[0001] This invention relates to a levelling system for a rail, and more particularly relates
to a system for levelling rails of the type used in mobile shelving sytems or other
storage systems.
[0002] Shelving systems can carry very high total loads which may be of the order of several
hundred tonnes. These loads must be transferred to the structure in which the shelving
system is situated, and the structure will deform to some extent in response to the
loads.
[0003] It is difficult if not impossible to predict the exact response of a structure to
an imposed load, particularly if the load is itself unpredictable as may be the case
in a shelving system. The implications of this may be serious, particularly where
the shelving system is of the mobile type in which shelving units are movably mounted
on rails or the like to minimise aisle space requirements. In particular, the floor
upon which the rails are mounted (and therefore the rails themselves) may sag or otherwise
deform in response to the load exerted by the shelves. This may interfere with the
correct operation of the shelving system, causing the mobile shelving units to move
towards the lowest point of the rails. This movement may cause injury to an operator,
can damage the drive system and is generally inconvenient in use.
[0004] It will be clear that the rails of a mobile shelving system must be maintained substantially
level. under load if the system is to operate correctly. In existing levelling arrangements,
the rails are levelled during installation by means of jacks acting upon the floor
to which the rails are attached. These arrangements have several drawbacks. For instance,
the jacking force is usually borne by other parts of the structure, generally the
floor below the floor being levelled, which causes further unpredictable deformation.
More seriously, in existing arrangements it is impossible to make adjustments after
installation and therefore there can be no compensation for the deflection which will
occur as the shelves are loaded.
[0005] An object of this invention is to provide a rail-levelling system which overcomes
or mitigates the disadvantages of existing arrangements.
[0006] According to one aspect of this invention a storage system for fitment to a structure
comprises movable storage units mounted on guide rails, wherein the guide rails are
attached to the structure by means including a plurality of support units which are
independently adjustable to vary the distance between the guide rail and a datum point
on the structure.
[0007] According to another aspect of this invention a system for levelling a guide rail
includes a plurality of adjustable support units wherein the support units act on
a carrier rail which supports and reinforces the guide rail.
[0008] This invention also provides a system for levelling a guide rail, the system comprising
a plurality of support units for supporting the rail relative to a structure, each
support unit including at least two adjustment/support means whereby the height of
the guide rail relative to the structure is adjustable and maintained in an adjusted
position before and after loading and at least one of the adjustment/support means
is located on either side of the guide rail.
[0009] According to a further aspect of this invention a tool for simultaneously turning
two or more threaded members includes a main pivoting member operable to turn at least
one auxiliary pivoting member connected thereto, and has connecting means, associated
with the pivoting members, for engagement with the threaded members, wherein two or
more connecting means are provided and at least one connecting means is associated
with an auxiliary pivoting member.
[0010] It is preferred that two auxiliary pivoting members are provided. The pivoting members
are suitably gear wheels, and the or each auxiliary gear wheel is suitably meshed
with the main gear wheel. The connecting means are preferably hexagonal studs for
engagement within hexagonal recesses on the threaded members.
[0011] Embodiments and aspects of this invention will now be described, by way of example,
with reference to the accompanying drawings in which:
Figure 1 is a cross-sectional view of an existing rail arrangement;
Figure 2 is a cross-sectional view of one embodiment of a rail jack/support assembly
in accordance with this invention;
Figure 3 is a side view of a carrier rail shown in Figure 2;
Figure 4 is a plan view of a carrier plate shown in Figure 2;
Figure 5 is a cross-sectional view of a jack screw shown in Figure 2;
Figure 6 is a cross-sectional view of a jack barrel shown in Figure 2;
Figure 7 is a plan view of a base plate shown in Figure 2;
Figure 8 is a schematic plan view of an adjustment tool according to this invention,
and
Figure 9 illustrates a manually operable mobile storage unit mounted on a system of
parallel guide rails.
[0012] Figure 1 of the drawings shows a typical existing rail arrangement for a mobile storage
system, in which a guide rail 10 is attached to a floor member 12 by means (including)
a screw 14 or the like. It will be clear that the floor will deform with the guide
rail as the storage system is loaded, and in some structures the floor may deflect
by as much as 20mm or more under full load conditions. Correct levelling of the rail
depends upon levelling of the floor by means such as the aforementioned jacks.
[0013] Referring now to Figure 2 of the drawings, a preferred embodiment of this invention
is shown in the form of a guide rail jack support assembly. It is envisaged that a
plurality of these assemblies will be used to support and adjust each rail, equally
spaced apart with a pitch of about 600mm.
[0014] As shown in Figure 2 the guide rail 10 is supported by a square box-section carrier
rail 16 which extends along substantially all of the length of guide rail 10. A length
of carrier rail 16 is shown in Figure 3 and includes a plurality of equally-spaced
rectangular slots 18 which extend through the side walls of the carrier rail 16. The
slots 18 of one side wall correspond with the slots 18 of the other side wall to form
pairs of oppositely disposed slots.
[0015] Each pair of oppositely disposed slots 18 receives a transverse rectangular carrier
plate 20 which extends through the carrier rail 16 as shown in Figure 2. The carrier
plate 20 is shown in plan view in Figure 4 and includes a pair of circular holes 22
one located towards each end of the plate. The holes 22 each receive a jack screw
24, one of which is shown in detail in Figure 5. The jack screw 24 has a lower portion
26 threaded with a right-hand thread and an upper plain cylindrical portion 28 which
is dimensioned for location within a hole 22 of the carrier plate 20. The upper 28
and lower 26 portions are separated by a radially-extending flange 30, which constitutes
a bearing surface for the carrier plate 20 as shown in Figure 2.
[0016] Each jack screw 24 is supported by a cylindrical jack barrel 32 (shown in detail
in Figure 6), the threaded lower portion 26 of the jack screw being threadedly engaged
within a correspondingly threaded recess 34 in the top end of the jack barrel. The
jack barrel 32 may be of any appropriate length to suit a particular application.
[0017] The bottom end of the jack barrel 32 has a spigot 36 for location in a rectangular
base plate 38, the base plate being provided with at least one hole 40 (as shown in
Figure 7) for receiving the spigot. The base plate 38 is securely attached in a fixed
position relative to a datum level of the floor structure, and the jack barrel 32
is welded to the base plate 38 as shown in Figure 2. The base plate 38 is enlarged
relative to the carrier plate 20 and the jack barrels 32 to spread the load it bears
over a large area of the floor structure.
[0018] Referring to Figures 5 and to the jack barrel 32 as shown in Figure 6, each jack
screw 24 has a hexagonal recess 42 at its top end for receiving an Allen key or the
like. The jack screw 24 may be turned by means of the Allen key, and this causes the
jack screw to move along its axis by virtue of the threaded engagement with the jack
barrel 32. This movement is reflected by the carrier plate 20 and by the carrier rail
16, and therefore also by the guide rail 10. Accordingly, turning the jack screw 24
effects relative movement between the guide rail 10 and the base plate 38 and this
can be used to adjust the height of the guide rail relative to the floor datum level.
[0019] Each jack screw 24 is also provided with an axially-extending internal passage 44
which is threaded with a left-hand thread and which extends from the hexagonal recess
42 to the bottom end of the jack screw. The passage 44 is for receiving a capping
screw 46 as shown in Figure 2. The capping screw 46 has a flat head portion 48 for
flush location within a floor recess 52 and a threaded stem portion 54 for engagement
within the passage 44. The head portion 48 may be provided with a recess such as a
slot 56 to facilitate turning of the capping screw 46.
[0020] The capping screw 46 performs two main functions. Firstly, it prevents dirt from
blocking the recess 42, which would otherwise be a problem given the unit's floor
location. Secondly, the capping screw acts to lock the jack screw against unwanted
rotation by virtue of the conflict between the capping screw's right-hand external
thread and left-hand internal thread. As will be clear, the same effect can be obtained
if the respective threads are both reversed so long as the threads remain mutually
opposed.
[0021] It is generally advantageous when adjusting the height of the guide rail 10 to be
able to turn both jack screws 24 of a pair by the same amount so as to prevent unwanted
twisting about the axis of the carrier rail 20. As shown in Figure 8, this invention
provides a tool which allows simultaneous and identical adjustment of jack screws
on either side of the carrier rail 20. The tool includes a handle 58 which is operable
to turn a central gear wheel 60 about an axial pivot. The central gear wheel 60 meshes
with a pair of outer gear wheels 62 whose centres are spaced to correspond to the
spacing between two jack screws. The outer gear wheels 62 have associated co-axial
hexagonal heads 64 shaped to fit into the recessses 42 in the jack screws, whereby
both jack screws may be turned simultaneously by operating the handle 58.
[0022] The respective sizes of the central 60 and outer 62 gear wheels may be selected to
give a required mechanical advantage so as it make it easier to turn the jack screws.
The handle 58 could of course be replaced with a shaft or the like if it was decided
to employ a motor to turn the jack screws.
[0023] As will be clear to those skilled in the art, this invention provides a means for
levelling guide rails which enjoys substantial advantages over known arrangements.
For instance, the carrier rail 16 helps to spread the reaction force of the jack/support
assemblies so that the guide rail 10 remains substantially flat under load even if
the jack/support assemblies are wrongly adjusted in relation to one another. Moreover,
the provision of height adjustment means spaced widely apart on either side of the
carrier rail 16 helps to prevent twisting of the guide rail 10 and allows for some
compensatory adjustment if twisting should occur.
[0024] A major advantage of this invention stems from the fact that the height adjustment
means are situated between the main floor structure and the carrier rail 16. This
means that the main floor structure does not need to be moved to level the carrier
rails, which avoids the need for jacking floors. The floor surface panels 66 shown
in Figure 2 rest upon the carrier plate 20 and are therefore automatically levelled
as the rails are levelled. The adjustment means are readily accessible and easily
adjustable, which allows ready levelling of the rails when required. More particularly,
this invention makes it feasible to level the guide/carrier rails after the load has
been applied for the first time or after there has been any significant variation
in the load. Levelling may be performed without removal of floor panels and with little
disruption of the shelving installation or the building in which it is situated.
[0025] In general this invention greatly simplifies the levelling process, which minimises
the skill requirements, and the cost, of levelling. It is envisaged that this invention
will allow the fitment of mobile shelving storage systems to many more buildings than
had previously been possible.
[0026] Figure 9 illustrates a manually operable mobile storage units S mounted on a system
of parallel guide rails. Each storage unit 5 is movable on a plurality of parallel
guide rails 10 manually by means of a chain/sprocket drive C which in turn drives
a shaft X drivingly connected to wheels W in a manner known per se.
1. A storage system for fitment to a structure, comprising movable storage units mounted
on guide rails, wherein the guide rails are attached to the structure by means including
a plurality of support units which are independently adjustable to vary the distance
between the guide rail and a datum point on the structure.
2. A system for levelling a guide rail, including a plurality of adjustable support
units, wherein the support units act on a carrier rail which supports and reinforces
the guide rail.
3. A system for levelling a guide rail, comprising a plurality of support units for
supporting the guide rail relative to a structure, each support unit including at
least two adjustment/support means whereby the height of the guide rail relative to
the structure is adjustable and maintained in an adjusted position before and after
loading, and at least one of the adjustment/support means is located on either side
of the guide rail.
4. A storage system for fitment to a structure, the system comprising at least one
storage unit mounted for movement upon at least two parallel guide rails supported
by the structure,
a carrier rail associated with each guide rail and extending longitudinally of the
guide rail for supporting the guide rail,
a plurality of support units disposed at different locations longitudinally of each
carrier rail, each support unit including at least two adjustable support means with
at least one of the said support means located on each side of the carrier rail for
varying the distance between the guide rail and a datum on the structure,
a bridging member bridging the adjustable support means located on each side of the
carrier rail and cooperating with the carrier rail to change the position of the carrier
rail upon adjustment of the adjustable support means.
5. A storage system according to claim 4 wherein the carrier rail is a hollow box
section and the bridging members pass through appertures formed on opposite walls
of the box section.
6. A storage system according to claim 4 or claim 5 wherein each guide rail includes
at least one laterally extending flange for supporting a floor which is maintained
at substantially the same level relative to the guide rail during any adjustment of
the guide rail.
7. A storage system according to any preceding claim wherein each adjustable support
means is a screw jack accessible for adjustment before and after loading the storage
unit.
8. A storage system according to any one of claims 4 to 7 wherein the carrier rail
is substantially coextensive with the guide rail to support and reinforce the guide
rail along the length and width of the guide rail.
9. A storage system according to claim 4 including means for locking each adjustable
support means in any adjusted position.