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EP-4513042-B1 - SNAP FASTENING UNIT

EP4513042B1EP 4513042 B1EP4513042 B1EP 4513042B1EP-4513042-B1

Inventors

  • VITRY, FABRICE
  • XIANG, Wenguang

Dates

Publication Date
20260513
Application Date
20240812

Claims (15)

  1. A snap fastening unit for being fastened to one or more thin walls with through holes, comprising a housing (1) and at least one snap block (2), the housing (1) having a fastening support wall (11) and a head portion (12) extending away from the fastening support wall (11), the head portion (12) having a guide channel (121); the snap block (2) being restricted to slide directionally on the guide channel (121) of the head portion (12) and being interchangeable between a fastening position and a releasing position on the head portion (12); in the fastening position, a clamping head (21) of the snap block (2) protruding from the head portion (12) and engaging with the fastening support wall (11) to form a fastened state allowing the snap block (2) to be fastened to the one or more thin walls (1-1); in the releasing position, the clamping head (21) of the snap block (2) retracting into the head portion (12) to form a detachable state allowing the head portion (12) of the snap fastening unit to freely enter and exit the through hole in the thin wall (1-1); the snap block (2) comprising an elastic element (3) providing an elastic loading force that drives the snap block (2) to slide to the fastening position and maintains the snap block (2) in the fastening position, wherein the snap fastening unit further comprises an automatic locking device; the automatic locking device comprises a first locking member (41) arranged on the snap block (2) and moveable along with the snap block (2), and a second locking member (42) arranged on the head portion (12); when the snap block (2) slides to the releasing position, the first locking member (41) and the second locking member (42) automatically lock together to lock the snap block (2) on the head portion (12), and meanwhile the elastic element (3) completes energy storage; the automatic locking device further comprises a triggering component which drives the first locking member (41) to unlock from the second locking member (42) to release the snap block (2) from the releasing position, and the snap block (2) released at the releasing position is driven by the energy storage of the elastic element (3) to return to the fastening position.
  2. The snap fastening unit according to claim 1, wherein the triggering component is arranged on the snap block (2) and is moveable along with the snap block (2), the triggering component comprises a triggering member (43) movably arranged on the snap block (2), and a trigger end reset spring (44) for driving the triggering member (43) to move and reset, the triggering member (43) has a triggering end for operating the triggering component, the triggering end is capable of protruding from a front end surface (21a) of the clamping head (21) to be exposed on the front end surface (21a) under the driving of the trigger end reset spring (44), the triggering end has an upper triggering surface (431) and a lower avoidance drive surface (432), a vertex (Q) is formed between the upper triggering surface (431) and the lower avoidance drive surface (432), the upper triggering surface (431) and the lower avoidance drive surface (432) are arranged along a direction in which the head portion (12) is inserted into the through hole in the thin wall (1-1); during the process of inserting the head portion (12) into the through hole in the thin wall (1-1) and the process of removing the head portion (12) from the through hole in the thin wall (1-1), the upper triggering surface (431) and the lower avoidance drive surface (432) directly contact and abut a periphery of the through hole in the thin wall (1-1) to drive the triggering end to retract towards a rear side of the front end surface (21a) of the clamping head (21) of the snap block (2), and during the process of inserting the head portion (12) into the through hole in the thin wall (1-1), the upper triggering surface (431) directly contacts and abuts the periphery of the through hole in the thin wall (1-1) to operate the triggering component to unlock the first locking member (41) from the second locking member (42).
  3. The snap fastening unit according to claim 2, wherein the first locking member (41) comprises a movable lock piece (411) arranged on the snap block (2); the movable lock piece (411) comprises a lock spring (412), which provides a spring force to drive the movable lock piece (411) to engage and lock with the second locking member (42); the triggering component is operated to drive the movable lock piece (411) to act such that the movable lock piece (411) disengages with the second locking member (42).
  4. The snap fastening unit according to claim 3, wherein the second locking member (42) is a protrusion or a recess formed in an inner wall of the guide channel (121) of the head portion (12).
  5. The fastening unit according to claim 3, wherein the movable lock piece (411) is rotatably arranged on the snap block (2), and a locking portion (4111) on the movable lock piece (411) is offset from a rotation center of the movable lock piece (411).
  6. The snap fastening unit according to claim 5, wherein the locking portion (4111) is a hook-shaped hook head, and the second locking member (42) is a hooking structure allowing the hook head to hook thereon.
  7. The snap fastening unit according to claim 6, wherein the triggering member (43) is a lever arm fixed or integrally formed on the movable lock piece (411), the lever arm and the movable lock piece (411) forms a lever structure with a pivot point located between the lever arm and the hook head, the lock spring (412) simultaneously serves as the trigger end reset spring (44) for driving the lever arm to be in a non-triggered state, and the lower avoidance drive surface (432) is a convex arc-shaped surface.
  8. The snap fastening unit according to claim 7, wherein the lock spring (412) is a compression coil spring, one end of the compression coil spring abuts the snap block (2), and an other end of the compression coil spring abuts the lever arm, the lever arm is hook-shaped, and the compression coil spring is located in a hook opening of the lever arm.
  9. The snap fastening unit according to claim 5, wherein the triggering member (43) is slidably arranged on the snap block (2); a sliding direction of the triggering member (43) is the same as a sliding direction the snap block (2); one end of the triggering member (43) has the triggering end for operating the triggering component to be in a triggered state, and an other end of the triggering member (43) has a driving end (433); the locking portion (4111) is an abutting end of the movable lock piece (411), and the movable lock piece (411) comprises a tripping action portion (4112) in transmission connection with the driving end (433); the second locking member (42) is a recess formed in the inner wall of the guide channel (121), and a stop surface (421) is formed in the recess for abutting the abutting end; the other end of the lock spring (412) opposite to the end of the lock spring (412) which abuts the movable lock piece (411) abuts the snap block (2) or the inner wall of the guide channel.
  10. The snap fastening unit according to claim 9, wherein the tripping action portion (4112) is a push arm of the movable lock piece (411), and the driving end (433) is in push-fit engagement with the push arm.
  11. The snap fastening unit according to claim 5, wherein the locking portion (4111) on the movable lock piece (411) is an abutting end located on a side of the rotation center of the movable lock piece (411), the second locking member (42) is a recess formed in the inner wall of the guide channel (121), a stop surface (421) is formed in the recess for abutting the abutting end, the abutting end abuts the stop surface (421) to lock the first locking member (41) with the second locking member (42), a sliding slot (4113) is formed in the movable lock piece (411) and is located between the locking portion (4111) and the rotation center of the movable lock piece (411), an insertion arm (434) is arranged on the triggering member (43), the insertion arm (434) is slidably inserted into the sliding slot (4113) to form a relative sliding engagement between the triggering member (43) and the movable lock piece (411), the insertion arm (434) abuts a side wall (41131) of the sliding slot (4113) which is close to the movable lock piece (411) to form a linkage between the triggering member (43) and the movable lock piece (411) in a rotation direction of the movable lock piece (411); when the head portion (12) is inserted into the through hole in the thin wall (1-1), the periphery of the through hole in the thin wall (1-1) abuts the upper triggering surface (431), and the triggering member (43) abuts a wall of the sliding slot (4113) through the insertion arm (434), driving the movable lock piece (411) to rotate until the abutting end disengages from the stop surface (421); the trigger end reset spring (44) is arranged between the triggering member (43) and the movable lock piece (411), a guide wall (221) that restricts a rotation of the triggering member (43) and guides the triggering member (43) to slide linearly is arranged on the snap block (2); during the process in which the head portion (12) is removed from the through hole in the thin wall (1-1), the lower avoidance drive surface (432) abuts the periphery of the through hole in the thin wall (1-1), and the triggering member (43) slides linearly on the guide wall (221).
  12. The snap fastening unit according to claim 2, wherein an installation groove (22) is formed along a thickness direction of the snap block (2), a corresponding protrusion (23) is formed on the snap block (2) to enclose the installation groove (22); a clamping surface (211) of the clamping head (21) extends to the protrusion (23); the first locking member (41) and the triggering member (43) are both arranged inside the installation groove (22).
  13. The snap fastening unit according to claim 1, wherein the front end surface (21a) of the clamping head (21) has a flat end surface (212) extending from a side of the front end surface (21a) close to the clamping surface (211) to a side of the front end surface (21a) away from the clamping surface (211) along a height direction of the snap block (2).
  14. The snap fastening unit according to claim 13, wherein a chamfered surface (122) is formed on an end corner of the head portion (12) corresponding to an opening of the guide channel (121) and away from the fastening support wall (11), and when the snap block (2) is in the releasing position, a part of the flat end surface (212) of the snap block (2) is capable of protruding out to be exposed outside the opening of the guide channel (121) through the chamfered surface (122).
  15. The snap fastening unit according to claim 1, wherein the snap block (2) comprises a tool engagement portion (24) for engaging with a tool to complete the sliding of the snap block (2) to the releasing position with the tool, and an operation window (123) is formed in the head portion (12) for exposing the tool engagement portion (24); the operation window (123) is located on a side of the fastening support wall (11) facing away from a clamping surface (211) of the snap block (2), and the operation window (123) is covered by a detachable cover plate (14) or directly opened in the head portion (12).

Description

TECHNICAL FIELD The present invention relates to the field of mechanical assembly, and more particularly, to a snap fastening unit used for assembling and fastening a device. BACKGROUND Snap fastening is a cost-effective mechanical fastening solution that requires only a simple mounting hole in a thin wall without using screws. The thin wall can be attached to various components such as housing walls, door leaves, shutters, frames, door frames, or plate-shaped parts, thus, the snap fastening is widely used in various applications; for example, the snap fastening can be used to connect two or more components with the aforementioned thin walls together, or to connect a latch, a handle, or other devices to a frame to a thin wall (as disclosed in the application of a locking device in patent literature NO. CN 217581643U). Various structural forms of snap fastening units have been described in related technologies, such as the simple structural form of a plastic component disclosed in the patent literature NO. US 6042296, and the mechanism formed by multiple components disclosed in the patent literature NO. US 7600794B2, US 8001656B2, and US 8297665B2. The snap fastening unit can be an independent component or a part integrated on related equipment. The snap fastening unit formed by multiple components usually includes a housing having a fastening support wall which limits and supports the thin wall with through holes. The housing further has a seat housing (also known as a head portion) protruding away from the fastening support wall. A snap block capable of sliding horizontally is arranged in the seat housing. The seat housing includes a clamping head engageable with the thin wall to clamp the clamping head onto the thin wall. As the snap block is moveable, the snap block has a fastening position that engages with the fastening support wall to securely clamp the snap block onto the thin wall and a releasing position to release the thin wall along a sliding direction, which allows the snap fastening unit to be disassembled from the thin wall. The snap block is held in the fastening position by a spring. An inclined surface is formed on a side of the snap block that corresponds to an assembly direction of the thin wall supported by the fastening support wall (the direction in which the housing protrudes from the fastening support wall) on the thin wall. During the assembly process, the snap block interacts with a periphery of the through hole in the thin wall. The periphery of the through hole abuts and pushes the inclined surface on the snap block, forcing the snap block to slide until the periphery of the through hole reaches a vertex of the snap block, that is, the snap block retracts to the releasing position. Then, as the periphery of the through hole in the thin wall passes the vertex of the snap block, the snap block is released and returns to the fastening position under a loading force of the spring. The snap block engages with the fastening support wall to fasten the snap fastening unit to the thin wall. The existing snap fastening unit formed by multiple components has defects as follows. When no compressive forces are applied to the snap block, the snap block remains in a protruding fastening position under a driving force of the spring, which thus requires the inclined surface formed on the snap block. When the snap fastening unit is fastened to the thin wall, the inclined surface guides the periphery of the through hole in the thin wall to press the snap block to slide and avoid the thin wall, thus, the force required to keep the snap block fastened to the thin wall becomes a resistance during the assembly process. The resistance accompanies the entire assembly process and continues to increase until the periphery of the through hole in the thin wall passes the vertex of the snap block. On the one hand, when a strong force is required to keep the snap block fastened to the thin wall, the snap fastening unit cannot be inserted into the through hole in the thin wall with a low resistance; on the other hand, during occasional maintenance or disassembly, whenever it is necessary to detach the snap fastening unit from the thin wall, the operator needs to use a separate tool to maintain the snap block compressed inside the housing (due to the inclined surface, it is difficult to directly press the snap block manually, thus, a tool is required to press the snap block), and simultaneously remove the snap fastening unit from the hole in the thin wall, making the disassembly operation inconvenient. SUMMARY To overcome the shortcomings of the prior art, the present invention aims to provide a snap fastening unit with a snap block capable of maintaining in a retracted state, having the advantages such as quick and easy assembly and disassembly, and low insertion resistance. To achieve the above objectives, the present invention provides the following technical solutions: A snap fastening unit for being fastene