SAFETY DEVICES FOR TIPPER UNLOADING TYPE DUMP TRUCKS

The present invention relates to safety devices for tipper unloading type dump truck dump bodies, where a safety device prevents unsafe conditions from occurring when raising the dump body for unloading loose material, that is, with active safety devices; or in addition a different safety device facilitates the unloading of the material in the dump body, that is, with passive safety, on raising the dump body, facilitating the unloading of the transported loose material, such as grain, a dry material that tends to clump.

The prior art, in this specific sector, includes safety or unloading devices for clumped material, where the components of the support frame of the dump body are placed as further support, as well as the telescopic elevation cylinder, for the inclined dump body when it is almost in the completely raised position. Unloading devices, on the other hand, mainly involve the use of vibrators applied to the outside of the dump body to break up the clumps inside the transported material in order to make the material slide down the inclined dump body. For strongly clumped material, in the prior art also mobile scraping devices for the dump body, which are used when the dump body is inclined; or swinging devices attached to the dump body end wall, to push the residual material out of the dump body are known.

Disadvantageously, it has been noted that the transported material that is usually difficult to unload in the area that is furthest from the rear unloading hatch, such as grain, dry or very fine grained material, tends to clump further in relation to the amount of time it is left in the dump body and the vibration caused by transport from the loading location to the unloading location.

In the prior art, in patent application KR 2002 0065679, a semi-trailer frame is well-known which, when the dump body is being unloaded, is positioned in an inclined and normal direction in relation to the dump body itself, in order to form a triangle with the dump body and the telescopic hydraulic elevation cylinder. The safety aspect regards the partial removal of the force from the lifting cylinder, which in the extended position is not loaded with the entire load of the end of the dump body, but only with that which does not

unload towards the frame placed in a normal position with regard to the dump body, thus operating as an isostatic structure.

Therefore, safety during the unloading procedure depends on the possibility for movement of the wheels of the semi-trailer which during lifting must be able to move closer to the engine and, on reaching the highest elevation, be stopped to allow an increase in the load on the frame in the normal position of the dump body.

Also in other embodiments of safety devices, the parts added, in place of the telescopic hydraulic cylinder in the highest elevation position, prevent, control and reduce uncontrolled oscillation of the front end of the dump body, which sometimes occurs when the operator moves the truck with the dump body in the elevated unloading position, therefore, at the highest elevation, to help shift the material remaining in the dump body itself.

This operation, as has been encountered in practice, is very dangerous as the entire procedure depends on the ability of the operator and on the unloading location and often causes the dump body to sway heavily, which is increased and aggravated by the clump of material present in the lifted end of the dump body. In some cases the latter has caused the yielding of the telescopic hydraulic cylinder, the falling of the dump body and, most dangerously, damage to the cab and the injury or death of the operator.

In addition, in the prior art, in patent US 5002340 A, to remove the clumped material from the dump body, such as earthy material in "dumpers", a device for scraping the bed of the dump body is known, which is guided by lateral dragging cables positioned in the corners between the base and the lateral walls of the dump body.

However, to complete the unloading devices there are gravity oscillating blocks in the dump body end wall. The said device, which normally rests against the end wall of the dump body when it is in a horizontal position, pushes the clumped material from the bed only when the dump body is inclined and with force that is proportionate to the inclining of the dump body itself, therefore with a weak pushing action on the clumping material and only in the base position of the clump.

Disadvantageously, the devices described do not allow the complete

unloading of the loose material to be carried out, due to the presence of the frame of the scraper, which does not permit the material to fall completely onto the dump body bed, and due to the effect of gravity of the pushing device located on the end wall, which acts slowly and constantly.

Further prior art, in patent US 6209964 B1 , is known where vibrators connected to the bed of the dump body are placed in strategic points as specified several times in the text, to remove the internal clumps in the loose material, which during transport tends to clump and become difficult to unload as it is further from the unloading hatch of the dump body.

On the other hand, the use of vibrators attached to the dump body has been known for a long time, even before the above-mentioned patent, as the latter is a specific conformation of a vibrator device that is advantageous in the described embodiment. Therefore, with just the application of vibrators, even if it is well-known, to act passively, or rather, without acting directly on the mechanic elements, ensuring the solidity of the dump body elevation components, it is not possible to obtain the complete and easy emptying of the residual loose material in the farthest end of the dump body near the end wall, so the operators turn to agitation induced by moving the dump truck, thus creating dangerous situations for their safety and the safety of people in the surrounding unloading area.

To summarise the disadvantages present in the prior art, also with the use of the said devices, the emptying of a dump truck dump body, even when in the elevated position, is made difficult by the tendency of the transported material to clump and obstruct the emptying of the end of the dump body. In fact, the operator frequently agitates the material in the dump body by intervening with the backwards and forwards movement of the dump truck, causing the residual load to move and making the manoeuvre very dangerous, due to the material in the front part of the dump body being further from the unloading hatch, causing an imbalance of the mass when the dump body is raised.

The said prior art is subject to considerable improvement with regard to

the possibility to design active and passive safety devices for the dump body when in the inclined position, even at the maximum elevation, in order to avoid the yielding of the telescopic hydraulic elevation cylinder, which occurs when the dump body is agftated strongly, due to the dump truck being moved in order to make the loose material fall towards the rear unloading hatch.

A further but no less important aim of the present invention is to design a passive safety device that facilitates the unloading of the loose material and that can be used in combination with the said active safety device or separately. Another but not exhaustive aim of the present invention is to design a passive safety device that can be manoeuvred depending on the different types of loose material carried in the dump body, in order to carry out forcing unloading actions that depend on and/or gradually increase in strength with regard to the different clumping tendencies, often shown by different loose materials or by different loads of the same type of material, loaded at different times into the same dump body.

What is described above demonstrates the need to solve the technical problem of designing: an active safety device that allows the dump body to be kept in the elevated position without making the entire load bear heavily on the telescopic hydraulic elevation cylinder. This device has a simple composition and is easy to manufacture, as well as being able to intervene automatically as the dump body is elevated.

A further technical problem for passive safety, as a corollary to the latter, is to design loose material unloading devices in the front end of the dump body, which are effective and act quickly, or rather without requiring long movements of the device or localised actions distant from the point of action on the clump of loose material.

The present invention solves the said technical problem by adopting a safety device for tipper unloading type dump truck dump bodies, including a dump truck with a rear tipper dump body; a safety device that can be activated with the increase in inclination of the dump body; extendable lifting components for the dump body to raise one end of the dump body from the dump truck frame; wherein the said safety device includes at least one pair of struts, one

end of which is connected by rotation externally and interiorly to the dump bed, on its front part, and with the opposite end sliding on guides connected to the dump truck frame, on its rear part; there are blocking devices for the ends of the struts on the frame or guides when the elevation of the dump body is increased; the length of the said struts being sufficient to keep them at an inclination that is in the same direction as the dump body and to avoid sticking when moving backwards.

In addition, in other embodiments of the invention, the following are present singularly or in combination: struts connected to each other to form a frame; strut stiffening or reinforcement components and/or joints in the frame; the said frame being provided with braces between the struts; guide components at least one of which is in the shape of a "C" and between which the sliding components located at the ends of the struts are housed; the said blocking device includes a ratchet-gear component that engages with a toothed coupling component; the said toothed component associated with the guide or guides at the sliding end of the struts; the said blocking device controlled by an actuator that is activated by remote control; advantageously, the said blocking device is controlled by a pneumatic actuator.

Further still, other embodiments of a safety device for a tipper unloading type dump truck dump body, include a dump truck with rear tipper dump body; a safety device that is activated on inclination of the dump body with mobile components at the end of the dump body that is furthest from the unloading hatch; characterised by fact that in the area of the dump body that is furthest from the rear unloading hatch a device for agitating the transported loose material is present, which is controlled by the operator.

In addition, in further embodiments of the first variation of the invention the following are present separately or in combination: as an agitating component for the transported material at least one inflatable component that is inflated by means of fluid, attached to a wall or the dump bed in the area of the latter that is furthest from the unloading hatch; more than one inflatable component positioned on the walls or bed of the dump body; the said components being activated by the fluid pressure not contemporaneously; the inflatable component or components activated by vibration, that is, with sudden repeated and alternated variation in the fluid pressure.

Further still, in further embodiments of a second variation of the invention the following are present separately or in combination: an agitating component for the transported material which penetrates the material in the area of the dump body that is furthest from the rear unloading hatch and also acting at a height that is lower than half of the height of the dump body edges; the component that penetrates the material is composed of a rack with at least one or more sections immersed in the area of the dump body that is furthest from the unloading hatch; the said rack is made to vibrate by a vibrator applied to it; the said rack rotates around an axis parallel to the dump body bed and is distant from the bed by at least the length parallel to the bed of the said section(s) of the rack; the said rack rotates around an axis parallel to the dump body bed and is positioned on the dump body bed; the said rack rotates around an axis parallel to the dump body bed, distant from the latter at a distance that is established on unloading the material from underneath the said axis and the said section of the rack; applied to the rack at least one vibrator; on the front external part of the dump body bed at least one vibrator applied near the area underneath the rack rotation axis.

One method of implementing the invention is illustrated, purely in the form of examples, in the seven drawings enclosed in which Figure 1 illustrates a schematic view of the side of a tipper unloading type dump truck with the dump body in the transporting position with the active safety device folded away; Figure 2 illustrates the schematic view of the side of the dump truck shown in Figure 1 with the dump body at maximum elevation and the active safety device, in accordance with invention in question, in use; Figure 3 illustrates a schematic view in direction F of Figure 2, of the end part of one of the two struts of the safety device; Figure 4 illustrates a schematic view, in direction P of Figure 2, of the frame with the said struts; Figure 5 illustrates a schematic V-V section of Figure 4; Figure 6 illustrates a schematic view, in direction P of Figure 2, of a further frame embodiment with the said struts; Figure 7 illustrates a longitudinal schematic VII-VII section of Figure 3, of the end part of one of the struts with the automatic blocking mechanism; Figure 8 illustrates a schematic view of the side of a dump truck, as in Figure 1 , also with the application of a passive safety device with inflatable-vibrating cushions, for the unloading of clumped loose material; Figures 9 and 10 illustrate enlarged side and plan

schematic views of the end part of the dump body in Figure 8; Figure 11 illustrates a schematic view of the side of a dump truck, like Figure 1, also with the application of a passive safety rotating rack device by means of actuator cylinders, for the unloading of clumped loose material; Figure 12 illustrates a schematic view of the side of a dump truck, similar to Figure 11 , also with the application of a passive rotating rack safety device by means of rotation actuators; Figures 13 and 14 illustrate enlarged side and plan schematic views of the end of the dump body in Figure 11 ; Figures 15 and 16 illustrate enlarged side and plan schematic views of the end of the dump body in Figure 12.

Figures 1 and 2 show a dump truck 1 with rear tipper dump body 2, where the dump body is inclined with respect to the frame 3 of the dump truck, raised by a customary telescopic actuator cylinder 4, which is located near the cab 5 of the vehicle; a device 6 for active safety with struts 7 is housed between the dump body 2 and the frame 3. The struts are joined to the dump body on an axis 8, which is parallel with and transverse to the bed of the said dump body, positioned at the front part 9 of the dump body bed. The said struts slide in pairs of guides 10, 11 with their end 12 and are provided with stopping components 13 for automatic activation during inclination of the dump body. Figures 3 to 7 show also an actuator cylinder 14 for the release of the stopping components 13, which in this embodiment are shown with an oscillating spout 15 at every contact of the end 16 with the teeth 17 of the rack 18 housed between the two guides 10 and 11; the actuator cylinder 14 is only activated on release to raise the end of the spout 16, disengaging it from the rack tooth. The idle position of the spout 15 is near the side of the strut, making the automatic release movement possible, as the struts 7 gradually increase their inclination; the wheels 19 coupled by rotation to the ends 12 of the struts 7 reduce the resistance to the sliding of the ends 12 in the pairs of guides 10 and 11. The struts 7 are connected to each other by means of at least one cross piece 20, in order to make the struts more resistant to bending at full load. In the joints 21 between the struts and cross pieces, as well as in the ends 12 of the struts there are strut section stiffening reinforcements 22. In Figure 6 the frame 23 between the struts 7 and the cross pieces 20 is then further stiffened with the crossed braces 24.

In Figures 8 to 10, in a first embodiment of a passive safety device, on the dump body 25 of the dump truck 26 some inflatable cushions are positioned on the walls at the end 27, and to the right and left 28 and 29 of the area 30 of the dump body that is furthest from the material unloading hatch 31. An inflatable cushion 32 is also positioned on the bed in the area 30 to act on the clump of loose material in the said area from underneath. For purposes of clarification, the right lateral cushion 28, is shown deflated, while the others are shown fully inflated. The lateral cushions or the one on the bed do not necessarily all have to be present at the same time, as devices may be realised with only one or more than one of the said inflatable cushions. Advantageously, the flexible material used for the said cushions is high-resistance rubber canvas, which is well-known in the prior art.

The material used for the inflation, which is introduced into the cushions by means of an inlet/outlet pipe 33 in the rear wall of each cushion, may be gaseous, such as compressed air or compressed exhaust gas of the dump truck, or also liquid material such as that of the hydraulic liquid of the telescopic cylinder activation system, or other systems that the dump truck may have, or also the liquid resulting from technological or natural processes, such as water, which may be available on the route or at the loading and unloading locations where the dump truck carries out the transportation. Only in the case of valuable liquid, such as hydraulic fluid, must its recovery be provided for when emptying, while the unloading action can easily be obtained with the cushion(s) partially inflated and with the fluid inlet and outlet control, repeated at high frequency; the latter being achieved by means of a feed device with pressure source valves, which are not shown but are well-known in the prior art, in order to generate enough vibration in the loose material in contact with the cushion to break the internal clumps and allow the unloading of the said material from the area 30 of the dump body.

In Figures 11 to 16, in further embodiments of a passive safety device, in the dump body 35 of the dump truck 36 is inserted a rack device 37 which has a rotation axis 38 in a transverse direction to the dump body in the area 39 of the dump body that is furthest from the material unloading hatch 31. The rotation

axis is positioned at a height D from the dump body bed to facilitate the unloading of the loose material from under the said axis. The rack has a section 40 approximately in a parallel direction to the dump body bed and at least one other section 41 approximately in a vertical or sub-vertical direction to the said dump body bed. At least one actuator cylinder 42 is positioned between the dump body and the rack 37 to move the said rack by rotation, even if limited as shown, to make it move the said sections 40 and 41 within the mass of loose material loaded in the said area 39 of the dump body. For the movement of the rotating rack, there is also, in alternative, a rotation actuator 43 for the rack 37, applied directly to its rotation axis 38. To the rack can be applied a vibrator 44 that, if desired, can be placed inside the mass of loose material loaded.

The vibrator 44 is in contact with the rack 37, so that when activated it transmits the vibration to the mass of material through the sections 40 and 41 of the rack and allows the clumps in the material to be broken down in order to make just the vibration of the rack sufficient to obtain the unloading of the material in area 39. Besides, despite the vibration and/or rotation of the rack 37, in the part underneath the rotation axis 38 the material may tend to accumulate so making the unloading incomplete. Should this inconvenience occur, it is compensated for by applying one or more vibrators 45 externally to and under the dump body 36 near the said rotation axis 38 of the rack.

The functioning of the active safety device 6 described above is obtained as follows. When unloading, the operator activates the raising of the dump body in the known way and the hydraulic elevation actuator cylinder 4 raises the dump body 2. The device 6, thanks to the connection on the axis 8 to the dump body, moves towards the working position in Figure 2, starting from the initial idle position in Figure 1 parallel to the frame and dump body. The end 12 of the struts 7 is guided inside the guides 10 and 11 and moves briefly from the idle position to the working one, as can be seen in the figures. As the inclination gradually increases the stopping components 13 advance with the end 12 of the struts 7: the spout 15 advances to every tooth 17 from the lack of resistance placed by the actuator cylinder 14 which allows the oscillation of the spout.

If the dump body is stopped during raising, the struts 7 of the safety device remain loaded as the stopping components 13 prevent the backwards

movement of the ends 12 of the struts 7. Only after having restarted the raising, and obviously unblocked the stopping components 13 by acting on the actuator cylinder 14, will lowering be possible: in this case the unblocking control on the actuator cylinders 14 will have to be maintained until the dump body has been lowered completely. However, by removing the unblocking control of the active safety device it is possible to stop the lowering at a desired height or also restart the elevation.

The functioning described above is extremely advantageous with the dump body at the maximum elevation. In fact, once the maximum elevation has been reached, that is, as shown in Figure 2, the struts 7 are at full stroke, but can still raise the dump body slightly to unblock the stopping components: the guides 10 and 11 are also short and prevent sticking; so, after unblocking, the dump body can be lowered. This condition allows the prevention of accidental lowering of the dump body as in the elevated position the front end of the dump body shifts the strain onto the hydraulic telescopic actuator cylinder or, if this has been retracted and the stopping components have been activated, also onto the struts of the safety device 6.

Therefore, also in the presence of erroneous and dangerous manoeuvres by the user, such as moving the dump truck with the load still present in the dump body in order to unload it, the safety is increased as it now also depends on the support action provided by the struts 7 to the dump body. Therefore in the worst working conditions there is the cooperation of the hydraulic telescopic actuator cylinder and the struts 7 of the safety device 6 to support of dump body.

The advantages obtained with this invention are as follows: the active safety device 6 is very simple to use, as the extraction takes place by pulling the dump body on the struts 7 in order to activate the stopping components 13 at the end 12 of the said struts. The activation takes place automatically should just the actuator cylinder 14 yield which, if maintained with light pushing pressure, ensures the subsequent engaging of the teeth 17 of the rack 18 between the guides 10 and 11. The lowering can be carried out with just the control of the operator or the clearance of the command and control devices for the dump body elevation, which are not described here being already well-

known in the prior art; accidental backwards movement, as happens at the beginning of structural yielding is prevented by the conformation of the stopping components. In addition, the maximum operability of the safety device depends on the maximum inclination that can be reached. At low or intermediate elevations the safety is ensured by the hydraulic telescopic actuator cylinder which, being only partially extracted, still has the respective telescopic sections in the housing, and therefore provides excellent resistance to strain. In fact, the mechanism of the blocking device 13, as shown, is activated only when a pre- established inclination of the struts is reached. Further still, the possibility of avoiding the occurrence of dangerous situations with the use of the passive safety devices, that is, to facilitate the unloading of the loose material that is loaded in the areas of the dump body 30 and 39 that are furthest from the unloading hatch 31 , is of great help as it avoids the formation of accumulations of material that are the well-known cause of yielding and accidents that happen to careless users. In fact, the inflatable cushion devices are easy to assemble and use, given that the action is carried out by means of the pressure of the liquid and its variation, which is a well- known way of remotely controlling the movements. In this case its use is advantageous, as the cushion is normally deflated, on loading the dump body, and is inflated as necessary to act with brief movements or pressure on the loose material on unloading. Then, the rotating rack and/or vibrating devices cause the agitating action on the clumped loose material to be concentrated on the formation point of the internal clumps. Once the clumps have been broken up, the loose material, if not particularly viscous inside, is easily unloaded. Only in the case of clumps under the rotation axis 38 does the action of the vibrators 45 on the outside and bed 9 of the dump body intervene in order to unload the clumps between the axis and the bed.

In practical implementation, the materials, dimensions and realisation details may be different from those indicated, but technically equivalent to them, in any case remaining within the legal field of the present invention. Thus, even if less advantageously, the unloading device provided with the rotation rack 37 for the rotation can be connected mechanically to an inclination component of the dump body 35 with respect to the frame 3 of the vehicle, in order to activate the rotation of the rack on increase in inclination of the dump

body.

Further still, also less advantageously, the rack 37 can be realised, simplifying it, only in the rotation version or only in the vibrating version, that is, immersed in the clumped material in the area 39 of the dump body in question, but only provided with the vibration, that is of the vibrator 44, or only rotation, which is controlled by the linear, cylinder 42 or rotating 43 actuators.

In addition, the rack may have a different position of the rotation axis 38 from that shown and/or may have only one or both the sections 40 and 41 with a direction near to horizontal, sub-horizontal, inclined, sub-vertical or vertical to act on the area 39 of the dump body.

Further still, the active safety device 6 may be realised with stopping components 13 and guides 10, 11 that are different from those shown but remaining within the field of the attached claims.

Finally, included in the invention are also dump trucks, lorries, articulated lorries and tractor-trailers, as well as "dumpers" or other means for the transport of loose material provided that they are equipped with rear tipper dump bodies and one or more of the safety devices described here.