Technical field

The invention relates to a method of partially lifting a vehicle with active sus pension to raise at least one tire of the vehicle from the ground as defined in claim 1 . The invention also concerns a support leg and use of the support leg for partially lifting a vehicle with active suspension in accordance with other independent claims.

Background

To perform various types of maintenance tasks on a vehicle, such as replacing a tire, a vehicle, including its tires, needs to be lifted above the ground during the maintenance.

A common way to lift a vehicle is by using a mechanical rotating screw jack, such as a house or a scissor jack. A rotating screw jack is operated by turning a crank inserted into one end of the jack. When the crank is turned, the screw turns, transferring the rotational motion into a linear vertical motion and raising the jack.

Another common way to lift a vehicle is by using a hydraulic jack, such as a floor or a bottle jack. A hydraulic jack is operated by moving a pump plunger to create a pressure through a hydraulic liquid to a lifting cylinder, thus raising the cylinder and the vehicle. Hydraulic jack can magnify the applied force, thus reducing the exerted work compared to a mechanical jack.

A problem associated with known lifting jacks is that either manual labour or a power supply and a motor is required for performing the work. Some jacks may be plugged into the 12 V power supply of the vehicle, thus removing the need for an additional external or integrated power supply for the jack. However, the 12 V powered jack still comprises a motor for converting electrical power into mechanical power. Manual operation of a jack can be time consuming and inefficient, whereas motor powered jacks are more complex, resulting in higher cost, weight, size and increased number of parts that might need maintenance. A further problem associated with known lifting jacks, in particular with the hy draulic bottle jacks, is a low, non-adjustable height of the bottle jack as well as a limited lifting range due to which the bottle jack is typically raised from the ground by placing it on a brick or other flat surface, which increases the risk of buckling.

Summary

An object of the present invention is to provide an alternative and improved method of partially lifting a vehicle with active suspension to raise at least one tire of the vehicle from the ground. The characterizing features of the method according to the invention are given in claim 1 . Another object of the invention is to provide an improved support leg and a use of the improved support leg for lifting a vehicle with active suspension. The characterizing features of the support leg and the use of the support leg according to the invention are given in the other independent claims.

The method according to the invention for lifting a vehicle with active suspen sion uses a support leg with a height adjustable body and utilizes the vehicle’s active suspension adjustable between a low position and a high position, where the distance between the vehicle’s chassis and an axle is smaller in the low position than in the high position, where said method comprises:

- a compression step, in which the vehicle’s air suspension is adjusted to a low position by compressing an at least one air spring resulting in an increased distance between the ground and the bottom surface of the air spring, said air spring having a top side attached to the chassis and a bottom side attached to a lever rotatable around the axle,

- a positioning step, in which the support leg is positioned under the air spring,

- a height adjustment and locking step, in which height of the support leg is first adjusted and then locked to match the distance between the ground and the lever under the air spring as closely as possible, and

- an expansion step, in which the vehicle’s air suspension is adjusted to a high position by expanding the at least one air spring, thus forcing the vehicle’s axle, tire and chassis to rise. The support leg according to the invention for use in the method for lifting a vehicle defined above comprises:

- a height adjustable body comprising at least two parts that are movable with respect to each other along a central axis, where said central axis is perpendicular to the ground when the support leg is in use, and

- a mounting head attached to the top of the body and rotatable around an axis perpendicular to the central axis.

The current invention further discloses the use of the support leg defined above for lifting a vehicle by utilizing the vehicle’s active suspension.

With the method and the support leg according to the invention, a vehicle can be lifted by utilizing the vehicle’s active suspension and the geometry of the axle, where the support leg assists the lifting process by countering the down ward force from the active suspension system. The expression “lifting a vehi cle” refers here to partial lifting of the vehicle, where one of the tires can be raised from the ground to allow service work, in particular changing of a tire. Utilization of the vehicle’s active suspension provides the work needed to lift the vehicle, without needing to exert manual labour or use any additional power supplies or motors other than the vehicle itself. The method according to the invention speeds up maintenance tasks, such as change of a tire. The method and the support leg according to the invention further make the maintenance work safer, removing the risk of jack buckling.

The method according to the invention enables lifting of a vehicle without the conventional lifting jacks, instead replacing the jack by a simpler, lighter and cheaper support leg, which is easy to transport, takes less space and is more durable.

The support leg according to the invention provides a versatile tool that can also be used in circumstances where a weight needs to be supported at a certain height. The support leg can, for example, be used for supporting a tow ing bar or a trailer once it is disconnected from the towing vehicle.

According to an embodiment of the invention, the positioning step further com prises an adjustment of a mounting head, which is attached to the top of the body of the support leg and is rotatable around a horizontal axis, parallel to the ground when the support leg is in use, said adjustment comprising rotating the mounting head until the top surface of the mounting head is parallel to the bottom surface of the lever under the air spring and the body of the support leg is perpendicular to the ground. This ensures a stable and secure positioning of the support leg, where the contact surface between the support leg and the lever is maximized and the support leg is perpendicular to the ground, maxim izing the load that the support leg can support.

According to an embodiment of the invention, the positioning step further com prises aligning a hole in a mounting head of the support leg with a mounting bolt protruding from the bottom surface of the lever under the air spring to pre vent lateral movement between the support leg and the vehicle. This increases the safety as the support leg is restricted to a fixed position, preventing it from sliding out laterally during maintenance of the vehicle.

According to an embodiment of the invention, the positioning step further com prises using a magnet located in a mounting head of the support leg to attach the support leg to the bottom surface of the lever under the air spring. Attaching the support leg with the help of a magnet enables quicker, more accurate and more secure alignment of the support leg. In particular, when the positioning step comprises aligning a hole in the mounting head with a mounting bolt, alignment can be time consuming. A magnet can help to automatically align a hole with a mounting bolt. Use of a magnet in the positioning step further sim plifies adjustment of the mounting head, since the mounting head and the sup port leg automatically move into the correct position when the support leg is attached to the air spring with a magnet.

According to an embodiment of the invention, the method comprises a step of attaching an upper end of the support leg to a fixing element that is attached to the vehicle or directly to an element forming part of the suspension of the vehicle. The support leg could thus be attached to a specific fixing element that has been attached to the vehicle. Alternatively, the support leg could be at tached directly to the vehicle.

According to an embodiment of the invention, the upper end of the support leg is attached to said fixing element or to said element forming part of the suspension by means of at least one bolt, locking pin or similar element. This ensures reliable attachment.

According to an embodiment of the invention, the height adjustment and lock ing step comprises:

- moving at least two parts of the height adjustable body of the support leg relative to each other until a height is found such that a pair of holes on the at least two parts of the height adjustable body align and the support leg height is closest to the distance between the ground and the lever under the air spring, and

- locking the height selection by inserting a locking pin through the aligned holes.

The height adjustment and locking step enables the support leg to be used with various vehicles where the distance from the ground to the air spring is different. The height adjustment enables to match the support leg’s length as closely as possible to the distance from the ground to the vehicle, thus increas ing the height to which the vehicle can be raised. The height adjustment further removes the need for additional props, such as a brick or other flat surface, that are commonly used together with a bottle jack, thus also removing the risk of bottle jack buckling.

According to an embodiment of the invention, the mounting head of the support leg further comprises a magnet for quick attachment of the support leg to the vehicle. The magnet further increases the versatility and ease of use of the support leg, resulting in a more secure and quicker attachment of the support leg to the part of the vehicle that needs to be supported.

According to an embodiment of the invention, the mounting head of the support leg further comprises at least one hole for receiving a mounting bolt, protruding from a lever to which an air spring of an air suspension of the vehicle is at tached, for preventing lateral movement between the support leg and the ve hicle when the support leg is in use and the vehicle is lifted.

According to an alternative way of implementing the invention, the support leg comprises a height adjustable body comprising at least two parts that are mov able with respect to each other along a central axis, where said central axis is perpendicular to the ground when the support leg is in use, wherein one end of the support leg is configured to be attached to a fixing element that is at tached to the vehicle or directly to an element forming part of the suspension of the vehicle.

No mounting head is thus needed, but the support leg can be attached directly to a part of the suspension or to a specific fixing element.

According to an embodiment of the invention, the support leg comprises at least one hole that is configured to be used for attaching the end of the support leg to the fixing element or to the suspension of the vehicle by means of at least one bolt, locking pin or similar element. The holes ensure reliable attach ment.

According to an embodiment of the invention, one of the parts of the height adjustable body comprises a plurality of holes and another part comprises at least one hole such that when the at least two parts are moved relative to each other, the holes can be aligned at a plurality of different heights, the support leg is further provided with a locking pin, where the locking pin can be inserted through the aligned holes to lock a selected height of the support leg.

Brief description of the drawings

Embodiments of the invention are described below in more detail with refer ence to the accompanying drawings, in which

Fig. 1 shows as a flowchart the method according to the invention,

Fig. 2 shows a side view of a part of a vehicle for three time moments of a method according to an embodiment of the invention,

Fig. 3 shows two perspective views of a support leg according to an embodi ment of the invention,

Figs. 4A-4C show different views of a support leg according to another em bodiment of the invention, and Figs. 5A and 5B show different views of a support leg according to still another embodiment of the invention.

Detailed description

A flowchart in figure 1 illustrates steps of the method according to the invention, comprising a suspension compression step 101 , a support leg positioning step 102, a support leg height adjustment and locking step 103 and a suspension expansion step 104.

Figure 2 illustrates the method of lifting a vehicle according to an embodiment of the invention via a sequence of three figures illustrating a sideview of a por tion of a vehicle before the compression step 101 in figure 2A, after the com pression 101 , positioning 102 and height adjustment and locking 103 steps in figure 2B, and after the expansion step 104 in figure 2C.

According to the embodiment of figure 2, the vehicle to be lifted by the method comprises an air suspension system with an air spring 201 attached between the chassis 206 of the vehicle and a lever 203. The lever 203 comprises a first arm 203a, a fulcrum 203b and a second arm 203c. The fulcrum 203b allows the lever 203 to rotate around an axle 204. The second arm 203c of the lever 203 is attached to the bottom surface of the air spring 201 . The first arm 203a of the lever 203 is attached to the chassis 206. In regular operation, the vehicle has its tires 205 on the ground 202 with a distance between the chassis 206 and the axle 204 controlled by the active suspension. The active suspension can be adjusted to a high position by expanding the air spring 201 , which moves the bottom surface of the air spring 201 as well as the second arm 203c of the lever 203 down, simultaneously moving the first arm 203a of the lever 203 up, raising the vehicle’s chassis 206 up and increasing the distance be tween the chassis 206 and the axle 204. Suspension can be adjusted to a low position by compressing the air spring 201 , which pulls the bottom surface of the air spring 201 up and allows the chassis 206 to move down.

According to the embodiment of figure 2, the method of lifting a vehicle with active suspension uses a support leg 300 with a height adjustable body 301 and utilizes the geometry of the axle 204 comprising the lever 203 rotatable around the axle 204 and attached to the vehicle’s chassis 206 at the first arm 203a and to the air spring 201 at the second arm 203c, further utilizing the active suspension of the vehicle adjustable between a low position and a high position, where the distance between the vehicle’s chassis 206 and the axle 204 is smaller in the low position than in the high position. The first step of the method, the compression step 101 , comprises adjusting the vehicle’s air sus pension to a low position by compressing an at least one air spring 201 result ing in an increased distance between the ground 202 and the bottom surface of the air spring 201 . Compression of the air spring 201 simultaneously lowers the chassis 206 and raises the second arm 203c of the lever 203 along with the bottom surface of the air spring 201. Since the bottom surface of the air spring 201 is connected to the second arm 203c of the lever 203, the first arm 203a of the lever 203 and thus the chassis 206 attached to the first arm 203a of the lever 203 moves down when the second arm 203c of the lever 203 moves up. Compression of the air spring 201 results in an increased distance between the ground 202 and the bottom surface of the air spring 201 . The air spring 201 could be compressed maximally or to a lesser extent sufficient to raise the tire 205 off the ground 202 in the following steps of the method.

During the second step of the method, the positioning step 102, a support leg 300 is positioned under the air spring 201 as shown in figure 2B.

According to an embodiment of the invention, the positioning step 102 further comprises adjusting a mounting head 302, which is attached to the top of the body 301 of the support leg 300 and is rotatable around a horizontal axis, par allel to the ground 202 when the support leg 300 is in use. During the position ing step 102, the mounting head 302 is rotated until the top surface of the mounting head 302 is parallel to the bottom surface 203d of the lever 203 un der the air spring 201 and the body 301 of the support leg 300 is perpendicular to the ground 202 as shown in figure 2B.

According to an embodiment of the invention, the positioning step 102 could be simplified by using a magnet 303 located in a mounting head 302 of the support leg 300. The support leg 300 could then be quickly attached with a magnet 303 to the air spring 201 .

For increased safety, according to a further embodiment of the invention, a mounting head 302 of the support leg 300 may comprise a hole 304 for a mounting bolt protruding from the bottom surface 203d of the lever 203 under the air spring 201 . In such case, the positioning step requires careful alignment of the hole 304 and the mounting bolt for preventing lateral movement between the support leg 300 and the vehicle. The mounting bolt could be a bolt that is used to attach the air spring 201 to the lever 203. Preferably, more than one hole 304 is provided for one or more mounting bolts of the air spring 201 .

In the third step of the method 103 according to the invention, the height of the support leg 300 is adjusted to match the distance between the ground 202 and the lever 203 under the air spring 201 as closely as possible as shown in the embodiment of figure 2B, and locking the support leg’s 300 height. According to an embodiment of the invention, the height is adjusted by moving two parts 305, 306 of a height adjustable body 301 of the support leg 300 with respect to each other until a height is found such that a pair of holes 307, 308 on the two parts 305, 306 of the height adjustable body 301 align and the support leg 300 height is closest to the distance between the ground 202 and the lever 203 under the air spring 201 . If the height locking is not continuous, as in the current embodiment comprising holes, the height could be first adjusted to match the distance between the ground 202 and the lever 203 under the air spring 201 and then reduced until a locking position is reached. Height can then be locked by inserting a locking pin 309 through the aligned holes 307, 308. The height adjustable body 301 may, however, comprise three or more parts and be pro vided with two or more locking pins with the height adjustment and locking performed in a similar manner as described above.

In the last step of the method, the expansion step 104, the vehicle’s suspen sion is adjusted to a high position by expanding the air spring 201 , thus utilizing the geometry of the axle 204 and forcing the vehicle’s axle 204, tire 205 and chassis 206 to rise as shown in the embodiment of figure 2C. When the air spring 201 expands, an upward force is exerted to the chassis 206 above the air spring 201 , a downward force is exerted onto the second arm 203c of the lever 203, which is supported by the support leg 300 preventing the downward motion of the air spring 201 and resulting in the lifting of the chassis 206, the axle 204 and the tire 205 above their starting height of figure 2A and above the ground 202. According to the embodiment where the support leg 300 com prises a rotatable mounting head 302, the mounting head rotates during the expansion of the air spring 201 , keeping the mounting head 302 top surface parallel to the bottom surface 203d of the lever 203 under the air spring 201 throughout the expansion.

According to the invention, the support leg 300 for use in the above described method of lifting a vehicle comprises a height adjustable body 301 comprising two parts 305, 306 that are movable with respect to each other along a central axis, where said central axis is perpendicular to the ground 202 when the sup port leg 300 is in use. The height adjustable body 301 could comprise three or more parts 305, 306 that are movable with respect to each other along the central axis. The support leg 300 further comprises a mounting head 302 at tached to the top of the body 301 and rotatable around an axis perpendicular to the central axis.

According to an embodiment of the invention, height of the height adjustable body 301 is adjustable from the shortest configuration to at least 1 .5 times the height of the shortest configuration. Height of the height adjustable body 301 could be 25-35 cm when adjusted to the shortest configuration and 40-60 cm when adjusted to the tallest configuration. Preferably, height of the height ad justable body 301 is adjustable from at most 30 cm in the shortest configuration to at least 50 cm in the tallest configuration.

Figure 3 shows an embodiment of the support leg 300 for use in the above described method for lifting a vehicle. According to the embodiment of figure 3, the mounting head 302 can be attached to the top of the body 301 with a hinge 310. When the support leg 300 is in use, the mounting head 302 is ro tatable around a horizontal axis, parallel to the ground 202. Preferably, when in use, the mounting head 302 is rotatable around an axis parallel to the axle 204. According to a further embodiment, the mounting head 302 is also rotat able around an axis perpendicular to the axle 204.

According to an embodiment of the invention, the central axis extends along the longest dimension of the support leg 300.

The body 301 of the support leg 300 could have a cross section, such as rec tangular, square, circular, triangular or other, where the cross section is in the plane perpendicular to the central axis of the support leg 300. Preferably, the mounting head 302 of the support leg 300 has a larger cross section than the body 301 of the support leg 300. The cross section of the mounting head 302 can be of any shape, such as circular, rectangular, trian gular or other. Preferably the cross section of the mounting head 302 is rec tangular.

According to an embodiment of the invention, the support leg 300 further com prises a base 311 at the bottom of the support leg’s body 301 . The outer pe rimeter of the base 311 is preferably larger than the outer perimeter of the cross section of the body 301 of the support leg 300. The cross section of the base 311 could be of any shape, such as rectangular, circular, triangular or other.

The support leg 300 is made of a durable, high strength material such as steel, an alloy of steel, such as stainless steel, titanium or an alloy of titanium, alu minium or an alloy of aluminium. Preferably, the support leg 300 is made of a steel alloy.

At least one of the parts 306 of the support leg’s 300 body 301 is hollow. The at least one other part 305 may be hollow or solid.

As shown in figure 3, the mounting head 302 further comprises a recess for receiving a magnet 303. Preferably, the recess comprises a magnet 303 for quick attachment of the support leg 300 to the vehicle. The mounting head 302 can comprise more than one magnet 303. The mounting head 302 can be attached to a metal bottom of an object to be supported by the help of the magnets 303. The metal bottom could be the bottom 203d of the lever 203 under the air spring 201 . The metal bottom could further be the bottom surface of a towing bar or a trailer. The metal bottom 203d could be made of a steel alloy. The bottom of the lever 203 under the air spring 201 could contain metal areas corresponding to where the magnets 303 should be attached, thus aid ing the quick alignment process.

According to an embodiment of the invention, during the positioning step 102 of the method, the support leg 300 is attached to the bottom surface 203d of the lever 203 under the air spring 201 with the aid of a magnet 303. If the support leg 300 comprises a rotatable mounting head 302, using magnet 303 attachment automatically aligns the surface of the mounting head 302 to the bottom surface 203d of the lever 203 under the air spring 201 and the height of the support leg 300 can then be adjusted by extending the support leg 300 downwards.

According to an embodiment of the invention, the mounting head 302 further comprises a hole 304 for receiving a mounting bolt protruding from the bottom surface 203d of the lever 203 under the air spring 201 for preventing lateral movement between the support leg 300 and the vehicle when the support leg 300 is in use and the vehicle is lifted. The mounting bolt could be a bolt that is used to attach the air spring 201 to the lever 203. Preferably, the mounting head comprises more than one hole 304 for receiving one or more mounting bolts. The number of holes 304 in the mounting head 302 can be equal or more than the number of mounting bolts.

According to an embodiment of the invention illustrated in figure 3, one of the parts 305 of the height adjustable body 301 comprises a plurality of holes 307 and the other part 306 comprises at least one hole 308 such that when the two parts 305, 306 are moved relative to each other, the holes 307, 308 can be aligned at a plurality of different heights. According to the embodiment, the support leg 300 is further provided with a locking pin 309, where the locking pin 309 can be inserted through the aligned holes 307, 308 to lock a selected height of the support leg 300. Figure 3A shows the locking pin 309 in a locked position and figure 3B shows the locking pin 309 in an unlocked position. Ac cording to a further embodiment, the locking pin 309 and the holes 307, 308 could comprise threads so that the locking pin 309 can be screwed in through the aligned holes 307. In this embodiment, the cross section of the body 301 of the support leg 300 can be of any shape. Preferably, the cross section is rectangular. The height adjustable body 301 could comprise three movable parts 305, 306 where the height adjustment and locking mechanism is ar ranged similarly as above and the height adjustable body 301 is provided with two locking pins 309.

According to another embodiment of the invention, the two parts of the height adjustable body 301 contain screw threads such that when one of the parts is rotated, the height of the height adjustable body 301 can be increased or de creased depending on the direction of the rotation. The locking is automatically achieved as long as no rotational motion is exerted onto the support leg 300. In this embodiment, the cross section of the body 301 of the support leg 300 is circular.

Figures 4A, 4B and 4C show from different directions a support leg 300 ac cording to an alternative embodiment of the invention. In the embodiment of figures 4A-4C, the support leg 300 does not comprise a rotatable mounting head. Instead, one end of the support leg 300, i.e. the upper end of the support leg 300, is configured to be attached to a fixing element 313 of the vehicle. The fixing element 313 is arranged below the air spring 201 . A similar fixing element 313 can be arranged below each air spring 201 of the vehicle.

In the embodiment of figures 4A-4C, the upper end of the support leg 300 is provided with holes 317. Also the fixing element 313 comprises holes 314. When the vehicle’s air suspension is adjusted to the low position, the holes 317, 314 of the support leg 300 and the fixing element 313 are aligned, and a locking pin, bolt or a similar element is used for attaching the support leg 300 to the fixing element 313. The support leg 300 can then be used in a similar way as the support leg 300 with the mounting head 302.

Preferably, the locking pin or other element allows the support leg 300 to rotate relative to the fixing element 313, which ensures that the support leg 300 re mains in an upright position as the vehicle is lifted.

The advantage of the embodiment of figures 4A-4C is that the support leg 300 is reliably attached to the vehicle.

In the embodiment of figures 4A-4C, the fixing element 313 is attached to a plate 312, which is attached below the air spring 201 by means of a bolt 315 that attaches the air spring 201 to the vehicle. However, the fixing element 313 could have a different shape and/or it could be attached to the vehicle in many alternative ways. Also, the fixing element 313 does not need to be located directly below the air spring 201 , but it could be offset in the horizontal plane.

The height adjustment of the support leg 300 of figures 4A-4C functions in the same way as in the embodiments of other figures. In the embodiment of figures 5A and 5B, the support leg 300 is similar to the support element of figures 4A-4C. In the embodiment of figures 5A and 5B, a flange 316 below the air spring 201 functions as a fixing element of the vehicle. The flange 316 is provided with a hole, and the support leg 300 is attached to the flange 316 by means of a bolt 318. Instead of the bolt, also a locking pin or a similar element could be used for attaching the support leg 300 to the vehicle.

In the embodiment of figures 5A and 5B, the support leg 300 is thus attached directly to a part that forms part of the suspension of the vehicle.

According to the invention, the support leg 300 is used for assisting the lifting of a vehicle when the vehicle’s active suspension is used. The support leg 300 could be used by placing it under the air spring 201 of an air suspension of a vehicle according to the method described earlier.

According to an embodiment of the invention, the support leg 300 could be placed below a vehicle to support its weight, e.g., after the vehicle has been lifted by other means, such as by traditional lifting jacks.

According to an embodiment of the invention, the support leg 300 could be placed below a towing bar or a trailer to support the trailer when it is discon nected from the towing vehicle.

The method, the support leg 300 and the use of the support leg 300 according to the invention is suitable for lifting a heavy vehicle having an active suspen sion and an axle configuration allowing lifting by the method. A heavy vehicle is a vehicle with a total weight, including the vehicle and the load, above 3,500 kg. In particular, the heavy vehicle could be a freight truck, a trailer, a bus, or a special purpose vehicle such as a crane truck and a fire truck.

The suspension could be any active suspension, such as hydraulic or hydro pneumatic and the spring could be any corresponding spring that can be ac tively controlled, such as a pressurized air spring 201 , a hydraulic piston or other.

The support leg 300 could be placed under the active spring 201 , or alterna tively anywhere under the chassis 206 of the vehicle if the vehicle has an active suspension system that can perform work to pull the axle 204 and the tire 205 up.

It will be appreciated by a person skilled in the art that the invention is not limited to the embodiments described above, but may vary within the scope of the appended claims.