DE4313763A1 - Open bicycle frame - Google Patents

Abstract

When transporting loads or children stable bicycle frames with a low opening are important in order for it to be possible to get on/off the bicycle, even when the rear luggage carrier is well loaded, without having to swing the leg over the latter. However, ladies' and Berceau frames are unstable. (Cross)mixed frames are sufficiently stable for conveying, for example, 2 children, but are often not sufficiently far drawn down. In addition, cross-mixed frames are expensive to manufacture. Berceau frames are unstable because the upper tubes are not supported upwards/downwards at the bend. According to the invention, Berceau frames are reinforced by reinforcements (8), (10) engaging on the bends of the upper tubes in the direction of the saddle pillar or bottom-bracket bearing. In this manner, bicycles can be manufactured which despite having a low opening are approximately as stable as men's frames but hardly more expensive/heavy than Berceau frames. <IMAGE>

Description

Men's bikes or diamond frames have the disadvantage that Loads on the rear rack that overlaps the saddle barely put your leg over the same to get on / off can be swing. If necessary, you can with appropriate Flexibility also pull the leg out from behind the control head but there is always the risk of getting caught given a bad fall afterwards.

Therefore z. B. transporting children on the back Carrier of a men's bike unfavorable. Should be additional a child is sitting in front of the driver if the luggage rack is too heavily loaded zen - mostly between this and the control head because it's there would also be dangerous before - getting on / off to a difficult and at least in emergency situations dangerous endeavors.

There are also frames with a slightly lowered access, so-called called mix frames with two straight from the control head to the rear dropouts running upper tubes known. Also Frame with the top tube pulled down and in its extension struts can be used when processing according to the State of the art with approximately the strength (especially Torsional rigidity) of diamond frames the. They hardly have to be heavier than this.

But you still have the disadvantage that the climb is quite high. In particular, if still a child seat behind the handlebars are for up / down Quite contortions rise. In emergency situations you’re likely to get stuck.  

If the wheel z. B. ge via the station stairs (bike & ride) should be worn, it can not ge like a men's bike to be shouldered. When wearing on one of the sloping tops this is very uncomfortable in the hand. Also Carrying out of the bike cellar is as uncomfortable as necessary.

So-called women's bicycles are common worldwide characterized by a deep step, e.g. B. in the form of Gooseneck frame. Getting on and off is more convenient than for diamond frames. But they have to be a lot heavier than this and frame damage due to overload are anyway spread.

Worldwide there are so-called Berceau frames with two waiters pipes spread through a deeper climb distinguish as a mix frame. Their top tubes are in the loading richly bent or curved the seat tube.

In most cases, your ascent is sufficiently deep, but these frames are like other women's frames for deficiency known driving characteristics. Especially with heavy ones and movable (children) loads in front and back they even pose a safety risk because the driver is in Extreme situations easily mastery of the wheel loses.

So-called cross mix frames are also known - with two straight from the lower end of the control head to the rear Dropouts running top tubes and a thick Center tube that extends from the top of the control head to the Seat tube extends just above the bottom bracket.

They offer a deeper climb than normal mixes frame and are so ver according to the prior art Stiff to build that taking two children with you therefore no problems. However, the In this case, climbing through is not sufficient.  

But they are above all one with the same choice of material heavier and more expensive than mix frames. Since they have many ver soldering (& sockets...) require that on mixte and others Frames are unusual, the price can be little reduce.

The object of the invention is therefore to provide frames that in most cases a sufficiently deep step to offer. They should have such a high stability or ver have stiffness and no rolling that sufficient when transporting two light children Driving safety is guaranteed. Even when transporting 50 kg of luggage should not create an unsafe driving feeling.

For this basic version is supposed to be known by adopting it Mixer frames an inexpensive manufacture or even Rectification may be possible.

This is achieved through the characteristic features of the Claim 1.

Torsion tests have shown that Berceau frames a Have weakness. With almost all forces working on the Act on the frame, the two top tubes move up and down from. The fasteners with which they are attached to the seat tube attached, cannot withstand this movement, because they are sheets or tubes that are direct extend from one top tube to another. The forces that stretch or compress the top tubes, but kick about vertically right to the fasteners.

As a result of this constant alternating loads are found Fatigue cracks on the solder on many older Bercea frames provide the fasteners. These rarely tear through, but weaken the already poor construction additionally in terms of driving stability.  

In Fig. 2 it is shown how a normal, unreinforced Berceaur frame behaves under a typical load. The down tube ( 4 ) can be taken approximately as a torsion axis ( 10 ), although this only approximates the actual conditions. The rear triangle of the frame made of lower struts, upper struts and seat tube ( 2 ) is considered to be fixed. Now moves z. B. a child in a seat attached to the control head ( 3 ) in the direction of the trachters, so acts on the frame a force in the direction of the black arrow about the torsion axis ( 11 ).

The upper tube ( 5 a) closer to the viewer is compressed and deflected downward at the location of the bend ( 7 a). The opposite top tube ( 5 b) is stretched at the location of the kink ( 7 b) and thus deflected upwards.

The essential difference in stability between the Mixte and Bercea frame can therefore be eliminated if deflection is prevented at the location of the kink ( 7 a, b). This could be done by massive construction of the top tubes ( 5 a, 6 ) or connecting parts ( 6 a, b). This construction would be unnecessarily difficult.

According to the invention, the provision of reinforcing elements ( 8 a, b) is proposed, which transmit the forces acting perpendicular to the top tubes ( 5 a, b) to the bottom bracket ( 9 ) or seat tube ( 2 ), also indirectly.

In Fig. 1, a reinforcing element ( 8 a) is shown in the form of a tube, which is soldered to the top tube ( 5 a) and on the seat tube ( 2 ) above the top tube ( 5 a). In addition, a Bowden cable counter-holder ( 12 ) is provided, which is attached to the lower tube ( 4 ) so that the brake cable runs correctly ver. With normal Berceau frames, the Bowden cable is often angled upwards, which leads to poorer efficiency and increased wear and deterioration in access.

The top tubes are butted, which with the same stability reduces weight and makes it look more elegant.

In Fig. 3 a heavy duty city bike version is shown. The frame is stiffened between top tubes ( 5 a, b) and down tube ( 4 ) by further reinforcing components ( 10 a, b). This ensures adequate driving safety when transporting two children with luggage or with any distribution (low-rider or frame-fixed luggage rack at the front ...) of 70 kg of luggage.

In addition, the bike should fit comfortably in your hand and offer a particularly easy step through. Therefore, the top tubes ( 5 a, b) are bent down at the location of the first kink ( 7 a, b).

In order not to have to pull the saddle struts too far forward (luggage rack is crooked ...) and still be able to mount the saddle particularly deep, the saddle tube clamp ( 2 a) was turned around and the saddle struts were soldered on.

A reinforcing element ( 8 a) is drawn in, which merges into the connecting element ( 6 ) and is connected to the seat tube ( 2 ) via the upper tubes ( 5 a, b). So the bike can be carried particularly comfortably on the horizontal top tube ( 5 a). For certain brake dimensions, however, it may make more sense to let the reinforcing element ( 8 a) pass down onto the seat tube ( 2 ).

The down tube ( 4 ) is pulled slightly forward to create more clearance from the top tubes ( 5 a, b) and a correspondingly higher torsional stiffness when climbing deep.

Fig. 4 shows two with the connecting element ( 6 ) punched out, angled down reinforcing elements ( 8 a), (solderable in one operation). This essential reinforcement hardly increases the cost of production.

Reference list

Seat tube ( 2 )
Seat tube clamp ( 2 a)
Control head ( 3 )
Down tube ( 4 )
Top tubes ( 5 a, b)
Connecting elements ( 6 a, b)
Locations ( 7 a, b) where the top tubes ( 5 a, b) are bent vertically
stiffening elements ( 8 a, b) which engage on top tubes ( 5 a, b)
Bottom bracket ( 9 )
further stiffening components ( 10 a, b), which connect the top tubes ( 5 a, b) with each other, with the down tube ( 4 ) or the control head ( 3 )
Torsion axis ( 11 ) is assumed to be the central axis of the down tube
Bowden cable counterholder ( 12 )

Claims (11)

1. Open bike frame, which consists mainly of seat tube ( 2 ), steering head ( 3 ), down tube ( 4 ) and 2 top tubes ( 5 a, b), the top tubes ( 5 a, b) via a ( 6 ) or Several horizontal connecting elements ( 6 a, b) are connected to each other and to the seat tube ( 2 ) and are bent at least at one location ( 7 a, b) in the vertical direction, characterized in that the locations are vertical Bending ( 7 a, b) of the top tubes ( 5 a, b) in addition to the connecting element ( 6 ) or ( 6 a, b) attacks at least one stiffening element ( 8 a, b) per top tube ( 5 a, b) which connects the respective top tube ( 5 a, b) in the vertical or approximately vertical direction with the seat tube ( 2 ) or bottom bracket ( 9 ). 2. Bicycle frame according to claim 1, characterized in that the stiffening elements ( 8 a, b) are combined in one component. 3. Bicycle frame according to claim 1, characterized in that the connecting elements ( 6 a, b) are made in one component with the ver stiffening elements ( 8 a, b). 4. Bicycle frame according to claim 1, characterized in that the stiffening elements ( 8 a, b) consist of tubes. 5. Bicycle frame according to claim 1, characterized in that the stiffening elements ( 8 a, b) consist of stamped parts. 6. Bicycle frame according to claim 1, characterized in that the stiffening elements ( 8 a, b) above the upper tubes ( 5 a, b) on the seat tube ( 2 ) attack. 7. Bicycle frame according to claim 1, characterized in that the stiffening elements ( 8 a, b) below the upper tubes ( 5 a, b) on the seat tube ( 2 ) attack. 8. Bicycle frame according to claim 1, characterized in that the stiffening elements ( 8 a, b) above the upper tubes ( 5 a, b) on the bottom bracket ( 9 ) attack. 9. Bicycle frame according to claim 1, characterized in that the upper tubes ( 5 a, b) by further stiffening components ( 9 a, b) with each other, with the down tube ( 4 ) or the control head ( 3 ) are connected, which also in can be made in one piece with the connecting elements ( 6 a, b) or stiffening elements ( 8 a, b). 10. Bicycle frame according to claim 1, characterized in that the upper tubes ( 5 a, b) are butted inside or outside. 11. Bicycle frame according to claim 1, characterized in that a Bowden cable counterholder ( 11 ) is attached to the stiffening components ( 9 a, b) between upper ( 5 a, b) and lower tubes ( 4 ) or on the down tube ( 4 ), so that its central axis points to a rim brake on the connecting elements ( 6 a, b).