Group of elements for the construction of a gas spring and respective safety system

Abstract

A gas spring (100) comprising a first fixed element (1) equipped with a side wall (11) and an abutment surface (12), a second hollow movable element (2), equipped with a side wall (21) and an upper closure element (22) delimiting a concavity and configured to slide outward from the side wall of the first element (1) to allow the spring (100) to pass from an extended configuration to a compressed configuration, a gasket (4) adapted to increase the tightness of said gas spring (100). The side wall (21) and the upper closure element (22) are two distinct elements, and the upper closure element (22) presents a shaped profile configured to go into abutment with the side wall (21) and to ensure the housing of the gasket (4) interposed between the side wall (21) and the upper closure element (22).

Description

[0001] GROUP OF ELEMENTS FOR THE CONSTRUCTION OF A GAS SPRING AND RESPECTIVE SAFETY SYSTEM DESCRIPTION

[0002] The present invention concerns a group of elements for the construction of a gas spring and a respective safety system.

[0003] Field of the invention

[0004] The invention falls within the technical field of industrial springs, in particular the technical field of the systems and elements constituting a gas spring having a safety function.

[0005] Prior Art

[0006] Gas springs normally include: a fixed body, called for example a cylinder; a movable component, also called rod; possibly guide means for the rod; one or more sealing elements; a component to introduce the gas inside the cylinder, also called loading valve.

[0007] Currently, among the aspects of greatest importance in this field there are those relating to the ease of production and to the safety of these mechanical devices.

[0008] In particular, an aspect of considerable importance is due to the processing quality and to the thickness of the internal walls of the gas springs as the smoother and more homogeneous the walls are, the better the gas spring will perform.

[0009] Furthermore, if it is possible to reduce the thickness of the walls of the aforementioned gas springs, it is possible to limit the quantity of material used to make the gas springs themselves.

[0010] It is not uncommon for the springs, once they are put into continuous operation, to suffer damage and deteriorate, as a result of a normal wear, or following use in service conditions which were improper or not taken into account in the design phase, but also due to completely fortuitous events.

[0011] An example of improper use is to subject the spring to extra stroke. By “extra stroke” we mean a stroke greater than that of the maximum one calculated in the design phase. In this case, impacts are created between the fixed parts and the movable parts of the spring. These impacts cause damage to both the spring and the equipment on which it is installed or used.

[0012] As is known, the improvement in the efficiency of the thrust elements in general has caused over time an increase in the maximum loads that can be supported by gas springs. This is almost always achieved thanks to an increase in the pressure of the gas inside the springs themselves.

[0013] The pressures that modern gas springs can tolerate reach initial values even greater than 180-200 bar, and must be duly taken into consideration by designers, production and / or maintenance staff, and by the user using them as part of its activities.

[0014] It is therefore necessary to avoid damage or deterioration to the springs themselves, and particular attention must be paid to those categories of damage that often affect a component, without however causing its immediate breakage.

[0015] For example, damage which is minor and / or not detectable through an immediate visual inspection does not allow a user to recognize a compromised gas spring, nor, at least, to implement precautionary measures, such as, for example, replacing the damaged part or disposing of the piece.

[0016] If we further consider that gas springs usually support cyclical loads, the definitive breakage of the compromised spring causes unpredictable and sudden accidents, in which regard the staff and operators in proximity of the breaking spring run quite serious risks. The consequences of such accidents can be very serious, causing injuries of varying degrees and even resulting in death.

[0017] Since the evolution of these phenomena is difficult to evaluate, there is a strong need in this field to ensure adequate safety conditions regardless of the technologies available to operators in this field to carry out checks of various kinds.

[0018] In the case of a spring that has been subject to an extra stroke condition, the collision between the movable parts and the fixed parts of the spring does not guarantee the complete release of gas.

[0019] For example, it is possible for a gas spring gasket to wear or break without an operator noticing from the outside.

[0020] In known solutions, when the spring is subject to an extra stroke condition, the gasket, even if damaged, would still remain very close to its seat, inside the spring, with the possibility of re-engaging. This would allow only a partial discharge of gas which could allow the spring to continue to operate despite the breakage, posing considerably high risks.

[0021] It is therefore of crucial importance to provide the gas springs with a secondary safety mechanism that can act in the event of a malfunction of the primary safety mechanisms, which can prevent a component breakage.

[0022] Aim of the invention

[0023] The aim of the present invention is therefore to provide a group of elements for the construction of a gas spring and a respective safety system capable of solving the above-mentioned drawbacks and critical issues.

[0024] Specifically, a first aim of the present invention is to construct a gas spring with a respective safety system which intervenes in the event of exceeding the maximum stroke limit expected for the gas spring itself.

[0025] In addition, another aim of the present invention is to ensure the release of gas from the spring in the event of a collision between its components and therefore in the event of its extra stroke.

[0026] A further aim of the present invention is to provide a gas spring with a respective safety system which is more easily produced and assembled.

[0027] Another aim of the present invention is to construct a gas spring which allows the gasket to come out and prevents its re-engaging.

[0028] These and other aims are achieved by a group of elements for the construction of a gas spring and a respective safety system according to the attached independent claim.

[0029] Further detailed technical features are mentioned in the attached dependent claims.

[0030] Object of the invention

[0031] The object of the invention is therefore a gas spring including a first fixed element equipped with a first side wall and an abutment surface, a second hollow movable element, equipped with a second side wall and an upper closure element delimiting a concavity and configured to slide outward from the first side wall of the first element to let said spring pass from an extended configuration to a compressed configuration, a gasket adapted to increase the tightness of said gas spring, wherein the second side wall and the upper closure element of the second element are two distinct elements and the upper closure element presents a shaped profile configured to go into abutment with the second side wall ensuring the housing of the gasket interposed between the second side wall and the upper closure element.

[0032] This advantageously makes it possible to reach the internal surface of the base wall and of the second side wall even in case of very deep springs, facilitating all the necessary processing.

[0033] According to the invention, the shaped profile of the upper closure element of the second element includes: a first portion equipped with a first diameter and a first surface facing outward from the spring and lying in a first horizontal plane, a second portion equipped with a second diameter and a second surface facing outward from the spring and lying in a second horizontal plane wherein this second diameter is greater than the first diameter, a third portion equipped with a third diameter and a third surface facing outward from the spring and lying in a third horizontal plane wherein this third diameter is greater than the first diameter and smaller than the second diameter and wherein the third surface is adapted to receive into abutment the second end of the side wall of the second element.

[0034] This configuration advantageously makes it possible to avoid a thread between the two elements, as pressure alone maintains the upper closure element in place.

[0035] In a preferred embodiment, the upper closure element of the second element presents a fourth portion equipped with a fourth diameter and a fourth surface facing outward from the spring and lying in a fourth horizontal plane, this fourth diameter is smaller than the third diameter of the base wall itself. This embodiment allows the abutment between the upper closure element and the side wall of the second element to be improved.

[0036] Again according to the invention, the side wall of the second element includes a first end intended to go into abutment with the abutment surface of the first element and a second end intended to go into abutment with the upper closure element of the second element; the second end of the side wall of the second element is inclined by approximately 90° relative to the side wall and projects toward the inside of the spring, this second end is adapted to maintain the upper closure element in place.

[0037] In this configuration, advantageously, the second side wall can be made easily and quickly, as it can be obtained from a tube. Again according to the invention, on the second element there is, defined by the second end, a through hole equipped with an internal diameter greater than or equal to the first diameter of the upper closure element so that the first portion of the upper closure element is able to pass through the through hole of the second element. This feature, linked to the fact that the second end of the second side wall defines this through hole, makes it possible to facilitate the detachment between the upper closure element and the side wall of the second element in case of necessity.

[0038] Furthermore, the internal diameter of the through hole of the second element is smaller than the third diameter of the third portion of the upper closure element of the second element, so as to create a space between the second end of the side wall and the second portion of the upper closure element in which the gasket can be housed.

[0039] This advantageously allows the tightness to be obtained in a strategic point of the spring, as the gasket would be in a position close to the gas outlet point when in dangerous conditions; from that position, once the tightness is lost following exceeding a maximum stroke limit, the gasket would be sucked in by the outgoing gas flow itself, and expelled by the spring.

[0040] Furthermore, still according to the invention, the second end of the side wall of the second element presents a thickness lower than the distance between the first surface and the third surface of the upper closure element of the second element itself, so that - when the spring is completely filled with gas - the first portion of the upper closure element projects at least partially from the second end of the second side wall. In this way, once the second side wall comes into abutment with the abutment surface of the first element, in the event of exceeding of the maximum stroke limit, the upper closure element moves relative to the second side wall and continues to lower, so that the outermost surface of the upper closure element and the outermost surface of the second end are coplanar. In such conditions, the tightness is advantageously lost, promoting the release of the gas and avoiding very dangerous accidents for operators and the equipment on which the springs themselves are installed.

[0041] Brief description of the figures

[0042] The present invention will now be described, by way of non-limiting example, according to some of its preferred embodiments, and with the aid of the attached figures, in which:

[0043] - Figure 1 is a sectional view of a gas spring including the safety system according to the invention;

[0044] - Figures 2A-2C show a detail of the gas spring while the sealing element is coming out from the gas spring of Figure 1A.

[0045] Detailed description

[0046] In the following, reference is made to a gas spring described by way of example in the patent document W02022054116A1 .

[0047] This does not mean that the invention cannot be applied to other types of gas springs with more simplified or in any case different configurations.

[0048] With reference to the figures mentioned, a preferred embodiment of a group of elements for the construction of a gas spring and a respective safety system according to the invention is represented.

[0049] With reference to Figure 1 , the gas spring according to the invention, indicated generically by 100, includes a hollow fixed body 1 or cylinder and a hollow movable body 2 or rod, having a concavity opposite to said cylinder 1 .

[0050] The rod 2 is configured to slide outward from the cylinder 1 , always remaining in contact, from an extended or open configuration to a compressed or closed configuration.

[0051] Advantageously, the cylinder 1 and the rod 2 include respective side walls and respective base walls or closure elements, as will be seen better below.

[0052] In particular, the cylinder 1 includes a side wall 11 and an end-of-stroke or abutment surface 12 perpendicular to the side wall 11 ; the rod 2 includes a respective side wall 21 and an upper closure element 22.

[0053] Advantageously, according to the present invention, the upper closure element 22 and the side wall 21 of the rod 2 are two distinct components so as to facilitate the production as well as to provide an additional safety system for the spring 100 as will be more clearly described in the following.

[0054] The upper closure element 22 is made so as to present a shaped profile configured to go into abutment with the side wall 21 and ensure the housing of a gasket between them.

[0055] In particular, the upper closure element 22 presents:

[0056] - a first portion 221 equipped with a first diameter and a first surface facing outward from the spring and lying in a first horizontal plane;

[0057] - a second portion 222 equipped with a second diameter and a second surface facing outward from the spring and lying in a second horizontal plane, the second diameter of the second portion 222 is greater than the first diameter;

[0058] - a third portion 223 equipped with a third diameter and a third surface facing outward from the spring and lying in a third horizontal plane, the third diameter of the third portion 223 is greater than the first diameter and smaller than the second diameter;

[0059] - a fourth portion 224 equipped with a fourth diameter and a fourth surface facing outward from the spring and lying in a fourth horizontal plane, the fourth diameter of the fourth portion 224 is smaller than the third diameter of the third portion 223.

[0060] The second portion 222 is positioned lower than the other portions 221 , 223 224 and is adapted to accommodate at least one gasket on the second surface.

[0061] In a second embodiment, the upper closure element 22 includes only a first, a second and a third portion.

[0062] The upper closure element 22 is maintained in place, ensuring a correct tightness, thanks to the pressure of the gas inside the spring 100 exerted on the internal surface of the upper closure element 22 itself and in such a way as to prevent said upper closure element 22 from de-coupling from said side surface 21.

[0063] In particular, this coupling is guaranteed by the gas pressure which exerts an upward force on the internal surface of the upper closure element 22, and a downward force exerted on the upper surface of a gasket fixed to the side wall 21 and placed in contact with the side surface 11 , and which is then transferred to the side wall 21 itself. The two forces have opposite directions and guarantee the coupling and tightness between the side wall 21 and the upper closure element 22.

[0064] The side wall 21 is perpendicular to the upper closure element 22 and includes a first end 211 intended to go into abutment with an abutment surface 12 of the cylinder 1 and a second end 212 intended to go into abutment with the upper closure element 22 itself of the rod 2.

[0065] In more detail, the second end 212 is inclined by approximately 90° relative to the side wall 21 and projects inward to maintain the upper closure element 22 in place when the gas is inside the spring 100.

[0066] More in detail, when the upper closure element 22 is correctly in place and abutting the side wall 21 , the third portion 223 of the upper closure element 22 is in contact with the second end 212 of the rod 2 by means of the gasket 4.

[0067] This gasket 4 guarantees the correct tightness of the spring 100, preventing the gas inside it from escaping from the portion of contact between the upper closure element 22 and the side wall 21 of the rod 2.

[0068] The internal diameter of the second end 212 is smaller than the third diameter of the third portion 223 of the upper closure element 22 so that the gasket 4 is placed between the second portion 222 of the upper closure element 22 and the second end 212 of the side wall 21 of the rod 2.

[0069] In particular, the gasket 4 is in contact at the bottom with the second portion 222 of the upper closure element 22, in contact at the top with the second end 212 of the side wall 21 and in contact, laterally, with the fourth portion 224 of the upper closure element 22.

[0070] Advantageously, this construction with two distinct elements allows an operator to carry out the assembly operations in a more convenient and fast way.

[0071] Furthermore, the construction with two elements also makes it possible to achieve advantages in the processing and production phase of the spring as it makes it possible to more easily reach the internal surface of the side wall 21 and of the upper closure element 22, to carry out the processing necessary to the proper operation of the spring 100, such as calibration or threading.

[0072] Preferably, as visible in Figure 1 , the side wall 11 and the base wall of the cylinder 1 can also be two distinct components fixed together.

[0073] The cylinder 1 and the rod 2 are made in such a way that the internal surface of the side wall 21 of the rod 2 can slide outward but in contact with the external surface of the side wall 11 of the cylinder 1 .

[0074] Operationally, when the spring 100 passes from the extended configuration to the compressed configuration, the rod 2 slides downward, reducing the internal volume of the spring 100 and consequently increasing the internal pressure of the gas inside the spring 100 itself.

[0075] When the rod 2 completes its stroke, reaching an end-of-stroke condition, the first end 211 of the side wall 21 goes into abutment with the abutment surface 12 of the cylinder 1 so as to prevent further downward movements of the rod 2.

[0076] In this situation, as shown in Figure 2A, the upper surface of the closure element 22 facing outward from the spring is at a higher height than the fifth horizontal plane defined by the second end 212 of the side wall 21.

[0077] In other words, the upper surface of the first portion 221 of the upper closure element 22 facing outward from the spring is maintained, thanks to the thrust of the gas inside the spring itself, at a higher height than the second end 212 of the side wall 21.

[0078] During the life of the spring, this passes from an extended position to a compressed position, wherein respectively the first end 211 of the side wall 21 is distant from the abutment surface 12 of the cylinder 1 , and the first end 211 of the side wall 21 is close to the abutment surface 12 of the cylinder 1 .

[0079] In the event that the spring is mistakenly brought to a position of extra stroke, wherein the first end 211 of the side wall 21 collides with the abutment surface 12 of the cylinder 1 , the side wall 21 will stop, while the upper closure element, constrained to this side wall only by the presence of gas inside the spring 100, will be free to continue its downward stroke in opposition to the thrust exerted by the gas itself.

[0080] As shown in Figure 2B, when the fourth portion 224 of the upper closure element 22 is at an equal or lower height of the internal surface of the second end 212 of the side wall 21 , the gasket 4 is no longer compressed between the two components 21 and 22 of the rod 2, and detaches from the respective surfaces allowing a partial release of gas from the spring 100.

[0081] Finally, when the upper surface of the first portion 221 of the upper closure element 22 is coplanar with the second end 212 of the side wall 21 , i.e. it is at the same height of the external surface of the second end 212 of the side wall 21 , as shown in Figure 2C, the upper closure element 22 is at no point in contact with the side wall 21 of the rod 2.

[0082] In this situation, the gasket 4, which has already lost its tightness in the previous phase, thanks to the pressure of the gas inside the spring 100, is pushed upwards by its flow and expelled from the spring 100 itself following the arrow indicated in Figure 2C.

[0083] Once the gasket 4 has come out, the tightness of the spring 100 is irreversibly and completely lost, so that the gas can be released completely, avoiding the reuse of the spring 100 and the occurrence of potential accidents.

[0084] In this way, an operator can immediately notice the breakage of the spring 100, thereby preventing the spring from being subjected to further processing and avoiding risky inspection operations which could lead to accidents or even serious injuries if the spring is compromised and still has gas under pressure inside.

[0085] In fact, in absence of internal pressure in the spring 100, the upper closure element 22 would be visibly de-coupled from the side wall 21 .

[0086] Still advantageously, the present invention allows the production of gas springs 100 of any size and greater ease of production, for example with the possibility of reducing the weight and a consequent material saving.

[0087] In particular, making the rod 2 with two distinct components allows the side wall 21 to be produced directly from a tube, unlike the current methods, which involve drilling a solid cylinder, with the consequent waste of material and risk of breakage of the components being processed inside it.

[0088] In fact, since in this embodiment shown in the figures the rod 2 is substantially similar to a hollow cylinder, a turning machine will be able to easily operate and shape both ends and the central portion of the rod 2.

[0089] Furthermore, it is possible to make a standard upper closure element 22 that can be used for a wide variety of springs 100, in combination with different lengths of the side wall 21.

[0090] From the above description, the features of the group of elements for the construction of a gas spring and the respective safety system, object of the invention, are clear, as well the advantages thereof.

[0091] Finally, it is clear that numerous other variations can be made to the device in question, without departing from the principles of novelty inherent in the inventive idea, just as it is clear that, in the practical implementation of the invention, the materials, shapes and size of the illustrated details may be any according to the requirements and they may be replaced with other equivalent ones.

[0092] Where the features and techniques mentioned in any claim are followed by reference signs, such reference signs have been included for the sole aim of increasing the intelligibility of the claims and, accordingly, such reference signs have no limiting effect on the interpretation of each element identified by way of example by these reference signs.

Claims

CLAIMS1. A gas spring (100) including a first fixed element (1 ) equipped with a first side wall (11 ); a second hollow movable element (2), equipped with a second side wall (21 ) and an upper closure element (22) delimiting a concavity and configured to slide outward from the first side wall (11 ) to let said spring (100) pass from an extended configuration to a compressed configuration; a gasket (4) adapted to increase the tightness of said gas spring (100), wherein said second side wall (21 ) and said upper closure element (22) of the second element (2) are two distinct elements and said upper closure element (22) presents a shaped profile configured to go into abutment with said second side wall (21 ) and to receive said gasket (4) in a housing interposed between said second side wall (21 ) and said upper closure element (22), said gas spring (100) being characterized in that said shaped profile includes a first portion (221 ) equipped with a first diameter and a first surface facing outward from the spring and lying in a first horizontal plane; a second portion (222) equipped with a second diameter and a second surface facing outward from the spring and lying in a second horizontal plane, the second diameter being greater than said first diameter; a third portion (223) equipped with a third diameter and a third surface facing outward from the spring and lying in a third horizontal plane, the third diameter being greater than said first diameter and smaller than said second diameter, the third surface being adapted to receive in abutment the second end (212) of said second side wall (21 ).

2. The gas spring (100) according to claim 1 characterized in that said upper closure element (22) has a fourth portion (224) equipped with a fourth diameter and a fourth surface facing outward from the spring and lying in a fourth horizontal plane, the fourth diameter being smaller than said third diameter.

3. The gas spring (100) according to claim 1 or 2 characterized in that said second side wall (21 ) of said second element (2) includes a first end (211 ) intended to go into abutment with an abutment surface (12) associated with said first element (1 ) and a second end (212) intended to go into abutment with said upper closureelement (22) of said second element (2) and in that said second end (212) is inclined of approximately 90° relative to the side wall (21 ) and projects toward the inside of the spring, being adapted to maintain said upper closure element (22) in place.

4. The gas spring (100) according to claim 3 characterized in that said second element (2) presents a through hole equipped with a fifth internal diameter greater than or equal to the first diameter of the upper closure element (22), so that the first portion (221 ) of the base wall is able to pass through said through hole, the through hole being defined by said second end (212).

5. The gas spring (100) according to claim 4 characterized in that said fifth internal diameter is smaller than the third diameter, so as to create a space between the second end (212) and the second portion (222) of the upper closure element (22), adapted to house said gasket (4).

6. The gas spring (100) according to one of claims 3-5 characterized in that said second end (212) presents a thickness lower than the distance between the first surface and the third surface of the upper closure element (22).

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