Multi-bar tailgate lift assist system

Abstract

A vehicle tailgate lift assist system comprises a driveshaft attachable to a tailgate for rotation therewith. A crank arm and linkage assembly operatively couple the driveshaft to an energy storage device that is at least partially installable within and anchorable at a first end to the vehicle's body. A body bracket is configured to rigidly couple to the vehicle's body and pivotally couple to the driveshaft. The linkage assembly operatively couples the crank arm to the energy storage device and comprises first and second links. The first link is coupled to the crank arm and to the second link which is further coupled to the energy storage device distal to its anchored end. Opening and closing rotation of the tailgate about a pivot axis results respectively in storage and release of potential energy by the energy storage device.

Description

MULTI-BAR TAILGATE LIFT ASSIST SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from United States Provisional Patent Application Number 63 / 690,171 filed on September 3, 2024, the contents being incorporated herein by reference.TECHNICAL FIELD

[0002] This disclosure relates to vehicle tailgate systems, and more particularly to vehicle tailgate lift assist systems.BACKGROUND

[0003] Pickup vehicles typically have tailgates that open downward to provide access to the cargo area. These tailgates are generally quite heavy and have two undesirable characteristics: (i) during closing, the force to lift the tailgate can be understandably high, and (ii) during opening, the tailgate can fall open quickly and slam against the stops in an uncontrolled manner. These characteristics can be mitigated with the introduction of a counterbalance and a damper. The counterbalance reduces the force required to lift and close the tailgate and the damper limits the opening speed of the tailgate.

[0004] Some known tailgate systems incorporate both a counterbalance and a damper using a specially configured gas strut. An example of such known tailgate systems is described in U.S. Patent No. 6,773,047 to Gruber. One disadvantage of such a system is the difficulty of fitting the hinge and strut in an area of the vehicle body that is crowded with significant reinforcements, such as the D-pillar of the vehicle’s cargo bed. This reinforcement is demanded by the construction of the vehicle, and the high forces experienced particularly during commercial use of such vehicles.SUMMARY

[0005] According to some embodiments, there is provided a vehicle tailgate lift assist system comprising a driveshaft, a crank arm, a body bracket, an energy storage device and a linkage assembly. The driveshaft is configured to operatively couple to a vehicle tailgate for rotation about a tailgate pivot axis. The crank arm is rigidly coupled to the drive shaft for rotation therewith about the tailgate pivot axis. The body bracket is configured to rigidly coupleto a vehicle body and pivotally couple to the driveshaft. The energy storage device is configured to be at least partially installed within the vehicle body and adapted to be pivotally anchored at a first end to the vehicle body. The linkage assembly is configured to operatively couple the crank arm to the energy storage device, the linkage assembly comprising at least a first link and a second link. The first link has a crank arm end pivotally connected to the crank arm and has a link connecting end pivotally connected to the second link between opposing ends of the second link. The second link has a body bracket end pivotally connected to the body bracket and an energy storage end pivotally connected to the energy storage device distally from the first end of the energy storage device. Rotation of the vehicle tailgate about the tailgate pivot axis in an opening direction results in storage of potential energy by the energy storage device up to a maximum when the vehicle tailgate reaches a fully open position and rotation of the vehicle tailgate in a closing direction results in the release of stored potential energy by the energy storage device.

[0006] According to some embodiments, the second link is longer than the first link.

[0007] According to some embodiments, the energy storage device comprises one or more of an elastomeric energy storage member, a spring, a pneumatic cylinder and a gas strut. According to some embodiments, the energy storage member comprises the spring and during the storage of potential energy the spring undergoes linear compression. According to some embodiments, the pneumatic cylinder or the gas strut is configured to provide a damping function.

[0008] According to some embodiments, the driveshaft comprises, at a first driveshaft end, a drive head shaped to interface and engage with a corresponding feature of a tailgate hinge that is configured to couple to the vehicle tailgate and, at a second driveshaft end distal to the first driveshaft end, a torque transfer member coupled to the crank arm. According to some embodiments, the drive head comprises a portion that is overmolded onto the drive shaft. According to some embodiments, the overmolding is formed of a thermoplastic or similar synthetic material.

[0009] According to some embodiments, the tailgate pivot axis runs through the drive head and the torque transfer member when the drive head is engaged with the corresponding feature of the tailgate hinge.

[0010] According to some embodiments, the corresponding feature of the tailgate hinge comprises a drive cup.

[0011] According to some embodiments, the system further comprises at least one bushing inserted into the body bracket or overmolded onto the body bracket to facilitate rotational movement of the drive shaft about the tailgate pivot axis. According to some embodiments, the bushing is formed of a thermoplastic or similar synthetic material.

[0012] According to some embodiments, the system further comprises a releasable coupling assembly configured to releasably couple the vehicle tailgate to the vehicle body at a location laterally distal to the drive shaft, the crank arm, the linkage assembly and the energy storage device. The location of the releasable coupling assembly is along the tailgate pivot axis.

[0013] According to some embodiments, the releasable coupling assembly comprises a pivotal support configured to couple to the vehicle body and a support cup configured to couple to the vehicle tailgate. The support cup is configured to receive the pivotal support and the pivotal support is configured to enable relative rotation of the support cup about the tailgate pivot axis. The support cup comprises a slot configured to allow the pivotal support to pass therethrough.

[0014] Further aspects of the claimed subject matter will be apparent from the following description and explanations.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a better understanding of the various embodiments described herein and to show more clearly how they may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0016] FIGS. 1 A and IB depict an example vehicle having a tailgate known in the art;

[0017] FIGS. 2A and 2B depict a vehicle tailgate lift assist system with a tailgate in a tailgate closed position (FIG. 2A) and a tailgate fully open position (FIG. 2B), according to non-limiting embodiments;

[0018] FIGS. 3A to 3D depict the vehicle tailgate lift assist system of FIGS. 2A and 2B, in tailgate open and closed positions, according to non-limiting embodiments;

[0019] FIG. 4 depicts an exploded view of the vehicle tailgate lift assist system of FIGS. 2A and 2B, according to non-limiting embodiments;

[0020] FIG. 5 A depicts an isolated front isometric view of the vehicle tailgate lift assist system of FIGS. 2A and 2B, absent the energy storage device, according to non-limiting embodiments;

[0021] FIG. 5B depicts a rear isometric view the vehicle tailgate lift assist system of FIG. 5B;

[0022] FIG. 6 depicts a section view of a driveshaft of the vehicle tailgate lift assist system of FIGS. 2A and 2B, according to non-limiting embodiments;

[0023] FIG. 7 depicts an enlarged front view of components of a vehicle tailgate lift assist system, according to non-limiting embodiments;

[0024] FIG. 8 depicts an enlarged side view of components of a vehicle tailgate lift assist system, according to non-limiting embodiments;

[0025] FIG. 9A depicts a vehicle tailgate lift assist system as installed on a vehicle, according to the prior art;

[0026] FIG. 9B depicts a vehicle tailgate lift assist system installed on a vehicle, according to non-limiting embodiments;

[0027] FIG. 10A depicts a releasable coupling assembly of a vehicle tailgate lift assist system, according to non-limiting embodiments; and

[0028] FIG. 10B depicts an exploded view of the releasable coupling assembly of a vehicle tailgate lift assist system of FIG. 10A.

[0029] The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.DETAILED DESCRIPTION

[0030] We have discovered an improved tailgate lift assist system that, at least according to some embodiments, fits within a more confined design envelope than known tailgate lift assist systems. The desired counterbalance and damping can be achieved in an otherwise restrictive package space. As a result, more freedom can be afforded to the positioning of the hinge components and the gas strut or other energy storage devices.

[0031] It will be appreciated that numerous specific details are set forth in order to provide a thorough understanding of the exemplary aspects of the present application described herein. However, it will be understood by those of ordinary skill in the art that the exemplary aspects described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the exemplary aspects described herein. Also, the description is not to be considered as limiting the scope of the exemplary aspects described herein. Any systems, method steps, method blocks, components, parts of components, and the like described herein in the singular are to be interpreted as also including a description of such systems, method steps or tasks, components, parts of components, and the like in the plural, and vice versa. Further aspects of the invention will be apparent from the attached images and explanations. The particular arrangement of the elements described herein may be modified as will be apparent to those skilled in the art.

[0032] In known tailgate lift assist systems, such as tailgate lift assist system 1 depicted in FIG. 9A, a single crank arm 3 operates between the tailgate hinge centreline 5 and the energy storage device connection 7. The possible pivot locations for the crank arm 3 and energy storage device 9 (e.g., a gas strut) are restrictive because the distance and angle of the strut relative to the crank arm 3 determines the effectiveness of the system. It can be difficult to find a design that is compatible with the surrounding structure, particularly with the main crossmember 11 of the vehicle body 17 (FIGS. 1 A, IB) that extends laterally between the left and right rear comers of the vehicle 15.

[0033] In the described improved tailgate lift assist systems, extra linkages are employed to give design freedom for the crank arm and the energy storage device locations. With the extra links, the energy storage device can be positioned further away from the hinge centreline, and it can be oriented in such a way that it both at least partially fits in the vehicle and provides the necessary counterbalance throughout the closing motion of the tailgate. The hinge components can be positioned to avoid nearby vehicle structures, such as main cross member 11 (FIG. 9B), and the kinematics can be optimized to ensure the customer expectations can be met.

[0034] In operation, according to some embodiments, when the described vehicle tailgate is closed (and possibly also latched), the tailgate hinge is in the closed position and the energy storage device is extended or minimum potential energy position. According to someembodiments, as the tailgate is opened, the crank arm rotates, pushing on the first, middle link, which causes the second, main link to rotate and the energy storage device to compress / retract or to store potential energy. This rotation is resisted by the force of the energy storage device and the opening speed is limited by the damping of the energy storage device as it compresses if the energy storage device is a gas strut, pneumatic cylinder or other mechanically similar device. When the tailgate is fully open and resting on the cable stays, the first tailgate hinge is in the open position and the energy storage device may be compressed or in the maximum potential energy position. As the tailgate is closed, the force from the energy storage device pushes on the first, main link, which pushes on the second, middle link, which in turn pushes on the crank arm. This force from the energy storage device counteracts at least some of the weight of the tailgate and the force required by the user to operate the tailgate in the closing direction is reduced.

[0035] Attention is directed to FIGS. 2A to 5B, which depict a vehicle tailgate lift assist system 100 and components thereof, according to non-limiting embodiments. Vehicle tailgate lift assist system 100 comprises driveshaft 102, crank arm 104, body bracket 106, energy storage device 108 and linkage assembly 110. Driveshaft 102 is configured to operatively couple to a vehicle tailgate, such as tailgate 13, for rotation about a tailgate pivot axis, P. For example, according to some embodiments, drive shaft 102 is configured to fixedly couple with a vehicle tailgate 13 via tailgate bracket 112, which rotates about tailgate pivot axis, P, when the tailgate 13 is moved between the fully open (FIG. 2B) and closed (FIG. 2A) positions. Crank arm 104 is rigidly coupled to driveshaft 102 for rotation therewith about tailgate pivot axis, P. Body bracket 106 is configured to rigidly couple to a vehicle body, such as vehicle body 17 of vehicle 15, and driveshaft 102. As a result, rotation of the vehicle tailgate 13 about pivot axis, P, during opening and closing of the vehicle tailgate 13 compels rotation of driveshaft 102 therewith relative to the fixed position of body bracket 106.

[0036] Energy storage device 108 is configured to be at least partially installed within vehicle body 17 and is adapted to be pivotally anchored at a first end 114 to vehicle body 17. For example, according to some embodiments, energy storage device 108 may be coupled to a body pillar 19 (FIG. 2B). Any suitable energy storage device or combination of energy storage devices is contemplated for energy storage device 108. For example, according to some embodiments, energy storage device 108 comprises one or more of an elastomeric energy storage member, a spring, a pneumatic cylinder and a gas strut.

[0037] Linkage assembly 110 is configured to operatively couple crank arm 104 to energy storage device 108. Linkage assembly 110 comprises at least a first link 116 and a second link 118. First link 116 has a crank arm end 120 pivotally connected to the crank arm 104 and a link connecting end 122 pivotally connected to second link 118 between opposing ends (for example, ends 124, 126) of second link 118 (FIGS. 5 A, 5B). Second link 118 comprises body bracket end 124 pivotally connected to the body bracket 106 and an energy storage end 126 that is pivotally connected to the energy storage device 108 distally from the first end 114 of energy storage device 108. Any suitable configuration of linkage assembly 110 is contemplated. For example, according to some embodiments, second link 118 is longer than first link 116.

[0038] In operation, rotation of the vehicle tailgate 13 about the pivot axis, P, in an opening direction, OD, results in the storage of potential energy by energy storage device 108 up to a maximum when the vehicle tailgate reaches a fully open position (FIG. 3D). Rotation of the vehicle tailgate 13 in a closing direction, CD, (opposite the opening direction) results in the release of stored potential energy by the energy storage device 108 (up to and until, for example, the vehicle tailgate reaches the closed position, shown in FIGS. 3A to3C). For example, according to some embodiments, the energy storage device 108 is a gas strut or a pneumatic cylinder. As shown in FIGS. 2A and 2B, opening the tailgate 13 results in retraction of the gas strut’s rod and the attached piston into the strut cylinder. During this retraction, the energy storage device 108 stores potential energy up to a maximum amount reached when the tailgate 13 is in the fully open position (FIG. 2B). The release of this potential energy during the closing of tailgate 13 helps to reduce the force it takes to lift the tailgate 13 from the open position to return to the closed position (FIG. 2A). In other words, the storage and release of potential energy in the manner described can provide a user with at least some assistance in lifting the vehicle’s tailgate, which is typically quite heavy. Furthermore, when the energy storage device 108 is a gas strut or another pneumatic device, energy storage device 108 may be specifically configured to provide damping in that the act of storing potential energy helps to provide at least some damping. In particular, during opening the piston inside the strut or pneumatic device passes through liquid or gaseous fluid, providing at least some resistance. Typically, the faster the tailgate falls to the open position the higher the resistance provided.

[0039] As noted above, energy storage device 108 may take a variety of forms. For example, according to some embodiments, energy storage device 108 comprises a spring, suchas a coil spring, and during the storage of potential energy (when the tailgate 13 is being opened) the spring undergoes linear compression. Likewise, during the release of stored potential energy (when the tailgate 13 is being closed) the spring undergoes linear extension, assisting in the lifting of the tailgate. In this example, the spring is unable to provide any damping during opening. However, according to some embodiments, the energy storage device 108 may comprise a plurality of energy storage devices where at least one is configured to provide damping or other resistive force during the opening of tailgate 13. Other suitable configurations of energy storage device 108 are contemplated. For example, according to some embodiments, energy storage device 108 comprises a spring configured to undergo linear compression during the release of stored potential energy and undergoes linear extension during the storage of potential energy.

[0040] Vehicle tailgate lift assist system 100 may comprise certain vehicle tarigate / vehicle / lift assist system interface features. For example, according to some embodiments, driveshaft 102 comprises, at a first driveshaft end 128, a drive head 130 shaped to interface and engage with a corresponding feature 132 of tailgate bracket 112 and, at a second driveshaft end 134 distal first driveshaft end 128, there is atorque transfer member 136 coupled to the crank arm 104 (FIGS. 6 to 8). On the tailgate bracket 112 side, the corresponding feature 132 may comprise a drive cup (FIG. 4) configured to receive and engage drive head 130 such that rotation of tailgate bracket 112 with tailgate 13 results in similar rotation of drive head 130 (with driveshaft 102). In other words, drive head 130 may be shaped and sized to closely fit into corresponding feature 132 to couple rotation of the driveshaft 102 with tailgate 13. More specifically, according to some embodiments, the tailgate pivot axis, P, runs through drive head 130 and torque transfer member 136 when drive head 130 is engaged with corresponding feature 132 of tailgate bracket 112 (see, for example, FIG. 4). However, according to some embodiments, corresponding feature 132 is configured to provide some rotational slippage before driveshaft 102 rotates with tailgate 13 (e.g., corresponding feature 132 may be sized and shaped accordingly). For example, corresponding feature 132 and drive head 130 may be configured similarly to the male slot drive feature and the female slot drive feature, respectively, described in U.S. Patent No. 6,773,047 to Gruber, the contents of which are herein incorporated by reference. According to some embodiments, the relative rotational slippage between corresponding feature 132 and drive head 130 before rotationally engagingtherewith is about 15 degrees in one or more of the opening direction (OD) and the closing direction (CD).

[0041] According to some embodiments, drive head 130 may comprise a portion 138 that is overmolded onto driveshaft 102 (FIG. 6). Any suitable material or combination of materials for the overmolded portion 138 is contemplated. According to some embodiments, the overmolded portion 138 is formed of a thermoplastic, carbon fibre or similar synthetic material. For example, according to some embodiments, the overmolded portion is formed out of reinforced nylon.

[0042] As noted above, rotation of crank arm 104 about tailgate pivot axis, P, results from rotation of tailgate 13 during opening and closing. Torque transfer member 136 is configured to improve transmission of such rotation (torque) from the tailgate 13 via driveshaft 102 to crank arm 104. According to some embodiments, as shown in FIGS. 6 to 8, torque transfer member 136 may be formed as a projection of driveshaft 102 configured to mechanically engage crank arm 104. Any suitable means of manufacturing torque transfer member 136 is contemplated. For example, torque transfer member 136 may be formed by riveting or staking the second driveshaft end 134 firmly against the crank arm 104.

[0043] To facilitate rotational movement of driveshaft 102 about tailgate pivot axis, P, vehicle tailgate lift assist system 100 may comprise at least one bushing, such as bushings 140, inserted into body bracket 106 or overmolded onto body bracket 106 (FIG. 6). Any suitable material or combination of materials for bushings 140 is contemplated. For example, according to some embodiments, bushings 140 are formed from a thermoplastic or similar synthetic material. For example, according to some embodiments, bushings 140 are formed from polytetrafluoroethylene (PTFE).

[0044] According to some embodiments, the coupling between drive head 130 and corresponding feature 132 is releasable for easy removal of tailgate 13 (which may be desired for maintenance purposes). For example, as shown in FIGS. 6 to 8, drive head 130 may be sized and shaped to complement and fit with or into corresponding feature 132 (depicted as a drive cup) without being permanently attached. As such, removal of the tailgate 13 from the vehicle tailgate assist system 100 (and vehicle 15) can be facilitated.

[0045] According to some embodiments, vehicle tailgate lift assist system 100 comprises additional features to facilitate support and removal of the tailgate 13 from vehicle 15. For example, according to some embodiments, vehicle tailgate lift assist system 100comprises a releasable coupling assembly 142 (FIGS. 10A and 10B) configured to releasably couple vehicle tailgate 13 to vehicle body 15 at a location laterally distal to driveshaft 102, crank arm 104, linkage assembly 110 and energy storage device 108. The location of the releasable coupling assembly 142 is located along tailgate pivot axis, P. This releasable coupling assembly 142 (also referred to herein as a second tailgate hinge assembly) works in conjunction with the described vehicle tailgate lift assist system 100 to also support the tailgate 13 and allow the tailgate 13 to open and close.

[0046] Releasable coupling assembly 142 may take a variety of forms. For example, according to some embodiments, releasable coupling assembly 142 comprises a pivotal support 144 and a cup 146 (FIGS. 10A and 10B). Pivotal support 144 is configured to couple to vehicle body 17, such as by way of a secondary body bracket 148 that is configured to couple to vehicle body 17. Pivotal support 144, also referred to herein as post 144, is configured to enable relative rotation of support cup 146 about tailgate pivot axis, P. Support cup 146 is configured to couple to tailgate 13, such as by way of secondary tailgate bracket 150 that is configured to fixedly couple to tailgate 13. Support cup 146 is configured to receive pivotal support 144 therein and comprises a slot 152 (FIG. 10B) configured to allow pivotal support 144 to pass therethrough when at a certain relative orientation or relative pivotal position to slot 152. For example, in operation, tailgate 13 may be removed from vehicle body 17 when opened to a certain angular position, enabling the tailgate 13 to be lifted away from vehicle body 17 when pivotal support 144 reaches a predetermined orientation (pivot angle) relative to support cup 146.

[0047] Any suitable configurations of pivotal support 144 and support cup 146 are contemplated. For example, as shown in FIGS. 10A and 10B, pivotal support 144 may be sized and shaped to fit into support cup 146 and to pass through slot 152 when tailgate 13 is being removed from vehicle body 17. Pivotal support 144 may be circular with flats on either side, sized, shaped and positioned at an angle for suitable removal of tailgate 13. Support cup 146 may be circular in shape; however, any suitable shape complementary to pivotal support 144 is contemplated. Slot 152 comprises any opening sized and shaped to allow pivotal support 144 to pass therethrough. For example, in operation, tailgate 13 may be removed when opened to the predetermined orientation and slot 152 aligns with flat sections or otherwise complementarily shaped portions of pivotal support 144. A user is then able to lift tailgate 13 on the side having the releasable coupling assembly 142 away from vehicle body 17 and thenslide or otherwise release the opposite side of tailgate 13 out of its coupling with driveshaft 102 from tailgate bracket 112.

[0048] It will also be understood that for the purposes of this application, "at least one of X, Y, and Z" or "one or more of X, Y, and Z" language can be construed as X only, Y only, Z only, or any combination of two or more items X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ, XX, XY).

[0049] In the present application, components may be described as being "configured to" or "enabled to" perform one or more functions. Generally, it is understood that a component that is configured to or enabled to perform a function is configured to or enabled to perform the function, or is suitable for performing the function, or is adapted to perform the function, or is operable to perform the function, or is otherwise capable of performing the function.

[0050] Additionally, components in the present application may be described as being "operatively connected to", "operatively coupled to", and the like, to other components. It is understood that such components are connected or coupled to each other in a manner to perform a certain function. It is also understood that "connections", "coupling" and the like, as recited in the present application include direct and indirect connections between components.

[0051] References in the application to "one embodiment", "an embodiment", "an implementation", "a variant", etc., indicate that the embodiment, implementation or variant described may include a particular aspect, feature, structure, or characteristic, but not every embodiment, implementation or variant necessarily includes that aspect, feature, structure, or characteristic. Moreover, such phrases may, but do not necessarily, refer to the same embodiment referred to in other portions of the specification. Further, when a particular aspect, feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of one skilled in the art to affect or connect such module, aspect, feature, structure, or characteristic with other embodiments, whether or not explicitly described. In other words, any module, element or feature may be combined with any other element or feature in different embodiments, unless there is an obvious or inherent incompatibility, or it is specifically excluded.

[0052] It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for the use of exclusive terminology, such as "solely", "only", and the like, in connection with the recitation of claimelements or use of a "negative" limitation. The terms "preferably", "preferred", "prefer", "optionally", "may", and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.

[0053] The singular forms "a", "an", and "the" include the plural reference unless the context clearly dictates otherwise. The term "and / or" means any one of the items, any combination of the items, or all of the items with which this term is associated. The phrase "one or more" is readily understood by one of skill in the art, particularly when read in context of its usage.

[0054] The term "about" can refer to a variation of± 5%, ± 10%, ± 20%, or± 25% of the value specified. For example, "about 50" percent can in some embodiments carry a variation from 45 to 55 percent. For integer ranges, the term "about" can include one or two integers greater than and / or less than a recited integer at each end of the range. Unless indicated otherwise herein, the term "about" is intended to include values and ranges proximate to the recited range that are equivalent in terms of the functionality of the composition, or the embodiment.

[0055] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges recited herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof, as well as the individual values making up the range, particularly integer values. A recited range includes each specific value, integer, decimal, or identity within the range. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, or tenths. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc.

[0056] As will also be understood by one skilled in the art, all language such as "up to", "at least", "greater than", "less than", "more than", "or more", and the like, include the number recited and such terms refer to ranges that can be subsequently broken down into subranges as discussed above. In the same manner, all ratios recited herein also include all subratios falling within the broader ratio.

[0057] Persons skilled in the art will appreciate that there are yet more alternative implementations and modifications possible, and that the above examples are only illustrationsof one or more implementations. The scope, therefore, is only to be limited by the claims appended hereto.

Claims

CLAIMS1. A vehicle tailgate lift assist system comprising: a driveshaft configured to operatively couple to a vehicle tailgate for rotation about a tailgate pivot axis; a crank arm rigidly coupled to the driveshaft for rotation therewith about the tailgate pivot axis; a body bracket configured to rigidly couple to a vehicle body and pivotally couple to the driveshaft; an energy storage device configured to be at least partially installed within the vehicle body and adapted to be pivotally anchored at a first end to the vehicle body; and a linkage assembly configured to operatively couple the crank arm to the energy storage device, the linkage assembly comprising at least a first link and a second link; wherein: the first link has a crank arm end pivotally connected to the crank arm and has a link connecting end pivotally connected to the second link between opposing ends of the second link; the second link having a body bracket end pivotally connected to the body bracket and an energy storage end pivotally connected to the energy storage device distally from the first end of the energy storage device; and rotation of the vehicle tailgate about the tailgate pivot axis in an opening direction results in storage of potential energy by the energy storage device up to a maximum when the vehicle tailgate reaches a fully open position and rotation of the vehicle tailgate in a closing direction results in the release of stored potential energy by the energy storage device.

2. The vehicle tailgate lift assist system of claim 1, wherein the second link is longer than the first link.

3. The vehicle tailgate lift assist system of either claim 1 or claim 2, wherein the energy storage device comprises one or more of an elastomeric energy storage member, a spring, a pneumatic cylinder and a gas strut.

4. The vehicle tailgate lift assist system of claim 3, wherein the energy storage member comprises the spring and during the storage of potential energy the spring undergoes linear compression.

5. The vehicle tailgate lift assist system of claim 3, wherein the pneumatic cylinder or the gas strut is configured to provide a damping function.

6. The vehicle tailgate lift assist system of any one of claims 1 to 5, wherein the driveshaft comprises, at a first driveshaft end, a drive head shaped to interface and engage with a corresponding feature of a tailgate hinge configured to couple to the vehicle tailgate and, at a second driveshaft end distal to the first driveshaft end, a torque transfer member coupled to the crank arm.

7. The vehicle tailgate lift assist system of claim 6, wherein the drive head comprises a portion that is overmolded onto the drive shaft.

8. The vehicle tailgate lift assist system of claim 7, wherein the overmolding is formed of a thermoplastic or similar synthetic material.

9. The vehicle tailgate lift assist system of any one of claims 6 to 8, wherein the tailgate pivot axis runs through the drive head and the torque transfer member when the drive head is engaged with the corresponding feature of the tailgate hinge.

10. The vehicle tailgate lift assist system of any one of claims 6 to 9, wherein the corresponding feature of the tailgate hinge comprises a drive cup.

11. The vehicle tailgate lift assist system of any one of claims 1 to 10, further comprising at least one bushing inserted into the body bracket or overmolded onto the body bracket to facilitate rotational movement of the drive shaft about the tailgate pivot axis.

12. The vehicle tailgate lift assist system of claim 11, wherein the bushing is formed of a thermoplastic or similar synthetic material.

13. The vehicle tailgate lift assist system of any one of claims 1 to 12, further comprising a releasable coupling assembly configured to releasably couple the vehicle tailgate to thevehicle body at a location laterally distal to the drive shaft, the crank arm, the linkage assembly and the energy storage device, wherein the location is along the tailgate pivot axis.

14. The vehicle tailgate lift assist system of claim 13, wherein the releasable coupling assembly comprises a pivotal support configured to couple to the vehicle body and a support cup configured to couple to the vehicle tailgate; and wherein: the support cup is configured to receive the pivotal support; the pivotal support is configured to enable relative rotation of the support cup about the tailgate pivot axis; and the support cup comprises a slot configured to allow the pivotal support to pass therethrough.

Images