Snap fastener

Abstract

The snap ring has a first end portion having a discontinuous band with first and second axial faces on opposite sides, a first end face, and a groove extending from the first end face and the opening to the first axial face, a second end face, and a second end portion having a tongue projecting from the second end face. The groove is U-shaped, the second axial face defines the base of the groove, the tongue is dimensioned to fit within the groove, and when the tongue is received within the groove, the first end portion is positioned relative to the second end portion and a continuous ring is formed. A method of assembling a snap ring within a circumferential groove in a component includes supplying the snap ring within the groove such that the end portions are adjacent to each other, axially distorting the second end portion from the plane of the groove, bringing the end portions closer to each other until the tongue overlays the groove, and inserting the tongue into the groove such that the end portions enter the groove.

Description

Technical Field

[0001] The present invention relates to a ring fastener such as a retaining ring and a method of incorporating the ring fastener into a groove of a component.

Background Art

[0002] Retaining rings can have many different applications and are often used when fixing components together, such as fixing two rotating components together. For example, the retaining ring can be fitted into a groove on the inner surface of a bore to act as a shoulder for mounting or fixing a component within the bore.

[0003] An example of a retaining ring is a helical retaining ring, which comprises a single wound band having a gap within the circumference of the ring. When attached, the two ends of the ring can come together and contact each other. However, during use, the thermal expansion of the ring can move the two ends of the ring apart, thus causing the gap to open. Therefore, this type of retaining ring does not provide reliable full - circumference support to the components during use.

[0004] Some retaining rings overcome this problem by providing a retaining ring with two or more turns. However, the material used to manufacture such rings is considerably thinner than that of a single - turn ring, and each such ring does not provide sufficient torsional rigidity. This can cause the ring to twist during use, potentially reducing the stability of the ring and its ability to effectively fix the components together.

[0005] WO2020 / 234572 describes a ring fastener including a discontinuous band having a first end and a second end. The first end includes a pair of spaced-apart elongate finger members (having a first finger member and a second finger member), and the second end includes an elongate tongue member. The finger members and the tongue member are interlockable such that when interlocked, the band has a continuous perimeter. The ring fastener further has a closed configuration in which the finger members and the tongue member are substantially aligned with the circumferential surface of the band, and an open configuration in which the first finger member is deflected radially and / or axially from its substantially aligned position such that it is angled with respect to the circumferential surface of the band. Summary of the Invention Problems to be Solved by the Invention

[0006] Accordingly, it is an object of the present invention to provide reliable full circumference support during use while maintaining a stable and effective connection between two components with a relatively simple and robust structure. Means for Solving the Problems

[0007] A first aspect of the present invention is a ring fastener, comprising: a discontinuous band having first and second axial faces on opposite sides; a first end including a first end face and a groove extending from the first end face and the opening to the first axial face; and a second end including a second end face and a tongue protruding from the second end face, wherein the tongue is dimensioned to fit within the groove, and when the tongue is received within the groove, the first end is positioned relative to the second end such that a continuous ring is formed.

[0008] The arrangement of the tongue and the groove is relatively robust and can be assembled and disassembled by distorting the ring to engage or disengage the tongue and the groove.

[0009] The groove can be U-shaped, and the second axial surface defines the base of the groove.

[0010] The axial thickness of the tongue can be substantially the same as the axial depth of the groove. Thereby, the surface of the tongue can be substantially flush with the first axial surface of the ring at the first end. This can avoid protruding portions that may catch or interfere with other components during use. The tongue may extend from the first axial surface of the second end or may be recessed from the second axial surface of the second end. Thereby, the first and second axial surfaces of the first and second ends can be aligned and flush.

[0011] The tongue can have parallel radial side surfaces and a terminal end face. The tongue can have an edge with an angle between one of the radial side surfaces and the terminal end. This can assist in inserting the tongue into the groove.

[0012] The length of the groove from the first end face can be greater than the length of the tongue extending from the second end face. This can avoid the end face of the tongue contacting the end of the groove and avoid causing distortion or damage to one and / or the other of the groove and the tongue.

[0013] When inserting the tongue into the groove, the first and second end faces can be separated. This allows for some relative movement of the end faces due to thermal expansion or contraction or other forces.

[0014] Another feature of the present invention is a method of incorporating a ring fastener into a circumferential groove of a component, the method including the following steps: Placing the ring fastener into the circumferential groove such that the first end and the second end are adjacent to each other; Distorting the second end that is axially offset from the plane of the circumferential groove; Moving the first end and the second end closer to each other until the tongue overlaps the groove, and inserting the tongue into the groove such that the first end and the second end are within the circumferential groove of the component. [Brief explanation of the drawings]

[0015]

Figure 1

Figure 2

Figure 3

[0016] The ring fastener shown in the drawings is essentially circular, with only a portion of the ring being shown in the drawings.

[0017] The ring fastener shown in the drawings is typical of fasteners used in turbines, such as gas turbines, to secure components within bores. The fastener is fabricated from an alloy having suitable high temperature strength and oxidation resistance.

[0018] The fastener is formed from a metal strip 10 having a generally rectangular cross section with rounded corners. The strip has an axial surface and a radial surface.

[0019] The strip does not form a complete circle, but instead has discontinuous, opposing end faces 12,14.

[0020] The first end 16 of the strip 10 defines a groove 18 extending from an open end 20 of the first end face 12 and opening onto one of the axial surfaces 22. The other axial surface 24 defines the base of the groove 18, which is essentially U-shaped, and the radial sides of the strips 26, 28 define the sides of the groove 18. The closed end 30 of the groove 18 has an arcuate shape.

[0021] At the second end 32 of the strip 10, a tongue 34 protruding from the second end face 14 is formed. The tongue 34 has a substantially straight side surface and a square end face 36. There is an angled edge 38 between one side 40 and the end face 36. The tongue 34 is narrower than the width of the strip 10 and is dimensioned to fit into the groove 18.

[0022] The tongue 34 is offset to one side of the second end 32 such that one surface 42 thereof is flush with the axial surface 22 of the strip 10. The other surface 44 of the tongue is recessed from the opposite axial surface 24 of the strip 10. The thickness of the tongue 34 is substantially the same as the depth of the groove 18 such that when the tongue 34 is seated in the groove 18, its surface 42 is substantially in the same plane as the axial surface 22 of the first end 16.

[0023] In use, one end of the strip 10 is to be fed into a groove of a component such as a circumferential groove (not shown), and the strip 10 is fed around the component until the two ends 16, 32 approach each other. At this point, the second end 32 with the tongue 34 can be bent away from the circumferential surface and forced to be positioned over the first end 16 with the groove 18. Then, the tongue 34 can be biased into the groove 18, and the angled edge 38 allows the tongue 34 to clear the side of the groove 18. At this point, a portion of the tongue 34 is seated in the groove 18 and the ring fastener presents a complete circumference, but the end faces 12, 14 are spaced apart by a small distance. The length of the tongue 34 is such that even when the tongue 34 is fully inserted into the groove 18 and the end faces 12, 14 are in contact with each other, the end face 36 of the tongue 34 does not contact the closed end 30 of the groove 18. The space between the end faces 12, 14 allows for adjustment of expansion or contraction due to temperature changes without displacing the ring from the groove.

[0024] Holes 46, 48 are provided in strip surface 22 near each end 16, 32 to enable the use of an assembly tool (not shown) to manipulate ends 16, 32 of strip 10, such that tongue 34 can be placed in or removed from groove 18.

[0025] The present invention has been described above with reference to one specific embodiment. Various changes or modifications can be made without departing from the scope of the present invention.

Claims

1. Ring fasteners are a discontinuity strip having a first axial surface and a second axial surface on opposite sides; a first end having a first end surface and a U-shaped groove extending from the first end surface and an opening to a first axial surface, the second axial surface defining a base of the groove; a second end having a second end surface and a tongue projecting from the second end surface; the tongue is sized to fit into the groove; When the tongue is received in the groove, the first end rests against the second end to form a continuous ring.

2. 2. The ring fastener according to claim 1, wherein the axial thickness of said tongue is the same as the axial depth of said groove.

3. 3. A ring fastener according to claim 1 or claim 2, wherein the tongue extends from the first axial face of the second end.

4. 4. A ring fastener according to claim 3, wherein said tongue is recessed from the second axial face of said second end.

5. 3. A ring fastener according to claim 1 or claim 2, wherein the tongue has parallel radial sides and terminal faces.

6. 3. A ring fastener according to claim 1 or claim 2, wherein the tongue comprises an angled edge between one of the radial flanks and the terminal face.

7. 3. The ring fastener according to claim 1, wherein the length of the groove from the first end face is greater than the length of the tongue extending from the second end face.

8. 3. A ring fastener according to claim 1 or claim 2, wherein the first end face and the second end face are spaced apart when the tongue is received in the groove.

9. 3. A method for assembling a ring fastener according to claim 1 or claim 2 into a circumferential groove of a part, said method comprising the steps of: placing the ring fastener in the circumferential groove so that the first end and the second end are adjacent one another; distorting the second end axially out of plane of the circumferential groove; moving the first end and the second end toward each other until the tongue overlaps the groove, and inserting the tongue into the groove so that the first end and the second end are within the circumferential groove of the part.

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