Piston assemblies, and related components and systems

Abstract

The piston assembly includes a piston head. The piston assembly further includes an upper connecting rod rotatably coupled to the piston head. The piston assembly further includes a shoe disposed between the upper connecting rod and the inner wall of the piston head.

Description

Technical Field

[0004] , , , ,

[0001] Priority Claim This application claims the benefit of U.S. Provisional Patent Application No. 63 / 368,183, filed Jul. 12, 2022, entitled "PISTON ASSEMBLY AND ASSOCIATED COMPONENTS, SYSTEMS, AND METHOD", the entire disclosure of which is incorporated herein by reference, under 35 U.S.C. § 119(e).

[0002] The present disclosure relates to internal combustion engines, and more particularly to piston assemblies for use within an engine and for connecting a piston head to the crankshaft of the engine.

Background Art

[0003] Conventional internal combustion engines of the type found in many current vehicles have a plurality of pistons each movably disposed within a plurality of cylinders formed within an engine block. Each piston is connected to a piston rod at a first end of the piston rod, and the piston rod is coupled to a crankshaft at a second end of the piston rod. Further, when a spark plug within the engine block fires to ignite a fuel mixture, the piston is driven downward to rotate the crankshaft, ultimately driving the entire vehicle. In a typical engine, a single connecting rod is used, connected to the corresponding piston at each first end and to the corresponding portion of the crankshaft at each second end. The connection points between both ends of each connecting rod and the corresponding piston and corresponding crankshaft are disposed at the ends of the longitudinal central axis of each connecting rod.

Summary of the Invention

Means for Solving the Problems

[0004] Embodiments of the present disclosure include a piston assembly. The piston assembly includes a piston head. The piston assembly further includes an upper connecting rod rotatably coupled to the piston head. The piston assembly further includes a shoe positioned between the upper connecting rod and the inner wall of the piston head.

[0005] Another embodiment of the present disclosure includes an engine. The engine includes a cylinder, a crankshaft, and a piston assembly disposed within the cylinder. The piston assembly includes a piston head. The piston assembly further includes an upper connecting rod rotatably coupled to the piston head. The piston assembly further includes a lower connecting rod coupled between the upper connecting rod and the crankshaft. The piston assembly further includes a shoe slidably coupled between the upper connecting rod and the skirt of the piston head.

[0006] Another embodiment of the present disclosure includes an upper connecting rod of a piston assembly. The upper connecting rod includes a piston connection point. The upper connecting rod further includes a lower rod connection point. The upper connecting rod further includes a curved recess defined within the outer edge of the upper connecting rod. The curved recess is configured to receive an interface element between the upper connecting rod and the piston. The curved recess is positioned closer to the piston connection point than to the lower rod connection point.

[0007] This specification concludes with claims that specifically and clearly define embodiments of the present disclosure, but the advantages of embodiments of the present disclosure can be more readily identified from the following description of embodiments of the present disclosure when read in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing a piston assembly located inside an engine according to one or more embodiments of the present disclosure. [Figure 2]This figure shows a piston head assembly according to one or more embodiments of the present disclosure. [Figure 3] This figure shows a piston head assembly according to one or more embodiments of the present disclosure. [Figure 4] This figure shows a piston head assembly according to one or more embodiments of the present disclosure. [Figure 5] Figures 2-4 show perspective views of the piston head assembly shoe according to one or more embodiments of the present disclosure. [Figure 6] These are side views showing the upper connecting rod of the piston head assembly shown in Figures 2-4, according to one or more embodiments of the present disclosure. [Modes for carrying out the invention]

[0009] The figures presented herein are not actual diagrams of any internal combustion engine system, piston assembly, or any component thereof, but are merely idealized diagrams used to illustrate embodiments of the present disclosure.

[0010] As used herein, singular nouns following “a,” “an,” and “the” are intended to include plural nouns unless the context clearly indicates a different meaning.

[0011] The term “may” as used herein in relation to the conduct of materials, structures, features, or methods indicates that the conduct of these materials, structures, features, or methods is intended to be used in implementations of embodiments of the present disclosure, and is preferred over the more restrictive word “is” to avoid any implicit implication that other compatible materials, structures, features, and methods that may be used in combination with these materials, structures, features, or methods should or must be excluded.

[0012] Any relational terms used herein, such as “first,” “second,” “top,” “bottom,” “upper,” and “lower,” are used to clearly and conveniently understand this disclosure and the accompanying drawings, and do not imply, nor depend on, any specific priority or order, unless the context clearly indicates otherwise. For example, these terms may mean the orientation of a piston assembly or engine element in a conventional orientation. Furthermore, these terms may mean the orientation of a piston assembly or engine element as shown in the drawings.

[0013] As used herein, the term “substantially” means, and includes, the degree to which a given parameter, characteristic, or condition is subject to minor changes within the range of acceptable manufacturing tolerances, etc., as understood by a person skilled in the art. For example, depending on the specific parameter, characteristic, or condition that substantially conforms, the parameter, characteristic, or condition may conform to at least 90.0%, at least 95.0%, at least 99.0%, or at least 99.9%.

[0014] As used herein in reference to a given parameter, the term "approximately" includes the stated value and has a meaning determined by the context (e.g., including any error associated with the measurement of the given parameter).

[0015] Figure 1 shows a schematic diagram of a piston assembly 100 located within an engine 102. The piston assembly 100 may include a piston head 104, an upper rod 106, a gadion pin assembly 107 (e.g., two or more pin locks, needle sleeve bearings, and gadion pins (e.g., wrist pins)), a lower rod 108, and a connector pin assembly 109. The engine 102 may include a cylinder 112, one or more valves 114 and exhaust ports 116 (e.g., an intake valve and intake port, and an exhaust valve and exhaust port), and a fuel injector 118. One or more valves 114 and exhaust ports 116 of the engine 102 may be oriented in a conventional manner.

[0016] The piston head 104 of the piston assembly 100 may be positioned within the cylinder 112 of the engine 102 and may be configured to reciprocate back and forth (for example, up and down as shown in Figure 1) during use. The upper rod 106 may be coupled to the piston head 104 at a first longitudinal end of the upper rod 106 via a gadion pin assembly 107, and to the lower rod 108 at a second opposite longitudinal end of the upper rod 106. In some embodiments, the upper rod 106 may be coupled to the piston head 104 near the piston head 104 or at its center of mass. In one or more embodiments, the upper rod 106 may be coupled to the piston head 104 at a point located centered between the upper and lower surfaces of the piston head 104 and intersecting the longitudinal central axis 122 of the piston head 104. In one or more embodiments, the longitudinal axis 120 of the gadion pin assembly 107 may extend perpendicular to the longitudinal axis 122 of the piston head 104, or it may intersect with the longitudinal axis 122 of the piston head 104. The upper rod 106 may be configured not to rotate and / or translate relative to the piston head 104 during use.

[0017] The upper rod 106 may extend axially (for example, in a direction parallel to the longitudinal axis 122 of the piston head 104) from the piston head 104 to a region below the piston head 104 (for example, below the piston head 104 as depicted in Figure 1). For example, the longitudinal length of the upper rod 106 may be greater than the distance from the point where the upper rod 106 is connected to the piston head 104 to the lowest surface of the piston head 104. Furthermore, the longitudinal axis of the upper rod 106 may be parallel to the longitudinal axis 122 of the piston head 104. Considering the above, when the upper rod 106 is connected to the piston head 104, the lower longitudinal end of the upper rod 106 may be oriented below the piston head 104.

[0018] As described above, the upper rod 106 may be coupled to the lower rod 108 at the longitudinal end opposite the piston head 104 (i.e., the lower longitudinal end of the upper rod 106). In some embodiments, the upper rod 106 may be coupled to the lower rod 108 via a connector pin assembly 109. In one or more embodiments, the connector pin assembly 109 may have any gadion pins and / or wrist pins and associated assemblies known in the art.

[0019] The lower rod 108 may be rotatable with respect to the upper rod 106. For example, the lower rod 108 may be configured to pivot around the connector pin assembly 109 and the upper rod 106. For example, the connector pin assembly 109 may provide a bearing, and when the piston assembly 100 repeatedly performs multiple strokes (described later), the lower rod 108 can pivot around this bearing.

[0020] The lower rod 108 can be coupled to the crankshaft 126 at the longitudinal end of the lower rod 108 on the opposite side of the upper rod 106. The crankshaft 126 can include a conventional crankshaft. For example, the crankshaft 126 can convert the reciprocating motion of the piston head 104 into rotational motion. As is known in the art, a crankshaft has a plurality of "crank throws" or "crank pins", and a plurality of bearing surfaces (e.g., rod journals, connecting rod journals, etc.) having an axis offset from the longitudinal central axis 128 of the crankshaft 126. The lower rod 108 can be coupled to each bearing surface of the crankshaft 126. In addition, the lower rod 108 can be coupled to the crankshaft 126 via any conventional bearing. Further, as will be appreciated by those skilled in the art, the rotational axis 128 (i.e., the longitudinal central axis) of the crankshaft 126 may be parallel to the longitudinal axis 124 of the connector pin assembly 109.

[0021] To describe the operation of the piston assembly 100, the normal clock face time positions are herein cited as the positions of the lower longitudinal end of the lower rod 108 centered about the rotational axis 128 of the crankshaft 126 (e.g., 1 o'clock, 3 o'clock, etc.). For example, the above positions can mean the center point of the lower longitudinal end of the lower rod 108 and its position based on the rotational axis 128 of the crankshaft 126 as depicted in FIG. In this case, regardless of the orientation of the associated engine and / or cylinder, the piston head 104 associated with the lower rod 108 is at top dead center at the 12 o'clock position and bottom dead center at the 6 o'clock position.

[0022] In some embodiments, the engine 102 and the piston assembly 100 can include a four-stroke engine. For example, in use, the piston assembly 100 can complete four separate strokes while rotating the crankshaft 126. In other words, the engine 102 and the piston assembly 100 can repeatedly perform a typical four-stroke cycle.

[0023] The piston assembly 100 can initiate a four-stroke cycle with an intake stroke (e.g., induction stroke or suction stroke). The intake stroke begins with the piston head 104 positioned at top dead center and ends with the piston head 104 positioned at bottom dead center, as is known in the art. During the intake stroke, the intake valve (e.g., valve 114) opens (by the breaker cam lobe of the breaker cam, as is known in the art), and as the piston head 104 moves downward within the cylinder 112, the piston head 104 draws an air mixture into the cylinder 112 by generating a vacuum pressure within the cylinder 112 through the downward motion of the piston head 104. In addition, the fuel injector 118 injects fuel into the air to form an air-fuel mixture. As described above, the piston assembly 100 of this disclosure can reduce the force required to move the piston head 104 from the 12 o'clock position to the 6 o'clock position, and as a result, some of the energy required to perform the intake stroke can be saved (for example, energy from other piston assemblies that rotate the crankshaft 126 during the power stroke (i.e., the combustion stroke) of other piston assemblies). As will be recognized by those skilled in the art, reducing the amount of energy required to perform the intake stroke increases the energy available for other operations of the engine 102 (for example, when using the engine 102 to operate a vehicle). Therefore, the piston assembly 100 of this disclosure can provide a more efficient engine compared to conventional piston assemblies.

[0024] After the intake stroke, the piston assembly 100 starts the compression stroke. The compression stroke starts at the piston head 104 disposed at the bottom dead center and ends at the piston head 104 disposed at the top dead center. During the compression stroke, the piston head 104 compresses the air-fuel mixture in preparation for ignition during the power stroke (described later). Further, during the compression stroke, the intake valve and the exhaust valve (e.g., valve 114) are closed. As described above, the piston assembly 100 of the present disclosure reduces the force required to move the piston head 104 from the 6 o'clock position to the 12 o'clock position, and as a result, a part of the energy required during the compression stroke can be saved. As will be appreciated by those skilled in the art, reducing the amount of energy required to perform the compression stroke increases the energy available for other operations of the engine 102.

[0025] When the air-fuel mixture is compressed and reaches the top dead center, the piston assembly 100 can initiate the power stroke (i.e., the combustion stroke or the ignition stroke). When the piston head 104 is near the top dead center, the air-fuel mixture is ignited by an initiator (e.g., a spark plug, a glow plug, etc.) or by the heat generated by high compression (e.g., a diesel engine). Igniting the air-fuel mixture causes an explosion, and this explosion forcibly returns the piston head 104 to the bottom dead center. As is known in the art, the power stroke creates a mechanical action from the engine 102 for rotating the crankshaft 126. For example, the power stroke can create a mechanical action through a conventional method that involves the piston assembly and the crankshaft.

[0026] As described above, the piston assembly 100 of the present disclosure reduces the force required to move the piston head 104 from the 6 o'clock position or the 12 o'clock position. As a result, the piston assembly of the present disclosure allows the air-fuel mixture to ignite closer to or at the 12 o'clock position compared to conventional piston assemblies. For example, conventional piston assemblies typically have an ignition position between the 10 o'clock and 12 o'clock positions, thereby providing the force required to rotate through the 12 o'clock position. Furthermore, as will be understood by those skilled in the art, igniting the air-fuel mixture closer to or at the 12 o'clock position (and not at a significantly earlier timing) makes it possible to increase the pressure generated by the ignition that acts on the piston assembly to move the piston assembly downward in the power stroke.

[0027] Upon reaching bottom dead center, the piston assembly 100 begins its exhaust stroke. During the exhaust stroke, the piston head 104 of the piston assembly 100 returns from bottom dead center to top dead center, where the exhaust valve (e.g., valve 114) is open. The action of the piston head 104 moving from bottom dead center to top dead center expels the spent air-fuel mixture through the exhaust port 116, passing through the exhaust valve 114. Furthermore, upon reaching top dead center, the piston assembly 100 can repeat the four strokes described above.

[0028] During various strokes, forces transmitted through the upper rod 106 and lower rod 108 can introduce longitudinal forces along the longitudinal central axis 122 and lateral forces perpendicular to the longitudinal central axis 122. The longitudinal forces can act to move the piston head 104 along the longitudinal central axis 122 within the cylinder 112. The lateral forces can generate a moment on the piston head 104 through a moment arm created by the upper rod 106. The piston head 104 may include a skirt 130 configured to substantially prevent the piston head 104 from tilting or vibrating (rocking) within the cylinder 112. However, the skirt 130 can come into contact with the walls of the cylinder 112, creating additional friction. Therefore, additional structures configured to counteract the lateral forces and / or reduce the moment arm created by the upper rod 106 can reduce frictional forces and improve the efficiency of the associated engine 102.

[0029] Figures 2-4 show various diagrams of the piston head 104, including a shoe 202 coupled between the upper rod 106 and the skirt 130 of the piston head 104. The shoe 202 may be configured to change the moment arm of the upper rod 106 relative to the piston head 104, thereby reducing the lateral force transmitted to the piston head 104 by the upper rod 106. For example, the shoe 202 may include a skirt interface 204 and a rod interface 302. Each of the skirt interface 204 and the rod interface 302 may be a sliding connection, as a result allowing the shoe 202 to move relative to the skirt 130 and the upper rod 106. The sliding connection can facilitate a slight rotation of the upper rod 106 relative to the piston head 104. For example, the rod interface 302 may form a fulcrum point, allowing the upper rod 106 to rotate slightly around the fulcrum point. Lateral forces within the upper rod 106 can be transmitted to the skirt 130 through the shoe 202. A second opposing force can be applied to the piston connection point 304 by the fulcrum created by the rod interface 302 between the shoe 202 and the upper rod 106. The lateral forces within the shoe 202 and at the piston connection point 304 can each be applied to the piston head 104 at various positions on the same side of the piston head 104 with respect to the axis of rotation of the piston head 104. Thus, opposing lateral forces can generate opposing moments on the piston head 104, significantly reducing the moment experienced by the piston head 104.

[0030] Figure 5 shows an embodiment of the shoe 202. As shown, the skirt interface 204 can have a greater width than the rod interface 302. The greater width of the rod interface 302 can increase the surface area of ​​the skirt interface 204 compared to the rod interface 302. The relatively larger surface area of ​​the skirt interface 204 can reduce the pressure generated by lateral forces, thereby reducing the pressure generated on the skirt 130 (Figures 2-4) by the skirt interface 204. Reducing the pressure on the skirt 130 (Figures 2-4) can facilitate the formation of the skirt 130 from a thinner material, thereby reducing the weight of the piston head 104.

[0031] The skirt interface 204 may have a radius that substantially matches the radius of the inner surface of the associated skirt 130 (Figures 2-4). This radius can facilitate the substantially uniform distribution of lateral forces on the associated skirt 130 (Figures 2-4) by the shoe 202. By distributing the forces, localized pressure on the inner surface of the skirt 130 (Figures 2-4) can be reduced, thereby facilitating the formation of the skirt 130 from thinner material, as well as increasing the surface area of ​​the skirt interface 204.

[0032] Figure 6 shows a side view of the upper rod 106. The upper rod 106 includes a piston connection point 304 and a lower rod connection point 604. The upper rod 106 may further include a recess 602 configured to interface with the rod interface 302 of the associated shoe 202. The recess 602 may have a curved surface that is complementary to the rod interface 302 of the associated shoe 202. The curved surface of the recess 602 may define an arc having an angle greater than about 60 degrees, such as an angle greater than about 90 degrees or an angle greater than about 100 degrees. In some embodiments, the recess 602 may include bearing material or a bearing insert configured to reduce friction between the rod interface 302 of the shoe 202 and the recess 602. The recess 602 may be positioned closer to the piston connection point 304 than to the lower rod connection point 604. By positioning the recess 602 near the piston connection point 304, the moments and forces in the components and areas near the recess 602 and the piston connection point 304 can be made equal, thereby substantially preventing the piston head 104 (Figures 1-4) from tilting or vibrating within the cylinder 112 (Figure 1).

[0033] Non-limiting exemplary embodiments of this disclosure further include the following embodiments:

[0034] Embodiment 1: A piston assembly comprising: a piston head; an upper connecting rod rotatably coupled to the piston head; and a shoe positioned between the upper connecting rod and the inner wall of the piston head.

[0035] Embodiment 2: The piston assembly of Embodiment 1, wherein the shoe comprises a piston interface surface that is slidably in contact with the inner wall of the piston head.

[0036] Embodiment 3: A piston assembly according to Embodiment 1 or Embodiment 2, wherein the inner wall of the piston head comprises the inner wall of the piston skirt.

[0037] Embodiment 4: A piston assembly of Embodiment 3, wherein the shoe is configured to distribute lateral forces across the inner wall of the piston skirt.

[0038] Embodiment 5: A piston assembly according to any one embodiment of Embodiments 1 to 4, wherein the shoe includes a rod interface surface that is slidably in contact with the upper connecting rod.

[0039] Embodiment 6: The piston assembly of Embodiment 5, wherein the upper connecting rod has a complementary recess that slidably contacts the rod interface surface of the shoe.

[0040] Embodiment 7: A piston assembly of Embodiment 6, wherein the complementary recess has a curved surface.

[0041] Embodiment 8: A piston assembly of any one embodiment from Embodiments 1 to 7, wherein the shoe has a first width near the upper connecting rod and a second width near the inner wall of the piston head, the second width being greater than the first width.

[0042] Embodiment 9: An engine comprising: a cylinder; a crankshaft; and a piston assembly disposed within the cylinder, the piston assembly comprising: a piston head; an upper connecting rod rotatably coupled to the piston head; a lower connecting rod coupled between the upper connecting rod and the crankshaft; and a shoe slidably coupled between the upper connecting rod and the skirt of the piston head.

[0043] Embodiment 10: An engine according to Embodiment 9, wherein the shoe comprises a skirt interface surface slidably connected to the skirt of the piston head.

[0044] Embodiment 11: An engine according to Embodiment 10, wherein the skirt interface surface has a radius that substantially matches the radius of the inner surface of the piston head skirt.

[0045] Embodiment 12: An engine according to any one of Embodiments 9 to 11, wherein the upper connecting rod comprises a recess slidably coupled to a shoe.

[0046] Embodiment 13: An engine according to Embodiment 12, wherein the recess comprises a curved surface that is complementary to the rod interface surface of the shoe.

[0047] Embodiment 14: An engine according to Embodiment 12 or Embodiment 13, wherein the recess further comprises bearing material.

[0048] Embodiment 15: An engine according to any one embodiment of Embodiments 12 to 14, wherein the recess is located closer to the piston connection between the upper connecting rod and the piston head compared to the lower rod connection between the upper connecting rod and the lower connecting rod.

[0049] Embodiment 16: An upper connecting rod of a piston assembly, the upper connecting rod comprising: a piston connection point; a lower rod connection point; and a curved recess defined within the outer edge of the upper connecting rod, the curved recess being configured to receive an interface element between the upper connecting rod and the piston, and the curved recess being positioned closer to the piston connection point than to the lower rod connection point.

[0050] Embodiment 17: An upper connecting rod of Embodiment 16, wherein the piston connection point comprises a gadion pin assembly.

[0051] Embodiment 18: An upper connecting rod of Embodiment 17, wherein the lower rod connection point comprises a connector pin assembly.

[0052] Embodiment 19: An upper connecting rod according to any one embodiment of Embodiments 16 to 18, wherein the curved recess has an arc of at least 60 degrees.

[0053] Embodiment 20: An upper connecting rod according to any one embodiment of Embodiments 16 to 19, wherein the curved recess has an arc of at least 90 degrees.

[0054] Embodiments of this disclosure can substantially prevent or significantly reduce tilting or vibration of the piston head within the cylinder of an engine. By reducing or preventing tilting or vibration of the piston head, contact and associated friction between the piston head and the cylinder wall can be significantly reduced. By reducing contact between the piston head and the cylinder wall, engine efficiency can be improved and wear on the piston head and cylinder wall can be reduced. Embodiments of this disclosure described above and shown in the accompanying drawings do not limit the scope of the invention, for this reason they are merely examples of embodiments of the invention as defined by the scope of the accompanying claims and their legal equivalents. Any equivalent embodiment is intended to be within the scope of this disclosure. In practice, in addition to the embodiments shown and described herein, various modifications of this disclosure, such as useful alternative combinations of the elements described, will be apparent to those skilled in the art from this description. Such modifications and embodiments are also intended to be within the scope of the accompanying claims and their legal equivalents.

Claims

1. Piston head and, An upper connecting rod rotatably coupled to the piston head, A shoe is positioned between the upper connecting rod and the inner wall of the piston head, It comprises a recess defined on the upper connecting rod and slidably coupled to the shoe, The shoe has a first width near the upper connecting rod and a second width near the inner wall of the piston head, wherein the second width is greater than the first width. Piston assembly.

2. The piston assembly according to claim 1, wherein the shoe comprises a piston interface surface that slidably contacts the inner wall of the piston head.

3. The piston assembly according to claim 1, wherein the inner wall of the piston head is provided with the inner wall of the piston skirt.

4. The piston assembly according to claim 3, wherein the shoe is configured to distribute lateral forces across the inner wall of the piston skirt.

5. The piston assembly according to any one of claims 1 to 4, wherein the shoe includes a rod interface surface that is slidably in contact with the upper connecting rod.

6. The piston assembly according to claim 5, wherein the recess is a complementary recess that slidably contacts the rod interface surface of the shoe.

7. The piston assembly according to claim 6, wherein the complementary recess has a curved surface.

8. Cylinder and Crankshaft and A piston assembly disposed within the cylinder, wherein the piston assembly is Piston head, An upper connecting rod rotatably coupled to the piston head, The lower connecting rod is coupled between the upper connecting rod and the crankshaft, and A shoe is slidably coupled between the upper connecting rod and the skirt of the piston head. A piston assembly comprising, An engine in which the shoe has a first width near the upper connecting rod and a second width near the inner wall of the piston head, along the direction in which the rotation axis of the crankshaft extends, the second width being greater than the first width.

9. The engine according to claim 8, wherein the shoe comprises a skirt interface surface slidably connected to the skirt of the piston head.

10. The engine according to claim 9, wherein the skirt interface surface has a radius that substantially matches the radius of the inner surface of the skirt of the piston head.

11. The engine according to any one of claims 8 to 10, wherein the upper connecting rod has a recess slidably coupled to the shoe.

12. The engine according to claim 11, wherein the recess comprises a curved surface that is complementary to the rod interface surface of the shoe.

13. The engine according to claim 11, wherein the recess further comprises bearing material.

14. The engine according to claim 11, wherein the recess is located closer to the piston connection portion between the upper connecting rod and the piston head than to the lower rod connection portion between the upper connecting rod and the lower connecting rod.

15. The upper connecting rod is Piston connection point, A lower rod connection point is provided, The piston assembly according to claim 1, wherein the recess is a curved recess defined within the outer edge of the upper connecting rod, and the curved recess is positioned closer to the piston connection point than the lower rod connection point.

16. The piston assembly according to claim 15, wherein the piston connection point comprises a gadion pin assembly.

17. The piston assembly according to claim 16, wherein the lower rod connection point comprises a connector pin assembly.

18. The piston assembly according to any one of claims 15 to 17, wherein the curved recess has an arc of at least 60 degrees.

19. The piston assembly according to any one of claims 15 to 17, wherein the curved recess has at least a 90-degree arc.

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