AU2015230763A1

AU2015230763A1 - Drawbar and drawbar assembly

Info

Publication number: AU2015230763A1
Application number: AU2015230763A
Authority: AU
Inventors: Dean REHN; Luke Taylor; David Wallace
Original assignee: Fortescue Metals Group Ltd
Current assignee: Fortescue Ltd
Priority date: 2015-09-23
Filing date: 2015-09-23
Publication date: 2017-04-06
Also published as: WO2017049340A1

Description

H:\txb\Interwoven\NRPortbl\DCC\TXB\8511493_l.docx - 23/9/15 2015230763 23 Sep 2015 - 1 -

DRAWBAR AND DRAWBAR ASSEMBLY

This invention relates to a drawbar assembly for coupling of rail cars, whereby coupled cars can rotate with respect to one another, such as required in mining industries during dumping operations. 5 Couplings between rail cars used in mining industries for transporting materials, typically use traditional interlocking knuckle connections. During dumping of material, it is desirable to have couplers that are rotatable, so that individual cars (or cars in pairs) can be rotated for dumping without the need to disconnect them from one another first. Such a rotatable coupling may involve a fixed coupler attached to one car, knuckles and a rotary 10 coupler attached to a second car that can pivot relative to the car to which it is attached. An alternative coupling between cars is a non-rotatable coupling provided by way of a fixed draw bar which couples together adjacent cars but does not enable relative rotational movement between the cars.

One result of these existing forms of couplings is that only two cars can be coupled 15 together in a single set as the cars need to be able to rotate in pairs in an unloader in the form of a rotary dumper, requiring that every second coupling of the cars is a rotatable coupling (formed of a fixed coupler - a coupler which is fixed from rotating relative to one car - and a rotary coupler - a coupler which is rotatable relative to the adjacent car). The fixed coupler and the rotary coupler are releasably coupled together by way of knuckles, 20 however the applicant has identified that these knuckles are prone to breakage and that the incidence of broken knuckles means a lower degree of safety, resulting in significant operational and maintenance costs. There are existing examples of 4 to 6 car sets, though these arrangements use bottom discharge unloading and do not pass through a rotary dumper. 25 Examples of the invention seek to provide a coupling arrangement that allows for increased reliability in couplings between cars. Examples of the invention may also seek to provide an increase in the number of cars in a set that are permanently coupled (for example 4 to 10 cars) where pairs of cars can be rotated together for dumping. Examples H:\txb\Interwoven\NRPortbl\DCC\TXB\8511493_l.docx - 23/9/15 2015230763 23 Sep 2015 -2- of the invention may even be used to provide an arrangement in which an increased number of cars is permanently coupled and each car can be rotated individually for dumping.

According to a first aspect of the invention, there is provided a rotary drawbar assembly 5 for coupling rail cars, comprising a drawbar extending between housings each adapted to be fixed to a respective one of the cars, the connection between one end portion of the drawbar and the associated housing comprising a collar rotatably mounted in the housing and a pivot pin mounting the end portion within the collar for pivotal movement relative thereto about an axis transverse to the rotational axis of the collar. 10 In a preferred form, contacting surfaces of the rotatable collar and housing are of different hardnesses.

Preferably, the different hardnesses are obtained by a hardening treatment. Preferably, the hardening treatment is flame hardening.

In accordance with another aspect of the present invention, there is provided a drawbar for 15 coupling together cars wherein the drawbar is formed as an elongated unitary part having a first end and a second end opposite the first end, wherein the first end is adapted to rotate relative to a rotary yoke when the first end is coupled relative to the rotary yoke and wherein the second end is adapted to be restrained from rotation relative to a fixed yoke when the second end is coupled relative to the fixed yoke. 20 In accordance with another aspect of the present invention, there is provided a drawbar for coupling together cars wherein the drawbar is formed as an elongated unitary part having a first end and a second end opposite the first end, wherein the first end is shaped to rotate relative to a rotary yoke when the first end is coupled relative to the rotary yoke and wherein the second end is shaped to be restrained from rotation relative to a fixed yoke 25 when the second end is coupled relative to the fixed yoke.

In accordance with another aspect of the present invention, there is provided a drawbar for coupling together cars wherein the drawbar is formed as an elongated unitary part having a H:\txb\Interwoven\NRPortbl\DCC\TXB\8511493_l.docx - 23/9/15 2015230763 23 Sep 2015 -3- first end and a second end opposite the first end, wherein the first end is rounded relative to the second end whereby the first end is able to rotate relative to a rotary yoke when the first end is coupled to the rotary yoke and whereby the second end is restrained from rotation relative to a fixed yoke when the second end is coupled to the fixed yoke. 5 A preferred embodiment of the invention will now be described by way of non-limiting example only with respect to the accompanying drawings, in which:

Figure 1 is a plan view of a rotary drawbar and yoke arrangement;

Figure 2 is a cross sectional view on line A-A of Figure 1;

Figure 3 is a side view of Figure 1; 10 Figure 4 is a perspective view of a rotary drawbar in accordance with one example;

Figure 5 is a top view of the rotary drawbar shown in Figure 4;

Figure 6 is a perspective view of a rotary drawbar in accordance with another example;

Figure 7 is a top view of the rotary drawbar shown in Figure 6; 15 Figure 8 is a side view of the rotary drawbar shown in Figure 6; and

Figure 9 is an end view of the rotary drawbar shown in Figure 6.

Figures 1, 2 and 3 show a preferred embodiment of the invention, in which a rotary drawbar assembly for attaching two cars has a fixed joint at one end and a rotary joint at the other end. This embodiment comprises rotary drawbar 1 coupled at one end with a 20 yoke and draft gear assembly 4 by a connecting pin 3, and at the other end with a yoke and draft gear assembly 5 by a connecting pin 2. The connecting pins 2 and 3 permit pivotal movement of the drawbar about the axis of the pin. The draft gear assembly absorbs longitudinal forces by cushioning switching impacts such that the impacts do not damage H:\txb\Interwoven\NRPortbl\DCC\TXB\8511493_l.docx - 23/9/15 2015230763 23 Sep 2015 -4- the car components. The construction and operation of the draft gear assembly will be well understood by those skilled in the art.

Each yoke and draft gear assembly comprises an outer yoke forming a housing within which the draft gear is mounted. More particularly, the assembly 4 comprises a yoke 4a 5 and draft gear 4b, and the assembly 5 comprises a yoke 5a and draft gear 5b. The connecting pin 3 by which one end of the drawbar is connected to the assembly 4 is mounted to a collar 8 which itself is rotatably mounted within the yoke 4a for rotation about the axis of the yoke 4a. As such, it will be convenient to refer to the yoke 4a as a rotary yoke even though it does not itself rotate relative the car on which it is mounted 10 (although it does of course allow rotation of a rotary coupler mounted in the rotary yoke).

In contrast, the connecting pin 2 by which the other end of the drawbar is connected to the assembly 5 does not rotate within the yoke 5a, and hence it is convenient to refer to the yoke 5a as a fixed yoke (which is typically fitted with a fixed coupler which is not able to rotate relative to the fixed yoke). Carrier plates 9 attached to the yokes 4a and 5a are for 15 the purpose of mounting the assemblies to the rail cars.

During dumping of the contents of the car at the fixed yoke end of the drawbar 1, the entire fixed yoke and draft gear assembly 5 rotates with the rotary drawbar 1. These components all rotate relative to the rotary yoke by virtue of rotation of the collar within the rotary yoke 4a. Conversely, during dumping of the car at the rotary yoke end of the drawbar 1, the 20 rotary yoke and draft gear assembly 4 rotates together with the car, while drawbar 1, fixed yoke and draft gear assembly 5, and the car to which the fixed yoke 5a is attached do not rotate.

When the collar 8 rotates with respect to rotary yoke 4a and the collar and yoke are formed of similar materials of similar hardness, there can be a significant wear that occurs due to 25 galling. This occurs where similar metals are worn against each other under pressure such that the metals bond (weld) to each other at asperities, generating wear debris which accelerates further wear and reduces the working life of the rotary yoke. Since the rigid drawbar is connected at both ends to a car, there is very little freedom for vertical movement to counteract these pressures, unlike in previous examples of knuckle H:\txb\Interwoven\NRPortbl\DCGTXB\85l l493_l.docx - 23/9/15 2015230763 23 Sep 2015 -5- connection, which provided sufficient freedom of movement. This is particularly the case where an empty car is adjacent a full car, where the full car is typically lower in height under the weight of its contents. When one of the two cars is located within a rotary dumper while attached to the other, this slight difference in height can result in greater 5 interference between components during rotation, increasing the wear effect. Preferred embodiments seek to address this problem by employing flame hardening of the collar to create a differential hardness at the interface between the collar and the yoke to eliminate, or at least reduce, galling. However, other forms of hardening treatment to create differential hardening can alternatively be used. A further alternative is hardening of the 10 yoke rather than the collar to attain the required differential hardness.

The rotary drawbar assembly particularly described enables a set of rail cars, for example four to ten, to be permanently coupled.

Advantageously, replacement of previous knuckle-type connections between rail cars also results in a significant weight reduction, for example from a typical weight of 475kg of 15 couplers to 200kg of the rotary drawbar, making operations significantly more efficient through reduced fuel requirements.

Although the embodiments of the invention are described above, each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the 20 present invention without departing from the scope or spirit thereof. For example, although the drawbar assembly particularly described consists of a rotary yoke at one end and a fixed yoke at the other end, it would in principle be possible to have a rotary yoke at each end, however such an arrangement may be unnecessary and problematic as the presence of a single rotary yoke (that is, the ability for just one end of the drawbar to 25 rotate) provides sufficient rotational capability between cars required for rotation at the rotary dumpers, without allowing for unwanted rotation of the drawbar which could result in difficulties in removing the drawbar.

Advantageously, the present invention may facilitate reductions in weight, reductions in H:\txb\Interwoven\NRPortbl\DCGTXB\8511493_l.docx - 23/9/15 2015230763 23 Sep 2015 -6- cost, increased production, as well as improvements in reliability resulting in less downtime of machinery. Examples of the present invention may also facilitate coupling together of cars in fixed units of greater length, for example units of 4 cars, 6 cars, 8 cars or 10 cars. 5 With reference to Figures 4 to 9, Figures 4 and 5 show a rotary drawbar 1 in accordance with one example of the present invention and Figures 6 to 9 show a rotary drawbar 1 in accordance with another example of the present invention. Both drawbars operate in a similar manner, and like features have been numbered with like reference numerals. However, as can be seen, there are differences in the shapes, with the second drawbar (of 10 Figures 6 to 9) having larger cutaway portions at a neck of a first end, the first end being adapted for rotation within a rotary yoke.

More specifically, Figures 4 to 9 show a drawbar 1 for coupling together cars wherein the drawbar 1 is formed as an elongated unitary part having a first end 10 and a second end 12 opposite the first end 10, wherein the first end 10 is adapted to rotate relative to a rotary 15 yoke 4 when the first end 10 is coupled relative to the rotary yoke 4 and wherein the second end 12 is adapted to be restrained from rotation relative to a fixed yoke 5 when the second end 12 is coupled relative to the fixed yoke 5. As can be seen, the first end 10 is more rounded in shape to rotate relative to the rotary yoke 4 when the first end 10 is coupled relative to the rotary yoke 4 whereas the second end 12 is relatively square in 20 shape to be restrained from rotation relative to the fixed yoke 5 when the second end is coupled relative to the fixed yoke 5. The first end 10 is rounded relative to the second end 12, possibly by replicating a portion of a shape of a rotary coupler.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will 25 be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or 2015230763 23 Sep 2015 H:\txb\Interwoven\NRPortbl\DCC\TXB\8511493_l.docx - 23/9/15 -7- admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.

While various embodiments of the present invention have been described above, it should 5 be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS

1. A rotary drawbar assembly for coupling rail cars, comprising a drawbar extending between housings each adapted to be fixed to a respective one of the cars, the connection between one end portion of the drawbar and the associated housing comprising a collar rotatably mounted in the housing and a pivot pin mounting the end portion within the collar for pivotal movement relative thereto about an axis transverse to the rotational axis of the collar.
2. The rotary drawbar assembly according to claim 1, wherein contacting surfaces of the rotatable collar and housing are of different hardnesses.
3. The rotary drawbar assembly according to claim 2, wherein the different hardnesses are obtained by a hardening treatment.
4. The rotary drawbar assembly according to claim 3, wherein the hardening treatment is flame hardening.
5. The rotary drawbar according to any one of the preceding claims, further comprising a draft gear between the said end portion of the drawbar and the housing to absorb longitudinal forces.
6. The rotary drawbar according to any one of the preceding claims, wherein the housing consists of a yoke.
7. The rotary drawbar according to any one of the preceding claims, wherein the other end portion of the drawbar is connected to its associated housing by a pivot pin for pivotal movement relative thereto about an axis transverse to the longitudinal axis of the drawbar.
8. The rotary drawbar as claimed in any one of the preceding claims, wherein the drawbar is formed as a unitary part.
9. The rotary drawbar as claimed in claim 8, wherein the drawbar is forged.
10. A rotary drawbar assembly including a drawbar, a rotary yoke mounted to one car and a fixed yoke mounted to a second car, wherein a first end of the drawbar is coupled to the rotary yoke and a second end of the drawbar opposite the first end is coupled to the fixed yoke, and wherein the first end of the drawbar is adapted to allow rotation of the drawbar relative to the rotary yoke.
11. A rotary drawbar assembly as claimed in claim 10, wherein the first end of the drawbar is shaped to allow rotation of the drawbar relative to the rotary yoke.
12. A rotary drawbar assembly as claimed in claim 11, wherein the first end of the drawbar is rounded to allow rotation of the drawbar relative to the rotary yoke.
13. A rotary drawbar assembly as claimed in claim 12, wherein the first end of the drawbar is rounded relative to the second end of the drawbar.
14. A rotary drawbar assembly as claimed in any one of claims 10 to 13, wherein the drawbar is formed as a unitary part.
15. A drawbar for coupling together cars wherein the drawbar is formed as an elongated unitary part having a first end and a second end opposite the first end, wherein the first end is adapted to rotate relative to a rotary yoke when the first end is coupled relative to the rotary yoke and wherein the second end is adapted to be restrained from rotation relative to a fixed yoke when the second end is coupled relative to the fixed yoke.
16. A drawbar for coupling together cars wherein the drawbar is formed as an elongated unitary part having a first end and a second end opposite the first end, wherein the first end is shaped to rotate relative to a rotary yoke when the first end is coupled relative to the rotary yoke and wherein the second end is shaped to be restrained from rotation relative to a fixed yoke when the second end is coupled relative to the fixed yoke.
17. A drawbar for coupling together cars wherein the drawbar is formed as an elongated unitary part having a first end and a second end opposite the first end, wherein the first end is rounded relative to the second end whereby the first end is able to rotate relative to a rotary yoke when the first end is coupled to the rotary yoke and whereby the second end is restrained from rotation relative to a fixed yoke when the second end is coupled to the fixed yoke.
18. A drawbar assembly substantially as hereinbefore described with reference to the accompanying drawings.
19. A drawbar substantially as hereinbefore described with reference to the accompanying drawings.