TRAILER LANDING GEAR HAVING FORCE MEASURING ELEMENTS - Patent application

Abstract

The present invention relates to a landing gear with a force measuring element (10). The landing gear comprises an outer tube (20), an inner tube (30) movably mounted in the outer tube (20) and a transmission assembly (40) with at least one spindle (42) driven by a gear (41). The spindle (42) is fed through a spindle opening (24) in a spindle bearing plate (21) in contact with the outer tube (20) and a spindle nut (31) fastened to the inner tube (30) is held on the spindle. The present invention addresses the problem of providing a landing gear that allows a quantitative and reproducible measurement of the forces transmitted from the landing gear to the ground. This problem is solved in that the force measuring element (10) is mounted on a support component (15, 21) arranged in the force flow between the spindle (42) and the outer tube (20).

Description

[Technical field]

[0001] The invention relates to a landing gear having a force measuring element according to the features in the preamble of claim 1. [Background technology]

[0002] Such landing gear is often commonly attached to semi-trailers or trailers to support them on the ground, especially when they are uncoupled from the towing vehicle. As a result, the semi-trailer maintains a stable position in its parked position and can be approached by the towing vehicle to be recoupled. In other applications, landing gear is placed at the rear of the silo vehicle and extended to stabilize the vehicle before the tilting process is started.

[0003] From DE 10 2005 036 139 A1, a landing gear is known with a pressure element and a supporting load indicator, which indicates to the operator a safe position when extending the extension gear. The pressure element comprises a spring element and a switching element interacting therewith in the form of a mechanical button, the spring element being arranged between a spindle retaining ring arranged in a stationary manner on the spindle and a spindle bearing plate. When the landing gear is extended, the spindle moves relative to the spindle bearing plate if the surface is stable, so that the spring element is deformed and the switching element is activated. The switching element is then connected to a display element which indicates to the operator the presence of a loaded landing gear. However, it has been found to be disadvantageous that the spring element does not provide reproducible values ​​after frequent load changes and therefore triggers the switching element even when too low a force is applied.

[0004] Furthermore, the support load indicators cannot be used to make any quantitative calculations regarding the forces transmitted by the landing gear.

[0005] Consequently, the present invention was based on the object of providing a landing gear that allows a quantitative and reproducible measurement of the forces transmitted from the landing gear to the ground. Summary of the Invention

[0006] The basic object is solved according to the invention with the features of claim 1. By means of a force measuring element integrated in the support component it is possible to determine whether the trailer to be uncoupled is safely parked and, in particular in the case of semi-trailers, whether the landing gear is in firm contact with the ground. In addition to this qualitative determination there is also a quantitative determination of the load acting on the landing gear. This makes it possible to determine the total weight of the trailer by recording the axle loads and thereby to determine potential overloads or uneven load distribution.

[0007] Force measuring elements are understood to be sensors that generate a signal proportional to the force introduced from the deformation of the support component. These are, for example, piezoelectric sensors that detect the change in electric polarization and hence the generation of a voltage on a solid body when the solid body is elastically deformed. Alternatively, capacitive sensors can be used as force measuring elements.

[0008] The force measuring element is preferably attached to the support component and fastened in or on the surface of the support component. All fastening locations have in common that the force measuring element is connected to the support component in such a way as to detect its deformation as precisely as possible, whereby a force-locking, material-locking and / or form-locking connection is suitable, in particular by means of a precisely fitting clamping or adhesive bond.

[0009] The thrust bearing of the spindle is advantageously located below the spindle bearing plate. It surrounds the spindle and ensures that the spindle is rotatably supported while at the same time supporting the spindle under axial pressure against the spindle bearing plate. However, the spindle is supported radially through a spindle opening in the spindle bearing plate.

[0010] According to a particularly useful embodiment, the thrust bearing is supported with its upper bearing section on the underside of the support component, at least when the spindle is in a loaded state, the upper bearing section of the thrust bearing thereby being arranged in a stationary manner with respect to the support component, at least under load.

[0011] According to a first preferred embodiment, the support component is a spindle bearing plate. Alternatively, the support component can also be a measuring plate arranged between the upper bearing section of the thrust bearing and the spindle bearing plate. The measuring plate is, for example, shaped as a measuring wheel coaxially surrounding the spindle.

[0012] The measuring plate is preferably mounted in a rotatably fixed manner relative to the outer tube, which provides the advantage that the connecting cable can be laid in a stationary manner.

[0013] The measuring plate can in particular have a concave or bridge-like shape in which the outer support section faces the spindle bearing plate and the cantilever section is arranged between them. Due to this shape, there is always a free installation space for the spindle bearing plate in the area of ​​the cantilever section, into which, for example, a force measuring element can be inserted in a particularly protected manner. Furthermore, the concave or bridge-like shape of the measuring plate ensures a larger deformation of the measuring plate in the area of ​​the cantilever section when a force is introduced from the thrust bearing, which introduces an axially directed force in the center of the cantilever section, allowing a relatively large deformation and therefore a more accurate force measurement.

[0014] The thrust bearing can rest, in particular with its lower bearing section, on a spindle retaining ring which is rigidly connected to the spindle. The lower bearing section is therefore arranged rotatably relative to the support component and is stationary relative to the spindle. When the spindle is loaded, the support component presses the lower bearing section from below, forcing the thrust bearing with its upper bearing section against the support component, which deforms as a result of the introduced load.

[0015] The force measuring element is expediently located above the thrust bearing and at least partially within it. projection surface In this area, the load is introduced into the support component via the thrust bearing and the deformation measurable by the force measuring element is at its maximum, allowing a particularly precise and reproducible determination of the introduced force.

[0016] According to a further embodiment of the invention, the force-measuring element is expediently pin-shaped and is inserted without play or under prestress into a complementary-shaped recess in the support component.

[0017] Particularly useful is the embodiment in which the pin-shaped force measuring element is a measuring dowel. A measuring dowel is understood to mean a sensor that senses forces in the transverse direction, which is typically designed with a cylindrical shape and is always inserted with a precision fit and / or under prestress into a complementary shaped measuring dowel hole in the component to be measured, or at least when an expected operating load is present. Pretensioning of the measuring dowel is realized, for example, by a clamping device integrated into the measuring dowel.

[0018] Preferably, the recess is a measurement dowel hole formed in the support component, into which the measurement dowel is inserted. The diameter of the measurement dowel hole is typically 6.00 mm to 10.00 mm, particularly preferably 8 mm.

[0019] The measurement dowel holes can be, for example, radially aligned with the spindles in the support component. The measurement dowel holes are also preferably arranged perpendicular to the adjacent walls of the outer tube, so that the length of the measurement dowel holes, and hence the weakening of the material of the support component, is as small as possible.

[0020] Advantageously, the measuring dowel hole passes through the axial bearing at least partially offset in the axial direction, which makes it possible to arrange the measuring dowel above the thrust bearing and in the area of ​​maximum force application.

[0021] The measuring dowel hole is advantageously shaped as a blind hole and the measuring dowel is inserted into the deepest part of the blind hole, which results in a particularly protected mounting position for the measuring dowel.

[0022] According to a further alternative embodiment, the force measuring element is a strain gauge attachment. The strain gauge attachment is used to record tensile and compressive deformations of a support component. It changes its electrical resistance even with small deformations and is used as a strain sensor. Typically, the strain gauge attachment is bonded to a support component that deforms minimally under load. Its deformation (elongation) under load then leads to a change in the electrical resistance of the strain gauge attachment.

[0023] The strain gauge attachment is preferably attached to the upper and / or underside of the support component, which has the advantage on the one hand that no weakening of the support component through drilling or milling has to be carried out and on the other hand that there is a maximum expansion or compression on the upper and underside of the support component, as a result of which particularly precise and reproducible measurement values ​​can be achieved.

[0024] The force measuring element is preferably a pressure sensor arranged between the measuring plate and the spindle bearing plate. Pressure sensors belong to the group of pressure measuring devices, which, as the first link in the measuring chain, convert the physical quantity of pressure (force per area) into an electrical output quantity as a measure of the pressure. Piezoresistive or piezoelectric, capacitive or inductive pressure sensors and pressure sensors with Hall elements are particularly suitable.

[0025] A particularly useful embodiment of the invention can provide that the pressure sensor is arranged on a cantilever section of a concave or bridge-like measuring plate, such that a force branch occurs via the pressure sensor to the spindle bearing plate. This has the advantage that the pressure sensor does not have to transmit the entire power flow of the landing gear and is therefore largely protected against overloads. The spectrum of transmitted forces is also smaller, so that a pressure sensor with a narrower measuring range can be used, which in turn provides more precise measurements.

[0026] For a better understanding, the invention is explained in more detail below using the nine figures shown below. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a longitudinal section through a landing gear according to a first embodiment having a pin-shaped force measuring element in the spindle bearing plate. [Diagram 2] FIG. 2 is a cross-sectional view through the landing gear according to FIG. 1 in the cross-sectional plane CC. [Diagram 3] FIG. 3 is an enlarged cross-sectional view of detail X of FIG. 2. [Figure 4] FIG. 13 is a longitudinal section through the upper section of a landing gear according to a second embodiment having a pin-shaped force measuring element in the spindle bearing plate. [Diagram 5] FIG. 1 is a longitudinal section through a schematic example landing gear with strain gauge attachments as force measuring elements on the spindle bearing plate. [Figure 6]FIG. 2 is a longitudinal section through a schematic example landing gear with pin-shaped force measuring elements in the measuring plate; [Figure 7] FIG. 13 is a longitudinal section through a schematic example landing gear with strain gauge attachments as force measuring elements on a measuring plate. [Figure 8] FIG. 2 is a longitudinal section through a schematic example landing gear with a concave or bridge-shaped measurement plate and a force measurement element inserted therein. [Figure 9] FIG. 1 is a longitudinal section through a schematic example landing gear having a concave or bridge-shaped measurement plate and a pressure sensor disposed between the cantilever section and the spindle bearing plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] 1 shows a longitudinal section of a landing gear having an outer tube 20 in the form of a square profile and an axially guided inner tube 30. Due to the complementary profile shapes of the outer tube 20 and the inner tube 30, the inner tube 30 is held in the outer tube 20 in a circumferentially non-rotatably fixed manner.

[0029] Mounting flange plates 28 protrude from either side of the outer tube 20 and have mounting holes 29 formed at discrete intervals in the mounting flange plates 28 for fastening the landing gear to the vehicle. The inner tube 30 has support feet 32 ​​at its lower end which allow the landing gear to stand on the ground when the inner tube 30 is extended.

[0030] The outer tube 20 has a transmission assembly 40 having a spindle 42 rotatably mounted relative to the outer tube 20 and a gear 41 connected to the spindle 42 in a rotatably fixed manner at its upper end section. The transmission assembly 40 is rotated by a gear set 49 and a transmission input shaft 47, in particular shown in FIG. 4. By rotating the spindle 42, the spindle nut 31, which is firmly inserted in the upper section 33 of the inner tube 30, moves either downward or upward depending on the direction of rotation. When the spindle nut 31 moves downward, it presses the inner tube 30 and the support foot 32 attached to the inner tube 30 towards the ground, and the landing gear is extended. When the spindle nut 31 moves upward, it lifts the inner tube 30 together with the support foot 32, and the landing gear is retracted.

[0031] The spindle 42 passes through a spindle bearing plate 21 arranged below the gear 41, the spindle bearing plate 21 being formed with a spindle opening 24, the inner diameter of which is selected to be only slightly larger than the outer diameter of the spindle 42. With the help of the spindle bearing plate 21 and the spindle opening 24, the spindle 42 is supported in its radial direction. The spindle bearing plate 21 is firmly connected to the inner wall of the outer tube 20 on at least three sides, preferably four sides. The spindle bearing plate 21 is aligned essentially orthogonally to the extent of the outer tube 20. The spindle 42 and the associated spindle opening 24 in the spindle bearing plate 21 are accommodated in the center of the outer tube 20.

[0032] The thrust bearing 43 is slid onto the spindle 42 under the spindle bearing plate 21, which in turn abuts the spindle retaining ring 46. As soon as the support foot 32 stands on the ground, the spindle retaining ring 46 pushes the thrust bearing 43 upwards until it contacts the underside 23 of the spindle bearing plate 21.

[0033] A recess 25, in particular a measuring dowel hole 25, which is aligned laterally to the spindle 42 and extends through the outer tube 20 at its end facing away from the spindle 42, is inserted into the spindle bearing plate 21. The recess 25 is particularly visible in the same type of landing gear in FIG. 2 as a view of the section plane CC according to FIG. 1 and in the enlarged view of FIG. 3. In the exemplary embodiment, the recess 25 is designed as a blind hole 26, the deepest part 27 of which is located in the spindle bearing plate 21 close to the spindle opening 24. In this exemplary embodiment, the recess 25 runs parallel to the mounting flange plate 28 and is therefore aligned in or relative to the direction of travel when the landing gear is mounted on the vehicle.

[0034] A pin-shaped force measuring element 10, in particular in the form of a measuring dowel 11, is inserted in a stationary manner into the recess 25 and clamped in the measuring dowel hole 25 against the spindle bearing plate 21. The position of the measuring dowel 11 shown by way of example is in the area of ​​the deepest part 27 and therefore above the thrust bearing 43. projection surface When the inner tube 30 is extended relative to the outer tube 20 and the support foot 32 stands on the ground, a force flow occurs from the support foot 32 through the inner tube 30, the spindle nut 31, the spindle 42 and the thrust bearing 43 into the spindle bearing plate 21. Since the spindle bearing plate 21 is non-positively connected to the outer tube 20 in its edge region, a comparatively maximum deformation occurs in the region of the spindle bearing plate 21 above the thrust bearing 43, which results in the most precise possible measurement of this deformation by the measuring dowel 11, which can be assigned to the corresponding supporting load.

[0035] The measuring dowels 25, arranged by way of example in the spindle bearing plate 21, also continue into the aligned extensions in the outer tube 20. A transition coupler 13 is inserted into the open end of the measuring dowels 25, with the help of which the measuring dowels 25 are closed to the outside, through which only the connecting cable 14 is led out of the measuring dowels 25. Via the connecting cable 14, the measuring dowels 11 are electrically connected to the on-board network of the vehicle (not shown here), from which the measuring dowels 11 are supplied with electrical energy. In addition, the measuring dowels 11 provide a force measurement signal to the vehicle via the connecting cable 14.

[0036] FIG. 4 shows an alternative embodiment in which the measurement dowel holes 25 are arranged in the spindle bearing plate 21 and the outer tube 20 offset by 90° and pass through the outer tube 20 at the back between the mounting flange plates 28.

[0037] For extension or retraction, the landing gear has a transmission input shaft 47, to which in particular a crank (not shown) can be connected in a rotatably fixed manner. With the help of the crank, the operator can rotate the transmission input shaft 47, whereby the inner tube 30 with the support feet 32 ​​either extends or retracts depending on the direction of rotation. In the illustration of FIG. 4, the inner tube 30 is in a retracted position relative to the outer tube 20.

[0038] The transmission input shaft 47 meshes with the gear 41 of the transmission assembly 40 and transmits torque to a gear set 49 which engages with the transmission output shaft 48. The transmission input shaft 47 and the transmission output shaft 48 are arranged axially parallel to each other. The recesses 25 or measurement dowel holes 25 also run parallel to the transmission input shaft 47 and the transmission output shaft 48.

[0039] The thrust bearing 43 of the spindle 42 is made up of two parts and includes an upper bearing section 44 disposed adjacent to the underside 23 of the spindle bearing plate 21. When the inner tube 30 is contracted into the outer tube 20, a gap may be formed between the upper bearing section 44 and the underside 23 of the spindle bearing plate 21 due to the weight of the inner tube 30 and the support foot 32, since in this contracted position the spindle 42 is supported in a hanging manner on the upper surface 22 of the spindle bearing plate 21 by its fixing bolts 42a.

[0040] With the inner tube 30 extended and the support foot 32 resting on the ground, the spindle 42 is pushed upwards and the spindle retaining ring 46 fixedly formed on the spindle 42 abuts against the lower bearing section 45 of the thrust bearing 43. With the help of the thrust bearing 43, the force is transmitted to the upper bearing section 44, which is pressed against the underside 23 of the spindle bearing plate 21 and rests thereon.

[0041] At the same time, the thrust bearing 43 allows the spindle 42 to rotate further even when the landing gear is under pressure.

[0042] The measurement dowel hole 25 running radially towards the spindle 42 is aligned and dimensioned so that the measurement dowel 11 clamped therein is located above the thrust bearing 43 and hence as close as possible to the force application point of the force transmitted from the spindle 42 into the spindle bearing plate 21.

[0043] 5 shows an alternative embodiment with a force measuring element 10 in the form of a strain gauge attachment 12. The strain gauge attachment 12 is attached to the upper surface 22 of the spindle bearing plate 21 and at least partially overlaps the thrust bearing 43 arranged below, via which a compressive force in the direction of the arrow is transmitted to the spindle bearing plate 21 when the support foot 32 stands on the ground. As a result, most of the deformation of the spindle bearing plate 21 takes place in the area of ​​the strain gauge attachment 12, which allows a particularly precise force measurement.

[0044] The strain gauge application portion 12 may be connected to the vehicle's energy and data systems by a connecting cable 14 .

[0045] Figure 6 shows a further illustrative embodiment in which the measuring plate 15 is inserted between the thrust bearing 43 of the spindle 42 and the spindle bearing plate 21 attached to the outer tube 20. The measuring plate 15 is provided with a central hole for receiving the spindle 42 and is designed in a closed ring shape. When the landing gear is extended and loaded, the measuring plate 15 is subjected to a compressive force from the spindle 42 moving upwards in the direction of the arrow, which presses the measuring plate 15 against the underside 23 of the spindle bearing plate 21 via the spindle retaining ring 46 and the thrust bearing 43. The spindle bearing plate 21 ensures that the force is transmitted to the outer tube 20 and from there to the vehicle via the mounting flange plate 28 (see Figure 1).

[0046] The measuring plate 15 has a recess 25, in particular a measuring dowel hole 25, into which a pin-shaped force measuring element 10, in particular a measuring dowel 11, is inserted as force measuring element 10. The recess 25 is aligned radially with respect to the spindle 42, and the pin-shaped force measuring element 10, in particular the measuring dowel 11, is located above a thrust bearing 43 of the spindle 42, which transmits forces into the measuring plate 15 when the landing gear is loaded.

[0047] In order to prevent the measuring plate 15 from rotating together with the spindle 42, the measuring plate 15 is connected in a rotatably fixed manner to the spindle bearing plate 21 via the measuring plate holder 16. As a result, the measuring plate 15 is held in a rotatably fixed manner relative to the outer tube 20 and the connecting cable 14 can be pulled out of the outer tube 20 in a defined position without a moving cable.

[0048] 7 shows a further exemplary embodiment with a measuring plate 15 provided with a strain gauge attachment part 12. The measuring plate 15 is designed with a concave or bridge-like shape and is supported in the event of load only in its lateral edge regions by support sections 17 on the underside 23 of the spindle bearing plate 21. The cantilever sections 18 located between the support sections 17 are always arranged at a distance from the underside 23 of the spindle bearing plate 21, regardless of the load on the thrust bearing 43, and support the strain gauge attachment part 12, which cannot collide with the spindle bearing plate 21 due to this installation location.

[0049] It is also possible to design the measuring plate 15 with the force measuring elements 10 as a measuring film of particularly thin construction. Here too, the measuring plate 15 is located in the force flow between the thrust bearing 43 and the outer tube 20, making it possible to measure any forces there.

[0050] 8 shows a further exemplary embodiment with a concave or bridge-like shape of the measuring plate 15, the rising support section 17 of which projects in the direction of the spindle bearing plate 21 relative to a cantilever section 18 arranged therebetween. A recess 25, in particular a measurement dowel hole 25, tapering radially towards the spindle 42, is formed in the measuring plate 15, into which a pin-shaped force measuring element 10, in particular a measurement dowel 11, is inserted. The force measuring element 10 is located in the area of ​​the cantilever section 18 of the measuring plate 15, which area undergoes a larger reversible deformation compared to the support section 17 when the landing gear is loaded, allowing a particularly precise measurement.

[0051] 9 shows a landing gear according to the invention according to an alternative embodiment, which also has a concave or bridge-like measuring plate 15. However, a pressure sensor 19 is used as force measuring element 10, which is arranged on the side of the cantilever section 18 facing the spindle bearing plate 21. The pressure sensor 19 is closed with its upper side on the support section 17 of the measuring plate 15 and rests on the underside 23 of the spindle bearing plate 21 together with the support section 17 when the landing gear is loaded, so that a force bifurcation occurs and the pressure sensor 19 is subjected to only a part of the total force transmitted from the thrust bearing 43 to the spindle bearing plate 21.

[0052] [List of reference numbers] 10 Force measuring elements 11 Pin-shaped force measuring element, measuring dowel 12 Strain gauge attachment part 13 Transition coupler 14 Connection cable 15 Measuring plate 16 Measuring plate holder 17 Support section(s) of measuring plate 18 Cantilever section of measuring plate 19 Pressure Sensor 20 outer tube 21 Spindle bearing plate 22 Top surface of spindle bearing plate 23 Underside of spindle bearing plate 24 Spindle opening of spindle bearing plate 25 Recess, measuring dowel hole 26 Blind Hole 27 Deepest part of the blind hole 28 Mounting flange plate 29 Mounting holes 30 Inner tube 31 Spindle nut 32 Support foot 33 Upper section of inner tube 40 Transmission Assembly 41 Gear 42 Spindle 42a Fixing bolt 43 Spindle thrust bearing 44 Upper Bearing Section 45 Lower Bearing Section 46 Spindle retaining ring 47 Transmission input shaft 48 Transmission output shaft 49 Gear Set The invention as originally claimed in the present application is set forth below. [1] A landing gear having a force measuring element (10), the landing gear comprising an outer tube (20), an inner tube (30) movably mounted in the outer tube (20), and a transmission assembly (40) comprising at least one spindle (42) driven by a gear (41), the spindle (42) being provided through a spindle opening (24) in a spindle bearing plate (21) in contact with the outer tube (20), a spindle nut (31) fastened to the inner tube (30) being held on the spindle (42), 1. A landing gear, characterized in that the force measuring element (10) is mounted on a support component (15, 21) arranged in the force flow between the spindle (42) and the outer tube (20). [2] A landing gear according to [1], characterized in that a force is detected by the force measuring element (10) in response to a deformation of the support components (15, 21). [3] A landing gear as described in [1] or [2], characterized in that a thrust bearing (43) of the spindle (42) is arranged below the spindle bearing plate (21). [4] A landing gear as described in [3], characterized in that the thrust bearing (43) is supported under load at its upper bearing section (44) on the underside (23) of the support component (15, 21). [5] A landing gear as described in any one of [1] to [4], characterized in that the support component (15, 21) is the spindle bearing plate (21). [6] The landing gear according to [4], characterized in that the support component (15, 21) is a measuring plate (15) arranged between the upper bearing section (44) of the thrust bearing (43) and the spindle bearing plate (21). [7] A landing gear as described in [6], characterized in that the measuring plate (15) is mounted in a rotatably fixed manner relative to the outer tube (20). [8] The landing gear according to [6] or [7], characterized in that the measuring plate (15) has a concave or bridge-like shape with an external support section (17) facing the spindle bearing plate (21) and a cantilever section (18) arranged therebetween. [9] A landing gear as described in any one of [3] to [8], characterized in that the thrust bearing (43) is mounted at its lower bearing section (45) on a spindle retaining ring (46) firmly connected to the spindle (42).

[10] A landing gear as described in any one of [3] to [9], characterized in that the force measuring element (10) is arranged above the thrust bearing (43) and at least partially within its projection plane.

[11] A landing gear according to any one of [1] to

[10] , characterized in that the force measuring element (10) is pin-shaped and is inserted without play or under tension into a complementarily shaped recess (25) of the support component (15, 21).

[12] The landing gear according to

[11] , characterized in that the pin-shaped force measuring element (10) is a measuring dowel (11).

[13] A landing gear as described in

[11] or

[12] , characterized in that the recess (25) is a measurement dowel hole (25) formed in the support component (15, 21) into which the measurement dowel (11) is inserted.

[14] The landing gear according to

[13] , characterized in that the measuring dowel (11) is mechanically fixed in the measuring dowel hole (25).

[15] A landing gear as described in

[13] or

[14] , characterized in that the measurement dowel hole (25) is radially aligned with the spindle (42).

[16] The landing gear according to any one of [1] to

[10] , wherein the force measuring element (10) is a strain gauge attachment portion (12).

[17] The landing gear according to

[16] , characterized in that the strain gauge attachment portion (12) is attached to the upper surface (22) and / or the lower surface (23) of the support component (15, 21).

[18] A landing gear as described in any one of [6] to [8], characterized in that the force measuring element (10) is a pressure sensor (19) arranged between the measuring plate (15) and the spindle bearing plate (21).

[19] A landing gear according to

[18] citing [8], characterized in that the pressure sensor (19) is arranged on the cantilever section (18) of the measuring plate (15) such that a force branch occurs on the spindle bearing plate (21) via the pressure sensor (19).

Claims

1. A landing gear having a force measuring element (10), said landing gear comprising an outer tube (20), an inner tube (30) movably mounted in said outer tube (20), and a transmission assembly (40) comprising at least one spindle (42) driven by a gear (41), said spindle (42) being provided through a spindle opening (24) in a spindle bearing plate (21) in contact with said outer tube (20), a spindle nut (31) fastened to said inner tube (30) being held on said spindle (42), the force measuring element (10) is mounted on a support component (15, 21) arranged in the force flow between the spindle (42) and the outer tube (20), 13. A landing gear, characterized in that forces are detected by said force measuring element (10) as a function of deformations of said support components (15, 21).

2. 2. A landing gear according to claim 1, characterized in that the thrust bearing (43) of the spindle (42) is arranged below the spindle bearing plate (21).

3. 3. A landing gear according to claim 2, characterized in that the thrust bearing (43) is supported under load with its upper bearing section (44) on the underside (23) of the support component (15, 21).

4. A landing gear according to any one of claims 1 to 3, characterized in that the support component (15, 21) is the spindle bearing plate (21).

5. 4. A landing gear according to claim 3, characterized in that the support component (15, 21) is a measuring plate (15) arranged between the upper bearing section (44) of the thrust bearing (43) and the spindle bearing plate (21).

6. A landing gear according to claim 5, characterized in that the measuring plate (15) is mounted in a rotatably fixed manner relative to the outer tube (20).

7. 7. A landing gear according to claim 5 or 6, characterized in that the measuring plate (15) has a concave or bridge-like shape with an outer support section (17) facing the spindle bearing plate (21) and a cantilever section (18) arranged therebetween.

8. A landing gear according to claim 2 or any one of claims 3 to 7 which depend on claim 2, characterized in that the thrust bearing (43) rests with its lower bearing section (45) on a spindle retaining ring (46) which is rigidly connected to the spindle (42).

9. A landing gear according to claim 2 or any one of claims 3 to 8 which depend on claim 2, characterized in that the force measuring element (10) is arranged in its projection plane at least partially above the thrust bearing (43).

10. 10. A landing gear according to any one of claims 1 to 9, characterized in that the force measuring element (10) is pin-shaped and is inserted without play or under tension into a complementary shaped recess (25) of the support component (15, 21).

11. 11. Landing gear according to claim 10, characterized in that the pin-shaped force measuring element (10) is a measuring dowel (11).

12. 12. A landing gear according to claim 11, characterized in that the recess (25) is a measurement dowel hole (25) formed in the support element (15, 21) and into which the measurement dowel (11) is inserted.

13. 13. A landing gear according to claim 12, characterized in that the measuring dowels (11) are mechanically fixed in the measuring dowel holes (25).

14. 14. A landing gear according to claim 12 or 13, characterized in that the measuring dowel holes (25) are radially aligned with the spindle (42).

15. A landing gear according to any one of the preceding claims, characterized in that the force measuring element (10) is a strain gauge attachment (12).

16. 16. A landing gear according to claim 15, characterized in that the strain gauge attachment (12) is attached to the upper side (22) and / or the underside (23) of the support element (15, 21).

17. A landing gear according to any one of claims 5 to 7, characterized in that the force measuring element (10) is a pressure sensor (19) arranged between the measuring plate (15) and the spindle bearing plate (21).

18. 18. A landing gear according to claim 17, dependent on claim 7, characterized in that the pressure sensor (19) is arranged on the cantilever section (18) of the measuring plate (15) in such a way that a force branch occurs via the pressure sensor (19) on the spindle bearing plate (21).

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