Hub with mechanism to permit backwards movement without pedal movement
A control mechanism for decoupling a drive ratchet on a bicycle hub makes it possible to push the bicycle backwards while the foot pedals of the pedal crank drive remain still. These functions can be applied to folding bicycles, in which pedal movements are harmful when in their folded up state. The control mechanism includes a controlling sleeve coupled to the drive ratchet, which is indirectly connected by means of a frictional device to the unmoving hub axle.
1. A bicycle drive hub for crank operated vehicles wherein the drive hub comprises:
a hub axle;
a hub shell rotatably mounted about the hub axle;
a driver mounted about the hub axle;
a freewheel in a torque path in the drive hub between the driver and the hub shell, wherein backwards rotational movement of the hub shell relative to the crank operated vehicle causes the freewheel to become disengaged, so that no torque is transferred to the torque path; and
a control mechanism including a control sleeve engaged with a friction spring, whereby in all the operating states of the drive hub, a forwards rotation of the driver causes the control sleeve to permit engagement of the freewheel in the torque path.
2. The drive hub of claim 1 , wherein the friction spring is positioned between the control sleeve and a larger hub cone, wherein the larger hub cone is fixed to the hub axle.
3. The drive hub of claim 1 , wherein the freewheel includes a direct gear pawl which pivots radially against the force of a spring, and wherein the direct gear pawl is positioned to engage direct gear teeth.
4. The drive hub of claim 3 , wherein the control sleeve prevents the direct gear pawl of the freewheel from engaging the direct gear teeth when the hub shell rotates backwards.
5. The drive hub of claim 4 , whereby the direct gear pawl of the freewheel is carried on a pawl carrier and is prevented from engaging the direct gear teeth when the pawl carrier rotates relative to the control sleeve such that the direct gear pawls are pushed radially to the inside by the control sleeve and are thereby taken out of operation to permit the hub shell to freely rotate backwards with the hub shell disengaged from the direct gear pawls when the hub shell rotates backwards.
6. The drive hub of claim 3 , wherein the control sleeve has circumferential backlash with a pawl carrier of the direct gear pawl, and when the circumferential backlash is overcome the direct gear pawl is brought out of engagement with the direct gear teeth.
7. The drive hub of claim 1 , wherein the friction spring includes a ring-shaped bent segment and a segment which is bent to the side to form a spring projection, whereby the spring projection resides in a spring projection receptacle formed in the control sleeve, in order to rotate together with the control sleeve;
whereby the ring-shaped bent segment engages with a friction spring receptacle on a larger hub cone positioned opposite to the driver and fixed to the hub axle, in order to connect with the larger hub cone.
8. The drive hub of claim 1 wherein the drive hub is a gear hub including a planetary gear mechanism including two torque paths with different transmission ratios, which is switched depending on the rotation speed of the driver between a torque path with a direct gear and a torque path with an overdrive gear.
9. The drive hub of claim 8 wherein the planetary gear mechanism includes the driver and a planet gear carrier formed as one part.
10. The drive hub of claim 8 wherein the planetary gear mechanism includes a ring gear positioned in the torque path with the overdrive gear, the ring gear having an axial extension and the axial extension includes a ring gear axial extension, on which a pawl control cam for the automatic switching of an overdrive gear pawl is positioned.
11. The drive hub of claim 8 wherein the freewheel includes a direct gear pawl and direct gear teeth, the freewheel positioned in the torque path between the planetary gear mechanism and the hub shell.