BACKGROUND

The invention relates to a towing arrangement for a mine machine .

The invention further relates to a mine machine .

For safety reasons , many mine machines use hydraulically- released brake systems to provide automatic fail-safe braking on loss of vehicle power or hydraulic fluid pres sure . Such brakes prevent a disabled machine from easily being towed . In order to tow the disabled machine easily, it is known to provide towing or retrieval hook of such a mine machine with a releasing arrangement that releases brake when the machine is towed from the hook, thus per mitting the towing of the disabled mine machine .

However, existing releasing arrangements are often large and their structure susceptible to be damaged in harsh en vironment of mines .

BRIEF DESCRIPTION

Viewed from a first aspect, there can be provided a towing arrangement for a mine machine, comprising

- a body part,

- a towing element for allowing a towing tool to be con nected to the towing arrangement,

- the towing element being attached to the body part,

- a hydraulic actuator,

- a first part of the hydraulic actuator attached to the body part, and

- a second part of the hydraulic actuator attachable to a support element,

-the support element, when the towing arrangement being attached to the mine machine, being fixed to said mine ma chine, - the body part being arranged movable in relation to the support element,

- the body part being arranged to move in relation to the support element when a towing force is affecting to the towing element, and

- the hydraulic actuator is arranged to get shorter along with said towing force affecting to the towing element, wherein

- the hydraulic actuator comprises connectors for connec tion to a hydraulic circuit of a braking system of the mine machine, and

- hydraulic pressure created in the hydraulic actuator due to the towing force affecting to the towing element is ar ranged to release brakes of the mine machine .

Thereby a towing arrangement for a mine machine being com pact in size and easy to arrange, even to retrofit, in a mine machine may be achieved .

Viewed from a further aspect, there can be provided a mine machine comprising the towing arrangement mentioned above .

Thereby a mine machine the towing arrangement of which is compact in size and well protected may be achieved .

The arrangement and the method are characterised by what is stated in the independent claims . Some other embodi ments are characterised by what is stated in the other claims . Inventive embodiments are also disclosed in the specification and drawings of this patent application . The inventive content of the patent application may also be defined in other ways than defined in the following claims . The inventive content may also be formed of sever al separate inventions , especially if the invention is ex amined in the light of expressed or implicit sub-tasks or in view of obtained benefits or benefit groups . Some of the definitions contained in the following claims may then be unnecessary in view of the separate inventive ideas . Features of the different embodiments of the invention may, within the scope of the basic inventive idea, be ap plied to other embodiments .

In one embodiment , the towing element comprises a hook . An advantage is that the hook is easy and fast to use in tow ing .

In one embodiment, the hydraulic actuator 3 comprises a hydraulic cylinder . An advantage is that hydraulic cylin ders have a simple structure and they are straightforward ly adaptable to the arrangement .

In one embodiment, the arrangement comprises at least two hydraulic actuators . An advantage is that smaller actua tors may be used without compromising volume flow of hy draulic fluid created by the arrangement and fed in the braking system of the mine machine .

In one embodiment, the arrangement comprises at least two hydraulic actuators being arranged symmetrically in rela tion to a longitudinal axis of the arrangement . An ad vantage is that a stable movement of the frame may be achieved .

In one embodiment, the body part comprises at least one extension arranged to extend sideward in relation to the longitudinal axis of the arrangement, the first part of the hydraulic actuator being attached to the extension, and the extension being arranged to forward the movement of the towing element in the hydraulic actuator . An ad vantage is that the hydraulic actuator may be arranged laterally in relation to the frame, and thus the length of the arrangement reduced . In one embodiment, the arrangement comprises a returning element arranged to return the body part in its initial position in relation to the support element when towing element is released from the towing force . An advantage is that the body part may return quickly to the original po sition as before starting the towing action and the brakes of the mine machine go on . In one embodiment, the returning element comprises at least one spring element . An advantage is that spring ele ments are simple and cost-effective mechanical parts .

In one embodiment, the arrangement comprises a stopper ar- rangement for transferring towing forces from the body part to the frame of the machine . An advantage is that the forces do not focus on the hydraulic actuator and/or the returning element . In one embodiment, the hydraulic actuator is arranged at least substantially parallel to a moving direction of the body part . An advantage is that the movement of the body part is transferred directly to the actuator . In one embodiment, the hydraulic actuator comprises con nectors for connection to a hydraulic circuit of a braking system of the mine machine , and wherein hydraulic pressure created in the hydraulic actuator due to the towing force affecting to the towing element is arranged to release brakes of the mine machine . An advantage is that the ar rangement controls the braking system in a simple way .

In one embodiment, the support element comprises attaching means for attachment the support element to the mine ma- chine . An advantage is that the support element may be manufactured separate from the structure of the mine ma chine .

In one embodiment, the arrangement is formed into a struc tural module retrofittable in a mine machine . An advantage is that mine machines without the towing arrangement may be equipped with the arrangement .

In one embodiment , a frame part of the mine machine is ar ranged to perform as the support element . An advantage is that the structure of the towing arrangement may be sim plified.

BRIEF DESCRIPTION OF FIGURES

Some embodiments illustrating the present disclosure are described in more detail in the attached drawings , in which

Figure 1 is a schematic view of a part of a mine machine , and

Figures 2a - 2d are schematic views of a detail of an ar rangement in partial cross-section.

In the figures , some embodiments are shown simplified for the sake of clarity . Similar parts are marked with the same reference numbers in the figures .

DETAILED DESCRIPTION

Figure l is a schematic view of a part of a mine machine .

The mine machine 6 may be e.g. a wheel loader . However, the mine machine 6 may be any type of a mining vehicle or a construction vehicle . The mine machine 6 may be provided with one or more working devices for executing designed work tasks at the work site . Thus , the mine machine 6 may also be a transport vehicle or dumper, a rock drilling rig, a bolting or reinforcing machine or a measuring ma chine, for example .

The mine machine 6 comprises a towing arrangement 100 for towing the machine . The towing arrangement 100 comprises a body part (not shown in Figure 1 ) and a towing element 2 for allowing a towing tool to be connected to the towing arrangement 100 and thereby to the mine machine 6.

The towing arrangement 100 is further provided with a hy draulic actuator (not shown In Figure 1 ) that comprises a first part attached to the body part, and a second part attachable to a support element 5.

The support element 5 is fixed to the mine machine 6. In an embodiment, a frame part 12 of the mine machine 6 is arranged to perform as said support element 5. In another embodiment, the support element 5 is an additional ele ment, i.e. not a part of the frame of the mine machine 6, that comprises attaching means by which the support ele ment can be attached to the mine machine 6. The attaching means may comprise e.g. bolts or screws and corresponding holes . Thus , the arrangement 100 may be a structural mod ule that is retrofittable in mine machines .

The body part is movable in relation to the support ele ment 5 in moving directions M so that the body part moves in relation to the support element 5 when a towing force is affecting to the towing element 2.

The structure and the features of the towing arrangement 100 are described more detailed in connection with the following figures . Figures 2a - 2d are schematic views of a detail of an ar rangement in partial cross-section. The arrangement 100 has been arranged to a mine machine 6, in close proximity of a radiator of a cooler arrangement 15 of the mine ma chine . However, the proximity to the radiator is not nec essary, i.e. the function of the arrangement 100 is not dependent on the radiator .

In some embodiments , such as shown in Figures , the towing element 2 comprises a hook . In some another embodiments , the towing element is other type of element, such as a loop .

In an embodiment, the hydraulic actuator 3 comprises a hy draulic cylinder that is arranged at least substantially parallel to a moving direction M of the body part 1. The hydraulic actuator is arranged to get shorter along with towing force affecting to the towing element 2.

According to an aspect of the invention, the hydraulic cylinder is connected to the hydraulic circuit of the braking system of the mine machine 6 so that hydraulic fluid may flow from the hydraulic cylinder to said hydrau lic circuit and vice versa . The connection may comprise hydraulic hoses , couplings etc .

In an embodiment , a piston side chamber, i.e. side oppo site to a chamber of piston rod side, of the hydraulic cylinder is connected to the hydraulic circuit of the braking system of the mine machine 6. Volume of the piston side chamber is larger because the volume is not limited by piston rod, and thus a large volume flow of pressure fluid out from the cylinder is achieved compared to outer dimensions of the cylinder . This makes it possible to use smaller cylinders in the arrangement 100. In an embodiment, there are at least two hydraulic actua tors 3 arranged parallel in the arrangement 100, as in the embodiment shown in the Figures . The hydraulic actuators 3 may be arranged symmetrically in relation to a longitudi nal axis X of the arrangement . In another embodiment, the hydraulic actuators 3 , or just one hydraulic actuator 3 , is/are arranged asymmetrically in relation to a longitudi nal axis X of the arrangement .

First part 4a of the hydraulic actuator is attached to ex tension 7 of the body part 1. The extension 7 extends sideward in relation to the longitudinal axis X of the ar rangement . The shown embodiment has two extensions 7 di rected opposite directions . However, the attachment of the first part 4a may be realized some other structure, too, provided that the structure may transfer movements of the body part 1 to the first part . For instance, the extension may extend in any direction in relation to the longitudi nal axis X of the arrangement .

Second part 4b of the hydraulic actuator is attached to a support element 5. In the embodiment shown in Figures 2a - 2d, the support element 5 is attached to a frame part 12 of the mining machine by attaching means 11. Said attach ing means may comprise screws , bolts , nuts or any fixation means known per se . In an embodiment, the support element 5 is attached to a frame part 12 by a welded oint .

The hydraulic actuator 3 comprises connectors 10 for con necting said actuator to a hydraulic circuit of a braking system of the mine machine 6. The hydraulic pressure cre ated in the hydraulic actuator 3 due to the towing force affecting to the towing element 2 is arranged to release brakes of the mine machine 6. In an embodiment, the arrangement 100 comprises just one hydraulic actuator only . In this embodiment, the hydraulic actuator may be arranged e.g. inside the body part 1.

In still another embodiments , the arrangement comprises more than two, for instance three or four, hydraulic actu ators .

In an embodiment, the arrangement 100 comprises at least one returning element 8 that is arranged to return the body part 1 in its initial position in relation to the support element 5 when towing element 2 is released from the towing force . In the embodiments shown in Figures , the arrangement 100 comprises two coil spring elements as the returning element 8. In another embodiments , the returning element 8 comprises another type of mechanical spring, such as a leaf spring . In still another embodiment , the returning element 8 comprises a gas spring .

The spring elements are arranged separately from the hy draulic actuators 3. In another embodiment, the returning element 8 is integrated in the hydraulic actuator 3 , ei ther inside or outside thereof . In an embodiment, the chamber of piston rod side of the hydraulic cylinder is filled with gas , for example nitrogen . Said gas expands and its pressure drops when the cylinder is compressed . As the towing element 2 is released from the towing force , said gas in underpressurized state helps the cylinder to return in its initial length . In still another embodiment, the hydraulic cylinder comprises a spring, such as a coil spring, arranged inside the cylinder or around the exteri or of the cylinder .

In an embodiment, the arrangement 100 comprises a stopper arrangement 9 that transfers at least a part of towing forces from the body part 1 to the frame of the machine . In the embodiment shown in Figures, the stopper arrange ment 9 comprises an oblong through hole 14 in the body part 1, and a pin 13 arranged movably in the hole 14. The pin 13 is attached to the frame of the machine and ar ranged perpendicular to the moving direction M of the body part 1. The pin abuts against the hole 14 when the machine 6 is being towed. In another embodiment, the body part 1 comprises an abutting surface or extension (not shown) that abuts against a frame part of the mine machine and thus transfers towing forces in the frame of the mine ma chine .

Figure 2c is showing the arrangement 100 in its rest state, i.e. when there is no towing force affecting to the towing element 2. The hydraulic actuators 3 and the re turning elements 8 are in their extended states and the body part 1 retracted inside the structure of the mine ma chine . I f the mine machine 6, for some reason, has lost vehicle power or hydraulic fluid pressure, an automatic fail-safe braking is on and brakes of the machine prevent the machine from moving .

Figure 2d is showing the arrangement 100 when a towing force F is affecting to the towing element 2. Now the body part 1 is pulled out from the structure of the mine ma chine . The extensions 7 are pressing the hydraulic actua tors 3 that thus get shorter . As a result, hydraulic fluid flows from the hydraulic actuators 3 to the hydraulic cir cuit of the braking system of the mine machine 6 releasing brakes thereof, allowing towing the mine machine 6.

As soon as the towing force F is withdrawn, the returning elements 8 force the arrangement 100 to return in the rest state shown in Figure 2c. Following this, the brakes of the mine machine go on, and the mine machine does not move unintentionally . In an em bodiment, the brakes go on when the towing element 2 and the body part 1 have retracted completely . In another em- bodiment, the brakes go on when the towing element 2 and the body part 1 have retracted a predetermined length to wards the rest state . In other words , the brakes go on prior to the towing element 2 and the body part 1 have reached the rest state . Said predetermined length may be, e.g. 50 mm - 200 mm, for instance 80 mm, 100 mm, or 150 mm.

The invention is not limited solely to the embodiments de scribed above, but instead many variations are possible within the scope of the inventive concept defined by the claims below . Within the scope of the inventive concept the attributes of different embodiments and applications can be used in conj unction with or replace the attributes of another embodiment or application . The drawings and the related description are only intended to illustrate the idea of the invention . The invention may vary in detail within the scope of the inventive idea de fined in the following claims .

REFERENCE SYMBOLS

1 body part

2 towing element

3 hydraulic actuator

4a, b parts of hydraulic actuator

5 support element

6 mine machine

7 extension

8 returning element

9 stopper arrangement

10 connector

11 attaching means

12 frame part of mining machine 13 pin

14 through hole

15 cooler arrangement

100 towing arrangement

F towing force

M moving direction

X longitudinal axis