restriction device,

Fig. 3 is a section on a larger scale along line III- III of Fig. 2, and

Fig. 4 is a broken plan view of a part of the speed restriction device. The road vehicle speed restriction device in accord¬ ance with the invention is constructed from a number of interconnected profile bodies 1. Each profile body 1 con¬ sists of a piece 2 of arch-shaped sheet metal which is mounted in two elongate feet 3 and 4, the latter prefer- ably presenting ribs 5 and 6, respectively, on their upper and lower faces and consisting of a material having a high coefficient of friction against the support, such as an asphalt-covered roadway 7. At either side, the profile body 1 has an end wall 8 and in accordance with the embodiment illustrated, the profile body may have a sheet metal base 9 extending between the feet 3, 4.

The profile bodies 1 are interconnected by means of chain links 10 which are screwed into the end walls 8 with the aid of threaded bolts 11 and nuts 12.

In the manner appearing from Fig. 1, a length of profile bodies 1 thus interlinked is deposited across a roadway 7, in the transverse direction thereof, at a point immediately ahead of e.g. a section of the roadway where work is in progress. It is assumed that the direction of traffic on the roadway 7 is from the left to the right as seen in Fig. 1. When a vehicle reaches the speed restric¬ tion device, its front wheels will first roll over the rear feet 4 of a couple of profile bodies 1, some of the weight of the vehicle pressing the profile bodies 1 against the roadway 7. When the wheels pass the crest of the arched sheet metal element 2, which forms a hump, the wheels will no longer abut against the sheet metal element 2 and will thud down a bit further ahead, so as to achieve contact with the front edge of the profile body 1 or with the roadway 7, depending of the speed of the vehicle. A thump and the sound of a heavy blow on the vehicle imme¬ diately make the driver aware that he must drive his vehicle at a reduced speed over this particular section of the road. The same course of event takes place at the very next moment, when the rear wheels of the vehicle pass over the speed restriction device.

Several rows of speed restriction devices in accord¬ ance with the invention, placed in parallel at intervals across the roadway, obviously fulfil even better their intended purpose of reducing the vehicle speed on the associated section of the road.

The road vehicle speed restriction device in accord¬ ance with the invention is a comparatively light construc¬ tion and when the road work is completed, it may easily be lifted by one or a couple of workers and be transported to the next road section, where new road repairs are to start. Owing to the construction, having a large surface in engagement with the roadway surface 7 and using chain

links 10 as the body interconnection means, the speed restriction device remains firmly in position in the longitudinal direction of the road while at the same time it adjusts itself to any surface unevenness in the transverse direction of the roadway.

The road speed restriction device is not, however, limited to the embodiment described and illustrated but may be varied in many ways within the scope of the appended claims. This applies to the configuration of the profile bodies 1 as well as to their feet 3, 4 and the links 10.