TECHNICAL FIELD

[0001] The present application relates to a fastener assembly and, more particularly, to a fastener assembly including a grommet.

BACKGROUND

[0002] A fastener assembly can be used to connect at least two components together in industrial applications. At least two components connected together also need to be disassembled in some applications. Therefore, a fastener assembly needs to meet the requirements for fastening and connection and being easy to disassemble.

SUMMARY

[0003] The grommet and fastener assembly provided by the present application can at least partly solve the above-mentioned technical problem. In a first aspect, the present application provides a grommet, the grommet having an axis and a channel extending along the axis, the grommet comprising: a body, the body comprising a wall, the wall comprising an inner surface; and a plurality of legs, the plurality of legs being arranged around the axis, each leg of the plurality of legs comprising a near end and a far end, said each leg being connected to the bottom of the body via its near end and roughly extending along the axis, said each leg moving towards or away from the axis around its near end, wherein said each leg has a first position where it is in a free state and a second position where it opens outwards with respect to the axis; the inner surface of the body and the legs jointly define and form the channel; the body further comprises a position- limiting protrusion, the position-limiting protrusion being formed by protruding from the inner surface of the body towards the axis.

[0004] According to the above-mentioned first aspect, the position-limiting protrusion is provided at the bottom of the inner surface, the near end of said each leg being connected to the position-limiting protrusion.

[0005] According to the above-mentioned first aspect, the inner surface of said each leg and the inner surface of the position-limiting protrusion roughly continuously extend along the axis.

[0006] According to the above-mentioned first aspect, the position-limiting protrusion is set to extend around the axis. [0007] According to the above-mentioned first aspect, the body has a hollowed-out part, the hollowed-out part being formed by upward hollowing of the bottom of the wall of the body.

[0008] In a second aspect, the present application provides a fastener assembly, comprising: a grommet, the grommet having an axis and a channel extending along the axis, the grommet comprising: a body, the body comprising a wall, the wall comprising an inner surface; and a plurality of legs, the plurality of legs being arranged around the axis, each leg of the plurality of legs comprising a near end and a far end, the each leg being connected to the bottom of the body via its near end and roughly extending along the axis, said each leg moving towards or away from the axis around its near end, wherein said each leg has a first position where it is in a free state and a second position where it opens outwards with respect to the axis; the inner surface of the body and the legs jointly define and form the channel; the body further comprises a position-limiting protrusion, said position-limiting protrusion being formed by protruding from the inner surface of the body towards the axis; and a fastening pin, the fastening pin being able to move in the channel in the direction of the axis, the fastening pin comprising a head and a rod connected to the head, the outer diameter of the head being greater than the maximum outer diameter of the rod; the position-limiting protrusion of the body is configured to be able to press against the lower surface of the head of the fastening pin to limit any continued downward movement of the fastening pin with respect to the grommet.

[0009] According to the above-mentioned second aspect, the position-limiting protrusion is provided at the bottom of the inner surface, the near end of the each leg being connected to the position-limiting protrusion; the inner surface of the each leg and the inner surface of the position- limiting protrusion roughly continuously extend along the axis.

[0010] According to the above-mentioned second aspect, the position-limiting protrusion is set to extend around the axis.

[0011] According to the above-mentioned second aspect, the body has a hollowed-out part, the hollowed-out part being formed by upward hollowing of the bottom of the wall of the body.

[0012] According to the above-mentioned second aspect, the body has a height along the axis, the height of the body being set so that the height of the channel above the position-limiting protrusion satisfies the movement distance of the fastening pin. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figs. 1A and IB are respectively 3D structural views of a fastener assembly according to the present application from two view angles.

[0014] Fig. 1C is an exploded view of the fastener assembly shown in Fig. 1A.

[0015] Fig. ID is a front view of the fastener assembly shown in Fig. 1A.

[0016] Fig. IE is a side view of the fastener assembly shown in Fig. 1A.

[0017] Fig. 2A is a 3D structural view of a grommet shown in Fig. 1C.

[0018] Fig. 2B is a sectional view of the grommet shown in Fig. 2A along the A-A line shown in Fig. ID.

[0019] Fig. 2C is a sectional view of the grommet shown in Fig. 2 A along the B-B line shown in Fig. IE.

[0020] Fig. 3A is a 3D structural view of a fastening pin shown in Fig. 1C.

[0021] Fig. 3B is a sectional view of a fastening pin shown in Fig. 3A along the A-A line shown in Fig. ID.

[0022] Figs. 4A-4C are sectional views of coupling states between the fastener assembly and two plates. The fastener assembly shown in Figs. 4 A, 4B and 4C is in the pre-installation state, fastening state and release state, respectively.

DETAIFED DESCRIPTION

[0023] Various embodiments of the present application will be described below by referring to the accompanying drawings which are a part of the description. It should be understood that although directional terms such as "front", "rear", "upper", "lower", "left", "right", "top", "bottom", "inner" and "outer" are used to describe structural parts and elements of various examples in the present application, their use here is solely for the purpose of description and is determined based on the example directions shown in the accompanying drawings. Because the embodiments disclosed in the present application can be set in different directions, these directional terms are only descriptive and should not be deemed as limitations. [0024] Figs. 1A-1E are structural views of a fastener assembly 100 according to the present application, showing an approximate structure of the fastener assembly 100. Figs. 1A and IB are respectively 3D structural views of a fastener assembly 100 from the top and bottom view angles. Fig. 1C is an exploded view of the fastener assembly 100. Fig. ID is a front view of the fastener assembly 100 shown in Fig. 1A. Fig. IE is a side view of the fastener assembly 100 shown in Fig. 1A.

[0025] As shown in Figs. 1A-1E, the fastener assembly 100 comprises a grommet 120 and a fastening pin 110. The grommet 120 is hollow and has a channel 130 that runs through the grommet and extends along the axis x. The fastening pin 110 is provided in the channel 130 and is able to move in the channel 130 in the direction of the axis x. The fastener assembly 100 may be in a pre installation state, a fastening state and a release state, depending on the movement of the fastening pin 110 to different positions in the channel 130. In the pre-installation state, the fastener assembly 100 is pre-installed to at least two components to be connected. In the fastening state, the fastener assembly 100 fastens and connects at least two components. In the release state, the fastener assembly 100 is disassembled from at least two connected components.

[0026] The grommet 120 comprises a body 113 and a plurality of legs 121 connected to the bottom of the body 113. The body 113 is roughly of a hollow cylindrical shape and comprises a wall 125, the wall 125 having an inner surface 127. The inner surface 127 of the body 113 and said each leg 121 jointly define and form the channel 130. In this embodiment, the body 113 has a hollowed-out part 123, the hollowed-out part 123 being formed by upward hollowing of the bottom of the wall 125 of the body 113 so that the wall 125 comprises an outer side wall 161, an inner side wall 162 and a top wall 163, the top wall 163 being connected between the tops of the outer side wall 161 and the inner side wall 162. The inner surface 127 is provided on the inner side wall 162.

[0027] The plurality of legs 121 are arranged around the axis x. In this embodiment, the plurality of legs 121 are four legs 121 that are uniformly arranged around the axis x. Said each leg 121 roughly extends from the bottom of the body 113 along the axis x and the outer surfaces of the legs 121 roughly extend in parallel with the axis x so that the outer surfaces of the four legs 121 form a cylindrical shape around the axis x. There is a gap 133 circumferentially between adjacent legs 121. Specifically, said each leg 121 comprises a near end 131 and a far end 132 opposite to the near end 131, the near end 131 being connected to the bottom of the body 113, the far end 132 being a free end. Therefore, said each leg 121 can be deformed to move towards or away from the axis x around the respective near end 131. In the state shown in Figs. 1A-1E, the legs 121 are in the free state and have a first position. When an outward force is applied from inside to the legs 121, the legs 121 move away from the axis x outwards until they reach the opening state where they have a second position. When this outward force is released, the legs 121 move towards the axis x inwards back to the first position.

[0028] The fastening pin 110 comprises a head 111 and a rod 115. The head 111 is connected to the top of the rod 115 and the outer diameter of the head 111 is greater than the maximum outer diameter of the rod 115. The head 111 is roughly of a thin circular sheet shape with a certain thickness. The rod 115 is roughly of a rod shape and comprises a plurality of segments with different thicknesses in the direction of the axis x. When the fastening pin 110 moves in the channel 130 with respect to the grommet 120, the legs 121 can move to the first or second position and the fastener assembly 100 can be in the pre-installation state, fastening state and release state via the coupling between the legs 121 of the grommet 120 and the different segments of the rod 115.

[0029] The fastening pin 110 further comprises a plurality of longitudinal ribs 116. The longitudinal ribs 116 extend from the top end to the bottom end of the rod 115 in the direction of the axis x. When the fastening pin 110 moves in the channel 130, the longitudinal ribs 116 are configured so that the fastening pin 110 cannot rotate around the axis x. In this embodiment, the number of longitudinal ribs 116 is set to four.

[0030] Figs. 2A-2C show a specific structure of the grommet 120. Fig. 2A is a 3D structural view of the grommet 120. Fig. 2B is a sectional view of the grommet 120 shown in Fig. 2A along the A- A section line shown in Fig. ID. Fig. 2C is a sectional view of the grommet 120 shown in Fig. 2 A along the B-B section line shown in Fig. IE. As shown in Figs. 2A-2C, the body 113 of the grommet 120 further comprises a position-limiting protrusion 118, the position-limiting protrusion 118 being formed by protruding from the lower part of the inner surface 127 towards the axis x. The top of the position-limiting protrusion 118 is used to press against the lower surface of the head 111 of the fastening pin 110 to limit a limit position of the fastening pin 110 during downward movement. The bottom of the position- limiting protrusion 118 is connected to the near end 131 of the legs 121. It should be understood by those skilled in the art that in other embodiments, the legs 121 can also be connected to other positions at the bottom of the body 113 or set to other quantities.

[0031] To meet the requirements for the movement distance of the fastening pin 110, the body 113 has a certain height in the direction of the axis x and there is a certain distance between the top of the position-limiting protrusion 118 and the top of the body 113, which will be described by referring to Figs. 3 A and 3B.

[0032] In this embodiment, the position-limiting protrusion 118 is a ring around the axis x, a plurality of, for example four, grooves 165 are provided at intervals on the position-limiting protrusion 118, and each groove 165 is formed by the hollowing of the inner surface of the position-limiting protrusion 118 in the direction away from the axis x. The grooves 165 are connected to a corresponding gap 133. The grooves 165 and the gaps 133 are used to fit with the longitudinal ribs 116 of the fastening pin 110 to contain the longitudinal ribs 116 in the grooves 165 and the gaps 133. Furthermore, in this embodiment, the inner surface of the legs 121 and the inner surface of the position-limiting protrusion 118 continuously extend roughly in the direction of the axis x. That is, each leg 121 is formed by downward extending of the bottom of the position- limiting protrusion 118, as shown by the sectional view in Fig. 2B. Moreover, the inner surface of the near end 131 of the legs 121 is roughly flush with the inner surface of the position-limiting protrusion 118 and continuously extends. The thickness formed between the inner and outer surfaces of the near end 131 of the legs 121 is slightly smaller than that of other parts of the legs 121 below the near end 131 so that the legs 121 are deformed using the near end 131 as a point of rotation.

[0033] The far end 132 of each leg 121 comprises a claw 228. The claw 228 is formed by protruding from the inner surface of the far end 132 towards the axis x to form a roughly hook shaped claw 228. The claw 228 fits with each segment of different rod diameters for the rod 115 of the fastening pin 110 so that the legs 121 can move towards or away from the axis x around the near end 131.

[0034] Figs. 3A and 3B show a specific structure of the fastening pin. Fig. 3A is a 3D structural view of the fastening pin 110. Fig. 3B is a sectional view of the fastening pin 110 along the A-A line shown in Fig. ID. As shown in Figs. 3A and 3B, the rod 115 of the fastening pin 110 comprises a first thin rod diameter segment 342, a first thick rod diameter segment 343 and a second thin rod diameter segment 346 roughly located in the middle and lower parts and successively arranged from top to bottom in the direction of the axis x. The cross-sectional dimension of the first thick rod diameter segment 343 is greater than that of the first thin rod diameter segment 342 and that of the second thin rod diameter segment 346. As a specific example, the first thin rod diameter segment 342 is formed by inward hollowing of the outer surface of the rod 115 above the first thick rod diameter segment 343 and the second thin rod diameter segment 346 is formed by inward hollowing of the outer surface of the rod 115 below the first thick rod diameter segment 343.

[0035] The fastening pin 110 is inserted downwards into the channel 130 of the grommet 120, and when the claw 228 of the legs 121 presses against the outer side of the second thin rod diameter segment 346 (refer to the pre-installation state of the fastener assembly 100 shown in Fig. 4A), the legs 121 are located in the first position; the fastening pin 110 continues to move down, and when the claw 228 of the legs 121 presses against the first thick rod diameter segment 343 (refer to the fastening state of the fastener assembly 100 shown in Fig. 4B), the legs 121 are unfolded to the second position; the pin 110 continues to move down, and when the claw 228 of the legs 121 presses against the first thin rod diameter segment 342 (refer to the release state of the fastener assembly 100 shown in Fig. 4C), the legs 121 go back to the first position. Therefore, the legs 121 of the grommet 120 can move to the first or second position using different rod diameter segments of the rod 115 of the fastening pin 110.

[0036] In this embodiment, the heights of the grommet 120 and the fastening pin 110 in the direction of the axis x are set so that when the fastening pin 110 moves until the fastener assembly 100 is in the fastening state, the claw 228 of the legs 121 presses against the first thick rod diameter segment 343 and the upper surface of the head 111 of the fastening pin 110 is roughly flush with the upper surface of the top wall 163 of the body 113 of the grommet 120; when the fastening pin 110 moves until the fastener assembly 100 is in the release state, the claw 228 of the legs 121 presses against the first thin rod diameter segment 342 and the lower surface of the head 111 of the fastening pin 110 presses against the upper surface of the position-limiting protrusion 118. That is, when the fastener assembly 100 moves from the fastening state to the release state, the movement distance of the fastening pin 110 is a distance between the first thick rod diameter segment 343 and first thin rod diameter segment 342 of the fastening pin 110. The distance between the top of the position-limiting protrusion 118 and the top of the body 113 matches this movement distance. [0037] Still as shown in Figs. 3A and 3B, the heights of the first thin rod diameter segment 342 and the second thin rod diameter segment 346 are set to match the height of the claw 228 of the legs 121 so that the claw 228 can be accommodated and stay in the first thin rod diameter segment 342 or second thin rod diameter segment 346. In addition, grooves 335 that are slightly hollowed inwards are provided on the first thick rod diameter segment 343 so that the claw 228 can be accommodated and stay in the grooves 335. Therefore, the relative position between the fastening pin 110 and the grommet 120 can be maintained more stably.

[0038] The rod 115 further comprises a second thick rod diameter segment 341 above the first thin rod diameter segment 342. The first thin rod diameter segment 342 is connected between the second thick rod diameter segment 341 and the first thick rod diameter segment 343 using two conical segments. Furthermore, the second thin rod diameter segment 346 is connected to the first thick rod diameter segment 343 using a conical segment 345. Therefore, when the claw 228 is accommodated in the first thin rod diameter segment 342, first thick rod diameter segment 343 or second thin rod diameter segment 346 and an external force is applied to the fastening pin 110, the conical segments play a guide role to facilitate the movement of the fastening pin 110 with respect to the grommet 120.

[0039] The rod 115 further comprises a tail 336 below the second thin rod diameter segment 346. As an example, the tail 336 can be a conical segment that plays a guide role when the fastening pin 110 is inserted into the channel 130 of the grommet 120. Moreover, the second thin rod diameter segment 346 is connected to the tail 336 via a plane 337 to prevent the fastening pin 110 from moving upwards out of the channel 130 of the grommet 120 with respect to the grommet 120 when the claw 228 is accommodated in the second thin rod diameter segment 346.

[0040] Figs. 4A-4C show a structure of the fastener assembly 100 in the pre-installation state, fastening state and release state, respectively. Figs. 4A and 4B show the installation process of the fastener assembly 100. Figs. 4B and 4C show the disassembly process of the fastener assembly 100. As shown in Figs. 4A-4C, two components to be fastened respectively comprise an upper plate 471 and a lower plate 472. The upper plate 471 has a mounting hole 481 and the lower plate 472 has a mounting hole 482.

[0041] As shown in Fig. 4A, the fastener assembly 100 is in the pre-installation state. The body 113 of the grommet 120 presses against the upper surface of the upper plate 471 and said each leg 121 of the grommet 120 is inserted in the mounting hole 481 and the mounting hole 482. There is a small gap between the outer surface of the legs 121 and the edge of the mounting hole 481 and the mounting hole 482 to facilitate the insertion of the legs 121 of the grommet 120 into the mounting holes. The fastening pin 110 is located in the topmost limit position in the channel 130 of the grommet 120. The claw 228 of the legs 121 of the grommet 120 presses against the outer side of the second thin rod diameter segment 346 of the fastening pin 110 so that the legs 121 are located in the first position.

[0042] When a downward force F is applied to the fastening pin 110 in the pre-installation state shown in Fig. 4A, the grommet 120 of the fastener assembly 100 keeps pressing against the upper surface of the upper plate 471 without any movement. The fastening pin 110 of the fastener assembly 100 moves down the channel 130 with respect to the grommet 120. Because the fastening pin 110 moves down with respect to the grommet 120, the claw 228 of the legs 121 of the grommet 120 moves up to the outer side of the grooves 335 of the first thick rod diameter segment 343 from the outer side of the second thin rod diameter segment 346. An outward compressional force applied to the claw 228 of the legs 121 during the movement causes deformation at the near end 131 of the claw 228 and outward movement of the far end 132 in the direction away from the axis x so that the legs 121 move to the second position and the fastener assembly 100 reaches the fastening state shown in Fig. 4B.

[0043] As shown in Fig. 4B, the fastener assembly 100 is in the fastening state. The head 111 of the fastening pin 110 is roughly flush with the upper surface of the body 113. The claw 228 of the legs 121 of the grommet 120 presses against the outer side of the first thick rod diameter segment 343 of the fastening pin 110. The outer surface of the legs 121 presses the hole edge of the mounting hole 482 to clamp the upper plate 471 and the lower plate 472 between the body 113 and the outer surface of the legs 121 of the grommet 120, thus fastening and connecting the upper plate 471 and the lower plate 472. In this state, both the grommet 120 and the fastening pin 110 cannot move up and down if no external force is applied to the fastening pin 110.

[0044] When a downward force F continues to be applied to the fastening pin 110, the grommet 120 of the fastener assembly 100 keeps pressing against the upper surface of the upper plate 471 without any movement. The fastening pin 110 of the fastener assembly 100 continues to move down the channel 130 with respect to the grommet 120 until the head 111 of the fastening pin 110 moves down to press against the upper surface of the position-limiting protrusion 118 without any continued downward movement. In the process of downward movement of the fastening pin 110 with respect to the grommet 120, the claw 228 of the legs 121 of the grommet 120 moves up to press against the outer side of the first thin rod diameter segment 342 of the fastening pin 110 from the outer side of the grooves 335 of the first thick rod diameter segment 343 accordingly. An outward compressional force is no longer applied to the claw 228 of the legs 121 so that the legs 121 go back to the first position. The fastener assembly 100 reaches the release state shown in Fig. 4C. At this moment, the outer surface of the legs 121 no longer presses against the hole edge of the mounting hole 482. Operators can manually remove the fastener assembly 100 from the mounting hole from the upper side of the upper plate 471.

[0045] In the fastener assembly in the present application, the fastening and disassembling process of the fastener assembly can be finished by only applying a force to the fastening pin 110 from the upper side of the upper plate 471 without using other auxiliary tools, especially where the upper plate 471 and the lower plate 472 need to be fastened and connected in the case of insufficient space or inconvenient operation on the upper side of the upper plate 471.

[0046] In the prior art, the position-limiting protrusion is provided on the legs of the grommet. The inventors of the present application find that because the legs can be unfolded under a small force, when a force continues to be applied to the fastening pin after the fastening pin reaches the release position, the large-diameter head of the fastening pin will re-unfold the legs so that the fastener assembly will restore to the fastening state from the release state and the fastening pin may fall out of the opening below the channel into the inside of components to be fastened. Furthermore, if the position-limiting protrusion is provided on the legs of the grommet, it will cause the corresponding part of the legs to become thinner, thus resulting in less tension in the legs due to the limitation of external dimensions of the grommet and the fastening pin.

[0047] In the present application, a position-limiting protrusion is provided on the inner surface of the body of the grommet to limit any continued downward movement of the fastening pin when the fastening pin moves down until the fastener assembly reaches the release state. Compared with providing the position-limiting protrusion on the legs of the grommet, the grommet in the present application can avoid re-unfolding of the legs as it continues to receive a force applied to the fastening pin after the fastening pin has moved to the point where the fastener assembly reaches the release state, thus avoiding the restoring of the fastener assembly to the fastening state from the release state and preventing the fastening pin from falling out of the opening below the channel. In addition, because the position-limiting protrusion is not provided on the legs, the legs have a large thickness and thus an increased tension.

[0048] Although the present application is described by referring to particular embodiments shown in the accompanying drawings, it should be understood that the grommet and fastener assembly in the present application may take many different forms without deviating from the spirit, scope and background of the present application. Those of ordinary skill in the art should also realize that the structure in the embodiments disclosed in the present application can be changed by different methods, all of which should fall within the spirit and scope of the present application and claims.