Patent Application
20070262558
This invention generally finds application in the field of accessories for bicycles and motorcycles and particularly relates to a support frame as defined in the preamble of claim 1, for use in saddles for bicycles, motorcycles and pedal-operated machines, as well as to a process for making same.
A number of support frames for bicycle saddles are known, which have one or two specially-shaped elongate members, generally made of metal or a composite material, which are known in the field as “rails”. The elongate members generally have ends connected to the front and the rear portions of the saddle respectively, and an intermediate portion connected to the bicycle.
A disadvantage of such arrangements lies in their reduced ability to absorb the shock transmitted from the bicycle to the user. The elongate members are designed to exhibit a high fatigue strength and a high yield point and this involves a poorly damped elastic behavior thereof in response to a wide range of stresses.
U.S. Pat. No. 6,343,836, U.S. Pat. No. 5,507,476 and GB-A-2,050,259 disclose support frames having spring means in the proximity of the rear portion of the saddle, which are made of metal. These arrangements may generate undesired oscillations if the spring means have a relatively low stiffness, and have the same problems as the elongate members directly connected to the saddle, if the spring means have a relatively high stiffness. In either case, poor shock absorbing and damping properties result.
U.S. Pat. No. 6,443,524 and U.S. Pat. No. 5,911,473 disclose saddle support frames having shock absorber means interposed between the saddle and a substantially stiff portion of the frame to be attached to the bicycle. These shock absorber means are made of plastic, to obtain a damped elastic behavior therefrom. A disadvantage of this arrangement lies in that shock absorber means can only provide the required resistance and adequate shock absorbing properties if they have a large size. This may result in the shock absorber means being larger than the saddle, which may cause size problems and affect the aesthetic quality of the whole saddle and actual applicability thereof.
Furthermore, the basic plastic material of shock absorber means has a relatively low stiffness which may cause excessive saddle oscillation amplitudes in case of shocks, and force the user to take improper positions.
U.S. Pat. No. 5,692,801 and WO-A-9,525,662 respectively disclose saddle support frames having elastic means and shock absorber means, both interposed between the saddle and a substantially stiff portion of the frame to be attached to the bicycle. Thus, the elastic means and the shock absorber means operate in parallel to absorb the transmitted shocks and simultaneously limit the oscillation amplitudes of the user.
A disadvantage of this arrangement lies in the high complexity thereof, which increases costs and affects reliability with time. Furthermore, since the shock absorber means are located in restricted areas, they shall have a sufficient size to ensure an adequate shock absorbing action, and risk to be excessively bulky and cumbersome.
FR-A-2,768,987, U.S. Pat. No. 6,364,292 and U.S. Pat. No. 5,443,301 disclose shock absorbing arrangements for bicycles, interposed between the saddle and the bicycle frame. These arrangement have the apparent disadvantage of complicating the construction of the bicycle and increasing costs therefor. Also, the provision of shock absorbers at the connection between the bicycle frame and the saddle may hinder or hamper assembly and height adjustment operations. Furthermore, these shock absorbers may cause the saddle to move with respect to the bicycle frame, and force to user to take uncomfortable positions, or repeatedly change his/her posture as he/she pedals.
A primary object of this invention is to obviate the above drawbacks, while providing a cost-effective support frame.
A particular object is to provide a support frame which has high vibration damping properties, while preventing any undesired oscillation of the saddle and the user.
A further object of the invention is to provide a frame that may be easily configured for different types of bicycles, motorcycles, and pedal-operated machines, and may be sized to obtain different shock absorbing properties.
Another particular object is to provide a sturdy and reliable frame, whose features remain unchanged with time.
A further object of the invention is to provide a frame which has a relatively low weight and relatively small overall size.
These objects, as well as other that will be apparent hereinafter, are achieved, according to claim 1, by providing a support frame, particularly for use in a saddle for bicycles, motorcycles and pedal-operated machines, wherein the saddle includes a main body having a tapered front portion and a widened rear portion for supporting the ischial bones of a user, wherein the frame has at least one specially shaped bar having a first end portion securable to the front portion of the main body, a second end portion attachable to the rear portion of the main body and an intermediate portion connectable to the frame of the machine, characterized in that the shaped bar comprises at least one outer tubular element, having internally thereof at least one core element, at least one intermediate layer made of a viscoelastic material being interposed between the tubular element and the core element, to damp bar vibrations.
By this particular arrangement, a frame may be obtained having high vibration damping and shock absorbing properties as well as an adequate stiffness to allow proper user posture.
Further characteristics and advantages of the invention will be more apparent from the detailed description of several preferred, non-exclusive embodiments of a support frame according to the invention, which are described by way of non-limiting examples with reference to the annexed drawings, in which:
Particularly referring to the above figures, a support frame according to the invention is described, which is generally denoted by numeral 1, particularly for use in a saddle S for bicycles, motorcycles and pedal-operated machines.
Saddle S to be supported by the frame 1 includes a main body C having a front portion A that is tapered to assist bicycle or motorcycle riding and a widened rear portion P for supporting the ischial bones of the user.
Frame 1 has at least one shaped bar 2 having a first end portion 3 adapted to be connected to the front portion A of the main body C, a second end portion 4 adapted to be connected to the rear portion P of the main body C and an intermediate portion 5 adapted to be connected to the frame of the machine (not shown in the attached drawings).
A peculiar feature of the invention consists in that the shaped bar 2 has at least one outer tubular element 6 and at least one core element 7 placed internal of the outer tubular element 6. More in detail, in several preferred embodiments, the core element 7 may be substantially coaxial to the tubular element 6. Furthermore, at least one intermediate layer 8 made of a viscoelastic material is interposed between the tubular element 6 and the core element 7. Thus, the vibrations transmitted by the pedal-operated machine cause both the tubular element 6 and the core element 7 to vibrate, but their motion is damped by the intermediate viscoelastic layer 8.
Advantages were particularly found to result from using a viscoelastic gel material, preferably a polyurethane material.
In addition to the shock absorbing action of the viscoelastic material, the amplitude of the vibrations transmitted to the user may be further decreased by differentiating the vibrations transmitted to the tubular element 5 and the aore element 7-Oartiaularlw+ a suitable nhase shift+ nreferablw of 07/+ betueen the vibrations of the tuo elements 5+ 7 is found to be aonsiderablw effeative for shoai absorntion nurnoses. Suah 07/° or similar nhase shift aauses the stresses transmitted to the user bw the vibrating tubular element 5 to substantiallw neutralize the stresses deriving from the vibration of the aore element 7-
The above nhase-shift maw be obtained bw annronriatelw seleating materials and/or sizes of the tubular element 5 and the aore element 7-
Oartiaularlw+ the base materials of the outer tubular element 5 and the aore element 7 maw have differentiated densities+ so as to generate the above mentioned nhase shift. More in detail+ the base material of the aore element 7 maw be brass+ and the base material of the tubular element 5 maw be steel.
Bw suitablw seleating the diameters of the tubular element 5 and the aore element 7+ the vibratorw behavior of the tuo elements 5+ 7 maw be influenaed. First of all+ to allou the vibration of the aore element 7+ the outside diameter D″E of the latter maw be arranged to be smaller than the inside diameter D′I of the tubular element 5. Furthermore+ to imnrove the above nhase shift+ the aore element 7 maw have an outside diameter D″E of 3 to 5 mm+ and the tubular element 5 maw have an outside diameter D′E of 5 to 7 mm+ and a thiainess T of 0 to 0-5 mm-
In certain preferred embodiments, the core element 7, the tubular element 6 and the intermediate layer 8 may extend substantially along the same length, which may be substantially equal to the longitudinal length of the shaped bar 2.
In other preferred embodiments, not shown in the accompanying drawings, the core element 7, the tubular element 6 and the intermediate layer 8 may have different lengths. Particularly, the shaped bar 2 may comprise a plurality of tubular elements 6 externally connected to one core element (7). Thus, the tubular elements 6 may be only placed where they are actually useful for vibration damping purposes. Alternatively, the shaped bar 2 may comprise a plurality of core elements 7 internally connected to one tubular element 6. In this case, the core elements 7 may be suitably spaced inside the tubular element 6 along the shaped bar 2 to maximize the vibration damping effect.
The support frame 1 as described hereinbefore may be fabricated through a process including the following steps.
In a first step a), a tubular element 6 is provided, and in a second step b) at least one elongate core element is provided. Multiple tubular elements 6 or multiple core elements 7 may be also advantageously provided.
In a third step c), the core element 7 is introduced in the tubular element 6 in such a manner as to form a bar 2 with an air space 9 therein, as shown in
If multiple core elements 7 are provided, these will be introduced one after the other in the corresponding tubular element 6. Similarly, if multiple tubular elements 6 are provided, these will be fitted one after the other on the corresponding core element 7.
In a fourth step d), a bar 2 is shaped to be later finished in the subsequent steps, in such a manner as to form a first end portion 3 adapted to be connected to the front portion A of the main body C, a second end portion 4 adapted to be connected to the rear portion P of the main body C and an intermediate portion 5 adapted to be connected to the frame of the machine.
After such shaping step, the bar 2 may undergo one or more heat treatments to provide each tubular element 6 and each core element 7 with the desired mechanical properties, in terms of hardness, and static, fatigue and impact strength. Furthermore, the shaped bar 2 may be suitably surface-treated to obtain an optimal finish thereof.
In a fifth step e), a viscoelastic material is introduced in the air space 9 to form an intermediate layer 8 adapted to damp the vibrations of the bar 2 during operation thereof. Also, the introduction of viscoelastic material may be followed by crosslinking thereof.
More in detail, the step e) of introduction of the intermediate layer 8 may be performed either before or after the shaping step d). The decision as to whether to introduce the viscoelastic material before or after the shaping step depends on the physical properties of the viscoelastic material and, particularly, on its ability to keep its own mechanical properties unchanged when the shaped bar 2 is subjected to heat treatments. Hence, if the viscoelastic material has a low or poor resistance to thermal cycles, it may be advantageously introduced after shaping. However, if the viscoelastic material is unaffected by thermal cycles or if no thermal cycle is provided, the step e) of introduction of the viscoelastic material may be performed before the shaping step d).
The above disclosure clearly shows that the inventive support frame and process fulfill the proposed objects and particularly provide effective damping of the vibrations transmitted to the user, while allowing the user to take and keep an anatomically correct posture.
The support frame and process according to this invention are susceptible to a number of modifications and variants, all falling within the scope of the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.
While the support frame has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.
| Number | Date | Country | Kind |
|---|---|---|---|
| VI2004 A 000130 | May 2004 | IT | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB05/01431 | 5/25/2005 | WO | 11/22/2006 |
