Disengagement device and method

Abstract

Release device (1) for releasing an object suspended therefrom under load, in particular for drop tests, wherein the release device (1) comprises the following: • two complementary shaped clamping jaws (3a, 3b), wherein the clamping jaws (3a, 3b) are each rotatably mounted about a bearing (2), wherein the clamping jaws (3a, 3b) are arranged to hold a release bolt (4) with the suspended object attached thereto in the closed state; and • a toggle lever with two legs (5, 6), wherein the legs are connected at their common connection to a bearing bolt (7) and at their respective outer connections (22a, 22b) are connected to the clamping jaws (3a, 3b), wherein the toggle lever is configured to hold the clamping jaws (3a, 3b) closed without actuating force in an overextended configuration against a mechanical stop (10); wherein the toggle lever is configured to release the locking of the clamping jaws (3a, 3b) by a primary stroke (24) of the bearing bolt (7) from the overextension of the toggle lever beyond the dead center, corresponding to a secondary stroke (25), so that the clamping jaws (3a, 3b) move into an open state and the suspended object is dropped, wherein the stop (10) has a bolt with an eccentric cross-section so that the actuating force for unlocking the clamping jaws can be applied by rotating the bolt.

Description

[0001] The invention relates to a release device for releasing a suspended object under load and a method for releasing a suspended object under load. Such release devices and methods are used particularly in drop tests, as well as for releasing the test specimen in acceleration crash and shock tests.

[0002] The release device, sometimes also called the trigger device, suspends an object, for example, one to be subjected to a drop test, by means of an eyelet, rope, hook, or similar device. The object can be any type of test item, such as drop weights, vehicles, containers, or bins of any mass.

[0003] In conventional release devices, where the load is suspended from a single lever of the release mechanism that pivots laterally or at a specific angle, strong frictional forces are generated that must be overcome to release the load. Such a release device is described, for example, in DE 1 180 917 B. Additionally, the load is moved horizontally and does not fall precisely vertically, causing it to fall, for example, onto an edge instead of flat on the ground as desired. Other known release devices involve pulling a bolt or other profile laterally; these also generate high frictional forces and wear, as well as lateral movement of the object being released.

[0004] (D1) WO 96 / 31429A1 does contain clamping jaws (4') and a toggle lever (25). The strokes of the toggle lever (25) are large here, meaning that large release forces and travels are required. The clamping jaws can be adjusted according to the illustration in Fig. 6. Do not open. After the Fig. 5. The clamping jaws (4') are not fully opened, the space for the release bolt (6) Fig. 4 is severely restricted by the regulating part (7') and unfavorably shaped due to the sharp edges. Precise guidance of the toggle lever (25) is not possible in the Fig. 5-7 not visible. A release actuator etc. is not shown. The springs (34) support the clamping jaws (4'). Fig. 5 when opening and when closing and securing, Fig. 6, in the illustrated state and when the toggle lever (25; 28) rests against the housing (32), the clamping jaws (4') are slightly open, which should not be the case. The clamping jaws (4') must normally be closed when the toggle lever (25) is in a horizontal position. In the Fig. 5 and Fig. In the form shown in section 6, a trigger actuator (33) cannot be accommodated. Fig. 4. The shape of the clamping jaw contact surfaces is not adapted to the shape of the release bolt (6), which can jam, slip sideways, and has high friction. The release actuator (33), not shown, in the Fig. 5 and Fig. The release bolt (6) must exert considerable force and travel distances; it must have a small diameter and can become entangled and damaged by the edges of the clamping jaws (4'). Since the release actuator (33) is not shown, it cannot be determined whether it can fully open the clamping jaws. Complete opening is also impossible due to the regulating element (7'), the lower end stop of the toggle joint (28), and the dimensions of the housing (2'). The weaknesses mentioned previously in the representations of WO 96 / 31429A1 are not present in the application with its 16 claims. The notching device applied for is thus significantly more advanced than those previously known. However, claims 14 and 15 are known and not novel.

[0005] (D2) US 2009 / 0314 197 A1

[0006] The guide rod 8 with center bearing 18 and bearing housing 11 in the present patent application guides the toggle lever 5; 6 precisely so that the clamping jaws move synchronously and can also be closed by the existing spring. In US 2009 / 0314 197 A1, only the release cylinder (p) is capable of pivoting, which performs other functions. This has the disadvantage that the clamping jaws (a, d, e) can also pivot to the left and right shortly after the release process.

[0007] In the present patent application, the adaptation of the clamping jaw supports to the shape of the release bolt refers to full contact with minimal play of the release bolt against the curves of the clamping jaws, as in the Fig. 1 / 2 / 4 / 5 / 6a and 7 shown. Slanted supports as in US 2009 / 0314 197 A1 Fig. Number 1 were deliberately not considered because they generate high and uneven friction.

[0008] The locking bolt (J) with compression spring does hold the lever (k) securely when the clamping jaws are closed, but it is not secure enough because an unintentional stroke of the release cylinder (p) would trigger the load (W). This is prevented in the present application.

[0009] (D3) US 6 654 990 B2

[0010] A manually operated pin (36) secures a release lever (14). The pin may need to be removed from a great height before release.

[0011] In comparison, the locking bolt 16 in the present application provides a third safety feature in addition to the locking mechanism provided by the toggle lever, which is lowered by 1.5 mm in the middle and is reinforced by the load, and the vertical force exerted by the spring. Furthermore, the locking bolt 16 is remotely unlocked at any height immediately before release by a solenoid; the release device applied for here is therefore considerably safer than that of D3.

[0012] (D4) DE 10 2017 130 067 A1

[0013] The locking device (17) consists of a solenoid that extends and retracts the release pin (18) which blocks the release lever (5), possibly under tension.

[0014] In the present patent application, one or two electrically driven and remotely controlled actuators 14 are provided for releasing the load, although other actuators (hydraulic, pneumatic, mechanical) can also be used. The actuators are not required for safety purposes here, as a triple locking mechanism for the toggle lever 5; 6 is already in place.

[0015] Other methods involve breaking a rod or tab by applying force, for example using a hydraulic cylinder or a cutting device. This is very time-consuming, not very safe, and the broken piece must then be replaced.

[0016] In general, release devices that rely on friction to connect to the load are not safe, as the coefficient of friction can change rapidly due to contact with oil, grease, or similar substances. Under hydraulic pressure, oil can leak out and cause premature release.

[0017] Triggering via magnets can be suitable for smaller masses, but is also unreliable because a mechanical locking mechanism is required. Furthermore, a ferromagnetic counter plate with a polished surface must be present on the test specimen for the magnet, which distorts its mass.

[0018] Therefore, there is a need for release devices that allow the load to slide smoothly out of the release mechanism, ensuring a precise vertical fall without lateral movement upon release. Furthermore, it is desirable that only minimal forces are required for release, thus minimizing power consumption and extending service life. Rapid succession of releases should also be possible, and the release mechanism should be redundantly secured against premature release. A wider operating range, enabling the release of objects with masses from approximately 5 kg to 65,000 kg, would also be advantageous.

[0019] Against this background, the object of the invention is to provide a release device for releasing a suspended object under load, which addresses the aforementioned needs and, in particular, enables the release of the clamping jaws in a simple and convenient manner. A further object of the invention is to provide a method for releasing a suspended object under load.

[0020] According to the invention, this problem is solved with regard to the disengagement device by the subject matter of claim 1 and with regard to the method by the subject matter of claim 11.

[0021] The invention is based on the concept of a release device for releasing a suspended object under load, particularly for drop tests, comprising two complementary clamping jaws. The term "under load" means that, prior to release, the entire weight of the object rests on the clamping jaws holding it. Each clamping jaw is rotatably mounted about a bearing. In the closed position, the clamping jaws are designed to hold a release bolt with the suspended object attached to it. The clamping jaws can have various shapes; ideally, they have contact surfaces adapted to the shape of the release bolt to ensure low-friction release. The release bolt itself is not part of the release device but can be part of the object or of a suspension system for hanging the object.

[0022] The release device according to the invention further comprises a toggle lever with two legs. The two legs have a common connection and two outer connections, wherein the legs are connected at their common connection to a bearing pin and at their respective outer connections to the clamping jaws.

[0023] The toggle lever is designed to hold the clamping jaws closed in an overextended position against a mechanical stop, without requiring any actuation force. To release the object, the toggle lever is configured to release the clamping jaws through a primary stroke of the pivot pin, which moves the toggle lever beyond its dead center position. The movement to unlock the clamping jaws corresponds to a secondary stroke. In other words, the secondary stroke moves the clamping jaws into an open position, and the suspended object is released.

[0024] The primary stroke is generally larger than the secondary stroke; in particular, the primary stroke is much larger than the secondary stroke. Specifically, the primary stroke is at least a factor of 4, and more specifically, at least a factor of 7, larger than the secondary stroke.

[0025] As is well known, the special feature of the toggle lever principle is that the transmission ratio between applied actuating force and resulting force changes continuously during movement. In the bent state, the toggle lever provides a high travel speed with a low force transmission. The closer the toggle lever approaches the extended state, the more the stroke speed decreases at a constant actuating speed, while the pressing force increases. At the fully extended toggle lever – i.e., at dead center – the force theoretically approaches infinity. This means that the highest force transmission occurs in the last few millimeters of the toggle lever's travel. By overextending the toggle lever – beyond dead center – a locking effect can be achieved if a mechanical stop is present.In this state, the clamping force is maintained and the clamped workpiece cannot release itself, even without the application of an actuating force.

[0026] The design of the toggle lever, which in an overextended configuration keeps the clamping jaws closed against a mechanical stop without an actuating force, already represents a first safety measure against premature or unintentional triggering of the object.

[0027] The release device according to the invention is universally applicable, for example, freely suspended from a crane, guided via rollers or sliding bearings on drop systems, or permanently installed at various angles. No work is required on the release device after the load has been engaged; upon reaching the drop height, the device can be unlocked and released, for example, using a remote control.

[0028] It is particularly preferred that, after the primary stroke releases the locking mechanism of the clamping jaws, the weight of the object triggers a complete opening of the clamping jaws until the release bolt passes through. In other words, the secondary stroke is essentially caused by the mass of the object itself, and thus the release bolt slides out of the clamping jaws with minimal friction.

[0029] In particular, the bearing pin can be connected to a guide rod through which the actuating force for the primary stroke is transmitted. The guide rod can be guided in a pivotable bearing housing. Additionally, the bearing pin can be guided externally by cover plates so that it can only slide vertically up and down, resulting in synchronous movement of the two clamping jaws.

[0030] In one embodiment, the guide rod can contain a compression spring that additionally preloads the toggle lever in the extended configuration. In particular, the compression spring can press the toggle lever against the mechanical stop. This advantageously serves to further secure the clamping jaws in the closed position. In other words, when the release device is at rest, the toggle lever rests against the mechanical stop, for example 1.5 mm below the horizontal position, i.e., the dead center, due to its own weight and the spring force of the compression spring.

[0031] In one embodiment, the guide rod can be connected to at least one actuator via a yoke, the actuator being configured to apply the actuating force for the primary stroke. The actuator can be electrically operated. For symmetrical guidance and redundant safeguarding of the actuation, two electrically operated actuators can be provided. The primary stroke or release stroke can also be generated by other lifting or rotary elements and arrangements, as well as manually.

[0032] In one embodiment, a locking bolt can fix at least one leg of the toggle lever in the extended configuration. This advantageously serves to additionally secure the clamping jaws in the closed position. To release the object, the locking bolt can be pulled out by means of a small solenoid or manually via a rope, and then the guide rod can be actuated, for example, by the electric actuators, so that the primary stroke can be applied and the clamping jaws unlocked.

[0033] According to the invention, the stop has a bolt with an eccentric cross-section, or the stop can be implemented by a bolt with an eccentric cross-section. The actuating force for unlocking the clamping jaws can be applied by rotating the bolt. An eccentricity of just a few millimeters is sufficient to unlock the clamping jaws and thus release the object. The clamping jaws can then be opened and closed manually in the unloaded state. The overall height of the release device is thereby reduced by more than half compared to the embodiment with a guide rod, yoke, and actuators.

[0034] In a method according to the invention for releasing a suspended object under load, particularly for drop tests, the object is held in the closed position between two complementarily shaped clamping jaws by means of a release bolt attached to it. The clamping jaws are each rotatably mounted about a bearing. A toggle lever with two arms, the arms of which are connected at their common connection to a bearing bolt and at their respective outer connections to the clamping jaws, holds the clamping jaws closed in an overextended configuration against a mechanical stop without any actuating force. The method according to the invention comprises the following steps: releasing the locking mechanism of the clamping jaws by a primary stroke of the bearing bolt from the overextension of the toggle lever beyond its dead center, and the transition of the clamping jaws to an open position, so that the suspended object is dropped.The transition of the clamping jaws to the open position corresponds to a secondary stroke. The primary stroke is generally greater than the secondary stroke. In other words, the object can be released with a small primary stroke and minimal force. In particular, the primary stroke can be only a few millimeters. It is especially preferred that the primary stroke—measured from the dead center—is only a few hundred micrometers.

[0035] The primary stroke at the trigger point is greater than the secondary stroke, in particular the primary stroke is greater than the secondary stroke by at least a factor of 4, in particular by at least a factor of 7.

[0036] It is particularly preferred if, in the process, after the primary stroke releases the locking mechanism of the clamping jaws, the weight of the object triggers the complete opening of the clamping jaws until the release bolt passes through. In other words, the release after the primary stroke of 1.6 mm occurs "automatically".

[0037] In particular, the toggle lever in the overextended configuration can be pre-tensioned by a compression spring. This serves to additionally secure the clamping jaws in the closed position.

[0038] In one embodiment of the method, the actuating force for the primary stroke is applied by an actuator. This eliminates the need for manual work on the release device after the load has been engaged; once the drop height is reached, the device can be unlocked and released, for example, using a remote control.

[0039] In a further embodiment of the method, a locking bolt is released before the actuator applies the actuating force for the primary stroke. This provides an additional safety measure for the clamping jaws in the closed position.

[0040] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings. These show: Fig. 1 a schematic representation of a notching device according to the invention in a preferred embodiment with closed clamping jaws; Fig. 2 a schematic representation of a notching device according to the invention in a preferred embodiment with open clamping jaws; Fig. 3 a cross-sectional view along the in Fig. 1 listed markings AA; Fig. 4 a schematic representation of an embodiment of the clamping jaws; Fig. 5 a schematic representation of another embodiment of the clamping jaws; Fig. 6a a schematic representation of another embodiment of the clamping jaws; Fig. 6b a bottom view of the embodiment from Fig. 6a; Fig. 7 a schematic representation of another embodiment of the clamping jaws; Fig. 8 a schematic side view of a notching device according to the invention in a preferred embodiment;

[0041] Fig. Figure 1 shows a release device 1 according to the invention with closed clamping jaws 3a, 3b according to a preferred embodiment. The two clamping jaws 3a, 3b have a special shape that is adapted to the shape of the release bolt 4. In this example, a precisely round opening of, for example, 80 mm in diameter is formed at the lower end between the closed clamping jaws, which serves to receive a release bolt 4, which is generally connected to the part to be released (container, vehicle, etc.) via a cable suspension or a fixed articulated connection.

[0042] At the upper end, the clamping jaws 3a and 3b are connected by means of the legs 5 and 6, which have a common bearing pin 7 in the middle. The legs 5 and 6 form a toggle lever that can bend upwards and downwards from the horizontal position. The bearing pin 7 in the middle of the toggle lever accommodates a vertical guide rod 8, which contains a compression spring 9. The slightly pre-tensioned compression spring pushes the toggle lever 5, 6 downwards until, depending on the selected position, it rests on the support pin 10 0.5 to approximately 1.5 mm below the horizontal position, the dead center (travel S). The two legs 5 and 6 are connected to the clamping jaws 3a and 3b at their respective outer connections 22a and 22b.

[0043] The key point regarding the toggle lever and release mechanism is that the self-locking toggle lever, which is located approximately 1.5 mm below the horizontal position in the middle before release, must be lifted with minimal force by approximately 0.1 mm above the horizontal position, for a total of 1.6 mm. During this movement, the clamping jaws on the release bolt open almost imperceptibly by only about 0.014 mm. Release then occurs automatically, almost effortlessly and smoothly, due to the mass of the test specimen and the opening of the clamping jaws by the release bolt.

[0044] The guide rod 8 passes through a stationary but pivotable bearing housing 11 at the top, and a guide head 12 with lateral bolts 17 is screwed into the upper end. The guide head 12, the guide rod 8, and the toggle lever can move freely vertically within a yoke 13, to which the two electric actuators 14, 14' are articulated, without the actuators 14, 14' needing to move themselves. Release occurs automatically when the toggle lever is lifted approximately 0.1 to 0.2 mm above its horizontal position in the middle, i.e., when it rests on the support bolt 10. Depending on the distance S, it only needs to be lifted 0.6 to 1.6 mm by the electric actuators 14, 14'. The remaining stroke is only required to fully open the clamping jaws.

[0045] In other words, the actuators 14, 14' only extend upwards by approximately 1.6 mm to release the load, so that the toggle lever 5, 6 is approximately 0.1 mm above the horizontal or extended position at its central bearing pin 7. The clamping jaws 3a, 3b open by 0.014 mm. The actuators 14, 14' do not need to extend further, as the slight upward movement of the toggle lever 5, 6 by 0.1 mm is sufficient for the load, or rather the associated release pin 4, to automatically open the clamping jaws 14, 14' fully with minimal force, causing the load to fall downwards. The ratio of primary stroke 24 to secondary stroke 25 would be 1.6 mm to 0.014 mm in this example. The total usable stroke of the actuators 14, 14' of 103 mm serves only to fully open and close the clamping jaws 3a, 3b by approximately 85 mm without load, whereby the primary and secondary strokes approach each other at 103 mm and 83 mm, respectively.While the release bolt 4 opens the clamping jaws 3a, 3b, the process is reversed: here, the secondary stroke 25 causes a primary stroke 24. However, the actuators 14, 14' play no role here; they remain at a stroke of 1.6 mm unless they extend further after release, which takes approximately 1 second. This extension would immediately reopen the clamping jaws 3a, 3b, allowing the release bolt 4 to be engaged for the next drop test. The preferred procedure is as follows: When the load is released, the actuators are fully extended upwards beyond the required stroke of 1.6 mm (approximately 103 mm). The clamping jaws are then fully open, and if necessary, the load can be re-engaged on the ground. The clamping jaws are then closed by fully retracting the actuators, and the release device 1 is raised again for the next drop, which is normally done using a cable crane. The guide rod 8 can be moved unhindered by approximately 1.6 mm after lifting the folding lever 5, 6.The lever travels 103 mm upwards through the bearing housing 8 and is guided on both sides by the bolts 17 in a groove in the yoke 13, without affecting the actuators 14, 14'. The distance from the horizontal position of the toggle lever 5, 6 to the stop 10 was chosen to be 1.5 mm to ensure that the toggle lever is sufficiently secured against buckling upwards and that the force required to release the actuators is not too great.

[0046] The extendable locking bolt 16 serves as an additional safety device by preventing the toggle lever 5, 6 from folding upwards. Spacers 19 fix the release device 1 between two cover plates (see Fig. 8).

[0047] The release device can be connected to a hoist via bore 30. The release device can be used in any position, freely movable, guided on a column, or stationary.

[0048] An object (not shown) to be subjected to a drop test is suspended between the clamping jaws 3a, 3b using a connecting element with the release bolt 4. For this purpose, either the release bolt 4 can be inserted laterally into the closed clamping jaws 3a, 3b, or the slightly opened clamping jaws 3a, 3b can be placed onto the fixed release bolt 4. The weight of the release device then opens the clamping jaws 3a, 3b, which close again after locking into place. The electric actuators 14, 14' must then be fully retracted. Alternatively, the clamping jaws 3a, 3b can be fully opened by the electric actuators 14, 14' and closed after the release bolt 4 has engaged.

[0049] When the clamping jaws 3a, 3b are closed, the toggle lever 5, 6 is automatically pressed against the support bolt 10 by its own weight and additionally by the spring 9. The attached load (“test specimen”, not shown) also presses the toggle lever 5, 6 downwards, thus securing it multiple times and preventing accidental release. For further redundancy, the locking bolt 16 is retracted above the toggle lever 5, 6, preventing it from moving upwards. The release device 1 with the attached load is then typically raised to the required height using a crane or other lifting equipment. The locking bolt 16 is then pulled out using a small lifting magnet or manually via a rope (not shown). Subsequently, the electric actuators 14, 14' are extended, for example, by approximately 1.6 mm to release the load.

[0050] Fig. Figure 2 shows the release device 1 according to a preferred embodiment with open clamping jaws 3a, 3b after the locking of the clamping jaws 3a, 3b has been released by the primary stroke, applied by the actuating force of the extended electric actuators 14, 14' and transmitted via the yoke 13, guide rod 8 and bearing bolt 7 to the toggle lever 5, 6. The complete opening of the clamping jaws 3a, 3b until the passage of the release bolt 4 is effected by the weight of the object to be released (not shown).

[0051] There is hardly any friction or wear on the support 20a, 20b or on the release bolt 4, because due to the small upward movement of the toggle lever, the friction path between support 20a, 20b and release bolt 4 is only about 0.01mm, after which the clamping jaws open almost without force.

[0052] Fig. Figure 3 shows a cross-sectional view along the in Fig. The markings AA shown in Figure 1. The legs 5 and 6 of the toggle lever are connected in the middle by means of bearing bolts 7 and guided by means of a center bearing 18 (with sliding block, sliding shoe). Screwed spacers 19 fix two cover plates 15a and 15b between which the bearing bolts 7 are connected and the center bearing 18 is attached.

[0053] Fig. Figure 4 illustrates the movement of the clamping jaws 3a, 3b, which are rotatably mounted about the bearings 2. The connections 22a, 22b are connected to the arms of the toggle lever. In an overextended configuration of the toggle lever at the mechanical stop 10, the clamping jaws 3a, 3b are closed. When the toggle lever is released from overextension by the primary stroke, the connections 22a, 22b move towards each other, as indicated by the arrows above. This opens the clamping jaws 3a, 3b, as indicated by the arrows below. The clamping jaws 3a, 3b are adapted here for a round release bolt 4.

[0054] Fig. Figure 5 shows an alternative embodiment of the clamping jaws 3a, 3b, which are adapted to a pear-shaped cross-section of the release bolt. In this embodiment, the release bolt slides particularly smoothly out of the clamping jaws 3a, 3b.

[0055] Fig. Figure 6a shows an alternative design of the clamping jaws 3a, 3b with a toothing in the lower area 21 of the clamping jaws 3a, 3b. Fig. Figure 6b shows a bottom view, illustrating the serrations in area 21 of the clamping jaws 3a, 3b along the Y direction. The serrations of the clamping jaws 3a, 3b slightly increase the contact area of ​​the release bolt, thus allowing for smaller dimensions of the clamping jaws 3a, 3b and the release bolt 4, which can be advantageous in some applications.

[0056] Fig. Figure 7 shows an alternative embodiment of the clamping jaws 3a, 3b, wherein several rollers 23 are attached in the area of ​​the bearing surface of the release bolt 4. The rollers 23 further reduce the already low friction during release by the release device 1 according to the invention, thus adapting the release device 1 according to the invention to precision releases of small masses, and thereby also making it possible to use smaller actuators.

[0057] Fig.Figure 8 shows a schematic side view of a notching device 1 according to the invention and its installation between cover plates 15a and 15b, which are spaced apart by spacers 19 and fixed with screws. The bearing pin 7 is guided by the central bearing 18 so that it can only slide vertically up and down, which is important for the synchronous movement of the two clamping jaws 3a, 3b. The guide rod 8 is surrounded by the compression spring 9 and supported in the bearing housing 11, to which the guide head 12 and yoke 13 are attached. The actuators are not shown for clarity. Reference symbol list 1 Release device 2 warehouses 3a, 3b clamping jaws 4 trigger bolts 5, 6 thighs 7 bearing bolts 8 Guide rod 9 compression spring 10 strikes 11 bearing housings 12 Guide head 13 yoke 14, 14' actuator 15a, 15b Cover plate 16 locking bolts 17 bolts 18 Central storage 19 spacer 20a, 20b Support surface Area 21 22a, 22b connection 23 rolls 24 Primary stroke 25 Secondary stroke 30 bore

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