WO2012143957A1

WO2012143957A1 - Frame for bicycle

Info

Publication number: WO2012143957A1
Application number: PCT/IT2011/000123
Authority: WO
Inventors: Giovanni MOLETTA
Original assignee: Jonny Mole Design
Priority date: 2011-04-19
Filing date: 2011-04-19
Publication date: 2012-10-26

Abstract

A frame for bicycle, comprising: a top tube (2) provided with a front end (2a) and a rear end (2b); a down tube (3), provided with a front end (3a) and a rear end (3b), which is connected to the front end (2a) of the top tube (2) at the front end (3 a) thereof; two chain stays (4) flanked to one another, provided with a front end (4a) and a rear end (4b), each of which is connected to the rear end (3 b) of the down tube (3) at the front end (4a) thereof; two seat stays (5) flanked to one another, provided with a front end (5a) and a rear end (5b), each of which is connected to the rear end (4b) of a chain stay (4) at the rear end (5b) thereof; a seat tube (6), predisposed to house a portion of a seat post (7), which is provided with a lower end (6b), connected to the down tube (3) and to the chain stays (4), and a free upper end (6a), arranged inferiorly of the top tube (2) and not joined to the top tube (2).

Description

TITLE

Frame for Bicycle

Description

Technical Field

The present invention relates to a frame for bicycle.

In particular, though not exclusively, the invention relates to a frame for a competition bicycle.

Background Art

From a structural point of view, a common frame for bicycle is made up of a determined number of tubular elements, known in the sector as tubes or stays, which are connected to one another substantially to form two triangles.

In greater detail, and with reference to figure 3, which illustrates a traditional frame, a first triangle is formed by a top tube 101 , a down tube 102, and a seat tube 103 which are connected to one another at ends thereof. A second triangle is formed by the seat tube 103, by a pair of chain stays 104 and a pair of seat stays 105 connected to one another at ends thereof. The top tube 101 and the down tube 102 are connected, at a front end, to a tubular element, known as a head tube 106, which lies on a vertical plane. The head tube 106 is the seating for the coupling between the frame and the front fork 107. The down tube 102, the seat tube and the chain stays are connected to another tubular element 108 that is only partially visible in figure 3, known as the node of bottom bracket axle 108, which is horizontally arranged and defines the seating of the coupling between the frame and the bottom bracket axle of the bicycle. The chain stays and the seat stays are connected to one another in twos at two shaped plates 109, called forks, which are opposite one another and are provided with a seating for housing and fastening the rotation pivot 110 of the rear wheel. The seat tube, the top tube 101 and the seat stays are connected to one another at a node 111 known as the saddle node. The seat tube, which is superiorly open, is destined to house the seat post 112, which, evidently, supports the saddle 113.

In the manufacturing of traditional frames the various tubes or stays, which are made of aluminium and/or steel, are coupled to one another by welding or brazing, using pipe-joint connections. This type of connection between the various tubes or stays is not however usable in a case in which a frame is to be made of composite and light material, such as for example carbon. At present the production of carbon frames is done by casting. The technical specifications required for making the joints between the tubes or stays are rather complex and laborious, to the point of making the production of carbon frames rather expensive. In particular, a rather critical zone of the frame from a manufacturing viewpoint is constituted by the joint between the top tube, the seat tube and the seat stays.

The aim of the present invention is to provide a bicycle frame which is simpler to realise with respect to known-type frames, in particular using carbon or carbon fibre.

An advantage of the frame according to the present invention is that it considerably simplifies the connection of the top tube and the seat stays.

Disclosure of Invention

Further characteristics and advantages of the present invention will better emerge from the non-limiting description, given by way of example in the following with reference to the accompanying figures of the drawings, in which:

figure 1 is a schematic view in vertical elevation of a first embodiment of the frame;

figure la is an enlarged view of a part of the frame of figure 1 ;

figure 2 is a schematic view in vertical elevation of a second embodiment of the invention;

figure 2a is an enlarged view of a part of the frame of figure 2;

figure 3 is a schematic view of a traditional frame.

With reference to the above-cited figures, the frame 1 of the present invention comprises a top tube 2 provided with a front end 2a and a rear end 2b. A down tube 3, provided with a front end 3a and a rear end 3b, is connected to the front end 2a of the top tube 2 at the front end 3a thereof. The down tube 3 extends, diverging from the top tube 2 towards the rear end 3b thereof. In the join zone between the front ends 2a, 3a, the top tube 2 and the down tube 3 form a front joint 23 which is shaped such as to define a seating for rotatable coupling of a front fork 9 to the frame 1.

The frame 2 further comprises two chain stays 4, flanked to one another, which are provided with a front end 4a and a rear end 4b. Each of the chain stays 4 is connected to the rear end 3b of the down tube 3 at the front end 4a thereof. In the join zone between the rear end 3b of the down tube 3 and the front ends 4a of the chain stays 4 a centre joint 34 is formed. Such centre joint 34 is shaped such as to house a bottom bracket axle of the bicycle. The chain stays 4 extend from the centre joint 34 and diverge from one another.

A seat tube 6 is also connected to the centre joint 34 and therefore also to the rear end 3b of the down tube 3 and to the front ends 4a of the chain stays 4. Such seat tube 6 is provided with a lower end 6b, at which it is connected to the rear end 3b of the down tube 3 and the front ends 4a of the chain stays 4 in the zone of the centre joint 34. The seat tube 6 is further provided with a free upper end 6a, arranged inferiorly of the top tube 2 and not joined to the top tube 2. This offers a first important simplification in the realisation of the frame, as the seat tube 6 exhibits a length which is considerably smaller than the length thereof in traditional frames, in which the seat tube 103 extends from the centre joint 108 to the saddle node 11 1 (figure 3). At the upper end 6a thereof, the seat tube is provided with an opening through which a seat post 7 can be inserted. A first fastening device 61, for example a band clamp or the like, is predisposed to removably fasten the seat post 7 to the seat tube 6, such that the seat post 7, once fastened, cannot slide axially with respect to the seat tube 6. Thanks to the special conformation of the seat tube 6, the seat post 7 assumes a structural function in the frame 1, as it enables connecting the centre joint 34 to the top tube 2. Further, the seat post 7 is interchangeable with respect to the frame 1 , such that it is possible to choose a seat post 7 made of the most appropriate material, for example steel, carbon, titanium or aluminium, with the aim of giving a desired rigidity to the frame.

The frame further comprises two seat stays 5, flanked to one another, which are provided with a front end 5 a and a rear end 5b. Each upper seat stay 5a is connected to the rear end 4b of a chain stay 4 at the lower end 5b thereof. As can be seen in figures 1 and 2, the chain stays 4 and the seat stays 5 are connected to one another in pairs at two shaped plates 45, known as forks, which are opposite one another and are provided with a seating for housing and fastening the rotation pivot 130 of the rear wheel 13. The seat stays 5 extend from the shaped plates 45 towards the top tube 2, and converge towards one another. In a first embodiment of the frame, illustrated in figure 1, the front ends 5a of the seat stays 5 are free and predisposed to be connected to a seat post 7. In this embodiment, the rear end 5b of the top tube 5 is also free and predisposed to be connected to the seat post 7. In this embodiment too, the seat post 7 has a structural function in the frame, as it conjoins the centre joint 34 with the top tube 2 and with the seat stays 5. Consequently it is not necessary to realise the saddle node 11 1, i.e. the join zone between the top tube 101, the seat tube 103 and the seat stays 105 which is present in traditional frames (figure 3). This considerably simplifies the realisation of the frame.

The top tube 2 is provided with a second fastening device 21, located in proximity of the rear end 2 thereof, which is predisposed to removably fasten the seat post 7 to the top tube 2. Preferably, though not exclusively, the second fastening device 21 comprises a curved element 21 which can be removably fixed and blocked to the rear end 2b of the top tube 2, for example by means of two screws. The rear end 2b is provided in turn with a seating, not visible in the figures, shaped such as to house a portion of the seat post 7, such that the seat post 7 can be blocked between the curved element 21a and the rear end 2b of the top tube 2. The two fastening screws, by means of which the seat post 7 can be blocked, are located on opposite sides of the seat post 7.

Likewise a third fastening device 51 , located in proximity of the front end 5a of the seat stays 5, is predisposed to removably fasten the seat post 7 to the seat stays 5. Preferably, though not exclusively, the third fastening device 51 comprises a curved element 51a predisposed to be removably fixed and blocked to the front ends 5 a of the seat stays 5, for example by means of two screws located in end positions on the curved element 51a itself. The front ends 5a of the seat stays 5 form a seating, not illustrated in the figures, shaped in such a way as to house a portion of the seat post 7. The seat post 7 can therefore be blocked between such seating of the seat stays 5 and the curved element 51a. The two fastening screws, by means of which it is possible to perform the blocking of the seat post 7, are on opposite sides of the seat post 7.

In a second embodiment of the frame, illustrated in figure 2, the front ends 5a of the seat stays 5 are removably associated to the rear end 2b of the top tube 2. In particular, the front ends 5 a of the seat stays 5 form a first seating shaped such as to be able to house a portion of the seat post 7. Similarly, the rear end 2b of the top tube 2 is shaped such as to define a second seating suitable for housing a portion of the seat post 7. The first and the second seatings are predisposed such as to be tightened to one another such as to block the seat post 7 and prevent it from getting displaced. In this second embodiment too, then, the saddle node 11 1 is not necessary, thus simplifying the realising of the frame. The above-described first and second seatings can be blocked to one another by means, for example, of two screws arranged on opposite sides of the seat post 7.

In a further advantageous embodiment of the frame, which can be combined with both above-described embodiments, each seat stay 5 is connected to the respective chain stay 4 by means of a rotating and/or demountable hinge. This hinge can be located at the lower end 4b of the chain stay 4, or can be arranged on the shaped plate 45.

In the first embodiment of the frame, illustrated in figure 1, the rotating hinges between the chain stays 4 and the seat stays 5 enable the position of the connection between the seat stays 5 and the seat post 7 to be changed. The seat stays 5 can be removably constrained to the chain stays 4, such that the frame can be realised without the presence of the seat stays 5, which can be made separately and subsequently connected to the frame. As in the case of the seat post 7, the seat stays 5 could also be made of a different material to that of the frame, for example steel, carbon, titanium or aluminium, and in this way this part of the frame, and even the frame in its entirety, can be given precise characteristics of resistance and rigidity. The forms and the sections of tubes or stays which make up the frame can be very different, and the description is not limited to those illustrated in the appended figures.

The frame according to the present invention offers important advantages. It is considerably simpler to realise with respect to traditional frames, especially with casting procedures. The absence of the saddle node considerably simplifies the casting of the frame. The shorter seat post, which does not join to the top tube, further limits the overall weight of the frame. The frame further enables interchangeability of the seat post and the seat stays, which can be made of different materials.

Claims

Claims.

1) . A frame for a bicycle, comprising: a top tube (2) provided with a front end (2a) and a rear end (2b); a down tube (3), provided with a front end (3 a) and a rear end (3 b), which is connected to the front end (2a) of the top tube (2) at the front end (3 a) thereof; two chain stays (4) flanked to one another, provided with a front end (4a) and a rear end (4b), each of which chain stays (4) is connected to the rear end (3 b) of the down tube (3) at the front end (4a) thereof; two seat stays (5) flanked to one another, provided with a front end (5a) and a rear end (5b), each of which seat stays (5) is connected to the rear end (4b) of a chain stay (4) at the rear end (5b) thereof; characterised in that it comprises a seat tube (6), predisposed to house a portion of a seat post (7), which is provided with a lower end (6b), connected to the down tube (3) and to the chain stays (4), and a free upper end (6a), arranged inferiorly of the top tube (2) and not joined to the top tube (2).

2) . The frame according to one of the preceding claims, wherein the seat tube (6) is provided with a first fastening device (61) predisposed to removably fasten a seat post (7) to the seat tube (6).

3) . The frame according to claims 1 or 2, wherein the front ends (5a) of the seat stays (5) are free and predisposed to be connected to a seat post (7).

4) . The frame according to one of the preceding claims, comprising a second fastening device (21), located in proximity of the rear end (2b) of the top tube (2), predisposed to removably fasten a seat post (7) to the top tube (2).

5) . The frame according to claim 4, wherein said second fastening device (21) comprises a curved element (21) that is removably fastenable and blockable to the rear end (2b) of the top tube (2), the rear end (2b) being provided in turn with a shaped seating for housing a portion of the seat post (7), such that the seat post (7) can be blocked between the curved element (21a) and the rear end (2b) of the top tube (2).

6) . The frame according to any one of the preceding claims, comprising a third fastening device (51) located in proximity of the front end (5 a) of the seat stays (5), predisposed to removably fasten a seat post (7) to the seat stays (5).

7) . The frame according to claim 6, wherein said third fastening device (5 Ϊ) comprises a curved element (51a) removably fastenable and blockable to the front ends (5 a) of the seat stays (5), said front ends (5 a) of the seat stays (5) being conformed such as to form a seating which is suitable for housing a portion of the seat post (7), such that the seat post (7) can be blocked between said seating of the front ends (5 a) of the seat stays (5) and said curved element (51a).

8) . The frame according to claims 1 or 2, wherein the front ends (5a) of the seat stays (5) are associated to the rear ends (2b) of the top tube (2).

9) . The frame according to claim 8, wherein: the front ends (5a) of the seat stays (5) form a first shaped seating for housing a portion of the seat post (7); the rear end (2b) of the top tube (2) is shaped such as to define a second seating suitable for housing a portion of the seat post (7); said first and second seatings are predisposed to be tightened to one another such as to block the seat post (7).

10) . The frame according to claim 1 , wherein each seat stay (5) is connected to the respective chain stay (4) by means of a rotatable hinge.

1 1) . The frame according to claim 10, wherein said rotatable hinge is interposed between the rear end (4b) of the chain stay (4) and the lower end of the seat stay (5). 12). The frame according to claim 10, wherein said rotatable hinge is interposed between the lower end of the seat stay (5) and a shaped plate (45) to which the rear end (4b) of the chain stay is also associated.