Power cylinder, and device for forcible opening of a door using such a power cylinder

Abstract

The invention relates to a power cylinder (V) comprising a body (100), a rod (200) and at least one piston (300) fixed to the rod, the piston (300) and the associated rod (200) moving in the chamber at least in one direction under the action of a fluid passing through an inner conduit formed in the rod (200), notable in that the inner conduit (230), axially offset, is formed in the rod (200), and the rod (200) is formed, on its lateral outer surface, with a transverse notch (250) whose depth is defined so as to meet the axially offset conduit (230), in such a way that the axially offset conduit (230) opens laterally out of the rod (200). The invention also relates to a device for forcible opening of a door using such a power cylinder.

Description

Description Title of the invention: DOOR FORCED OPENING CYLINDER AND DEVICE USING SUCH A CYLINDER

[0001] SCOPE OF THE INVENTION

[0002] The invention relates to the field of cylinders whose fluid supply is achieved by exploiting at least one channel provided in the rod and in particular to the characteristics enabling this supply to be implemented under the best conditions.

[0003] DESCRIPTION OF THE STATE OF THE TECHNOLOGY

[0004] The cylinders can be powered via their rods.

[0005] For example, document DE3637823 describes a pneumatic cylinder with a rod connected to a piston that divides a chamber into a push side and a pull side. The cylinder rod has two hollow channels that connect to the push side and the pull side, respectively. Supplying oil mist to the outer end of the rod, where the hollow channels open, controls the rod's extension and retraction.

[0006] In the proposed configuration, communication between the hollow conduits and the chamber's push and pull sides is achieved via a radial bore. This solution is complex and requires knowing the hollow conduit's position. The same applies to communication between the hollow conduits and the external environment for the rod's outer end. Furthermore, the piston and rod are a single unit, making this solution difficult to adapt. It is also clear that these drawbacks are compounded when considering a tandem or multi-stage cylinder configuration.

[0007] US3554088 describes a fastener setting device equipped with an actuator adopting a tandem configuration with a complex design with a multi-section rod traversed by a single axial and central conduit with which radial bores communicate for the purpose of circulating a fluid from the chamber to the rod and vice versa.

[0008] The connection between the piston and the rod requires screwing the sections together. Furthermore, the design requires multiple pistons, their spacing ensuring free passage of fluid from the radial bores in the rod into the chamber.

[0009] BRIEF DESCRIPTION OF THE INVENTION

[0010] The applicants conducted research aimed at developing a cylinder with a power supply utilizing at least one channel in the rod, designed to be both more compact and more powerful than those offered in the prior art. The adaptability of such a design to a tandem or multi-stage cylinder configuration was investigated. Furthermore, ease of manufacturing was a key consideration.

[0011] This research has led to the design and manufacture of a new jack that provides solutions to the drawbacks of jacks of the previous art.

[0012] According to the invention, this cylinder comprises a body, a rod and at least one piston fixed to the rod, the piston having two lateral faces and dividing into two volumes a chamber provided in the body, the piston and the associated rod moving in the chamber at least in one direction under the action of a fluid passing through an internal conduit provided in the rod.

[0013] This cylinder is remarkable in that the internal conduit, called offset, is made in the rod with a conduit axis parallel to and at a distance from the axis of the rod, and the rod is made on its lateral outer surface with a transverse notch whose depth is defined so as to meet said offset conduit so that said offset conduit opens laterally out of the rod.

[0014] This feature is particularly advantageous because it facilitates access to the outside of the duct. It is no longer necessary to drill radially through the rod to reach the duct, nor to know the precise angular position of the off-center duct to ensure that the drill hole reaches it.

[0015] The internal conduit, called the offset conduit, is made in the stem close to its outer surface so that the notch is not too deep and does not weaken the stem.

[0016] According to another particularly advantageous feature of the invention, said transverse notch is made on a cylindrical portion of rod contiguous to the piston so that the notch adopts a profile of which a part is formed by the surface of the piston and the other part is formed by the surface of the rod.

[0017] Thus, the notch is made on a part already pre-formed to cooperate with the piston, which makes it easier to manufacture.

[0018] In another embodiment, the transverse notch is formed by an annular groove or a shoulder located at one end of the stem. This feature is only possible if the groove does not weaken the stem.

[0019] According to another particularly advantageous feature of the invention, the rod is provided with a second internal conduit coaxial to the axis of the rod. This second conduit makes it possible to consider a dual-effect configuration implemented by two internal conduits provided in the rod: an offset conduit and an axial conduit.

[0020] One configuration for which the invention is particularly advantageous concerns a tandem or multi-stage cylinder. This configuration allows the actuator's power to be multiplied by increasing the surface area with which the fluid is in contact. According to another particularly advantageous feature, the cylinder comprises a plurality of pistons, and the rod is divided into several rod sections screwed together.

[0021] Furthermore, the body is broken down into several cylindrical body sections, each defining a chamber in which a piston moves, the ends of the cylindrical body sections being closed by screwed flanges.

[0022] According to another particularly advantageous feature, at least one piston is provided with an internal piston channel arranged parallel to its axis and corresponding to the offset internal channel of the rod section on which it is mounted, so that the offset internal channel opens on the other side of the piston. This feature allows the fluid to be delivered to the other side of the piston at the notch described above and vice versa. that is, from the chamber located on one side of the piston towards the offset internal conduit.

[0023] It allows the chambers on the same side (push or pull) to communicate with each other, which simplifies the single-acting or double-acting supply of a multi-stage cylinder such as the one in the invention.

[0024] According to another particularly advantageous feature, at least one section of rod is provided at one end with a cylindrical portion of rod section onto which a piston is fitted, provided with an axial bore for this purpose, this cylindrical portion of rod section receiving a piston is provided with a transverse orifice communicating the second axial conduit with the outside of the rod in said bore of the piston and the piston being provided with a transverse passage corresponding to the transverse orifice and opening onto one of the lateral faces of the piston.

[0025] By pre-forming the piston once again, this solution allows the fluid exiting the axial conduit to be directed outwards.

[0026] According to a preferred embodiment, with respect to the direction of advance of the rod, the transverse passage of the piston opens onto the lateral face corresponding to the pushing side of the cylinder.

[0027] According to another particularly advantageous feature of the invention, the rod sections screw together so that the internal axial conduits with which they are provided when they are equipped communicate.

[0028] With a notch allowing the offset conduit to open near the front face of the piston, the pre-forming of the rod sections and pistons enables independent communication between all the push and pull sides of each chamber. This makes the implementation of a multi-stage, double-acting cylinder possible and particularly compact, as only one power supply is required for each stroke.

[0029] Thus, according to another particularly advantageous feature of the invention, one of the flanges arranged between two body sections is provided with a supply conduit for the draw side of one chamber and a supply conduit for the push side of the adjacent chamber.

[0030] In order to match the orifices in the piston with those in the rod, the cylinder advantageously includes a centering pin positioned parallel to the axis of the rod between a portion of the rod and the piston in order to angularly orient the position of the piston around the axis of the rod.

[0031] This angular orientation ensures that the orifices and passages in the piston correspond with the opening parts of the conduits in the rod.

[0032] In a preferred embodiment, the portion of the rod onto which the piston is fitted has an inner diameter to that of the rest of the rod or rod section, so as to form a shoulder against which the piston rests. The centering pin is located on the transverse surface of this shoulder, and the offset internal conduit opens into this shoulder.

[0033] The power and compactness of such a cylinder are particularly useful in applications involving forced door opening, where the cylinder must be powerful, compact, and consume little fluid. Furthermore, the multi-stage design allows for the use of multiple identical parts, reducing manufacturing costs.

[0034] Thus, another object of the invention relates to a device for forcing open doors, windows and other openings, having an opening part and a fixed frame, comprising:

[0035] - a frame that is extendable in length and has two ends, formed of at least two sliding sleeves, an inner sleeve and an outer sleeve, allowing the ends to be moved closer together or further apart, in order to adapt to the width of the fixed frame on which it is installed,

[0036] - at least one recessed wedge at each end of the frame intended to bear against the chassis, said wedges being capable of moving closer together or further apart due to sliding,

[0037] - a first cylinder performing the motorized movement of the sliding sleeves and thus from one corner relative to the other, and subjecting the chassis to a constraint at the supports between said corners and the chassis, said first cylinder having a body housed in one of the sleeves and a free end of rod cooperating intermittently with the other sleeve, the starting point of its stroke is defined by an initial manual sliding between the two sleeves. This device is remarkable in that the first cylinder incorporates all or part of the characteristics of the tandem or multi-stage cylinder described above.

[0038] The fundamental concepts of the invention having been set forth above in their most elementary form, other details and characteristics will become clearer upon reading the description that follows and in view of the attached drawings, which give, by way of non-limiting examples, embodiments of a cylinder according to the invention.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] [Fig. 1] is a schematic drawing of a side view in section of an embodiment of a double-acting cylinder according to the invention;

[0041] [Fig. 2] is a schematic drawing of a side view in section of an embodiment of a double-acting multi-stage cylinder according to the invention;

[0042] [Fig. 3] is a schematic drawing of a side view of the rod and piston assembly of the cylinder in Figure 2;

[0043] [Fig. 4] is a schematic drawing of a side view of a section of rod;

[0044] [Fig. 5] is a schematic drawing of a right-side view of the rod section in Figure 4;

[0045] [Fig. 6] is a schematic drawing of a left-side view of the rod section in Figure 4;

[0046] [Fig. 7] is a schematic drawing of a side view of a piston;

[0047] [Fig. 8] is a schematic drawing of a front face view of the piston in Figure 7;

[0048] [Fig. 9] is a schematic drawing of a rear face view of the piston in Figure 7;

[0049] [Fig. 10] is a schematic drawing of a cross-sectional side view of a preformed flange of supply conduits;

[0050] [Fig. 11] is a schematic drawing of a rear face view of the flange in Figure 10.

[0051] Fig. 12 is a schematic drawing of an embodiment of a device for forcing open doors, windows and other openings, having an opening part and a fixed frame.

[0052] DESCRIPTION OF PREFERRED METHODS OF IMPLEMENTATION

[0053] As illustrated by Figure 1, the cylinder referenced V as a whole is a double-acting cylinder comprising a body 100, a rod 200 and a piston 300.

[0054] To facilitate reading the drawings and understanding the invention, the front of the cylinder is considered the rod extension side and the rear the non-extension side. Pushing the rod extends it forward, and retraction is a translation in the opposite direction.

[0055] Piston 300 is screwed onto the inner end 210 of rod 200.

[0056] The body 100 is formed by a tube 110, the two ends of which are closed by flanges 410 and 420. Seals contribute to the sealing of the connection between the tube and the flanges. The front flange 420 has an axial bore through which the rod 200 passes. The hollow volume defined by the tube 110 and closed by the flanges constitutes the chamber 500 of the cylinder V1.

[0057] The piston 300 comprises two lateral faces and separates the chamber 500 into two volumes: A push volume or side 510 into which the fluid enters for the purpose of the rod 200 exiting and a pull volume or side 520 into which the fluid enters for the purpose of the rod 200 retracting. The piston 300 is equipped on its periphery with a seal to ensure the sealing between the volumes.

[0058] The functional module for fluid supply and / or distribution is not shown.

[0059] According to a preferred but not limiting embodiment, the fluid is compressed air.

[0060] According to the invention, the supply, i.e. the entry and exit of the fluid from the two volumes 510 and 520, is carried out by the rod 200.

[0061] To this end, the rod 200 is provided with two internal conduits 230 and 240. These conduits allow communication between the exterior of the cylinder V and the two volumes 510 and 520.

[0062] A first internal conduit 230 has an axis parallel to the axis of the rod 200 and is offset by being made in the rod 200 near its outer cylindrical surface.

[0063] The second internal conduit 240 is coaxial with the rod 200.

[0064] The first offset conduit 230 opens flush with the transverse flat surface of the outer end 220 of the rod 200 and communicates with the volume corresponding to the withdrawal side 520.

[0065] To do this, a transverse notch 250 is made on the outer surface of the rod 200 with a depth enabling it to meet said offset conduit 230 so that said offset conduit 230 opens out of the rod 230 into the recessed side 520 of the chamber 500.

[0066] The conduit 230 is therefore here a blind hole whose non-opening end communicates with the outside of the rod 200 by means of a sufficiently deep transverse notch 250.

[0067] As illustrated, said notch 250 is made on a cylindrical portion of rod 200 adjoining the cylindrical portion 211 onto which the piston 300 is screwed and therefore opens into the volume 520. This positioning allows the fluid to circulate even when the piston 300 is at the end of the rod's exit stroke.

[0068] The second internal conduit 240 is coaxial and opens flush with the transverse flat surface of the outer end 220 of the rod 200. It communicates with the volume corresponding to the thrust side 510. To do this, it opens flush with the transverse flat surface of the inner end 210 of the rod 200. As the piston 300 has a through-threaded axial bore for its attachment to the rod 200, the conduit 240 opens directly into the volume 510.

[0069] This V-cylinder allows the functionalities of a double-acting cylinder to be implemented while maintaining a compact body without protrusion due to the rod feed, while providing a simpler rod design by avoiding the creation of radial bores to allow the internal conduits to communicate with the two volumes of the chamber.

[0070] Figures 2 to 13 illustrate one embodiment for a so-called tandem or tiered configuration.

[0071] As illustrated by Figure 2, the cylinder referenced V' as a whole is a double-acting cylinder comprising a body 100', a rod 200' and a plurality of pistons 300a', 300b', 300c' and 300d'.

[0072] The body 100' is formed by a plurality of cylindrical body sections or tubes 110a', 11 Ob', 110c', 110d'. The two ends of each tube are closed by screwed flanges 410', 420', 430', 440', 450', which are shared between two tubes (for flanges 420', 430', and 440') when they are adjacent. Gaskets contribute to the sealing of the connection between the tube and the flanges.

[0073] The front flange 450' has an axial bore fitted with seals through which the rod 200' passes. The hollow volume defined by the various tubes 110 and closed by the flanges constitutes the four chambers 500a', 500b', 500c', 500d' of the cylinder V'. Each chamber houses a piston 300a', 300b', 300c' and 300d'.

[0074] In addition, the rod 200' is broken down into a plurality of rod sections screwed together 200a', 200b', 200c', 200d'.

[0075] The pistons are fixed by clamping between the sections of the 200' rod or by direct screwing onto the 200a' rod section for the rear piston 300a' as proposed for the V cylinder described above.

[0076] Cylinder V' is shown at the end of its retraction stroke.

[0077] The piston separates the chamber in which it moves into two volumes:

[0078] A push volume or side into which the fluid enters for the purpose of the 200' rod's exit and a pull or withdrawal volume or side into which the fluid enters for the purpose of the 200' rod's retraction. The pistons are equipped on their periphery with a seal to ensure the seal between the volumes.

[0079] The functional module for supplying and / or distributing fluid is not shown. Here too, according to a preferred but non-limiting embodiment, the fluid is compressed air.

[0080] According to the invention, the supply, i.e. the inflow and outflow of fluid from the two volumes into each chamber, is carried out from the single intermediate flange 420' and by conduits arranged in the rod sections 200a', 200b' and 200c'.

[0081] As illustrated in more detail in Figure 3, only rod sections 200a', 200b', and 200c' have internal conduits. Rod section 200d' does not have internal conduits because the fluids come from section 200c' located upstream, one end of whose conduits opens into chamber 500d'.

[0082] To this end, the 200' rod is provided with two internal conduits 230' and 240'. These conduits allow communication between the thrust volumes and between the retraction volumes.

[0083] These conduits cooperate with orifices or passages made in the pistons which allow the fluid to pass through the conduit to one side or the other of the piston and therefore into the thrust volume or into the retraction volume.

[0084] This relationship appears for pistons 300b', 300c' and 300d'.

[0085] This is explained in more detail with reference to figures 4 to 9, which illustrate the rod section 200a' and the piston 300b', which is inserted once mounted onto the front end of the latter. The piston 300a' is positioned on the rear end by axial screwing and has no passage or orifice.

[0086] As illustrated by figures 4 to 6, the rod section 200a' is provided with a first internal conduit 230a' which has an axis parallel to the axis of the rod section 200a' and is offset by being made in the section 200a' near its outer surface.

[0087] The second inner conduit 240a' is coaxial with the rod section 200a'.

[0088] The first conduit 230a' opens flush with the transverse flat surface formed by a shoulder at the front end 220a' of the rod section and communicates with the volume corresponding to the withdrawal side of the chamber 500a'.

[0089] To achieve this, a transverse notch 250a' is made on the outer surface of the rod section 200a' with a depth enabling it to meet said offset conduit 230a' so that said offset conduit 230a' - it - emerges from the rear end 210a' of the rod section 200a' despite the presence of the piston 300a' which fits into it.

[0090] According to the illustrated embodiment, the notch 250a' opens both on the cylindrical surface and on the flat surface of the shoulder formed on the rear end 210a' and on which the piston 300a' rests.

[0091] The conduit 230a' is therefore not a blind hole but a hole opening at both ends. The notch 250a' allows it to open earlier so that the presence of the piston 300a' does not impede the fluid flow.

[0092] Positioning the notch near the front side face of the piston allows fluid to flow even when the 300a' piston is at the end of its rod extension stroke.

[0093] The second internal conduit 240a' is coaxial and opens flush with the transverse flat surface of both ends 210a' and 220a'. It communicates with the volume corresponding to the thrust side. As the piston 300a' has a through-threaded axial bore for its attachment to the end 210a', the conduit 240a' opens clearly at the rear into the thrust volume.

[0094] The front end 220a' of the rod is pre-formed with a shoulder defined by a coaxial cylindrical projection of smaller diameter, the distal end of which is threaded. An orifice 221a' is made by radial drilling in the unthreaded portion so as to radially connect the conduit 240a' (which also opens axially) with the exterior of the rod section 200a' at the unthreaded portion of the cylindrical projection. The rear end of the rod section 200b' is screwed onto this threaded end 220a' and clamps the piston 300b' against the front end 200a' of the section 200a'.

[0095] The flat surface defined by the pre-formed shoulder in the end 220a' is further pre-formed with a blind hole 222a' accommodating a centering pin whose function is explained below.

[0096] Indeed, in order to allow the conduits of the rod section to communicate with the volumes of the adjacent chamber, the piston itself is pre-formed with orifices and passages that cooperate with the ends of these conduits.

[0097] In addition to its central bore allowing it to fit onto the cylindrical projection of the end 220a' of the rod section 200a', the piston 300b' is provided with an offset internal piston channel 310b' arranged parallel to its axis. This channel connects the offset internal channel 230a' of the rod section 200a' on which it is mounted to the exterior of the piston 300a', meaning it opens onto the opposite lateral face, in this case, the front face. Communication with the shrinkage volume of the chamber 500b' is thus ensured. To optimize this, particularly when the piston is at the end of its stroke and the front lateral face is resting on the corresponding flange, the internal channel 310b' does not open onto the surface of the lateral face but into a radial groove 311b'.

[0098] The piston 300b' is further provided by a passage 320b' which corresponds to the transverse orifice 221a' formed in the end 220a' of the rod section 200a' and opening onto one of the lateral faces of the piston, in this case the rear face. Communication with the thrust volume of the chamber 500b' is ensured. To optimize this, the orifice 221a' is formed near the shoulder, and this passage 320b' consists of a radial groove.

[0099] It is understood that the piston ports and the conduits of the rod section must be aligned to ensure that the different chambers communicate with each other in the same volume. The pistons 300b', 300c', and 300d' on their respective rod sections must therefore be oriented angularly around the axis of the rod section.

[0100] Thus, the rear face of the piston 300b' is pre-formed with a blind hole 330b' accommodating a centering pin 331b' (see figure 3).

[0101] The conduits of the rod sections and the orifices provided in the pistons are made in such a way that once the centering pin 331 b' is positioned in the blind holes 222a' and 330b', they communicate.

[0102] Seals ensure the watertightness of these connections.

[0103] The rod sections screw together so that the internal axial conduits with which they are provided when they are equipped, communicate and form the 240' conduit.

[0104] As illustrated in Figures 2, 10, and 11, one of the flanges located between two body sections, namely flange 420', is provided with a supply conduit 421' for the draw or retraction side or volume of a chamber, here chamber 500a', and a supply conduit 422' for the push side of the adjacent chamber, here chamber 500b'. Because the rod sections are fitted with internal open conduits, only one flange of this type is required. These hollow flange conduits are formed of two parts:

[0105] - a radial part equipped with a thread extending from the outside of the flange, and

[0106] - a part parallel to the axis of the cylinder opening into the chambers.

[0107] The screw connection between the body sections and this flange 420' allows the conduits 421' and 422' to open to the outside.

[0108] The other flasks are more conventional.

[0109] According to a preferred embodiment, all parts except for the joints are made of aluminium, preferably of grade 7075.

[0110] Figure 12 illustrates a device for forcibly opening doors, windows, and other openings, comprising an opening part and a fixed frame. This device, referenced as D, includes as a whole: - a frame 600 extendable in length (according to the double arrow F1) and having two ends and formed of at least two sliding sleeves 610, 620, an inner sleeve and an outer sleeve allowing the distance between said ends, in order to adapt to the width of the fixed frame (not illustrated) on which it is installed, - at least one recessed wedge 612, 622 at each end of the frame intended to bear against the chassis, said wedges being capable of moving closer together or further apart due to sliding, - a V-type cylinder housed in the sleeves and performing the motorized movement of the sliding sleeves and therefore from one corner to the other, and subjecting the chassis to a stress at the supports between said corners and the chassis, said cylinder not being visible because its body is housed in one of the sleeves and a free end of the cooperating rod punctually with the other sleeve, the starting point of its stroke being defined by a first manual sliding between the two sleeves, a second thrust cylinder 700 placed substantially perpendicular to the frame 600 and taking support from the latter to push against the opening part.

[0111] It is understood that the cylinders and device described and illustrated above have been presented for disclosure rather than limitation. Of course, various adaptations, modifications, and improvements may be made to the examples presented, without departing from the scope of the invention.

[0112] Thus, for example, although the use of compressed air is preferred, the use of another fluid such as a hydraulic fluid can be considered.

Claims

Demands

1. A cylinder (V) comprising a body (100), a rod (200), and at least one piston (300) attached to the rod, the piston having two lateral faces and dividing into two volumes a chamber formed in the body with a pull side and a push side, the piston (300) and the associated rod (200) moving in the chamber in at least one direction under the action of a fluid passing through an internal conduit formed in the rod (200), the internal conduit (230), referred to as offset, being formed in the rod (200) with a conduit axis parallel to and at a distance from the axis of the rod (200), and the rod (200) having on its outer lateral surface a transverse notch (250) the depth of which is defined so as to meet said offset conduit (230) such that said offset conduit (230) opens laterally out of the rod (200),CHARACTERIZED BY THE FACT THAT said transverse notch (250) is made on a cylindrical portion of rod contiguous to the piston (300) such that the notch (250) adopts a profile of which a part is formed by the surface of the piston (300) and the other part is formed by the surface of the rod (200).

2. Cylinder (V) according to claim 1, CHARACTERIZED BY THE FACT THAT the rod (200) is provided with a second internal conduit (240) coaxial to the axis of the rod (200).

3. Cylinder (V') according to any one of claims 1 to 2, CHARACTERIZED IN THAT it comprises a plurality of pistons (300a', 300b', 300c', 300d') and the rod is broken down into several rod sections (200a', 200b', 200c', 200d') screwed together.

4. Cylinder (V') according to claim 3, CHARACTERIZED IN THAT the body (100') is broken down into several cylindrical body sections (110a', 110b', 110c', 110d') each defining a chamber in which a piston (300a', 300b', 300c', 300d') moves, the ends of the cylindrical body sections being closed by screwed flanges.

5. Cylinder (V') according to claims 3 or 4, CHARACTERIZED IN THAT at least one piston (300b') is provided of an internal piston conduit (310b') arranged parallel to its axis and corresponding with the offset internal conduit (230a') of the rod section (200a') on which it is received so that the offset internal conduit (230a') opens on the other side of the piston (300b').

6. Cylinder (V') according to claim 2 and any one of claims 3 to 5, CHARACTERIZED IN THAT at least one section of rod (200a') is provided at one end with a cylindrical portion (220a') of rod section onto which a piston (300b') is fitted, the piston having an axial bore for this purpose, this cylindrical portion (220a') of rod section receiving a piston is provided with a transverse orifice (221a') communicating the second coaxial conduit (240a') with the outside of the rod in said bore of the piston (300b') and the piston (300b') being provided with a transverse passage (320b') corresponding to the transverse orifice (221a') and opening onto one of the lateral faces of the piston (300b').

7. Cylinder (V') according to claim 5 or 6, CHARACTERIZED IN THAT it comprises a centering pin (331 b') positioned parallel to the axis of the rod between a portion of the rod and the piston in order to angularly orient the position of the piston around the axis of the rod.

8. Cylinder (V') according to claim 6, CHARACTERIZED IN THAT the transverse passage (320b') of the piston (300b') opens onto the lateral face corresponding to the thrust side of the cylinder.

9. Cylinder (V') according to any one of claims 3 to 8, CHARACTERIZED BY THE FACT THAT the rod sections (200a', 200b', 200c', 200d') screw together so that the internal axial conduits with which they are provided when they are equipped, communicate.

10. Cylinder (V') according to any one of claims 3 to 9, CHARACTERIZED BY THE FACT THAT one of the flanges (420') arranged between two body sections is provided with a supply conduit (421') for the draw side of a chamber (500a') and a supply conduit (422') for the push side of the adjacent chamber (500b').

11. Device (D) for forcibly opening doors, windows and other openings, having an opening part and a fixed frame, comprising: - a frame (600) extendable in length and having two ends and formed of at least two sliding sleeves, an inner sleeve and an outer sleeve allowing the said ends to be moved further apart or closer together, in order to adapt to the width of the fixed frame on which it is installed, - at least one recessed wedge (612, 622) at each end of the frame intended to bear against the chassis, said wedges being capable of moving closer together or further apart due to sliding, - a first cylinder (V') performing the motorized movement of the sliding sleeves and thus from one corner relative to the other, and subjecting the chassis to a stress at the supports between said corners and the chassis, said first cylinder having a body housed in one of the sleeves and a free end of rod cooperating occasionally with the other sleeve, the starting point of its stroke being defined by a first manual sliding between the two sleeves, CHARACTERIZED BY THE FACT THAT the first cylinder (V') is as claimed in any one of claims 3 to 10.

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