GB2248482A

GB2248482A - Spring system for traffic barrier

Info

Publication number: GB2248482A
Application number: GB9021540A
Authority: GB
Inventors: Kenneth Marden Henfrey
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-10-03
Filing date: 1990-10-03
Publication date: 1992-04-08
Anticipated expiration: 2010-10-03
Also published as: GB2248482B; GB9021540D0

Abstract

A tubular casing 11 contains rod 4, plates 5 and 8, compression springs 6 and 7, and a threaded adjuster 9. When connected to a pivoted traffic barrier (1, Fig. 1) the device acts to provide a weight balance for the first part of the upward movement of the barrier and a shock absorber and energy store during the final part of the upward movement. <IMAGE>

Description

COMBINED SPRING BALANCE, SHOCK ABSORBER AND ENERGY STORAGE SYSTEM FOR VERTICALLY ROTATING BEAMS SUCH AS TRAFFIC BARRIERS.

This invention relates to mechanised vertically rotating beams such as traffic barriers.

Vertically rotating beams as are used for traffic barriers are normally counter-balanced by either a weight on the opposite side of the pivot to the beam or by extension springs. The weight system gives the best balancing action throughout the movement but is bulky and adds greatly to the inertia of the system.Extension springs offer a reasonable compromise but since the effective weight of the beam is substantially proportional to the sine of the angle the beam makes with the vertical then a complicated linkage is required to match the effective weight variation of the beam. Also failure of the spring can lead to an uncontrolled downward movement of the beam.Another desirable feature of barriers of this type is that the power available to drive the beam down is limited by design so that if the beam is obstructed in its downward path it will stop before damaging the obstruction or the mechanism.

According to the present invention there is provided a single unit that closely approximates to effective beam weight during the first BO to 70 degrees of movement from the horizontal and then absorbs the excess energy of the upward drive coupled with the rapid reduction of the effective beam weight over the iast 20 or 30 degrees of upward travel to cushion the last part of the beam movement and store the energy to assist the weaker down drive power to accellerate the beam from rest. Also is incorporated a simple single action adjuster which allows for a variation in beam length and simultaneously re-positions the cushioning components.

The spring components are arranged so that they act in compression and are positioned in the unit in such a manner that failure of a spring cannot result in un-controlled descent of the beam and any broken spring parts are safely contained.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which:- Figure 1 is a diagramatic arrangement of the beam and balance unit (drive means not shown).

Figure 2 shows the components and assembly of the balance unit and adjuster.

Referring to fig. 1 of the drawing, beam 1 rotates about pivot 2 and is connected to lever 3 which is the other side of pivot 2.

Balance unit 10 is rotationly connected at 12 to lever 3 at one end and to a fixed point 13 on the supporting framework at the other end. To the left unit 10 is shown with the beam fully down and to the right with the beam fully up.

Fig. 2 shows a tubular casing 11 containing rod 4 which is terminated inside tube 11 by end plate 5 and external to tube 11 by connector 12. Around rod 4 is compression spring 6 retained between end plate 5 and the end plate of tube 11. Also contained in tube 11 is compression spring 7 retained between plate 5 and plate 8 Fod 4 plate 5 spring 6 spring 7 and plate 8 are slidably positioned in tube 11 by threaded rod 9 which terminates by connector 15 .When mounted as fig. 1 at points 12 and 13 the geometric reiationship between 12 and 13 is such that spring 6 balances the effective weight of beam 1 to within acceptable limits through about 60 degrees from the horizontal and maintains an angle between lever 3 and the centre line of unit 11 of less than 183 degrees with the beam fully up. The dimensions of rod 4 ana tube 11 are such that beyond an upward travel of beam 1 through about 60 degrees plate 5 makes contact with spring 7 and compresses it against plate 8, this absorbs the remaining energy cf beam 1. The energy now stored in spring 7 is available to accellerate beam 1 from its stationary vertical position when the drive is energised to beam 1 down. Since the distance between 12 ana 13 remains constant for any given beam position rotation of tube 11 about threaded rod 9 will vary the compression of spring 6 and thus adjust for varying beam lengths and at the same time reposition plate 8 and spring 7 so that the relative positions of springs 6 and 7 remain constant. It can be seen from fig.2 that should spring 6 break no catastophic action will follow since all parts are retained in tube 11 and the broken ends of spring 6 will abut and prevent uncontrolled descent of beam 1.

Claims

1 A single easily adjustable unit comprising a spring balance a shock absorber and energy store for vertically rotating beams such as traffic barriers.

2 A unit as claimed in claim 1 whereby all the spring components are contained in the event of breakage.

3 An adjustable unit comprising spring balance, a shock absorber and energy store substantially as described herein with reference to figs. 1 and 2 of the accompanying drawing.

3 A unit as claimed in claim 1 and claim 2 whereby the springs are located and operated in such a manner that spring failure will not result in uncontrolled descent of the beam.