Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B19/00—Bolts without screw-thread; Pins, including deformable elements; Rivets
  • F16B19/04—Rivets; Spigots or the like fastened by riveting
  • F16B19/08—Hollow rivets; Multi-part rivets
  • F16B19/10—Hollow rivets; Multi-part rivets fastened by expanding mechanically
  • F16B19/1027—Multi-part rivets
  • F16B19/1036—Blind rivets
  • F16B19/1081—Blind rivets fastened by a drive-pin

Definitions

• the present invention relates to a device for fixing an element to a thin support, comprising a hooking part which can be engaged from the front in a hole in the support and a blocking part which, by driving into the part d 'hanging, ensures the expansion of the latter and its attachment to the support.
• the blocking part which is pressed into the hooking part for the expansion of the latter cannot be withdrawn towards the rear for disassembly, the only possibility of disassembly consisting in driving this blocking part forward.
• the blocking part driven through the hooking part generally falls into a hollow body d '' where it can often not be removed and in which it therefore generates noises.
• the attachment part generally undergoes permanent deformation during its expansion and is therefore degraded following disassembly.
• the present invention relates to a blind fastening device which, while being of simple structure, allows easy disassembly with recovery of all parts of the device, without any degradation.
• the blocking part comprises an external thread and the hooking part has internally means for taken to cooperate with the threading of the blocking part in order to ensure, after being inserted into the hooking part, with a view to the expansion of the latter, the axial immobilization of the blocking part in the part of expanded attachment while allowing the unscrewing of the blocking part for disassembly of the device.
• the attachment portion comprises at least two opposite attachment branches connected to each other at a first end and carrying each internally said gripping means in the vicinity of their second end.
• Said gripping means can advantageously be constituted by thread sections.
• at least the thread of one of the parts is a thread with a sawtooth profile.
• Each hooking branch may advantageously comprise an elastic loop shaped so as to undergo, when the locking part is pressed into the hooking part engaged in the hole of the support, elastic bending with axial crushing and radial expansion of the loop in front of the support.
• Each loop can advantageously be extended towards the free end of the attachment branch by a spout having internally said gripping means and externally a profiling improving the attachment in the hole of the support.
• the blocking part may include at its rear end an imprint for the engagement of a unscrewing tool, preferably a transverse slot for the blade of a screwdriver.
• the first ends of the attachment branches are connected to each other by an annular connection portion and the blocking part comprises at its rear end means for its axial immobilization in said annular connection portion.
• Said axial immobilization means may preferably comprise latching means allowing the engagement and axial immobilization of the rear end of the locking part in said connecting portion of the latching branches before mounting.
• said latching means can advantageously be constituted by external projections on the two opposite sector-shaped portions that said transverse slot delimits at the rear end of the blocking part .
• an element 1 is intended to be fixed to a flat support 2, for example made of sheet metal, having a hole 3 at the place of fixing.
• the fixing is carried out using a device 4 which consists of a hooking part 5 made in one piece with the element 1, and a separate blocking part 6.
• the attachment portion 5 essentially comprises two opposite attachment branches 7, connected to one another at one of their ends by an annular connection portion 8, the latter being in turn connected to the element 1 by a portion of tubular junction 9.
• the connecting portion 8 has an inner diameter smaller than the inner diameter of the joining portion 9, so that a shoulder 10 remains at the point of connection of the connecting portion 8 with the joining portion 9, a shoulder whose function will appear later.
• the hooking branches 7 each comprise a loop 1 1, one end of which is connected to the connecting portion 8 and the other end of which is extended by a hooking spout 12.
• the hooking spout 12 of each branch 7 comprises internally, that is to say on the side facing the opposite branch 7, gripping means 13 constituted for example by several teeth or thread sections staggered in the direction of the length of the spout 12.
• gripping means 13 constituted for example by several teeth or thread sections staggered in the direction of the length of the spout 12.
• the spout 12 has a groove 14 extending transversely to its length and flanked on the side facing the free end of the spout 12 by a boss 15 and on the side facing the loop 11 by a boss 16 which can possibly assume a function of sealing.
• the locking part 6 has the general shape of a screw, comprising a point 17 in a truncated cone followed by a barrel 18 provided with a thread 19 with a sawtooth profile.
• the locking part 6 comprises a collar 20 having a frustoconical front flank 21 and a rear flank 22 perpendicular to the axis of the part 6.
• the collar 20 is followed towards the rear end of the part 6, by a cylindrical section 23 whose reduced diameter is substantially equal to the diameter of the bore of the annular connection portion 8, and whose length corresponds to the length of said bore.
• the blocking part 6 ends in a frustoconical section 24.
• the locking part 6 has, in its rear end zone, a diametrical transverse slot 25 extending over a depth sufficient to divide the rear end zone into two sectors having a certain elasticity in bending.
• Each of said sectors carries, on the frustoconical portion 24, a projection 26 preferably located in an angular position offset by 90 ° relative to the plane of the slot 25.
• the protrusions 26 thus constitute latching means by which the locking part 6 can, after pressing its rear end into the connecting portion 8, be immobilized axially relative to the latter, therefore relative to the element 1 to to stare.
• the assembly is presented in the position according to FIG. 1, by engaging the end of the spouts 12 in the hole 3. It then suffices to push the element 1 against the support 2, for example by a pressure exerted with the palm of the hand on the element 1 in the area of the junction portion 9, to push the locking part 6 between the spouts 12 of the two branches 7.
• This simultaneously causes a bending of the loops 1 1 in the direction of crushing the loops 11, and an outward bending of the spouts 12, including a spacing of the spouts 12 behind the support 2 (expansion of the attachment portion 5), ensuring the attachment of the spouts 12 to the hole 3 of the support 2.
• the insertion of the blocking part 6 into the attachment part 5 can continue until the loops 11 are completely flattened, as shown in FIG. 2 , thread 19 of the blocking part 6 clinging in this position to the teeth 13 of the spouts 12, so that the element 1 is held firmly in the position shown in FIG. 2.
• the fixing device according to FIG. 3 differs from the device according to FIGS. 1 and 2 only in that the attachment part 5 is produced separately from the element 1 to be fixed, instead of being made in one piece. with the latter.
• the junction portion 9 which extends the annular connection portion 8 of the branches 7 is therefore not integral with the element 1, but has at its free end an outer rim 27 which can be hung behind an inner rim 28 of the element 1 to fix. Where appropriate, by an appropriate conformation of the rim 27 and / or the rim 28, it is possible to establish a connection in rotation between these two parts.
• the element 1 to be fixed comprises, along the axis of the blocking part 6, a hole 29 allowing the engagement of a screwdriver to unscrew, for the purpose of dismantling the device, the locking part 6 provided with a transverse slot 25 at its rear end.
• the device according to FIG. 3 operates in the same way as the device according to FIGS. 1 and 2.
• the attachment portion 5 is molded in one piece from plastic, for example polyamide.
• the molding of the hooking part 5 can be considerably simplified by the fact that the two hooking branches 7 are molded flat and are brought only to the mounting in the position according to FIGS. 1 and 3, position in which the two nozzles 12 are brought together for insertion into the hole 3 of the support 2, by bending the loops 11 of the branches 7.
• the axial immobilization of the blocking part 6 relative to the connecting portion 8 of the arms 7 of the hooking part 5 could also to be done for means other than the collar 20 and the projections 26, which allow such immobilization by snap-fastening, before mounting, so that mounting can then be done by a simple pressure exerted on the element 1 to be fixed. It would be possible, for example, to remove the collar 20, and to provide an outer rim at the rear end of the blocking part 6. In this case, the blocking part 6 should be engaged by its point 17, through the connecting portion 8, until its outer edge comes to bear against said connecting portion.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Dowels (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1997
  • 1997-05-20 FR FR9706116A patent/FR2763657B1/fr not_active Expired - Fee Related
• 1998
  • 1998-05-20 WO PCT/FR1998/001004 patent/WO1998053214A1/fr not_active Ceased
  • 1998-05-20 EP EP98925751A patent/EP0983443A1/de not_active Withdrawn

Non-Patent Citations (1)

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