P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Invention Title: A lifting unit for a loading dock The following statement is a full description of this invention, including the best method of performing it known to us: Field of the invention [0001] The present invention relates to a lifting unit for a loading dock. The lifting unit may be of the type designed to raise/lower palletised goods. The capacity may be 4-8 tonnes. Typically, the application for the invention is to load 5 or offload goods onto/off a truck at a loading dock which is typically at a different level to the support surface on which the truck is situated. Typical applications include factories or supermarket loading docks for loading/offloading of goods. Background to the invention [0002] Typically, loading dock hoists are of the size and capacity that they are 10 able to accommodate goods loaded onto pallets, typically from 2 to 8 pallets. Known loading dock hoists generally incorporate a scissor mechanism to raise/lower a movable platform. The movable platform typically moves between a lower support surface e.g. where the truck drives up, and an upper support surface such as a loading dock. Since the movable platform needs to move to a 15 position where it is level or at least substantially level with the lower support surface, the scissor mechanism is accommodated in a pit. The problems with a pit include the installation costs and the problem of filling up with water and rubbish. [0003] It is therefore an object of the present invention to provide a lifting unit 20 for a loading dock which overcomes the above mentioned problems, or at least provides the public with a useful choice over known lifting units. [0004] Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or 25 that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art. Summary of the invention [0005] In accordance with a first aspect of the present invention, there is provided a lifting unit for a loading dock, the lifting unit including: a movable 30 platform movable relative to a fixed support from a lowered position to a raised position, the movable platform having a platform base defining a platform floor, 1A wherein the lifting unit, including the movable platform and the fixed support is mountable on a substantially level support surface whereby the combined thickness of the platform base in the lowered position and any portion of the fixed support lying beneath the platform base, is of low profile. 5 [0006] By "low profile", is meant a height whereby it is: practical for a single person to push a palletised load on a pallet truck onto the platform floor without the use of a ramp; or possible to move a palletised load on a fork lift truck onto the platform floor without the load becoming unstable, without the use of a ramp. In other words, the combined thickness is relatively thin. Thus, the short height of 10 the platform floor above the substantially level support surface enables pallets to be easily moved from one to the other While the definition of "low profile" enables effective transfer without the use of a ramp, advantageously, a short ramp may be carried by the movable platform for even easier transfer. [0007] Preferably, the height of the platform floor above the substantially level 15 support surface is in the range of approximately 50mm to approximately 100mm. The preferred height of the platform floor above the substantially level support surface is about 80 to 85mm. [0008] By "level" is meant having no part higher than another or having an even surface. Thus by "substantially level" we mean that strict compliance with 20 this meaning is not required; and substantially level means that no part is appreciably higher than another in respect of the support surface. [0009] The low profile platform base mountable on a substantially level support surface, being the same surface which also supports the vehicle, is achieved by the interrelated design of the platform base and the fixed support beneath the 25 platform base. Preferred features of this interrelationship are set out further below in connection with the third aspect of the invention. Thus, features set out in any of the other aspects of the invention may be incorporated into the first aspect of the invention. Additionally, the low profile platform base is preferably achieved by having one or more moving devices for moving the platform 30 disposed wholly to a side of the platform base, minimising bulk underneath the platform base. [0010] In accordance with a second aspect of the present invention, there is provided a lifting unit for a loading dock, the lifting unit including: a movable platform movable relative to a fixed support from a lowered position to a raised 2 position, the movable platform having a platform base defining a platform floor, wherein the lifting unit, including a movable platform and the fixed support is mountable on a substantially level support surface, and wherein the movable platform is movable via one or more moving devices disposed wholly to a side of 5 the platform base. [0011] If the platform is elongate, then the moving device(s) may lie at the side(s) or at the end(s) of the platform but not underneath. Preferably there are two moving devices operating on opposite sides of the movable platform. [0012] Preferably, the movable platform has opposite platform sides and the 10 moving devices operate to raise/lower a respective one of the platform sides. The moving devices are preferably interconnected such that they raise/lower the opposite sides at the same rate to maintain the opposite platform sides at the substantially same level. [0013] Preferably, the moving devices comprise hydraulic/pneumatic cylinders. 15 Preferably, the cylinders are fluidly interconnected. Two hydraulic cylinders may be phasing cylinders to maintain level operation of the platform. In an alternative arrangement of interconnecting the two cylinders, each cylinder may have a dedicated pump in a master/slave arrangement with position encoders on both sides and a control system receiving signals from the position encoders to control 20 the pumps to maintain the position encoders and hence both sides of the platform at the same height. [0014] Guide means may also be provided to avoid tipping or seesawing of the platform. For this purpose, the platform sides are preferably guided by the fixed support during raising or lowering. This may be achieved by one or more rollers 25 provided on the platform sides engaging with one or more tracks provided on the fixed support. [0015] Any of the features described in accordance with the other aspects of the invention may be incorporated into the second aspect of the invention. [0016] In accordance with a third aspect of the present invention, there is 30 provided a lifting unit for a loading dock, the lifting unit including: a movable platform movable relative to a fixed support from a lowered position to a raised position, the movable platform having a platform base defining a platform floor, wherein the lifting unit, including the movable platform and the fixed support, is mountable on a substantially level support surface and the movable platform is 3 movable via moving devices, wherein the fixed support underneath the platform base has a profile projecting from the substantially level support surface, said profile being at least partially accommodated by the profile of the underside of the platform base. 5 [0017] Therefore, in a preferred form of the invention, the portion of the fixed support underneath the platform base and the underside of the platform base have substantially complementary profiles. Described another way, the fixed support underneath the platform base and the underside of the platform base may be nested. For example, the platform base may include a plurality of 10 platform cross-members which are spaced apart and extend substantially from one side to the other. The fixed support may include fixed cross-members which are spaced apart and extend substantially from one side to the other. One or more of the fixed cross-members may be disposed between adjacent platform cross-members. Preferably, the platform cross-members and the fixed cross 15 members alternate. Sufficient space between the platform cross-members and the fixed cross-members may also provide for pipes and cabling extending from one side of the platform to the other. [0018] Any of the features described in connection with the other aspects of the invention may be applied to the third aspect of the invention. 20 [0019] In accordance with a fourth aspect of the present invention, there is provided a lifting unit for a loading dock, the lifting unit including: a movable platform movable relative to a fixed support from a lowered position to a raised position, the movable platform having a platform base defining a platform floor, wherein the lifting unit, including the movable platform and the fixed support, is 25 mountable on a substantially level support surface and wherein the movable platform further includes a loading lip which is movable from an inoperative position to an operative position such that when the platform base is in the lowered position, the loading lip forms a functional loading ramp between the platform floor and the substantially level support surface. 30 [0020] In the preferred form of the invention, the platform base has a low profile and thus the loading lip need only provide a short ramp to extend from the platform floor to the substantially level support surface. A loading lip may be provided on one or both ends of the movable platform. 4 [0021] Preferably, each loading lip is movable from a substantially upright position where it functions as a barrier at the end of the movable platform, to the operative position. Preferably, each loading lip is mechanically movable. [0022] Any of the features described in connection with the other aspects of 5 the invention may be applied to the fourth aspect of the invention. [0023] In accordance with a fifth aspect of the present invention, there is provided a lifting assembly for a loading dock, the lifting assembly including: a lifting unit including a movable platform movable relative to a fixed support from a lowered position to a raised position, the movable platform having a platform 10 base defining a platform floor, wherein the lifting unit, including the movable platform and the fixed support is mountable on a substantially level support surface; and at least one vehicle stop mounted on the substantially level support surface or the fixed support at a forward end of the lifting assembly, wherein the stop is supported by a brace extending rearwardly to a lower end of the brace 15 which is secured to the substantially level support surface or the fixed support. [0024] The vehicle stop effectively enables the vehicle to "touch park" and come to a stop once the vehicle makes contact with the stop. Since the stop is braced, the stop is able to withstand a heavy impact from the vehicle. The rearward bracing is possible in this floor mounted lifting assembly, something 20 which could not be achieved in the prior art form of the loading dock hoist because of the presence of the pit. [0025] The vehicle stop may include detection means providing a warning signal to the driver of the vehicle. The warning signal may take the form of an audible or visual signal such as a traffic light, warning light, audible alarm and the 25 like. A counter may also be incorporated to obtain statistics about the use of the loading dock. [0026] In a preferred form of the invention, the brace incorporates resilient means to absorb energy from vehicle impact. For example, the resilient means may comprise resilient material or alternatively a spring. The construction of the 30 brace may facilitate retraction on impact. [0027] In a preferred form of the invention, the movable platform has side walls and the fixed structure also has outer side walls, with each outer side wall being outwardly of a respective platform side wall. Preferably there are two stops, each disposed forwardly of a platform side wall and the adjacent outer side wall on a 5 respective side of the lift assembly. Preferably, the brace extends rearwardly between the associated platform side wall and the outer wall. [0028] Any of the features described above in connection with any of the other aspects of the present invention may be incorporated into the fifth aspect of the 5 present invention. Brief summary of the figures [0029] In order that the invention may be more fully understood, one embodiment will now be described by way of example, with reference to the figures in which: 10 [0030] Figure 1 is an illustration of a preferred embodiment of the present invention used to load/unload between a vehicle and a loading dock; [0031] Figure 2 is an illustration of the lifting unit according to Figure 1 used to load/unload between a vehicle and the support surface on which the vehicle is supported; 15 [0032] Figure 3 is an illustration of the lifting unit according to Figure 1 used to load/unload between a vehicle and the support surface on the other end of the lifting unit; [0033] Figure 4 is an illustration of the lifting unit according to Figure 1 used to load/unload from a support surface supporting the lifting unit to a raised loading 20 dock; [0034] Figure 5 is a perspective view of the lifting unit illustrated in Figure 1; [0035] Figure 6A is a perspective view showing the detail of A in Figure 5; [0036] Figure 6B is a perspective view showing the detail of B of Figure 5; [0037] Figure 7 is a side view of the lifting unit shown in Figure 5 with a vehicle 25 reading for loading/unloading; [0038] Figure 8A is a detailed side view of A in Figure 7; [0039] Figure 8B is an alternative detailed side view of A in Figure 7; [0040] Figure 8C is another alternative detailed side view of A in Figure 7; [0041] Figure 8D is another alternative detailed side view of A in Figure 7; 30 [0042] Figure 8E is another alternative detailed side view of A in Figure 7; [0043] Figure 9 is a schematic view of the phasing cylinders used in the lifting unit of Figure 5; 6 [0044] Figure 10 is a side view, similar to Figure 7 except with the outer wall removed, showing one of the vehicle stops. Detailed description of the figures [0045] The application of the lifting unit 10 is best understood by reference to 5 Figures 1 to 4 which show various different scenarios in which the lifting unit 10 may be employed. [0046] In Figure 1A, the lifting unit 10 is mounted on a substantially level support surface 12. The lifting unit 10 may be bolted or otherwise secured to the substantially level support surface 12. This support surface is the same as that 10 used to support the vehicle 14, depicted schematically in Figure 1A. The vehicle 14 is a able to drive over the substantially level support surface 12 and reverse up to the lifting unit 10 until the end of the vehicle 14 is substantially aligned with the lifting unit 10. The lifting unit 10 is installed adjacent a loading dock 16. The loading dock 16 is raised above the level of the substantially level support 15 surface 12. The loading dock 16 may be level with the floor of the building into which the goods are delivered or from which they are shipped. For example, the loading dock 16 may be the loading dock of a supermarket where goods are delivered. [0047] When the vehicle has reached its optimum position aligned with the 20 lifting unit 10, the movable platform 18 of the lifting unit 10 is raised to the same or similar height as the floor of the vehicle 14. At this point, the hydraulically operated loading lip 20 is moved to its operative position onto the vehicle floor to bridge the gap between the vehicle floor and the platform floor 22. At this point, goods may be unloaded from the vehicle 14. These goods are usually stacked 25 onto pallets and the pallets are moved onto the platform floor 22 using appropriate pallet moving equipment e.g. single pallet manual mover such as a pallet truck. The lifting unit 10 is designed to comfortably accommodate a whole number of pallets. The number of pallets able to be accommodated may range between to 2 to 8. 30 [0048] Once the desired number of pallets have been moved onto the lifting unit 10, the loading lip 20 is raised to a substantially upright position as illustrated in Figure 1 B. The loading lip 20 prevents personnel or goods from falling from the movable platform 18. The movable platform 18 is raised until the floor 22 of the 7 platform is level with the loading dock 16. The pallets may then be unloaded onto the loading dock 16. [0049] Figure 2 illustrates an alternative scenario where goods are unloaded from the vehicle 14 and transferred via the lifting unit 10 onto the substantially 5 level support surface 12. In doing so, the platform 18 is raised to be level with the vehicle floor, upon which the loading lip 20 is moved to its operative position to bridge the gap therebetween so that goods may be moved from the vehicle floor to the movable platform 18. The loading lip 20 is then raised to a substantially upright position and the platform 18 is lowered until the platform floor 20 is 10 substantially level with the support surface 12. The construction of the platform base, to be discussed further in connection with Figure 8, is such that the platform floor 20 is approximately 80-85mm above the support surface 12. At this point, the loading lip 20 is lowered to its operative position and palletised goods may be rolled from the platform to the support surface 12. 15 [0050] Figure 3 illustrates an alternative application of the lifting unit 10 in transferring goods from the vehicle 14 parked at one end of the lifting unit 10 to the substantially level support surface 12 at the other end of the lifting unit 10. The platform 18 is raised to the level of the vehicle 14 at which point the palletised goods may be unloaded onto the platform 18. The loading lip 20 is then raised and the platform 18 is lowered to its 20 lowered position whereby the platform floor 22 is substantially level with the support surface 12. To aid the pallet truck in being able to roll from the platform floor 22 to the support surface 12, a floor ramp 24 is provided at the other end of the lifting unit 10. The floor ramp 24 may be a permanent fixture on the support surface 12. Alternatively, the lifting unit 10 may have a loading lip 20 at the other end. 25 [0051] Figure 4 illustrates an alternative application where a vehicle is not involved but it is simply desired to move goods from one level to another e.g. from the support surface 12 to the loading dock 16. [0052] The features of the lifting unit 10 will be described in greater detail in connection with figures 5-8. The lifting unit 10 includes a fixed support 30. In figure 5, the 30 fixed support includes outer walls 32 extending upright from support surface 12. The outer walls 32 may include framing components 34 and appropriate external cladding 36. Some of the cladding 36 has been removed in figure 5 for the sake of clarity. The fixed support 30 further includes fixed cross members 38 (see figure 8) mounted on fixed base plates 40. The fixed cross members and fixed base plates 40 are secured to the 35 substantially level support surface 12. The substantially level support surface 12 may be 8 a concrete slab 13 and the elements of the fixed support are suitably bolted or otherwise secured to the concrete slab 13. [0053] The fixed support 30 also include a guide mast 42 which includes guide rails 44, 46 such as those depicted in figure 6, used to guide the platform 18 in its traverse 5 between the lowered and raised positions. This will be explained further in conjunction with figure 6 below. [0054] The platform 18 includes a platform base which defines the platform floor 22. [0055] The platform base is depicted in greater detail in figure 8A. The platform base includes platform cross members 50 and the platform floor 22 in the form of a folded 10 metal tray, e.g. steel. The cross members 50 may be welded to the platform floor 22. The platform cross members 50 in the form of a folded reinforcing trays 51 extend from side to side across the platform 18 and are spaced apart so as to define channels 52 therebetween. These channels 52 are able to accommodate the fixed cross members 38. More specifically, there are a series spaced platform cross members 50 which define 15 a profile on the underside of the platform base. These recesses 52 in the profile accommodate a respective one of the fixed cross members 38. Thus, the profile of the underside of the platform base is somewhat or substantially complementary to, and able to accommodate the profile of the fixed support underneath the platform base. The recesses 52 may provide additional space to accommodate hydraulic pipework and 20 electrical cables 54 traversing from one side of the platform to the other. In particular, the phasing cylinders 70, 72 discussed in connection with figure 9 are fluidly connected from one side of the platform 18 to the other. [0056] Figures 8B to 8E show alternative constructions of the platform base. In each of these examples, the profile of the underside of the platform base is somewhat or 25 substantially complementary to, and able to accommodate the profile of the fixed support underneath the platform base. In Figure 8B, on the underside of the base, platform cross members are in the form of folded reinforcing trays 51' folded about the platform cross struts 50' to define a gap which tapers in width away from each fixed cross member 38. In Figure 8C, two or more proprietary rectangular hollow sections 50" are used as the 30 platform cross members. In Figure 8D, a corrugated profile 50'" is used as the platform cross member. In Figure 8E, a series of individual stiffeners 50"" are used as the platform cross member.The platform 18 also includes platform sides 60. These platform sides are typically in the form of upright walls on opposite sides of the platform 18 and joined to the platform base. Each upright wall has appropriate framing such as depicted 35 at 62. On the inside, the sidewalls 60 are covered with cladding 64, although some of the cladding 64 has been removed from figure 5 for the sake of clarity. [0057] The platform 18 is caused to be raised and lowered relative to the fixed frame 30 by means of two hydraulic cylinders arranged on opposite sides of the platform 18. 9 [0058] The hydraulic cylinders 70, 72 cannot be clearly seen in figure 5. Reference is made to figure 9 which is a schematic illustration of the operation of the hydraulic cylinders 70, 72. [0059] The hydraulic cylinders 70, 72 shown schematically in figure 9 are supported 5 on the fixed support 30 or the support surface 12. The hydraulic cylinders 70, 72 have piston rods 74, 76 projecting from the ends of the cylinders. The rods 74, 76 connect to respective platform sides 60 to raise and lower the platform 18. It is therefore desirable that the cylinders 70, 72 operate so that the piston rods 70, 76 are evenly extended to avoid tipping or seesawing of the platform. This is particularly desirable when the pallet 10 loads are unevenly balanced on the platform 18. The even operation of the cylinders 70, 72 is achieved because the cylinders 70, 72 operate as phasing cylinders, in a manner which will be appreciated by those skilled in the field of hydraulics. [0060] The master cylinder 70 has a piston 78. Hydraulic fluid lies in the volume above the piston 78, surrounding the rod 76. The contact area of a hydraulic fluid on the 15 piston 78 is an annulus area C. The master cylinder 70 is connected to the slave cylinder 72 by fluidly connecting the volume above the piston 78 with the volume below the piston 80 of the slave cylinder 72. The piston 80 has an area D operated on by the hydraulic fluid below the piston 80. The annulus area C equals the piston area D so that both piston rods 76, 74 will displace the same distance regardless of the load on each 20 cylinder. This method is used to keep the platform level, even where the load on the platform is not evenly balanced. [0061] Figure 9 also illustrates the tank 82 providing the supply of hydraulic fluid and motor 84 which drives the pump 86. Operation of the pump controls the fluid to the barrel end of the master cylinder 70 to drive the piston 78 up or down as desired and the slave 25 cylinder 72 follows accordingly by virtue of being interconnected with the master cylinder as already explained. [0062] Error correction may also be employed in the hydraulics to account for typical leakage of hydraulic fluid, which if not corrected, would lead to the cylinders 70, 72 being out of phase. The correct is obtained using limit switches to detect the bottom of stroke. 30 If and when one cylinder reaches the bottom of the stroke before the other, then valves redistribute the hydraulic fluid until the cylinders are synchronised again. [0063] As shown in Figure 6, the path of the platform 18 relative to the fixed support 30 is guided through roller pairs A and B which operate on the guide mast 42. There are four sets of A roller pairs 90 (see Figure 6A). Two sets of A roller pairs operate on one 35 side of the platform 18, while two sets of A roller pairs operate on the other side of the platform 18. As shown in figure 6A, each pair of A rollers are mounted to the platform, with the axis of the rollers aligned with the transverse (side to side) direction of the platform 18. The rollers A roll on opposite side of the upright rail 44 forming part of the 10 guide mast 42. The four sets of A roller pairs hold the platform level and prevent tipping or see-sawing about a transverse axis of the platform 18. [0064] There are also four sets of B roller pairs which hold the platform level and prevent tipping or see-sawing about a longitudinal axis (end to end) of the platform 18. 5 There are two pairs of B rollers on each side of the platform. The B roller pair 92 depicted in Figure 6B is mounted to the platform side 60 with the axis of the rollers aligned with the longitudinal direction of the platform 18. The rollers 92 lie on opposite sides of a guiderail 46, forming part of the guide mast 42. The four sets of B roller pairs, in conjunction with the phasing cylinders prevent tipping or see-sawing about a 10 longitudinal axis of the platform 18. [0065] As shown in Figure 5, the lifting unit 10 also includes two spaced vehicle stops 94. The vehicle stops 94 are disposed at a forward end of the lifting unit 10 and are spaced apart so as to not to impede the flow of goods into the platform 18, nor effect the operation of the loading lip 20. Each vehicle stop 94 generally lies in front of the forward 15 ends of the inner wall 60 and the outer wall 32. [0066] Referring to figure 10, each vehicle stop 94 includes a post 96 provided with a base plate 98 which is bolted to the concrete slab 13. At the upper end of the post 96, the forward side is provided with resilient impact material 100 which serves to buffer the impact to the stop 94 when struck by a vehicle. The post 96 is also braced by a 20 rearwardly extending, inclined brace 102. The brace 102 is attached to the upper end of the post 96 at its upper end and is secured to the concrete slab 13 by being bolted thereto through the base plate 104. The brace 102 includes resilient, impact absorbing material 106, such as a polyurethane block to aid in absorbing the impact of a vehicle striking the stop 94. Various brace designs may be employed to optimise the impact 25 absorption characteristics of the brace 102. For example, the brace may comprise two telescopic parts which shorten on impact. Alternatively, a concertina construction may be employed. [0067] This construction reduces the forces in the masonry anchors and allows the stop 94 to be fixed to a concrete slab 13 that would otherwise be inadequately reinforced 30 or of a substandard grade for conventional bollards. [0068] On each side, the brace 102 extends rearwardly between the inner wall 60 and the outer wall 32. Instead of being attached directly to the concrete slab 13, the stop 94 may be alternatively affixed to the fixed structure 30. [0069] The foregoing describes only one embodiment of the present invention and 35 modifications may be made thereto without departing from the scope of the present invention which is defined in the following claims. 11