WO1992007752A1

WO1992007752A1 - An improved crank-pedal unit

Info

Publication number: WO1992007752A1
Application number: PCT/IT1991/000088
Authority: WO
Inventors: Cesare Albanese
Original assignee: Cesare Albanese
Priority date: 1990-10-24
Filing date: 1991-10-23
Publication date: 1992-05-14
Also published as: AU8728991A; IT9048406A1; IT1242156B; IT9048406A0

Abstract

The invention relates to a crank (1)-pedal (3) unit of a bicycle having a frame (4) and a system for the transmission of the movement of the pedal stroke, eventually with a chain, gear wheels and various fittings, wherein the improvement consists in providing a first toothed wheel or sprocket (6), arranged fixed with the frame (4) in proximity to the axis (5) of rotation of the crank (1), a second sprocket (7), arranged at the free end of the crank (1) opposite that for pivoting the crank itself to the frame (4), rotatably integral with the pedal (3), so as to rotate with respect to the crank (1), and mechanical transmission means (11) between said first (6) and second (7) sprocket; the ratio between said sprockets (6, 7) being 1:1 and the foot of the cyclist being integral with the pedal (3) in such a way that the axis (8) of the pedal (3) is hooked to the shoe under the sole in front and near the heel.

Description

AN IMPROVED CRANK-PEDAL UNIT

The present invention relates to an improved crank-pedal unit. More particularly, the invention relates to a mechanical unit so structured as to allow the best utilization of the work of the calf during the pedal stroke.

At the present day, one is more and more in pursuit of solutions that allow the work to be best mechanically utilized of the greatest possible number of muscles of an athlete.

The studies and the applications are directed to both the muscular development of the athlete and the improvement of mechanical means in order to exploit the muscular masses developed with the training at the best.

In the classic pedal stroke that is effected with actual bicycles, in which the work on the pedal is effected with the front portion of the foot (the tip), the calf, which also is potentially able to do a work, is utilized to transmit the thrust of glutei and of quadricepses and possibly to enlarge the diameter of the pedal stroke.

If one was able to mechanically exploit the thrust of calves also, the benefits in terms of the efficiency would be decisely considerable.

In order to achieve such results, the Applicant has thought of modifying the crank-pedal unit such that, during the pedal stroke, the pedal maintains an orientation constant with respect to the bicycle frame whereby, the foot of the cyclist being rendered integral with the pedal itself, in the front stroke of the crank the action of the calf cooperates with the quadriceps for the opening of the angle between the tibia and the foot, for about 45-65 degrees.

These results are achieved, according to the invention, by arranging a pair of toothed wheels or sprockets in the ratio of 1:1, connected by a chain, such that the first sprocket is stationary with respect to the frame of the bicycle and the second sprocket, fixed with the pedal, rotates integrally with the same. It is therefore the specific object of the present invention a crank-pedal unit of a bicycle having a frame and a system for transmitting the movement of the pedal stroke possibly with a chain, gears and various fittings, such as the gearbox, etc., in which the improvement consists in providing^" a first sprocket, arranged fixed with the frame in proximity to the axis of rotation of the crank, a second sprocket, arranged at the free end of the crank opposite to that for pivoting the crank itself on the frame, rotatably integral with the pedal, so as to rotate with respect to the crank, and mechanical transmission means between said first and second sprocket; the ratio between said sprockets being 1:1 and the foot of a cyclist being integral with the pedal such that the pedal is hooked to the shoe under the front sole in front and near the heel.

According to the invention, said first sprocket is arranged fixed to the frame and coaxial with respect to the axis of rotation of the crank and with the possible crown gear for transmitting the movement.

In a preferred embodiment of the crank-pedal unit according to the invention, said first sprocket is arranged fixed on the frame with its axis placed parallelly and inferiorly with respect to the axis of rotation of the crank, a member being in this case provided for tightening the transmission mechanical means, for instance a chain or the like, between the two sprockets.

In particular, said means for tightening the mechanical transmission means can be made up of two arms, in the shape of a X or scissors pliers, pivoted on a plate coupled with the frame and rotatable about the axis of the first sprocket, said two arms being, each one in the portion in contact with a branch of the mechanical transmission means, drilled, and in the shape of a "C" to allow the passage of the branch of the mechanical transmission means.

Said plate can be provided with a "L" lug to maintain the chain coupled with the sprocket fixed with the frame. Analogously, also the crank can have an "L" lug with the same function at its pedal end.

In a preferred embodiment of the crank-pedal unit according to the invention, said mechanical transmission means between said first and second sprocket are made up of a third sprocket, which engages with said first and second sprocket, and is rotatably idle beared by two arms having each an extremity arranged upon the rotation axis of said third sprocket and the other upon the axis of rotation, respectively of said first and second sprocket.

Further, again according to this embodiment, said first sprocket is endowed with a stationary or adjustable lug connected with the frame.

Further, according to the invention the foot is rendered integral with the pedal by means of a proper shoe: a preferably conical pivot, provided on the pedal, couples with a crook hook which is part of the shoe and arranged under the sole, in front of the heel.

The present invention will be now disclosed according to its preferred embodiments with particular reference to the figures of the annexed drawings in which:

Figure 1 is a first right side view of the right crank according to the invention; Figure 2 is a second left side view of the same right crank according to the invention; Figure 3 is a section view along the line III- III of Figure 1;

Figure 4 is a side view, from the rear of the bicycle, of a second embodiment of the left crank of an unit according to the invention;

Figure 5 is a section view along the line V-V of Figure 4;

Figure 6 is a side view of the pedal according to the invention; Figure 7 is a bottom view, partially sectioned along line VII-VTI of Figure 6, of the pedal of Figure 8, and

Figure 8 is a section view along the line VIII-VIII of figure 6. With reference now to the figures 1, 2, 3 of the drawings, one can observe a usual crank 1, the crown gear 2 of the bicycle and the (right) pedal 3.

The crown 2 and the crank 1 are pivoted on the frame 4 of the bicycle on the same rotation axis 5. In the filed figures the first embodiment of the crank according to the invention is shown that provides two sprockets 6 and 7, with a gear ratio of 1:1, arranged the one (6) in correspondence with the crown gear 2 and the other (7) in correspondence with the pedal 3.

In particular, the sprocket 7 is pivoted in 8 on the crank 1, integrally rotatable with the pedal 3.

On the contrary, the sprocket 6 is fixed on the frame 4 upon an axis 9 parallel to the axis 5 of rotation of the crank 1 and crown gear 2, but displaced downwards.

In reality, as already mentioned, in an embodiment of the crank according to the invention, said axis 9 could coincide with the axis 5, it being not necessary, in this case, to provide the chain tightener

10, which will be described in the following. However, with this solution (axes 5 and 9 coinciding), the work usefully done by the calf is smaller, indeed it cooperates with the quadriceps for a restricted span of the angle tibia-foot, for about 45°. Proceeding now in the disclosure of the embodiment represented in the figures, a chain 11 is arranged between the sprockets 6 and 7.

Obviously, by virtue of the non-coincidence of the two parallel axes 5 and 9, the chain 11 will be thightened when the crank 1 is near its top dead centre, whereas during the forward stroke said chain will be loose in that the distance between the axes of the two sprockets 9 and 8 goes decreasing (the fixed distance that gives the radius of rotation of the pedal is obviously that between the axis 5 and the axis 8, that is to say always the length of the crank). Indeed from the maximum distance, with the crank at the top dead centre, one arrives at the minimum one at the bottom dead centre with a play, for each one of the two branches of the chain equal to two times the distance 5.9.

In order to be able to take up this excess of length of the chain, totally 4 times the distance 5.9, the aforementioned chain tightener 10 is provided (see in particular Figures 2 and 3) which is beared by a plate 12 rotatably pivoted on the same axis 9 of the fixed sprocket 6.

The chain tightener 10 is pivoted on said plate in 13 and is made up of two arms 10' and 10" that go to realize an X, or scissors.

The two arms 10* and 10" of the chain tightener 10, in the portion in contact with the chain 11, are hollow and in the end portion, where they encounter the first sprocket (6), in the shape of a "C" to make the said chain (11) to slide in them, guide and support the same as shown with the illustrative cutout (21) in Figure 1.

In this way, the plate 12 having the pivot 13 being part of the chain tightener 10 also, and being pivoted on the axis 9, during the rotation of the crank 1, the distance between the axis 8 and the axis 13 varies, modifying the angle of span of the two members of the chain tightener 10 which, sliding, on the washers 19, maintain the loose branch of the chain 10 always in a correct position. Indeed the structure of the chain tighteners

10, as disclosed, is such as to act conveniently on the side or on both sides of the chain and, moreover, without subjecting it to load, to avoid an unutilizeable friction increase. Indeed, it is to be considered that a chain tightener based upon elastic members would subject the loose portion of the chain also to a load.

The plate 12 is endowed with an "L" lug 14, which can be provided also at the free end of the crank (1) to prevent the chain 11 from getting out the sprocket 6 and the sprocket 7 respectively.

As precedently said in the introductory part, to obtain the desired effect of utilization of the work of the calf it is necessary that the projection 15 of the pin 8 of the pedal goes to found itself under the sole immediately in front of the heel of the shoe, and not, as usually happens, under the tip of the same.

To this end, the pedal 3 (see the detail in Figures 6, 7 and 8) provides a conic pin 15 that couples with a hook 16 realized integral with the shoe 17, lower than the same, in correspondence to the heel 18. As the force of the muscles of the heel is considerable, a lug 22 has been also provided, still integral with the shoe, in front of the heel, that goes to insert itself under the pin 15. In this way, the coupling foot, shoe 16-17-18-

22 and pedal 3-15 is ensured to obtain the maximum efficiency and, moreover, the disengagement of the foot from the pedal is quite easy through a simple rotation outwards of the tip of the foot itself.

In the embodiment represented in Figures 4 and 5, wherein the parts coinciding with those of the other figures are indicated with the same reference numerals, the transmission between the sprockets 6 and- 7 is obtained by means of the interposition of a third sprocket 23. Whilst the two sprockets 6 and 7 will have the same number of teeth always, the third sprocket 23 can also have a different number of teeth, without so modifying the transmission between the sprockets 6 and 7. The sprocket 23 is misaligned with respect to the sprockets 6 and 7 and is supported by means of two arms 24 and 25, respectively journaled upon the axes of the sprockets 6 and 7 themselves.

The sprocket 7 has its rotation axis 26 misaligned with respect to the axis 8 of the pedal, by an amount to be established at the moment of the manufacture design.

Below the sprocket 6 a lug 28 is provided, connected with the frame 4 of the bicycle, in a stationary or in an adjustable way. Its adjustableness can take place once for all or at the will of the cyclist eventually as a consequence of an attitude change during the pedal stroke, for instance from sitting to standing of the cyclist. The present u.Ttion has been disclosed ^**?ith specific reference to some its preferred embodiments, but it is to be understood that variations and/or modifications can be made by those skilled in the art, without so departing from the relevant scope of protection.

Claims

CLAIMS:

1. A crank-pedal unit of a bicycle having a frame and a system for transmitting the movement of the pedal stroke eventually with a chain, gear wheels and various fittings, such as a gearbox, etc., characterized in that it provides a first sprocket, arranged fixed with the frame in proximity to the axis of rotation of the crank, a second sprocket, arranged at the free end of the crank opposite that for pivoting the crank itself to the frame, rotateably integral with the pedal, so as to rotate with respect to the crank, and mechanical transmission means between said first and second sprockets; the ratio between said sprockets being 1:1 and the foot of the cyclist being integral with the pedal in such a way that the axis of the pedal is hooked to the shoe under the sole in front and near the heel.

2. The crank-pedal unit according to Claim 1, characterized in that said first sprocket is arranged fixed to the frame and coaxial with respect to the axis of rotation of the crank and to the eventual transmission crown gear.

3. The crank-pedal unit according to Claim 1, characterized in that said first sprocket is arranged fixed on the frame with its axis arranged parallelly and inferiorly with respect to the axis of rotation of the crank, a member being provided for tightening the mechanical transmission means between the two sprockets.

4. The crank-pedal unit according to Claim 3, characterized in that said mechanical transmission means are made up of two arms, in the shape of a X or of scissors, pivoted on a plate coupled to the frame and rotateable about the axis of the first sprocket, said two arms being each one, in the portion in contact with a branch of the transmission mechanical means, drilled and in the shape of a "C" to allow the passage of the branch of the transmission mechanical means.

5. The crank-pedal unit according to Claim 4, characterized in that said plate is endowed with an "L" lug for maintaining the chain coupled with the sprocket fixed to the frame.

6. The crank-pedal unit according to Claim 4 or 5, characterized in that said crank is provided with an "L" lug for maintaining the chain coupled with the sprocket fixed with the pedal.

7. The crank-pedal unit according to anyone of the preceding claims, characterized in that the foot is rendered integral with the pedal by means of a proper shoe.

8. The crank-pedal unit according to Claim 1, characterized in that said mechanical transmission means between said first and second sprocket are made up of a third sprocket, arranged idle between them.

9. The crank-pedal unit according to Claim 8, characterized in that said third sprocket is supported by two pairs of arms, each one having an extremity in correspondence to the axis of rotation of the third sprocket and the other extremity, respectively, in correspondence to the axis of rotation of the first or of the second sprocket.

10. The crank-pedal unit according to Claims 8 or 9, characterized in that a lug, coupled to the frame, is provided upon said first sprocket.

11. The crank-pedal unit according to Claim 10, characterized in that said lug is adjustable in the stage of trimming the bicycles.

12. The crank-pedal unit according to Claim 10, characterized in that said lug is adjustable during the pedal stroke.

13. The crank-pedal unit according to Claims 8 to 11, characterized in that said second sprocket is misaligned with respect to the axis of the pedal, the misalignement being adjustable.

14. The crank-pedal unit according to Claim 8, characterized in that a preferably single pin is provided, on the pedal, which couples with a crook hook which is portion of the shoe and arranged under the sole, in front of the heel.

15. The crank-pedal unit according to anyone of the preceding claims, substantially as illustrated and disclosed.