Support winch with one support foot and one power measuring element

Description

[0001] The invention relates to a landing gear with a support leg and a force measuring element according to the features in the preamble of claim 1.

[0002] Such landing gears are often mounted on semi-trailers or trailers in general and support them on the ground, particularly when uncoupled from the towing vehicle. This ensures that the semi-trailer remains stable in its parked position and can be approached for re-coupling by a towing vehicle. In other applications, landing gears are mounted on the rear of silo vehicles and are extended to stabilize the vehicle before the tipping process begins.

[0003] DE 10 2005 036 139 A1 discloses a landing gear with a pressure element and a support load indicator, which indicates to the operator that the landing gear is secure when the landing gear is extended. The pressure element comprises a spring element and a cooperating switching element in the form of a mechanical switch, wherein the spring element is arranged between a spindle stop ring fixedly mounted on the spindle and the spindle bearing plate. During the extension of the landing gear, if the ground is stable, the spindle moves against the spindle bearing plate, causing the spring element to deform and actuate the switching element. The switching element, in turn, is connected to an indicator element that indicates to the operator that the landing gear is loaded.However, it has proven disadvantageous that the spring element does not provide reproducible values ​​after frequent load changes, thus triggering the switching element even with insufficient force. Furthermore, the support load indicator does not provide a quantitative statement about the forces transmitted by the landing gear.

[0004] DE 10 2016 104592 A1 discloses a landing gear similar to the preamble of claim 1.

[0005] Consequently, the object of the invention was to provide a support winch that enables a quantitative and reproducible measurement of the forces transmitted from the support winch to the ground.

[0006] The object is achieved according to the invention with the features of claim 1. A force measuring element attached to the foot support element can be used to determine whether a trailer to be uncoupled is parked safely and, particularly in the case of a semi-trailer, whether the landing gears have firm ground contact. In addition to this qualitative determination, a quantitative determination of the load acting on the landing gears is also performed. This, together with the measurement of the axle loads, makes it possible to determine the total weight of the trailer and thus detect potential overloading or uneven load distribution.

[0007] The foot support element is a component located in the force flow between the support foot and the inner tube of the landing gear. Typically, the foot support element is firmly connected to the inner tube, especially by welding. This provides additional stiffening to the inner tube at its lower end thanks to the foot support element.

[0008] A force measuring element is a sensor that generates a signal proportional to the applied force from the deformation of the foot support element. Piezoelectric sensors, for example, detect the change in electrical polarization and thus the occurrence of an electrical voltage in solid bodies when they are elastically deformed. Alternatively, capacitive sensors can also be used.

[0009] The force measuring element is attached to the foot receiving element, with fastening of the force measuring element within the foot receiving element or on the surface of the foot receiving element being preferred. What all fastening positions have in common is that the force measuring element is connected to the foot receiving element in such a way that it detects its deformation as precisely as possible. A force-fitting, material-fitting, and / or form-fitting connection is particularly suitable, in particular by precisely fitting clamping or gluing. Using the force measuring element, a force can be determined as a function of the deformation of the foot receiving element.

[0010] According to a first preferred embodiment, the foot receiving element has a main body, with which the foot receiving element is fastened to the inner tube, and two bearing pins protruding from the main body on opposite sides. The main body can be shaped complementarily to the inner contour of the inner tube, inserted into the inner tube from below, and preferably integrally connected to it. In the axial direction, at least a lower section of the inner tube overlaps the main body inserted therein, thereby increasing the overall wall thickness in the area of ​​the loads introduced by the support foot. The bearing pins engage, for example, the main body. A particularly preferred embodiment is one in which the bearing pins and the main body form a one-piece, integral unit. The support foot is pivotally attached to the bearing pins.

[0011] According to a second, alternative embodiment, the foot support element comprises an axle tube projecting laterally beyond the inner tube, to which the support foot is pivotally mounted. The axle tube can be a hollow body or a solid body. The inner tube can be provided with corresponding, aligned openings to accommodate the axle tube. It is also possible to insert the axle tube into separate bearing sleeves, which in turn are firmly connected to the inner tube and aligned with each other. The bearing sleeves can be inserted into openings in the inner tube or connected from below to the front end of the inner tube.

[0012] The force measuring element can then be attached to the main body, to one of the bearing journals or to the axle tube.

[0013] The force measuring element can in particular be pin-shaped and inserted into a complementarily shaped recess of the foot receiving element without play or under preload.

[0014] A particularly useful embodiment is one in which the pin-shaped force measuring element is a measuring dowel and the recess is a measuring dowel bore into which the measuring dowel is inserted. A measuring dowel is understood to be a transversely force-sensitive sensor that is typically cylindrical in shape and is inserted into a complementarily shaped measuring dowel bore in the component to be measured, always or at least when the expected operating load is present, with a precise fit and / or under preload. The preload of the measuring dowel is achieved, for example, by means of a clamping device integrated into the measuring dowel. The diameter of the measuring dowel bore is typically 6.00 mm to 10.00 mm, particularly preferably 8 mm.

[0015] According to a particularly useful design, the measuring dowel is mechanically clamped in the measuring dowel bore. This allows the measuring dowel to be removed and reinserted for maintenance and repair purposes. Replacing the measuring dowel with a cast or glued connection within the measuring dowel bore would be much more complex.

[0016] Conveniently, the recess is located in one of the bearing journals or the axle tube. Both components directly absorb the forces transmitted by the support leg and are therefore subject to a deformation under load, which is detected by the pin-shaped force measuring element.

[0017] The recess is advantageously aligned in the axial direction of the bearing journal or axle tube. This results in the advantage that the pin-shaped force measuring element is subjected to bending stress on the bearing journal or axle tube when the support foot is resting on the ground, enabling particularly precise measurement of the force acting on the landing gear. Measurement accuracy can be further improved if the recess is positioned eccentrically to the center axis of the bearing journal or axle tube, on a side facing away from the outer and / or inner tube. In this area, the bearing journal or axle tube undergoes stretching, the magnitude of which increases with increasing eccentricity, further improving measurement accuracy.

[0018] Conveniently, the recess on one end of the bearing journal or axle tube is formed as a blind hole. This makes it possible to position the pin-shaped force measuring element in an area of ​​the greatest applied forces without weakening the bearing journal or axle tube with an unnecessarily long recess.

[0019] Advantageously, the pin-shaped force measuring element is inserted into the deepest part of the blind hole. This results in a particularly protected mounting position for the pin-shaped force measuring element.

[0020] The support foot can have a base plate on which two wall sections projecting upwards to the sides of the inner tube are formed, in which wall sections a bearing opening is formed for receiving the bearing journals or the axle tube, wherein at least a section of the pin-shaped force measuring element is arranged between the adjacent wall section and a downwardly projected plane of the inner tube. The force flows from the support foot via the wall sections to the bearing journals or the axle tube and from there optionally via the main body to the inner tube. In an area between the wall section and the inner tube or its downward extension, the bearing journal or the axle tube to be monitored by means of the pin-shaped force measuring element undergoes the greatest deformation, which enables particularly precise measurements by the pin-shaped force measuring element.

[0021] According to another alternative embodiment, the force measuring element is a strain gauge application. The strain gauge application is used to detect stretching and compressive deformations of the foot support element. It changes its electrical resistance even with slight deformations and is used as a strain sensor. Typically, the strain gauge application is glued to the foot support element, which deforms minimally under load. Its deformation under load then leads to a change in the electrical resistance of the strain gauge application.

[0022] Preferably, the strain gauge application is mounted on the top and / or bottom of the main body. This results in the advantage that the base support element does not need to be weakened by drilling or milling, and that there is expansion or compression on the top and bottom of the main body, thus enabling particularly precise and reproducible measurement values. Since the strain gauge application is usually located on the surface of the component to be monitored, mounting it on the main body, particularly on its top side, which is protected within the inner tube, is preferred.

[0023] As an alternative to the embodiment described above, the strain gauge application can be applied to the axle tube and record its deformation under load.

[0024] For a better understanding, the invention is explained in more detail below with reference to six figures. Fig. 1: a longitudinal section through a landing gear with a support leg mounted on it; Fig. 2: a longitudinal section rotated by 90° through the lower section of the landing gear according to Fig. 1 with a force measuring element according to a first embodiment; Fig. 3: a side view of the lower section of the landing gear according to Fig. 1 ; Fig. 4: a schematic longitudinal section through a support winch with a force measuring element according to a second embodiment; Fig. 5: a schematic longitudinal section through a support winch with a force measuring element according to a third embodiment and Fig. 6: a schematic longitudinal section through a support winch with a force measuring element according to a fourth embodiment.

[0025] The Fig. 1 shows a longitudinal section of a landing gear with an outer tube 20 in the form of a square profile and an inner tube 30 guided axially therein. Due to the complementary profile shape of the outer and inner tubes 20, 30, the inner tube 30 is held in the outer tube 20 in a rotationally fixed manner in the circumferential direction.

[0026] To secure the landing gear to a vehicle, a mounting flange plate 23 protrudes on both sides of the outer tube 20, in which mounting holes 24 are provided at discrete intervals. The inner tube 30 carries a support foot 60 at its lower end, with which the landing gear rests on the ground when the inner tube 30 is extended.

[0027] Arranged in the outer tube 20 is a gear arrangement 50 comprising a spindle 52 mounted rotatably relative to the outer tube 20 and a gear 51 which is connected to the spindle 52 at an upper end section thereof in a rotationally fixed manner. When the spindle 52 rotates, a spindle nut 31 fixedly inserted into an upper section 32a of the inner tube 30 moves either downwards or upwards, depending on the direction of rotation. When the spindle nut 31 moves downwards, it presses the inner tube 30 and the support foot 60 attached to it towards the ground, and the support jack is extended. When the spindle nut 31 moves upwards, it lifts the inner tube 30 and the support foot 60, and the support jack is retracted.

[0028] The spindle 52 passes through a spindle bearing plate 21 arranged below the gear 51, which is formed with a spindle opening 22 whose inner diameter is selected to be only slightly larger than the outer diameter of the spindle 52. The spindle 52 is mounted in its radial direction by means of the spindle bearing plate 21 and the spindle opening 22. The spindle bearing plate 21 is firmly connected to the inner wall of the outer tube 20 on at least three sides, preferably on four sides. The spindle bearing plate 21 is aligned essentially orthogonally to the extension of the outer tube 20. The spindle 52 and the associated spindle opening 22 in the spindle bearing plate 21 are accommodated centrally in the outer tube 20.

[0029] In the Fig. 2 A lower section 32b of the inner tube 30 with the support foot 60 attached thereto is shown. The support foot 60 is pivotally mounted on a foot receiving element 40, which in turn is fixedly secured to the inner tube 30 in the region of the lower section 32b. In the illustrated embodiment, the foot receiving element 40 has a main body 41 and two bearing pins 43 projecting on opposite sides relative to the inner tube 30. The bearing pins 43 project laterally outward beneath the inner tube 30 and / or outer tube 20.

[0030] The main body 41 is designed with a shape complementary to the inner contour of the inner tube 30, is inserted into the inner tube 30 from below at the front end, and is permanently connected to it. In the maximally raised position of the inner tube 30, the bearing pins 43 abut the outer tube 20 at the front end. Typically, the main body 41 at least partially overlaps the inner tube 30 from the inside and protrudes downward from it.

[0031] The support foot 60 comprises a substantially flat base plate 61, onto which two vertically upstanding wall sections 62 are formed. The inner tube 30 and the outer tube 20 are arranged between the two wall sections 62. Each wall section 62 has a mutually aligned bearing opening 63 through which the bearing pins 43 of the foot receiving element 40 extend. The bearing pin 43 on the right in the image plane is constructed in two parts for simplified assembly of the support foot 60 to the foot receiving element 40 and has a detachable mounting end piece 43a, which is fastened to the bearing pin 43 by means of a screw 43b. When the support foot 60 is mounted on the foot receiving element 40, the support foot 60 oscillates about a central axis x of the bearing pins 43.

[0032] A recess 42 running parallel to the central axis x is formed in an end face 44 of one of the two bearing journals 43, which recess may, for example, be a measuring dowel bore 42. In the present exemplary embodiment, the recess 42 is designed as a blind hole 45, the borehole depth 46 of which extends to a downwardly extending, projected plane y in extension of the inner tube 30. A force measuring element 10 in the form of a pin-shaped force measuring element 10, in particular a measuring dowel 11, is fixedly inserted into the recess 42 and clamped within the recess 42 relative to the associated bearing journal 43.

[0033] The position of the pin-shaped force measuring element 10 is in the area between the nearest wall section 62 and the borehole depth 46. When the inner pipe 30 is extended relative to the outer pipe 20 and the support foot 60 rests on the ground, a force flow occurs from the support foot 60 via the bearing pins 43 to the inner pipe 30. As a result, the bearing pin 43 between the wall section 62 and the main body 41 is subjected to bending stress and a relatively large deformation occurs, which enables precise measurement by means of the pin-shaped force measuring element 10 and whose measured value can be assigned to a corresponding support load.

[0034] In Fig. 3 The lateral overlap of the wall section 62 with the outer tube 20 and the inner tube 30 is particularly clearly visible when the support winch is retracted. When the support winch is extended, the wall sections 62 overlap only with the inner tube 30.

[0035] Both the Fig. 2 as well as the Fig. 3 reveal the eccentric alignment of the force measuring element 10 within the bearing journal 43. Due to the bending stress under load, the force measuring element 10 is located on a side of the bearing journal 43 facing the base plate 61, which is subject to greater stretching with increasing eccentricity to the central axis x.

[0036] A transition coupling 13 is inserted into an open end of the recess 42, closing the recess 42 from the outside and through which only a connecting cable 14 is led out of the recess 42. Via the connecting cable 14, the force measuring element 10 is electrically connected to an on-board network of a vehicle (not shown here), from which the force measuring element 10 is supplied with electrical energy. Furthermore, the force measuring element 10 provides the force measurement signals to the vehicle via the connecting cable 14.

[0037] The Fig. 4 represents an alternative embodiment with a force measuring element 10 in the form of a strain gauge application 12. The strain gauge application 12 is preferably applied to an upper side 41a of the main body 41 and is located in a protected position within the contour of the inner tube 30. In principle, it would also be possible to attach the strain gauge application 12 to an underside 41b of the main body 41, which, however, is exposed to considerable environmental influences during driving.

[0038] The strain gauge application 12 can be connected to the energy and data system of a vehicle not shown here by means of a connecting cable 14.

[0039] In the Fig. 5 A further embodiment of the landing gear is shown, in which the foot support element 40 comprises an axle tube 47. The axle tube 47 is a continuous component with a circular cross-section. The axle tube 47 runs under opposite wall sections of the inner tube 30 and protrudes laterally relative to the inner tube 30 to such an extent that the bearing openings 63 of the wall sections 62 are also penetrated by the axle tube 47. The support foot 60 is pivotally mounted on the axle tube 47.

[0040] To stiffen the lower section 32b of the inner tube 30 and to reduce the surface pressure in this area, aligned bearing sleeves 48 are firmly attached to the inner tube 30, through which the axle tube 47 passes. The axial alignment of both bearing sleeves 48 is essentially perpendicular to the axial extension of the inner tube 30.

[0041] A force-measuring element 10 in the form of a strain gauge application 12 is applied to the surface of the axle tube 47. In the present embodiment, the strain gauge application 12 is located on a side of the axle tube 47 facing the base plate 61 of the support foot 60. Particularly preferred is an arrangement of the strain gauge application 12 between the wall sections of the inner tube 30, in particular between the two spaced-apart bearing sleeves 48.

[0042] The Fig. 6 showed a further embodiment of the invention with a foot support element in the form of an axle tube 47, the wall thickness of which is sufficient to provide a recess 42, in particular a measuring dowel bore 42. A pin-shaped force measuring element 10, in particular a measuring dowel 11, is inserted into the recess 42 and releasably clamped therein. The recess 42 is located on a side of the axle tube 47 facing the base plate 61.

[0043] Furthermore, the recess 42, which is also designed as a blind hole 45, opens at the end face 44 of the axle tube 47 and ends with its borehole depth 46 in overlap with the adjacent bearing sleeve 48. In this respect, at least a section of the pin-shaped force measuring element 10 is also arranged between the wall section 62 of the support foot 60 and a projected plane y in extension of the inner tube 30 in this embodiment. Bezugszeichenliste

[0044] 10Force measuring element 11Pin-shaped force measuring element, measuring dowel 12Strain gauge application 13Transition coupling 14Connecting cable 20Outer tube 21Spindle bearing plate 22Spindle opening Spindle bearing plate 23Mounting flange plate 24Mounting holes 30Inner tube 31Spindle nut 32upper section of inner tube 32lower section of inner tube 40Foot support element 41Main body 41aTop of main body 41bBottom of main body 42Recess, measuring dowel hole 43Bearing journal 43aMounting end piece 43bScrew 44End face of bearing journal / axle tube 45Blind hole 46Deepest hole 47Axle tube 48Bearing sleeves axle tube 50Gear arrangement 51Gear 52Spindle 60Support foot 61Base plate 62Wall section 63Storage opening xCenter axis of bearing journal yProjected plane

Claims

1. A support jack comprising a support foot (60) and a force measuring element (10), wherein the support jack has an outer tube (20) and an inner tube (30) movably mounted therein, and the support foot (60) is pivotably secured to the inner tube (30) by means of a foot receiving element (40), wherein the force measuring element (10) is attached to the foot receiving element (40), characterized in that, a force is determined by means of the force measuring element (10) as a function of the deformation of the foot receiving element (40).

2. The support jack according to claim 1, characterized in that the foot receiving element (40) has a main body (41), with which the foot receiving element (40) is fastened to the inner tube (30), and two bearing pins (43) projecting on opposite sides of the main body (41).

3. The support jack according to claim 1, characterized in that the foot receiving element (40) has an axle tube (47) which projects laterally beyond the inner tube (30) and to which the support foot (60) is pivotally attached.

4. The support jack according to claim 2 or 3, characterized in that the force measuring element (10) is attached to the main body (41), to one of the bearing pins (43) or the axle tube (47).

5. The support jack according to one of claims 1 to 4, characterized in that the force measuring element (10) is pin-shaped and is inserted into a complementary shaped recess (42) of the foot receiving element (40) without play or under prestress.

6. The support jack according to claim 5, characterized in that the pin-shaped force measuring element (10) is a measuring dowel (11) and the recess (42) is a measuring dowel bore (42) into which the measuring dowel (11) is inserted.

7. The support jack according to claim 5 or 6 as far as referred to claim 2 or 3, characterized in that the recess (42) is arranged in one of the bearing pins (43) or the axle tube (47).

8. The support jack according to claim 7, characterized in that the recess (42) is aligned in the axial direction of the bearing pin (43) or the axle tube (47).

9. The support jack according to claim 7 or 8, characterized in that the recess (42) is arranged eccentrically to a center axis (x) of the bearing pin (43) or the axle tube (47), on a side facing away from the outer and / or inner tube (20, 30).

10. The support jack according to one of claims 7 to 9, characterized in that the recess (42) is formed as a blind hole (45) on a front side (44) of the bearing pin (43) or the axle tube (47).

11. The support jack according to claim 10, characterized in that the pin-shaped force measuring element (10) is inserted into the borehole deepest (46) of the blind hole (45).

12. The support jack according to one of claims 7 to 11, characterized in that the support foot (60) has a base plate (61), on which two wall sections (62) are formed projecting laterally with respect to the inner tube (30), wherein a bearing opening (63) is formed in the wall sections (62) for receiving the bearing pins (43) or the axle tube (47), at least a section of the pin-shaped force measuring element (10) being arranged between the adjacent wall section (62) and a downwardly projected plane (y) of the inner tube (30).

13. The support jack according to one of claims 1 to 4, characterized in that the force measuring element (10) is a strain gauge application (12).

14. The support jack according to claim 13, characterized in that the strain gauge application (12) is applied to an upper and / or lower side (41a, 41b) of the main body (41).

15. The support jack according to claim 13 as far as referred to claim 3, characterized in that the strain gauge application (12) is applied to the axle tube (47).