Patent Description:
Slab track systems are usually installed according to either the "top-down principle" or the "bottom-up principle". In the "top-down" method, firstly a concrete slab is poured along the course where the track will be installed. Rails are then laid down on the slab and may be assembled, or may already have been pre-assembled, with other superstructure elements (fastenings, sleepers or supporting blocks) to form a track panel. The rails are then raised to their approximate intended positions using a series of hydraulic jacks. Adjustment plates are then placed under the rails and include a rail supporting portion which abuts the underside of the foot of each rail at intervals to support the rails. Each adjustment plate is supported on a pair of threaded spindles which engage with threaded holes provided in the adjustment plate. By rotating the spindles, the height of the adjustment plate, and hence the height of the rail, can be adjusted. The support plates generally also allow for lateral positional adjustment of each rail.

In the case of a rail system with sleepers or crossties, these sleepers or crossties are attached prior to setting the positions of the rails and hence the spacing of the rails is set by the attached sleepers. In the case of a system with no sleepers, then temporary gauge holders may be used to set the correct spacing of the rails.

A survey vehicle or cart is set onto the rails which are to be adjusted into their final positions. The survey vehicle includes GPS or other positioning detection systems. In the case of installing rails inside a tunnel then survey points or reflectors located at known locations alone the insides of the tunnel walls may be used to infer the precise location of the survey vehicle, and hence enable fine adjustment of the height and lateral positions of the rails by way of the adjustment plates.

After the fine adjustments of the rails are completed, formwork is installed as necessary before concrete is poured to set the rails in their final positions. After the concrete has set the spindles are removed from the adjustment plates, and the adjustment plates and any gauge holders are removed. The holes in the concrete left by the spindles are filled.

The "bottom-up" principle differs from the top down principle in that the initial concrete pour is made to bring the top surface of the slab to an acceptable design level. Then the rails are set on adjustment plates in the same way as for the "bottom-down" method, but using spindles of a shorter length. The rails of the track are affixed to the slab using fasteners using resilient plastic pads of appropriate thickness between the slab and the underside of the fasteners to yield an installed track with rails set at their correct heights. The adjustment plates attached to the rails at intervals between the fasteners are used to fine tune the locations of the rails whilst the plastic pads are inserted and before bolts are locked down to affix the fasteners to the slab.

In existing slab track installation systems, the adjustment plates are installed by a team of two people. Two people are typically required to carry out the task of positioning the adjustment plates under the foot of each rail and making adjustments using the plates to bring the rail to its intended final position.

Examples of prior art can be found in documents <CIT>, <CIT> and <CIT>.

The present invention provides a slab track adjustment device as defined in the claims. Suitably, the slab track adjustment device includes: a rail support portion for supporting a rail; at least two height adjustment apertures for receiving height adjustment spindles to adjust the effective vertical position of the rail support portion; a lateral adjustment means to adjust the horizontal position of the rail support portion; a removable locking piece which includes a peg and an upstanding prong and wherein the rail support portion is engageable with the foot of the rail so that the adjustment device can hang from the foot of the rail during the process of installing the adjustment device.

The at least two height adjustment apertures may be internally threaded.

The adjustment device may include a baseplate.

The rail support portion may be rotatably mounted in the device.

The rail support portion may be rotatably mounted to spindle.

The lateral adjustment means may include a threaded rod which cooperates with a threaded hole which is associated with the spindle.

The threaded rod may include formations provided at either end of the rod to enable rotational adjustment of the rod.

The locking piece may further include a spacer formation for setting the cant of the rail.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:.

Referring to <FIG>, a slab track adjustment device <NUM> is shown. The device <NUM> includes a baseplate <NUM> which is provided with two height adjustment apertures in the form of two internally threaded holes being the bores of two hex nuts <NUM>, <NUM> which are welded to baseplate <NUM>. The bores (22a, 24a best seen in <FIG>) of nuts <NUM>, <NUM> receive height adjustment spindles in the form of M30 threaded spindle rods <NUM>, <NUM>. In use the lower ends of the spindle rods rest against a concrete slab. The hex formations <NUM>, <NUM> at the top of the spindle rods can be rotated using a suitable power tool which effects an adjustment of the vertical position of the baseplate by way of the nuts <NUM>, <NUM> travelling upwards or downwards on their respective spindles. A spirit level gauge <NUM> provides a visual indication to enable an operator to make the baseplate horizontal, by rotation of an appropriate spindle rod <NUM>, <NUM>.

Device <NUM> further includes a rail support portion in the form of support plates <NUM>. The support plates <NUM> are attached together by a spacer <NUM> (best seen in <FIG>) and act to support a rail in use to enable the position of the rail to be adjusted. The support plates <NUM> are rotatably mounted to a horizontally oriented spindle <NUM> which is slidably attached to the baseplate <NUM> by two clamp brackets <NUM>.

As best seen in <FIG>, a lateral adjustment means is provided to allow for adjustment of the horizontal position of the support plates <NUM> (and thus the horizontal position of a rail which is supported on the support plates) in the form of a threaded rod being the shaft of an M14 hex head screw <NUM> which is of a length of approximately <NUM>. The shaft <NUM> of screw <NUM> cooperates with a threaded hole <NUM> provided at the mid-point along the length of spindle <NUM>. An M14 hex nut <NUM> is keyed to the free end of hex screw <NUM> which is mounted between bushes <NUM> provided at either end of baseplate <NUM>. In this way, the screw <NUM> is retained to the baseplate <NUM>, and can be rotated by use of an appropriate power tool to act on either end of the hex screw <NUM>. Rotation of the hex screw <NUM> causes lateral movement of the spindle <NUM> between its limits of travel which are dictated by the lengths of the spaces provided within the clamp brackets <NUM>. Of course, the direction of travel of the spindle <NUM> will be determined by the direction of rotation of the hex nut <NUM>, either clockwise or anticlockwise.

Referring now to <FIG>, additional components of the adjustment device <NUM> are shown. A removable locking piece <NUM> is used to retain the support plates <NUM> in association with a rail by engaging with the foot of the rail. Locking piece <NUM> is engageable with one of the support plates <NUM> by sliding locking piece <NUM> so that peg <NUM> (just visible in <FIG>) slides into aperture <NUM>. The locking piece <NUM> is used to "trap" the foot of a rail between the upstanding prongs <NUM> of the support plates and the upstanding prong <NUM> of the locking piece (as seen in <FIG>).

Referring again to <FIG>, locking piece <NUM> includes a spacer portion <NUM>. When attached to the support plates <NUM> of the adjustment device <NUM>, the spacer portion <NUM> sits between the underside of the foot of the rail and the upper surface of the support plates <NUM>. The thickness of the spacer portion <NUM> dictates the cant of a rail which is being adjusted using the device <NUM> in conjunction with a gauge holder arrangement. A gauge holder is used when installing and adjusting rails which are not fitted to bearers/sleepers.

As shown in <FIG>, the gauge holder arrangement includes an optional gauge bracket <NUM> which is used in conjunction with each adjustment device <NUM>. The gauge bracket are attached to the support plates <NUM> of an adjustment device by way of four screws <NUM> which are inserted through apertures <NUM>. When attached, the web <NUM> of the gauge bracket lies at a fixed <NUM> degree angle with respect to the upper faces of the support plates <NUM>.

Now referring to <FIG>, two adjustment devices <NUM> are shown in use to align two rails <NUM>, <NUM> which form a track. The track is to be installed flat and a <NUM>/<NUM> inwardly directed cant is to be applied to each rail and no bearers are to be used with the rails.

Prior to the installation of the rails, a concrete slab <NUM> is poured along the course of the track. After the concrete slab <NUM> has set, the rails <NUM>, <NUM> are laid out in their approximate positions and are raised up to just below their approximate installation height using hydraulic jacks (not shown). Adjustment devices <NUM> are then attached to the feet of the rails <NUM>, <NUM> in pairs spaced apart at intervals along the rails (one of these pairs of adjustment devices <NUM> is shown in <FIG>).

Each adjustment device can be attached in turn to the rails in a two-handed operation carried out by one person. An adjustment device is taken in one hand and is brought into position by raising it up under the rail so that the support plates <NUM> press against the underside of the foot of the rail, and the upstanding prong <NUM> of the support plates <NUM> encircle the inside edge of the foot of the rail. Then, taking a locking piece in the other hand, the locking piece is attached to the adjustment device by sliding peg <NUM> into aperture <NUM> so that spacer portion <NUM> slides between the underside of the foot of the rail and the upper surfaces of the support plates <NUM>, and the upstanding prong <NUM> of the locking piece <NUM> encircles the outer edge of the foot of the rail. The adjustment device is thereby engaged with the rail by the locking piece <NUM>, and can hang from the foot of the rail. With the locking piece <NUM> attached, the person can therefore remove their hands and leave the adjustment device hanging from the rail and move on to attach the next in the series of adjustment devices.

In the installation illustrated in <FIG>, no bearers or sleepers are attached to the rails <NUM>, <NUM> and so a gauge holder arrangement is used. The gauge holder arrangement includes a gauge bar <NUM> which is formed from two identical end pieces <NUM> which are threadedly received into each end of the bore of a centre piece <NUM>. The effective length of the gauge bar <NUM> can be adjusted for use in installing tracks of different gauges. The gauge bar <NUM> is adjusted by rotating the ends <NUM> with respect to the centre piece <NUM> to achieve the desired overall bar length for the particular desired gauge. The rotational positions of the end pieces <NUM>, and hence the overall length of the bar <NUM>, are then fixed by tightening locknuts <NUM>.

The end pieces <NUM> each have enlarged circular flanges at their outer ends. Each end piece is fitted to a respective gauge bracket <NUM> by sliding the end of the rod into an open ended <NUM> provided in the web <NUM> of each gauge bracket <NUM> (shown in <FIG>). The flange abuts the inside surface of the web <NUM> and the gauge bar end is fixed in place by tightening a locknut <NUM> provided on each end piece <NUM> against the outer surface of the web <NUM> of the gauge bracket <NUM>. The gauge holder arrangement therefore holds both attached adjustment devices apart by a set distance, and also sets the angular orientation of the support plates so that the upper flat faces of the support plates lie in the same plane.

When all of the adjustment devices <NUM> and the gauge holder arrangements are in place along the stretch of track being adjusted, then fine adjustments are made to track to set the rails in their final installed positions. These adjustments are made in a somewhat conventional manner, using the output of a survey vehicle, such as a cart located on the rails, to verify that the rails are in their correct positions along the stretch of track.

The vertical positions of the rails <NUM>, <NUM> are adjusted using spindles <NUM>, <NUM>. These are rotated in either direction to adjust the vertical position of the rail, and at the same time to ensure that the baseplate <NUM> of each adjustment device is horizontal by inspecting each spirit level <NUM> located on each adjustment device <NUM>. The horizontal positions of the rails <NUM>, <NUM> are adjusted using the hex screw <NUM> provided on each adjustment device <NUM>.

The adjustment procedure is complete when it is deemed that the rails <NUM>, <NUM> are in their correct final positions within an allowable tolerance. The flat faces of the support plates will now be lying in a plane that is parallel to horizontal line A and a <NUM>/<NUM> cant has been applied to each rail by virtue of the spacer portions <NUM>.

Appropriate formwork for a second stage of concrete pouring is then installed. Concrete is then poured around the rails to set the rails in position in a usual fashion. The formwork is configured so that the adjustment devices <NUM> do not become embedded in the second stage concrete pour. It is acceptable for the lower ends of spindles <NUM>, <NUM> to become embedded in the second stage concrete pour.

After the second stage concrete has set the spindles are removed by rotating them with a power tool which releases them from being bound by the concrete and allows them to be removed upwardly from the associated threaded holes in the baseplates <NUM>. With the spindles <NUM>, <NUM> removed, the adjustment devices can then be removed by removing the locking piece associated with each adjustment device and sliding the adjustment device out from under the rail. The adjustment devices <NUM> can be re-used for adjusting a subsequent stretch of track. The holes left by the spindles are filled and the rail installation is complete.

Referring to <FIG>, a modified version of the arrangement of <FIG> is shown in which is being used to install a track which is itself canted with a vertical offset of <NUM> between the height of each rail. A <NUM>/<NUM> cant is also applied to the rails. All of the components used are the same as those seen in <FIG>. When installing the track shown in <FIG>, the adjustment device <NUM> attached to the rails <NUM>, <NUM> are adjusted to give the required vertical heights of each rail, according to measurements made by the survey cart (not shown). It is to be noted that baseplates of the adjustment devices <NUM> themselves still lie in horizontal planes. The support plates <NUM> pivot on their respective spindles <NUM> to accommodate the required angular orientations of the rails.

If flat rails are required to be installed, such as may be found in the vicinity of turnouts or other track crossing sections, then a modified locking piece is used. Referring to <FIG>, a modified version of <FIG> is shown in which the locking piece has been replaced with a flat track style locking piece 50a. Locking piece 50a differs form the locking piece <NUM> seen in <FIG> in that it omits the spacer portion. When locking piece 50a is used, the foot of the rail sits flush with the upper surfaces of the support plates <NUM>. In all other respects, the components shown in <FIG> are identical to those seen in <FIG>.

Whilst the above described method involved a "top-down" slab track installation, embodiments of the invention can also be used in a "bottom-up" style of installation. Indeed, the slim profile enabled in adjustment plates according to the invention, it makes them particularly suitable for "bottom-up" installations because they can be removed easily from under the rail after the adjustments process has been completed.

It can be seen that embodiments of the invention provide at least one of the following advantages:.

Claim 1:
A slab track adjustment device (<NUM>) including:
a rail support portion (<NUM>) for supporting a rail;
at least two height adjustment apertures (<NUM>, <NUM>) for receiving height adjustment spindles (<NUM>, <NUM>) to adjust the effective vertical position of the rail support portion (<NUM>);
a lateral adjustment means <NUM> to adjust the horizontal position of the rail support portion (<NUM>); characterised in that
the adjustment device further includes a removable locking piece (<NUM>) which includes a peg (<NUM>) and an upstanding prong (<NUM>);
the rail support portion (<NUM>) includes an aperture (<NUM>) located in a side face of the rail support portion (<NUM>);
wherein the rail support portion (<NUM>) is engageable with the foot of the rail by attaching the locking piece (<NUM>) to the rail support portion (<NUM>) by sliding the peg (<NUM>) into aperture (<NUM>) so that the upstanding prong (<NUM>) of the locking piece (<NUM>) encircles the outer edge of the foot of the rail so that the adjustment device (<NUM>) can hang from the foot of the rail during the process of installing the adjustment device.