The invention relates to an arrangement for a semi-trailer landing gear and the related gearbox, wherein the landing gear includes a screw hoist with a gearbox as well as its rotating device including a power input and a power input shaft for rotating the former, adapted at the same time to control the gearbox of the screw hoist according to its axial position, whereby the axial movement of the power input shaft controls the gear ratio of the screw hoist gearbox at least between two steps, and which arrangement includes an operating device for operating the power input shaft axially, and wherein the rotating device further comprises a drive motor.

The road tractor of a semi-trailer combination is a truck equipped with a trailer dolly. A semi-trailer is connected on top of the trailer dolly. The road tractor of a semi-trailer is often called a road traction engine, a semi-trailer truck, or a tractor. A semi-trailer combination is often called a semi-trailer lorry.

The weight of the front part of the trailer is supported on the trailer lorry. A semi-trailer is commonly used in transporta- tion between countries. Since these have normally standard dimensions, it is normal that the company owning the road tractor does not own the towed trailer, or this may be registered by some other country. An example of a normal procedure is that an empty trailer is loaded in Finland, only the trailer is loaded onboard, and another truck picks up the loaded trailer from the harbor in Germany.

The trailer is disconnected from the road tractor as follows: The locking of the trailer dolly located on top of the road tractor frame is disengaged. The front part of the trailer is equipped with so called landing gear legs, which are lowered down by the drived. The landing gear legs support the weight of the front part of the trailer. The legs are lowered using muscular strength. Using a crank and a gearbox, the driver lowers the legs by winding the crank.

Several different landing gear mechanisms are known. From patent publications US 4,187,733 and US 5, 538 , 225, two-speed lifting mechanisms are known which are operated in a normal way using a crank. In these mechanisms, a gear ratio change is incorporated in the axial movement of the crank, which permits performing the lifting operation either fast, using small force, or slowly, using great force. On the other hand, several motor-driven landing gears have been proposed, such as for example in patent publication US 4,097,840 or application publication US 2003/0209896 Al . Many motor-driven mechanisms are no more suitable for manual operation at all, or such operation is difficult. Motor-driven mechanisms cannot be applied in prior art in connection with said two-speed lifting mechanisms .

A known application publication US 2007/0182148 Al proposes a lifting mechanism which can be used both with a motor and manually. This solution uses special legs inside of which a complicated lifting mechanism is installed.

The object of the invention is to provide a novel compact arrangement for a semi-trailer landing gear in which a two-speed lifting mechanism can be operated either with a motor or manually.

This object can be achieved according to the invention in such a way that the operating device for changing the axial position of the power input shaft of the landing gear gearbox is an actuator integrated in the power input shaft, and the arrange- ment additionally includes control means for the operating device . The rotating device includes a frame component for rotating the power input shaft of the landing gear gearbox, the frame component being mounted with bearings axially around the power input shaft and with the actuator adapted within the frame component. The actuator is unidirectional and it has a return spring associated therewith. The grooved hollow shaft and the power input shaft of the landing gear gearbox are locked to each other with locking pins adapted inside the power input shaft. The locking pins also protect the auxiliary device against theft.

Advantageously, the actuator comprises a cylindrical piston operated with a pressure medium and an actuator cylinder, formed by the peripheral cylinder of the cylindrical piston, which is placed centrally relative to the power input shaft.

For the arrangement, a compact auxiliary device has been formed comprising a drive motor integrated in the rotating device and an actuator operated with the drive motor for changing the axial position of the power input shaft of the landing gear.

An advantageous arrangement is in connection with a landing gear of such a semi-trailer in which the front plate of the landing gear gearbox is fixed with screws to the landing gear. Thus the auxiliary device is adapted to be fastened to the front plate, which enables achieving easy installability of the auxiliary device to the landing gear as well as precise positioning relative to the power input shaft of the landing gear gearbox.

An arrangement includes an electric motor operated hydraulic power unit which is used to operate the motor and the actuator. Most advantageously, both the drive motor and the operating device are pneumatic, as compressed air is usually available from the road tractor. According to an embodiment, the arrangement includes a reduction gear, and the drive motor of the arrangement is of a type that rotates fast to two directions. The rotating device further includes a reduction gear adapted between the drive motor and the operating device for changing the torque. The reduction gear can be a worm gear, for example.

In an embodiment, the drive motor has an axially moving grooved shaft and an internal gear grooved hollow shaft that rotates the former, permitting axial movement of the grooved shaft.

In another embodiment, the operating device that controls the gearbox comprises an actuator within the grooved hollow shaft, operated with a pressure medium.

In a simplified version, the operating device is a manual lever operated by turning an extension of a grooved hollow shaft.

In an advantageous embodiment, the drive motor and the operat- ing device are separate parts of the rotating device and a reduction gear is installed between these.

Compared to prior art arrangements, an advantage of the arrangement according to the invention is its compact size and easy installability . In addition, the arrangement can also be used manually. Lifting or lowering of the landing gear takes only about 20 seconds, at the shortest. Advantageously, the auxiliary device weighs only about 20 kg. The arrangement according to the invention is suitable for use connected directly to the front plate of a landing gear gearbox of standard semi-trailers without any modifications in the leg or the equipment . Other advantageous embodiments and advantages of the invention are described below in connection with application examples. Instead of a pneumatic drive motor and operating device, it is naturally possible to use a hydraulic power unit or an electrical power unit. For a hydraulic actuator, the trailer can be equipped with a battery operated hydraulic power unit, for example, which is charged from the road tractor during driving. Hydraulic actuators can be manufactured with quite small a size .

The invention is described below by making reference to the enclosed drawings, which illustrate an embodiment of the invention, in which

Figure 1 shows the landing gear as a whole, however, with the auxiliary device partly dismounted,

Figure 2 shows the motor partly disassembled and fastened to the landing gear,

Figure 3 is a cross-sectional view of the motor of the auxiliary device with the shaft pushed out,

Figure 4 is a similar cross-sectional view as in Figure 3 with the shaft pushed in,

Figure 5 shows the auxiliary device as a whole separated from the rest,

Figure 6 is an exploded view of the auxiliary device assembly,

Figure 7 is an exploded view of the pneumatic motor assembly,

Figure 8 is a lateral view of the auxiliary device with the outer casing cut open,

Figure 9 is a top view of the auxiliary device,

Figure 10 shows the auxiliary device from the side of the power input shaft,

Figure 11 shows an advantageous design for the blade, Figure 12 shows the blade of Figure 11 in a cut state, Figure 13 is an exploded view of the second embodiment of the invention,

Figure 14 is an axonometric view of the auxiliary device W

according to the embodiment of Figure 13 without the shell,

is a lateral cross-sectional view of the auxiliary device according to the embodiment of Figure 13, shows the pneumatic connection diagram of the second embodiment of the arrangement according to the invention,

is an axonometric view of the second embodiment of the arrangement according to the invention as a whole,

is a lateral view of the second embodiment of the arrangement according to the invention as a whole, is an axonometric view of the transmission of the auxiliary device of the second embodiment of the arrangement according to the invention.

The reference numbers in the figures refer to the followinc

1 Motor cylinder 18 Piston

2 Frame component 19 Thrust bearing

20 3 Counter toothing 20 Piston return spring

4 Blade groove in frame 21 Torsion shaft

4.1 Blade half 22 Mounting iron

4.2 Blade half 23 Rear cover

6 Blade springs 24 Shell

25 7 Motor blades 25 Front cover

8 Grooved hollow shaft 26 Name plate

8' Fin 27 Control means

9 Frame bearings 28 Landing gear

10 Rear flange 29 Landing gear base

30 11 Front flange 30 Motor assembled

12 Spring flange 31 Mounting iron

13 Locking pin 32 Complete auxiliary

14 Power input shaft device assembled

15 Spring for locking pins 33 Notch

35 16 Blade spring 35 Semi-trailer frame b<

17 Cylinder 36 Slot 38 Fitting (compressed 75 Rotating device air) 77 Landing gear gear box

39 Compressed air pipe 81 Motor cylinder

40 Intermediate flange 82 Motor blades

5 41 Cotter 83 Motor shaft

44 Reduction gear 84 Front bearing of motor

45 Spring 85 Worm gear

46 Actuator 86 Roll pin

48 Operating device 87 Bearing for bearing

10 49 Space pedestal of motor

50 Drive motor supply 88 Front protection of

pressure line motor bearing

51 Control valve 89 Rear end plate of motor

52 Control valve 90 Front end plate of mo¬

15 53 Control valve tor

54 Control button 91 Motor pedestal

56 Manifold 92 Motor shaft protection

58 Valve 93 Motor bearing pedestal

62 Crank opening for man94 Valve 5/3

20 ual operation 95 0-ring

70 Front plate of landing 96 O-ring

gear gear box 97 Bearing flange

72 Screw holes in front 98 Cylindrical screw

plate 99 Sliding pin

25 74 Screws for gearbox

Figures 1 - 12 show the first embodiment of the arrangement according to the invention in which the operating device is located inside the drive motor. Figures 13 - 19 show the second embodiment in which the operating device and the drive motor 30 are located separately within the rotating device.

In Figure 1, reference number 28 represents a conventional lifting leg with a lifting mechanism located inside and in which a drive motor according to the invention is connected to a power input shaft. In the figure, the lifting leg is shown with the telescopic section retracted. At the bottom end of the telescopic part, this version has a base 29 for lowering the surface pressure. Instead of a base, steel rollers or some other support surface are also used.

In this first embodiment the drive motor 30 and the operating device located within it are fastened to a mounting rack 22, which has been bent from a sheet to a U-shape to be adapted around the landing gear. At the same time, this functions as a moment support for the drive motor. In Figure 2, the front flange 11 and the outer cylinder of the drive motor have been removed to make the rotor 2 complete with its blades 7 visible against the rear flange 10. At the center, around the grooved hollow shaft 8, the actuator 17 of the operating device of the gearbox is shown placed coaxially around the grooved hollow shaft 8. Figures 3 and 4 correspond to each other except for the power input shaft 14, controlled by the actuator 17 of the operating device, which is axially in a different position. The rotation force is supplied by a known method through the power input shaft 14 to the lifting mechanism of the landing gear. At the same time, the power input shaft also operates the lifting mechanism gear by moving it in and out in the axial direction for a selected distance. In the position of Figure 3 the shaft is out while the actuator cylinder 17 is non-pressurized and the spring 20 pushes the piston 18 inside the cylinder 17 via the thrust bearing 19. Here the thrust bearing 19 rotates relative to the piston 18, which moves only axially in a peripheral cylinder 17 that is fixedly mounted to the front bearing. The drive motor comprises as its main components a rear flange 10, a cylinder 1 and a front flange 11, with a sheet-formed rotor frame 2 complete with its blades 7 mounted between these. The blades 7 are mounted to the grooves 4, shown in Figure 2, 5 of the sheet-formed rotor frame. The sheet-formed rotor frame 2 is set rotary supported by the bearings 9 which are carried by the front and rear flanges 11 and 10. In a method known as such, the lamella blades are tensioned against the outer cylinder using springs 16. However, opposing lamella blades cannot 10 be tensioned here with one spring, because the sheet-formed rotor has a grooved hollow shaft 8. Therefore the springs 16 are placed in deep openings formed in the lamella blades and thus each spring is pressed to the bottom of the groove .

15 The sheet-formed rotor frame 2 rotates the grooved hollow shaft 8, which has axial toothing 8'. The sheet-formed frame 2 has fins or counter toothing that are suitable for this toothing permitting the grooved hollow shaft 8 to move axially. The power input shaft 14 is fastened to the grooved hollow shaft 8

20 with locking pins 13. The locking pins 13 and their spring 15 are placed inside a bore located in the power input shaft 14 of the landing gear gearbox. This bore is standardly fitted in all standard gear shafts. The opposing locking pins 13 are pressed to the notches 33 of the grooved hollow shaft 8 by the spring

25 15 located between the locking pins 13 whereby the locking pins 13 transmit a force from the grooved hollow shaft 8 to the power input shaft 14 in all conditions. As an extension to the grooved hollow shaft 8 it is possible to use an auxiliary shaft 21, which is fastened from the mounting point 41 using a cot-

30 ter. With the auxiliary shaft 21, the lifting leg can still be operated with a crank as before.

In Figure 4, pressure is applied to the cylinder 17 of the operating device through a pipe line 39 and a fitting 38, whereby the piston 18 presses the grooved hollow shaft 8 inwards through the thrust bearing 19. The spring 20 compresses simultaneously by the force of the pneumatic cylinder. The auxiliary device comprises a casing having a rear wall 23, a plate casing 24 and a front wall 25. These also carry control valves, which are described below. A mounting iron 22 is fastened to the casing by means of an intermediate flange 40 and with this mounting iron the auxiliary device is further con- nected to an existing lifting leg and, at the same time, the crank is removed from the power input shaft 14, if it has been connected thereto.

Figure 5 shows the auxiliary device as a whole. The auxiliary device, according to Figure 6, is composed of a few main parts, which are: support casing 22, rear wall 23, casing component 24, drive motor 30, front wall 25, valve assembly for control means 27, name plate 26, and auxiliary shaft 21. The main parts of the drive motor, according to Figure 7, are: rear flange 10, outer cylinder 1, drive bearings 9, grooved hollow shaft 8, sheet-formed rotor 2, spring 20, spring flange 12, thrust bearing 19, cylindrical piston 18, cylinder 17, and front flange 11.

In Figure 9, the auxiliary device is seen from above, in which case it is easy to contemplate placing a landing gear cross-section inside the support casing 22. According to Figure 10, the grooved hollow shaft 8 is ready to receive said power input shaft 14. The auxiliary device is suitable for use directly in connection with standard semi-trailer landing gears without any changes in the leg or the equipment. The auxiliary device can be connected to the bolts or screws of the landing gear gearbox whereby the alignment of the power input shaft of the landing gear gearbox, relative to the grooved hollow shaft 8 of the auxiliary device, is accurate and the auxiliary device functions correctly. For non-standard landing gears, the mounting iron can be formed suitable for each case.

5

According to Figure 8, the valve assembly is installed on the support iron 31 at the bottom of the casing 24 below the drive motor 30. Pressure medium connections between the valve assembly and the drive motor are not shown.

10

Ά simplified modification can be made from the above example according to the figures by changing the operating device manual in which case the cylinder 17 and the piston 18 would be removed or at least inoperable. Advantageously, both axial 15 positions of the shaft include holding means, for example a spring suspended ball that holds the axial bearing axially in place (not shown) . A knob (not shown) can be used at the end of the shaft 21 for facilitating manual operation.

20 Efficient sealing of the blade against the ends and the outer cylinder can be advantageously achieved with the blade application of Figures 11 and 12. The blade 4 consists of two parts 4.1 and 4.2, which are tied together in such a way that they can slide against each other in the cutting plane. The spring

25 45 located inside presses the parts to different directions, i.e. against the ends. The radial springs are similar as shown in Figures 3 and 4.

Next, the second embodiment of the arrangement according to the 30 invention is described in which the drive motor and the operating device are separate parts of the auxiliary device.

Figure 13 shows an exploded view of the second embodiment the invention in which the operating device 48 of the auxili device 32 as well as the drive motor 30 are placed separately inside the auxiliary device 32. In addition, between the drive motor 30 and the power input shaft 14 of the landing gear 28 gearbox, there is advantageously a reduction gear 44. A sheet-formed rotor which receives its driving force from compressed air can be used as the drive motor. The operating range of a sheet-formed rotor is within high speeds of rotation, for the operating speed of a sheet-formed rotor can be 4000 - 10000 rpm. With a direct connection, lowering of the landing gear takes place too fast due to which a reduction gear 44 is installed between the drive motor 30 and the operating device 48. In the embodiment shown in Figure 13, a cylindrical screw 85 rotates a worm gear 98. The worm gear 98 is fastened to the frame 2 of the operating device 48 such that the drive motor 30 rotates the frame 2 of the operating device. Advantageously, the reduction gear 44 is a worm gear with the gear ratio ranging between 1/20 and 1/200, being advantageously about 1/60. The advantage of a worm gear is its low investment cost and high gear ratio. Other gear types can also be used as the reduction gear.

The drive motor of the auxiliary device should advantageously be of a type that rotates to two directions in order that the landing gear can be lifted and lowered in a controlled way. The drive motor used in the second embodiment of the invention is a sheet-formed rotor of the type that rotates fast to two directions, removing air from the center. Compressed air can be supplied to the sheet-formed rotor from two different directions according to which of the two operations is concerned: lifting or lowering of the landing gear. Compressed air can be removed, for example, through exhaust openings placed symmetrically relative to the supply openings. An advantage of a pneumatic sheet-formed rotor is good torque when starting the drive motor. In addition, compressed air is easily available in a semi-trailer .

The auxiliary device is locked to the front plate 79 of Figure 13 of the gearbox 77 of the landing gear 28 with screws 74, which ensures that the alignment of the auxiliary device is successful. With the screws 74 of the front plate 70 of the gearbox 77, the power input shaft 14 of the landing gear 28 gearbox 77 can be accurately positioned relative to the auxiliary device, which would be otherwise difficult to achieve. Generally the front plate of the gearbox is of a standard size, which facilitates installation of the auxiliary device. Mounting irons can be manufactured suitable for each application or they can be formed from a mounting iron that is suitable for a standard landing gear. Mounting of the auxiliary device to the landing gear is shown in Figures 17 and 18 as well.

Figure 14 shows an axonometric view of the auxiliary device 32 according to the embodiment of Figure 13 without an outer shell. For controlling the arrangement according to the inven- tion, the auxiliary device 32 can have a 5/3 valve 94, which is used to transfer operator commands to the drive motor 30 and the operating device 48. Pressure lines (not shown) for conveying the pressure depart from the valve 94 to the drive motor 30 and the operating device 48. At the end of the grooved hollow shaft 8, there is a slot 36 for the manual operation crank to which slot the crank is attached.

Figure 15 shows a lateral cross-sectional view of the rotating device 75 of the embodiment of Figure 13. A worm gear 98, fastened to the frame 2, is used to transmit the force coming from the reduction gear 44 first to the frame 2 and further to the grooved hollow shaft 8 via the slide pins 99. The worm gear 98, the frame 2 as well as the slide pins 99 are shown in more detail as a separate element in Figure 19. From the grooved hollow shaft 8 the force is transmitted to the power input shaft 14 of the landing gear gearbox by means of locking pins 13. The locking pins function in a similar way as in connection with the first embodiment. The frame 2 can be manufactured from aluminum, for example, and its construction can be relieved as shown in Figure 19. The slide pins can be manufactured from plastic,, for example, for reducing sliding friction, and they are fixedly connected to the frame 2. The design of the slide pins can be semi-circular, for example, in which case corre- sponding profiles are made in the grooved hollow shaft 8, which together enable the force transmission from the slide elements to the grooved hollow shaft 8. Due to the slide pins 99, the grooved hollow shaft 8 can move axially during the axial movement and, at the same time, it is capable of transmitting the rotating motion coming from the drive motor to the power input shaft of the landing gear gearbox.

Compared to the first embodiment of Figures 3 and 4, the auxiliary device of the second embodiment of Figure 15 lacks all that is related to the drive motor located inside the protective shell 1, i.e. motor blades, blade springs and blade grooves in the frame. These are replaced by a worm gear 98 and an empty space 49, for example. Otherwise the structure corresponds to the embodiment of Figures 3 and 4. With the arrange- ment of the embodiment of Figures 13 and 15 in which the drive motor and the operating device are separate, easy serviceability of the auxiliary device is achieved. For example, servicing the drive motor is notably easier when it is within the shell of the auxiliary device as a separate part which can be easily removed for servicing.

The piston 18 of the actuator 46 can be manufactured from plastic by injection molding, for example. As regards the injection molding technique, the piston can be manufactured in two parts in which case manufacturing of the groove required by the sealing ring does not create a problem. The piston can also be relieved by leaving an empty space inside the outer shells.

5 Figure 16 shows the hydraulic diagram of the auxiliary device of the second embodiment of the arrangement according to the invention. Compressed air is led to the auxiliary device via the valve 58 from the compressed air system of the semi-trailer. Compressed air is led to a manifold 56 which

10 divides the flow into four parts, to three control buttons and the major part of the flow to the supply line 50 of the drive motor 30. The control buttons are illustrated in Figure 17. The flows for the control buttons are led to the control valves 51 - 53 of the control buttons, of which the control valves 51 and

15 52 control the up and down movement of the landing gear while the control valve 53 controls the axial movement of the actuator 46. Actuation of the control buttons shifts the position of the control valves 51 - 53 so that compressed air can flow forward. The control buttons are of a spring-return type.

20 Compressed air coming from the control valves 51 and 52 controls the position of the 5/3 valve 94 according to which the drive motor 30 rotates by means of the supply line pressure. The valve 94 has three positions according to which it controls the operation of the drive motor 30.

25

According to an embodiment, electric control can also be arranged for the control valves in which case the operator can perform lifting and lowering of the landing gear from the vehicle. In such an arrangement, the control valves are supple- 30 mented with a solenoid which is responsible for the valve movement .

The arrangement according to the invention for a semi-trailer landing gear is shown as a whole in Figures 17 and 18. Figure 18 additionally depicts the mounting of the landing gear 28 to the semi-trailer frame beam 35. The auxiliary device 32 is mounted to the landing gear 28 using a mounting iron 22 in such a way that the mounting point of the auxiliary device 32 can be aligned with the landing gear 28 gearbox. When the landing gear 28 is connected to the semi-trailer frame beam 35, the landing gear legs 28 are sufficiently far from each other and the auxiliary device 32 is at the edge of the semi-trailer, which is a useful position for the operator. Based on Figures 17 and 18, the compact size of the arrangement according to the invention is easily detectable.

The operator controls the auxiliary device 32 using the control means 27 via mechanical control valves and compressed air. The control valves are operated by pressing the control buttons 54. With the control buttons 54, the operator can control the up and down movements of the landing gear as well as change the gear. In problem situations, the operator can connect a crank to the slot at the end of the grooved hollow shaft 8 through a crank opening 62 located in the front plate 25, for manual operation. With the crank, the auxiliary device can be operated either completely manually or just in order to help the drive motor in situations when the drive motor is not capable of moving the landing gear legs alone. For completely manual operation, the mounting of the reduction gear can also be removed.