Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62K—CYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDE-CARS, FORECARS, OR THE LIKE
  • B62K19/00—Cycle frames
  • B62K19/02—Cycle frames characterised by material or cross-section of frame members
  • B62K19/04—Cycle frames characterised by material or cross-section of frame members the material being wholly or mainly metallic, e.g. of high elasticity
  • B62K19/06—Cycle frames characterised by material or cross-section of frame members the material being wholly or mainly metallic, e.g. of high elasticity tubular
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/12—Electrophoretic coating characterised by the process characterised by the article coated

Definitions

• the present invention relates to the treatment of a bicycle frame, mainly consisting of tubes welded to each other, said treatment comprising at least one step in which the frame is held by a predetermined suspension zone, immersed in a treatment bath, withdrawn of the said bath and drained. It relates more particularly to a treatment method of this type in which it is sought to carry out an effective treatment both of the external surface but also of the internal surface of the frame.
• a bicycle frame is, in a well known manner, a part which consists mainly of a plurality of tubes, welded to each other, to form a monobloc assembly on which are then mounted the other components of the bicycle.
• the use of hollow tubes is required by the fitting, inside the said tubes, of some of these organs, for example the seat tube in which is fitted the rod supporting the saddle, the bottom bracket in which comes to fit the crank axle, the head tube in which comes to fit the steering stem.
• the other tubes are also hollow for the sake of economy and weight gain. The current trend is to offer users of all kinds of bicycles including mountain bikes, all terrain vehicles, which are as light as possible.
• the thickness of the tubes is less important in its middle part. that towards its ends; as an example, the thickness of the horizontal tube may be 0.7 mm towards the seat tube and towards the head tube and may be 0.4 mm in the middle part of the horizontal tube.
• the bicycle frames are treated according to the immersion technique, in which the part to be treated is maintained by a suspension zone, the said part is immersed in a treatment bath for a time sufficient for the bath to produce its Indeed, we remove said part of the bath and let it drain before proceeding to a next step.
• a treatment chain can comprise a succession of treatment baths, comprising degreasing, rinsing, pickling, phosphating and also cataphoresis, anaphoresis or autophoresis baths.
• the metal part to be treated constitutes the cathode and the particles which it is desired to deposit on said part are positively charged.
• the aim set by the applicant is to propose a method of treating a bicycle frame by immersion techniques which overcomes the aforementioned drawbacks because it makes it possible to obtain a particularly effective treatment both on the external surface and on the inner surface of the treated frame.
• the method in question is characterized, according to the invention, in that it comprises a preliminary step consisting in drilling holes in all or part of the tubes constituting the frame to be treated, the location and the dimensions of said holes being such that , after completion of the frame by welding the tubes together, said tubes form, thanks to first internal holes and second external holes, an uninterrupted internal circuit for penetration and evacuation of the treatment bath during immersion and dripping of the frame held by the suspension zone; the second external holes, existing or drilled during the preliminary stage, are located in the zone opposite to the suspension zone and constitute the terminal evacuation orifices.
• the frame when the frame is immersed in the treatment bath, the latter penetrates without any difficulty into the interior volume of the tubes constituting the frame to be treated, due to the presence of the first interior holes forming the uninterrupted internal circuit of penetration of said bath.
• the treatment bath does not accumulate in one or the other of the tubes but is evacuated naturally through this uninterrupted internal circuit and through the second external holes, located in the zone opposite the suspension zone, that is to say towards the bottom of the frame when the latter is held by the suspension zone.
• Such a method has multiple advantages. As regards the anti-corrosion treatment by cataphoresis, there is no longer any foaming problem insofar as this was due to a localized accumulation of the treatment bath. In addition, there is obtained a treatment of the inner surface of the frame which is optimized, being in any case greater than 90% of said surface. This internal surface treatment efficiency, which is true for cataphoresis, is also true for all other immersion treatments, in particular anaphoresis and autophoresis. Finally, incidentally but not negligible, the presence of holes in the tubes reduces the weight of the part. This can be an interesting advantage.
• each first internal hole is drilled in a given tube in the area of overlap of said tube by the adjacent tube.
• the adjacent tube is the tube whose extreme edge is fixed by welding on the outside face of the given tube. In other words the location of each first internal hole is determined so that, after assembly and welding of said tube with the tube adjacent, the hole is in line with the interior volume of the adjacent tube, so that the two interior volumes of the two tubes can communicate, without this being visible from the outside.
• the maximum efficiency with regard to the penetration and evacuation of the treatment bath is obtained with an internal hole of maximum dimension which corresponds to the internal diameter of the adjacent tube in the weld zone.
• the imprecision must be taken into account when assembling and welding the different tubes together.
• the dimension of each first internal hole is between 5 and 15 mm, depending on the internal diameter of the adjacent tube.
• the suspension zone is located at the level of the steering tube and the second outer holes are drilled in the two rear dropouts, provided for mounting the rear wheel, which respectively secure the two guy lines and rear base.
• each rear leg has a curvilinear face, which extends substantially perpendicular to the general direction of the stay and the rear base, two second outer holes being drilled in said curvilinear face, in the extension of the internal volume of the stay on the one hand and the rear base on the other.
• the dimension of the outer holes is of the order of 2 to 5 mm, preferably 3 to 4 mm.
• FIG. 1 is a perspective view of a bicycle frame
• FIG. 2 is a schematic sectional view of the frame of Figure 1
• FIG. 3 is a partial sectional view, in perspective from below, of a bicycle frame at the bottom of the bottom bracket,
• FIG. 4 is a perspective view of a rear leg.
• the present description will relate to the anti-corrosion treatment of a bicycle frame.
• the bicycle frame has the distinction of being made of hollow tubes welded to each other, with an end edge of an adjacent tube which is welded to the outer peripheral face of a given tube.
• the treatments in question they have in common the fact of using an immersion technique in which the frame is suspended by a suspension zone, immersed in the treatment bath for a determined time and drained after having left of the bath.
• a bicycle frame as illustrated in FIG. 1, is composed of nine tubes, namely the head tube 2, the seat tube 3 between which extends in the upper part the horizontal tube 4 and in the lower part the down tube 5, the two rear right 6 and left 6 'stays and the two rear right 8 and left 8' bases.
• a rear shroud 6 joins a rear base 8 at the level of a respectively right rear 9 and left 9 'dropout, said dropouts used for mounting the rear wheel of the bicycle.
• the two rear shrouds 6, 6 ′ are connected by the trigger guard 7.
• the ends of the shrouds 6, 6 'opposite the rear legs 9, 9' are welded to the seat tube 3 substantially at the level of the horizontal tube 4.
• the ends of the rear bases 8, 8 ', opposite the rear legs 9, 9', are welded to the bottom bracket 10 to which the seat tube 3 and the down tube 5 are also welded.
• the objective set by the applicant is to produce a coating by cataphoresis which of course covers the entire external surface of the frame 1 but also almost all of the internal surface of the said frame 1, that is to say the inner surface of each of the nine tubes which have just been recalled.
• the applicant implements, to do this, the so-called cataphoresis technique, in which the metal frame 1 acts as a cathode while the organic fillers which will subsequently constitute the anticorrosion coating are, in the treatment bath, charged positively.
• the frame 1, carried by a swing system is held by the steering tube 2 which constitutes the suspension zone, immersed in the treatment bath for a determined time, then withdrawn from said bath and allowed to drain, before undergoing a subsequent treatment, in particular a heat treatment in an oven, so that the organic charges which have been deposited during immersion constitute the anticorrosion coating proper, for example by virtue of polymerization when these are organic fillers of the epoxy type.
• interior through holes the holes whose function is to connect the interior volumes of two tubes welded to each other.
• the external holes opening out denote the holes made opposite the suspension zone, which allow the evacuation of the treatment bath outside the frame 1.
• nine internal through holes and four external through holes were drilled, namely:
• the two external through holes 18, 19 are made in this face 20. It is understood that in order to have maximum penetration and evacuation of the treatment bath in the interior volume of the frame 1, it would be advisable for the through holes to have the largest possible dimensions.
• the maximum dimension for each internal hole corresponds to the internal diameter of the tube which is welded to the external face, along the periphery of said hole.
• a dimension of less than 5 mm, for example of the order of 3 mm, is possible, but this may either require longer times during the immersion or draining operation or limit the effectiveness of the treatment of the surface. inside the frame.
• the seat tube 3 and the down tube 5 are arranged in the form of a fork, with a certain overlap of the two tubes 3, 5 at the level of the weld zone 22 with the bottom bracket shell 10.
• the internal through hole 21 unique for the two seat tubes 3 and diagonal 5, must necessarily extend sufficiently in this weld zone 22 so as to allow communication between the interior volume of the two seat tubes 3 and diagonal 5 with the interior volume of the bottom bracket 10.
• the same type of embodiment can be envisaged at the joint welding of the two rear shrouds 6, 6 ′ on the outside face of the seat tube 3.
• outer holes 18, 18 ', 19, 19' drilled in the rear legs 9, 9 ' their size is limited by the structure of said legs. It is between 2 and 5 mm, preferably of the order of 3 to 4 mm.
• the treatment bath enters the entire interior volume of the frame 1 and after draining there is no longer any excess bath remaining in one or the other of the tubes.
• an anti-corrosion coating is perfectly distributed over the entire outer surface of the frame but also over almost the entire inner surface of said frame 1, without require recovery of said frame to eliminate any traces of foaming due to the accumulation of the bath in certain parts of the frame.
• anti-corrosion treatment was obtained on substantially the entire interior surface of the frame.
• the present invention is not limited to the preferred embodiment which has just been described by way of non-exhaustive example.
• the suspension zone is not necessarily at the level of the head tube, even if this is the way of doing things that is usually used. It suffices that the part of the opposite part comprises external through holes, these holes being either drilled in accordance with the invention or existing. If, for example, the suspension of the bicycle frame 1 is carried out from the rear legs 9, 9 ′, the external through holes preexist in the case of the two openings 23 through which the steering stem is introduced.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Chemical Treatment Of Metals (AREA)
• Motorcycle And Bicycle Frame (AREA)
• Body Structure For Vehicles (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9506099

Family Applications (1)

Country Status (8)

Families Citing this family (4)

Family Cites Families (2)

• 1997
  • 1997-04-15 FR FR9704848A patent/FR2761946B1/fr not_active Expired - Fee Related
• 1998
  • 1998-04-09 EP EP98920597A patent/EP0904230A1/de not_active Withdrawn
  • 1998-04-09 CN CN98800468.2A patent/CN1222889A/zh active Pending
  • 1998-04-09 TR TR1998/02598T patent/TR199802598T1/xx unknown
  • 1998-04-09 BR BR9804846A patent/BR9804846A/pt unknown
  • 1998-04-09 WO PCT/FR1998/000719 patent/WO1998046476A1/fr not_active Application Discontinuation
  • 1998-04-14 AR ARP980101686 patent/AR015583A1/es unknown
  • 1998-04-15 TW TW87105707A patent/TW391891B/zh active

Non-Patent Citations (1)

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