WO2002016697A1

WO2002016697A1 - Improvements relating to retractable bollards

Info

Publication number: WO2002016697A1
Application number: PCT/GB2001/003766
Authority: WO
Inventors: Mark Clement
Original assignee: Ambermist Limited; Mark Clement
Priority date: 2000-08-21
Filing date: 2001-08-21
Publication date: 2002-02-28
Also published as: AU2001282305A1; GB0020522D0

Abstract

A retractable bollard has a tubular socket (1) sunk upright into the ground, a power cable through its sealed lower end. A cylindrical intermediate housing (4) telescopes down into the socket (1) and is detachably sealed to it at ground level. The lower end (55) of the housing (4) contains a power unit (3) which is removably attached by a connector (50) to a tube (31) providing the upper part of the housing (4). This tube (31) receives a riser (2) which is telescoped up and down by a co-axial lead screw (74) driven through the connector (50) by the power unit (2). Control signals to the power unit (3) can be conveyed through the power cable or via an aerial down through the intermediate housing (4), which can be removed from the permanent socket (1) for maintenance, repair or replacement of its components.

Description

Improvements relating to Retractable Bollards This invention relates to retractable bollards. Retractable bollards for protecting parking spaces or for blocking vehicular access to drives are known. There are purely mechanical ones, which are simple and relatively cheap, but tiresome and awkward to use. They are particularly vulnerable to dirt or foreign matter getting into the tube sunk into the ground that receives the bollard. This may prevent the bollard seating properly, or impede its up and down movement. Water also tends to accumulate in the ground tube, with uncomfortable results if the bollard is simply dropped after being unlocked from its raised position.

A hydraulically operated bollard is also known, but is expensive and difficult to maintain and service.

It is the aim of this invention to enable a bollard to be remote controlled (by a driver in his car for example) and operated by an arrangement that allows easy servicing while protecting the working parts from foreign bodies and water.

According to the present invention there is provided a retractable bollard comprising: i) a tubular socket for permanent upright installation in the ground with its upper end open and substantially flush with the ground and its lower end sealed, ii) an intermediate tubular housing that can telescope into the socket and be sealingly but removably secured thereto at its upper end, iii) a power unit carried by the intermediate housing with a power supply thereto through the lower end of the socket without impairing the seal at that end, iv) a riser sealingly telescopic into the intermediate housing and operable by the power unit to move between a raised and a lowered position, in the latter with its upper end substantially flush with the upper ends of the socket and intermediate housing, and v) remote control means for conveying operating signals to the power unit.

The power unit is preferably at the lower end of the intermediate housing and coupled to a lead screw extending co-axially into the riser, being threadedly engaged therewith, and the riser is then restrained against rotation.

Conveniently the intermediate housing has upper and lower co-axial tubular sections joined by a connecting member, the riser being slidable within the . upper section and the power unit being housed within the lower section, a coupling between the power unit and the lead screw extending through the connector.

Advantageously each section is detachable from the connecting member without disturbance of the other section. Thus for maintenance the housing can be extracted and, if it is the power unit that requires attention or replacement, the lower section is detached, leaving the connecting member with the coupling secured to the lower end of the upper section.

The connector desirably has sealing means preventing ingress of water from within the upper section to within the lower section. While the riser can slide up and down through a ring seal at the upper end of the housing, that seal may deteriorate with use and allow some water to pass. But this further barrier provides a second line of defence against water getting into the power unit. Preferably there are means to sense the arrival of the riser at its lowered position and to de-energise the power supply. This can take the form of a proximity switch which opens as the riser reaches its lowered position.

It is also advisable to have means to determine the arrival of the riser at its raised position and to de- energise the power supply. Since the riser will then be at some distance from the power unit, this may be done by counting the revolutions of the lead screw, and switching off when the count reaches a predetermined number. In one form, the remote control signals are conveyed by a cable also carrying the power supply. But it is also feasible for the remote control signals to be conveyed through an aerial carried by the head of the intermediate housing. In that case the connection between the aerial in the head and the power unit may conveniently be through a spline on the interior of the intermediate housing by which the riser is prevented from rotating. In the preferred form there is a space between the lower end of the intermediate housing and the socket in which is accommodated a cable carrying the power supply. The length of this cable will enable the intermediate housing to be extracted from the socket without disconnection of the cable.

However, it may be possible for the lower ends of the intermediate housing and the socket to have a vertically mating plug and socket arrangement whereby the power supply is connected when the housing is secured but which is disconnected when the housing is extracted.

The power supply will preferably be low voltage with a buried cable to the lip of the hole made for the tubular socket. The cable will then lead down outside the socket before entering its lower end and coupling to the power unit .

As well as being responsive to remote control, there will also preferably be a safety feature that will reverse the raising of the bollard if it meets excessive resistance. It may happen, for example, that the "raise" instruction is accidentally transmitted when a vehicle is parked over the bollard. But as the bollard meets the underside of the vehicle the resistance can be detected, for example from a sudden surge of current to the motor in the power unit, and a control unit can respond to this by immediately reversing the motor.

For a better understanding of the invention, one embodiment will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a general arrangement, mostly in axial section, of a retractable bollard, Figure 2 is an elevation, half in axial section, of a ground socket,

Figure 3 is an elevation, half in axial section, of the upper portion of an intermediate housing,

Figure 4 is a detail, in cross-section, of part of that housing,

Figure 5 is an elevation, half in axial section, of a power unit in its housing,

Figure 6 is an elevation, half in axial section, of the upper end of the retractable bollard in the housed condition,

Figure 7 is an elevation, half in axial section, of a connector fitting co-axially between the power unit housing and the portion of the intermediate housing of Figure 3,

Figure 8 is a plan view of the connector of Figure 7, Figure 9 is an underneath plan view of the connector of Figure 7,

Figure 10 is a plan view of a plug of a cap that closes the lower end of the power unit housing,

Figure 11 is a plan view of a disc that is fitted to the underside of the cap of Figure 10,

Figure 12 is a side view, half in axial section, of a riser that telescopes into the intermediate housing, Figure 13 is an elevation, half in axial section, of a coupling element between the lead screw (whose lower end is shown) and the power unit,

Figure 14 is a side view, half in axial section, of a dog for coupling a motor to the element of Figure 13,

Figure 15 is a plan view of the dog of Figure 14, and Figure 16 is an underneath plan view of the dog of Figure 14.

The bollard assembly has as its basic components a permanent ground socket 1, a riser 2 which forms the actual bollard when raised, a power unit 3 to drive the riser, and an intermediate housing 4 which provides a fixed but removable liner for the ground socket and carries the power unit and houses the riser. It can be removed for servicing or repair of those items.

The ground socket 1 comprises a tube 11, conveniently of plastics (it may be standard waste pipe) with a cap 12 surrounding its upper end and a closure 13 at its lower end. The cap 12 is a concrete ring with a regular array of screw sockets 14 in its upper surface near the outer periphery, and within that array there is an annular groove 15 to receive a seal. Its inner surface has a downwardly open rebate 16 to receive the upper end of the tube 11. The upper face of this ring will be substantially flush with the ground, and it will be set in cement or concrete. The closure 13 has a cylindrical body 17 with a grooved and stepped radial flange 18 that fits the end of the tube 11 with the intermediary of a O-ring seal, the body 17 projecting downwardly. It has a lateral opening 19 to receive a gland 20 by which an electrical cable (not shown) enters a socket 21 formed within the body. This cable will carry a low voltage (24v) power supply run from a nearby domestic or office source. This needs only shallow burial, under paving slabs or bricks for example, and can be taken to the lip of the hole augured out to receive the tube 11. It will then be led down that hole outside the tube.

The intermediate housing 4 that telescopes into the tube 11 is a cylindrical assembly. Over about three quarters of its length, from the upper end, there is a cylinder 31, preferably of stainless steel. Internally, along substantially its entire length, this cylinder has a rectangular section guide rib or spline 32 attached as shown in the detail by countersunk screws 33 flush with the exterior of the cylinder 31. These are additionally bonded to guard against any ingress of water. The rib 32 could be an extrusion providing a channel 34 open to the wall of the cylinder 31 as shown in broken lines in the detail of Figure 4. The passage thus formed could accommodate an aerial as referred to again below. A flat ring 35 is welded to the upper end of the cylinder 31 to form an outward radial flange that projects beyond the cap 12. It has apertures 36 that will register with the sockets 14.

The flange 35 is clamped to the cap 12 by a thick ring 37 of the same outer diameter but greater inner diameter, forming an annular shoulder 38. Screws (not shown) are fastened down through countersunk apertures 39 to engage in the sockets 14. An externally stepped guide ring 40 fits closely within the ring 35 and the upper end of the cylinder 31, seating on the shoulder 38. It is trapped, along with a sealing ring 41 at its upper end, by a further annular ring 42, secured flush within a rebate in the ring 37 by screws 43.

At its lower end the cylinder 31 receives the reduced upper end portion of an annular connector 50, which is secured by radial screws (not shown) from outside the cylinder 31 and countersunk to be flush with its surface. Diametrically opposed screw threaded sockets 51 extend down from the upper face of the connector. The central portion of the connector has the same outside diameter as the cylinder 31 but its lower end is also reduced and in its underside there are two diametrically opposed screw- threaded sockets 52.

Before the connector 50 is fitted to the cylinder 31, its upper end is capped by a stepped bearing housing 53, whose base flange 54 is apertured to receive screws that engage the sockets 51. There are seals between the connector 50 and the cylinder 31 and between the connector 50 and this flange 54. Other elements, as described below, are assembled with the housing 52 before the connector 50 is fitted and secured.

The power unit 3 is secured to the lower end of the connector 50 and is housed in a co-axial tube 55, of the same gauge and material as the tube 31. This tube 55 is closed at its lower end by a cap 56 with two diametrically opposed apertures, and tie rods 57 enter through these apertures, extend the length of the tube 55, and screw into the sockets 52 in the underside of the connector 50. Nuts 58 on the projecting lower ends of the tie rods 56 are tightened up against a plate 59 recessed into the underside of the cap 56 and secured by screws 60 to hold this assembly together.

The cap 56 incorporates a plug 61 and the power cable which enters through the gland 20 has a socket which mates with this plug. Sufficient spare cable can coil up in the base of the tube 11, below the power unit 3, to allow the intermediate housing 4 to be withdrawn, bringing the plug/socket connection above ground. There is the alternative mentioned above of mounting a fixed socket on the closure 13, facing upwards, and arranging that the plug 61 mates with that socket when the intermediate housing is properly secured.

An electric motor 62 is mounted in the tube 55 with its drive shaft uppermost and co-axial with the housing 4. There is also a circuit board 63 to which an aerial connects and which serves to interpret the signals received and thereby control the motor. To locate this board, the upper side of the cap 56 and the connector 50 have slots 64 and 65 respectively into which the ends of the rectangular circuit board will enter. The board will thus extend lengthwise of the tube 55 just inside one of the tie rods 57. The slot 65 is open through to the top of the connector 50 so that an extension of the circuit board 63 can project into a space created between the bearing housing 53 and the top of the connector 50. This extension carries optical and magnetic sensors as described in more detail below.

While the aerial could be incorporated in the cap 12 and lead down the channel 34 to the circuit board, it is possibly more convenient to take it into the housing 4 as part of the power cable, there then being an above ground unit in the vicinity adapted to receive the bollard "raise" or "lower" instructions.

The riser 2 is another tube 70, also preferably of stainless steel, with a cap 71 plugged into its upper end and a stepped cylindrical slider 72 plugged into its lower end and secured by bonded screws. It is raised and lowered by the rotation of a co-axial screw threaded shaft 74 driven by the motor 62, the slider 72 having a vertical channel in its external cylindrical surface to accommodate the spline 32, which makes the riser non-rotatable. But the fit of the spline 32 is loose enough to allow air to pass along the channel as the slider 72 moves up and down, ensuring that there is no air compression or partial vacuum to hinder the movement of the riser.

The slider 72 has a central stepped through passage 80 reducing upwardly. A nut 81 is non-rotatably trapped in an intermediate section by a plate 82 secured by screws (not shown) through apertures 83. The shaft 74 engages the nut 81 and extends freely down through the plate 82 to terminate in a plain cylindrical tip 84 with a cross-bore 85.

This tip 84 fits into a central socket 86 in the head 87 of a mushroom-shaped coupler 88 whose stem extends co- axially down through the housing 52, in which it is surrounded by an annular seal 89 and a bearing 90. A cross-bore 91 through the head of the coupler registers with the cross-bore 85 to receive a pin (not shown) to lock the shaft 74 to the coupler 88. At about the mid-length of the stem of the coupler 87 there is an annular groove 92 for a sealing ring and towards the lower end it has a cross-bore 93 enabling it to couple to a drum-like dog 94 driven by the motor 62. This dog 94 has a co-axial cylindrical recess 95 with an outwardly stepped mouth 96 in its upper end face, traversed by a diametral slot 97. A pin (not shown) through the cross-bore 93 engages in this slot, while the lower end of the coupler 88 fits easily in the recess 95. The lower end of the dog 94 reduces at an annular shoulder 98 and a co-axial bore 99 from the lower end face opens into the base of the recess 95. This bore is traversed by another diametral slot 100, at right angles to the slot 97, which receives the ends of a pin (not shown) transversely through the drive shaft of the motor. It will be seen that this arrangement allows the motor to disconnect easily from the shaft 74 if the power unit 3 in its tube 55 is separated from the rest of the intermediate housing 4.

The cylindrical outer surface of the dog 94 has a bar code thereon which is exposed to an optical scanner 101 on the upper end of the circuit board 63, part of the slot 72 being open to the dog 94. The rotation of the shaft 74 and thus the vertical movement of the riser 2 is therefore continuously monitored. A magnet 102 in a recess 103 in the underside of the slider 72 operates a switch 104, also on the circuit board 63, and thereby serves to zero the count whenever the riser 2 is fully lowered. The bearing housing 52 will be of a material transparent to the field of the magnet .

In operation, a signal to raise the bollard received by the aerial is translated by the circuit board into energisation of the motor to rotate the shaft 74. By its co-operation with the nut 81, which is rigid with the non- rotatable slider 72, the riser 2 is moved upwardly. When a count recorded by the bar code arrangement reaches a predetermined maximum, the motor is stopped. A signal to lower the bollard results in the reverse operation.

Should the riser 2 meet with significant resistance, the increase in current drawn by the motor can be recognised by the circuit board, resulting in immediate cutting off of the supply and then reversal of the motor.

It will not be possible for someone to screw the riser 2 back down into the ground since the riser is non- rotatable, and the pitch of the thread (preferably a multi- start one) will be such that it will not be possible for someone simply to push the riser down, rotating the shaft 74 and the motor 62.

Claims

CLAIMS 1. A retractable bollard comprising: i) a tubular socket for permanent upright installation in the ground with its upper end open and substantially flush with the ground and its lower end sealed, ii) an intermediate tubular housing that can telescope into the socket and be sealingly but removably secured thereto at its upper end, iii) a power unit carried by the intermediate housing with a power supply thereto through the lower end of the socket without impairing the seal at that end, iv) a riser sealingly telescopic into the intermediate housing and operable by the power unit to move between a raised and a lowered position, in the latter with its upper end substantially flush with the upper ends of the socket and intermediate housing, and v) remote control means for conveying operating signals to the power unit.

2. A retractable bollard as claimed in Claim 1, wherein the power unit is at the lower end of the intermediate housing and is coupled to a lead screw extending co-axially into the riser, being threadedly engaged therewith, the riser being restrained against rotation.

3. A retractable bollard as claimed in Claim 2, wherein the intermediate housing has upper and lower coaxial tubular sections joined by a connecting member, the riser being slidable within the upper section and the power unit being housed within the lower section, a coupling between the power unit and the lead screw extending through the connector.

4. A retractable bollard as claimed in Claim 3, wherein each section is detachable from the connecting member without disturbance of the other section.

5. A retractable bollard as claimed in Claim 3 or 4, wherein the connector has sealing means preventing ingress of water from within the upper section to within the lower section.

6. A retractable bollard as claimed in any preceding claim, wherein there are means to sense the arrival of the riser at its lowered position and to de-energise the power supply.

7. A retractable bollard as claimed in any preceding claim, wherein there are means to determine the arrival of the riser at its raised position and to de-energise the power supply.

8. A retractable bollard as claimed in any preceding claim, wherein the remote control signals are conveyed by a cable also carrying the power supply.

9. A retractable bollard as claimed in any one of Claims 1 to 7, wherein the remote control signals are conveyed through an aerial carried by the head of the intermediate housing.

10. A retractable bollard as claimed in Claim 9, as appendant to Claim 2, wherein the connection between the aerial in the head and the power unit is through a spline on the interior of the intermediate housing by which the riser is prevented from rotating.

11. A retractable bollard as claimed in any preceding claim, wherein there is a space between the lower end of the intermediate housing and the socket in which is accommodated a cable carrying the power supply, the length of the cable enabling the intermediate housing to be extracted from the socket without disconnection of the cable .

12. A retractable bollard as claimed in any of Claims 1 to 10, wherein the lower ends of the intermediate housing and the socket have a vertically mating plug and socket arrangement whereby the power supply is connected when the housing is secured but which is disconnected when the housing is extracted.

13. A retractable bollard as claimed in any preceding claim, wherein there are means for sensing obstruction to the raising of the riser and to reverse its motion.