JPS6157232B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to brake actuation means for pedal-powered vehicles, such as bicycles. Although the present invention is applicable to pedal vehicles of two or more wheels, such as tricycles, the present invention will be described in detail below with respect to the most common type of vehicle, a bicycle. However, this does not mean that the present invention is exclusively applied to bicycles.

Bicycle brakes are roughly divided into two types.
That is, there are two types: a manual brake and a foot brake. The most common are foot brakes, known as "coaster" brakes or backpedal brakes. The braking mechanism of conventional coaster brakes was housed within the hub of the bicycle's rear wheel, and the actuation force was transmitted by the chain itself used to propel the bicycle. The means for activating such coaster brakes is pedal reversal or backpedaling, from which a counter-torque is transmitted to the rear wheel via tension in the lower strand of the chain. The braking mechanism of a manual brake may be of a clamping type that applies pressure to the opposing flat sides of the wheel rim, or of a drum-shew brake or disc brake type housed within the wheel hub. Either. Other poorly performing braking mechanisms have also been used with manual brakes in the past. For example, a simple so-called "spoon" device that pushes the outside of the tire,
A so-called "stirrup" device was also used, which applied pressure to the inner surface of the rim.

Both manual brakes and coaster brakes have drawbacks. The main disadvantage of manual brakes is the hand force required to apply the brakes. This hinders steering wheel control for riding a bicycle. Particularly when one hand is off the handlebar, hand movements are concentrated on applying the brakes, making it extremely difficult to steer the bicycle.

A major drawback of conventional coaster brakes is that if the main drive chain is damaged or slipped in an accident, the brake becomes inoperable. However, this does not apply to bicycles which are equipped with a switching mechanism, such as a transmission gear, such that the lower strand of the drive chain is not used at all for transmitting traction forces.

The following proposals have already been made several times to solve the above problems. That is, the pedal crankshaft is combined with a one-way clutch that applies the backpedaling force first to a lever and then to a braking mechanism, which may be a conventional manual brake.

One representative group of such proposals uses a ratchet and pawl mechanism to create the necessary one-way clutch. However, adopting such a mechanism requires a change in the design of the pedal crankshaft. This is because the ratchet or pawl must be secured to or incorporated into the crankshaft. moreover,
If such a mechanism is employed, considerable movement will occur before full engagement or disengagement is achieved. Furthermore, because of the angular relative position of the ratchet and the pawl or pawls, the brake can only be applied at certain angular positions of the crankshaft. Certain braking mechanisms of this type can jam themselves, which is not only an inconvenience, but at worst can be very dangerous.

Such troubles could be overcome by using a spring type one-way clutch. For example, U.S. Patent No. 1488714 (dated April 1, 1924), Italian Patent No. 300578 (dated September 13, 1932), Italian Patent No.
29/29) and U.S. Patent No. 2940563 (June 1960)
A spring-type one-way clutch for this purpose is disclosed in the patent application, dated May 14, 1993. However, none of the above patents shows anything that can be applied to coaster brakes for trendy 5-speed and 10-speed bicycles equipped with derailleur tippe gears, which are currently gaining attention in the market. Not yet.

Most bicycles with derailers or similar transmission gears have an outside diameter of 1.5 inches (approximately 38.1 mm) and a length of
Manufactured with a 2.5 inch pedal crankshaft housing. A brake actuation device that is acceptable to bicycle manufacturers must be extremely simple and robust in construction. And drag when the brakes are in the "off" state must be kept to a minimum. Furthermore, there should be no major changes to the crankshaft housings of the sizes described above, and the use of substantially similar, if not identical, pedal crankshafts should be acceptable. Furthermore, in the event of a sudden stop, the load, i.e. 200 pounds (approx.
It is necessary to be able to withstand conditions that can generate treading forces of up to 100 kg. One of the advantages of coaster-type brakes is that very large braking forces can be generated by the rider himself, but on the other hand this means that the stresses generated and applied to the actuation mechanism cannot be reached without other means. Unless measures are taken, this will cause problems that will become extremely large. That is, when a passenger applies his or her entire weight to one of the pedals in an attempt to apply sudden braking, the stress generated is extremely large.

In the above-mentioned patents, the clutch mechanism is arranged between the crank housing and one of the pedal cranks (for example, Italian Patent No. 456997)
(as in US Pat. No. 1,488,714) or inside the pedal crank arm (as in US Pat. No. 1,488,714). In either case, the space available is limited and therefore a non-standard crankshaft and/or crank arm is required. Furthermore, this mechanism is prone to dust accumulation and is susceptible to mechanical damage. Therefore, if it were not for the fact that in many cases the space between the crankshaft and the housing is extremely limited, it would be better to accommodate it inside the crankhousing itself (for example, as in Italian Patent No. 300,578) case) would be preferable. However, in reality, it is difficult to accommodate or incorporate the mechanism disclosed in the Italian patent specification without considerably weakening the strength of the housing itself by cutting or drilling holes in the housing. or impossible. Since the crankshaft housing is an integral part of the bicycle frame, e.g.
Preferably, no design changes to this component are required, as in the case of No. 2940563.

Therefore, an object of the present invention is to provide a coaster type brake in which the brake actuation force is obtained from the pedal crankshaft by coupling the clutch, which can be configured to withstand sudden braking force, and which can be configured to withstand sudden braking force, and which is compatible with the most common conventional pedal type. To provide a coaster brake that can be stored in a crankshaft housing, is easy and inexpensive to manufacture and assemble, and minimizes drag during normal operation of a bicycle.

Thus, the present invention provides an improved brake actuation system for applying the brakes of a pedal-actuated vehicle. The improved brake actuation device according to the present invention includes one brake actuation lever that projects through an opening in the pedal crankshaft housing of the pedal vehicle. The lever is connected to a friction coupling concentrically surrounding the pedal crankshaft within the housing, the coupling consisting of two spring coils wrapped around the crankshaft with a light engagement. The direction of winding from the free end of each spring coil to the restrained end connected to the lever is the same as the direction of rotation of the crankshaft which causes forward motion of the vehicle. The two spring coils are constructed by winding a common wire, forming a loop that engages a lever at each restraining end.

According to a first feature of the invention, each spring coil consists of a first part and a second part, the first part being the winding closer to the lever and the second part being the winding farther from the lever. This is the winding part. The winding part in the second part is constructed by winding a wire having a smaller cross-sectional area than the wire constituting the winding part in the first part, and the crankshaft is normally connected to the winding part in the second part. It is wrapped around only by.

According to a second feature, said lever consists of a lever arm and a yoke engaging at least a part of the circumference of the crankshaft, and in the actuating surface of said lever said lever is connected to the pedal crankshaft. not having a dimension larger than the inner diameter of the housing, but sized so that when the yoke of the lever engages the crankshaft, the arm of the lever passes through an opening in the housing and projects beyond the outer surface of the housing; It is being

Such a configuration allows most conventional crankshaft housings to incorporate a durable clutch connection mechanism that can withstand heavy braking conditions, and which allows the clutch to be used during normal forward pedaling of the bicycle. The drag force applied to the pedal crankshaft is minimal.

According to yet another feature of the invention, the travel of the lever is limited by the size of the opening in the crankhousing so as to limit the strain applied to the brake and brake linkage. Damage to these components is thus prevented in the event of sudden braking.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments with reference to the drawings.

Turning first to the embodiment shown in FIGS. 1 and 2, the brake actuation device is housed between the pedal crankshaft 1 and the crankshaft housing 5 of the bicycle. The crankshaft is supported within the housing by a conventional ball race assembly 14. All of these components may be of conventional construction. However, a constricted crankshaft with a reduced diameter in the center is not suitable.
The central part of the crankshaft between both races must have a cylindrical outer surface 2 of the same diameter. The only difference from the conventional standard crankshaft housing is that a slot 8 is provided in the bottom of the housing. This slot will be described later.

The main components of the brake actuation device are the yoke 2
4a and a lever arm 4a, and a spring coil assembly consisting of two spring coils 3. The two spring coils 3 are connected to each other by a connecting loop 15, which engages in a correspondingly shaped groove 16 formed in one arm of the yoke 24a. Lever 4a
protrudes through the slot 8, and a perforated metal shield 6 placed over the lever arm serves to prevent dust from entering the housing through the slot 8 and to insert the loop 15 into the groove 16. It serves a dual purpose: to hold the

The structure of the spring coil assembly is shown in Figures 7 and 8.
It may be best understood with reference to the figures. That is, the inner portions (inside portions) of the two spring coils 3 and the loop 15 are formed from one continuous steel plate with a square cross section. The square cross section was chosen to provide maximum tensile strength with minimal high volume, but rectangular cross sections other than square can be used if space conditions require a coil that is more elongated than the cross section. It is. The outer portions (outer portions) 3a of the two coils are formed of wires having a smaller cross-sectional area than the inner portions. In the illustrated embodiment, the cross-sectional dimensions of the lines constituting this outer portion are half those of the lines constituting the inner portion. This dimensional difference allows for a substantial increase in the number of coil turns within the same width range compared to if wire of the same dimensions as the inner section were used throughout. . The inner diameter of the coil winding in the outer part is dimensioned such that the winding coil lightly hugs the surface 2 of the crankshaft.
On the other hand, the inner diameter of the coil winding in the inner portion is slightly larger than the outer diameter of the shaft so as to form a gap with the shaft surface 2 under normal conditions. The structure of this coil assembly will be discussed further below in connection with its operation.

As shown in FIG. 2 by an imaginary dashed-dotted line, the lever consisting of the yoke 24a and the arm 4a does not have any portion that exceeds the inner diameter of the crankshaft housing 5. The lever can therefore be inserted into the housing until the arm 4a retracts into the slot 8 without having to expand the slot 8 to accommodate the arm 4a. During assembly, the shield plate 6 is placed over the arm 4a extending through the loop of the spring assembly prior to insertion of the lever. After that, insert those three components into the housing 5 and place them next to the housing 4a.
fits into the slot 8, and the loop 15 fits into the groove 16.
so that it engages with After this, crankshaft 1
is passed through the spring coil and the ball race assembly 14 is assembled. between the coil and the bearing ball,
Or if a bearing ball cage is used,
A washer 7 may be provided to prevent contact between the coil and its ball cage.

To allow the use of longer lever arms, the shape of the lever may be such that the yoke 24b is offset relative to the arm 4b, as shown in FIG. According to the configuration shown in FIG. 3, the arm of the lever can be expanded without increasing the maximum dimension of the lever to the extent that it exceeds the inner diameter of the crankshaft housing 5, as can be understood from the imaginary dashed line in FIG. Can be made longer.

In the embodiment shown in FIG. 4, yoke 24c is constructed with an integral strap that surrounds the crankshaft. In this case, the lever arm 4 which can fit into the inner diameter of the crankshaft housing
The length of c is very limited. Therefore, arm 4
After installing c into the crankshaft housing,
It is preferable to attach a separate lever arm extension member 4d having a desired length to the protrusion of the arm 4c. In the illustrated example, the extension member 4d is connected to the arm 4c by a dovetail connection method. Of course, other connection methods may also be used.

Figure 5 shows a lever arm like 4a and a nipple N.
A typical connection method with a brake actuation cable C terminated in is shown. The lever is formed with a clevis, one arm of which is provided with a slot S, and when the nipple is inserted into the hole of the clevis, the cable passes through the slot S. can be introduced into the fork of the U-link.

FIG. 6 shows a typical method of connecting a lever arm such as 4b to a brake actuation rod R using a shackle K. In the case of this connection, the lever arm must protrude longer from the crankshaft housing in order to obtain the necessary clearance for the shaft.

9 to 12 respectively show various examples of application of the above-described brake actuating device to bicycles. 9th
In the illustrated case, the lever arm 4a of the lever as shown in FIG. 2 is connected to the cable 17. Cable 17 extends through a flexible outer jacket to a conventional pinch brake 19. Due to the direction of approach of the brake cable to the brake actuation device, brakes of the type normally used on women's bicycles with manual rear brakes are suitable in this case. Of course, this is just one example, and it is an advantage of the invention that the same brake assembly can be used for bicycles with and without crossbars.

In the case of FIG. 10, the clamping brake 20 is actuated by a direct tension connection. This connecting member may be a cable or a rod, for example a rod 21 attached to the lever arm 4b of a lever as shown in FIG. 3 (or to the arm extension 4d of a lever as shown in FIG. 4). In the case of FIG. 11, a drum brake 22 of known type is applied to the rear wheel hub of the bicycle and the braking force is transferred to the lever arm 4.
b (or 4d) via rods 23 and 30 and step-out lever 25 to the brake arm of the drum brake.

In the case of FIG. 12, a brake disc 26 is used on the rear wheel hub of the bicycle, and a brake scissor 27 is connected to said lever arm 4a by a cable 28 extending through a flexible outer sheath.
is activated.

Next, the operation of the above-described embodiment device will be explained. When the bicycle is pedaled in the normal forward direction, the crankshaft 1 rotates counterclockwise as viewed in FIG. As mentioned above, the outer part 3a of the spring coil lightly engages the surface 2 of the crankshaft, and since the rotation of the coil is restrained by the lever, this counterclockwise rotation of the crankshaft A reaction force is generated within the coil to unwind the coil, and as a result, the engagement force of the coil with the crankshaft is reduced, and the drag or drag force applied to the crankshaft is reduced. Since the coil portion 3a is a fairly thin wire, the initial drag is in any case mild. When the pedals are reversed, ie, backpedaled, the drag force on the coil is transferred to the brake rod or cable, creating a force that tends to wind up the coil. Therefore, the coil becomes tightly wound around the crankshaft 2, creating a strong feedback effect. As the force applied to the brake rod or cable increases,
The inner portion of the coil 3 also wraps around the crankshaft, further increasing the available braking force. When the coil is in frictional engagement with the crankshaft, the tensile force in the wire forming the coil decreases exponentially with distance from loop 15. Therefore,
The maximum tensile force generated in the wound wire of the outer part of the coil is always less than the maximum tensile force developed in the inner coil part. This makes it possible to significantly reduce the cross-sectional area of the outer coil portion. Due to the reduced cross-sectional area, the coil width required for a given number of turns is reduced and the drag on the crankshaft during normal forward pedaling is reduced, a dual benefit. At the same time, it becomes permissible to increase the cross-sectional area of the wire used in the inner part of the coil to an extent sufficient to withstand the tensile forces generated during sudden braking. Using standard size components and assuming worst-case conditions, the total tensile load that must be carried by both coils at the end adjacent loop 15 is approximately 5000 lbs.
The order will be kg). the coil wire
Just plain spring steel with a cross-sectional area of 0.110 inches square and heat treated to give it sufficient ultimate tensile strength can withstand such loads. . Only a small portion of this load will be transferred to the coil portion 3a. The actual rate of load transferred is determined by the coefficient of static friction between the coil assembly and the crankshaft. Even if the coefficient of static friction is less than 0.075, which is extremely unlikely, the proportion of the load applied to the coil portion 3a will be as follows, assuming that each inner portion of the coil has three turns:
It will be less than a quarter of its maximum tension. As a more likely value, if the coefficient of static friction were 0.150, a force less than 1/16 of the maximum tension would be applied to the coil portion 3a.

In order to support the applied tensile forces, the wire making up the coil portion 3a is preferably butt welded to the wire making up the remainder of the coil prior to winding and heat treatment of the coil.
However, other joining methods may be used, provided they provide the necessary load bearing capacity and are sufficiently reliable. Although the coil portion 3a is shown as having a square cross-section, it may also have a circular cross-section if the available space permits. Furthermore, although spring steel is exemplified above as a material for the spring coil, the elasticity required for this spring coil is actually extremely small. The tensile strength of the metal used is more important than its yield strength. This is because mild plastic deformation can be tolerated without causing clutch failure.

Of course, the yokes 24a, 24b, and 24c must have sufficient strength to withstand the loads applied to them by the coil assembly. Conventional bicycle braking systems may lack sufficient strength to withstand the forces applied through the lever arm during sudden braking. However, the front end 8a of the slot 8
Such forces can be limited by locating the forward end 8a at a point where it acts as a stopping surface for the lever arm before the strain on the brake coupling member and brake becomes excessive. can. Under normal conditions, if the stop surface 8a
If it is already working, you need to adjust the brakes immediately. This stop surface further prevents excessive force from being applied to the outer end of the lever arm. This is a particularly valuable feature when the lever arm extension 4d is used.

In the case of certain brakes, for example the 12th
If a disc brake such as that shown in the figures is to be activated, the large forces that can be easily generated by the brake actuation device of the invention are an advantage. This is because such disc brakes often require a greater actuation force than is easily generated by a normal handbrake actuation lever.

The embodiment of the invention described above has a diameter of approximately 1.5 inches (approx.
Suitable for use on bicycles with an outer diameter of 38.1 mm, a 2.5 inch long crankshaft housing, and a maximum crankshaft diameter of 13/16 inch. It is. These dimensions are standard dimensions; larger and smaller housings may be used. In the case of a housing whose inner diameter is smaller than the above standard dimensions, the presence of the groove 16 in the yoke, as in the embodiment described above, reduces the Z dimension (see Figure 3) and makes the yoke unsafe. The more vulnerable you become. In the embodiment shown in FIGS. 13 and 14, the loop 15a of the spring coil assembly is arranged around the base of the lever 4e. According to this configuration, the reaction force to the tensile force generated in the spring coil assembly when the brake is applied acts to move the yoke away from the crankshaft, and as in the case of each of the embodiments described above, the reaction force acts to move the yoke away from the crankshaft. It does not work so that the yoke is pulled. Therefore, in order to solve this problem, yoke 2
A side flange 31 is formed at 4e. This flange supports the first turn of each coil 3. Therefore, the tensile force of the coil generates a force that presses the yoke against the crankshaft surface 2. A shielding member 6b is integrally formed on the side flange 32, and the coil 3 is connected to the flange 31.
This prevents it from slipping off.

According to the configuration of this embodiment, the outer diameter is only 1
3/8 inch (approximately 34.9 mm), wall thickness approximately 2/32 inch (approximately
2.38 mm) and the crankshaft diameter is 13/16 inches (approximately 20.6 mm), making it possible to incorporate a brake actuation device strong enough to withstand the force of sudden braking into the crankshaft housing.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a bicycle crankshaft housing taken in the longitudinal direction of the housing and along the transverse direction of the bicycle, showing a first embodiment of a brake actuation device according to the present invention. FIG. 2 is a sectional view taken along line 2--2 in FIG. 1. FIG. 3 is a sectional view similar to FIG. 2, but some parts have been omitted for clarity, and shows a modification of the embodiment of FIGS. 1 and 2. FIG. 4 shows yet another modification similar to FIG. 3. 5 and 6 are partially detailed views showing the connections between the brake actuation device and the brake cable, and between the brake actuation device and the brake rod, respectively. FIG. 7 is a front view (with respect to the direction of travel of the bicycle) of the spring coil assembly shown in FIGS. 1 and 2; FIG. 8 is an end view of the spring coil assembly. 9 to 12 are schematic diagrams of bicycles showing examples in which the present invention is applied to various rear wheel brake mechanisms. FIG. 13 shows a variant of the invention suitable for use in cases where the clearance between the crankshaft and the crankshaft housing is particularly limited. FIG. 14 is a partial plan view showing the components of the brake actuation device of the present invention combined with the crankshaft of a bicycle. 1... Crankshaft, 5... Pedal crankshaft housing, 4a, 4b, 4c, 4e... Lever arm, 2
4a, 24b, 24c, 24e... Yoke of lever, 8... Opening of housing, 3, 3a... Spring coil assembly, 3... First coil part (inner part), 3a... Second coil part (outer part) ,8a
...End abutment surface (stop surface) of housing opening, 2...Crankshaft surface, 15...Loop, 4d...Removable lever arm extension member, 16...Groove provided in yoke, 31...Flange provided in yoke .

Claims (1)

Claims: 1. A device for actuating the brakes of a pedal-actuated vehicle, comprising a friction coupling and a friction coupling projecting through an opening in a pedal crankshaft housing of the vehicle and coupled to a brake actuation coupling member. a brake actuation lever connected within the housing with the friction coupling concentrically surrounding the pedal crankshaft within the housing, the friction coupling being lightly attached to the crankshaft. consisting of two coiled spring coils, the winding direction of each spring coil extending from a free end to a restraining end connected to the lever is the same as the direction of rotation of the crankshaft causing forward motion of the vehicle; The two spring coils are formed by winding a common wire in a loop shape at their restraining ends, and the loop-shaped portion is engaged with the actuation lever of the brake actuation device. , each spring coil has a first portion consisting of turns closer to the lever and a second portion consisting of turns farther from the lever.
, and the turns in the second part are wound with a wire having a smaller cross-sectional area than the wire constituting the turns in the first part,
A brake actuating device characterized in that the crankshaft is wound only by the number of turns of the second portion in a normal state. 2. The brake actuation device according to claim 1, wherein at least the first portion of both spring coils is made of a wire having a square cross section. 3. The torsional resistance of both spring coils causes the lever arm of the brake actuating lever to engage with the end abutment surface that limits the opening in the pedal crankshaft housing in response to a predetermined strain being applied to the lever arm of the brake actuating lever. The brake actuating device according to claim 1 or 2, characterized in that the brake actuating device has a size that allows the brake actuator to fit the brake actuating device. 4. The brake actuation lever includes a yoke that engages at least a portion of the circumferential surface of the crankshaft, and in the actuation surface of the lever, the lever does not have any dimension that exceeds the inner diameter of the pedal crankshaft housing, and the yoke Claim 1, wherein the arm of the lever is dimensioned to protrude through an opening in the housing and beyond the outer surface of the housing only when engaged with the crankshaft surface. The brake actuation device according to any one of items 1 to 3. 5. Claim 4, characterized in that the loop connecting the two spring coils engages with a groove provided in the end of the yoke, which is the leading end with respect to forward rotation of the crankshaft. Brake actuation device as described. 6. The brake actuation device according to claim 4 or 5, wherein the yoke of the brake actuation lever is biased in the direction of the tip with respect to the lever arm. 7. The brake actuation device according to claim 4, 5, or 6, wherein an extension member that is removable from the outside of the pedal crankshaft housing is attached to the lever arm. 8. The brake actuating device according to claim 7, wherein both ends of the yoke of the lever are connected by a strap that surrounds the crankshaft and is integrally formed with the yoke. 9 A patent characterized in that a loop connecting two spring coils passes around the lever arm, and the part of the coil near the loop overlies a flange extending from the yoke. A brake actuation device according to any one of claims 4 to 8. 10. A device for operating brakes of a pedal-operated vehicle, comprising a friction coupling;
a brake activation lever protruding through an opening in the vehicle pedal crankshaft housing and connected to the brake activation coupling member, the lever concentrically surrounding the pedal crankshaft within the housing; It is connected inside the housing with a friction coupling, the friction coupling consisting of two spring coils lightly wound around the crankshaft, with each spring coil winding progressing from a free end to a restraining end coupled to the lever. The direction of rotation is the same as the direction of rotation of the crankshaft which causes forward movement of the vehicle, and the two spring coils are formed by winding a common wire looped at their restraining ends. A brake actuating device for actuating the brakes of a pedal-operated vehicle in which the loop-shaped portion engages with the actuating lever, wherein each spring coil has a winding portion closer to the lever. and a second portion consisting of a winding portion farther from the lever, and the winding portion in the second portion constitutes a winding portion of the first portion. The brake actuating device is a pedal having one opening, which is a wire wound with a cross-sectional area smaller than that of the wire, and the crankshaft is normally wound only by the winding of the second part. CLAIMS 1. A pedal-operated vehicle having a brake, a pedal crank and a pedal crank housing, characterized in that the brake is integrated into the crank housing.