SINGLE-ACTING HYDRAULIC CYLINDER WITH HEAD END CUSHIONING

Abstract

SINGLE-ACTING HYDRAULIC CYLINDER WITH HEAD END DAMPING This disclosure relates to a single-acting hydraulic cylinder (100) configured to provide a smooth extension stroke of a piston (102). The cylinder (100) has a piston rod (108) connected to the piston (102), in which the piston rod (108) has a plurality of ports (110) defined at predetermined positions, and the piston (102) has a groove (106) defined in fluidic communication with the ports (110) and a fluid gallery (104) defined in the piston (102). The orifices allow the fluid to flow from an annular side chamber (124) to a full bore side chamber (125) via the fluid gallery at the end of the deployment stroke, to gradually attenuate the impact of the piston (102) with a cylinder head end cover (130).The cylinder prevents jolts and jerks in a hydraulic system, providing better control and ease of operation. FIGURE 1.

Description

Title of the invention: SINGLE-ACTING HYDRAULIC CYLINDER WITH HEAD END DAMPING technical field

[0001] The embodiments of this article generally relate to hydraulic cylinders and, more particularly, to a single-acting hydraulic cylinder configured to have a soft damping effect at the end of its extension stroke. CONTEXT

[0002] A single-acting hydraulic cylinder is a type of actuator that uses hydraulic pressure to produce a force in only one direction. The single-acting hydraulic cylinder typically consists of a piston rod and optionally a piston, which are connected and housed within a cylindrical body / barrel. Hydraulic fluid enters through a single port to push the piston in one direction. The piston's return movement is usually assisted by a spring or by gravity. Single-acting hydraulic cylinders are commonly used in applications where a single, unidirectional force is required, such as in lifting mechanisms, clamping devices, and agricultural machinery.

[0003] In certain applications requiring enhanced safety measures during operation, such as when operating a lifting platform, the piston rod movement needs to be controlled to prevent sudden movement of the platform connected to the hydraulic system. To prevent sudden piston rod movement, hydraulic cylinders employ a damping effect to control the speed and force of the piston as it approaches the end of its stroke. Without damping, the piston can strike the cylinder head or base at high speed, leading to excessive noise, vibration, and potential damage to the cylinder and related components. Sudden deceleration can also cause hydraulic shock, which can compromise the integrity of the entire hydraulic system.Therefore, damping is essential to improve the durability and safety of hydraulic cylinders by reducing impact forces during the end-of-stroke phase.

[0004] Conventionally, a damping sleeve or tip is attached to the end of the piston or cylinder to achieve the damping effect in the hydraulic cylinder. When the piston is near the end of its stroke, the damping sleeve or tip gradually impedes the flow of hydraulic fluid, creating a controlled deceleration. However, the damping of The type of damped sleeve has limitations in its sizing within the narrow annular space of a cylinder. Another method involves the use of adjustable damping valves, which allow fine-tuning of the damping effect by regulating fluid flow through dedicated damping passages. However, the adjustable damping valve configuration for head-end / rod-end damping is only feasible for a double-acting hydraulic cylinder where outlet flow through a retraction port is restricted by the adjustable damping valves, and is not suitable for single-acting hydraulic cylinders. Furthermore, some cylinders incorporate a flow control port and / or valves directly within the cylinder to modulate fluid flow and provide damping.However, the combination of a check valve with orifices is adopted for this design inside the cylinder instead of a design relying solely on flow control valves.

[0005] Despite the effectiveness of the methods, there remain drawbacks associated with existing ways of achieving the damping effect in hydraulic cylinders. For example, the space required for integrating damping components can limit the compactness and versatility of the hydraulic cylinder design. This can hinder the use of damped cylinders in certain environments or lead to the need for custom designs, further increasing costs. In addition, the single orifice in the cylinder barrel for modulating fluid flow fails to provide a smooth damping effect at the end of the extension stroke. The fluid flow is suddenly reduced in the cylinder chamber, causing jerking or jolting in the piston rod when the piston is near the end of its extension stroke.

[0006] Therefore, there is a need for a single-acting hydraulic cylinder which avoids the aforementioned disadvantages. GOALS

[0007] The main object of the embodiments of the present is to provide a single-acting hydraulic cylinder which provides smooth cushioning at the end of a deployment stroke which prevents any sudden jerk in the entire hydraulic cylinder.

[0008] Another object of the embodiments of the present is to provide the single-acting hydraulic cylinder with a head end damping mechanism which improves the durability and safety of the hydraulic cylinders by reducing impact forces during the end-of-stroke phase.

[0009] Another object of the embodiments of the present is to provide the single-acting hydraulic cylinder which facilitates the flow of any fluid trapped in a chamber on the annular side to a chamber on the full bore side of a cylinder housing.

[0010] Another object of the embodiments of the present is to provide the single-acting hydraulic cylinder equipped with a damping mechanism which provides controlled operation of a hydraulic system coupled to a lifting platform which provides smooth movement of the lifting platform.

[0011] Another object of the embodiments of the present is to provide the single-acting hydraulic cylinder with the damping mechanism which attenuates the impact of the piston with a cylinder head end cover which prevents damage to components of the single-acting hydraulic cylinder, and is easy to manufacture and does not require any additional components or additional space for packaging.

[0012] These and other embodiments of this article will be better recognized and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and many specific details thereof, are given by way of illustration and not limitation. Many changes and modifications may be made within the scope of the embodiments of this article without departing from their spirit, and the embodiments of this article incorporate all such modifications. Brief description of the drawings

[0013] The embodiments are illustrated in the accompanying drawings, throughout which the same reference letters indicate corresponding parts in the various figures. The embodiments of the present instrument will be better understood from the following description with reference to the drawings, in which:

[0014] [Fig-1] represents a cross-sectional view of a single-acting hydraulic cylinder representing a piston in an initial position, according to embodiments as disclosed herein;

[0015] [Fig.2] represents a cross-sectional view of the single-acting hydraulic cylinder representing the piston in an intermediate position, according to embodiments as disclosed herein;

[0016] [Fig. 3] represents a cross-sectional view of the single-acting hydraulic cylinder representing the piston at the beginning of damping, according to embodiments as disclosed herein; and

[0017] [Fig.4] represents a cross-sectional view of the single-acting hydraulic cylinder representing the piston in a fully extended position, according to embodiments as disclosed herein. DETAILED DESCRIPTION

[0018] The embodiments of this present instrument and their various advantageous features and details are explained more fully with reference to the non-limiting embodiments illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as not to unnecessarily obscure the embodiments of this instrument. The examples used herein are intended simply to facilitate understanding of how the embodiments of this instrument can be implemented and to enable those skilled in the art to implement them. Therefore, the examples should not be interpreted as limiting the scope of the embodiments of this instrument.

[0019] The embodiments of the present achieve a single-acting hydraulic cylinder that provides smooth damping at the end of its extension stroke, thus preventing any sudden jerking in the entire hydraulic cylinder. Furthermore, the embodiments of the present achieve a single-acting hydraulic cylinder equipped with a damping mechanism that provides controlled operation of a hydraulic system coupled to a lifting platform, thereby providing smooth movement of the lifting platform. With reference to the drawings in Figures 1 to 4, where similar reference characters denote corresponding features consistently throughout the figures, the embodiments are presented.

[0020] Figures 1 and 2 show cross-sectional views of the single-acting hydraulic cylinder (100) according to the embodiments disclosed herein. The hydraulic cylinder (100) comprises a piston (102), a piston rod (108) connected to the piston (102), and a cylinder head end cover (130) housed in a cylinder housing (122) of the single-acting hydraulic cylinder (100). The piston (102) is designed to be hydraulically actuated to move the piston (102) from an initial position (PI) (as shown in [Fig. 1]) to a deployed position (P2) (as shown in [Fig. 4]). In the initial position (PI), the piston (102) is designed to be in contact with a cylinder cap end cover (140) of the single-acting hydraulic cylinder (100), and in the deployed position (P2) the piston (102) is designed to be in contact with the cylinder head end cover (130) of the single-acting hydraulic cylinder (100).In one embodiment, the piston (102) is designed to return to the initial position (PI) from the deployed position (P2) with oil released from the cylinder into a reservoir and is assisted by gravity. The piston rod (108) is connected to the piston (102) such that when the piston (102) is moved from the initial position (PI) to the deployed position (P2), the piston rod (108) is designed to extend outwards from the cylinder housing (122). single-acting hydraulic cylinder (100). When the piston (102) returns to its initial position (PI) from the extended position (P2), the piston rod (108) retracts into the cylinder housing (122) of the single-acting hydraulic cylinder (100). The cylinder head end cover (130) is disposed / defined within the cylinder housing (122) of the single-acting hydraulic cylinder (100) and is designed to receive the piston rod (108) when the piston (102) is moved from the initial position (PI) to the extended position (P2). In one embodiment, the cylinder head end cover (130) is designed to accommodate a damping seal (132) (as shown in Figures 1 to 4).The damping seal (132) is designed to receive the piston rod (108) through it when the piston (102) is moved from the initial position (PI) to the deployed position (P2) to reduce the speed of the piston (102) near the cylinder head end cover (130) by covering orifices (110) (as shown in [Fig.1]) provided on the piston rod (108) which dampens the movement of the piston rod (108). In addition, the single-acting hydraulic cylinder (100) has an inlet port (not shown) to allow fluid to flow into the cylinder housing (122) of the single-acting hydraulic cylinder (100), and a piston seal (126) (as shown in Figures 1, 2 and 4) provided on the piston (102) to prevent fluid flow at a base (102B) (as shown in [Fig.2]) of the piston (102).Fluid entering the cylinder housing (122) of the single-acting hydraulic cylinder (100) accumulates near the base (102B) of the piston (102) and exerts pressure on the base (102B) of the piston (102), which pushes the piston (102) from the cylinder cap end cover (140) towards the cylinder head end cover (130) within the cylinder housing (122) of the single-acting hydraulic cylinder (100). Although the piston seal (126) impedes fluid flow at the base (102B) of the piston (102), some fluid flows into an annular-side chamber (124) (as shown in Figures 1 to 3) of the cylinder housing (122). The annular-side chamber (124) is defined between the piston (102) and the cylinder head end cover (130). When the piston (102) approaches the cylinder head end cover (130) (as shown in [Fig.2]), the damping seal (132) provided in the end cover of the cylinder head (130) reduces the speed of the piston (102) by covering orifices (110) (as shown in [Fig. 1]) provided on the piston rod (108), thereby dampening the displacement of the piston rod (108). This reduction in the speed of the piston (102) results in an accumulation of fluid in the annular-side chamber (124) as the piston (102) moves towards the deployed position (P2).

[0021] Figures 3 and 4 show cross-sectional views of the single-acting hydraulic cylinder (100) according to the embodiments disclosed herein. In one embodiment, the piston (102) has a defined fluid gallery (104). in the piston (102), and a groove (106) defined in fluidic communication with the fluid gallery (104). The fluid gallery (104) extends between the base (102B) of the piston (102) and the groove (106). The fluid gallery (104) is designed to direct the fluid entering through the groove (106) of the piston (102) so that it flows to a full-bore-side chamber (125) (as shown in [Fig. 2]) adjacent to the cylinder cap end cover (140). The full-bore-side chamber (125) of the cylinder housing (122) is defined between the base (102B) of the piston (102) and the cylinder cap end cover (140). In one embodiment, the piston rod (108) has a plurality of orifices (110) defined at predetermined positions therein. The groove (106) of the piston (102) is in fluidic communication with the orifices (110).The plurality of orifices (110) are designed to allow the fluid accumulated in the annular side chamber (124) to flow into the fluid gallery (104) through the groove (106) and the fluid from the fluid gallery (104) flows to the full bore side chamber (125) of the cylinder housing (122) for the reduction of a speed of movement of the piston (102) towards the cylinder head end cover (130) which attenuates the impact of the piston (102) with the cylinder head end cover (130) at the end of a deployment stroke in which the piston (102) is moved to the deployed position (P2).Furthermore, each of the ports (110) is set at a corresponding predetermined position in the piston rod (108) so that each of the ports (110) is sequentially covered by the damping seal (132) in the cylinder head end cover (130) of the cylinder (100) (shown in Figures 2, 3, and 4). This gradually closes the fluid flow from the annular-side chamber (124) to the full-bore-side chamber (125) through the ports (110) as the piston (102) is moved to the deployed position (P2). This sequential closure of the ports (110) ensures that the fluid flow cross-section exiting the annular-side chamber (124) is gradually reduced, preventing a sudden decrease in fluid flow rate and thus providing a smooth deployment stroke.In one embodiment, the plurality of ports (110) (as shown in Figures 1 and 2) comprises at least one first port (112), at least two second ports (114), and at least one third port (116) (as shown in Figures 2 to 4). The at least one first port (112) is defined in the piston rod (108) near the base (102B) of the piston (102). For the purposes of this description and to facilitate understanding, the first port (112) is considered to be an angular port defined in the piston rod (108) at a predetermined angle with respect to an axis of the piston rod (108). The predefined angle of the first orifice (112) is 40 degrees relative to the axis of the piston rod (108), which provides an inclined flow path for the fluid to flow from the annular side chamber (124) into. The groove (106) allows the fluid to flow into the fluid gallery (104). In one embodiment, the first orifice (112) has a diameter of 0.8 + / - 0.1 mm. The first orifice (112) provides an inclined flow path for the fluid to flow from the annular-side chamber (124) into the groove (106) defined in the piston (102). The inclined flow path ensures that any fluid trapped near the cylinder head end cap (130) in the annular-side chamber (124) is returned through the fluid gallery (104) to the piston (102) (shown in [Fig. 4]). Furthermore, at least two second ports (114) are defined in the piston rod (108) perpendicular to the axis of the piston rod (108) and are arranged in a linear or angular pattern with respect to at least one first port (112). In one embodiment, the piston rod (108) has four second ports (114).Each second orifice (114) has a diameter of 0.38 + / - 0.05 mm. Furthermore, at least one third orifice (116) is defined on the piston rod (108) perpendicular to the axis of the piston rod (108) and is positioned following the linear or angular array of at least two second orifices (114). In one embodiment, the second and third orifices (114, 116) are aligned with each other. In another embodiment, the second and third orifices (114, 116) are positioned in different orientations on the piston rod (108) in a parallel plane. For example, the second and third orifices (114, 116) are radially positioned on the piston rod (108) in the parallel plane. In one embodiment, the third orifice (116) has a diameter of 2.5 + / - 0.1 mm.At least one third orifice (116) is designed to be covered by the damping seal (132) in the cylinder head end cover (130) (as shown in [Fig. 2]), and subsequently the second orifices (114) (as shown in [Fig. 3]) and the first orifice (112) (as shown in [Fig. 4]) are designed to be covered by the damping seal (132) and the cylinder head end cover (130) sequentially, which reduces the speed of the piston (102) moving towards the cylinder head end cover (130) when the piston (102) is moved from the initial position (PI) to the deployed position (P2). The piston rod (108) has a tapered portion (115) (as shown in [Fig. 3]).3]) designed to facilitate fluid flow from the annular-side chamber (124) to the first orifice (112) at the end of the deployment stroke, wherein the tapered portion (115) is adjacent to the base (102B) of the piston (102) and accommodates an inlet of the first orifice (112). In one embodiment, the damping seal (132) is designed to cover the orifices (110) to block fluid flow into the orifices (110), thereby reducing the velocity of the piston (102) near the cylinder head end cover (130) when a section of the piston rod (108) having the plurality of orifices (110) is. received by the cylinder head end cover (130) during a movement of the piston (102) from the initial position (PI) to the deployed position (P2).

[0022] Furthermore, in one embodiment, the single-acting hydraulic cylinder (100) includes a check valve (128) (as shown in Figures 1, 3 and 4) disposed within the piston (102). The check valve (128) is configured to allow fluid to flow from the full-bore side chamber (125) to the annular side chamber (124) of the single-acting hydraulic cylinder (100) when the piston (102) is moved from the deployed position (P2) to the initial position (PI) during a retraction stroke to fill the annular side chamber (124) before the orifices (110) fully open into the annular side chamber (124) for smooth retraction. The check valve (128) obstructs the flow path so that the fluid in the annular side chamber (124) flows back towards the full bore side chamber (125) during a smooth damping at the end of the deployment stroke.In one embodiment, the non-return valve (128) is provided in fluidic communication with the annular side chamber (124) through a second fluid gallery (128G) (as shown in Figures 1, 3 and 4) defined in the piston (102).

[0023] The technical advantages of the single-acting hydraulic cylinder (100) are as follows. The single-acting hydraulic cylinder (100) is equipped with a damping mechanism that improves the durability and safety of the hydraulic cylinders by reducing impact forces during the end-of-stroke phase. The single-acting hydraulic cylinder (100) with the damping mechanism provides controlled operation of a hydraulic system coupled to a lifting platform, resulting in smooth movement of the lifting platform. The single-acting hydraulic cylinder (100) dampens the impact of the piston with a cylinder head end cover by means of damping, which prevents damage to components of the single-acting hydraulic cylinder.A smooth and controlled piston deployment stroke provides enhanced safety by preventing any sudden jerking or abrupt movement in the hydraulic system, and is easy to manufacture and requires no additional components or space for packaging.

[0024] The preceding description of specific embodiments will thus fully reveal the general nature of the embodiments herein, which others may, by the application of current knowledge, readily modify and / or adapt for various applications such as specific embodiments without departing from the generic concept, and, consequently, such adaptations and modifications should and are intended to be encompassed within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the phraseology or terminology employed herein is for descriptive purposes and not for limitation. Therefore, although the embodiments Although the present document has been described in terms of embodiments, a person skilled in the art will recognize that the embodiments of this document can be put into practice with modifications within the spirit and scope of the embodiments as described herein.

Claims

Demands

1. Single-acting hydraulic cylinder (100) comprising: a piston (102) designed to be hydraulically actuated for the movement of said piston (102) from an initial position (PI) to a deployed position (P2); and a piston rod (108) connected to said piston (102), in which said piston rod (108) has a plurality of orifices (110) defined at predetermined positions therein, in which said piston (102) has a groove (106) formed in fluidic communication with said plurality of orifices (110) of said piston rod (108) and a fluid gallery (104) defined in said piston (102);and said plurality of orifices (110) are designed to allow fluid accumulated in an annular-side chamber (124) of a cylinder housing (122) to flow into said fluid gallery (104) through said groove (106), and the fluid from the fluid gallery (104) flows to a full-bore-side chamber (125) of said cylinder housing (122), and each of said orifices (110) is covered sequentially by a damping seal (132) provided in a cylinder head end cover (130) of said hydraulic cylinder (100) to block fluid flow from said annular-side chamber (124) to said orifices (110) for reducing the speed of movement of said piston (102) towards said cylinder head end cover (130), thereby attenuating the impact of said piston (102) with said cylinder head end cover (130) at the end of a deployment stroke in which said piston (102) is moved to said deployed position (P2).;

2. Single-acting hydraulic cylinder (100) according to claim 1, wherein each of said orifices (110) are covered sequentially by said damping seal (132) provided in said cylinder head end cover (130) which gradually closes a fluid flow from said annular side chamber (124) to said full bore side chamber (125) through said orifices (110) when said piston (102) is moved to the deployed position (P2).

3. Single-acting hydraulic cylinder (100) according to claim 1, wherein said plurality of orifices (110) comprises: at least one first orifice (112) defined in said piston rod (108); at least two second orifices (114) defined in said piston rod (108) perpendicular to an axis of said piston rod (108) and which are arranged in a linear or angular network with respect to said at least one first orifice (112);and at least one third orifice (116) defined in said piston rod (108) perpendicular to said axis of said piston rod (108) and which is positioned following said second orifices (114), in which said at least one third orifice (116) is designed to be covered by said damping seal (132) accommodated in said cylinder head end cover (130), and subsequently said second orifices (114) and said first orifice (112) are designed to be covered by said damping seal (132) in said cylinder head end cover (130) in a sequential manner which reduces the speed of movement of said piston (102) towards said cylinder head end cover (130) when said piston (102) is moved from said initial position (PI) to said deployed position (P2).

4. Single-acting hydraulic cylinder (100) according to claim 3, wherein said first orifice (112) is an angular orifice which is defined in said piston rod (108) at a predetermined angle with respect to said axis of said piston rod (108); said first orifice (112) is located adjacent to a base (102B) of said piston (102); each of said second and third orifices (114, 116) are aligned with each other or positioned in different orientations on said piston rod (108) in a parallel plane; and said first orifice (112) has a diameter of 0.8 + / - 0.1 mm, wherein the predefined angle of said first orifice (112) is 40 degrees with respect to said axis of said piston rod (108) which provides an inclined flow path for the fluid to flow from said annular side chamber (124) into said groove (106).

5. Single-acting hydraulic cylinder (100) according to claim 3, the plurality of second ports (114) comprises four second ports (114), in which each of said second ports (114) has a diameter of 0.38 + / - 0.05 mm; and said third port (116) has a diameter of 2.5 + / - 0.1 mm.

6. Single-acting hydraulic cylinder (100) according to claim 4, wherein said piston rod (108) has a tapered portion (115) designed to facilitate fluid flow from said annular side chamber (124) to said first orifice (112) at the end of the deployment stroke, wherein said tapered portion (115) is defined on said piston rod (108) and is positioned adjacent to said base (102B) of said piston (102) and accommodates an inlet of the first orifice (112).

7. Single-acting hydraulic cylinder (100) according to claim 1, wherein said single-acting hydraulic cylinder (100) comprises a check valve (128) disposed within said piston (102), wherein said check valve (128) is configured to impede the flow of fluid from said annular side chamber (124) to said full bore side chamber (125) adjacent to a cylinder cap end cover (140) of said cylinder (100) during soft damping at the end of the deployment stroke;and said check valve (128) is configured to permit fluid to flow from said full bore side chamber (125) to said annular side chamber (124) of said single-acting hydraulic cylinder (100) when said piston (102) is moved from the deployed position (P2) to the initial position (PI) during a retraction stroke to fill said annular side chamber (124) before said orifices (110) fully open into said annular side chamber (124) for smooth retraction.;

8. Single-acting hydraulic cylinder (100) according to claim 7, wherein said check valve (128) is provided in fluidic communication with said annular side chamber (124) through a second fluid gallery (128G) defined in said piston (102).

9. Single-acting hydraulic cylinder (100) according to claim 1, wherein the sequential closure of said orifices (110) by said damping seal (132) ensures that the cross-sectional fluid flow at the outlet of said chamber on the annular side (124) is gradually decreased, which in turn prevents a sudden decrease in fluid flow rate, thus providing a smooth deployment stroke; and said piston (102) is designed to return to the initial position (PI) from the deployed position (P2) under the effect of gravity with a release of oil from the cylinder to a reservoir and is aided by gravity.

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