EP0000553A1 - Two-wheeled bicycle-type vehicle - Google Patents

Abstract

A bicycle-like two-wheeler has a frame consisting of four articulated parts (26, 30, 32, 34). The upper frame part (26) carries a saddle (18), the front frame part (30) a handlebar (16) and the front wheel (10) via a front wheel fork (14). The lower frame part (34) forms a rocker mounted on the rear wheel axle (40), which carries a conventional chain drive, the driving sprocket (20) of which is connected to the upper frame part (26) by means of a non-rotatably connected crank (48) and a connecting rod (52). connected is. Footrests (60) are attached to the lower or front frame part. The drive takes place by shifting the weight of the driver alternately on the saddle and the footrests and alternately by pushing or pulling on the handlebar. Between the driven sprocket (40) and the rear wheel hub (72), a rotationally fixed drive connection or a freewheel can optionally be provided, which can be bridged either by a slip clutch or a releasable clutch, or alternatively in combination with spring members (90, 92) acting on the connecting rod finds that overcome the connecting rod's dead positions.

Description

The invention relates to a bicycle-like two-wheel vehicle with chain drive to the rear wheel, a saddle and a front fork rotatably mounted on the frame and connected to a handlebar.

Usually, the frame parts of bicycles are welded or screwed to each other and to the struts of the rear wheel fork. The drive takes place in a known manner by means of foot force via pedals connected to the driving sprocket. The saddle and the front fork bearing are fixed relative to each other and to the frame.

Numerous bicycle-like two-wheeled vehicles have also become known, in which the saddle and handlebar axle and the bottom bracket is movable relative to each other and the rider's feet are moved parallel to each other. The arm and leg movements of the driver should be converted into a drive torque, similar to rowing, for example by means of suitable lever ratios and other gears.

The invention has for its object to provide a particularly suitable as a toy or training device vehicle of the type mentioned, on which the driver executes a very harmonious riding movement covering the entire body, while the weight shift taking place in two phases for driving the driving sprocket over 36o ₀ is used.

The above object is achieved in that the frame consists of four articulated parts, of which the upper frame part carries the saddle, the front frame part the front fork and the lower frame part the rear wheel and the driving sprocket of the chain drive, on the front or lower frame part Footrests are attached and a connecting rod articulated on both sides is arranged between the upper frame part and a crank which is connected in a rotationally fixed manner to the driving sprocket.

The functioning of the new vehicle can best be understood if one assumes that the axis of the driving sprocket while driving makes a circular motion around the lower joint of the connecting rod. In one drive phase, by shifting the weight of the rider onto the footrests connected to the front or lower frame part, the axis of the driving sprocket is pressed down with respect to the connecting rod joint, while in the other drive phase, by shifting weight to the saddle and transferring the Weight force over the rear on the lower frame part acting as a two-armed lever, the axis of the driving sprocket with respect to the lower joint of the connecting rod is raised again. The aforementioned forces are further supported by pulling on the handlebar during the first phase and forward pressure on the handlebar during the second phase.

The rotation of the axis of the driving sprocket around the lower joint of the connecting rod not only generates the tensile force in the chain required to drive the rear wheel, but also causes the saddle to oscillate up and down via the connecting rod and the other parts of the frame which are connected to one another in an articulated manner, an opposite movement of the footrests and a pivoting movement of the handlebar in the direction of travel. These movements give the driver the impression of riding.

In a preferred embodiment of the invention, the articulation points of the front frame part, the connecting rod and the rear frame part are each adjustable on the upper frame part. This results in different strokes and, depending on the location of these joints Seen the extent of one revolution of the driving sprocket, different torque curves. The driver therefore has the power to set a preferred drive characteristic himself.

In a preferred embodiment of the invention, the saddle is also attached to the upper frame part so as to be adjustable in the longitudinal direction.

The driving sprocket is preferably connected to two rectilinear and equally long crank arms, which in turn are articulated with two parallel connecting rods. In this way, significantly lower tilting forces occur in the bearing of the driving sprocket than normally with a bicycle. Because of the more even bearing load, simpler and cheaper bearings, e.g. Bushings made of polyamide or another plastic can be used. Such simple bearings are also suitable for other joints of the frame.

Because of the simpler and cheaper design of the bearings, it may also be expedient to separate the joint between the front and the lower frame part from the bearing of the driving sprocket. In this case it is possible to use a complete conventional bearing for the latter.

To overcome the dead center of the drive movement between the two alternating movement phases, it is advantageous if one rotates between the rear wheel and the driving sprocket by means of the chain

Special measures must be taken if the rear wheel has a freewheel hub, as is the case with bicycles with and without back pedaling as well as with open or hub gear shifting or also a gear shifting. Since in all these cases the freewheel does not generate a sufficiently strong drag torque in order to overcome the two dead positions in which the crank and the connecting rod are aligned, in this application a preferred embodiment of the invention provides a peder mechanism acting between the connecting rod and a frame part , which preferably consists of an articulated with the rear frame part or the connecting rod and with the respective other of these two parts via at least one spring rod.

By jacking up the new device, it can also be used as a so-called home trainer, for the sake of simplicity, the rear wheel by a swing pusher and the front wheel by a rolling, sliding or articulated support supporting the front frame part tion can be replaced.

• Fig. 1 eine schematische Seitenansicht einer ersten Ausführungsform der Erfindung,
• Fig. 2 in Seitenansicht ein gegenüber Fig. 1 abgewandeltes Ausführungsbeispiel,
• Fig. 3 a, b einen Querschnitt und eine Seitenansicht eines Gelenks des Fahrzeugrahmens,
• Fig. 4 einen Teilschnitt durch eine Hinterradnabe, die zur Verwendung bei den Fahrzeugen nach Fig. 1 und 2 geeignet ist.

The invention is explained below with reference to the drawing. Show it:

• 1 is a schematic side view of a first embodiment of the invention,
• 2 shows a side view of a modified embodiment compared to FIG. 1,
• 3 a, b a cross section and a side view of a joint of the vehicle frame,
• Fig. 4 is a partial section through a rear wheel hub, which is suitable for use in the vehicles of FIGS. 1 and 2.

In the drawing figures, corresponding parts have the same reference numerals.

The vehicle shown as an embodiment in Fig. 1 corresponds to a normal bicycle with respect to the wheels 1 ₀ , 12, the front fork 14 and the handlebar 16. Also, the saddle 18 and the chain drive consisting of a front driving sprocket 2 _0, a sitting on the axis of the rear wheel driven sprocket 22 and a chain 24, are commercial parts. The same applies to normal bicycle accessories, such as mudguards,

angebracht, so daß der Achsabstand zwischen den beiden Kettenrädern 2o, 22 konstant ist. Mit dem Kettenrad 2o ist gemäß Fig. 1 zu beiden Seiten des Lagers 46 je eine Kurbel 48 drehfest verbunden. Beide Kurbeln erstrecken sich vom Lager 46 aus in dieselbe Richtung und sind gleich lang. Jede Kurbel 48 ist über ein an ihrem freien Ende angebrachtes Gelenk So mit einer Pleuelstange 52 verbunden, welche am oberen Ende über ein Gelenk 54 am oberen Rahmenteil 26 angreift. Die Gelenke 36 und 54 sind im Beispielsfall mittels Klemmschellen 56 bzw. 58 am oberen Rahmenteil 26 befestigt, so daß sie längs des Rohrs, welches den oberen Rahmenteil 26 bildet, verstellt werden können. Auch der Sattel 18 ist in ähnlicher Weise längs des oberen Rahmenteils verstellbar. Das Gelenk 28 ist gleichfalls mittels einer Klemmschelle 62 verstellbar.

attached so that the center distance between the two sprockets 2o, 22 is constant. 1 sprocket 48 is rotatably connected to both sides of the bearing 46 as shown in FIG. 1. Both cranks extend from the bearing 46 in the same direction and are of the same length. Each crank 48 is connected to a connecting rod 52 via a joint So attached at its free end, which acts on the upper end via a joint 54 on the upper frame part 26. The joints 36 and 54 are attached to the upper frame part 26 by means of clamps 56 and 58 in the example, so that they can be adjusted along the tube which forms the upper frame part 26. The saddle 18 is likewise adjustable along the upper frame part. The joint 28 is also adjustable by means of a clamp 62.

Height-adjustable footrests 60 are attached to the front frame part 3o in the lower region. As can be seen, in the phase of movement in which the driver supports his weight on the footrests 60, the bearing 46 of the driving sprocket 2o together with the front frame part 3o is pressed down with respect to the lower joint 5o of the connecting rod 52. After passing the bottom dead center, the bearing is then raised 46 with respect to the knuckle 5 ₀ again when the driver verlagert.und in the next movement phase of its weight more on the saddle while on the rear frame part 32 of the lower frame portion 34 at about its support the rear wheel axle 4o with reference to the drawing against the

Swiveled clockwise.

The rotation of the bearing 46 about the joint 5o bedsntet because of the rotationally fixed connection between the driving sprocket 2o and the cranks 48, a rotation of the sprocket 2 ₀ , whereby the drive to the rear wheel takes place. Furthermore, the cyclical movement of the crank 48 and the connecting rod 52 brings about an alternating spreading and narrowing of the frame parts 26, 3 ₀ , 32, 34
formed quadrilateral with itself, which leads to the desired relative movement between the saddle 18, the handlebar 16 and the foot rests 6 ₀ .

In a practical embodiment with 26-inch wheels, the upper frame part 26 can have a length of 85 cm and the front frame part 30 between the joints 28 and 38 can have a length of 60 cm. The connecting rods 52 are 38 cm in the example, the cranks 48 are 12 cm, the struts of the rear frame part 32 are 40 cm and the struts of the lower frame part 34 are between the joint 38 and the rear wheel axis 40 mm and in the rear section 44 18 cm long . The distances between the joints on the upper frame part 26 can e.g. be adjusted so that the distance between the joints 28 and 54 50 cm and the distance between the joints 54 and 36 is 25 cm. The joints 42 and 50 contain ball bearings, while the joints 28, 36, 38 and 54 are designed according to FIGS. 3a, b. This will be discussed further below.

The embodiment according to FIG. 2 corresponds essentially to the embodiment according to FIG. 1 with regard to the upper frame part 26 and the front frame part 3o. One difference, however, is that the lower frame part 34, 44 is a single connected part, because the two Side parts are united behind the rear wheel by a web part connecting them. This construction gives the frame greater rigidity and allows, instead of ₂ joints 42 with ball bearings, a single joint with a plastic bushing according to FIG. 3a to be used. In addition, the longer length of the rear part 44 of the lower frame part 34 compared to FIG. 1 leads to a greater drive torque in the movement phase where the weight rests on the saddle.

At its front end, the lower frame part 34 is extended beyond the joint 38 and bent downward. The footrests 60 are attached there in this embodiment. Compared to FIG. 1, this also includes an improvement in the lever transmission effective when driving, as in the arrangement of the bearing of the driving sprocket 20 in front of the joint 38, as shown in FIG. 2.

In a practical embodiment with 26-inch wheels, the vehicle according to FIG. 2 has the following dimensions: the rear part 44 of the lower frame part 34 is 38 cm, the cranks 48 are 17 cm, the connecting rods 52 are 46 cm and the other frame parts as long as indicated above for Fig. 1. The kink labeled α

und das Lagergehäuse 64. Die Streben B₁, B₂ sind durch Schrauben 7₀, welche sich durch Löcher in den Streben B₁, B₂ erstrecken und in eine mittlere Gewindebohrung im Bolzen 68 eingeschraubt sind, fest mit diesem verbunden.

and the bearing housing 64. The struts B _1, B ₂ are connected by bolts 7. _0, which is fixedly connected through holes in the struts B _1, B ₂ extend and are screwed into a central threaded bore in the bolt 68 thereto.

The lever mechanism formed by the articulated frame, the cranks 48 and the connecting rods 52 has two dead positions which must be overcome during each revolution of the chain wheel 2o during normal travel. This is not a problem if the rear sprocket 22 is non-rotatably connected to the rear wheel 12, but requires special precautions if it is desired to do so while driving, e.g. downhill to stop the up and down movement of the saddle, but continue to roll with the vehicle. Below are two possible solutions to this problem using F'ig. 4 explained. Fig. 2 then shows yet another proposal.

To ensure on the one hand the overcoming of the dead positions, on the other hand to stop the movements of the saddle, the footrests and the handlebars while driving, the embodiment according to FIG. 4 uses a friction clutch 76 and 78 consisting of two interacting friction disks, which during normal driving the drag torque from the hub of the rear wheel 12, designated 72, of which only spokes 74 are indicated in FIG. 4, to the chain wheel 22 - in a vehicle with an open gear shift, the chain wheel 22 is replaced by a block of, for example, 3 or 5 differently sized chain wheels -

The friction between the two friction disks 78 and 78 need not be great in order to overcome the above-mentioned dead positions. 78 inside then against other slip when the rider so desires and for this purpose shifts his weight opposite to the movement phase of the saddle and the pedals, for example in a phase where he should actually let his weight act on the saddle, the footrests are loaded.

A further alternative embodiment of the invention can be explained with reference to FIG. 4. Instead of a slipping clutch that is set to a specific maximum torque, a releasable clutch can also be used. For this purpose it can be provided that the pressure on the friction disks 76, 78 can be changed while driving, for example by firmly connecting the nut 84 to a lever 85 on which a Bowden cable to be actuated by the driver engages. The pulling wire of the Bowden cable acts in the loosening direction of rotation on the lever 85 and the nut 84, while in the opposite direction of rotation, i.e. in the direction of greater pretensioning of the plate spring 81, another clamped between the lever 85 or the nut 84 on the one hand and the rear frame part 34 on the other hand Spring 83 acts. The bias of the spring 83 is adjusted so that the clutch 76, 78 never slips regardless of whether the driver shifts his weight correctly or incorrectly. Only when the driver turns the nut 84 against the action of the spring 83 in the release direction by means of the Bowden cable and the lever 85 can the friction disks 76, 78 slide against each other so that the saddle stops moving up and down while driving. When using a strong releasable clutch, instead of a sprocket with a freewheel that is firmly seated on the wheel hub, a simple sprocket that rotates on the hub can be used.

2 contains a normal freewheel hub with coaster brake. The hub can optionally also include a three-speed gearbox. Alternatively, a normal freewheel hub without coaster brake with or without gear shift of any design can be used. Since normal freewheel hubs only develop a minimal drag torque, which is not sufficient to overcome the aforementioned dead positions, FIG. 2 shows a construction which solves the problem of dead positions in a different way. This is based on the fact that the distance between two specific points on the one hand on the rear frame part 32 and on the other hand on the connecting rod 52 is small in the dead position in which the saddle is in its highest position and is large in that dead position. in which the saddle has the lowest position. If, under these conditions, a rod designated by 86 in FIG. 2 is attached to the rear frame part 32 in an articulated manner and is guided, for example, by means of a roller 88 mounted on the upper frame part 26 in such a way that it at least in the uppermost position of the seat extends forward over the connecting rod 52 extends beyond, there is the possibility to clamp two tension springs 9 ₀ , 92 in such a way between the rod 86 and the connecting rod 52 that, for example, the spring 92 is strongly tensioned and at the same time the spring 9o is relaxed when the saddle is in its highest position is located, on the other hand, the spring 9o is under strong tension and the spring 92 is relieved, while the saddle occupies the lowest position. In this construction, one of the two springs then ensures that the connecting rod 52 is moved out of the dead position again.

.Practically the same result can also be achieved with just a single spring, which assumes approximately a middle position between the two springs 9o and 92 and is then tensioned both when the saddle moves to its highest position and when it sinks to its lowest position

.

It is understood that there is a great deal of freedom in the design of the individual frame parts, the joints and the rear wheel hub. For the sake of simplicity, the frame parts are shown and described essentially as straight steel tubes. As with bicycles, curved shapes, fairings, etc. are of course also possible. Dimensional deviations from the dimensions mentioned above bring with them certain changes in relative movements, speeds and accelerations, which, however, do not affect the basic functionality within a relatively wide range. After some dimensions of the frame have been determined, one can find by moving the hinge points, e.g. using clamps, as described in connection with Fig. 1, each very quickly the optimal position of the joints, at which the effort when driving is the least and / or the oscillating up and down with its alternating accelerations is most harmonious in series production the Kiemmschelier are replaced by welded joint parts, such as shown in Fig. 3 a. An essentially U-shaped, elastic bracket is provided as the lamp holder, which is attached directly behind the position of the lent rod with its one leg to part 26 and below the other leg to part 30.

Claims (11)

1. Bicycle-like two-wheeled vehicle with chain drive to the rear wheel, a saddle and a front fork rotatably mounted on the frame and connected to a handlebar, characterized in that the frame consists of four articulated parts (26, 3 ₀ , 32, 34), one of which the upper frame part (26) the saddle (18), the front frame part (3o) the front wheel fork (14) and the lower frame part (34) the rear wheel (12) and the driving sprocket (20) of the chain drive (2 ₀ , 22, 24), footrests (6 ₀ ) are attached to the front or lower frame part (3o; 34) and between the upper frame part (26) and a crank (48) non-rotatably connected to the driving sprocket (20), a connecting rod (articulated on both sides) 52) is arranged. 2. Vehicle according to claim 1, characterized in that axially on both sides of the bearing (46) of the driving sprocket (20) in a parallel arrangement each have a crank (48) and a connecting rod (52) are attached. 3. Vehicle according to claim 1 or 2, characterized in that the lower frame part (34) consists in one piece of two at the rear end connected by a web parallel struts, between which the rear wheel (12) is guided. 4, vehicle according to one of claims 1 to 3, characterized in that the joint (42) between the rear and the lower frame part (32, 34) is located radially outside the rear wheel (12).

6. Vehicle according to one of claims 1 to characterized in that the bearing (46) of the driving chain chain (20) in front of the joint (38) between the vcrderen and the lower frame part (30, 34) is arranged on the lower frame part (34) . 7. Vehicle according to one of claims 1 to 6, characterized in that the lower frame part (34) behind the rear wheel axle (40) is bent or angled upward by approximately lo to 60 °. 8. Vehicle according to one of claims 1 to characterized in that in combination with a freewheel in the drive connection (25, 23, 73) between the driven sprocket (22) of the chain drive (2 ₀ , 22, 24) and the hub (72 ) of the Hinyerrad (12) a non-positive clutch (76, 78) is arranged in a parallel arrangement to the freewheel, which is designed as a slip clutch or as an arbitrarily releasable clutch. 9. Vehicle according to one of claims 1 to 7, characterized in that in combination with a freewheel in the drive connection (25, 23, 73) between the driven sprocket (22) and the hub (72) of the rear wheel (12) on the connecting rod (52) acts on a spring force (90, 92) which the connecting rod (52) tends to move from the positions parallel to the crank (48). 1 ₀ . Vehicle according to one of claims 1 to 9 in use as a home trainer, characterized in that instead of the rear wheel (12) there is a flywheel, the axis of which is mounted in a horizontal position in a stable tripod, and the front frame part (30) is supported on the floor by a wheel (lo) or by a guide on the tripod.

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