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Title:
SUPPORT LEG ASSEMBLY FOR VEHICLES
Document Type and Number:
WIPO Patent Application WO/1999/020505
Kind Code:
A1
Abstract:
A support leg assembly for vehicles comprises a main beam and two displaceable secondary beams (2), which carry a support leg (4) being pivotable between a vertical parking position and a turned-out active position. Between the free end (10) of the main beam and the support leg (4), a cam guide acts having an oblique cam surface (14) and a cam tracker (16) which, when the same is at a first end of the cam surface (14), allows the support leg to assume the turned-out position and which, when the same is brought to move along the cam surface, compulsorily carries out a turning-in of the support leg to the parking position. A gas spring (19) has the purpose of automatically turning out the support leg to the extended position when the cam tracker (16) releases the leg by moving to an opposite end of the cam surface.

Inventors:
Stolpe, Jens (Storgatan 64 Hudiksvall, S-824 52, SE)
Application Number:
PCT/SE1998/001627
Publication Date:
April 29, 1999
Filing Date:
September 14, 1998
Export Citation:
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Assignee:
HIAB AB (Hudiksvall, S-824 83, SE)
Stolpe, Jens (Storgatan 64 Hudiksvall, S-824 52, SE)
International Classes:
B60S9/12; B66C23/80; (IPC1-7): B60S9/02
Foreign References:
US3871685A
US4593932A
FR1592893A
US5387071A
US3901532A
US3396854A
Attorney, Agent or Firm:
Johansson, Lars (Lars Johansson Patentbyrå AB P.O. Box 68 Gävle, S-801 02, SE)
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Claims:
Claims
1. Support leg assembly for vehicles, comprising a main beam (1) extending transverse to the vehicle and two secondary beams (2), which are displaceable in relation to the main beam bet ween interior and external end positions, and each one of which is, at a free end thereof, connected to a support leg (4) via a main hinge (3), which leg is pivotable between a parking posi tion, in which the secondary beam is inserted to the inner end position thereof and the support leg extends substantially per pendicularly to the secondary beam, and an active position, in which the secondary beam is projected from the main beam and the support leg is turned out to a position in which the same forms an obtuse angle with the secondary beam, the displacement of the secondary beam in relation to the main beam being car ried out by a doubleacting hydraulic cylinder (26), or the like, builtin in the beams, c h a r a c t e r i z e d in that a cam guide (14,16) acts between a free end of the main beam and the individual support leg (4) which cam guide includes a cam surface (14) being oblique in relation to the movement di rection of the secondary beam (2), as well as a cam tracker (16) which is distanced from the main hinge (3) and which, when said cam tracker is in the area of a first end of the cam sur face, allows the support leg to assume the turnedout position thereof and which, when the same is brought to move along the cam surface to an opposite, second end compulsorily carries out a turningin of the support leg to the parking position, and that a compression spring device (19) having a moderate spring force is connected to the secondary beam (2), which spring de vice, on one hand, is compressed when the support legin con nection with the insertion thereof to the inner end position by means of the cam guide (14,16) is forced to assume the par king position thereof, and, on the other hand, guarantees the turningout of the support leg to the turnedout position when the cam tracker (16) releases the support leg by moving along the cam surface (14) from the second end to the first end the reof.
2. Support leg assembly according to claim 1, c h a r a c t e r i z e d in that the spring device consists of a gas spring (19) of the type which comprises a stiff cylinder (20) and a likewise stiff rod piston (21).
3. Support leg assembly according to claim 1 or 2, c h a r a c t e r i z e d in that the cam surface (14) is arranged at the top of a free end portion of the main beam (1) and leans obliquely downwardsoutwards in relation to the same end por tion and that the cam tracker (16) is mounted on an upper por tion of the support leg (4).
4. Support leg assembly according to claim 3, c h a r a c t e r i z e d in that the cam surface (14), at an upper end, trans forms into a horizontal running surface (15) against which the cam tracker is arranged to abut when the support leg assumes the parking position thereof, more precisely with the purpose of mechanically locking the support leg in the same position.
5. Support leg assembly according to any one of the preceding claims, c h a r a c t e r i z e d in that the cam tracker con sists of a rotatably mounted pulley (16).
6. Support leg assembly according to any one of the preceding claims, the individual secondary beam (2) at the free end the reof having a transverse body plate (11) from which two spaced apart, vertical side pieces (12) project between which the up per end portion of the support leg is inserted and between which a tenon (3) extends which forms said main hinge, c h a r a c t e r i z e d in that on a level below the main hinge (3), at least one stop element (30) is arranged to engage a cooperating hook portion (27) underneath a side piece (12) in order to stop the support leg and limit the angle to which the leg may be turned out in relation to the secondary beam.
Description:
SUPPORT LEG ASSEMBLY FOR VEHICLES Technical Field of the Invention This invention relates to a support leg assembly in- tended for vehicles of the type that comprises a main beam ex- tending transverse to the vehicle and two secondary beams, which are displaceable in relation to the main beam between in- terior and external end positions, and each one of which is, at a free end thereof, connected to a support leg via a main hinge, which leg is pivotable between a parking position, in which the secondary beam is inserted to the inner end position thereof and the support leg extends substantially perpendicu- larly to the secondary beam, and an active position, in which the secondary beam is projected from the main beam and the sup- port leg is extended to a position in which the same forms an obtuse angle with the secondary beam, the displacement of the secondary beam in relation to the main beam being carried out by a double-acting hydraulic cylinder, or the like, built-in in the beams.

In practice, the individual support leg is of a tele- scoping type, in that the same includes an upper tube part which is articulatedly connected to the secondary beam as well as a lower, more slender tube part which is inserted in the up- per tube part and projectable therefrom by means of a hydraulic cylinder built-in in the support leg. At the free end thereof, the lower tube part has a footplate, which is articulatedly connected to said tube part.

Prior Art Previously known, commercially available support leg assemblies of the above-related kind make use of locking pins in order to lock the support legs in the extended, active posi- tion. This means that an operator has to manually insert a locking pin in the appurtenant hole after first having tilted out the individual support leg; what likewise has to be made manually. In doing so, one of the hands is occupied with hol- ding the support leg turned-out and the other one with applying the locking pin. This business is risky inasmuch as injuries on, especially, the hands and the fingers thereof, but also ot-

her limbs, may easily arise as soon as the operator is in the immediate vicinity of the movable parts of the assembly, i. e. the projectable secondary beam and the tiltable support leg.

The secondary beam is projected with a rather large force by a hydraulic cylinder. Furthermore the support leg is heavy and may, therefore, cause severe injury by crushing if an accident occurs. A risk-increasing factor is that the projection and ex- tension of the two support legs in practice is desired to be carried out in the shortest possible time so that the crane of the vehicle should be able to commence work as soon as pos- sible.

Objects and Features of the Invention The present invention aims at obviating the above- mentioned inconveniences of the previously known support leg assemblies and at providing an improved assembly. Thus, a pri- mary object of the invention is to provide a support leg assem- bly which permits not only the turning-out of the individual support leg to an oblique, out-tilted position, but also lock- ing the support leg in this position without an operator at all needing to be in the vicinity of the assembly. Thus, in prac- tice, the turning-out and locking should be able to take place in an automatic way in connection with the projection of the secondary beam from the main beam. A particular object of the invention is to provide a support leg assembly in which the turning-out and locking of the support leg is begun and execu- ted in an immediate time-wise proximity to the moment in which the projection of the secondary beam from the main beam is ini- tiated. An additional object of the invention is to provide a support leg assembly, which can execute the turning-out as well as the locking of the support leg by means of structurally simple and thereby manufacturing-wise inexpensive means.

According to the invention, at least the primary ob- ject is attained by the features defined in the characterizing clause of claim 1. Preferred embodiments of the invention are furthermore defined in the dependent claims.

Brief Description of the Appende Drawings In the drawings: Fig 1 is a partly cut front view of a support leg assembly made according to the invention and having a main beam shown with dash dotted lines as well as two support legs of which the right one is shown in a vertical parking position and the left one in an extended, ac- tive supporting position, Fig 2 is an analogous, although somewhat diminished front view showing two secondary beams housed in the main beam projected to outer end positions, as well as the two support legs out-tilted and prolonged to desired position levels, Fig 3 is an enlarged, partly transparent detailed view show- ing the support leg in the vertical parking position, Fig 4 is an analogous detailed view showing a secondary beam somewhat projected from the main beam and the support leg turned-out from the secondary beam, and Fig 5 is a partial perspective view showing the upper end of the support leg in connection with the secondary beam when this is fully inserted in the main beam.

Detailed Description of a Preferred Embodiment of the Invention The support leg assembly shown in fig 1 and 2 inclu- des a main beam 1 extending transverse to an appurtenant ve- hicle and two secondary beams 2 displaceable in relation there- to between interior and external end positions. The free end of each secondary beam is, via a main hinge 3, connected to a sup- port leg in its entirety designated 4. Said support leg is of a telescoping type insofar as the same includes an upper tube part 5 (or box profile) and a lower, more slender tube part 6 (or box profile) which is displaceably arranged within the wi- der tube part. At the free end thereof, the lower tube part 6 is connected to a support 8 via a hinge 7. Displacement of the tube part 6 out of and into the tube part 5 takes place by me- ans of a double-acting hydraulic cylinder 9 (see fig 3).

The main beam 1 has, at each one of the two opposite, open ends thereof, transverse, rectangular frame parts 10 of comparatively robust sheet-metal plate, which form stop means

determining the interior end positions of the secondary beams.

At the free end of each separate secondary beam 2, there is a likewise transverse body plate 11, which is abutted and stopped against the frame part 10 when the secondary beam is inserted.

Two side pieces 12 project from the area of the vertical side edge of the body plate 11, between which side pieces the upper end portion of the support leg is inserted. A horizontal tenon forming said main hinge 3 for the support leg also extends bet- ween said side pieces.

In the parking position thereof, shown to the right in fig 1, the support leg 4 hangs down vertically from the hinge 3. In other words, the leg forms, in this state, a 90° angle with the main beam as well as the secondary beam, which are horizontally oriented. In the active, supporting state thereof, which is visualised to the left in fig 1, the support leg is turned out to a position in which the same forms an ob- tuse angle with the beams. In the given example, this angle amounts to approx. 105°. However, the angle may in practice vary, preferably within the range of 100-110°.

In this connection, it should be mentioned that sup- port leg assemblies of the kind in question are primarily in- tended to be mounted on such vehicles which include cranes or other lifting constructions which during operation require that the vehicle is stabilised laterally in relation to the ground.

In comparison with such support leg assemblies having the sup- port legs thereof permanently fixed in a 90° angle to the appurtenant secondary beams, such assemblies which include out- turnable support legs offer the advantage that the stability of the vehicle is markedly improved by the fact that the distance between the support feet 8 of the two support legs may be con- siderably increased. Furthermore, the safety against uninten- tional tipping in connection with the parking of the vehicle on an inclined ground is improved by the fact that the main hinge 3 is, with margin, located inside an imaginary vertical line through the support feet, even if the vehicle leans somewhat laterally.

As far as the support leg assembly shown in the draw- ings has been described hitherto, the same is in all essentials previously known.

The features which are characteristic for the present invention is most clearly seen in figures 3 to 5 to which ref- erence is now made.

On each one of the two free ends of the main beam 1, more precisely at the top of the frame part 10, a nose 13 is arranged which has an upwardly turned, oblique cam surface 14.

This cam surface leans obliquely downwards/outwards, i. e. it has the highest situated point thereof located closest to the frame part 10 and the lowermost situated point thereof distan- ced therefrom. At the top, the cam surface 14 transforms into a substantially horizontal, plane or concavely arched running surface 15. A cam tracker 16 in the shape of a pulley, which is rotatably mounted between two vertical walls on an angular mo- unting plate 17, co-operates with the cam surface 14. This mo- unting plate is applied on the upper end portion of the support leg 4 and accompanies this.

A hole 18 is recessed in the body plate 11 through which hole a force generator in the shape of a compression spring device extends, having the purpose of automatically tur- ning out the support leg 4 as soon as this becomes freely pivo- table in relation to the appurtenant main hinge. In the prefer- red embodiment exemplified in the drawings, this compression spring device consists of a gas spring, in its entirety design- ated 19, which, in a conventional way, includes a form stiff cylinder 20 as well as a likewise form stiff rod piston 21. The rod piston is, via a hinge 22, connected to a fastening element 23 on the inside of the support leg, while the cylinder 20 is, via a hinge 24, connected to a fastening element 25 applied within the secondary beam 2, more precisely on a bottom flange of said beam. By the compression in a gas cushion within the cylinder 20, said gas spring always strives to turn out the support leg to the out-turned, active support position.

In this connection, it should be pointed out that the projection and insertion of the individual secondary beam takes place by means of a double-acting hydraulic cylinder 26 (see fig 3), one end of which is articulatedly connected to the body plate 11 and the opposite end of which is articulatedly con- nected to a central fastener within the main beam. The force exerted by the hydraulic cylinder 26 is in practice many times

larger than the spring force of the gas spring 19. This means that the shortening of the gas spring during simultaneous com- pression of the gas cushion therewithin may be carried out wit- hout substantial resistance when the hydraulic cylinder 26 gua- rantees the insertion of the secondary beam in the main beam.

As may be most clearly seen in fig 5, a hook-shaped portion 27 defining a concavely rounded shoulder surface 28 is provided in the lower end of each individual side piece 12. A stop pin 30 is mounted between two bracket plates 29 on the in- side of the support leg 4, the opposite end portions of which stop pin protrude somewhat from the bracket plates and may be brought into engagement with the shoulder surfaces 28. In other words, the stop pin 30 together with the hook portions 27 serve as stopping means which limit the mobility of the support leg to a maximum turning-out angle (t ex 105°).

The Function and Avantages of the Invention In the parking position according to figures 3 and 5, the hydraulic cylinder 26 is shortened to a minimal length, which means that the secondary beam is fully inserted into the main beam to an inner end position in which the body plate 11 abuts against the frame part 10 (as is shown in fig 5). In this state, the gas spring 20 also has a minimal length, the gas cushion within the cylinder being maximally compressed. At the same time the pulley 16 serving as a cam tracker abuts against the upper journal 15 on the nose 13. This means that the sup- port leg 4 is locked in the position pending vertically from the secondary beam, by the fact that the pulley 16 distanced from the main hinge 3 cannot be turned in the direction down- wards.

When the support leg is to be activated, the projec- tion of the secondary beam from the main beam is started, more precisely by extending the hydraulic cylinder 26. This results in the cam tracker pulley 16 leaving the upper, stopping jour- nal 15 and starting a transfer along the oblique cam surface 14. As the pulley follows the cam surface from the highest point to the lowest, the freedom increases successively for the support leg to turn around the main hinge. Therefore, by the fact that the gas spring 19 continuously acts against the sup-

port leg, this leg will successively be turned out in the di- rection to a fully out-turned state. This state is reached when the pulley leaves the lowest point of the cam surface, as is shown in fig 4. At this stage, the stop pin 30 has reached the hook portions 27 on the side pieces 12 of the secondary beam, whereby additional out-turning of the support leg is made im- possible. The projection of the secondary beam from the main beam to the desired position, e. g. the maximally projected po- sition, continues when the extension and locking of the support leg in relation to the secondary beam have taken place. After this, the lower telescope part 6 of the support leg is pushed down by means of the hydraulic cylinder 9 until the support foot is distinctly abutted against the ground (thereafter cer- tain additional projection may also take place with the purpose of lifting the appurtenant vehicle somewhat).

When the individual support leg is to be returned to the parking position, one proceeds in the opposite way, i. e. the bottom part of the support leg is pulled up in the upper part by means of the hydraulic cylinder 9, and the insertion of the secondary beam in the main beam is started by means of the hydraulic cylinder 6. During this insertion movement, the gas spring 19 still acts against the support leg and keeps this turned-out relative to the secondary beam. When the pulley 16, at the end of the insertion movement, meets the cam surface 14 on the nose 13, the support leg is forced to turn in the direc- tion inwards to the vertical parking position thereof as the pulley rolls up along the oblique cam surface 14. Turning-in of the support leg takes place without noticeable resistance from the gas spring by the fact that the hydraulic cylinder 26 acts with a considerably larger force than the gas spring. When the pulley leaves the highest point of the cam surface 14 and is transferred to the upper journal 15, the secondary beam arrives to the inner end position thereof, in which the pulley, in the way described initially, locks the support leg in relation to the secondary beam.

A substantial advantage of the invention is that the turning-out as well as the turning-in of the support leg bet- ween the parking position and active position is automatically guaranteed, i. e. entirely without manual help. This means that

the driver of the vehicle and the crane does not at all need to be in the vicinity of the support assembly in connection with this being made ready for crane work and departure of the vehi- cle, respectively. Thus, the risk for injury in connection with the handling of the support assembly is entirely and fully eli- minated.

Feasible Modifications of the Invention The invention is not solely restricted to the embodi- ments described above and exemplified in the drawings. Thus, it is feasible to use other compression spring devices instead of gas springs in order to guarantee the extension of the support legs after releasement. Guided pressure screw springs may, for instance, be used. It is even feasible to use other force gene- rators than spring devices, e. g. diminutive hydraulic cylinders that are activated by particular control valves in the hydrau- lic system in connection with the turning-out and the turning- in, respectively, of the support leg. Furthermore, the cam guide described may be realized in another way than the one which is shown in the drawings. Thus, the oblique cam surface (which may be straight as well as curved) may be arranged on the support leg, while the pulley or the cam tracker is mounted on the main beam. Instead of a pulley, other cam trackers may also be used, e. g. sliding bodies. It may also be pointed out that the main cylinder 26 may be replaced by equivalent devices for pushing and pulling the secondary beam, e. g. a screw mecha- nism of the type which includes a threaded shaft and a rota- table nut.