TRANSPORT VEHICLE WITH CONTAINER UNLOADING DEVICE PROVIDED WITH WEIGHING MEANS

Abstract: Transport vehicle (1) with a loading space provided with a loading opening (3) and a container unloading device (4) comprising a container carrier (6), provided with gripping means (9) for gripping and suppor­ ting a container on a side and lifting means (15) connected to the container carrier for raising the container carrier to the loading opening. The container carrier comprises a first sub­ frame (25) directly connected to the lifting means and, connected to the first sub-frame by vertical guiding means (8), a second sub-­ frame (32) bearing the gripping means, wherein the vertical guiding means permit only an at least practically vertical, parallel displacement of the second sub-frame relative to the first, and on one of both sub-frames a force sensor (34) is arranged on which the other sub-frame lies gripping in a downward direction and wherein processing means connected to the force sensor are arranged which can process an output signal delivered by the force sensor into a weight-value.

Description: The invention relates to a container carrier as defined in the introductory part of claim 1. A transport vehicle provided with such a container carrier is known from DE-U-8 707 422 and is used for example for emptying waste containers and taking away the waste. Under the motto "the polluter pays" there is a need to charge the producer of waste costs that are proportional to the amount of waste tendered. This applies particularly to waste that is highly polluting to the environment such as industrial waste and in particular certain types of chemical waste. With a container carrier of the type described in the preamble the amount of waste present in each container for unloading can be determined. In this known device the second sub-frame is connected to the first sub-frame by spring elastic elements, which can be rubber blocks or leaf springs. The force detected by the force sensor therefore is dependent on the relative position of the second sub-frame with regard to the first sub-frame. Furthermore the force detected by the force sensor is dependent on possible permanent deformation of the spring elastic means and the detected force is also dependent on the spring constant of each of the elements, which spring constant might very from element to element. Accordingly it is difficult to obtain a proper weight-value from the output signal of the force sensor. A reliable operation is very much dependent on a regular calibration of the system. In the day to day practice of a transport vehicle of the present kind, this careful and regular calibration can not be guaranteed, so that the reliability of the operation of the weighing system is questionable. The object of the invention is to provide a device of the kind set forth above, which does not have these disadvantages. According to the invention this is obtained with the measures as defined in the characterizing portion of claim 1. As soon as a container is lifted from the ground by the container carrier, the weight of the container acts on the force sensor via the second sub-frame. This force sensor thereby provides an output signal which is representative for the load and can be processed by the processing means into a weight-value. The vertical guiding means take up all other than practically vertical forces so that the force sensor is loaded purely in one direction. Despite the fact that the container carrier grips the container on one side and the centre of gravity of the container with the waste lies a considerable distance in front of the container carrier, a reliable weighing can nevertheless be achieved in this manner. In practice the transport vehicle will of course not always be disposed absolutely horizontally and therefore the vertical guiding means will not always transmit a wholly absolute vertical load to the force sensor. It has been found however that the variations thereby occurring in practice lie within acceptable limits. A particularly favourable embodiment is characterized in claim 2. It has been found that the use of linear ball bearings enables a very sensitive weighing. The friction in the system is very limited so that errors as a result of "snagging" of the guiding are very small. A preferred embodiment is characterized in claim 3. The second sub-frame is supported herein on four points situated at a considerable mutual distance so that a good, stable and operationally reliable device is obtained. By application of the feature in claim 4 the force sensor is protected against overloading and moreover the maximum relative displacement of both sub-frames remains very limited whereby the operators of the transport vehicle according to the invention are not hampered by uncontrolled movements of the container. The invention also relates to and provides a transport vehicle as characterized in claim 5. The container carrier according to the invention can replace an existing container carrier without weighing. device in a favourable manner in order to convert a transport vehicle with a known container unloading device to a transport vehicle according to the invention. The invention will be further elucidated below with reference to the embodiment shown in the figures. Fig. 1 shows a partly perspective view of a transport vehicle according to the invention; fig. 2 shows a partly perspective view, with broken away portions according to arrow II in fig. 1, of the container carrier according to the invention. The transport vehicle 1 is a freight vehicle with a load container 2 which has a loading opening 3 on the top. In the vicinity of the loading opening 3 is arranged a container unloading device 4, using which a container 5 can be emptied into the load container through the loading opening 3. The container loading device 4 comprises a container carrier designated in its entirety by 6. The container carrier 6 is provided with a comb 9 with upward protruding parts which can engage under an edge 11 on the side of the container 5. The container carrier is further provided with a support 10 which can support the container 5 at the side. The container carrier has rolls 7 which fall into channels 19 of U-profiles arranged on the vehicle 1. The container carrier 6 can hereby move upward with a container 5 picked up on the comb 9 and supported by the support 10 in order to deposit the contents of the container 5 through the loading opening 3 into the load container 2. To this end the container carrier 6 is connected to lifting means 15 comprising an arm construction 16 which is mounted on the upper surface of the load container 2. Engaging onto the arm construction 16 are two hydraulic cylinders 17 which when set into operation can swivel the arm construction 16 upward as seen in fig. 1 in clockwise direction. On a part of the arm construction 16 protruding downward between the U-profiles 8 are pivotally mounted two pull rods 18 which in their turn are pivotally connected with a bottom end to the container carrier 6. By activating the cylinders 17 the arm construction 16 thus swivels upward and the container carrier 6 moves upward into the U-profiles 8. A container 5 gripped on the comb 9 is thereby moved upward. As soon as the upper rolls 7 of the container carrier 6 arrive in the top horizontal portion of the U-profiles 8 the container carrier 6 tilts and therewith the container 5. With continued movement the container 5 tilts so far that the contents pour through the loading opening 3 into the load container 2. In typical manner a cover co-acting with the loading opening 3 can be connected to the arm construction 16 such that in the position drawn in fig. 1 the loading opening 3 is closed off by this cover. Fig. 2 shows the container carrier 6 in more detail. The container carrier comprises a first sub-frame 25 on which are mounted the above mentioned rolls 7. Arranged at the rear of the first sub-frame 25 as seen in fig. 2 is a rectangular plate 26 on the four corners of which are mounted supports 27 for two rods 28. The supports 27 are arranged such that the rods 28 extend parallel to one another and vertically in the position of use shown in fig. 1. To obtain a minimum depth of the container carrier the rods extend through the profiles of the first sub-frame 25. As is shown at bottom left in fig. 1, sleeves 29 through which the rods 28 extend are welded fixedly in the lower profile 30. Two sliding pieces 31 comprising per se known linear ball bearings are mounted on each rod 28. These linear ball bearings can slide over the rods 28 with minimal friction. Each sliding piece 31 further comprises a support on which is mounted a second sub-frame 32 which bears the gripping means for the container. Mounted on the first sub-frame 25, in particular on the lower profile 30 thereof, is a per se known force sensor 34. This force sensor 34 is of the freely suspended rod type and is fixedly connected to the profile 30 at the left-hand end as seen in fig. 2. The right-hand end protrudes freely suspended and is provided in an upper surface with a recess for a ball 35. On this ball can rest a support 33 which in turn is connected as a whole to the second sub-frame 32. The sliding pieces 31 are mounted at positions on the second sub-frame 32 such that the second sub-frame 32 can perform a limited vertical stroke relative to the first sub-frame 25. In upward direction the sub-frame 32 can move so far that the upper sliding pieces come into contact with the upper profile functioning as stop so that the support 33 just disengages from the ball 35. In this case the force sensor 34 is therefore entirely free of load. The lower sliding pieces 31 are arranged at a position such that when they come into contact with the lower beam 30 likewise functioning as stop the force sensor 34 is loaded to the allowable maximum, that is, with the maximum allowable deflection. The total vertical stroke of the second sub-frame relative to the first sub-frame amounts to a maximum of several millimetres. As fig. 2 also shows, a plate 37 is welded at the height of each support 27 to the upper beam on the side opposite the plate 26 wherein each plate 37 bears two pressure bolts 38 which press the supports 27 more fixedly against the plate 26. Since a container picked up on the comb 9 has a centre of gravity located considerably outside the plane defined by the rods 28 a fairly great moment is exerted on the rods 28 which is transmitted onto the supports 27. The bolts 38 help to absorb the load hereby occurring. The invention is not limited to a transport vehicle with a side container unloading device as shown in fig. 1. The invention is equally applicable in a transport vehicle with a container unloading device at the rear, wherein the loading opening is situated in a rear surface of the load container. A container carrier comprising two sub-frames connected to one another by vertical guiding means and wherein a force sensor can measure the load of the first sub-frame relative to the second can be arranged on existing transport vehicles of the present sort to replace the containers already in use thereon. When the transport vehicle comprises a type of container unloading device other than described here the container carrier will be otherwise embodied in a corresponding manner. With the said rear container unloading device a container carrier is not picked up in U-profiles so that in that case the first sub-frame will also not be provided with rolls.

Claims: Container carrier (6) for a transport vehicle with a loading space having a loading opening and a container unloading device provided with lifting means for raising the container carrier to the loading opening, said container carrier comprising gripping means for gripping and supporting a container on a side thereof, a first sub-frame (25) for connection to the lifting means and, connected to said sub-frame by vertical guiding means (28), a second sub-frame (32) bearing the gripping means wherein the vertical guiding means only permit a vertical, parallel displacement of the second sub-frame relative to the first one and wherein on one of both sub-frames a force sensor (34) is arranged upon which the other sub-frame lies engaging in downward direction and that processing means connected to the force sensor are arranged which can process an output signal delivered by the force sensor into a weight-value, characterized in that the vertical guiding means (18) comprise vertical rods mounted parallel at a distance relative to one another on one of the sub-frames and sliding pieces (31) mounted on the other sub-frame and mounted slidably on the rods. Container carrier as claimed in claim 1, charac- terized in that the sliding pieces are mounted with linear ball bearings on the rods. Container carrier as claimed in claim 1 or 2, characterized in that two parallel vertical rods are used and that two sliding pieces are mounted on each rod at a mutual distance. Container carrier as claimed in any of the foregoing claims, characterized in that stop means are arranged which bound the stroke of the one sub-frame relative to the other on the one side to a position wherein the force sensor is just free of load and on the other side to a position wherein the force sensor undergoes its maximum allowable deformation. Transport vehicle with a loading space having a loading opening and a container unloading device provided with lifting means connected to a container carrier according to anyone of the foregoing claims, for raising the container carrier to the loading opening.

Inventors: VERSTEEG, JAN HENDRIK
Applicants: TERBERG MACHINES B.V.
Application year: 1990
Main classification: B65F3
IPC codes: B65F3