A RETRACTABLE ROAD BARRIER

Abstract: A retractable road barrier comprises a barrier element (5) pivotable about a horizontal axis (6), and an extensible drive mechanism (8), one end of which is anchored pivotally while the other end is connected to an erecting element (11) which co-operates with an erecting surface (12) situated be­ neath the roadway, and which is also coupled to the first end of a link (13), the other end of which is coupled to the barrier element (5) at a point (15) situated between the hori­ zointal axis (6) and the opposite end (16) thereof.

Description: A retractable road barrier. This invention relates to a retractable road barrier comprising a barrier element pivotable about a first horizontal axis. Such a road barrier is for instance used at the entrance of a parking lot to prevent unauthorized entrance. In a known device of this kind the barrier element is driven by a worm gear and slip coupling through an electromotor which has the disadvantage that the drive means are quite voluminous and relatively costly. Due to the self-braking properties of such a drive it has the drawback that, when the current source fails, the barrier cannot be retracted quickly which is particularly in case of fire and accidents very undesirable. The invention aims to eliminate these drawbacks. According to the invention the road barrier is provided with an extensible drive mechanism, one end of which is anchored pivotally about a second axis, situated beneath and parallel to the first axis.while the other end is connected to an erecting element which co-operates with an erecting surface situated beneath the roadway and which rises rewards the two axes, and is also coupled, pivoting about a third axis parallel to the first and second axes, to the first end of a link, the other end of which is coupled, pivoting about a fourth axis parallel to the other axis, to the barrier element at a point situated between the first pivot axis and the end thereof. When the road barrier is retracted the extensible drive mechanism is totally extended and lies parallel to the barrier element; the erecting element lies then at the lowest part of the erecting surface. To raise the barrier the drive mechanism is retracted so that the erecting element moves upwardly along the erecting surface and presses the barrier element upwardly by means of the link. The few parts are all simple and can be manufactured cheaply; with a small depth and short strength the barrier element can rotate over a significant angle. The simple and cheap structure makes it possible to use the road barrier for a great number of purposes, such as in self-service filling stations to prevent customers driving away without paying, protection of private and common parking places, protection of entrances, etc.. Preferably the drive mechanism is a ram actuated by a medium under pressure, preferably pressurized air. According to a preferred embodiment the elongate erecting element is connected at its center to the piston rod of the ram and is at each of the two ends pivotably connected to a link. When, according to a preferred embodiment, the erecting surface merges at its highest point into a flat portion the barrier element is locked in its raised position and need not be kept in that position by permanent pressure medium in the ram. When furthermore the erecting element is coupled with at least one abutment engaging beneath the erecting surface extension of the driving mechanism will force the barrier element downwardly so that the retracting thereof is not dependent upon gravity and cannot be impared by, e.g. dirt in its bearings Furthermore preferably a compensating spring is placed between the barrier element and the frame. The invention is elucidated on the hand of the drawings. Fig. 1 is a diagrammatic illustration of one embodiment of the invention with the road barrier element flush with the road surface; Fig. 2 shows the same embodiment with the road barrier element in the raised position. Referring to Fig. 1, reference 1 denotes a road surface, e.g. the access to a car park. The retractable road barrier is accomodated in a diagrammatically illustrated frame, the uprights of which are denoted by references 2, 3 and one longitudinal member of which is denoted by reference 4. Said frame bears the barrier element 5 via a horizontal pivot 6. At the end, the barrier element 5 bears a number of interconnected extensible closure elements 7, which screen the opening in the extended state (see Fia. 2). A pneumatic cylinder 8 is disposed beneath the barrier element 5 in the frame and is pivotable about a second and likewise horizontal pivot 9 situated beneath the pivot 6. At the end, th piston rod 10 is connected to the middle of an elongate cylindrical. erector element 11 which can rise towards an erector surface 12 anchored in the frame. The piston rod 10 passes through a central opening formed in the erector surface 12; of course two separate surfaces can be used. At each end, the element 11 projects a short distance beyond the erection surface 12 and these ends are pivotally about a horizontal pivot 14 connected to the first end of a hook-shaped link 13. The other end of each link 13 is coupled pivotably about a horizontal pivot 15 to the barrier element 5 at a point situated between the pivot 6 and the end 16 thereof. The operation is simple: when the piston rod 10 is retracted into the cylinder 8 the erector element 11 runs against erection surface 12 and presses the barrier element 5 upwards by way of the links 13. Fig. 2 shows the end position of the barrier element, in which, in the embodiment illustrated, the erector element 11 comes to rest on the horizontal extension 12a of the erecting surface 12, so that the barrier element 5 is locked in this position and does not have to be kept in the end position by maintaining medium pressure in the cylinder 8. If extension of the actuator 8 is required to cause the barrier element to retract automatically into the road surface, an abutment 17 is coupled to the erecting element 11 and engages beneath the erecting surface 12 - as illustrated in the drawings - so that when the piston rod 10 extends and the erecting element 11 moves to the right the abutment 17 abuts the underside of the erecting surface 12 and the erecting element 11 with the links 13 coupled thereto, and hence the barrier element 5, automatically move downwards. To reduce the force that the cylinder must provide, a spring 18 may be provided between the barrier element 5 and the frame, but this is not essential. It is observed that the reference numerals in the claims are not intended to rectrict the scope thereof, but are only denoted for clarification. Claims:

Claims: Claims: 1. A retractable rd barrier comprising a barrier element pivotable about a first horizontal axis, characterised by an extensible drive mechanism (8), one end of which is pivotally about a second axis (9), situated beneath and parallel to the first axis, anchored while the other end is connected to an erecting element (11) which co-operates with an erecting surface (12) situated beneath the roadway and which rises towards the two said axes, and is also coupled pivoting about a third axis (14) parallel to the first and second axes, to the first end of a link (13), the other end of which is coupled, pivoting about a fourth axis (15) parallel to the other axes, to the barrier element (5) at a point situated between the first pivot axis and the end thereof. 2. A road barrier according to claim 1, characterised in that the drive mechanism (8) is a ram actuated by a medium under pressure. 3. A road barrier according to claim 2, characterised in that the, elongate, erecting element (11) is connected at its center to a piston rod (10) of the ram (8) and is at each of the two ends pivotably connected to a link (13). 4. A road barrier according to claims 1 to 3, characterised in that the erecting surface (12) merges, at the highest point, into a flat portion (12a). 5. A road barrier ccording to claims 1 to 4, characterised in that the erecting element (11) is coupled to at least one abutment (17) engaging beneath the erecting surface. 6. A road barrier according to claims 1 to 5, characterised by a compensating spring (18) placed between the barrier element (15) and the frame.

Inventors: EIKELENBOOM, PIETER ARIE JAN
Applicants: EIKELENBOOM, PIETER ARIE JAN
Application year: 1983
Main classification: E01F13
IPC codes: E01F13