Patent Description:
In particular, the invention concerns a shock absorber device of the gas spring type, provided with a double braking effect, regardless of the installation and work orientation of the shock absorber device.

Embodiments of the present invention can be applied, by way of non-restrictive example only, to the mechanisms for opening and closing components such as furnishing elements, frames, doors or windows, gates, trunks, or hatches for means of transport, industrial machines, medical or fitness apparatuses, or suchlike.

It is known that most of the opening/closing mechanisms of components such as furnishing elements, frames, doors or windows, gates, trunks for means of transport, industrial machines, medical or fitness apparatuses, or suchlike, are equipped with shock absorber devices.

These shock absorber devices are configured to facilitate the opening travel, or more generally the reciprocal distancing of two components connected to each other by an opening/closing mechanism reducing the necessary force that a user must impart, and to control the reciprocal closing travel, in order to prevent them colliding with each other, which, especially in the case of very heavy components, could cause damage to them.

For example, shock absorber devices are known, also indicated as gas springs, comprising a cylinder, inside which there is a gas, and a piston sliding in the cylinder, in which the compression force of the gas determines a pneumatic-type braking action.

The braking action given by the gas, however, for certain applications may not be sufficient, for example in the case of very heavy, or very delicate components, or if a more effective braking and slowing down action is required.

To try to solve these problems, shock absorber devices of the gas spring type have been developed, which provide a double braking action, both hydraulic and pneumatic. <FIG> show a known shock absorber device <NUM> of the gas spring type, which comprises a containing body <NUM> and a chamber <NUM> inside which at least a first operating fluid F1 is confined in its gaseous state and under pressure, for example nitrogen. The shock absorber device <NUM>, also, comprises a piston <NUM> able to slide axially inside the chamber <NUM> and integral with a stem <NUM>, which acts as an actuation member and partly protrudes from the containing body <NUM> from an aperture <NUM> of the latter in correspondence with one of its ends 111a. The stem <NUM> is provided with an external end 113a, always disposed outside the chamber <NUM>, and with an opposite internal end 113b, always disposed inside the chamber <NUM>, to which the piston <NUM> is connected. The piston <NUM> divides the space inside the containing body <NUM> into a first zone between the piston <NUM> and the end 111a, and a second zone, disposed on the opposite side of the piston <NUM> with respect to the first zone.

The first operating fluid F1 is compressed due to the advance of the stem <NUM> and therefore of the piston <NUM> inside the chamber <NUM>, returning an opposite thrust, and, thus, behaving like a traditional mechanical spring, which is compressed during a travel of the stem <NUM> toward the inside of the chamber <NUM>, and expands during the opposite travel.

The entry and exit speed of the stem <NUM> can be adjusted through suitable holes <NUM>, or through channels provided on the piston <NUM>.

The known shock absorber device <NUM>, also, comprises a second operating fluid F2, having a density greater than the first operating fluid F1, such as for example a mineral oil, which is inserted inside the chamber <NUM> to further slow down the speed of the stem <NUM> and of the piston <NUM>. In this way, when the piston <NUM> passes through the second, denser operating fluid F2, it is subjected to a greater slowdown than that provided by the first fluid.

In the traditional shock absorber device <NUM> shown in <FIG> there are, therefore, two types of travel: a pneumatic one in which the piston slides through the aeriform fluid, and a hydraulic one in which the piston slides through a fluid in its liquid state.

This known solution, however, has application limits, dictated by the orientation of installation, and of work, of the shock absorber device, which, for this reason, is not effective in all conditions of use.

One of the disadvantages of these known shock absorber devices, in fact, is that the second fluid in its liquid state is free to move inside the chamber, so that in order to confine the fluid in its liquid state in a working position, suitable for braking, the shock absorber device must be used in a vertical position, or at least in a position that is only slightly inclined, so as to allow the liquid fluid to collect in one or the other end of the chamber.

This disadvantage is particularly evident and felt when the shock absorber device is placed in a horizontal position, as for example shown in <FIG>, in which the second fluid F2 in its liquid state is homogeneously distributed on the bottom, or along the lateral wall of the chamber <NUM>. In this condition, in fact, the hydraulic braking effect is practically zero.

Documents <CIT>, <CIT>, <CIT> and <CIT> disclose shock absorber devices of a known type.

There is therefore a need to perfect a double-effect shock absorber device, that is one which has a double shock absorber and braking action, which can overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to provide a double-effect shock absorber device able to guarantee a high degree of braking in any of its installation/work orientations, even if the shock absorber device is in a horizontal position.

Another purpose of the present invention is to provide a shock absorber device which allows to obtain higher levels of shock absorption and braking effects than known shock absorber devices.

Another purpose of the invention is to provide a shock absorber device that is simple and inexpensive to manufacture but is efficient and effective on every occasion and in different applications.

Another purpose of the present invention is to provide a shock absorber device which has sizes comparable to those of known shock absorber devices and can be used to easily replace them in already existing applications.

Another purpose of the present invention is to obtain a device which allows to effectively slow down the travel of a mobile element toward/away from a fixed element in any working condition.

The Applicant has studied, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

The dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purposes, a shock absorber device according to the invention, which overcomes the limits of the state of the art and eliminates the defects present therein, comprises a containing body defining at least one chamber inside which at least a first operating fluid is confined.

The shock absorber device, also, comprises a first plunger able to slide axially inside the chamber to compress/expand the first operating fluid.

The first plunger comprises a first piston, sliding in the chamber, and a first actuation member connected to the piston, which partly protrudes from one end of the containing body.

The sliding piston divides the chamber into a first zone disposed between the piston and the end of the containing body, and a second zone disposed on the opposite side of the piston with respect to the first zone.

The piston is provided with channels, or passage gaps, through which the first operating fluid can pass.

The first operating fluid determines a braking pressure which acts on the first piston, causing a first braking action thereof.

The first plunger is provided with an external end, in correspondence with the end of the actuation member, which is always outside the chamber, and with an opposite internal end, in correspondence with the first piston, which is always inside the chamber.

In accordance with one aspect of the present invention, the shock absorber device comprises an internal shock absorber unit disposed inside the chamber.

The internal shock absorber unit comprises a diaphragm configured to divide the chamber into a first braking section, inside which the first operating fluid is confined, and into a second braking section.

A second operating fluid is confined inside the second braking section.

Thanks to the presence of the diaphragm, the chamber is hermetically divided into two completely separate braking sections, and between which there is no exchange of fluids. This allows to keep the second operating fluid confined in correspondence with one end of the containing body, preventing the dispersion thereof, which, otherwise, in some installation conditions, could result in a reduced, if not zero, shock absorption action.

According to some embodiments, the second operating fluid can be configured to have a greater resistance than the first operating fluid, so as to cause a slowing down of the speed of movement of the first plunger with respect to that supplied by the first operating fluid.

The internal shock absorber unit, also, comprises a second plunger able to slide axially in the second section and slidingly associated with the diaphragm.

The second plunger comprises a second piston able to slide axially in the second section, and a second actuation member connected to the second piston, which partly extends in the first section through the diaphragm.

The second plunger is provided with a distal end in correspondence with the actuation member, which is always disposed inside the first braking section and is suitable to cooperate, during use, with the first plunger, and with an opposite proximal end, in correspondence with the second piston, which is always disposed inside the second braking section and slides inside the second operating fluid.

The first and second plungers are configured to cooperate with each other, so that the braking action supplied by the second operating fluid acting on the second plunger, is transferred to the first plunger, slowing down its speed of movement.

In particular, during use, and in the closed condition of the shock absorber device, the internal end of the first plunger, that is the first piston, comes into contact with the distal end of the second plunger, that is the second actuation member.

This configuration of the shock absorber device allows to obtain a first shock absorption, given by the first plunger cooperating with the first operating fluid, and a second shock absorption, given by the cooperation of the first plunger with the second plunger, and with the second operating fluid.

According to some embodiments, the first operating fluid can be an aeriform or gaseous fluid, while the second operating fluid can be a fluid in its liquid state. In this case, a first pneumatic shock absorption, and a second hydraulic shock absorption are obtained.

According to a possible variant, the first operating fluid is a gaseous fluid having a first pressure, and the second operating fluid can be a gaseous fluid having a second pressure, greater than the first pressure. According to this variant, both braking actions can be the pneumatic type.

According to the present invention, the diaphragm can be configured to deform or move in such a way as to compensate for the increase in volume of the second section given by the entry into it of a portion of the second stem.

According to some embodiments, the diaphragm and the second plunger are floating on said second fluid and are configured to move in the opposite direction to the movement of the second stem.

According to further embodiments, the internal shock absorber unit comprises elastic means disposed inside the second section and configured to exert sufficient force on the second plunger to return it to the extended condition, that is the condition in which the portion of the second stem, outside the second section of the chamber, is maximum. This guarantees that the second plunger, when not stressed by the first plunger, always returns to the extended condition. Since the gas pressure inside the first section acts in the same way both on the diaphragm, and also on the second plunger, in fact, both are stationary because the forces are balanced.

According to further embodiments, the internal shock absorber unit comprises a containing element configured to contain the elastic element and keep it at least partly compressed, preventing its complete extension when there is no force acting on it.

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example, with reference to the attached drawings wherein:.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the figures.

We will now refer in detail to the various embodiments of the present invention, of which one or more examples are shown in the attached figures. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, the characteristics shown or described, insomuch as they are part of one embodiment, can be varied or adopted on, or in association with, other embodiments to produce another embodiment. It is understood that the present invention shall comprise all such modifications and variants.

Before describing these embodiments, we must, also, clarify that the present description is not limited in its application to details of the construction and disposition of the components as described in the following description using the attached figures. We must, also, clarify that the phraseology and terminology used here is for the purposes of description only and cannot be considered as limitative.

Embodiments described here concern a shock absorber device, indicated by the reference number <NUM> in the attached figures. In particular, the shock absorber device <NUM> is a gas spring, provided with a double shock absorber and braking effect.

By way of example only, the device <NUM> can be applied in the doors or trunks of motor vehicles, in the protective casings of industrial machines, in doors for furniture, in medical and fitness apparatuses, on motorized curtains and covers, inside the sale counters of supermarkets and butchers or travelling sales counters, or other.

In accordance with some embodiments, shown for example in <FIG>, the shock absorber device <NUM> comprises a containing body <NUM>, which defines a chamber <NUM> inside which at least a first operating fluid F1 is confined.

According to some embodiments, the first operating fluid F1 can be a gaseous fluid. By way of example, the first operating fluid F1 can be, for example, air, nitrogen, or other gas.

According to possible embodiments, the containing body <NUM> can have a circular cross section, which allows to obtain a homogeneous distribution of the pressure of the fluid inside the chamber <NUM>, and therefore to avoid points, or zones, where tensions are concentrated, which could cause malfunctions or failures of the material that constitutes the containing body <NUM>. Advantageously, the section is constant along an operating axis X along which the containing body <NUM> develops.

According to other embodiments, however, the containing body <NUM> can have a polygonal or elliptical section shape.

The containing body <NUM> has an open end 11a in correspondence with which there is an aperture <NUM>, and an opposite bottom end 11b.

The bottom end 11b can be provided, externally, with an attachment joint, not shown, provided to allow the installation of the shock absorber device <NUM>.

The device <NUM>, also, comprises a first plunger <NUM> able to slide axially inside the chamber <NUM> to compress/expand the first operating fluid F1.

The first plunger <NUM> can be inserted at least partly inside the chamber <NUM> in correspondence with the aperture <NUM> defined axially on the containing body <NUM>.

Sealing and guide means <NUM> can be disposed inside the chamber <NUM> in proximity to the aperture <NUM> both to seal the chamber <NUM> hermetically with respect to the outside, preventing leakages of the first operating fluid F1, and also to guide the plunger <NUM> at least in the initial segment, allowing to prevent unwanted peak loads.

According to possible embodiments, the sealing and guide means <NUM> can be chosen in a group comprising sealing rings, support ring nuts, gaskets, or a combination thereof.

The first plunger <NUM> is provided with an external end 13a, always disposed outside the chamber <NUM>, in any operating condition whatsoever, and with an opposite internal end 13b, always disposed inside the chamber <NUM>.

In accordance with some embodiments, the first plunger <NUM> comprises an actuation member, for example a stem <NUM>, able to slide axially inside the chamber <NUM>. The stem <NUM> extends along the operating axis X, at least partly protruding from the containing body <NUM> through the aperture <NUM>.

The first plunger <NUM>, also, comprises a piston <NUM> attached to the stem <NUM> in correspondence with its internal end 13b.

The piston <NUM> is configured to slide inside the first operating fluid F1, receiving a braking pressure from it.

In accordance with some embodiments, the piston <NUM> can be provided with passage gaps <NUM>, or through holes, configured to allow the passage of the first operating fluid F1 from one part of the piston <NUM> to the other in an axial direction. The shape and size of the passage gaps <NUM> allow to adjust the sliding speed of the stem <NUM> inside the chamber <NUM>.

In correspondence with an external end 13a, the stem <NUM> can have an attachment joint, not shown, opposite to an attachment joint disposed on the containing body <NUM>.

The stem <NUM> can have a substantially cylindrical section, but in general it can have any section shape whatsoever, even not correlated to the section shape of the chamber <NUM>, since the function of the stem <NUM> is to decrease the free volume of the chamber <NUM>, and increase/decrease the pressure of the first operating fluid F1 present therein so as to be subjected to a braking pressure, in this case of the pneumatic type.

The stem <NUM> can have a transverse size, in this case the external diameter, smaller than the transverse size, in this case the internal diameter, of the chamber <NUM>. In particular, the ratio between the internal diameter of the chamber <NUM> and the external diameter of the stem <NUM> can be correlated to a pneumatic braking factor of the plunger <NUM> with respect to the first operating fluid F1. In fact, with the same mass and initial pressure of the first operating fluid F1 present in the chamber <NUM>, the greater the external diameter of the stem <NUM>, the greater the pneumatic braking factor.

The piston <NUM> can have a shape substantially correlated to the cross section of the chamber <NUM>. In particular, the piston <NUM> can have a transverse size slightly less than the transverse size of the chamber <NUM>, so as to allow the sliding contact of the piston <NUM> on the lateral walls of the chamber <NUM> preventing, at the same time, any peripheral leakages of the first operating fluid F1.

In accordance with some embodiments, to facilitate the sliding of the piston <NUM> along the lateral walls of the chamber <NUM>, the piston <NUM> can be equipped with sliding means <NUM>, for example balls.

In accordance with one aspect of the present invention, the device <NUM> comprises an internal shock absorber unit <NUM> disposed inside the chamber <NUM>, which is configured to confer a second braking action on the first plunger <NUM> in addition to the braking action supplied by the first operating fluid F1.

According to some embodiments, the internal shock absorber unit <NUM> comprises a diaphragm <NUM> configured to hermetically divide the chamber <NUM> into a first braking section 12A and a second braking section 12B.

The first operating fluid F1 is confined inside the first braking section 12A.

In the second braking section 12B a second operating fluid F2 is confined.

In accordance with some embodiments, the second operating fluid F2 has a different density than the first operating fluid F1.

According to some embodiments, the second operating fluid F2 can have density and/or pressure greater than the first operating fluid F1, exerting a braking and slowing action which is greater than that supplied by the first operating fluid F1.

According to some embodiments, the second operating fluid F2 can be a fluid in its liquid state. In this case, a first pneumatic shock absorption and a second hydraulic shock absorption are obtained.

According to a possible variant, the second operating fluid F2 can be a gaseous fluid having a second pressure, greater than the first pressure. According to this variant, both the braking actions can be the pneumatic type.

The first operating fluid F1 can be a fluid in the gaseous state under pressure, selected in a group comprising air, nitrogen, or other gases, or a combination thereof.

The second operating fluid F2 can be a fluid in its liquid state selected from a group comprising mineral oil, vegetable oil, or silicone oil, or a combination thereof.

According to some embodiments, the internal shock absorber unit <NUM>, also, comprises a second plunger <NUM> slidingly associated with the mobile diaphragm <NUM>.

The second plunger <NUM> is configured to cooperate with the second operating fluid F2.

The second plunger <NUM> is provided with a distal end 20a, which is always disposed inside the first braking section 12A and is configured to cooperate with the first plunger <NUM>, and with an opposite proximal end 20b, which is always disposed inside the second braking zone 12B and cooperating with the second operating fluid F2 to exert a braking action on the first plunger <NUM>.

Thanks to the presence of the diaphragm <NUM>, it is possible to confine the second operating fluid F2 in a desired way, preventing, for example, spillages thereof throughout the chamber <NUM>. Being able to confine the second operating fluid F2 to one end of the chamber <NUM> allows to make the hydraulic braking effect always effective, regardless of the position of installation and of work of the shock absorber device <NUM>.

In accordance with some embodiments, the second plunger <NUM> comprises a second actuation member, for example a stem <NUM> which extends along the operating axis X and is completely and always contained inside the chamber <NUM>.

According to some embodiments, the second stem <NUM> has a smaller transverse size than the transverse size of the first stem <NUM>.

The second stem <NUM> is able to be thrust in the direction of the operating axis X, in correspondence with its distal end 20a, by the first plunger <NUM>, in particular by the piston <NUM> or by the internal end 13a of the stem <NUM>. For this purpose, the distal end 20a can have a substantially flat surface profile so as to increase the area of contact with the piston <NUM> or the internal end 13b and guarantee an effective, uniform and perfectly axial thrust effect.

The second plunger <NUM>, similarly to the first plunger <NUM>, comprises a second piston <NUM> attached to the stem <NUM> in correspondence with the proximal end 20b. The piston <NUM> is positioned between the mobile diaphragm <NUM> and the bottom end <NUM>1b of the containing body <NUM>.

The piston <NUM> can have a shape substantially correlated to the cross section of the chamber <NUM>. In particular, the piston <NUM> has a transverse size slightly less than the transverse size of the chamber <NUM>, so as to allow the sliding contact of the second piston <NUM> on the lateral walls of the chamber <NUM> preventing, at the same time, peripheral leakages of the second operating fluid F2.

In accordance with some embodiments, to facilitate the sliding of the second piston <NUM> along the lateral walls of the chamber <NUM>, the second piston <NUM> can be equipped with sliding means <NUM>, for example balls.

In accordance with some embodiments, the second piston <NUM> can be provided with passage gaps <NUM> configured to allow the passage of the second operating fluid F2 from one part of the second piston <NUM> to the other in an axial direction. The shape and size of the passage gaps <NUM> allow to adjust the sliding speed of the second stem <NUM> inside the chamber <NUM>, in particular in the second braking section 12B.

The diaphragm <NUM> has a central passage <NUM> configured to allow the sliding of the second stem <NUM> and simultaneously prevent spillages of the first operating fluid F1 and the second operating fluid F2 at the center. The central passage <NUM> allows the second stem <NUM> to be disposed for one part inside the first braking section 12A and for the other part inside the second braking section 12B.

In accordance with some embodiments, the diaphragm <NUM> is configured to deform or move in the opposite direction to the direction of advance of the second stem <NUM> so as to compensate for the increase in volume of the second section 12B given by the volume of the portion of the second stem <NUM>.

This is very useful if the second operating fluid F2 is in its liquid state, and therefore not compressible, unlike the first operating fluid F1.

According to some embodiments, the diaphragm <NUM> can be floating, that is it can be free to slide inside the chamber <NUM> in the direction of the operating axis X. The movement of the diaphragm <NUM> is correlated to the thrust forces exerted by the first operating fluid F1 on one side, and by the second operating fluid F2 on the other side.

According to some embodiments, the diaphragm <NUM> can have a shape substantially correlated to the cross section of the chamber <NUM>. In particular, the diaphragm <NUM> can have a transverse size slightly less than the transverse size of the chamber <NUM>, so as to slide on the lateral walls thereof preventing, at the same time, peripheral leakages of the first operating fluid F1 in the second braking section 12B and of the second operating fluid F2 in the first braking section 12A.

In this specific case, the diaphragm <NUM> can have a discoidal cylindrical shape and include sliding means <NUM> both in correspondence with its external surface in sliding contact with the lateral walls of the chamber <NUM>, and also in correspondence with an internal surface of the central passage <NUM>, to allow effective movement of the stem <NUM>.

According to possible variant embodiments, the diaphragm <NUM> can be made of elastic and deformable material, and be attached in correspondence with the lateral walls of the chamber <NUM>.

In accordance with some embodiments, the internal shock absorber unit <NUM> can comprise elastic means configured to cooperate with the second plunger <NUM> and suitable to allow the second plunger <NUM> to return to the extended condition (see <FIG>) when the first plunger <NUM> is not in contact with it.

According to some embodiments, the elastic means comprise at least one elastic element <NUM> disposed resting on the bottom end 11b of the containing body <NUM> and configured to elastically support, and generate a counter thrust on, the second plunger <NUM>.

In accordance with possible embodiments, the elastic element <NUM> can be, for example, a mechanical spring chosen from a group comprising a helical spring, a disc spring or a rubber spring.

According to some embodiments, the elastic element <NUM> is disposed in the second braking zone 12B, completely, or almost, immersed in the second operating fluid F2. The elastic element <NUM> in particular can be disposed between the diaphragm <NUM> and the bottom end 11b.

In accordance with some embodiments, the internal shock absorber unit <NUM> comprises a containing element <NUM>, configured to contain the elastic element <NUM> and keep it at least partly compressed.

According to some embodiments, the containing element <NUM> can be shaped like an inverted cup or glass, configured to allow the support of the elastic element <NUM> on one side, and the support of the second plunger <NUM>, in particular of the second piston <NUM>, or of the second stem <NUM> on the other side.

According to some embodiments, the containing element <NUM> surrounds the elastic element <NUM> laterally, at least for a portion of its axial development, so as to allow the correct compression and extension thereof, preventing deformations of the elastic element <NUM>.

In addition, the containing element <NUM> allows to keep the elastic element <NUM> always compressed, preventing its complete extension at zero force.

According to some embodiments, the containing element <NUM> can be floating, that is mobile vertically along the operating axis X.

In this way, the containing element <NUM> can accompany the compression and extension of the elastic element <NUM>, allowing it to be kept compressed at all times.

According to some embodiments, the containing element <NUM> comprises a support wall <NUM> provided with a thrust surface 31a, on which the piston <NUM> or the stem <NUM> rests, and with a counter-thrust surface 31b, on which the elastic element <NUM> acts.

The support wall <NUM> is provided with through holes <NUM> configured to allow the passage of the second operating fluid F2 when the stem <NUM> enters the second braking zone 12B.

The containing element <NUM> comprises a lateral wall <NUM>, in this specific case, annular, configured to contain at least part of the elastic element <NUM> laterally. In particular, the height of the lateral wall <NUM> in the direction of the operating axis X is such that when the elastic element is completely compressed, the lateral wall <NUM> does not contact the bottom end <NUM>1b of the containing body <NUM>.

In accordance with some embodiments, shown in <FIG>, a possible operating sequence of the double-effect shock absorber device <NUM> is shown.

The first plunger <NUM> is configured to pass from a completely extended position in which the first stem <NUM> is almost completely outside the chamber <NUM>, that is outside the first braking section 12A (<FIG>), to a completely compressed position, in which the first stem <NUM> is almost completely inside the chamber <NUM>, that is inside the first braking section 12A and thrusts the second plunger <NUM> in the direction of the operating axis X (<FIG>).

When the first stem <NUM> enters the chamber <NUM>, the useful volume of the chamber <NUM> decreases, in this specific case that of the first braking zone 12A, and, consequently, the pressure of the first operating fluid F1, which acts on the first stem <NUM>, increases, defining a pneumatic slowdown thereon.

Similarly, the second plunger <NUM> is configured to pass from a standby position, extended, in which the second stem <NUM> is almost completely outside the second braking zone 12B (<FIG>), to an operating position, in which the second stem <NUM> is almost completely inside the second braking zone 12B and, thrust by the first plunger <NUM>, exerts a pressure on the second operating fluid F2, receiving from it a thrust in the opposite direction.

The action of the first plunger <NUM> on the second plunger <NUM> also determines a compression of the elastic element <NUM> (<FIG>).

When the second stem <NUM> enters the second braking zone 12B, the useful volume of the second braking zone 12B decreases, and the second operating fluid F2 generates, in addition to a further hydraulic - or pneumatic - slowdown of the second stem <NUM>, also a thrust in the direction of the operating axis X, contrary to the direction of movement of the stem <NUM>, on the diaphragm <NUM>.

The diaphragm <NUM> and the second plunger <NUM> are in a condition of balanced forces, on the one side subject to the pressure of the first operating fluid F1, and on the other side to a contrary pressure of the second operating fluid F2.

When the first plunger <NUM> moves away from the second plunger <NUM>, the elastic element <NUM> tends to extend again, generating sufficient force to return the second plunger <NUM> to the standby position, and therefore the first plunger <NUM> to the fully extended position.

It is clear that modifications and/or additions of parts may be made to the double-effect shock absorber device <NUM> as described heretofore, without departing from the scope of the present invention as defined by the claims.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of double-effect shock absorber device <NUM>, having the characteristics as set forth in the claims and hence all coming within the scope of protection defined thereby.

Claim 1:
Shock absorber device comprising:
- a containing body (<NUM>) defining a chamber (<NUM>) inside which at least a first operating fluid (F1) is confined, and provided with a closed bottom end (11b) and an opposite end (11a), in which there is an aperture (<NUM>);
- a first plunger (<NUM>) able to slide axially inside said chamber (<NUM>) and configured to compress/expand said first operating fluid (F1) to obtain a first braking action, said first plunger (<NUM>) comprising a first piston (<NUM>) able to slide in the chamber (<NUM>), and a first actuation member (<NUM>) connected to the piston (<NUM>), which partly protrudes from said aperture (<NUM>) of said containing body (<NUM>), and
- an internal shock absorber unit (<NUM>) disposed inside said chamber (<NUM>) and configured to provide a second braking action, which comprises:
- a diaphragm (<NUM>) configured to hermetically divide said chamber (<NUM>) into a first braking section (12A) inside which said first operating fluid (F1) is confined and into a second braking section (12B) inside which a second operating fluid (F2) is confined,
- a second plunger (<NUM>) slidingly associated with said mobile diaphragm (<NUM>), comprising a distal end (20a), disposed in said first braking zone (12A) and configured to cooperate with said first plunger (<NUM>), and an opposite proximal end (20b), disposed in said second braking zone (20b) and configured to cooperate with said second operating fluid (F2) in order to exert a second braking action on said first plunger (<NUM>), characterized in that said diaphragm (<NUM>) is configured to deform or move along said operating axis (X) so as to compensate for an increase in the volume of said second section (12B) given by the entry into it of a portion of said second plunger (<NUM>).