This application claims convention priority from Australian provisional patent application 2013905072 filed on 24 Dec. 2013. The full contents of that Australian provisional patent application are hereby incorporated by this reference.
The present invention relates to a trailer door linkage suitable for use on a tipping trailer. Such tipping trailers are commonly used in the bulk transport industry.
The applicant's earlier international patent application PCT/AU2012/000546, published as WO 2012/155206, describes improvements to haul bodies and related apparatus. Such haul bodies include tipping trailers that include a movable sidewall or door through which payload may be dumped when the tub of the trailer is tipped. The sidewall is normally moved from the closed or travel position to the open position by at least one hydraulic actuator. The haul bodies as described in WO 2012/155206 are tipped using an air bag arrangement.
Considerably energy must be exhausted by the air bag arrangement (or other tipping linkage) to achieve full tipping of a haul body, particularly when the haul body is filled to maximum payload. The present invention seeks, in a first aspect, to preferably provide a mechanism for assisting tipping of the haul body when the sidewall or door is being opened. The present invention seeks, in a second aspect, to preferably control the rate of opening of the sidewall or door during initial tipping of the tub of the haul body.
The discussion of the background to the invention herein is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of this application.
According to a first aspect of the present invention there is provided a tipping linkage for a tub of a haul body, the tub including a side door pivotally attached thereto and the tub arranged for pivotal movement about a tub pivot axis, the tipping linkage including a first linkage connected to a sub-frame of the haul body and to a main linkage, the main linkage connected to a shaft connected to the tub, a door linkage connected to the main linkage and to a door connector, said first, main and door linkages arranged so that when tipping of the tub about the tub pivot axis is initiated by a tipping arrangement the door is moved from a closed position towards an open position, at least a part of a force loading on the door is transmitted to the door connector and converted to a lifting force to facilitate lifting of the tub away from the sub-frame.
In one embodiment, the main linkage includes a second linkage and a third linkage, the second linkage and the third linkage each connected to the shaft, the second linkage connected to the first linkage and the third linkage is connected to the door linkage.
Preferably, a break joint is established between the second and third linkages and is arranged so that when the break joint is established the second and third linkages function as a single extended linkage arranged to pivot about the shaft connected to the tub. When the break joint is broken, the second and third linkages are arranged to pivot independently of each other.
Preferably the door is pivotally attached to the haul body along a lower side of the door and about a pivot axis DP1. The lower side of the door being located generally adjacent the sub-frame of the haul body. The tub is preferably pivotally connected to the sub-frame along a pivot axis TP.
Preferably, the first linkage is arranged for pivotal connection to the sub-frame at a connection point S. Preferably, the first linkage is pivotally connected to the second linkage at connection point A. Preferably each of the second and third linkages are arranged for pivotal connection about the shaft. Preferably the third linkage is pivotally connected to the door linkage at connection point B. The door linkage, which is also described as a “fourth linkage” is preferably pivotally connected to the door connector at connection point C.
The door connector preferably includes any means for connecting movement of the door to the door (fourth) linkage. In accordance with a preferred embodiment, the door connector is integrally attached to the door and extends in a plane substantially parallel to an end wall of the tub.
In accordance with a preferred embodiment of the invention, the horizontal distance between connection point S and pivot axis point TP is about 1136 mm. The distance between connection point C and DP1 is about 306 mm. The first linkage has a length between centres of connection of about 642 mm, the second linkage has a length between centres of about 361 mm, the third linkage has a length between centres of about 833 mm and the fourth linkage has a length between centres of about 213 mm.
According to a second aspect of the present invention there is further provided a tipping linkage for a tub of a haul body with a side door pivotally attached thereto, the tub arranged for pivotal movement relative to a sub-frame, the tipping linkage including a first linkage connected to a sub-frame of the haul body and to a main linkage, the main linkage connected to a shaft connected to the tub, a door linkage connected to the main linkage and to a door connector, said first, main and door linkages arranged so that when tipping of the tub about the tub pivot axis is initiated by a tipping arrangement the door is moved from a closed position towards an open position.
Preferably, the main linkage includes a second linkage and a third linkage, the second linkage and the third linkage each connected to the shaft, the second linkage connected to the first linkage and the third linkage is connected to the door linkage.
The relative configuration of the first, main linkage and door linkage varies as the tipping linkage is operated resulting in the linkages adopting different angular positions with respect to each other and with respect to a sub-frame of the haul body. It will be appreciated that when the main linkage includes the second and third linkages, such linkages will also adopt different angular positions with respect to each other, the first linkage, and the door linkage as the tipping linkage is operated.
Preferably, controlled opening of the door from the closed position to the fully open position is achieved by the tipping linkage operating to vary the tub tip angle to door span angle ø ratio as the door opens and/or as the force loading on the door varies.
In accordance with an embodiment of the second aspect of the invention, the first to fourth linkages are arranged so that tipping of the tub between the angles of about 0-5° from the horizontal results in a higher rate of door opening than between the angles of about 5-10° from the horizontal.
In accordance with an embodiment where the main linkage includes the second and the third linkages, there may further be provided means for holding the second linkage and the third linkage together so that they operate as the extended main linkage. In accordance with one embodiment, the holding means is preferably a latch preferably arranged so that at a predetermined orientation of the tub, the latch is released so that the second linkage and third linkage become independent linkages.
Preferably, the latch is pivotally mounted on the end of the tub. An engagement pin is also preferably mounted on the end of the tub and positioned such that at the predetermined orientation of the tub, the latch engages with the engagement pin which thereafter results in the latch releasing the latching engagement between the second linkage and the third linkage.
Preferably, in accordance with either aspect of the invention, the first linkage is arranged to be extendable in length. In accordance with one embodiment, the first linkage includes a spring housing, a spring and an internal plunger. The main linkage is arranged for connection to the spring housing and the internal plunger has a first end arranged for connection to the sub-frame of the trailer. The first linkage is extendible by virtue of the plunger being extendible out of the spring housing and the extendible nature of the first linkage increases the permissible maximum tipping of the tub.
An embodiment of the invention may further include a return arrangement arranged to facilitate return of the tub to a travel position following pivotal movement of the tub to dump a payload. The return arrangement may adopt different forms, for example hydraulic or pneumatic actuators may be used. However, one preferred form includes an air bag arrangement and a mount. The air bag arrangement is configured so that when it is operated it will press against the mount and to drive the main linkage (or extended linkage) so as to return the tub to the travel position.
The invention also provides a method of operating a door of a tipping haul body including the steps of activating a tipping linkage in accordance with the first or second aspect of the invention.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
The tub base 20 is pivotally connected to a sub-frame 30 of a trailer chassis (not shown) so that the tub 10 can be pivoted to move between a travel position and a fully tilted/tipped position in which it is arranged to discharge payload through the door 16. The tub base 20 pivots about a longitudinal tub tipping axis extending through point TP and generally parallel to the length of the tub 10. The tub 10 as shown is arranged to be tipped by an air bag arrangement 40. However, it should be understood that the present invention is not intended to be limited to use with only such tipping arrangements. For example, the present invention could be used on a tipping trailer having a tub tipped by conventional hydraulic actuators.
The tipping linkage 100 includes a first linkage 120, a second linkage 140, a third linkage 160, a door or fourth linkage 180 and a door connector 200. The door connector 200 is either attached to or formed as part of the door 16 of the tub 10 and as illustrated extends adjacent to and parallel to the plane of the end wall 18 of the tub 10.
A tipping linkage 100 is preferably provided at each end of the tub 10. However, in other embodiments, a tipping linkage 100 is only provided at one end of the tub 10.
As best shown in
The second linkage 140 and the third linkage 160 are connectable by a break joint 230 established by joint surfaces 230a and 230b (
A second end 164 of the third linkage 160 is pivotally connected to a first end 182 of the fourth linkage 180 at connection point B. A second end 184 of the fourth linkage 180 is pivotally connected the door connector 200 at connection point C. The door connector 200 is pivotally connected about door pivot axis DP1 to the tube base 20 at a point distal to connection C. Door pivot axis DP1 extends generally parallel to tub tipping axis TP.
As shown in
It is envisaged that other floor slope angles may be adopted. For example, 10°, 11°, 12°, 14° and 15°.
The door 16 is normally held in the closed or travel position by at least one latch arrangement. Typically, each longitudinal end of the door 16 or door connection 200 includes a latch arrangement (not shown) that latches the same to keep the door 16 in the closed or travel position. If multiple latch arrangements are provided, then all need to be released before the door 16 of the tub 10 can be opened.
In order to dump a payload from the tub 10, the latch arrangements securing the door 16 in the closed or travel position are firstly released. Tipping of the tub 10 about tub tipping axis TP is then commenced by operation of the air bag arrangement 40. When the air bag arrangement 40 is actuated, the air bags extend applying upward pressure on the underside of the tub 10 (or tub base 20) at an area distal to the tipping axis TP. This results in the tub 10 and attached tub base 20 pivoting about the tipping axis TP and away from the sub-frame 30. As the tub 10 starts to tip, the unlatched door 16 is free to pivot about the door pivot axis DP1 and so the door 16 will start to move away from the position shown in
As the door 16 with attached door connector 200 pivots about DP1, a first end 202 of the door connector 200 rotates radially about axis DP1 (in a clockwise direction as viewed in
The further 5° tip of the tub base 20 also has the connections A, B and C moving from the positions shown in
It will be understood that the tub tip to door opening ratio is constantly changing as the span angle ø changes. At the beginning of a door opening sequence, there is minimal load on the door 16. However as the tub 10 tips, more and more of the payload within the tub 10 presses against the inner wall 16a of the door 16, making the “door” effectively heavier or increasingly loaded. The tipping linkage 100 accommodates the increased load on the door 16 by varying the ratio of tub tip to door opening. When the load on the door 16 is at a maximum, that is when the door 16 extends generally horizontally, the tub tip to door opening ratio needs to be at its lowest. It is envisaged that when the tub tip to door opening ratio is optimised through a range of door span angles ø, that the speed of the door 16 opening will be controlled, predictable and won't be subject to rapid acceleration.
Once the door 16 reaches the position shown in
As the air bag arrangement 40 continues to operate applying upward pressure on the underside of the tub 10, the break joint 230 breaks releasing the engagement between joint surfaces 230a and 230b. Once that engagement is released, the second linkage 140 and third linkage 160 become independent linkages and therefor act independently of one another.
As the tub 10 is caused to pivot about tub pivot axis TP, connection points A, B and C will be moved from the positions shown in
It will be appreciated that the tipping linkage 100 is arranged so that at least some of the energy of the door 16 as it moves from the position shown in
The operation of the tipping linkage 100 to assist with lifting of the tub 10 with attached tube base 12 is as follows:
As mentioned previously, the ratio of tip between the door 16 and the tub base 20 of an embodiment of the invention varies and is constantly changing as the tipping linkage 100 operates. In accordance with the above described embodiment, the ratio of about 11:1 is achieved when the third linkage 160 and second linkage 140 are generally parallel to one another (i.e. from about the position shown in
Although not illustrated in
Latch 500 is arranged to force the door 16 open initially, particularly in circumstances when the tub 10 has no payload to press against the door 16 to force opening when the tub 10 is tipped. The latch 500 prevents the door 16 from being initially stuck and then falling open at a later point in time out of schedule with the arrangement described in connection with
Latch 500 also provides and extra safety measuring as it ensures that the tub 10 cannot be tipped until the door 16 is unlatched and open.
As shown in
As shown in
First linkage 1120 has a first end 1122 arranged for pivotal connection to the sub-frame 30 of the tipping trailer at connection point S. A second part 1124 of the first linkage 1120 is pivotally connected at connection point A to a first end 1142 of the main linkage 1140. Main linkage 1140 is pivotally connected about a shaft 220 extending from and rigidly connected to the tub base 20. A second end 1164 of the main linkage 1140 is pivotally connected to a first end 1182 of the fourth linkage 1180. A second end 1184 of the fourth linkage 1180 is pivotally connected to the door connector 200 at connection point C. The door connector 200 and attached door 16 are pivotally connected about door pivot axis DP1 to the tub base 20 at a point distal to the connection C. Door pivot axis DP1 extends generally parallel to the tub tipping axis TP.
An air bag arrangement 1500 is mounted on the main linkage 1140. A T-mount 1600 is mounted on the end wall 18 of the tub 10 and is arranged, as will be explained below, to engage in certain instances with the air bag arrangement 1500.
The first linkage 1120 of this third embodiment of the invention adopts a different form to the first linkage 120 described in relation to the first embodiment of the invention. More particularly, the first linkage 1120 is an extendible length linkage which is provided to enable the tub 10 to be moved to the fully tilted or fully tipped position as shown in
The extendible first linkage 1120 includes a spring housing 2000, a spring 2020, an internal plunger 2030. Spring 2020 is located within the spring housing 2000 and is held between the spring housing 2000 and the internal plunger 2030.
The lower end of the internal plunger 2030 forms the first end 1122 of the first linkage 1120 and is arranged for pivotal connection to the sub-frame 30 of the tipping trailer at connection point S.
The second part 1124 of the first linkage 1120 includes a pair of stub axles 1124 axles extending either side of the spring housing 2000. A bearing block or low friction nylon bush 1125 connected to the main linkage 1140 enables the first end 1142 of the main linkage 1140 to be connected for rotation to the stub axles 1124.
As per earlier described embodiments of the invention, the door 16 of the tub 10 of the tipping trailer is normally held in the closed or travel position by at least one latch arrangement.
In order to dump a payload from the tub 10, the latch arrangement 800 securing the door 16 in the closed or travel position is firstly released. Tipping of the tub 10 about tipping axis TP is then commenced by operation of the tipping arrangement, which as illustrated includes an air bag arrangement 40. When the air bag arrangement 40 is actuated, the air bags extend applying upward pressure on the underside of the tub 10 and/or the underside of the tub base 20 at an area distal to the tipping axis TP. This results in the tub 10 and attached tub base 20 pivoting about the tipping axis TP and away from the sub-frame 30. As the tub 10 starts to tip, the unlatched door 16 will start to move away from the closed position (
As the door 16 begins to open and the tub 10 is lifted, the door connector 200 pulls on fourth linkage 1180 which in turns acts to pull up and rotate the main linkage 1140. The main linkage 1140 rotates clockwise (as viewed in
As the main linkage 1140 rotates between the position shown in
Main linkage 1140 pivots about shaft 220 until the air bag arrangement 1500 mounted on the main linkage 1140 strikes the T-mount 1600. At this point, further movement of the tub 10 from the position shown in
After the tub 10 reaches the position shown in
With the payload dumped from the tub 10, air from within the air bag arrangement 40 is released so as to lower the tub 10. The compressed spring 2020 within the spring housing 2000 which is no longer subject to load via the lift force of the air bag arrangement 40, drives the lowering of the tub 10. The expanding spring 2020 works to drive the tub 10 downwardly helping to drive air out of the air bag arrangement 40, which in turn causes lowering of the tub 10. The tub 10 moves downwardly towards the sub-frame 30 in this manner until the first linkage 1120 returns to its minimum length (
The compressed spring 2020 within the spring housing 2000 is effective to drive lowering of the tub 10 about ⅓ of the way back from the fully tipped position. Continued lowering of the tub 10 is achieved as air is released from the air bag arrangement 40 and also by operation of the air bag arrangement 1500. The air bag arrangement 1500 is expanded, for example, up to three times its closed length, to return the tub 10 to its normal travel position.
As per the first and second embodiments of the invention, the ratio of tip between the door 16 and the tub base 20 of the third embodiment of the invention varies and is constantly changing as the tipping linkage 1000 operates.
Embodiments of the invention are advantageous because tipping of the haul body is assisted by the action of the door opening. Further, door opening is controlled preventing damage to the door and any injury risk due to a rapid door opening event.
The embodiments have been described by way of example only and modifications within the spirit and scope of the invention are envisaged.
Number | Date | Country | Kind |
---|---|---|---|
2013905072 | Dec 2013 | AU | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/AU2014/001158 | 12/23/2014 | WO | 00 |