GB2504462A - Rail anchor point trolley - Google Patents

Abstract

An anchor point trolley for attachment to the rail section component of standard railway track, consisting of two vertical plates 20, 21 onto which are mounted upper runner wheels 27-30 and lower 'catch' rollers 31-34 and a shackle type connection point 42 for a lanyard or fall restraint system. The plates are connected by an adjustment screw bar 24 which, when turned, causes the plates to move together or apart in parallel due to opposing Left Hand thread on one end and Right Hand thread on the other, thereby enabling clamping by encapsulation of the unit around the rail head. A further lock device 39 drops into position resting on the upper edges of the vertical plates preventing accidental release of the device when in use.

Description

Rail Anchor Point Trolley

Field

This invention relates to a device which provides a movable anchor point mounted by screw clamping and encapsulation onto the rail component of a railway track for the attachment of a personal safety restraint lanyard or fall arrest device when working on or around railway bridges and viaducts, retaining walls and the like and in similar circumstances where encroachment into dangerous areas such as open railway lines is to be prevented.

The device is designed for use on the three main sizes of rail in use in the UK, being designated BS11OA, BS113A and UIC6O in standard form and adaptable for use on other sizes and shape profiles.

Background

There are a number of circumstances where work on railway infrastructure needs to take place adjacent to areas where there is a danger of persons falling from height or being struck by trains/machinery. In these situations there is a likelihood of serious injury or fatality. In the case of preventing a fall from height this is typically encountered when: * Replacing, repairing or maintaining hand railing and stonework/brickwork/steelwork parapets over bridges, viaducts or retaining walls.

* Installing hand railing and/or parapets over bridges, viaducts or retaining walls, where this is absent altogether.

* Working on the unprotected edge of steep embankments to carry out various railway related works such as removing overgrown vegetation and work on cabling, fencing, etc. In such circumstances Health & Safety legislation requires that a safe working environment is provided and a safe system of work is employed to achieve this. A hierarchy of risk is normally followed until the most reasonably practicable, cost effective method of preventing injury is arrived at. In the majority of circumstances it is not practicable to provide collective edge protection in the form of temporary scaffolding or fencing and it is necessary to prevent a fall rather than to rely solely on catch' systems on the basis that a fall may occur. The optimum system in such circumstances is to use trained, competent and experienced personnel, equipped with body harnesses and attached to a fixed length lanyard restraint or a fall arrest device. It is far preferable to physically prevent a fall by use of an appropriate length of tether rather than use a fall arrest device, leaving a residual risk that a harness induced injurious fall may occur and necessitate a rescue procedure.

Conventionally, the anchor point used is either the track rail, where ballast is scraped away and a lanyard looped around between sleepers or to other track components. In both cases the anchor point is fixed' and if the correct length of lanyard is used to prevent a fall then the length of work area is limited to not much beyond arm's length in either direction. When work is to progress to the next section the operative is required to return to the anchor point and establish a new one further along, which in the case of rapidly progressing work such as cleaning, painting, litter picking, etc., is grossly time consuming and inefficient. The possibility also remains that the operative may forget to re-establish the anchor point.

In the case where there is a danger of encroaching into dangerous areas, these are typically: * Working on a track that is closed to trains but adjacent ones are open to normal high speed railway traffic.

* Working on a track that is closed to trains but adjacent ones are being worked on and being used by rail mounted machinery such as ballast tampers, road-rail excavators and engineering trains.

Similarly to the situation where a fall from height is a risk, a safe environment and a safe system of work must be provided according to a hierarchy of risk. Conventional methods rely on a system known in the railway industry as separated green zone' in which the workers are separated from open lines by a specified distance with no physical barrier fence or similar. The main control is the appointment of a Site Warden who shouts a get back' warning in the event an errant worker strays too close to the open line. It is far preferable to provide a fixed tether that will allow the operative to work parallel with the open line but prevents him nearing the danger area by means of a physical restraint.

Statement of Invention

An anchor point trolley for attachment to the commonly found rail section component of standard railway track work, consisting of two vertical plates onto which are mounted upper runner wheels and lower catch' rollers and a shackle type connection point for a lanyard or fall restraint system.

The plates are connected by an adjustment screw bar which, when turned, causes the plates to move together or apart in parallel due to the opposing Left Rand thread on one end and Right Hand thread on the other, thereby enabling clamping by encapsulation of the unit around the rail head and incorporates devices to prevent accidental release of the device when in use.

Prior Art

Fall arrest systems are commonplace and rely on essentially 3 basic components -a harness, worn by an operative, a fixed' anchor point and a lanyard or similar that connects them together. The fixed' anchor point is the subject of the invention and the Prior Art described herein.

Previous technology can be categorised into 2 distinct system types -those that are sliding' such as: US Patent 5,526,896 (O'Rourke) US Patent 6,009,973 (Woodyard) US Patent 6,478,112 (Lee) and those that utilise rollers' attached to a pivoted frame such as: US Patent 4,606,430 (Roby et al) US Patent 5,325,788 (Strickland et al) In all the above cases there are technical problems that are fundamental to the anchor point performing correctly or as intended: It can be easily seen that the sliding points will inevitably bind on the rail when an attempt is made to pull them along the rail using the lanyard/tether from the point of work, requiring the operative to return to the anchor point when he wishes to move and slide the anchor point unit along by hand.

This could possibly be reduced by providing a closer fit but creates further problems where the unit encounters debris or variations in the rail section such as at welds. Generally these types are lightweight and in practice may only serve as a tether and would not tolerate the forces required to provide fall arrest in accordance with current testing and certification requirements of the industry.

The roller type units are pivoted about a central upper point and as such when placed on the rail will naturally fall into its operational position thus without checking carefully giving the false appearance that the unit is clamped' and fit to use. In order to be effective a locking pin or bolt needs to be inserted. These are separate components and are susceptible to loss and improvisation/damage/accidental removal. In the case of the Strickland et al device tests with a similar system, have shown that in use this roller layout also suffers from binding issues and is unworkable.

Other various issues with Prior Art include separate component forms, susceptibility to non-tightening or working loose in use, a requirement for tools to assemble, a lack of adjustment to adapt to various commonly encountered rail size and shape profiles or are dimensioned such that the unit is likely to foul other track components (e.g. rail to sleeper clips).

In addition, such devices need to comply with LOLER Regulations to be used in the UK, specifically BSEN 795 for a class B transportable anchor point.

Drawings An unreferenced coloured summary engineering drawing entitled Rail Safety Restraint Trolley General Arrangement' showing unlabelled versions of Figures 2, 3 & 4 below and a perspective view of the device, prepared by APP Lifting Services, a collaborator, is included for information.

Separately, Figure 1 is a sketch view of the invention mounted on a standard rail head and in normal use Figure 2 is an End View of the device in place and fully encapsulating the rail head Figure 3 is a Side View of the device Figure 4 is a Plan View of the device As shown in the drawings the device consists of a pair of generally vertical plates (20,21), perforated as a weight saving measure, onto which are mounted drilled and internally threaded solid blocks (22,23). These components are connected by a screw adjustment bar (24) that when rotated moves the vertical plates either together or apart, depending on the direction of rotation due to the Left Hand thread on one end of the screw adjustment bar and Right Hand thread on the opposite end. In use the screw adjustment bar is turned in the appropriate direction to cause the vertical plates to move towards each other in parallel. When the device is in its in use' position the side plates rest against a loose sleeve placed between the vertical plates onto the screw adjustment bar (25) to prevent over-tightening. The screw adjustment bar is also fitted with a locking arm (26) that is deployed when the device fully encapsulates the rail head (120) in the manner designed, to prevent accidental loosening.

The device encapsulates the rail head using running wheels (27,28,29,30) that are mounted onto the vertical portion of the plates and sit on top of the rail and catch rollers (31,32,33,34) mounted onto angled portions of the plates at a lower level such that the angle of the rollers generally replicate the angle of the underside of the rail head (120) but retain a nominal clearance gap when fully clamped in operational position such that effective encapsulation is achieved but the unit is free to move freely and pass any small variations in section size such as at weld positions. The rollers also are clear of the rail web (121) and foot (122) and any features usually found in these locations. The lower catch rollers are mounted on stub axles (35,36,37,38) and held with a Circlip' such that they can be removed with simple tools in the event the screw adjustment bar cannot be released in normal operation through damage, etc. A lock ring (39) drops into a horizontal position resting on the upper edges of the vertical plate components of the unit as an indication when the device fully encapsulates the rail head (120) and is fit to use. This also serves as a secondary measure in addition to the lock arm for preventing accidental unclamping of the unit in that it has to be physically lifted clear from its horizontal rest position in order to operate the adjustment screw in an expansive manner.

The device incorporates a lanyard anchor which consists of a three pin scissor action mounting unit (40) which is hinged such that it is able to move inwards and outwards with the movement of the plates. The lower hinges are attached to the plates (20,21) via the solid blocks (22,23) mounted onto them. The upper central hinge spindle (41) forms the supporting mount for the lanyard attachment ring (42) which is also able to swivel about this point.

In use, the device (220) is able to move easily along the rail head in the desired longitudinal direction (221) whilst limiting the movement of a person attached to it (222) with a safety harness (223) and fixed length lanyard (224) in a transverse direction into a dangerous area (225).

Claims (7)

1. Claims 1. An anchor point trolley for attachment, by encapsulation, of the rail head portion to the commonly found rail section component of standard railway track work, and which is able to roll along the top of the rail running surface to so as to provide a movable secure end for a personnel safety lanyard/fall restraint/harness system, consisting of, in combination, a shackle or similar ring to attach the lanyard and able to swivel towards and away from the working edge' in respect to the rail direction about the main pivot of a scissorS point hinge assembly, allowing compressive and expansive movement which is in turn attached to, a pair of generally vertical plates connected by a screw adjustment bar with locking arm onto which are mounted a number of running wheels that sit on top of the rail and a number of catch rollers' mounted onto angled portions of the plates with the angle of the rollers generally replicating the angle of the underside of the rail head but retain a nominal clearance gap when fully clamped in operational position such that effective encapsulation is achieved but the unit is free to move freely and pass any variations in section size such as at weld positions, indicated by, a lock ring indicator which drops into a horizontal position resting on the upper edges of the vertical plate component of the unit and which also serves as a secondary measure in addition to the lock arm for preventing accidental unclamping of the unit in that it has to be physically lifted clear from its horizontal rest position in order to operate the adjustment screw in an expansive manner.
2. 2. An anchor point trolley as defined in claim 1 wherein the device is a complete one component unit requiring no reliance on separate pins, keys, tools and the like to perform the designed function.
3. 3. An anchor point trolley as defined in claim 1 wherein said pair of side plate/runner wheels and low/lower catch' rollers assemblies encapsulate or release the rail head by moving towards each other or apart in parallel by means of an adjustment screw bar which possesses a left hand thread on one end and a right hand thread on the opposite end.
4. 4. An anchor point trolley as defined in claim 1 wherein the encapsulation adjustment limits are controlled by a fixed length sleeve mounted on an adjustment screw bar and between the vertical plates onto which the plates rest when fully clamped.
5. 5. An anchor point trolley as defined in claim 1 wherein the correct encapsulation adjustment is identified by means of a lock ring indicator.
6. 6. An anchor point trolley as defined in claim 1 wherein accidental loosening of the device is prevented by means of a lock ring indicator.
7. 7. An anchor point trolley according to claims 4 and 5 wherein different sizes of the sleeve mounted on the adjustment screw and lock ring indicator allows extended use of the device from current standard rail head sizes to future increased and decreased rail head sizes.