Support jack comprising support feet and force measuring elements

Abstract

The invention relates to 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 in the outer tube, and the support foot (60) is pivotably fixed to the inner tube (30) by means of a foot receiving element (40). The object of the invention is to provide a support jack which allows a quantitative and reproducible measurement of the force transmitted from the support jack to the underlying surface. This is achieved by the force measuring element (10) being attached to the foot receiving element (40).

Description

Technical Field

[0001] The present invention relates to a support jack comprising a support foot and a force measuring element as described in the preamble of claim 1. Background Technology

[0002] Such support jacks are typically attached to the semi-trailer or trailer and support them on the ground, especially when disengaged from the towing vehicle. As a result, the semi-trailer remains stable in its parking position and can be approached by the towing vehicle for re-engagement. In other applications, support jacks are positioned at the rear of the silo vehicle and extend to stabilize the vehicle before the unloading process begins.

[0003] A support jack comprising a pressure element and a support load indicator is known from DE 10 2005 036 139A1, which indicates a safe position to the operator when the support jack is extended. The pressure element comprises a spring element and a switching element interacting with the spring element in the form of a mechanical button, the spring element being arranged between a spindle retaining ring and a spindle bearing plate, which are stationary on the spindle. When the support jack is extended, if the surface is stable, the spindle moves against the spindle bearing plate, causing the spring element to deform and actuate the switching element. The switching element is then connected to a display element that indicates to the operator the presence of a loaded support jack. However, it has been shown to be disadvantageous that the spring element no longer delivers a reproducible value after frequent load changes, thus triggering the switching element even with too low a force. Furthermore, the support load indicator cannot be used to make any quantitative statement about the force transmitted by the support jack. Summary of the Invention

[0004] Therefore, the objective of this invention is based on providing a support jack that enables quantitative and reproducible measurement of the force transmitted from the support jack to the ground.

[0005] According to the invention, this objective is achieved with the features of claim 1. By means of a force-measuring element attached to the foot receiving element, it can be determined whether the trailer to be disengaged is safely parked, and particularly in the case of a semi-trailer, whether the support jack 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 support jack. This makes it possible to determine the total weight of the trailer by recording the axle load and thereby identify potential overloads or uneven load distribution.

[0006] A foot receiving element is a component arranged between a support foot and the inner tube of the supporting jack to facilitate the flow of force. Typically, the foot receiving element is securely connected to the inner tube, particularly by welding. As a result, the inner tube is further reinforced at its lower end by the foot receiving element.

[0007] Force-measuring elements are sensors that generate a signal proportional to the force introduced by the deformation of the foot-receiving element. These sensors are, for example, piezoelectric sensors, which detect changes in polarization and thus detect the occurrence of voltage on the solid during elastic deformation. Alternatively, capacitive sensors can also be used.

[0008] A force-sensing element is attached to a foot receiving element, preferably fastened to the foot receiving element or its surface. All fastening locations share the characteristic that the force-sensing element is connected to the foot receiving element so that it can detect deformation of the foot receiving element as accurately as possible. Non-positive materials and / or positive connecting are particularly suitable, especially through precise clamping or adhesive bonding. Using a force-sensing element, the force can be determined based on the deformation of the foot receiving element.

[0009] According to a first preferred embodiment, the foot receiving element has: a body through which the foot receiving element is fastened to an inner tube; and two bearing pins protruding from opposite sides of the body. The body may be shaped to complement the inner contour of the inner tube, inserted into the inner tube from below, and preferably connected to the inner tube in a material-bonded manner. In the axial direction, at least the lower section of the inner tube overlaps with the body inserted therein, which increases the overall wall thickness in the area of ​​load introduced by the support foot. The bearing pins, for example, engage with the body. Particularly preferred embodiments are those in which the bearing pins and the body form a one-piece, integrated structural unit. The support foot is pivotally attached to the bearing pins.

[0010] According to a second alternative embodiment, the foot receiving element has a shaft tube that laterally protrudes beyond the inner tube, and the supporting foot is pivotally attached to the shaft tube. The shaft tube can be hollow or solid. The inner tube may have corresponding, aligned openings to receive the shaft tube. Alternatively, the shaft tube may be inserted into individual bearing sleeves that are securely connected to the inner tube and aligned with each other.

[0011] The bearing sleeve can be inserted into the opening in the inner tube or connected to the front end of the inner tube from below.

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

[0013] The force-measuring element can be pin-shaped and inserted into a complementary-shaped recess of the foot receiving element without clearance or under prestress.

[0014] A particularly useful embodiment is one in which the pin-shaped force-measuring element is a measuring pin and the recess is a measuring pin hole into which the measuring pin is inserted. The measuring pin should be understood as a sensor sensitive to force in the lateral direction, which is typically designed to be cylindrical and always inserted into a complementary-shaped measuring pin hole in the component to be measured with precise fit and / or under pretension or at least in the presence of an expected operating load. Pretensioning of the measuring pin is achieved, for example, by means of a clamping device integrated into the measuring pin. The diameter of the measuring pin hole is typically 6.00 mm to 10.00 mm, particularly preferably 8 mm.

[0015] According to a particularly useful embodiment, the measuring pin is mechanically clamped in the measuring pin hole. This allows the measuring pin to be removed from the measuring pin hole and reinserted for maintenance and repair purposes. If the connection is cast or glued within the measuring pin hole, replacing the measuring pin would require significantly more effort.

[0016] Advantageously, the recess is arranged in one of the bearing pins or the shaft tube. Both components directly absorb the force transmitted by the support legs and are therefore subject to shape changes under load, which are detected by the pin-shaped force-measuring element.

[0017] Advantageously, the recess is aligned axially with the bearing pin or shaft tube. This results in the advantage that the pin-shaped force-measuring element is exposed to bending stress on the bearing pin or shaft tube when the support leg is standing on the ground, and that particularly accurate measurement of the force acting on the support jack is possible. If the recess is eccentrically arranged on the central axis of the bearing pin or shaft tube, the measurement accuracy can be further improved on the side opposite to the outer and / or inner tube. In this region, the bearing pin or shaft tube experiences tension, the amount of which increases with increasing eccentricity, further enhancing measurement accuracy.

[0018] Conveniently, the recess is formed as a blind hole on one front side of the bearing pin or shaft tube. This makes it possible to position the pin-shaped force-measuring element in the region of maximum applied force without weakening the bearing pin or shaft tube through an unnecessarily long recess.

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

[0020] The support foot may have a base plate on which two wall segments are formed that project laterally relative to the inner tube. Bearing openings are formed in the wall segments to receive bearing pins or shaft tubes. At least one segment of a pin-shaped force-measuring element is arranged between the adjacent wall segments and the plane of the downward projection of the inner tube.

[0021] The flow of force originates from the support leg, through the wall section, to the bearing pin or shaft tube, and, if necessary, from there through the body to the inner tube. In the region between the wall section and the inner tube or its downward extension, the bearing pin or shaft tube, monitored by means of a pin-shaped force measuring element, experiences the greatest deformation, which allows for particularly accurate measurements by the pin-shaped force measuring element.

[0022] According to a further alternative embodiment, the force-measuring element is a strain gauge application. The strain gauge application is used to record the tensile and compressive deformation of the foot receiving element. Even with small deformation, the strain gauge application changes its resistance and acts as a strain sensor. Typically, the strain gauge application is glued to the foot receiving element, which deforms minimally under load. Thus, the deformation of the foot receiving element under load causes a change in the resistance of the strain gauge application.

[0023] Preferably, the strain gauge is attached to the upper and / or lower side of the body. This has the advantage that it eliminates the need for drilling or milling to weaken the foot receiving element, and the presence of expansion or compression on the upper and lower sides of the body allows for particularly accurate and reproducible measurements. Since the strain gauge is regularly positioned on the surface of the component to be monitored, it is preferably attached to the body, particularly the upper side, which is protected within the inner tube.

[0024] As an alternative to the above embodiments, strain gauges can be applied to shaft tubes to detect the deformation of the shaft tubes under load. Attached Figure Description

[0025] To better understand, the invention is explained in more detail below using six figures, which illustrate:

[0026] Figure 1 It is a longitudinal section view through the support jack, including the support legs mounted on it;

[0027] Figure 2 It is through the force-measuring element according to the first embodiment. Figure 1 A longitudinal section view of the lower section of the supporting jack rotated 90°;

[0028] Figure 3 It is based on Figure 1 Side view of the lower section supporting the jack;

[0029] Figure 4 It is a schematic longitudinal section view through the support jack with force measuring element according to the second embodiment;

[0030] Figure 5 It is a schematic longitudinal section view through a support jack with a force-measuring element according to the third embodiment; and

[0031] Figure 6 It is a schematic longitudinal section view through a support jack with a force-measuring element according to the fourth embodiment. Detailed Implementation

[0032] Figure 1 A longitudinal section view of the supporting jacks for the outer tube 20 having a square profile and the inner tube 30 therein, which is axially guided, is shown.

[0033] Due to the complementary profiles of the outer tube 20 and the inner tube 30, the inner tube 30 is held in the outer tube 20 in a rotationally fixed manner in the circumferential direction.

[0034] To attach the support jack to the vehicle, mounting flanges 23 protrude from both sides of the outer tube 20, with mounting holes 24 spaced at discrete intervals in the mounting flanges 23. The inner tube 30 carries a support foot 60 at its lower end, through which the support jack stands on the ground when the inner tube 30 is extended.

[0035] Arranged within the outer tube 20 is a gear arrangement 50, which has a main shaft 52 rotatably mounted relative to the outer tube 20 and a gear 51 rotatably fixed to the main shaft 52 at its upper end. By rotating the main shaft 52, the main shaft nut 31, securely inserted into the upper section 32a of the inner tube 30, moves downward or upward, depending on the direction of rotation. When the main shaft nut 31 moves downward, the inner tube 30 and the support foot 60 attached thereto are pushed towards the ground, and the support jack extends. When the main shaft nut 31 moves upward, the inner tube 30 and the support foot 60 are lifted together, and the support jack retracts.

[0036] The spindle 52 passes through a spindle bearing plate 21 arranged below the gear 51, wherein the spindle bearing plate 21 forms 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 supported 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 four sides. The spindle bearing plate 21 is oriented substantially orthogonal to the extension of the outer tube 20. The associated spindle opening 22 in the spindle bearing plate 21 and the spindle 52 are centrally received within the outer tube 20.

[0037] Figure 2 The lower section 32b of the inner tube 30 is shown, to which a support foot 60 is attached. The support foot 60 is pivotally mounted on a foot receiving element 40, which is stationarily fixed to the inner tube 30 in the region of the lower section 32b. In the exemplary embodiment shown, the foot receiving element 40 has a body 41 and two bearing pins 43 protruding on opposite sides of the inner tube 30. The bearing pins 43 protrude laterally outward below the inner tube 30 and / or the outer tube 20.

[0038] The main body 41 has a shape complementary to the inner contour of the inner tube 30, and is inserted into the inner tube 30 from below at its end face and permanently connected to the inner tube. At the maximum protruding position of the inner tube 30, the bearing pin 43 abuts against the end face of the outer tube 20. Typically, the main body 41 at least partially overlaps the inner tube 30 from the inside and protrudes downward from the inner tube.

[0039] The support foot 60 includes a generally flat base plate 61 on which two vertical wall segments 62 are formed. An inner tube 30 and an outer tube 20 are arranged between the two wall segments 62. Each wall segment 62 has mutually aligned bearing openings 63 through which a bearing pin 43 of the foot receiving element 40 extends. The bearing pin 43, located on the right side of the image plane, is a two-part construction for simplifying mounting of the support foot 60 to the foot receiving element 40 and has a removable assembly 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 swings about the central axis x of the bearing pin 43.

[0040] A recess 42 extending parallel to the central axis x is introduced into the front side 44 of one of the two bearing pins 43. This recess 42 may be, for example, a measuring pin hole 42.

[0041] In this exemplary embodiment, the recess 42 is designed as a blind hole 45, the deepest point 46 of which extends to a downwardly projecting plane y in the extension of the inner tube 30. A force-measuring element 10 in the form of a pin, particularly a measuring pin 11, is inserted statically into the recess 42 and clamped within the recess 42 relative to an associated bearing pin 43.

[0042] The pin-shaped force-measuring element 10 is located in the region between the nearest wall section 62 and the deepest borehole 46. When the inner tube 30 extends relative to the outer tube 20 and the support leg 60 stands on the ground, force flows from the support leg 60 through the bearing pin 43 to the inner tube 30. As a result, the bearing pin 43 between the wall section 62 and the body 41 is subjected to bending stress and undergoes relatively large deformation, which allows for accurate measurement by means of the pin-shaped force-measuring element 10, and the measured value can be attributed to the corresponding support load.

[0043] exist Figure 3 In the retracted position of the support jack, the lateral overlap of wall segment 62 with the outer tube 20 and the inner tube 30 is particularly noticeable. In the extended position of the support jack, wall segment 62 overlaps only with the inner tube 30.

[0044] Figure 2 and Figure 3Both show the eccentric orientation of the force-measuring element 10 within the bearing pin 43. Due to the bending stress under load, the force-measuring element 10 is located on the side of the bearing pin 43 facing the base plate 61, and it undergoes greater elongation with increasing eccentricity relative to the central axis x.

[0045] An intermediate coupling 13 is inserted into the open end of the recess 42, which closes the recess 42 to the outside, and through which only the connecting cable 14 is led out of the recess 42. The force-measuring element 10 is electrically connected to a vehicle-mounted network (not shown) via the connecting cable 14, from which power is supplied to the force-measuring element 10. Furthermore, the force-measuring element 10 provides a force-measuring signal to the vehicle via the connecting cable 14.

[0046] Figure 4 Alternative embodiments of the force-measuring element 10 in the form of a strain gauge application 12 are shown. Preferably, the strain gauge application 12 is applied to the upper side 41a of the body 41 and located in a protected position within the contour of the inner tube 30. In principle, it is also possible to attach the strain gauge application 12 to the lower side 41b of the body 41; however, it would be exposed to considerable environmental influences during operation.

[0047] The strain gauge application 12 can be connected to the vehicle's energy and data system (not shown here) via a connecting cable 14.

[0048] Figure 5 A further embodiment of the support jack is shown, in which the foot receiving element 40 includes a shaft tube 47. The shaft tube 47 is a continuous assembly having a circular cross-section. The shaft tube 47 passes beneath the opposing wall section of the inner tube 30, to such an extent that the bearing opening 63 of the wall section 62 is also penetrated by the shaft tube 47. The support foot 60 is pivotally mounted on the shaft tube 47.

[0049] To reinforce the lower section 32b of the inner tube 30 and to reduce surface pressure in that area, bearing sleeves 48 are securely attached to the inner tube 30 with their alignment aligned with each other, through which the shaft tube 47 passes. The axial alignment of the two bearing sleeves 48 is substantially perpendicular to the axial extension of the inner tube 30.

[0050] A force-measuring element 10 in the form of a strain gauge application 12 is applied to the surface of the shaft tube 47. In this exemplary embodiment, the strain gauge application 12 is located on the side of the shaft tube 47 facing the base plate 61 of the support foot 60. Particularly preferred is that the strain gauge application 12 is arranged between the wall sections of the inner tube 30, particularly between two spaced-apart bearing sleeves 48.

[0051] Figure 6A further exemplary embodiment of the invention is shown, comprising a foot receiving element 40 in the form of a shaft tube 47, the wall of which is thick enough to provide a recess 42 therein, particularly a measuring pin hole 42. A pin-shaped force-measuring element 10, particularly a measuring pin 11, is inserted into the recess 42 and releasably clamped therein. The recess 42 is located on the side of the shaft tube 47 facing the base plate 61.

[0052] Furthermore, the recess 42, also designed as a blind hole 45, opens at the front side 44 of the shaft tube 47 and terminates at its deepest point 46, overlapping with the adjacent bearing sleeve 48. In this respect, in this exemplary embodiment, at least a segment of the pin-shaped force-measuring element 10 is located between the wall segment 62 of the support leg 60 and the projection plane y in the extension of the inner tube 30.

[0053] List of reference numerals

[0054] 10 force measuring elements

[0055] 11. Pin-shaped force measuring element, measuring pin

[0056] 12 Strain Gauge Applications

[0057] 13. Transition coupling

[0058] 14 Connecting cables

[0059] 20 outer tubes

[0060] 21 Spindle bearing plate

[0061] 22 Spindle opening in the spindle bearing plate

[0062] 23 Install flange plate

[0063] 24 mounting holes

[0064] 30 Inner Tube

[0065] 31 Spindle Nut

[0066] 32a Upper section of the inner tube

[0067] 32b Lower section of the inner tube

[0068] 40-pin receiving element

[0069] 41 Main Body

[0070] 41a Upper main body

[0071] 41b Lower main body

[0072] 42 Recess, Measuring pin hole

[0073] 43 Bearing pins

[0074] 43a Assembly end piece

[0075] 43b screw

[0076] 44 bearing pin / front side of shaft tube

[0077] 45 Blind Hole

[0078] 46 Deepest point of borehole

[0079] 47 Shaft tube

[0080] 48 Bearing sleeve for shaft tube

[0081] 50 Gear Arrangement

[0082] 51 Gears

[0083] 52 Spindle

[0084] 60 Supporting feet

[0085] 61 Base Plate

[0086] 62 wall segments

[0087] 63 Bearing opening

[0088] x Center axis bearing pin

[0089] The plane of y-projection

Claims

1. A supporting jack, comprising a supporting leg (60) and a force-measuring element (10), wherein, The support jack has an outer tube (20) and an inner tube (30) movably mounted in the outer tube, and the support foot (60) is pivotally fixed to the inner tube (30) by means of a foot receiving element (40). Its features are, The force measuring element (10) is attached to the foot receiving element (40).

2. The supporting jack according to claim 1, characterized in that, The force is determined by means of the force measuring element (10) based on the deformation of the foot receiving element (40).

3. The supporting jack according to claim 1 or 2, characterized in that, The foot receiving element (40) has: a body (41) through which the foot receiving element (40) is fastened to the inner tube (30); and two bearing pins (43) protruding on opposite sides of the body (41).

4. The supporting jack according to claim 3, characterized in that, The foot receiving element (40) has a shaft tube (47) that laterally protrudes beyond the inner tube (30) and the support foot (60) is pivotally attached to the shaft tube.

5. The supporting jack according to claim 4, characterized in that, The force measuring element (10) is attached to the body (41), or to one of the bearing pin (43) or the shaft tube (47).

6. The supporting jack according to claim 5, characterized in that, The force-measuring element (10) is pin-shaped and is inserted into a recess (42) of a complementary shape of the foot receiving element (40) without clearance or under prestress.

7. The supporting jack according to claim 6, characterized in that, The pin-shaped force measuring element (10) is a measuring pin (11), and the recess (42) is a measuring pin hole (42) for the measuring pin (11) to be inserted.

8. The supporting jack according to claim 6 or 7, characterized in that, The recess (42) is arranged in one of the bearing pin (43) or the shaft tube (47).

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

10. The supporting jack according to claim 8, characterized in that, The recess (42) is eccentrically arranged on the side opposite to the outer tube and / or inner tube (20, 30) relative to the central axis (x) of the bearing pin (43) or the shaft tube (47).

11. The supporting jack according to claim 8, characterized in that, The recess (42) is formed as a blind hole (45) on the front side (44) of the bearing pin (43) or the shaft tube (47).

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

13. The supporting jack according to claim 8, characterized in that, The support foot (60) has a base plate (61) with two wall segments (62) laterally projecting from the base plate relative to the inner tube (30), wherein a bearing opening (63) is formed in the wall segment (62) for receiving the bearing pin (43) or the shaft tube (47), and at least one segment of the pin-shaped force measuring element (10) is arranged between the adjacent wall segment (62) and the plane (y) of the downward projection of the inner tube (30).

14. The supporting jack according to claim 4, characterized in that, The force measuring element (10) is a strain gauge application (12).

15. The supporting jack according to claim 14, characterized in that, The strain gauge application (12) is applied to the upper and / or lower sides (41a, 41b) of the body (41).

16. The supporting jack according to claim 14, characterized in that, The strain gauge application (12) is applied to the shaft tube (47).

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