ACT-DRIVE
Revive the classical bicycle
and make easy your commuting
AN INVENTION WAS BORN
01
The chalenge
1. To be applicable on regular bicycles (OMA/OPAFIETS) elsewhere and particularly in the Netherland at reasonable price
2. To provide an acceptable selectable insertion effort level and to make easier our everyday city cycling.
3. To act automatically and steplessly at the most common situations in the city commuting like start, accelerate, moderate climbing and cruising
4. To achieve all above requirements in a pure mechanical way
5. To be reliable and easy to maintain
02
The solution
1. The ACT-drive is fixed to a standard (JIS/ISO) crank and can replace by easy the existing one without robber a bank.
2. Everybody is deciding which effort is personally comfortable by choosing one of the available 3 balance springs load levels: S (soft), M (medium) and L (load)
3. The automatic action is provided by the innovative balance mechanism.
4. There is no fancy electronics, hydraulics, batteries etc. - just pure mechanics ;)
5. Reliable construction with standard maintenance.
03
The construction
The ACT-drive mechanism consist of only 3 main parts - guiding base, chain wheel and springs. Its automatic and stepless action is achieved only mechanically.
In ACT-drive, the insertion effort level (transmission ratio) is determined not as a ratio between the teeth number on the sprockets (drive/driven), but as a lever arms ratio - crank to chain wheel radius in the active zone. The change is achieved by sliding the chain wheel in the guiding base slots. Yes, the transmission ratio of the real ACT-drive mechanism within the size of a regular 48 tooth chain wheel is not greater than 200%, but this is good enough to make easier our city commuting and safe our knees as a bonus.
THE PATENT
International and EU
ACT-drive received an international and EU patent. The general design is directed to the regular city bicycles (particularly in the Netherland), but could be adopted wherever applicable.
TECHNICAL DATA
Isometric drawing
GENIUS DESIGN
Simple but yet effective and easy to maintain.
The automatic cyclic transmission, according to the present invention, changes the gear ratio without changing the geometry of the driving gear wheel or the guiding base, but by offsetting the driving gear wheel relative to the center of rotation of the guiding base at optimum moment of the work cycle. The automatic cyclic transmission has a simple construction with few elements, which is making it easier for maintenance by keeping the weight low.
In an evenly unladen motion with an effort less than the trigger value determined by the pre-tensioning of the damper springs 3, the automatic cyclic transmission shall operate in a classic way like a circumferential chainwheel.
The change action is invoked when two factors are met - when the resistance transmitted by the chain overcome the trigger force of the damper springs 3 and when the tensile angle is less than 90° to the vector of action of the damper springs 3 and the guiding slides 4. Simply to say only when is needed - at start, accelerate, or climb.
The ACT-drive (automatic cyclic transmission) can replace without any processing the front chainwheel of most existing bicycles, applying to the corresponding standard coupling. The highest degree of compatibility has the classic city bicycles used in Netherland, Denmark and Germany equiped with tapped square axis bottom bracket. The rear hub can remain with the existing cartridge/derailleur/hub, which can be used to improve further the efficiency. On the rear axis can be also a standard drive with coaster brake or a freewheel one supported by a simple chain tensioner placed on the underside of the chain guard, which could further simplify and lighten the structure in general. In any case ACT-drive don't need ANY switching mechanism, cables or other means (e.g. fancy BT battery opperated), because act fully automatically based on the inovative mechanical construction.
