Cylinder guard assembly

Abstract

A cylinder guard assembly 40 for mounting to a cylinder 11 comprises a guard eye mount 44 for mounting the cylinder guard 41 to the rod eye 14 and a retention assembly for attaching the cylinder to th

Description

Technical Field The present disclosure relates to a cylinder guard assembly for mounting to a cylinder and a cylinder assembly comprising the cylinder guard assembly and cylinder. The cylinder may be a hydraulic or pneumatic cylinder. Background Work machines, or vehicles such as excavators or backhoe loaders, typically function and perform work through the extension and retraction of hydraulic cylinders. These hydraulic cylinders are attached either side of a pivot to allow the relative rotation of components of the work machine, such as a boom arm, stick, and / or bucket. Hydraulic cylinders comprise a piston, comprising a piston head and a rod eye mounted at opposing ends of a piston or cylinder rod, mounted inside a cylinder barrel. The piston moves in response to work machine fluid (which could be hydraulic fluid / hydraulic oil) being pumped into the barrel on either side of the piston head. In some applications, hydraulic cylinders require additional guarding of the cylinder rod area to help protect the cylinder from the environment. If a cylinder rod does not have guarding, then the rod can be scratched or bent by external objects, thereby leading to leaks between the rod and barrel. Designing a retention system for a guard can be a challenge as the guard needs to be easy to remove for cylinder service, have a low profile and be robust enough to be able to withstand and not snag on external objects or other parts of the work machine. US10392783B2 and discloses a protective cover having one side supported by a cover guide provided on the barrel, while the other side is mounted on a rod eye. A protective protrusion is provided protruding outward in a radial direction of the rod eye. The protective cover is formed having a plate shape by a material having elasticity, and the protective cover includes a plate part for protecting the rod between the cover guide and the rod eye and a winding part formed so as to be wound around an outer periphery of the rod eye from a distal end side of the plate part. JP5526106B2 discloses a similar configuration of a cylinder guard, in which the cover includes a protrusion which surrounds a protruding mount part on the rod eye. However, the protrusions of US10392783B2 and JP5526106B2 are disadvantageous because they can block the removal of the cover when slid on or off the cylinder along the axis of extension. Furthermore, the protrusions are exposed and can be liable to shearing under impact. This is particularly problematic in applications in which the guard is removed, since without the guard in place the protrusions become more exposed to damaging impacts and are liable to snagging on other parts of the work machine. Summary An object of the present disclosure is to provide an improved cylinder guard assembly. A further object is to provide a retention system for a sliding cylinder guard that allows for easy installation and removal, whilst still being robust and low profile. The present disclosure therefore provides a cylinder guard assembly for mounting to a cylinder, a cylinder assembly comprising the cylinder guard assembly and cylinder and a method of assembly thereof in accordance with the claims. The cylinder comprises a piston rod extending from a barrel to a rod eye. The cylinder guard assembly comprises a cylinder guard and a retention system. The cylinder guard comprises a guard eye mount for mounting the cylinder guard to the rod eye in a mounted configuration. The guard eye mount comprises a guard aperture therethrough. The retention system comprises a spacer and a fastener. The spacer may comprise a spacer body and a spacer aperture through the spacer body. The spacer may be configured to extend through the guard aperture to the rod eye in the mounted configuration. The fastener is configured to, in the mounted configuration, fasten the cylinder guard and spacer to the rod eye and may extend through the spacer aperture to perform such fastening. The cylinder guard and retention system may be configured such that, in the mounted configuration, the cylinder guard can move relative to the rod eye within a float range. In the cylinder assembly, the cylinder guard assembly is mounted to the cylinder in the mounted configuration. Therefore, the spacer extends through the guard aperture to the rod eye and the fastener may extend through the spacer aperture to fasten the cylinder guard and spacer to the rod eye. The cylinder guard may protect and cover or overlie the length of the piston rod and at least part of the barrel when the cylinder is in both its fully retracted and fully extend configurations. The spacer and / or guard aperture configuration allows the cylinder guard to float when mounted to the cylinder, which reduces the effect of misalignments and vibrations, whilst still providing a low profile cylinder guard. The float enables the cylinder guard to move slightly under load or impact relative to the rod eye, thereby significantly reducing the risk of sheering of the fastener and thus separation of the cylinder guard from the cylinder. The spacer also allows for the fastener to be sufficiently preloaded, whilst allowing such float At the same time, however, under a substantial impact the cylinder guard can still break away from the cylinder, such as at the fastener. The force of impact at which breakaway occurs can be controlled by selection of a suitable fastener. The float range may be dependent upon the size and / or materials of the spacer and / or the size of the guard aperture. In particular, if the guard aperture has a greater diameter than the outer diameter of the spacer, the float range is increased. If the spacer comprises a deformable material such as rubber, the float range may also be increased. The rod eye may comprise a spacer counterbore extending into the rod eye and the spacer may be located in the spacer counterbore. The spacer counterbore allows for the spacer to be able to carry part of the shear load generated by the cylinder guard, thereby allowing for a smaller fastener to be used. The cylinder guard assembly therefore protects the piston rod from scratches and other impacts, maintaining the seal between the piston rod and barrel. The cylinder guard assembly of the present disclosure is more compact than that of the prior art discussed above. Furthermore, by avoiding the need for protrusions on the rod eye, snagging and damage to the rod eye can be avoided or reduced when the cylinder guard is not mounted in place. In addition, the absence of protrusions makes it much easier to slide the cylinder guard onto the cylinder from the rod eye end of the cylinder. The method comprises mounting the cylinder guard assembly to the cylinder. The guard eye mount is mounted to the rod eye. The retention system of the cylinder guard assembly is mounted to the cylinder guard and cylinder. The spacer is inserted to extend through the guard eye mount to the rod eye, and the fastener is inserted through the spacer aperture to fasten the cylinder guard and spacer to the rod eye. The method may further comprise selecting the spacer from a plurality of spacers, the plurality of spacers comprising different dimensions and / or material(s) for providing different float of the cylinder guard relative to the cylinder. In this manner, an operator can select a spacer with a suitable float for their application. The present disclosure may further provide a work machine comprising the cylinder assembly. The cylinder may be mounted between movable parts, such as an arm arrangement or tool, of a work machine and may be for moving the movable parts relative to one another. Brief Description of the Drawings By way of example only, embodiments according to the present disclosure are now described with reference to, and as shown in, the accompanying drawings, in which: FIGURE 1 is a perspective view of an embodiment of a cylinder assembly of the present disclosure, comprising a cylinder guard assembly mounted to a cylinder, in which a retention system of the cylinder guard assembly is shown in an exploded configuration and the cylinder is shown in an extended configuration; FIGURE 2 is a perspective view of the cylinder of Figure 1 in the extended configuration and without the cylinder guard assembly mounted thereto; FIGURE 3 is a magnified view showing a rod eye of a piston rod of the cylinder of Figure 1; FIGURE 4 is a side view of the cylinder assembly of Figure 1 with the cylinder in a retracted configuration; FIGURE 5 is a cross-sectional view of the rod eye of the cylinder assembly of Figure 1 showing the cylinder guard assembly mounted to the rod eye by the retention system; FIGURE 6 is a perspective view of a spacer of the cylinder guard assembly of Figure 1 FIGURE 7 is a perspective view showing a further embodiment of the spacer in an assembled configuration with a fastener; FIGURE 8 is a perspective view of the fastener and spacer of Figure 7 in an exploded view; and FIGURE 9 is a perspective view of the cylinder assembly of Figure 1 showing the float range of the cylinder guard relative to the rod eye whilst being fastened thereto. Detailed Description The ensuing description provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the invention. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements, including combinations of features from different embodiments, without departing from the scope of the invention. Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that embodiments may be practised without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and / or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and / or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. The present disclosure generally relates to a cylinder guard assembly that allows for a cylinder guard to easily be installed onto a cylinder. The cylinder guard is sandwiched between the rod eye and a spacer, both being retained with a single bolt or fastener. The cylinder rod eye may comprise a tapped hole for receiving the fastener and may comprise a counterbored hole for receiving the spacer. An isolating material such as a washer or O-ring may be placed between the guard and spacer to help cushion vibrations. Figure 1 illustrates a cylinder assembly 10 in accordance with the present disclosure, comprising a cylinder 11 (shown in further detail in Figures 2 and 3) and a cylinder guard assembly 40 (shown in further detail in Figures 4 and 5) mounted to the cylinder 11. The cylinder 11 comprises a barrel 12 and a piston rod 13 slidably mounted in the barrel 12. The piston rod 13 is configurable between an extended configuration (Figures 1 and 2) and a retracted configuration (Figure 4). The piston rod 13 may comprise a piston head (not shown) within the barrel 12 and, as is known in the art, a hydraulic or pneumatic system (not shown) may be controlled to supply hydraulic or pneumatic fluid to either side of the piston head so as to move the piston rod 13 between the extended and retracted configurations. The piston rod 13 comprises a rod eye 14 at an opposing end thereof to the barrel 12. The rod eye 14 is for mounting the piston rod 13 and cylinder 11 to a part of a work machine. The rod eye 14 may comprise a rod eye aperture 15 for receiving a rod eye bearing 16 and for mounting to a part of a work machine. The barrel 12 may also comprise a barrel eye 17, at an opposing end thereof to the piston rod 13, for mounting the barrel 12 and cylinder 11 to a part of a work machine. The barrel eye 17 may comprise a barrel eye aperture 18 for receiving a barrel eye bearing 19 and for mounting to a part of the work machine. The cylinder 11 may thus be mountable, by the rod eye 14 and / or barrel eye 17, between movable parts of a work machine for moving those parts. For example, the cylinder is mountable to an arm arrangement (such as comprising a stick or boom) or tool of the work machine. In a particular embodiment in which the work machine comprises an excavator or other machine with an arm arrangement (such as a backhoe loader), the cylinder 11 may be mountable between moving parts of a tool (such as for opening and closing the lid of a bucket), for moving a tool relative to a stick, for moving a boom relative to a stick and for moving a boom relative to a main body of the work machine. The rod eye 14 may comprise a rod eye body 20 and the rod eye aperture 15 may extend through the rod eye body 20 such that the rod eye bearing 16 is mountable in the rod eye body 20. The rod eye body 20 may thus be substantially tubular in shape and may comprise a rod eye outer surface 21 extending parallel to and radially around a central axis 22 of the rod eye aperture 15. The rod eye outer surface 21 may comprise a flat portion 23 from which the piston rod 13 extends and a curved portion 24 extending from the flat portion 23 around the rod eye body 20 on an opposing side thereof to the cylinder guard assembly 40. The flat portion 23 may be orthogonal to the direction of extension and retraction of the piston rod 13 with respect to the barrel 12. The rod eye 14 may further comprise an eye mount surface 25 for receiving the cylinder guard assembly 40 thereon. The eye mount surface 25 may be planar or flat for receiving the cylinder guard assembly 40 in a well-supported manner with substantial contact therewith. The eye mount surface 25 may be part of the rod eye outer surface 21 and may extend between the curved portion 24 and the flat portion 23 thereof. The eye mount surface 25 may extend from a rod eye inner edge 30, the rod eye inner edge 30 being at the closest part of the rod eye 14 to the barrel 12, and along the rod eye body 20 to at least the rod eye aperture central axis 22. The rod eye 14 may comprise the flat portion 23 extending perpendicularly from the eye mount surface 25 at the rod eye inner edge 30 as illustrated. The eye mount surface 25 may extend parallel to the direction of extension and retraction of the piston rod 13 with respect to the barrel 12 and may extend parallel to the rod eye aperture central axis 22. The rod eye 14 may comprise a spacer counterbore 26 extending into the rod eye 14, such as into the rod eye body 20. The spacer counterbore 26 may extend into the rod eye 14 from the eye mount surface 25 as illustrated. The rod eye 14 may further comprise a fastener bore 27, or tapped hole, extending into the rod eye 14 from the spacer counterbore 26. The diameter of the fastener bore 27 is less than the diameter of the spacer counterbore 26. As a result, the spacer counterbore 26 forms a spacer mounting surface 28 extending around the fastener bore 27. The counterbore(s) 26, 27 may be located substantially centrally along the rod eye aperture central axis 22 and substantially halfway across the width of the rod eye 14, the width being the direction perpendicular to the direction of extension and retraction of the piston rod 13 with respect to the barrel 12. The rod eye 14 may further comprise a grease port 29 extending from the rod eye outer surface 21, such as from the curved portion 24, into the rod eye body 20. The grease port 29 may extend through the rod eye body 20 to the rod eye aperture 15 and may be for supplying grease or lubricant to the rod eye bearing 16. The cylinder guard assembly 40 is configured to be mounted to the cylinder 11 for providing protection thereto. The cylinder guard assembly 40 is, in particular, configured to be mounted to the piston rod 13 such that the assembly 40 moves with the piston rod 13 between its extended and retracted positions. In particular, the cylinder guard assembly 40 may protect at least part or all of the piston rod 13 from external impact and therefore extends from the rod eye 14 to at least the barrel 12 when the cylinder 11 is in the extended configuration. In the retracted configuration, the cylinder guard assembly 40 extends along a substantial portion of the length (i.e. the direction of the extension / retraction of the piston rod 13) of the barrel 12. The cylinder guard assembly 40 comprises a cylinder guard 41 for protecting the piston rod 13 and / or barrel 12 and a retention system 42 for securing the cylinder guard 41 to the piston rod 13 in a mounted configuration (shown in Figures 4 and 5). The cylinder guard 41 comprises a guard eye mount 44 for mounting the cylinder guard 41 to the rod eye 14 in the mounted configuration and may comprise a shroud 50 for at least partially covering the piston rod 13 and / or barrel 12. The shroud 50 may extend from the guard eye mount 44. The internal diameter of the shroud 50 may be at least, or at least 105% or 110% of, the external diameter of the barrel 12 such that the shroud 50 can extend around and at least partially cover the barrel 12. The shroud 50 may be configured to extend along at least part of the piston rod 13, for example along at least 75% of the length of the piston rod 13 when in the extended configuration. The shroud 50 may be configured to extend along the piston rod 13 and at least partially overlap the barrel 12 in the extended configuration, as illustrated in Figure 1. In the retracted configuration, the shroud 50 may extend along at least 50%, or at least 75% of the length of the barrel 12, as illustrated in Figure 4. The shroud 50 may be substantially tubular and extend around at least part of the circumference of the piston rod 13 and / or barrel 12. In particular, the shroud 50 may extend around at least 50% or 75% of the circumference of the piston rod 13 along at least 50% of the length of the piston rod 13 when in the extended or retracted configurations. Hence the shroud 50 may comprise a slot 51 along its length (i.e. along the length of the tube such that the tube is open along its length through the slot) and the piston rod 13 may be accessible through the slot 51. The slot 51 may enable the shroud 50 to be mounted onto the piston rod 13, by inserting the piston rod 13 through the slot 51. The cylinder guard 41 may comprise a guard barrel mount 55 at an opposing end of the shroud 50 to the guard eye mount 44 such that shroud 50 extends from the guard eye mount 44 to a guard barrel mount 55. The cylinder guard 41 is mounted to the barrel 12 via the guard barrel mount 55 such that the guard barrel mount 55 provides radial support to the cylinder guard 41 (i.e. support extending radially outwards from the direction of extension / retraction of the piston rod 13). In particular, the guard barrel mount 55 may be slidably mounted to the barrel 12 in the mounted configuration such that the guard barrel mount 55 can slide along the barrel 12 as the piston rod 13 extends and retracts from the barrel 12. The guard barrel mount 55 may comprise at least one low friction contact pad 56 for contacting and sliding along the outer surface of the barrel 12. The guard barrel mount 55 may comprise a plurality of contact pads 56, such as three, spaced around the circumference of the end of the shroud 50. The guard eye mount 44 comprises a guard aperture 57 extending therethrough. The guard eye mount 44 may be configured to be mounted flush with the eye mount surface 25 in the mounted configuration. In particular, the guard eye mount 44 may comprise a plate with a lower guard eye mount surface 58 for mounting to the eye mount surface 25 and the lower guard eye mount surface 58 may be planar to match the planar eye mount surface 25. As a result, contact therebetween is increased, providing improved support for the cylinder guard 41 on the rod eye 14. A low profile can also be achieved by virtue of the guard eye mount 44 comprising a plate, thereby reducing the chances of snagging or impacts therewith. The guard eye mount 44 may comprise an upper guard eye mount surface 59, which may also be planar and thus have a low profile. The cylinder guard 41 may be formed of a sufficiently resilient material to absorb impacts thereon and protect the cylinder 11. Suitable materials include metal, such as steel, stainless steel, aluminium, titanium, or non-metallic materials such as plastic, fiberglass, or carbon fibre. The retention system 42 is best illustrated in Figures 1,5 and 6 and generally comprises a spacer 60 for mounting to the cylinder guard 41 and a fastener 70 for extending through the spacer 60 to hold the cylinder guard 41 and retention system 42 in the mounted configuration (see Figures 4 and 5). The retention system 42 may further comprise an isolator 80 configured to be located between the spacer 60 and the cylinder guard 41. The spacer 60 is best illustrated in Figures 1,5 and 6. In the illustrated embodiment, the spacer 60 comprises a spacer body 61 and a spacer aperture 62 through the spacer body 61. The spacer aperture 62 is able to receive the fastener 70 therethrough and is a through hole extending entirely through the spacer 60. The spacer 60 may comprise a spacer axis - IQ- 65 extending through the centre of the spacer aperture 62. In the mounted configuration, the fastener 70 extends along the spacer axis 65. The spacer body 61 is configured to extend through the guard aperture 57 to the rod eye 14 in the mounted configuration. The guard aperture 57 and spacer counterbore 26 may be aligned with one another in the mounted configuration and may have substantially the same diameter such that the spacer 60 can fit through them both. The spacer body 61 may fit in the guard aperture 57, extend at least partially into the rod eye 14 and / or extend at least partially over the upper guard eye mount surface 59. In particular, the spacer 60 may be configured to, in the mounted configuration, extend through the guard aperture 57 into the spacer counterbore 26. The spacer axis 65 may be coaxial with the central axis of extension of the spacer counterbore 26. As best illustrated in Figure 6, the spacer body 61 may comprise a first spacer portion 63 extending from a second spacer portion 64 along the spacer axis 65. In the mounted configuration, the second spacer portion 64 may be configured to be mounted in the guard aperture 57 and mounted in the rod eye 14, particularly in the spacer counterbore 26. Thus, the spacer counterbore 26 and second spacer portion 64 may have substantially the same outer diameters. The first spacer portion 63 may have a greater outer diameter (the dimension extending radially outwardly and perpendicular from the spacer axis 65) than the second spacer portion 64. The first spacer portion 63 may be configured to be mounted on the opposing side of the guard eye mount 44 to the rod eye 14 in the mounted configuration and may thus extend partially across the upper guard eye mount surface 59, between the upper guard eye mount surface 59 and the fastener 70. The spacer 60 and spacer body 61 may be generally tubular as illustrated and may be rotationally symmetric around the spacer axis 65. The spacer body 61 extends along a length along the spacer axis 65 and the length of the first spacer portion 63 may be less than the length of the second spacer portion 64 (in other words, the second spacer portion 64 extends along the spacer axis 65 by a greater distance than the first spacer portion 63). Therefore, the first spacer portion 63 may be substantially disc shaped with a circular outer circumference extending radially around the spacer axis 65. The second spacer portion 64 may substantially be a hollow cylinder, with a circular outer circumference extending radially around the spacer axis 65. The spacer 60 of Figures 1,4, 5 and 6 comprises a unitary spacer body 61, with the first and second spacer portions 63, 64 joined together as one part. However, as shown in Figures 7 and 8, the spacer 60 and spacer body 61 may be non-unitary and the first and second spacer portions 63, 64 may be separate parts. In particular, the first spacer portion 63 may be a washer or the like and the second spacer portion 64 may be a tubular spacer. Other than being in separate parts, the above description of the spacer 60 in Figures 1,4, 5 and 6 equally applies to the spacer 60 of Figures 7 and 8 and thus the same reference numerals have been shown in Figures 7 and 8 as in the earlier figures. By virtue of the material and / or size of the spacer 60, as discussed in further detail below, in the mounted configuration the cylinder guard 41 can move relative to the rod eye 14 by virtue of the arrangement of spacer 60. The spacer 60 may comprise a rigid material such as a metal, or a resiliently deformable material such as plastic or rubber. The fastener 70 extends through the spacer aperture 62 to fasten the cylinder guard 41 and spacer 60, and isolator 80 if present, to the rod eye 14 in the mounted configuration. The fastener 70 may extend along a fastener axis 75 and, in the mounted configuration, may extend from the opposing side of the spacer 60 to the guard eye mount 44, through the spacer aperture 62 and into the fastener bore 27. The fastener axis 75 is coaxial with the spacer axis 65 in the mounted configuration. The fastener 70 may comprise a bolt configured to extend through the spacer 60 for engagement with a thread of the rod eye 14, which may be in the fastener bore 27 (for example when it comprises a tapped hole). The bolt may comprise a bolt head 71 and a shaft 72 extending from the bolt head 71. In the mounted configuration, the shaft 72 may be mounted in the spacer aperture 62 and fastener bore 27 and the first spacer portion 63 (and isolator 80 if present) may be located between the guard eye mount 44 and bolt head 71. The isolator 80 is configured to be mounted between the spacer 60, particularly the first spacer portion 63, and the guard eye mount 44. The isolator 80 may therefore provide some cushioning of vibrations between the spacer 60 and the cylinder guard 41. The isolator 80 may comprise a resiliently deformable material, such as rubber, having some flexibility and elasticity. The isolator 80 may comprise a washer or O-ring. Industrial Applicability The cylinder guard assembly 40, including the cylinder guard 41 and retention system 42, is separable from the cylinder 11 by an operator of the work machine on which the cylinder 11 is mounted and may be supplied separately, such as an optional extra, to the cylinder 11. Therefore, in instances where protection of the cylinder 11 is not required, the cylinder guard assembly 40 need not be mounted to the cylinder 11. However, in certain applications protection of the cylinder 11 may be necessary, for example if the work machine will be operated near multiple objects that might impact the cylinder 11, if there is a risk of debris impacting the cylinder 11 or if the setup of the work machine is such that items, such as electric or hydraulic cables, might snag on the cylinder 11. The operator can then mount the cylinder guard assembly 40 to the cylinder 11 in the mounted configuration for protection. To assemble the parts in the mounted configuration, initially the cylinder guard 41 may be mounted to the cylinder 11. The shroud 50 may be slid over the piston rod 13 by feeding the piston rod 13 through the slot 51. The shroud 50 may be mounted to the barrel 12 with the guard barrel mount 55 in contact with, for sliding along, the barrel 12. The guard eye mount 44 is aligned over the rod eye 14, such that the lower guard eye mount surface 58 contacts the eye mount surface 25 and the guard aperture 57 is aligned over the spacer counterbore 26. The retention system 42 may then be mounted to the cylinder 11 and cylinder guard 41 so as to secure and hold the cylinder guard 41 to the cylinder 11. The isolator 80, if present, may be secured around the spacer 60 and may, in particular, be mounted around the second spacer portion 64 adjacent to the first spacer portion 63. The spacer 60 may be inserted through the guard aperture 57 and spacer counterbore 26 so that the second spacer portion 64 abuts the spacer mounting surface 28 and the first spacer portion 63 abuts the guard eye mount 44, particularly the upper guard eye mount surface 59. The isolator 80 may thus be secured between the first spacer portion 63 and the guard eye mount 44. The fastener 70 may then be inserted through the spacer aperture 62 and into the fastener bore 27. Therefore, the fastener 70 contacts the spacer 60 and, by transmitting forces through the spacer 60 (since the fastener 70 may not contact any part of the cylinder guard 41 itself), holds the cylinder guard 41 against the rod eye 14 in the mounted configuration. When the cylinder 11 is subsequently used and the piston rod 13 is extended and retracted, the shroud 50 may protect and cover or overlie the piston rod 13 and at least part of the barrel 12. In the extended configuration of Figure 1, the shroud 50 extends over the entire length of the piston rod 13 and a small part of the barrel 12. However, in the retracted configuration of Figure 4, in which the piston rod 13 is substantially entirely within the barrel 12 (except for the rod eye 14), the shroud 50 overlies the majority of the length of the barrel 12 and the piston rod 13 retracted therein. In the mounted configuration, the retention system 42 is offset from the rod eye central axis 22 and may be located between the rod eye central axis 22 and rod eye inner edge 30 and / or flat portion 23. The spacer and fastener axes 65, 75 are coaxial. The spacer and fastener axes 65, 75 may be perpendicular to and may be offset from, such that they do not intersect, the rod eye aperture central axis 22. In particular, the spacer and fastener axes 65, 75 may extend between the rod eye aperture central axis 22 and rod eye inner edge 30 and / or flat portion 23. The spacer and fastener axes 65, 75 may, however, intersect and be perpendicular to the axis of extension of the piston rod 13. As described hereinbelow, the cylinder guard 41 and retention system 42 are configured such that, in the mounted configuration, the cylinder guard 41 can move relative to the rod eye 14 within a float range. The movement of the cylinder guard 41 relative to the rod eye 14, whilst the cylinder guard 41 and rod eye 14 are fastened together by the fastener 70 such that they cannot be separated without removing the fastener 70, is referred to herein as float. This float is beneficial because it enables the cylinder guard 41 to receive impacts and move to some extent around the fastener 70 in response to those impacts. The float range is the amount of movement available to the cylinder guard 41 when fastened and secured by the fastener 70 to the rod eye 14 in the mounted configuration. In other words, the cylinder guard 41 cannot be removed from the rod eye 14, but it can move within the float range relative to the rod eye 14. Figure 9 illustrates the available movements of the cylinder guard 41 relative to the rod eye 14 in the float range, including: Longitudinal movement up and down along the spacer and fastener axes 65, 75; - Transverse movement right and left parallel to the rod eye aperture central axis 22 and perpendicular to the spacer and fastener axes 65, 75; Fore-aft movement along the direction of extension of the cylinder 11 and perpendicular to the rod eye aperture central axis 22 and spacer and fastener axes 65, 75; Roll, in which the cylinder guard 41 can roll around the piston rod 13 (i.e. around the axis of fore-aft movement direction); Pitch, in which the cylinder guard 41 can pitch fore and aft (i.e. around the axis of transverse movement); and / or - Yaw, in which the cylinder guard 41 can rotate around the spacer and fastener axes 65, 75. Each of the available movements may be restricted and / or allowed based up the design of the cylinder guard assembly 40, particularly of the spacer 60 and the guard aperture 57. the cylinder guard assembly 40 may comprise a plurality of spacers 60 having different dimensions and / or materials for enabling different movements of the cylinder guard 41 relative to the cylinder 11. The operator may select a certain spacer 60 as necessary for the application, such as providing more or less float as required. The cylinder guard assembly 40 may also comprise a plurality of cylinder guards 41, each having different diameters of guard aperture 57, for example. The height of the spacer 60 (i.e. dimension along the spacer axis 65) may control the longitudinal movement in the float range. The cylinder guard assembly 40 may comprise a spacer 60 having a height above a predetermined height for providing a float range with longitudinal movement above a predetermined longitudinal movement. The cylinder guard assembly 40 may also comprise a spacer 60 having a height below a predetermined height for providing a float range with longitudinal movement below a predetermined longitudinal movement. The difference between the outer diameter of the spacer 60 (i.e. outer diameter of the second spacer portion 64) and inner diameter of the guard aperture 57 may control the movement of the cylinder guard 41 radially away from the spacer and fastener axes 65, 75 (i.e. the fore-aft movement and / or transverse movement) in the float range. In particular, the cylinder guard assembly 40 may comprise a spacer 60 with an outer diameter that is substantially the same as an inner diameter of a guard aperture 57 of a cylinder guard 41 thereof such that the movement of the cylinder guard 41 radially away from the spacer and fastener axes 65, 75 is below a predetermined value. The cylinder guard assembly 40 may also comprise a spacer 60 with an outer diameter that is less than a guard aperture 57 of a cylinder guard 41 thereof such that the movement of the cylinder guard 41 radially away from the spacer and fastener axes 65, 75 is above a predetermined value. In other words, the diameter of the guard aperture 57 may be greater than the outer diameter of the spacer 60, particularly the second spacer portion 64, thereby allowing movement therebetween. The pitch of the cylinder guard 41 may be controlled by adjusting the height of the spacer 60, the outer diameter of the spacer 60, inner diameter of the guard aperture 57 and / or the length of the at least one low friction contact pad 56. The yaw of the cylinder guard 41 may be adjustable to a relatively small extent, such as by adjusting the shroud 51 such that it contacts the rod eye 14. The roll of the cylinder guard 41 may be controlled by adjusting the height of the spacer 60, outer diameter of the spacer 60 and / or the width of the guard eye mount 44. The use of the spacer 60 allows for the fastener 70 to have sufficient preload, particularly in the case of a bolted joint. However, the spacer 60 also enables for there to be some float by the cylinder guard 41 in the mounted configuration, by virtue of some flex and / or elasticity in the spacer 60 (and isolator 80 if present). The first spacer portion 63 may in particular allow some movement and support of the shear load resulting from the repetitive movement of the cylinder 11 between its extended and retracted positions. Therefore, the risk of shearing of the fastener 70 at the joint is significantly reduced, ensuring that after an initial impact the cylinder guard 41 remains in place and protecting the cylinder 11 during subsequent impacts. However, the fastener 70 properties may be selected so that it shears at a predetermined load and the cylinder guard 41 detaches. The predetermined load may be selected based upon an impact force that significantly damages the cylinder guard 41 such that it can no longer protect the cylinder 11 and / or at which the cylinder guard 41 is bent to a sufficient extent that it would damage the cylinder 11 itself unless it breaks away. Furthermore, the material of the spacer 60 may be selected to provide the direction and / or amount of float required for a particular application. Different materials with different elasticities may also be selected accordingly. If the spacer 60 comprises metal or another rigid material, adjusting the spacer aperture 62 sizes and / or spacer 60 height will be the main method for controlling the float motion. However, if the spacer 60 comprises a deformable material, tolerances of the spacer aperture 62, spacer 60 and guard aperture 57 can be tightened.

Claims

1. A cylinder guard assembly for mounting to a cylinder comprising a piston rod extending from a barrel to a rod eye, wherein the cylinder guard assembly comprises:a cylinder guard comprising a guard eye mount for mounting the cylinder guard to the rod eye in a mounted configuration, the guard eye mount comprising a guard aperture therethrough; anda retention system comprising:a spacer configured to extend through the guard aperture to the rod eye in the mounted configuration; anda fastener configured to, in the mounted configuration, fasten the cylinder guard and spacer to the rod eye,wherein the cylinder guard and retention system are configured such that, in the mounted configuration, the cylinder guard can move relative to the rod eye within a float range.

2. The cylinder guard assembly of claim 1 wherein the spacer comprises a first spacer portion configured to be mounted on the opposing side of the guard eye mount to the rod eye in the mounted configuration.

3. The cylinder guard assembly of claim 1 or claim 2 wherein the spacer comprises a second spacer portion configured to be mounted in the guard aperture in the mounted configuration.

4. The cylinder guard assembly of claim 2 and claim 3 wherein:the second spacer portion is adjacent to the first spacer portion in the mounted configuration and the first spacer portion has a greater outer diameter than the second spacer portion;the spacer extends along a length along a spacer axis, wherein the length of the first spacer portion is less than the length of the second spacer portion;the outer diameter of the spacer in the guard aperture is less than the inner diameter of the guard aperture; and / orthe first and second spacer portions are joined together such that the spacer is unitary or the first and second spacer portions are separate from each other.

5. The cylinder guard assembly of any preceding claim wherein the rod eye comprises an eye mount surface and the guard eye mount is configured to be flush with the eye mount surface in the mounted configuration.

6. The cylinder guard assembly of any preceding claim wherein the rod eye comprises a spacer counterbore extending into the rod eye, wherein the spacer is configured to, in the mounted configuration, extend through the guard aperture into the spacer counterbore.

7. The cylinder guard assembly of claim 6 wherein the spacer counterbore extends into the rod eye from the eye mount surface.

8. The cylinder guard assembly of claim 6 or claim 7 wherein the rod eye comprises a fastener bore extending into the rod eye from the spacer counterbore.

9. The cylinder guard assembly of any preceding claim wherein the fastener comprises a bolt configured to extend through the spacer for engagement with a thread of the rod eye.

10. The cylinder guard assembly of any preceding claim wherein the cylinder guard comprises a shroud, wherein the shroud extends from the guard eye mount to a guard barrel mount, the guard barrel mount being slidably mounted to the barrel in the mounted configuration such that the guard barrel mount can slide along the barrel as the piston rod extends and retracts from the barrel.

11. The cylinder guard assembly of any preceding claim wherein the spacer is one of a plurality of spacers of the retention system, the plurality of spacers comprising different dimensions and / or material(s) for providing different float ranges of movement of the cylinder guard relative to the rod eye.

12. The cylinder guard assembly of any preceding claim wherein the retention system further comprises an isolator configured to be mounted between the spacer and the cylinder guard.

13. A cylinder assembly comprising:a cylinder comprising a piston rod extending from a barrel to a rod eye; and a cylinder guard assembly comprising:a cylinder guard comprising a guard eye mount mounting the cylinder guard to the rod eye in a mounted configuration, the guard eye mount comprising a guard aperture therethrough; anda retention system comprising:a spacer configured to extend through the guard aperture to the rod eye in the mounted configuration; anda fastener configured to, in the mounted configuration, fasten the cylinder guard and spacer to the rod eye, wherein the cylinder guard and retention system are configured such that, in the mounted configuration, the cylinder guard can move relative to the rod eye within a float range.

14. A method of assembling a cylinder assembly, the method comprising mounting a cylinder guard assembly to a cylinder, the cylinder comprising a piston rod extending from a barrel to a rod eye, wherein mounting the cylinder guard assembly to the cylinder comprises:mounting a guard eye mount of a cylinder guard of the cylinder guard assembly to the rod eye, the guard eye mount comprising a guard aperture therethrough; andmounting a retention system of the cylinder guard assembly to the cylinder guard and cylinder by:inserting a spacer to extend through the guard eye mount to the rod eye;andfastening the cylinder guard and spacer to the rod eye by a fastener, wherein such that, when mounted, the cylinder guard can move relative to the rod eye within a float range.

15. The method of claim 14 further comprising selecting the spacer from a plurality of spacers, the plurality of spacers comprising different dimensions and / or material(s) for providing different float ranges of movement of the cylinder guard relative to the rod eye .19

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