Locking system

Abstract

The present invention relates to a continuously variable locking system for a cylinder-piston arrangement, comprising a cylinder (1) having a cap (1c) and a base (1d), a piston (2), a closure (4) continuously variable between an open and closed position, and a fluid arranged in the cylinder (1), the piston (2) being movably arranged in the cylinder (1) and having at least one annular piston seal (2a) circumferentially on its outer surface, on which a piston rod (2b) is arranged, the piston rod (2b) being at least partially axially extruded at the cap end of the cylinder (1). The object of the present invention is to develop a locking system characterized by a robust and simple structure, which can be maintained and adapted in a particularly easy way, and which is at the same time reliable and precise in operation. For this purpose, the invention proposes the following: a cylinder is designed with a double wall having an inner sleeve (1a) and an outer sleeve (1b), a piston (2) is arranged in the inner sleeve (1a), a tubular compensator (3) having circumferentially running seals (3a) on its inner and outer surfaces, respectively, is displaceably arranged in the annular space between the inner sleeve (1a) and the outer sleeve (1b), a closure is arranged at the base end (1d) of the cylinder (1), and the base end of the inner sleeve (1a) can be closed by a closure (4).

Description

[Technical Field]

[0001] The present invention relates to a continuously variable locking system for a cylinder-piston arrangement, comprising a cylinder having a cap and a base, a piston, a closure continuously variable between an open and closed position, and a fluid disposed within the cylinder, wherein the piston is movably disposed within the cylinder and has at least one annular piston seal circumferentially disposed on its outer surface, and a piston rod disposed on the piston, the piston rod being at least partially axially extruded at a cap end of the cylinder. [Background technology]

[0002] Such a locking system is known, for example, from U.S. Pat. No. 5,699,499. The locking system disclosed therein is intended for use in infinitely damping and securing a car door. The closure is formed of several parts and is arranged inside the piston. When the locking system is locked, two opposing flow openings are closed by two closures and duckbill valves, each of which is pressed against the flow opening by a spring. When an axial compressive or tensile force is applied to the piston rod, the spring force is overcome and one of the two closures opens. The pressure inside the piston rises accordingly until the duckbill valve opens, allowing fluid to flow through the piston body. This allows the piston rod to be displaced to the desired position. As soon as the force on the piston rod is no longer applied, the flow openings are automatically closed again by the restoring force of the spring.

[0003] Besides motor vehicle doors, application areas for such locking systems are, for example, machine maintenance covers in workshops, fire doors and furniture assembly aids.

[0004] Known locking systems are relatively complex and inflexible. The arrangement of the multi-part closure mechanism in the piston is not only time-consuming and expensive to maintain, but also requires a great deal of effort to fit. In particular, the arrangement of the elastomeric duckbill valve in the piston is very complicated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE 4239681 A1 Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is therefore to develop the known continuously variable locking system in a way that is characterized by a robust and simple construction, is maintained and adapted in a particularly easy way, and at the same time is reliable and precise in operation. [Means for solving the problem]

[0007] For this purpose, starting from a locking system of the type mentioned at the outset, the invention proposes that the cylinder is double-walled with an inner sleeve and an outer sleeve, the piston is arranged in the inner sleeve, a tubular compensator having circumferentially running seals on its inner and outer surfaces, respectively, is displaceably arranged in the annular space between the inner and outer sleeves, and an adjustable closure is arranged at the base end of the cylinder, the base end of the inner sleeve being closable by the closure.

[0008] The locking system according to the invention forms inner and outer fluid chambers, separable by a closure and containing a fluid. The outer fluid chamber is a tubular annular space between the inner and outer sleeves, bounded on the base side by a closure and on the cap side by a compensator. The inner fluid chamber corresponds to a cylindrical space within the inner sleeve, bounded on the base side by a closure and on the cap side by a piston.

[0009] The closure can open, separate and close the connection between these two fluid chambers. When the closure is in the open position, the piston rod can be displaced axially. Depending on the direction of displacement, fluid flows from one fluid chamber to the other, respectively. The narrower the opening is set, the higher the damping of the piston rod's mobility. When the closure is in the closed position, the piston rod is locked and cannot move.

[0010] Depending on the requirements, the adjustment of the closure can be carried out via a suitable control mechanism, for example in the form of a mechanical lever, a spring, a hydraulic control, or an electronic control. In a preferred embodiment, the control mechanism is arranged outside the cylinder. This makes it easy to adapt the control mechanism, and therefore an essential part of the operating mode of the locking system, to changed requirements at any time.

[0011] In another advantageous development of the invention, the inner and outer sleeves are connected to one another in a form-locking and / or force-locking manner. Such a detachable solution allows for particularly simple assembly and problem-free maintenance of the locking system.

[0012] Corresponding threads on the inner and outer sleeves are particularly suitable for creating the connection.

[0013] Furthermore, it is advantageous if the closure is configured as a body that is rotationally symmetrical with respect to the longitudinal axis of the cylinder, as this rotational symmetry makes it possible to achieve a particularly uniform flow of fluid between the two fluid chambers.

[0014] In a particularly preferred geometrical embodiment of the closure, it is provided that the closure has a radially rising annular projection on the outer periphery and a radially descending central conical projection, whereby the flow opening is characterized by particularly suitable hydrodynamics.

[0015] As fluid, preferably hydraulic oil is used.

[0016] The present invention will be described in more detail below with reference to the drawings. [Brief explanation of the drawings]

[0017] [Figure 1] Schematic cross-sectional view of a locking system according to the invention in a dynamic state in an exemplary embodiment. [Figure 2] 2 shows a schematic view of the adjustment and locking of the piston rod in the exemplary embodiment according to FIG. 1; [Figure 3] 2 shows a schematic view of the adjustment and locking of the piston rod in the exemplary embodiment according to FIG. 1; [Figure 4] 2 shows a schematic view of the adjustment and locking of the piston rod in the exemplary embodiment according to FIG. 1; [Figure 5] 2 shows a schematic three-dimensional view of the closure of the locking system of FIG. 1; DETAILED DESCRIPTION OF THE INVENTION

[0018] FIG. 1 shows a cylinder of a locking system according to the present invention, designated by the reference numeral 1. The cylinder 1 has a double-walled design and accordingly comprises an inner sleeve 1a, an outer sleeve 1b, a cover 1c, and a base 1d. A piston 2 with a piston rod 2a is arranged within the inner sleeve 1a. According to the present invention, the piston and piston rod may have the same diameter, unlike in this exemplary embodiment. The piston rod 2a protrudes from the cap end of the cylinder 1 and is axially displaceable from the cylinder 1. Furthermore, the piston 2 has a circumferential annular piston seal 2b on its outer periphery. A hollow cylindrical compensator 3 is arranged in the annular space between the outer sleeve 1b and the inner sleeve 1a. The compensator 3 has seals 3a on its inner and outer surfaces. Furthermore, an axially displaceable closure element 4 is arranged at the base end of the cylinder 1. The closure element 4 has a circumferential seal 4a on its outer side. Adjustment of the closure element 4 is achieved by a suitable control (not shown). The control may be formed, for example, as a mechanical lever or spring, but hydraulic or electronic control is also possible.

[0019] The inner sleeve 1a and the outer sleeve 1b have corresponding threads at the cap ends, so that the inner sleeve 1a can be screwed onto the outer sleeve 1b.

[0020] The locking system according to the invention therefore has two fluid chambers, namely an outer fluid chamber 5 and an inner cylindrical fluid chamber 6, the outer fluid chamber 5 being defined by the inner wall of the outer sleeve 1b and the outer wall of the inner sleeve 1a and by the closure 4 and the compensator 3, and the inner cylindrical fluid chamber 6 being defined by the interior of the inner sleeve 1a and by the piston 2 and the closure 4. As shown in Figure 1, when the closure 4 is in the open position, fluid can flow from the outer fluid chamber 5 to the inner fluid chamber 6 and vice versa.

[0021] The function of the locking system according to the present invention will be explained in more detail below with reference to Figures 2, 3, and 4. In Figure 2, the piston rod 2 is retracted significantly inward. Therefore, the inner fluid chamber 6 has a very small volume. The compensator 3 is located at the cap end of the cylinder 1, and the volume of the outer fluid chamber 6 is at its maximum. The closure 4 is in the open position. This means that fluid can flow back and forth between the fluid chambers 5 and 6. When a tensile force F is applied to the piston rod 2a, the piston 2 is displaced toward the cap end of the cylinder 1, as shown in Figure 2. Fluid flows from the outer fluid chamber 5 to the inner fluid chamber 6. The compensator 3 is displaced toward the base end of the cylinder 1. The volume of the outer fluid chamber 5 decreases accordingly, while the volume of the inner fluid chamber 6 increases by the same amount. The sum of the two volumes remains the same. The area between the compensator 3 and the cap 1c is filled with air. For this purpose, the threaded connection between the inner sleeve 1a and the outer sleeve 1b is designed to be air-permeable. However, it is also possible to provide the cap 1c with an opening that is particularly suitable for this purpose.

[0022] As soon as the piston rod 2a is in the desired position, the closure 4 is guided into the closed position by the control, and no further fluid flow is permitted between the two fluid chambers 5, 6. This system state is shown in Figure 4. Accordingly, the piston rod 2a can no longer move. The locking system according to the invention is now in a stationary state. The holding force under tensile load is now at most the evaporation pressure of the fluid.

[0023] Control of the closure 4 can be carried out via an active control command. However, it is also possible to realize control in a reset manner, for example via a return spring. In this embodiment, the closure 4 is normally held in the closed position by the restoring force of the spring. When the restoring force is overcome by the compressive load of the piston rod, the closure opens. If the piston 2 is moved in the direction of the cap 1c, the closure 4 must be opened by the described active control command.

[0024] FIG. 5 shows a 3D view of the closure 4. The closure 4 has a radially rising annular projection 4b on its outer periphery and a central projection 4c with a rounded conical tip. This shape allows the closure 4 to optimally fit the base end of the inner sleeve 1a. When the closure 4 is moved between the open and closed positions, a uniform flow gap with very uniform flow characteristics is created. By precisely adjusting the closure 4, the desired damping of the piston rod 2a's mobility can also be set. By shaping, the strength of the damping progresses substantially linearly depending on the gap width or the position of the respective closure. The damping can also be influenced by the viscosity of the fluid used.

[0025] The locking system according to the invention is overall characterized by a very simple and low-cost construction, which can be easily installed regardless of the installation position and which operates very precisely. [Explanation of symbols]

[0026] 1 cylinder 1a Inner sleeve 1b Outer sleeve 1c Cap 1d base 2 pistons 2a Piston rod 2b Piston seal 3 Compensation body 3a Seal 4 Closing part 4a Seal 4b Annular protrusion 4c Conical protrusion 5. Outer Fluid Chamber 6. Inner fluid chamber

Claims

1. 1. A continuously variable locking system for a cylinder-piston arrangement, comprising: a cylinder (1) having a cap (1c) and a base (1d); a piston (2) movably disposed within the cylinder (1) and having at least one annular piston seal (2a) circumferentially disposed on an outer surface thereof, the piston (2) having a piston rod (2b) disposed on the piston, the piston rod being at least partially axially pushed out at a cap end of the cylinder (1); a closure (4) continuously variable between an open and closed position; and a fluid disposed within the cylinder (1), The cylinder is formed with a double wall having an inner sleeve (1 a) and an outer sleeve (1 b), the piston (2) is arranged in the inner sleeve (1 a), a tubular compensator (3) having seals (3 a) running circumferentially on its inner and outer surfaces is displaceably arranged in the annular space between the inner sleeve (1 a) and the outer sleeve (1 b), the closure part is arranged at the end of the base (1 d) of the cylinder (1), and the base-side end of the inner sleeve (1 a) can be closed by the closure part (4), The closure (4) has an annular projection (4b) that increases in the axial direction on the outer periphery and a conical central projection (4c). A locking system characterized by:

2. 2. The method according to claim 1, characterized in that the control mechanism acting on the closure (4) is arranged outside the cylinder. Locking system.

3. 3. The locking system according to claim 1 or 2, characterized in that the inner sleeve (1a) and the outer sleeve (1b) are detachably connected to each other in a form-locking and / or force-locking manner.

4. 4. A locking system according to claim 3, characterized in that the inner sleeve (1a) and the outer sleeve (1b) are connectable to each other by means of corresponding threads.

5. Locking system according to any one of claims 1 to 4, characterized in that the closure (4) is formed as a body that is rotationally symmetrical with respect to the longitudinal axis of the cylinder (1).

6. 2. The locking system of claim 1, wherein the fluid is hydraulic oil.

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