Low-friction gas spring for dies or molds

Abstract

The invention concerns a gas spring (10) comprising a fixed body (1); a movable body (2); sealing means (3) to contain a first fluid (4) within the spring (10), so as to transition from a first extended configuration wherein the first fluid (4) is expanded to a second contracted configuration wherein the first fluid (4) is compressed by the movable body (2). According to the invention, the sealing means comprise a membrane (3) adapted to contain the first fluid (4).

Description

[0001] LOW-FRICTION GAS SPRING FOR DIES OR MOLDS

[0002] *****

[0003] The present invention concerns a low-friction gas spring for dies or molds.

[0004] Field of the invention

[0005] The invention falls within the technical field of industrial springs for dies or molds, in particular within the technical field of systems and elements forming an industrial gas spring adapted to achieve high speeds without compromising safety.

[0006] In particular, it is a gas spring, wherein the friction of the gaskets, which increases their temperature during use, thereby deteriorating them in a relatively short time, is eliminated through the use of a flexible sealing element.

[0007] In the following, the description will be addressed to a gas spring, but it is clear that the same should not be considered limited to this specific use.

[0008] Prior art

[0009] The currently known gas springs comprise: a fixed body, referred to, for example, as a cylinder; a movable component, also referred to as a rod; possibly, guiding means for the rod; one or more sealing elements; a component for introducing gas into the cylinder, also referred to as a charging valve.

[0010] Currently, in the known springs, the speed of the cycles is limited by the gasket, which overheats and deteriorates quickly. Furthermore, the heat generated causes the gas contained in the spring to expand, which in turn increases the pressure and the active stress on the gasket.

[0011] Some known solutions provide for discharging the spring and / or reducing the stroke, possibly increasing the volume, so as to reduce the stress on the gasket.

[0012] Of course, this results in an increase in the overall volume of the spring, making it less efficient in terms of its overall dimensions.

[0013] Aim of the invention

[0014] The main objective of the present invention is to provide a gas spring that overcomes the aforementioned drawbacks and, in particular, easily and immediately eliminates the problem of overheating of the sealing means.

[0015] In detail, the objective of the invention is to produce a low-friction gas spring.

[0016] Another objective of the present invention is to produce a gas spring that allows the achievement of a high cycle speed without compromising its long-term reliability.

[0017] Object of the invention

[0018] Therefore, the object of the invention is a gas spring comprising a fixed body, a movable component, and sealing means to contain a first fluid, for example a gas, within the spring, so as to transition from a first extended configuration, wherein the first fluid is expanded, to a second contracted configuration, wherein the first fluid is compressed between the movable component and the fixed body.

[0019] According to the invention, the sealing means comprise a membrane adapted to contain the first fluid, thereby advantageously eliminating the presence of gaskets. Furthermore, according to the invention, the membrane can be fixed within the fixed body along a fastening line, so as to create a sealed chamber containing the first fluid, having a flexible wall comprising the membrane and the other walls corresponding to the internal walls of the fixed body.

[0020] Preferably, the fixed body can comprise a first component adapted to contain the first fluid, and a second component adapted to partially receive and to couple with the movable component; also preferably, the fastening line can be formed at the junction of the first component with the second component.

[0021] In this way, advantageously, the membrane is easily coupled with the fixed body, during the assembly steps of the spring itself.

[0022] Furthermore, according to the invention, it is possible to provide a second fluid, external to the first membrane, adapted to distribute the compressive force exerted by the movable component on the first fluid.

[0023] In this case, advantageously, it is also possible to provide a second membrane adapted to contain the second fluid. This increases the efficiency and reliability of the spring as a whole.

[0024] Furthermore, still in such cases, a third fluid can be provided between the first membrane and the second membrane.

[0025] This advantageously allows a better distribution of the forces on the membranes.

[0026] For example, according to the invention, the third fluid can be an oil, and it is possible to provide calibrated ducts between the fixed body and the movable component through which the oil can flow, so as to determine the reciprocal movement speed between the fixed body and the movable component.

[0027] In fact, by knowing the viscosity of the oil, the conditions of the spring when it will be operative, and the maximum desired speed, it is possible to determine the dimensions of the ducts and make the oil act as a braking element.

[0028] Moreover, alternatively, the first membrane and / or the second membrane can be hollow and contain the chamber of the first fluid and / or the second fluid.

[0029] This allows the membrane with the gas to be positioned during the assembly of the spring without the need for charging valves.

[0030] Still according to the invention, end stops can be provided to limit the travel of the movable component and avoid damage to the membrane.

[0031] In particular, according to the invention, the membrane can be of the non-elastic type.

[0032] Brief description of the figures

[0033] The present invention will now be described, by way of example and not limitation, according to some of its preferred embodiments, and with the aid of the attached figures, wherein:

[0034] Figure 1 is a sectional view of the spring of the invention, in a first configuration;

[0035] Figure 2 is a sectional view of the spring shown in Figure 1 , in a second configuration;

[0036] Figure 3 is a sectional view of a first variant of the spring of the invention;

[0037] Figure 4 is a sectional view of a second variant of the spring of the invention;

[0038] Figure 5 is a sectional view of a third variant of the invention;

[0039] Figure 6 is a sectional view of a fourth variant of the invention;

[0040] Figure 7 is a sectional view of a fifth variant of the invention.

[0041] Detailed description

[0042] In the various figures, similar parts will be indicated by the same numerical references.

[0043] With reference to Figures 1 -4, a gas spring 10 is shown, comprising a cylinder 1 , a rod 2, and sealing means 3 to contain the gas 4 within the cylinder 1 . The gas spring 10 transitions from an extended configuration (Figure 1 ), wherein the rod 2 is outside the cylinder, except for the head portion 5, to a compressed configuration (Figure 2), wherein the rod 2 compresses the gas 4 through the head 5.

[0044] The sealing means 3 comprise a membrane that separates the gas contained in the cylinder from the external air at ambient pressure AP.

[0045] The adoption of the membrane 3 advantageously eliminates the presence of gaskets along the head 5 of the rod 2 and allows the rod 2 to be moved at high speeds, without generating overheating due to friction. In detail, Figures 1 and 2 show a spring 10 equipped with a membrane 3 fixed within the cylinder 1 along its internal wall 6, so as to keep the gas within it. The membrane 3 is fixed at an intermediate height of the wall 6, so as to allow the head 5 of the rod 2 to be housed within the cylinder 1 , and to be able to compress the gas on the opposite side of the membrane 3 relative to the head 5.

[0046] More specifically, the perimeter of the membrane 3 is fixed along the internal wall 6 of the cylinder 1 along an anchoring line 7. For example, the cylinder 1 can be made of two pieces, one comprising the bottom 8 of the cylinder 1 and adapted to receive and contain the gas 4, and the other comprising the part of the cylinder adapted to receive the head 5 of the rod 2: the anchoring line 7 can be configured at the junction of these two pieces, for example by threading.

[0047] In a variant of the invention, shown in Figure 3, the anchoring line may be absent, and the gas can be entirely contained and enclosed within a hollow membrane, housed within the cylinder 1 . In this case, it is possible to position end stops 9 at an intermediate height of the internal wall 6 of the cylinder 1 , so as to limit the stroke of the head 5 of the rod 2.

[0048] In a further variant of the invention, shown in Figure 4, the oil 11 , or in any case a fluid different from the gas 4, can be provided between the head 5 of the rod 2 and the membrane 3, so as to distribute the pressure of the rod 2 on the membrane 3 more uniformly.

[0049] According to preferred variants of the invention, the membrane is flexible but not extensible, ensuring that its surface area remains constant, while the head 5 of the rod 2 compresses the volume of the gas contained within it.

[0050] In other words, according to this variant of the invention, the laminar element that constitutes the membrane is non-elastic, meaning that after deformation, for example due to the expansion of the gas 4 or the compression caused by the rod 2, it does not change its volume.

[0051] In this way, excessive stresses are not generated in the membrane, and there is no risk of creating damage on its surface.

[0052] Operationally, the gas 4 is loaded into the spring 10 while the membrane is positioned inside the cylinder 1 during the assembly of the spring 10 itself. Once the spring 10 is positioned in its operating station, the rod 2 begins to move along its axis, with its head 5 moving along the internal wall 6 of the cylinder 1 , compressing and releasing the gas 4 contained by the membrane 3 at the bottom 8 of the cylinder 1.

[0053] In further variants of the invention, shown in Figures 5-7, the rod 22 of the spring 20 has a chamber 13 within which a second hollow rod 12, integral with the cylinder 21 , slides. In this case, the membrane 3 is anchored to the bottom of the cylinder 21 and around the second rod 12.

[0054] In this case, the first fluid 4 can be provided within the cylinder 21 , and a second fluid 11 , different from the first fluid 4, can be provided within the chamber 13 of the rod 22, so as to distribute the pressure of the rod 22 on the membrane 3 more uniformly.

[0055] In detail, the second fluid 11 can be at atmospheric pressure to avoid counteracting the motion of the cylinder 21 (Figure 5), or at a known and calibrated pressure so as to better distribute the tensions on the membrane and reduce the friction between the moving elements, for example by anchoring a second membrane 14 within the chamber 13 of the rod 22 so as to isolate the second fluid 11 from the outside (Figure 6), or to increase the thrust force of the spring 10.

[0056] Furthermore, with reference to Figure 7, it is possible to provide a third fluid 15 with appropriate viscosity, forced to pass through the ducts 16 appropriately calibrated and obtained between the second rod 12 and the internal walls of the chamber 13 of the rod 22; alternatively, such ducts 16 can be obtained directly on the second rod 12 or along the opening of the chamber 13.

[0057] In detail, a second fluid 11 can be provided in the chamber 13, to increase the thrust force of the spring 20, and the aforementioned third fluid 15 can be provided, passing through the ducts 16.

[0058] In this case, the gaskets 17 can be present when the third fluid is an oil, for example an incompressible oil, which acts as a braking agent passing through the ducts 16, since it slows down the movement and keeps the gaskets 17 themselves lubricated. The invention as conceived and illustrated herein is susceptible to numerous modifications and variations, all of which fall within the scope of the inventive concept.

[0059] Furthermore, all the details may be replaced with other technically equivalent elements.

[0060] Finally, the components used, provided they are compatible with the specific use, as well as the dimensions, may vary according to the needs and the state of the art. Where the features and techniques mentioned in any claim are followed by reference signs, such reference signs have been included with 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 such reference signs.

Claims

AMENDED CLAIMS received by the International Bureau on 27 May 2025 (27.05.2025)1. A gas spring (10, 20) for dies or molds comprising a fixed body (1 , 22); a movable body (2, 21 ); sealing means (3) for containing a first fluid (4) within the spring (10, 20), so as to transition from a first extended configuration wherein the first fluid (4) is expanded to a second contracted configuration wherein the first fluid (4) is compressed between the movable body (2, 21 ) and the fixed component (1 , 22), wherein the sealing means comprise a first membrane (3) adapted to contain the first fluid (4), the first membrane (3) is fixed within the fixed body (1 , 22) or the movable body (21 ) along a fastening line (7), the fixed body (1 ) and / or the movable body (2) comprises a first component (8) and a second component, the gas spring (10) being characterized in that the first component (8) is adapted to contain the first fluid (4) the second component is adapted to partially receive and to couple with the movable body (2) or the fixed body (1 ), the first component (8) and the second component have the same crosssection, and in that the fastening line (7) is formed at the junction of the first component (8) with the second component, wherein it provides a second fluid (11 ), external to the first membrane (3), adapted to distribute the compressive force exerted by the movable body (2, 21 ) on the first fluid (4) and a second membrane (14) adapted to contain the second fluid (11 ).2 The gas spring (10, 20) according to claim 1 , characterized in that it provides a third fluid (15) between the first membrane (3) and the second membrane (14).

3. The gas spring (10, 20) according to claim 2, characterized in that the third fluid is an oil, and in that calibrated ducts (16) are provided between the fixed body (1 , 22) and the movable body (2, 21 ), the oil flowing through said calibrated ducts (16) so as to determine the reciprocal movement speed between the fixed body (1 , 22) and the movable body (2, 21 ).

4. The gas spring (10, 20) according to one of claims 1 -3, characterized in that the first membrane (3) and / or the second membrane (14) is hollow and entirely contains the first fluid (4) and / or the second fluid (11 ), respectively.5 5. The gas spring (10) according to one of claims 1 -4, characterized in that it provides end stops (9) to limit the travel of the movable body (2, 21 ).

6. The gas spring (10, 20) according to one of claims 1 -5, characterized in that the first membrane (3) and / or the second membrane (14) is of the non-elastic type.10

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