GB2421974A

GB2421974A - Operating mechanism for automatic retractable bollard

Info

Publication number: GB2421974A
Application number: GB0500219A
Authority: GB
Inventors: Kenneth Marden Henfrey
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-01-07
Filing date: 2005-01-07
Publication date: 2006-07-12
Also published as: GB0500219D0

Abstract

The operating mechanism, for use with bollards such as are used to protect parking areas, delineate traffic lanes etc., comprises a drive motor 1 and a flexible connector 10 that requires no components to be situated in the space below the bollard 7. There is preferably no rigid connection between the drive motor and the bollard. The bollard is preferably located within a tube with a square cross-section, with the corners of the tube including guides 8 for the post which are flexibly mourned to deflect minor collisions without damage. The bollard is preferably locked in the up position by a solenoid such that the bollard will drop in the event of power failure. A thermostat may be included which can be set to as to energise the solenoid when the temperature falls towards freezing in order to prevent ice forming that might inhibit the bollard. Vents may be provided in the upper part of the bollard to prevent water being sucked into the mechanism due to the pressure drop caused by the rising bollard.

Description

IMPROVED AUTOMATIC RETRACTABLE BOLLARD

This invention relates to an improved automatic retractable bollard.

Bollards of this type are well known and are used to protect parking areas, to delineate temporary traffic lanes and provide security against vehicles trying to penetrate sensitive areas.

In general they consist of a cylindrical metal tube embedded in the ground and another cylindrical metal tube with a cover at the top called the bollard, loosely fitting inside the embedded tube. The bollard is able to slide up and down in the embedded tube and when in the raised position has approximately two thirds of its length above ground the remaining third remaining inside the embedded tube to provide stability.

It is usual for the bollard to be raised and lowered by either a pneumatic or hydraulic ram although it may be stipulated that the bollard should be able to retract under its own weight in case of power failure. With this type of construction water dirt and other contaminates are drawn into the space between the two tubes and can inhibit the sliding operation.

Whatever type of ram is used it is positioned directly beneath the bollard and in an attempt to reduce the depth of the hole required may extend into the part of the bollard above ground when raised. This means that any collision with the bollard resulting in enough force to seriously damage the bollard will almost certainly also cause damage to the operating system. Also some specifications call for the above ground section of the bollard to shear off rather than continue as a dangerous obstacle in the path of vehicles.

Apart from hydraulic and pneumatic operation it would often be an advantage if an electric operating system could be used but if situated under the bollard the components could easily be damaged by the ingress of water and slurry and would be difficult to access for maintenance.

According to the present invention there is provided a bollard operating system that could use an electric motor and gearbox and is not positioned below the bollard, The motor and gearbox are situated in the highest possible position and therefore in the area of least contamination and in an area of easy access for maintenance. There is no rigid connection between the motor unit and the bollard and no damage to the bollard can be transmitted to the operating system. Also instead of a round tube embedded in the ground a square section is used which very much reduces the possibility of contaminates inhibiting the sliding action and provides space in the corners for guides and a connection between the bollard and the drive unit.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 shows the mechanism in plan Figure 2 shows the mechanism in elevation with the bollard down Figure 3 shows the mechanism in elevation with the bollard raised.

Figure 4 illustrates the overload switching system.

Figure 5 illustrates the connecting means between the two parts of the bollard Figure 6 illustrates the construction of the flexible guides.

Referring to the drawing the mechanism consists of a motor gearbox I the final drive shaft 2 which carries the toothed pulley 3 and is suspended from bearings 4 which are attached to cover plate 5. as shown in Fig 1. Also shown in Fig 1 are the square tube 6 the bollard 7 the flexibly mounted guides 8 and the constantly rated solenoid 9. The same components are shown in Fig 2 together with the toothed belt 10 passing over the pulley 3 and connected to one of the guides 8 the guide 8 opposite this one being as high as possible to counter the torque generated by the belt being connected off the centre line of the bollard.7. It can be seen that if the pulley 3 is rotated anti clockwise the bollard 7 will rise and if the driving force ceases or is reversed then the bollard 7 will return to the down position by gravity. Fig 3 shows the same components with the bollard 7 in the raised position and in this position a switch not shown will disconnect the drive and energise solenoid 9 the plunger of which will latch the bollard up. De energising the solenoid 9 will cause the bollard to descend by gravity.

Figure 4 shows the motor gearbox 1 final shaft 2 pulley 3 and bearings 4 also shown are switch 11 operating arm 12 attached to 1, adjusting screw 13 and spring 14. In this illustration the pulley 3 is shown with clockwise rotation to raise the bollard. It can be seen that if sufficient force is applied to to stop the bollard rising then the whole motor gearbox 1 and operating arm 12 will rotate in an anti clockwise direction to compress spring 14 and at a chosen spring setting will actuate switch 11 which with suitable circuitry will de energise the motor and allow the bollard to descend by gravity. Also shown are the vents 21.Fig. 5 shows a bollard 7 constructed in two separate sections the top section being the part that will be above ground level having a flange 15 rigidly attached and a matching flange 16 at the top of the lower section. The two sections are attached to each other by a bolt 17 which is waisted to ensure it breaks at that point. Bolt 17 is also drilled through its length to take a multi strand steel cable 18 which has a retaining nipple each end. Cable 18 will keep the bollard 7 from departing its position and rolling into the path of other vehicles if detached by a collision.

Fig. 6 shows the construction of the flexible guides. The housing 19 is rigidly attached to the bollard 7 and contains a length of low friction plastic rod such as PIFE 20 slidably contained within the open end. Behind the plastic rod is a rectangular rubber section 21 which deforms if pressure is applied to the rod 20 thus allowing some lateral movement of bollard 7 in the square tube 6 before metal to metal contact is made.

Although in the example only an electric power unit is described it is obvious the the electric unit could be replaced by a pneumatic or hydraulic motor. Also a toothed belt and pulley is described since it is the most resistant to adverse conditions but it is obvious that a sprocket and chain or a cable and drum could be used.

Claims

I An operating mechanism for automatic retracting bollards comprising a drive motor and a flexible connecter that requires no components to be situated in the space below the bollard.
2 A mechanism as claimed in claim I wherein there is no rigid connection between the drive motor and the bollard.
3 A mechanism as claimed in claims 1 and 2 wherein the tube embedded in the ground is of square cross section.
4 A mechanism as claimed in claims 1 2 and 3 wherein the corner sections of the square tube act as guides to prevent metal to metal contact between the bollard and the tube wall during raising and lowering operations and also provides space for the motor bollard connection.
A mechanism as claimed in claims 1 2 3 and 4 wherein the guides are flexibly mounted so that the bollard can be deflected by minor collisions without damage.
6 A mechanism as claimed in claims 1 2 3 4 and 5 wherein the motor mounting is so arranged that at any load pre determined by an adjustable spring selling the whole motor assembly will rotate about the final drive shaft and operate a switch to reverse the bollard raising operation.
7 A mechanism as claimed in claims 1 2 3 4 5 and 6 wherein the bollard is locked in the up position by the plunger of a constantly rated solenoid so that on power failure the bollard will fall by gravity.
8 A mechanism as claimed in claim 7 incorporating a thermostat which can be set so as to energize the solenoid when the outside temperature falls towards freezing thus using the solenoid as a heater to prevent ice forming that might inhibit operation of the bollard.
9 A mechanism as claimed in claims 1 2 3 4 5 6 7and 8 wherein the bollard consists of two separate sections the section above ground in the raised position being mounted in such a manner that it will detach at a predetermined load but will be restrained from rolling into the path of other vehicles.
A mechanism as claimed in claim 9 wherein there are provided vents in the upper part of the bollard to prevent water being sucked into the mechanism due to the pressure drop caused by the rising bollard.
11 A mechanism substantially as described herein with reference to Figures 1 2 3 4 5 and 6 of the accompanying drawing.