Automatic center buffer coupling for rail vehicles and coupling assembly composed thereof

Description

[0001] The present invention relates to an automatic center buffer coupling for rail vehicles with a Scharfenberg-type coupling head with a coupling head housing and coupling locking means arranged therein, comprising a main bolt, a coupling eye, a coupling eye bolt, and a frog. Furthermore, the invention also relates to a coupling arrangement consisting of two interconnected center buffer couplings of the aforementioned type.

[0002] The field of application of the invention extends to rail vehicle technology. The central buffer couplings of interest here are used to couple individual wagons or partial trains together. These couplings, arranged in the area of ​​the wagon's longitudinal axis, represent a combination of buffer and coupling. Specifically, the present invention relates to a technical improvement of a Scharfenberg-type central buffer coupling. The interconnected coupling heads form a rigid connection to enable the coupling of electrical and / or pneumatic connections. To compensate for relative movements between the coupled wagons, the couplings are usually mounted in the vehicle underframe and are pivotably mounted vertically and horizontally via their linkage.In this arrangement, compressive forces are transmitted via the coupling head housings that come into contact with each other, whereas the tensile forces are also transmitted via the internal coupling locking means. State of the art

[0003] CH 39226 describes a generic Scharfenberg-type central buffer coupling. Each of the coupling head housings of a coupling arrangement with two corresponding central buffer couplings is equipped with a cone and a funnel, which are joined to the complementary parts of the mating coupling during coupling, thus aligning both coupling heads. A coupling eye protrudes from an opening in the cone and, during coupling, engages with the cone into the funnel of the mating coupling. A main bolt is attached to the coupling head housing, on which a hook disc—the so-called frog—is rotatably mounted. The frog carries a coupling eye pin around which the coupling eye rotates. The frog contains a hook mouth in the form of an open slot. The center axis of its rounded surface is offset by 180° on the same radius as the coupling eye pin relative to the main bolt.This is necessary because if the coupling eye bolt and hook mouth had different radii, the frogs connected by the coupling eyes would block each other and no movement would be possible. The movement of the coupling eye bolt of one frog through an angle must be counteracted by the same angular movement of the other frog. During the coupling process, one or more tension springs pull the frog against a stop surface on the coupler head housing into a coupled position. During coupling, the coupling eye engages with the hook mouth of the mating coupling. The opening in the cone of the coupling housing is provided with limiting surfaces within which the coupling eye can move. When two coupling heads move together, both coupling eyes meet the respective frog of the opposite coupling with this state of the art.As they move further together, the coupling eyes rotate their frogs against the force of the respective tension spring. This causes the coupling eyes to slide into the corresponding hook mouth of the frog, so that the funnel and cone of both couplings are joined together in the engaged position. Due to the spring forces acting on them, the coupling eyes and frogs rotate to their stops, moving the coupling eyes into the engaged position.

[0004] The new standard DIN EN 16019 provides a standardized, current design based on the aforementioned original coupling principle. When engaged, the coupling locking devices form a force parallelogram within which the tensile forces are evenly distributed across both locking strands. This balance of forces prevents accidental opening of the locked coupling locking devices. While the compressive forces are transmitted via the flat end surfaces of the coupling head housing, the tensile forces are transmitted via the aforementioned force parallelogram of the coupling locking devices. According to the standard, the coupling head must be designed for a tensile force of 1,000 kN and a compressive force of 1,500 kN, which applies under normal operating conditions.

[0005] If the compressive force exerted on the coupling assembly during operation exceeds the aforementioned load value, this generally does not lead to immediate damage due to the stable housing structure. However, if the tensile force exceeds the aforementioned load value, uncontrolled component failure can occur. The frog is usually the weakest component, failing at approximately 2,200 kN due to its design. This results in irreparable damage due to plastic deformation, including in adjacent components of the coupling locking device.

[0006] It is therefore the object of the present invention to further improve an automatic central buffer coupling of the generic type in such a way that an excessive tensile load causes a repairable component failure and leads to a controlled separation of the central buffer coupling and occurring compressive loads have no influence on this mechanism. Brief description of the invention

[0007] The problem is solved based on an automatic central buffer coupling according to the preamble of claim 1 in conjunction with its characterizing features. With regard to a coupling arrangement consisting of two such central buffer couplings, the problem is solved by claim 8. The respective dependent claims specify advantageous developments of the invention.

[0008] The invention includes the technical teaching that, for the safe release of a coupling connection when an overloading response force FA in the tensile direction is exceeded, the coupling eye bolt of the coupling locking means is designed as a shear bolt. Thus, the inventive measure is directed toward the specification and modification of a specific component of the coupling locking means integrated into the coupling force flow, in this case the coupling eye bolt. The remaining components, in particular the main bolt, the coupling eye, the centerpiece, and the coupling head housing, can remain unchanged. Thus, the inventive solution is also suitable for retrofitting existing Scharfenberg-type coupling heads.

[0009] The inventive solution is based on the fact that the load paths for compressive and tensile forces are different in the area of ​​the coupling head. The coupling locking means, essentially consisting of the main bolt, coupling eye, coupling eye bolt and frog, transmit the tensile forces in a sequence that matches the force flow, with only the coupling eye bolt being equipped with at least one predetermined breaking point. This allows the coupling eye bolt to fail in a controlled manner from a critical shear load corresponding to an assigned response force FA, thereby releasing the coupling connection. The specific design as a shear bolt allows the response force FA to be dimensioned relatively precisely, thus ensuring reliable function. If a coupling eye bolt fails due to overload, the tensile forces are no longer transmitted equally via both coupling eyes of the coupling arrangement, but only via one coupling eye.The equilibrium of forces in the parallelogram of the coupled closure elements is no longer present. As a result, one of the two coupling closures unscrews and rotates into the open position. This results in the intended separation of the coupling assembly.

[0010] The solution according to the invention ensures that no stress is placed on the coupling eye bolts when the coupling assembly is subjected to compressive loads, so that the coupling assembly advantageously only reacts to excessive tensile loads. Furthermore, the fragments generated during a controlled component failure of the coupling eye bolt cannot fall off but remain in the coupling head housing. The coupling eye bolts modified according to the invention are the only parts that need to be replaced after a safety release, thus enabling easy repair of the central buffer coupling.

[0011] According to a preferred embodiment of the solution according to the invention, the coupling eye bolt extending between a forked end-shaped coupling eye and a part of the center piece engaging therein is provided with at least one circumferential notch as a predetermined breaking point. This outer circumferential predetermined breaking point forms the shear pin according to the invention. The at least one circumferential notch preferably has an acute-angled notch cross-section, which can be easily produced by machining a prefabricated metal bolt. The notch cross-section can also be provided with radii. For manufacturing reasons, the at least one circumferential notch preferably extends over the entire circumference of the coupling eye bolt. However, it is also conceivable to only introduce a section-by-section notch as a predetermined breaking point.

[0012] According to a particularly preferred embodiment, the coupling eye bolt is provided with precisely two circumferential notches that are arranged at an axial distance from one another that corresponds to the corresponding boundary area between the frog and the forked coupling eye. This creates two predetermined breaking points located at the point of shear force action, which enable a particularly defined component failure because the circumferential notches run in the shear planes between the coupling eye and the frog. This allows for application-specific adjustment of the response force FA . The coupling eye bolt is preferably designed like a round bolt that is secured in the assembly position with a snap ring at the distal end. This enables simple assembly and disassembly in a functionally correct position.

[0013] According to another measure further improving the invention, the coupling eye bolt, designed as a shear pin, is provided with at least one internal lubrication channel, which conducts lubricating oil or grease from the end face of the coupling eye bolt to the outer surface for lubricating the joint connection between the coupling eye and the frog. Since the lubrication channels are internal and do not impair the position and design of the circumferential notches, the shear function can be combined with the lubrication function without mutual interference.

[0014] The two central buffer couplings described above can be combined to form a coupling arrangement, with the associated coupling eye bolts interacting within the parallelogram locking mechanism in such a way that the coupling arrangement releases when a response force FA in the direction of pull is exceeded, which, depending on the application and design of the coupling, is in the range between 200 and 2,000 kN, preferably 1,500 kN + 15%. This is because the solution according to the invention can be dimensioned for both low and very high tensile forces.

[0015] Preferably, both coupling heads of a coupling assembly are each equipped with a coupling eye bolt designed as a shear bolt. If a response force FA of 1,500 kN is to be achieved, this corresponds to a response force of 750 kN for each bolt, assuming an even distribution of the loads in the force parallelogram. Detailed description based on drawing

[0016] Further measures improving the invention are described in more detail below, together with the description of a preferred embodiment of the invention, with reference to the figures. It shows: Fig. 1 shows a partial longitudinal section through a coupling head of an automatic central buffer coupling, Fig. 2 shows a coupling arrangement composed of two coupled coupling heads, and Fig. 3 shows a longitudinal section through the coupling locking means in the area of ​​the coupling eye bolt.

[0017] According to Fig. 1 A coupling head 1 of an automatic central buffer coupling for a rail vehicle (not shown here) constructed according to the Scharfenberg design essentially consists of a front-side funnel 2 for receiving a cone 6 of the corresponding coupling head (not shown here), which is formed on a coupling head housing 9.

[0018] The coupling head housing 9 houses mechanical coupling locking means, comprising a main pin 3 for pivotally supporting a frog 4 with a hook mouth on the funnel side. A coupling eye 5 is hinged to the frog 4 by means of a coupling eye pin 8, the distal end of which is arranged in the region of the cone 6 to form a pull rod. The frog 4 is rotated into a coupled position via one or more tension springs 7, and the respective release mechanism of the exemplary 2-position lock is pressed by the cone of a coupling that extends into the funnel of a mating coupling.

[0019] The dome closure means comprise a spring bearing 10 as a release mechanism, which acts on a release plunger 11 with a ratchet rod extending therefrom. In designs with a 2-position closure, this release mechanism serves to release the dome closure from its pre-tensioned, ready-to-engage position, allowing it to rotate into the engaged position under the force of the tension springs.

[0020] The Fig. 2 shows two of the coupling heads 1 and 1' described above, each with internally located, corresponding coupling locking means for forming a coupled coupling arrangement. Here, both coupling eye bolts 8 and 8' are designed as shear bolts.

[0021] According to Fig. 3the coupling eye bolt 8, which runs between a coupling eye 5 which is fork-shaped at the end and the part of the frog 4 which engages therein, is provided with two circumferential notches 12a and 12b which are arranged axially spaced from one another and which give the coupling eye bolt 8 the property of a shear bolt in order to bring about a safe release of the coupling connection when a response force FA which can be determined via the dimensioning of the interacting components is exceeded.

[0022] In this embodiment, the coupling eye bolt 8 is designed like a collar bolt and is secured in the assembly position at the distal end with a snap ring 13. Furthermore, in this embodiment, the coupling eye bolt 8 is traversed by an internal lubrication channel 14, from which at least a transverse section branches off, for lubricating the articulated connection between the coupling eye 5 and the center piece 4, for example, via a front-end lubrication nipple.

[0023] The solution according to the invention is not limited to the preferred embodiment described above. Rather, modifications thereof can also be implemented, which are also encompassed by the scope of the following claims. For example, it is also possible to provide a single circumferential notch or other component-weakening structures as a predetermined breaking point if, for example, the articulated components, the centerpiece 4 and the coupling eye 5, are not connected to each other via a fork connection. List of reference symbols

[0024] 1Coupling head 2Funnel 3Main bolt 4Face 5Coupling eye 6Cone 7Tension spring 8Coupling eye bolt 9Coupling head housing 10Spring bearing 11Trigger unit 12Circumferential notch 13Retaining ring 14Lubrication channel

Claims

1. Automatic central buffer coupling for rail vehicles with a coupling head (1) according to a Scharfenberg construction with a coupling head housing (9) and a coupling closure means arranged therein, comprising a main bolt (3), a coupling eye (5), a coupling eye bolt (8) and a heart piece (4), characterized in that for safety-release of a coupling connection after exceeding a response force (FA) in pull direction the coupling eye bolt (8; 8') of the coupling closure means is designed as a shear pin.

2. Automatic central buffer coupling according to Claim 1, characterized in that the coupling eye bolt (8; 8') extending between a fork-shaped coupling eye (5) and a part of the heart piece (4) coming into engagement herein is equipped with at least one peripheral groove (12a, 12b) as a predetermined breaking point.

3. Automatic central buffer coupling according to Claim 2, characterized in that the at least one peripheral groove (12a, 12b) has an acute-angled groove cross-section.

4. Automatic central buffer coupling according to Claim 2 or 3, characterized in that the at least one peripheral groove (12a, 12b) extends across the entire peripheral circle of the coupling eye bolt (8; 8').

5. Automatic central buffer coupling according to Claim 2, characterized in that the coupling eye bolt (8; 8') is equipped with precisely two peripheral grooves (12a, 12b) which are arranged at an axial distance to one another in the border region, corresponding thereto, between heart piece (4) and fork-shaped coupling eye (5), in order to form two assigned predetermined breaking points in the regions of the coupling eye bolt (8; 8') exposed to shearing forces.

6. Automatic central buffer coupling according to any one of Claims 1 to 5, <b>characterized in that the coupling release bolt (8; 8') is designed in the manner of a collar bolt, which at the distal end side is secured with a retaining ring (13) in the assembly position.

7. Automatic central buffer coupling according to any one of claims 1 to 6, characterized in that the coupling eye bolt (8; 8') designed as a shear pin is crossed with at least one inlying lubrication duct (14) which conducts lubrication oil or lubricating fat from an end face of the coupling eye bolt (8; 8') to the outer lateral surface for lubrication of the joint connection between coupling eye (5) and heart piece (4).

8. Coupling assembly consisting of two central buffer couplings connected to one another with coupling heads (1, 1') in a Scharfenberg construction corresponding to one another, of which at least one of the two central buffer couplings is designed according to any of the preceding claims.

9. Coupling assembly according to claim 8, characterized in that the respectively assigned coupling eye bolts (8, 8') interact together in the context of a parallelogram closure such that the coupling assembly releases when the response force is exceeded in pull direction which, depending on application, lies in the range between 200 to 2,000 kN, preferably at 1,500 kN +15%.

10. Coupling assembly according to claim 8 or 9, characterized in that both coupling heads (1, 1') are equipped with coupling eye bolts (8, 8') configured as shear pins.