The present invention relates to an improved dock bumper and method of replacing a worn dock bumper, and in particular, although not exclusively to an improved dock bumper for protecting loading bays from being damaged by reversing vehicles.
Dock bumpers or dock buffers are known. The dock bumper is installed on a loading bay and acts to protect the loading bay from damage when vehicles reverse up to the loading bay to load or unload contents from the vehicles. In the simplest form, it is known to form the dock bumper from a solid piece of resilient material. Here, rectangular, L-shaped, or other shaped blocks of typically composite reinforced rubber are bolted on the walls of the loading bay. Reversing vehicles will typically reverse up to and abut the dock bumper. The resilient nature of the rubber block allows the dock bumper to absorb some of the impact energy and therefore protect the loading bay from damage. Although after a number of impacts, the dock bumper becomes worn or damaged, the dock bumper can be simply replaced, saving having to make more serious and costly repairs to the loading bay. The dock bumpers can be produced in a variety of sizes, particularly height, to suit the application, and loading bay engineers are used to specifying the particulars.
More recently, the increased use of airbrakes on heavy goods vehicles has led to an increased wear/damage rate to the dock bumpers. This is because, during loading and unloading and as the airbrakes are turned on and off, the vehicles are caused to rise and lower. When the vehicles are pressed up against the dock bumper, the raising and lowering causes a frictional wear as the vehicle rubs against the dock bumper. Typically, the damage is increased because of the high frictional nature of resilient materials such as rubber. That is, the high frictional coefficient of the rubber causes the rubber to grip the vehicle as it attempts to move causing a tearing or ripping of the dock bumper at the point of impact. It is known to face the dock bumper with polyethylene to reduce the coefficient of friction between the vehicle and bumper in an attempt to allow the vehicle to slide against the dock bumper more readily. However, this is not always achievable because of the large forces involved. Furthermore, because particular loading bays are often accessed by similar vehicles, the dock bumpers are often impacted in a similar position. This repetitive impact can cause uneven wear and often, although the dock bumper is only damaged or worn in one part, the whole bumper requires replacement. Also, the repetitive impact can cause impressions in the surface of the dock bumper which will act to prevent the vehicle from sliding relative to the dock bumper.
More drastically, the up and down movement of the vehicle can be severe enough to rip the dock bumper from the wall of the loading bay. Particularly in cases where there is any prevention of movement between the vehicle and dock bumper. To improve the dock bumper's resistance to damage, it has been known to mount the dock bumper on a sliding frame. For instance, the rubber block is mounted on a nylon plate which slides within a frame. However, this does not prevent uneven wear and the whole dock bumper still requires replacement even though only a small portion of the barrier requires replacement. Furthermore, although the dock bumper may be able to slide upwards from a rest position upon first impact and release of the airbrakes, such dock bumpers are not able to cope as well with downwards initial movement, and the problems associated with a static dock bumper are therefore still present.
It is an object of the present invention to attempt to overcome at least one of the above or other disadvantages. It is a further aim to provide a dock bumper that moves freely relative to the loading bay wall to which it is installed in at least two opposed directions. It is a further aim to provide an improved dock bumper that provides an improved replacement method so that portions of the dock bumper that have not been damaged can be reused. It is a yet further aim to provide a dock bumper that provides a visual impact to act as guidance for reversing vehicle operators. A further aim is to provide a dock bumper that can be manufactured easily in a number of sizes without necessarily having to use bespoke moulds or parts for each size. Yet a further aim is to provide a dock bumper that can be efficiently assembled and disassembled.
According to the present invention there is provided a dock bumper as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.
In the exemplary embodiments, a dock bumper comprises a housing for connection to a dock wall and a plurality of impact elements for absorbing the impact of the reversing vehicle. The impact elements are fixed to the housing and arranged in an array. The housing is for connection to a wall of the loading bay and is adapted to enable the impact elements to roll within the housing. Each impact element comprises an impact absorbing member and an outer layer at least partly enveloping the impact absorbing member, such as an outer sheath arranged about the impact absorbing member. The outer layer or sheath is relatively rigid compared to the impact absorbing member. Consequently, when the vehicle raises or lowers relative to the loading bay wall, the impact elements roll with the vehicle thereby preventing damage caused by relative movement between the vehicle and dock bumper. Furthermore, because the impact elements roll, each specific location of impact has a larger surface area than a flat surface. The life of the dock bumper is therefore typically extended. Furthermore, when the dock bumper becomes damaged and requires replacement, only the damaged impact elements need to be replaced. The remaining impact elements do not need to be replaced and therefore costs and environmental impact may be reduced.
In the exemplary embodiments, the impact elements are arranged in a planar array. That is, the array of impact elements is arranged in a single column or single row with a plurality of rows or columns, respectively. This allows the dock roller to occupy a larger area on a loading bay wall so that the impact of the vehicle can be potentially spread out across a greater surface area.
In the exemplary embodiments, the plurality of impact elements are held within the housing by a plurality of fixing members. The fixing members may be fixed directly between each impact element and the housing. However, the fixing members may be indirectly fixed between each impact element and the housing such that the fixing members are used to contain the impact elements. Furthermore, each fixing member may further couple the dock bumper to the wall of the loading bay or separate fixing members may be provided to connect the housing to the wall.
In the exemplary embodiments, the outer sheath may be designed to move towards the wall by compression or deformation of the internal impact absorbing member. This allows the compression forces to be absorbed by the dock bumper rather than directly through the wall.
In one exemplary embodiment, the reaction force on impact may be absorbed by the fixing members when the fixing members are used as axles to the impact elements. That is, the outer sheath moves towards the fixing member by compression or deformation of the impact absorbing member.
In another exemplary embodiment, the impact elements are freely held within the housing. When the impact elements are freely held the impact elements are allowed to roll. the energy of an impact in this instance is absorbed by one part of the outer sheath moving towards another part of the sheath wherein the movement is controlled by the impact absorbing member such as by compressing or deforming.
In the exemplary embodiments, each impact element includes an impact absorbing member that is arranged to absorb the impact. The impact absorbing member is suitably shown as a resilient member such as a rubber or composite rubber member. The impact absorbing member absorbs the impact of any collision by deforming or compressing to allow an outer surface of the impact element that faces the impact to move relative to the loading bay wall.
Although the impact absorbing member may be sufficient on its own, the exemplary embodiments are provided where each impact element includes an outer sheath to provide the outer surface of the dock bumper. The outer sheath is selected to have a different material characteristic than the impact absorbing member. That is, the outer sheath is selected in some embodiments to have a lower coefficient of friction than the impact absorbing member, particularly where the impact absorbing member, which is selected for its resilient properties, has a high coefficient of friction. This reduces the possibility of friction between the vehicle and dock bumper from generating destructive forces. Additionally or alternatively, the outer sheath may be selected to have a higher rigidity that the impact absorbing member. Here, the outer sheath provides resistance to deformation which could otherwise act to prevent rolling of the impact element. For instance, if the surface impacted by the collision squashed to form a substantially flattened area, the impact element would be less likely to roll as the vehicle moved. However, in some exemplary embodiments, a degree of resiliency in the outer sheath may be beneficial to aid the energy absorption. Furthermore, the outer sheath may be selected to provide an aesthetic surface finish, for instance a particular colour, to provide a visual aid to the reversing vehicle.
In some exemplary embodiments, each impact element is a roller and the dock bumper therefore comprises a plurality of rollers. Each roller is sized suitably in diameter and width to suit the demands of the application. Typically, the rollers are elongate and have a width of approximately 300% greater than diameter. However, the width may be at least 200% or at least 250% greater than the diameter or the width may be greater than 350% or 400% greater than the diameter. In these exemplary embodiments, each roller is shown as being a common size, however, rollers of different sizes are envisaged, wherein the rotational axis of the rollers are set back so the diameters of each roller lie on a common plane.
In one exemplary embodiment, the impact absorbing member absorbs the impact of any collision by allowing an outer surface of the roller that faces the impact to move relative to the rotational fixing between the roller and loading bay wall. Typically, the impact absorbing member is formed along the length of the rollers rather than being concentrated around the rotational fixing. Here, suitably the impact absorbing member is a cylindrical shape.
In one exemplary embodiment, the outer surface of each roller is arranged to rotate relative to the wall of the loading bay. That is, if the dock bumper is repeatedly impacted at one height, the surface of the dock bumper absorbing the impact and therefore prone to damage has been rotated so that a second impact at the same height, impacts a different area of the surface of the dock bumper. The life of the dock bumper is therefore typically extended. Where the roller is formed of two or more materials, the outer material may rotate relative to the inner material. However, it is preferable if the rollers are formed to act as one piece. That is, in the exemplary embodiments, the layers of each roller are fixed fast to each other so as to rotate with one another. In the exemplary embodiments, an axle component is provided which rotates relative to the frame. For instance, it is envisaged that the axle component may be mounted at either end to the frame so as to be able to rotate about its axis. In the exemplary embodiments the rollers are arranged so as to maintain a substantially straight rotational axis even during impact. Whist the material selection may be sufficient to allow the impact absorbing member to comprise the axle component, in the exemplary embodiments, each roller is shown as having a central axle comprising the axle component. The central axle is selected and sized so as to be substantially stiff. For instance, the central axle is shown in some of the exemplary embodiments as being a metal rod such as a steel rod. The rotational axis of each of the plurality of rollers may be spaced in a direction perpendicular to the rotational axis. Here, in one exemplary embodiment, the impact absorbing member is fixed fast to the central axle, for instance through frictional adhesion or other fixing method. The central axle being attached to the frame at each end in a rotational manner. Alternatively, the impact absorbing member may be arranged to rotate about the central axle, which is attached fast to the frame. Here, an axle sheath may be provided to rotate about the fixed central axle, where the axle sheath is secured fast to the impact absorbing member. In the exemplary embodiments, the outer sheath is formed about the impact absorbing member and forms the outer surface of the roller that contacts the vehicle. During impact, the outer sheath moves radially relative to the central axle by compression of the impact absorbing member. That is, the outer sheath moves towards the central axle. As the vehicle lifts or lowers, the roller is caused to rotate, thereby moving with the vehicle and preventing the vehicle from scrubbing against the dock bumper.
In the exemplary embodiments, each impact element, for instance the rollers may be fixed directly to the wall of the loading bay. However, it is preferable to supply the dock bumper as a ready to install device. Consequently, in the exemplary embodiments, a frame is provided. Suitably the frame is substantially U-shaped in cross section so as to provide two opposed side walls that extend away from a mounting plate and between which the rollers may be installed. The frame is adapted to be fixed to the wall of the loading bay in any known and suitable manner, for instance by bolting the mounting plate to the wall.
In one exemplary embodiment, the frame includes rotational fixing points for attaching each roller to. The rotational fixing points may be arranged so that the rollers are spaced approximately 110% of the diameter of the rollers. However, the rollers may be spaced more than 115% or more than 120% of the diameter of the rollers or the rotational fixing points may be spaced at more than 100% or more than 105% of the diameter of the rollers. The rollers are not arranged to touch as they would counter rotate, however, the rollers may be geared together so that rotation of one rotates the others. In the exemplary embodiments however, it is preferable for each roller to rotate independent to the other rollers.
In one exemplary embodiment, each roller rotates relative to the frame. In the exemplary embodiments including the central axle, the central axle protrudes through apertures in the frame. Here, the central axle may rotate within the apertures. In some exemplary embodiments, the rotation between the central axle and frame may be enhanced by the provision of a low coefficient insert such as a nylon insert. Although bearings are possible, they are not thought necessary in all but the highest impact force applications. In other exemplary embodiments, the central axle is fixed fast to the frame and the rollers rotate about the central axle. Again, although bearings are possible, for instance a nylon sheath or sheath of other low-coefficient of friction material, they are not thought necessary in all but the highest impact force applications.
In a first embodiment, each roller comprises an impact absorbing member and an outer sheath, wherein the outer sheath has a different material characteristic to the impact absorbing member and the outer sheath is designed to move towards a rotational axis of the roller by compression of the impact absorbing member.
In the first embodiment, the outer sheath may be arranged to have a lower coefficient of friction than the impact absorbing member. The outer sheath may be arranged to have a higher resistance to deformation than the impact absorbing member.
In the first embodiment, the dock bumper may include a frame wherein each roller may be assembled to the frame in a rotational manner. Each roller may include an axle component that is assembled to the frame, wherein the axle component is arranged to allow the respective roller to rotate. The axle component may be selected to be stiff enough so as not to bend upon impact. The axle component may include a central axle, wherein the central axle is supported by the frame in a rotational manner and the respective roller is attached fast to the central axle. The axle component may include a central axle that is secured fast to the frame, and the respective roller is arranged to rotate about the central axle. The axle component may include an axle sheath, wherein the axle sheath is arranged to rotate about the central axle and the respective roller is secured fast to the axle sheath.
According to the exemplary embodiments, a method of protecting a loading bay from damage may be provided, the method comprising securing a dock bumper of the exemplary embodiments to a wall of a loading bay to be protected, causing a vehicle to abut an impact element of the dock bumper, wherein said abutment causes an outer surface of said impact element to move towards said wall to absorb a portion of the force generated by the impact. The method may further comprise replacing at least one of the impact elements after said impact element has become damaged.
According to a further exemplary embodiment, a method of assembling a first and second dock bumper is provided, wherein each dock bumper is in accordance with the exemplary embodiments. The first dock bumper may have a first height and the second dock bumper may have a second, different height. The method may comprise using a first frame to secure a plurality of first type of impact elements to assemble the first dock bumper and using a second frame to secure a plurality of first type of impact elements to assemble the second dock bumper.
In a second exemplary embodiment, each impact element is provided as a roller and the dock bumper therefore comprises a plurality of rollers. Each roller is sized suitably in diameter and width to suit the demands of the application. Typically, the rollers are elongate and have a width of approximately 300% greater than diameter. However, the width may be at least 200% or at least 250% greater than the diameter or the width may be greater than 350% or 400% greater than the diameter. In the second aspect, each roller is shown as being a common size, however, rollers of different sizes are envisaged. An axle may or may not be provided. When an axle is not provided, the impact members may be freely held so that depression of the impact barrier may also occur as well as rolling of the impact barrier. The rollers may be rotatably fixed. For instance, an axle may be provided, as in the first aspect. When an axle is provided, a rotational axis of the rollers is defined by the axle. The rotational axis of the rollers may be set back so the diameters of each roller lie on a common plane. The rotational axis of the plurality of rollers may be spaced in a direction perpendicular to the rotational axis. The axle may be fixed within the housing or outside of the housing. Alternatively, a combination of fixtures within and outside the housing may be used.
In a third exemplary embodiment, the impact elements may be balls. This advantageously provides a higher density of impact elements per unit area. This helps to better distribute the impact from multiple surfaces of the vehicle. This also helps reduce the wear on each ball because the impact force can be more evenly distributed across the dock bumper. Advantageously, the maintenance requirement of the dock bumper may be reduced. The balls may be provided to be freely held so that the roll direction of each ball is independent and the roll direction can match the movement from the point of impact. Each ball may be sized differently depending on its location on the dock bumper. For instance, the balls on the outside may be softer than the inside or the balls on the inside may be softer than the outside. The size difference between the balls may also vary to provide a varying degree of cushioning and contact heights.
In the second and third exemplary embodiments, the outer sheath may be arranged to also move away from the wall by compression of the impact absorbing member. This movement is in addition to the compression of the impact absorbing members towards the wall during impact. This allows the compression force to be more greatly spread across the impact element which helps to improve the cushioning of the impact and avoid damage to the vehicle and the dock bumper. When the impact elements are freely held, the movement away from the wall may vary depending on the direction of impact. For instance, if the vehicle impacts in a downwardly inclined direction, the compression through the back of the housing may also occur in a downward location. However, on a lateral or side impact, the compression may occur in a different location. This is advantageous over a rotatably fixed impact element because the compression forces can be distributed through different parts of the dock bumper depending on the direction of impact. This helps to increase the life of the dock bumper.
In the second and third exemplary embodiments, the housing may be comprised of an outer housing and an inner housing. The housing may be arranged in a coupled position such that the outer and inner housings are coupled together by the plurality of fixing members. These fixing members may further be used for connection of the dock bumper to the wall. An outer housing is advantageous because multiple impact elements can be removed simultaneously. This helps to reduce downtime because the time taken to service the dock bumper and replace all impact elements is reduced. By coupling the housing together, the coupling force across the impact elements may be more evenly distributed. This allows the height of the impact elements to be consistent and controlled. The fixing members may be concealed by the outer housing. For instance, when inner housing which is for connection to the wall may include separate fixings so that the additional function of coupling the outer and inner housings is separated. For instance, clips may be used to attach the outer housing to the inner housing. These clips may be integral to the inner or outer housings or may be provided separately.
In the second and third exemplary embodiments, the housing may comprise a plurality of pockets when arranged in the coupled position. Each pocket may be capable of at least partially containing each impact element. Furthermore, each pocket is formed from an opening arranged in the outer housing and a recess arranged in the inner housing, wherein in the coupled position, each impact element is partially raised through each opening and each recess accommodates each impact element when each impact element deforms on impact. Furthermore, the shape of each recess corresponds to the external shape of the impact element contained therein. This advantageously helps to improve the distribution of forces on impact because the compression of the impact element is spread over a greater area. Each pocket may be provided with a biasing member to reset the impact element to a desired position after impact. For instance, a spring may be installed in the housing, preferably the inner housing.
In the exemplary embodiments, multiple dock bumpers may be stacked upon or next to each other to change the size of the dock bumper. Advantageously, in the exemplary embodiments including a frame, it is only the frame that needs to be enlarged to provide dock bumpers of different height. That is, the impact elements are a common product between all heights of the same width dock bumper.
In the exemplary embodiments, the dock bumper may be arranged in a multidimensional array whereby there are a plurality of rows and columns. Preferably, the entire multidimensional array contains impact elements. However, the multidimensional array may have vacant cells within the array so that the multidimensional array is not square or rectangular.
For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:
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The impact absorbing member is fixed fast to the central axle by any suitable method but again, a particularly suitable method has been found to be a compression fit formed by making the axle sheath oversized as compared to a bore in the impact absorbing member within which the axle sheath fits. Because the roller acts a single piece, as the vehicle raises or lowers relative to the loading bay, the rollers are caused to rotate and prevent unnecessary damage or forces from being transferred.
The dock bumpers can be increased in size simply by enlarging the height of the frame 20. Consequently, as can be seen in
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From the foregoing it will be appreciated that there is provided an improved dock bumper that is able to accommodate upwards or downwards movement of a vehicle at any point in the cycle of the movement of the dock bumper. Moreover, the environmental impact of the dock barrier is reduced because only damaged parts of the dock bumper need be replaced. Furthermore, the dock bumper may be made more cost effectively as only the frame 20 needs to be changed to produce different height dock bumpers.
Although preferred embodiment(s) of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made without departing from the scope of the invention as defined in the claims.
Number | Date | Country | Kind |
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1307516.3 | Apr 2013 | GB | national |