Suspension fork seal head for enhanced component lubrication

Abstract

The present disclosure provides a spring fork comprising a fork leg, which includes an upper tube and a lower tube that are in sliding engagement with each other for compression and rebound; a damper assembly positioned in the fork leg, the damper assembly comprising a shaft and a sealing head coupled to the shaft; and a reservoir configured to hold bath oil near the sealing head. The sealing head is dimensioned and positioned to fling the bath oil upwards when the sealing head is driven into the bath oil during compression of the spring fork. The sealing head comprises a base section and a front section that tapers downwards from the neck. The hydrodynamic profile of the sealing head generates controlled oil displacement profiles by which lubricating oil is distributed to internal components, including bushings, seals, and sliding surfaces, during a suspension movement.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] This application claims priority over US patent application no. 19 / 344,646, filed on September 30, 2025, and further claims priority over US preliminary patent application no. 63 / 720,875, filed on November 15, 2024, entitled “Inverted Suspension Fork with Improved Air Spring and Lubrication”, the contents of which are incorporated herein by reference in their entirety. TECHNICAL AREA

[0002] The present disclosure relates generally to suspension systems for vehicles and in particular to spring forks and sealing heads therefor. BACKGROUND

[0003] Vehicle suspension systems, especially those used in bicycles and motorcycles, rely heavily on proper lubrication for effective operation and a long service life. Bath oil plays a crucial role in these systems by providing lubrication to various components, including bushings, seals, and sliding surfaces. In suspension forks, the bath oil reduces friction between moving parts, dissipates heat generated during operation, and helps prevent wear and corrosion. Most importantly, the oil creates a thin film between sliding surfaces, allowing for unimpeded movement and minimizing metal-to-metal contact.

[0004] This lubrication is particularly important in the dynamic environment of a suspension fork, where rapid and repetitive movements occur during compression and rebound. Without sufficient lubrication, increased friction occurs on the suspension components, leading to reduced performance, premature wear, and potential failure. Furthermore, the oil contributes to the overall damping characteristics of the suspension and influences how the fork reacts to shocks and vibrations. SUMMARY

[0005] Various embodiments of a spring fork with a sealing head optimized for flinging bath oil to lubricate internal components of a fork leg are disclosed. According to one aspect of the present disclosure, a spring fork is provided. The spring fork comprises a fork leg including an upper tube and a lower tube, which are in sliding engagement with each other for compression and rebound. The spring fork includes a damper assembly positioned in the fork leg, the damper assembly comprising a shaft and a sealing head coupled to the shaft. The spring fork includes a reservoir configured to hold bath oil near the sealing head, the sealing head being dimensioned and positioned to fling the bath oil upwards when the sealing head is driven into the bath oil during compression of the spring fork.

[0006] The sealing head can comprise a base section and a front section that tapers downwards. The sealing head can further comprise a neck with a diameter less than an adjacent section of the front section, the diameter of the neck being less than the diameter of the base section. The base section can be configured to connect with a cylinder positioned in the fork leg, and the shaft can extend through the cylinder. One bottom face of the sealing head can be flat.

[0007] The sealing head can have a first annular recess with an annular bushing positioned therein and a second annular recess with an annular seal positioned therein. The fork leg can comprise an upper tube, at least one bushing, and a foam ring, wherein the upper tube and / or the at least one bushing and / or the foam ring are coated with a quantity of the bath oil in response to the bath oil being flung through the sealing head.

[0008] The sealing head can have a base section, a front section, and an intermediate section positioned between the base section and the front section, wherein the base section has a diameter greater than that of the front section and the intermediate section combined and has downward-tapering edges, wherein the intermediate section has a uniform outer diameter, and the front section tapers downward from the intermediate section. The base section can taper downward toward the neck, and the front section can taper downward from the neck. The front section and / or the neck (if present) and / or the base section can have a concave surface. The spring fork can further comprise several machined features positioned in an annular arrangement around the uppermost edge of the front section.

[0009] According to another aspect of the present disclosure, a spring fork is provided. The spring fork comprises an upper tube. The spring fork comprises a lower tube which is in sliding engagement with the upper tube. The spring fork comprises a damper assembly positioned in the upper tube and / or the lower tube, wherein the damper assembly comprises a shaft and a sealing head coupled to the shaft, the sealing head being configured for translational movement with respect to the lower tube. The spring fork comprises a reservoir configured to hold bath oil, the sealing head comprising a base section and a front section tapering downward from the base section, the sealing head being configured to fling the bath oil upward when driven into the bath oil during compression of the spring fork.

[0010] The sealing head may further comprise a neck positioned between the base section and the front section, the neck having a diameter less than that of an adjacent section of the front section. The base section may have a U-shaped cross-section and may be configured to connect with a cylinder positioned in the upper tube and / or the lower tube. The sealing head may comprise a first annular recess with an annular bushing positioned therein, and a second annular recess with an annular seal positioned therein.

[0011] The fork leg can comprise an upper tube, at least one bushing, and a foam ring, wherein the upper tube and / or the at least one bushing and / or the foam ring are coated with a quantity of bath oil in response to the splashing of the bath oil by the sealing head. The base section can taper downwards towards the neck. The sealing head can have a base section, a front section, and an intermediate section positioned between the base section and the front section, wherein the base section has a diameter greater than that of the front section and the intermediate section combined, and has downward-tapering edges, wherein the intermediate section has a uniform outer diameter, and the front section tapers downwards from the intermediate section.

[0012] According to a further aspect of the present disclosure, a method is provided. The method comprises providing a spring fork, the spring fork comprising a fork leg, the fork leg comprising a shaft and a sealing head coupled to the shaft, and a reservoir holding bath oil near the sealing head. The method comprises, during compression of the fork leg, causing the bath oil to be flung upwards by means of the sealing head to lubricate an upper component of the fork leg. The upper component to be lubricated may include: an upper tube of the fork leg and / or at least one upper bushing and / or a foam ring.

[0013] This summary serves to present, in simplified form, a selection of concepts that are described in more detail below. The summary is not intended to identify key features or essential features of the claimed invention, nor is it intended to serve as an aid to interpreting the scope of protection of the claimed invention. The preceding general description of the exemplary embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and do not constitute a limitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Many aspects of this revelation can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale; the main focus is instead on clarifying the principles of the revelation. Furthermore, similar reference symbols for corresponding parts are used in all the different views of the drawings. Fig. Figure 1 is a front view of an upside-down type spring fork according to various embodiments of the present disclosure. Fig. Figure 2 is a front view of the upside-down type suspension fork from Fig. 1, shown fully compressed, according to various embodiments of the present disclosure. Fig. Figure 3 is a front view of the upside-down type suspension fork from Fig. 1, fully extended, according to various embodiments of the present disclosure. Fig. Figure 4 is a cross-sectional view of the upside-down type suspension fork. Fig. 1 according to various embodiments of the present disclosure. Fig. Figure 5 is a cross-sectional view of an upper section of the suspension fork of Fig. 1 according to various embodiments of the present disclosure. Fig. Figure 6 is a cross-sectional view of an upper section of a damper side of the suspension fork of Fig. 5 according to various embodiments of the present disclosure. Fig. Figure 7 is a cross-sectional view of a lower section of the damper side of the suspension fork of Fig. 4, which shows a profile of a sealing head according to various embodiments of the present disclosure. Fig. Figure 8 is another profile view of a sealing head according to various embodiments of the present disclosure. Fig. Figure 9 is yet another profile view of a sealing head according to various embodiments of the present disclosure. Fig. 10 and Fig. 11 are perspective views of the sealing head of Fig. 7 and Fig. 8 according to various embodiments of the present disclosure. Fig. Figure 12 is another profile view of a sealing head according to various embodiments of the present disclosure. Fig. Figure 13 is yet another profile view of a sealing head according to various embodiments of the present disclosure. Fig. Figure 14 shows another profile view of a sealing head according to various embodiments of the present disclosure. DETAILED DESCRIPTION

[0015] The present disclosure relates to a spring fork with a predetermined profile geometry optimized such that, when the sealing head is driven into an oil bath volume on an inner underside of the spring fork, bath oil is flung upwards with a suitable force to lubricate various internal components of the spring fork.

[0016] Inadequate lubrication can lead to a range of performance problems or potential component failure in suspension forks and other suspension systems. If lubrication is insufficient, increased friction can occur on the moving parts within the suspension system, resulting in reduced responsiveness, less smooth operation, and decreased rider comfort. The lack of proper lubrication can also cause accelerated wear on various components, such as bushings, seals, and sliding surfaces, potentially shortening the overall lifespan of the suspension system.

[0017] In some cases, inadequate lubrication in suspension systems can lead to a phenomenon known as "static friction," where static friction between components temporarily prevents smooth movement at the beginning of the suspension stroke. This can result in a jerky or inconsistent suspension action, which is particularly noticeable when encountering small bumps or vibrations. Furthermore, inadequate lubrication can contribute to increased heat buildup within the suspension system during operation, potentially degrading the performance of seals and other components over time. Proper lubrication is therefore crucial for maintaining optimal suspension performance, durability, and rider comfort across various types of terrain and driving conditions.

[0018] Accordingly, various embodiments of the present disclosure relate to a spring fork with a sealing head designed to optimize the lubrication of internal components. The spring fork comprises a fork leg, which includes an upper tube and a lower tube that are in sliding engagement with each other for compression and rebound. A damper assembly is positioned in the fork leg and includes a shaft with a sealing head coupled thereto. The spring fork also has a reservoir configured to hold bath oil near the sealing head. The sealing head is dimensioned and positioned to fling or otherwise force the bath oil upwards when it is driven into the bath oil during a movement (e.g., compression) of the spring fork.

[0019] In some embodiments, the sealing head may have a profile comprising a base section, a neck, and a front section that tapers downward from the neck. The neck may have a diameter smaller than that of an adjacent section of the front section. The sealing head may also have a U-shaped cross-section in the base section, a flat bottom surface, and annular recesses for bushings and seals. The geometry of the sealing head may contribute to the centrifugal effect. These components may work together to improve the sealing head's ability to effectively distribute lubricating oil within the suspension system.

[0020] The suspension fork design can be used in various configurations, including single-leg and dual-leg suspension systems on bicycles, motorcycles, e-bikes, etc. In a dual-leg system, one leg can house the damper assembly with its special sealing head, while the other leg can contain an air spring assembly. This arrangement allows for optimized performance and lubrication in both legs of the suspension system. The sealing head profile can contribute to improved overall suspension performance, durability, and ride comfort under various riding conditions and terrain.

[0021] Previous suspension fork designs incorporated various methods for directing and distributing bath oil to lubricate internal components. Some approaches may include oil channels, ports, or reservoirs strategically placed within the fork structure. However, these designs often rely on passive oil distribution or minimal oil movement during fork operation. While such systems may provide sufficient lubrication in some cases, they cannot fully optimize oil distribution to all critical components, particularly during dynamic riding conditions. In contrast, the sealing head described in this disclosure allows for an active approach to oil distribution.By specifically shaping and positioning the sealing head to fling bath oil upwards during compression, a more thorough and consistent lubrication of internal components can be achieved compared to conventional fork designs.

[0022] Referring now to the figures, Fig. 1, Fig. 2 and Fig. Three front views of a suspension system according to various embodiments. The suspension system comprises a spring fork 100. Although an upside-down type spring fork, designated as such, is shown in various figures, it is understood that the components and functions described herein can also be implemented with other types of spring forks (e.g., conventional non-upside-down spring forks) and suspension systems without deviating from the principles of the disclosure. Furthermore, it is understood that, although a two-legged spring fork 100 is shown, the principles described herein can be implemented in suspension systems with only one leg.

[0023] With reference to Fig. 1-3 The suspension fork 100 comprises upper tubes 103a, 103b (collectively "upper tubes 103") and lower tubes 106a, 106b (collectively "lower tubes 106"). A first lower tube 106a is in sliding engagement with a first upper tube 103a, and a second lower tube 106b is in sliding engagement with a second upper tube 103b. The sliding engagement may include a telescopic arrangement between the tubes 103, 106. In some aspects, the upper tubes 103 may have a diameter larger than the diameter of the lower tubes 106. However, in non-upside-down suspension forks, the lower tubes 106 may have a diameter larger than the diameter of the upper tubes 103.

[0024] The sliding engagement between the upper tubes 103 and the lower tubes 106 allows the suspension fork 100 to compress and extend (or rebound) as an operator (e.g., a rider) traverses varied terrain on a bicycle or similar vehicle. When the rider encounters bumps, obstacles, or uneven surfaces, the lower tubes 106 telescopically retract into the upper tubes 103, absorbing shocks and vibrations, or vice versa. This movement helps maintain tire contact with the ground, thereby improving traction and control. When the suspension fork 100 rebounds after compression, the lower tubes 106 extend back out of the upper tubes 103, preparing the suspension for the next impact.The sliding process between the upper tubes 103 and the lower tubes 106 can be facilitated by bushings, seals and lubricating oil (among other components) that work together to reduce friction and ensure consistent performance over the range of motion of the suspension fork 100.

[0025] The suspension fork 100 further comprises a steerer tube 109, a fork crown 112, and a thru-axle 115. The fork crown 112 can couple the upper tubes 103 together, and the thru-axle 115 can couple the lower tubes 106 together. Thus, an upper end of each of the upper tubes 103 can be coupled to the fork crown 112. The steerer tube 109 and the fork crown 112 can together form a fork crown-steerer tube assembly, and the steerer tube 109 can extend vertically from a central section of the fork crown 112.

[0026] The upper tubes 103 can be installed with the fork crown-steerer tube assembly by press fit or clamping bolts. The suspension fork 100 can be attached to the head tube of a bicycle, motorcycle, or other two- or three-wheeled vehicle by means of a set of headset bearings inside the steerer tube 109 and steered by a handlebar assembly screwed onto the stem. This configuration can provide a secure connection between the suspension fork 100 and a vehicle frame while also allowing for smooth steering control.

[0027] The 115mm thru-axle can be used to secure the 100mm suspension fork to a vehicle. For example, the 115mm thru-axle can be guided through the hub of a vehicle wheel, including, among others, the front wheel of a bicycle or motorcycle. Fig. 1 The suspension fork 100 comprises lower protective devices 118a, 118b (together ‘lower protective devices 118’) which cover the lower tubes 106 and protect the lower tubes 106 from dirt, impact and other damaging forces. However, the lower protective devices 118 have been shown in the illustration for clarity. Fig. 2 and Fig. 3 omitted. The lower protective devices 118 can be detachably attached to the spring fork 100 in some embodiments or can be integral with the upper tubes 103.

[0028] The upper tubes 103, the lower tubes 106, and the steerer tube 109 can each be constructed from various materials, chosen to ensure an optimal balance between strength, weight, and performance characteristics. In some implementations, these components, along with other components of the 100 series suspension fork, can be manufactured from high-strength aluminum alloys that offer excellent stiffness-to-weight ratios and corrosion resistance.

[0029] Carbon fiber composites can also be used, particularly for the steerer tube 109 and the upper tubes 103, to further reduce weight while maintaining structural integrity. In other cases, the lower tubes 106 can be made of steel alloys to increase durability and withstand the stresses of repeated compression and rebound cycles. High-end fork designs may utilize titanium alloys, which offer a combination of low weight, high strength, and vibration damping. The materials for each component can be selected to meet specific performance requirements, as well as according to rider preferences and the intended use of the 100 suspension fork.

[0030] Fig. Figure 2 shows the suspension fork 100 at full compression, representing the maximum travel of the suspension fork 100, in which the lower tubes 106 are fully telescopically retracted into the upper tubes 103. At full compression, a sealing head (not shown), positioned on a damper side of the suspension fork 100 as described, can be in its lowest position or closest to the bottom of the suspension fork 100, where bath oil is stored.

[0031] Fig. 2 represents an extreme end of the travel range of the 100 suspension fork, which typically occurs during significant impacts or landings after drops from a great height. Fig. Figure 3 shows the suspension fork 100 in full extension. In this position, the lower tubes 106 extend from the upper tubes 103 to their maximum length, which is one of the Fig. Figure 2 shows the opposite end of the travel range to the full compression of the suspension. This often occurs when the vehicle is unloaded or not in use, or when the suspension rebounds after absorbing an impact. The Fig. 3 shown position of the full extension and the one in Fig. The two positions shown, representing the full compression of the suspension, together represent the maximum available travel of the 100 mm suspension fork.

[0032] With reference to the following Fig. 4 shows Fig. Figure 4 shows a cross-sectional view of the suspension fork 100, illustrating various internal components. The suspension fork 100 can include a damper strut 121, which comprises the first upper tube 103a, the first lower tube 106a, and a damper assembly 122 positioned within the damper strut 121. The suspension fork 100 can further include an air spring strut 124, which comprises the second upper tube 103b and / or the second lower tube 106b. The damper strut 121 can also be referred to as a "damper side" of the suspension fork 100, and the air spring strut 124 can also be referred to as an "air spring side" of the suspension fork 100.

[0033] The in Fig. The configuration of the suspension fork 100 shown in Figure 4 represents a dual-chamber damper and air spring arrangement, which may be provided in high-performance upside-down suspension forks 100. The damper leg 121 may include the damper assembly 122 for controlling a rate of compression and / or rebound of the suspension fork 100 and providing adjustable damping characteristics to adapt to different riding conditions and preferences. The damper assembly 122 may include a rebound assembly 123, positioned in a lower section of the damper leg 121, and / or a compression assembly 125, positioned in the upper section of the damper leg 121, each adjustable to control rebound and compression, respectively. The damper leg 121 may further include, for example, an upper piston, a lower piston, and shim stacks (stacks of metal plates) to generate hydraulic resistance, among other components.

[0034] The air spring strut 124, on the other hand, is configured to provide a main spring force to the spring fork 100. The air spring strut 124 can supply pressurized gas to counteract compression and return the spring fork 100 to its extended position as shown in the illustration. Fig. 3. For this purpose, the air spring 124 can include a pressurized air chamber 127 and a vacuum air chamber 130, which are positioned within the walls of a cylinder defined by the upper tube 103b and / or the lower tube 106b. The pressurized air chamber 127 and the vacuum air chamber 130 can be adjusted throughout their travel range for fine-tuning the behavior of the suspension fork 100. By positioning these assemblies in separate legs of the fork, the design allows for optimal performance of each system without interference, while also distributing the functional components evenly across the suspension fork 100.

[0035] The damper assembly 122 can comprise a compression range 132, which includes the compression assembly 125, and a rebound range 134, which includes the rebound assembly 123. A compression adjustment device 136 can be positioned on the damper strut 121 to control the compression in the compression range 132. For example, the compression adjustment device 136 can be positioned on the fork bridge 112 above the first upper tube 103a and can be used to adjust or control desired characteristics of the damper strut 121 and / or its compression range 132. The compression adjustment device 136 can be integrated with or part of one or more end cap assemblies 138a, 138b (collectively, “end cap assemblies 138”). The cover cap assemblies 138 can be installed using a suitable tool, such as aan Allen key or similar tool, from the spring adjustment device 136.

[0036] The suspension adjustment device 136 can provide an interface for the driver or vehicle operator to fine-tune the suspension characteristics of the spring fork 100 or, more specifically, of the shock absorber 121 thereof. In some implementations, each suspension adjustment device 136 can include a dial or knob that a driver or other operator can manipulate to simulate various suspension parameters. By turning the dial clockwise or counterclockwise, the operator can increase or decrease the suspension damping, respectively.

[0037] The operator can adjust the compression damping using the compression adjustment device 136 to control how quickly the suspension fork 100 compresses under load. A firmer setting, achieved, for example, by turning the dial clockwise, can provide greater resistance to compression, which can be advantageous on smoother terrain or when the rider desires a more responsive feel. Conversely, a softer setting, achieved, for example, by turning the dial counterclockwise, can allow for easier compression, thereby improving sensitivity to small bumps and traction on uneven terrain.

[0038] In some embodiments, the suspension adjustment device includes 136 detent or click positions that provide tactile feedback to the operator and allow for more precise and repeatable adjustments. In addition, the suspension adjustment device may include 136 visual indicators, such as numbered markers or color-coded areas, which can help drivers track and repeat their preferred settings for different driving conditions.

[0039] The damper strut 121 and / or the air spring strut 124 may include various bushings, such as upper bushings 140a, 140b (collectively “upper bushings 140”), lower bushings 142a, 142b (collectively “lower bushings 142”), etc. The upper bushings 140 may be positioned near the top of the lower tubes 106, while the lower bushings 142 may be positioned near the bottom of the upper tubes 103. Together, these bushings 140, 142 facilitate the sliding motion between the upper tubes 103 and the lower tubes 106, thereby reducing friction and ensuring proper alignment throughout the travel range of the suspension fork 100.

[0040] The bushings 140, 142 can be made of low-friction materials, such as polytetrafluoroethylene (PTFE) or other special polymers designed to withstand the dynamic loads and environmental conditions to which the suspension fork 100 is subjected. The bushings 140, 142 can distribute forces evenly across the sliding surfaces, thereby preventing metal-to-metal contact between the upper tubes 103 and the lower tubes 106. This reduces wear, extends the service life of the suspension fork 100, and contributes to a smoother and more responsive suspension action.

[0041] The air spring strut 124 may include an air piston 144 coupled to an air shaft 146, which allows the transfer of air pressure between the pressurized air chamber 127 and the vacuum air chamber 130. The air shaft 146 may be hollow in some implementations and solid in others. The air piston 144 may move translationally or otherwise within the cylinder in response to compression and extension of the spring fork 100. In some implementations, the air shaft 146 may extend from the air piston 144 to the upper portion of the spring fork 100 and pass through the vacuum air chamber 130. This may allow air transfer between chambers during the spring stroke, thus providing suspension characteristics. The air piston 144 and the air shaft 146 may include seals to maintain proper air pressure separation between chambers and prevent unwanted air loss.

[0042] With reference to the damper strut 121, the damper strut 121, as previously stated, can, according to various embodiments, comprise a compression range 132 and / or a rebound range 134. The compression range 132 can comprise a compression assembly 125, which can cooperate with the compression adjustment device 136 to regulate the rate at which the suspension fork 100 compresses under load, thereby allowing riders to fine-tune the response of the suspension fork 100 to shocks and terrain variations based on their preferences and riding conditions. Likewise, the rebound range 134 can comprise a rebound assembly 123, which controls the rate at which the suspension fork 100 extends after compression.The rebound arrangement can be adjusted using a rebound adjustment device and cap assembly 150, which is positioned at the bottom of the leg of the suspension fork 100, allowing riders to fine-tune the return speed of the suspension fork 100 to adapt to different riding conditions and personal preferences.

[0043] Referring initially to the compression section 132, the compression section 132 can generally include, among other components, a compression piston 152 coupled to a compression piston shaft 154. The compression piston 152 moves translationally via the compression piston shaft 154 vertically in the upper tube 103. Thus, the compression piston 152 can be configured to move within a damper tube 156, thereby counteracting the compression of the suspension fork 100. A spring 158 can be positioned around the compression piston shaft 154 and provide additional control of the compression and rebound characteristics in the compression section 132. The compression piston shaft 154 can extend through the damper strut 121 and move translationally within it.

[0044] Referring to the extension section 134, the extension section 134 can also include, among other components, an extension piston 160 coupled to an extension damper shaft 162. In some scenarios, the extension damper shaft 162 can be part of a rod assembly. Furthermore, the extension assembly 123 can include a cylinder 164, wherein the extension piston 160 moves translationally within the cylinder 164 to control the extension of the spring fork 100. In some embodiments, the extension damper shaft 162 can include a needle section 166.

[0045] A sealing head 168 can be positioned in the damper strut 121 along the rebound damper shaft 162 and can act as a seal, sealing the cylinder 164. Thus, the sealing head 168 can form a connection with a lower end of the cylinder 164 to prevent, for example, the escape of fluid (e.g., oil). In some embodiments, the sealing head 168 includes a base with a U-shaped cross-section and a thread 169 at the lower end of the cylinder 164. However, it is understood that the sealing head 168 can form other types of connections with the cylinder 164, including a press fit, a friction fit, etc.

[0046] In some implementations, the rebound damper shaft 162 and the rebound piston 160 attached to it can remain fixed to the lower tube 106a during compression and rebound. For example, the lower tube 106a can move telescopically into the upper tube 103a during compression of the fork 100, which can cause the rebound piston 160 to move in the view of Fig. 4 moved upwards into the upper tube 103a. When the suspension is fully compressed, the rebound piston 160 is positioned relatively close to the compression area 132 (and to the compression piston 152 thereof).

[0047] In contrast, during rebound the lower tube 106a can extend out of the upper tube 103a or move telescopically, and the cylinder 164 can move downwards and into the space in relation to the rebound piston 160. Fig. The position shown in Figure 4, in which the spring fork 100 is in full extension or rebound, can move. The sealing head 168, which is connected to the lower end of the cylinder 164, can move together with the cylinder 164 during compression and rebound cycles. This arrangement allows the damping characteristics to be controlled by the relative movement between the rebound piston 160 and the moving cylinder 164, with the sealing head 168 maintaining a fluidic seal throughout the entire range of movement.

[0048] Generally, a sealing head 168 only seals the lower end of the cylinder 164. However, according to various embodiments of the present disclosure, the sealing head 168 can have a specific geometry to optimize and enhance the centrifugation of the bath oil, so that the internal components of the spring fork 100 remain lubricated, as described. Furthermore, the sealing head 168 is dimensioned and positioned to provide a fluid flow path for the bath oil when it is contacted by the sealing head 168 or during other oil distribution events.

[0049] With reference to the following Fig. 5 and Fig. 6 shows Fig. 5 a cross-sectional view of an upper section of the suspension fork 100 of Fig. 4 and shows Fig. 6 An upper cross-sectional view of an upper section of the damper leg 121 of the spring fork 100. First, with reference to Fig. 5 angles that are used as frame downtube angles for frame downtubes f d1 and f d2 The fork 100 can be dimensioned and positioned to provide sufficient clearance between the compression adjustment device 136, the end cap assemblies 138, vent valve assemblies, etc., and the frame downtubes f. d1 and f d2 to provide clearance when the fork is rotated 90 degrees, for example. This clearance can help prevent disruptive interference or contact between these components during steering maneuvers, especially in sharp turns.

[0050] The suspension fork 100 can comprise one or more cover cap assemblies 138, such as a first cover cap assembly 138a and a second cover cap assembly 138b. With reference to Fig. 5 and Fig. In the illustration, the first end cap assembly 138a is positioned in or on a first upper tube 103a, and the second end cap assembly 138b is positioned in or on a second upper tube 103b. The end cap assembly 138 can be screwed onto the upper tube 106 or another section of the suspension fork 100. Thus, the end cap assembly 138 can be removed using a screwdriver, Allen wrench, or similar tool.

[0051] It is understood, however, that other connection types can be used to couple the cover cap assembly 138 to the tubes of the spring fork 100, such as a snap connection, a press connection, etc. In some embodiments, a first section of the cover cap assembly 138 is positioned outside the upper tube 103 (e.g., on an upper surface of the upper tube 103), while a second section of the cover cap assembly 138 is inserted into or positioned in the upper tube 103.

[0052] Continue with Fig. Figure 7, showing an enlarged section of a lower end of the damper leg 121 of the spring fork 100 according to various embodiments. In particular, the view of Fig. Figure 7 shows the upper tube 103a and the lower tube 106a in full compression, which is also referred to as a bottom-out event. When, during a bottom-out event or near-bottom-out event, the damper strut 121 is compressed and the lower tube 106a moves telescopically into the upper tube 103a, the sealing head 168 approaches a lower end of the damper strut 121, as shown in Figure 7. Fig. 7 is shown.

[0053] On the damper side of the spring fork 100, it may be desirable to configure the sealing head 168 so that it supplies oil from an oil bath in an upward direction D1 to one or more of the upper bushings 140 ( Fig. 4) or the lower bushings 142 and a ring 170, so that the components are regularly and sufficiently lubricated. The ring 170 can, for example, comprise a foam ring or a ring made of another material. The foam ring 170 can, for example, absorb bath oil and thus lubricate an outer surface of the leg tubes when it passes along the foam ring 170 during compression and rebound.

[0054] Accordingly, in various embodiments a sealing head 168 with a predetermined profile is described which, when driven into an oil bath volume at the inner bottom of the spring fork 100, causes oil to be flung upwards to lubricate various internal components of the spring fork 100.

[0055] Fig. Figure 7 shows a cross-section of the cylinder 164, which, depending on the compression state of the spring fork 100, can be arranged in the lower tube 106a and / or the upper tube 103a. The cylinder 164 can include a reservoir 172 containing oil, and the sealing head 168 can selectively restrict or completely eliminate the escape of oil contained in the reservoir 172 from a bottom side of the cylinder 164.

[0056] The cylinder 164 can be positioned in or around a quantity of bath oil 174, which can be contained in a reservoir 176 defined by the cylindrical walls of the lower tube 106a. In some embodiments, the sealing head 168 can be detachably attached to a lower end of the cylinder 164. Thus, in some embodiments, the sealing head 168 can form a screw connection (or another suitable type of connection) with the cylinder 164. The screw head 168 can move in accordance with the cylinder 164 during a translational movement of the lower tube 106a relative to the upper tube 103a.

[0057] Referring to the cross-sectional view of the sealing head 168, in Fig. Figure 7 shows the profile of the sealing head 168. In some implementations, the sealing head 168 may comprise a base section 178, a neck 180, and a front section 182. The neck 180 may couple the base section 178 to the front section 182, and thus the base section 178 may be coupled to and directly adjacent to a first side of the neck 180, while the front section 182 may be coupled to and directly adjacent to a second, opposite side of the neck 180. In alternative geometries of the sealing head 168, no neck 180 is provided, as discussed.

[0058] In the specific arrangement of Fig. In section 7, the base section 178 is positioned vertically above the neck 180 and the front section 182, and likewise, the front section 182 is positioned vertically below the base section 178. However, it is understood that this orientation can vary based on the orientation of the spring fork 100.

[0059] The neck 180 may have a diameter less than that of the base section 178 and / or the front section 182. Thus, the neck 180 is recessed with respect to the outer surface of the base section 178 and / or the front section 182. In some embodiments, the neck 180 and / or a lower portion of the base section 178 may together comprise a recess 184 configured to receive and retain a bushing 186. The recess 184 may include an annular groove surrounding the shaft 162, and the bushing 186 may include an annular bushing dimensioned and positioned to fit within the recess 184 and engage with the shaft 162. The diameter of the base section 178, the neck 180, and the front section 182 may each be less than the inner diameter of the lower tube 106a.As a result of this, as well as the geometry of the sealing head 168, a fluid flow path is created that ensures sufficient centrifugation of the bath oil to promote lubrication.

[0060] As in Fig. As shown in Figure 7, a cross-section of the base section 178 can be U-shaped, such that outer walls overlap a lower end of the cylinder 164, thereby enabling a seal between the sealing head 168 and the cylinder 164. The front section 182 of the sealing head 168 extends downwards to a lower end of the damper leg 121. In some embodiments and as shown in Figure 7, the cross-section of the base section 178 can be U-shaped, such that outer walls overlap a lower end of the cylinder 164, thus enabling a seal between the sealing head 168 and the cylinder 164. The front section 182 of the sealing head 168 extends downwards to a lower end of the damper leg 121. In some embodiments and as shown in Figure 7, the sealing head 168 can be U-shaped. Fig. 7 The front section 182 has a section adjacent to the neck 180 with a diameter greater than that of the neck 180, and the front section 182 extends vertically downwards and then tapers downwards from this vertical extension. A lower end or bottom surface 189 of the sealing head 168 can generally be flat and / or uniform, which can promote centrifugal force.

[0061] In some embodiments, the sealing head 168 may further comprise a further recess 190, which in some embodiments may be located in the front section 182. The recess 190 may comprise an annular depression configured to receive and retain a seal 192, such as an annular flat gasket or another type of seal. Thus, the seal 192 can engage with the shaft 162 while positioned in the sealing head 168.

[0062] In some implementations, the level 193 of the bath oil 174 in the reservoir 176 can, depending on the configuration, rise above the sealing head 168 when the suspension fork 100 is fully or nearly fully compressed. In any case, as the lower tube 106a moves telescopically into the upper tube 103a, the volume available for the bath oil 174 in the reservoir 176 can decrease, causing the oil level to rise. This rising oil level can cover at least a portion of the sealing head 168, including the front section 182 and the neck 180. The immersion of the sealing head 168 in the bath oil 174 during compression can enhance the centrifugal effect, as the sealing head 168 displaces a larger volume of oil as it moves through the higher oil level.This can contribute to a more effective distribution of the bath oil 174 to the upper components of the spring fork 100, thereby ensuring thorough lubrication of bushings, seals and other components even during extreme compression events.

[0063] With reference to Fig. Figure 8 shows an alternative embodiment of the sealing head 168. As previously described, the sealing head 168 can comprise a base section 178, a neck 180, and a front section 182, each having distinctive geometries that can improve the oil sling and sealing capabilities of the sealing head 168. In the embodiment shown in Fig. In the embodiment shown in Figure 8, the base section 178 of the sealing head 168 can comprise a linear outer surface that tapers downwards from the cylinder 164 to the neck 180. This tapered design can create a transition between the cylinder 164 and the neck 180, reducing turbulence in the oil flow during compression and rebound cycles while simultaneously providing a fluid flow path. Despite the tapering, the base section 178 can maintain a diameter greater than that of the neck 180 along its length, thus providing structural integrity and ensuring a secure connection with the cylinder 164.

[0064] The neck 180 can serve as a transition area between the base section 178 and the front section 182. The neck 180 can have a reduced diameter compared to both adjacent sections, thereby creating recessed areas that could affect the oil flow dynamics and the fluid flow path during compression and rebound movements of the suspension fork 100.

[0065] The front section 182 can include a linear taper that narrows downwards from the neck 180 to the shaft 162. This gradual reduction in diameter can aid in guiding the oil flow and contribute to the centrifugal action as the sealing head 168 moves through the bath oil. The front section 182 can maintain a diameter greater than that of the neck 180 and the shaft 162 along its entire length. This configuration creates a stepped profile that influences the oil displacement and distribution profiles within the spring fork 100.

[0066] The linear tapers of the base section 178 and the front section 182, together with a relatively flat or planar bottom surface 189, optimize oil flow and fling characteristics. As the sealing head 168 moves through the bath oil, these surfaces can cause fling and help guide the oil flow in desired profiles, thereby improving the lubrication of internal components in the spring fork 100. In some embodiments, the transition points between the base section 178, the neck 180, and the front section 182 can be rounded or chamfered to further improve the oil flow characteristics and reduce potential stress concentrations in the structure of the sealing head 168.

[0067] This alternative design of the sealing head 168 can offer different performance characteristics compared to other configurations and allows for fine-tuning of oil distribution and damping characteristics in the 100 suspension fork. The specific angles of the tapers and the relative diameters of each section can be adjusted to achieve desired performance characteristics for different riding conditions or configurations of the 100 suspension fork.

[0068] In some embodiments, the front section 182 of the sealing head 168 may include machined features 194 arranged in an annular pattern around an outer surface of the sealing head 168, optionally at a location near the neck 180, such as an upper edge of the front section 182. The machined features 194 may include minor depressions in the surface of the front section 182. In this example, the machined features 194 act as flats for a wrench, providing a flat surface for a wrench, socket, or similar tool to form a gripping or other connection with an outer surface of the sealing head 168 for tightening or loosening the sealing head 168 to or from the cylinder 169 or other component.

[0069] In some embodiments, the machined features 194 can provide fluid flow characteristics for the sealing head 168. For example, as the sealing head 168 moves through the bath oil during compression and rebound cycles, the machined features 194 can interact with the oil flow and generate localized turbulence or guide oil in specific profiles. In some embodiments, the size, shape, and arrangement of the machined features 194 can be varied to achieve other fluid flow characteristics, thus allowing further individual adjustment of the sealing head 168's performance under different driving conditions.

[0070] For example, in some embodiments, the sealing head 168 may include helical patterns (not shown) formed on its outer surface, which can generate helical fluid flow paths that improve oil distribution during compression and rebound cycles. The helical patterns may be machined or otherwise formed on the surface of the front section 182, the neck 180, or the base section 178 to generate controlled turbulence and flow direction of the bath oil 174. Furthermore, the sealing head 168 may include recesses or holes extending through the body of the sealing head 168, allowing fluid to be guided through internal passages in the sealing head 168. The recesses may be strategically positioned to allow oil flow from one side of the sealing head 168 to the other, thereby creating additional pathways for lubricant distribution.

[0071] With reference to Fig. Figure 9 shows another alternative embodiment of the sealing head 168. The embodiment of Fig. 9 has similarities with the embodiment of Fig. 8, however, includes the distinctive geometric features that can improve oil sling and sealing capabilities.

[0072] As in Fig. As shown in Figure 9, the base section 178 of the sealing head 168 comprises a concave outer surface that tapers downwards from the cylinder 164 to the neck 180. Likewise, the neck 180 can comprise a concave surface. The concave taper at the base section 178 can define a transition between the cylinder 164 and the neck 180. The front section 182 of Fig. 9 also includes a tapered concave outer surface that narrows downwards from the neck 180 to the shaft 162. This tapering can be compared to that in Fig. In the embodiment shown in Figure 8, this feature may be more pronounced, potentially improving the oil flow and contributing to a more focused centrifugal effect when the sealing head 168 moves through the bath oil. The combination of the tapered front section 182 with the concave neck 180 and the base section 178 creates a stepped profile that influences the oil displacement and distribution profiles within the spring fork 100.

[0073] In this embodiment, the machine-engineered features 194 are, in comparison to those described in Fig. 8 shown, smaller or less pronounced. The machined features 194 can be positioned on a section of the front section 182 closest to the neck 180. This positioning can still allow the attachment of a wrench, socket, or the like, while simultaneously permitting more differentiated interactions with the oil flow and guiding oil in specific profiles that are complementary to the overall geometry of the sealing head 168. The reduced protrusion of the machined features 194 can therefore lead to finer fluid flow characteristics, which may be advantageous under certain driving conditions or fork configurations.

[0074] The base surface 189 of the sealing head 168 can remain relatively flat or planar, as in previous embodiments, to promote centrifugal force. The transition points between the base section 178, the neck 180, and the front section 182 can harmonize seamlessly due to the concave and tapered profiles, further refining oil flow characteristics and reducing stress concentrations in the sealing head 168.

[0075] With reference to the following Fig. 10 and Fig. 11 is Fig. 10 an upper perspective view of the sealing head 168 and is Fig. 11 a lower perspective view of the sealing head 168. With reference to Fig. 10 and Fig. The sealing head 168 comprises an upper recess 202 and a lower recess 204, which are interconnected. The upper recess 202 has an internal thread 206 for coupling the sealing head 168 to the thread 169 of the cylinder 164.

[0076] With reference to Fig. Figure 12 shows a further alternative embodiment of the sealing head 168. In this embodiment, the sealing head 168 has a base section 178, a front section 182, and an intermediate section 208 positioned between the base section 178 and the front section 182. The base section 178 has a diameter larger than both the front section 182 and the intermediate section 208, with edges that taper downwards from the base section 178 to the intermediate section 208. A lip 210 is formed in the base section 178, extending from the intermediate section 208, by a difference in the outer diameter of the base section 178 and the intermediate section 208.

[0077] The intermediate section 208 has a uniform outer diameter that remains constant along its length, creating a cylindrical area between the tapered base section 178 and the tapered front section 182. Thus, the intermediate section 208 can provide a stable area for mounting seals, bushings, or other components while maintaining consistent clearances to surrounding structures. Furthermore, the intermediate section 208 can serve as a transition zone that influences oil flow profiles as the sealing head 168 moves through the bath oil during compression and rebound cycles.

[0078] The front section 182 tapers downwards from the intermediate section 208 without creating steps or lips, narrowing towards the base of the sealing head 168. This improves the hydrodynamic properties of the sealing head 168, contributing to the centrifugal effect as it moves through the bath oil. The combination of the tapered base section 178, the uniform intermediate section 208, and the tapered front section 182 creates a taper and step profile that optimizes oil displacement and distribution profiles within the spring fork 100.

[0079] With reference to Fig. Figure 13 shows a further alternative embodiment of the sealing head 168. In this embodiment, the sealing head 168 comprises the base section 178, which tapers downwards, forming a generally triangular area without edges or lips. The base section 178 extends to a cylindrical collar section 212 of the sealing head 168. The collar section 212 does not have a tapered diameter but instead has a uniform diameter. The collar section 212 may include plug pin recesses 214 configured to receive plug pin projections from a plugging tool, thereby facilitating the installation of the sealing head 168 on the thread 169 of the cylinder 164.

[0080] The triangular profile of the base section 178 provides a flow-optimized transition from the cylinder 164 to the collar section 212, thereby reducing flow resistance as the sealing head 168 moves through the bath oil 174. The uniform diameter of the collar section 212 provides a consistent interface for tools while maintaining structural integrity during installation and removal procedures.

[0081] In some embodiments, the pin recesses 214 are positioned on opposite sides of the collar section 212. The pin recesses 214 in the collar section 212 can be positioned diametrically opposite each other, thus allowing for even application of torque during installation. Although the pin recesses 214 are arranged according to the illustration in Fig. 13 are positioned in the side walls, they can be used in Fig. 14 are positioned along the base surface. In some embodiments, the plug pin recesses 214 may be dimensioned to support standard plug tool configurations, thus ensuring compatibility with commonly available installation tools.

[0082] Fig. Figure 14 shows another embodiment of the sealing head 168, in which the base section 178 tapers downwards, forming a generally triangular area without edges or lips. Thus, an upper section of the base section 178 has a diameter greater than a lower section of the base section 178. However, in the embodiment of Fig. 14 no collar section 212, and thus there is a pronounced edge defined by a bottom surface of the base section 178 at its transition to the rebound damper shaft 162. Although the plug pin recesses 214 according to the illustration of the embodiment of Fig. 13 are positioned in the side walls of the base section 178, the plug pin recesses 214 are in Fig. 14 positioned along the base surface, allowing connection with a plug tool for screwing the base section 178 to the cylinder 164 or other components.

[0083] The sealing head 168 can be constructed from various materials, selected to ensure optimal performance characteristics for the suspension fork 100, particularly in bicycle applications. In some embodiments, the sealing head 168 can be made of aluminum, which is lightweight and offers corrosion resistance and machinability. In other embodiments, the sealing head 168 can be constructed of stainless steel, which may be somewhat heavier than aluminum but offers strength and corrosion resistance to bath oil 174 and environmental influences. Additional materials that can be used for the sealing head 168 include metal and titanium alloys, which can offer a balance between low weight and high strength. The choice of material for the sealing head 168 can be based on factors such as…Weight requirements, operating environment, manufacturing considerations and desired performance characteristics of the 100 spring fork will be determined.

[0084] The features, structures, or properties described above can be combined in any suitable manner in one or more embodiments, and the features discussed in relation to the various embodiments can be interchangeable where possible. Numerous specific details are provided in the following description to achieve a comprehensive understanding of the embodiments of this disclosure. However, those skilled in the art know that the technical solution of this disclosure can also be practically implemented without one or more of the specific details, or that other methods, components, materials, and the like can be used. In other cases, well-known structures or modes of operation are not shown or are not described in more detail in order to avoid obscuring aspects of the disclosed embodiments.

[0085] Although relative terms such as "on" or "at," "under," "upper," and "lower" are used in the description to describe the relative relationship of one component to another, these terms are used in this description only for the sake of simplicity, for example, to indicate direction in an example shown in the drawings. If the device is turned upside down, it is understood that the "upper" component described above becomes a "lower" component. When a structure is "on" or "at" another structure, it is possible that the structure is integrally formed with another structure, or that the structure is "directly" attached to or on another structure, or that the structure is "indirectly" attached to or on the other structure via other structures.

[0086] In this description, terms such as "a", "an", "the", and "a" are used to indicate the presence of one or more elements and components. The terms "comprise", "include", "exist", "contain", and their variants are to be interpreted as open-ended and, unless otherwise specified in the appended claims, are to be understood as including further elements, components, etc., in addition to the elements, components, etc. already listed.

[0087] The terms "first," "second," etc., are used merely as labels and not as a limitation on the number of objects. It is understood that when multiple components are displayed, they can be referred to as a "first" component, a "second" component, and so on.

[0088] The terms "approximately" and "essentially," unless defined herein in conjunction with a specific range, percentage, or associated deviation measure, encompass at least some manufacturing tolerances between a theoretical design and a manufactured product or arrangement, such as the geometric design and tolerance criteria described in American Society of Mechanical Engineers (ASME®) Standard Y14.5 and related International Organization for Standardization (ISO®) standards. Such manufacturing tolerances are always included, as is apparent to the person skilled in the art, even when "approximately," "essentially," or related terms are not explicitly mentioned, even in conjunction with the use of theoretical terms such as geometric "perpendicular," "orthogonal," "vertex," "collinear," "coplanar," and others.

[0089] The embodiments of the present disclosure described above are merely possible examples of implementations presented for the sake of clarity in understanding the principles of the disclosure. Many variations and modifications can be made to the embodiment(s) described above without deviating from the essence and principles of the disclosure. All such modifications and variations are hereby included within the scope of protection of this disclosure and fall within the scope of protection of the following claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 19 / 344,646

[0001] US 63 / 720,875

[0001]

Claims

[1] Suspension fork comprising the following: a fork leg comprising an upper tube and a lower tube which are in sliding engagement with each other for compression and rebound; a damper assembly positioned in the fork leg, the damper assembly comprising a shaft and a sealing head coupled to the shaft; and a reservoir configured to hold bath oil near the sealing head, the sealing head being dimensioned and positioned to fling the bath oil upwards when the sealing head is driven into the bath oil during compression of the suspension fork. [2] Spring fork according to claim 1, wherein the sealing head comprises a base section and a front section that tapers downwards. [3] Spring fork according to claim 2, wherein the sealing head further comprises a neck having a diameter which is less than an adjacent section of the front section, wherein the diameter of the neck is less than a diameter of the base section. [4] Spring fork according to claim 3, wherein the base section is configured to form a connection with a cylinder positioned in the fork leg and the shaft extends through the cylinder. [5] Spring fork according to claim 3, wherein the sealing head comprises a bottom surface, wherein the bottom surface of the sealing head is flat. [6] Spring fork according to claim 1, wherein the sealing head has a first annular recess with an annular bushing positioned therein and a second annular recess with an annular seal positioned therein. [7] Spring fork according to claim 1, wherein the fork leg comprises an upper tube, at least one bushing and a foam ring, wherein the upper tube and / or the at least one bushing and / or the foam ring are coated with an amount of the bath oil in response to the splashing of the bath oil by the sealing head. [8] Spring fork according to claim 1, wherein the sealing head has a base section, a front section and an intermediate section positioned between the base section and the front section, wherein the base section has a diameter greater than the front section and the intermediate section and has edges tapering downwards, wherein the intermediate section has a uniform outer diameter and the front section tapers downwards from the intermediate section. [9] Spring fork according to claim 3, wherein the base section tapers downwards towards the neck and the front section tapers downwards from the neck. [10] Spring fork according to claim 9, wherein the front section and / or the neck and / or the base section has a concave surface. [11] Spring fork according to claim 2, which further comprises several first machined features positioned in an annular arrangement around an uppermost edge of the front section for tightening the sealing head to a damper tube cylinder and several second machined features facilitating spinning or navigating of the bath oil with respect to the sealing head. [12] Suspension fork comprising the following: an upper pipe; a lower tube that is in sliding engagement with the upper tube; a damper assembly positioned in the upper tube and / or the lower tube, wherein the damper assembly comprises a shaft and a sealing head coupled to the shaft, the sealing head being configured for translational movement with respect to the lower tube; and a reservoir configured to hold bath oil, wherein the sealing head comprises: a base section and a front section tapering downwards from the base section, wherein the sealing head is configured to fling the bath oil upwards when driven into the bath oil during compression of the suspension fork. [13] Spring fork according to claim 12, wherein the sealing head further comprises a neck positioned between the base section and the front section, the neck having a diameter that is less than an adjacent section of the front section. [14] Spring fork according to claim 12, wherein the base section has a U-shaped cross-section and is configured to form a connection with a cylinder positioned in the upper tube and / or the lower tube. [15] Spring fork according to claim 12, wherein the sealing head comprises a first annular recess with an annular bushing positioned therein and a second annular recess with an annular seal positioned therein. [16] Spring fork according to claim 12, wherein the fork leg comprises an upper tube, at least one bushing and a foam ring, wherein the upper tube and / or the at least one bushing and / or the foam ring are coated with an amount of the bath oil in response to the splashing of the bath oil by the sealing head. [17] Spring fork according to claim 13, wherein the base section tapers downwards towards the neck. [18] Spring fork according to claim 12, wherein the sealing head has a base section, a front section and an intermediate section positioned between the base section and the front section, wherein the base section has a diameter greater than that of the front section and the intermediate section and has edges tapering downwards, wherein the intermediate section has a uniform outer diameter and the front section tapers downwards from the intermediate section. [19] Procedure comprising the following: Providing a spring fork, wherein the spring fork comprises a fork leg, the fork leg comprising a shaft and a sealing head coupled to the shaft, and a reservoir that holds bath oil near the sealing head; and During compression of the fork leg, the sealing head causes the bath oil to be flung upwards to lubricate an upper component of the fork leg. [20] Method according to claim 19, wherein the upper component to be lubricated comprises: an upper tube of the fork leg and / or at least one upper bushing and / or a foam ring.

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