Latest News:

Lever drive "blade drive" now ready for manufacture! Incorporating continuously variable transmission. Complete drive including all gearing & braking in the same unit! Adaptable to suit most wheelchair models. Further details will be announced on this site as development continues.

LEVER DRIVE WHEELCHAIRS A BRIEF HISTORY.   

Since the early 1900's patents have been regularly filed for designs for this type of wheelchair transmission, yet very few have succeeded commercially.
Our research shows that nearly all the designs have the pivoting drive levers placed either side of the occupant then connected to each wheel independently. The levers being connected to the wheels in traditional ways such as: -

Directly to the wheel, or via:

Chains & sprockets.
Belts & pulleys.
Rod linkages.

See video

WHY ARE THEY NOT READILY AVAILABLE?

Unfortunately, traditional lever transmission methods have many disadvantages.

For example: -

1. Independent drive handles - one driving each wheel.

With the handles traditionally driving each side independently when pushing forwards, the occupant is constantly correcting the direction of the wheelchair & a smooth straight path is almost impossible or requires a great deal of concentration.
When travelling on a flat surface the occupant can power forwards, then coast while returning the handles for the next power stroke. Both handles must be pushed together with the same force & at the same speed to travel in a straight line. When ascending an incline the wheelchair coasting distance is greatly reduced & is eliminated on steeper inclines. This results in speeding up on the power stroke & slowing down when returning the levers, this is eliminated by using a push & pull driving system & a constant smooth ride can easily be acheived. Traditionally the power is only on the push stroke however, it is more biomechanically efficient to use the pull stroke. A larger & more efficient group muscles is used when pulling, the Jouleflow system allows these muscles to be used. To demonstrate the increased power of pulling. When seated, lift an object to chest level (pulling) & note the effort required, then lift above your head (pushing). You will find it much harder to lift above your head.
With independent handles one handed driving is impossible, as the wheelchair will simply travel in a circle.
If the handles are linked together then steering is lost.

Conclusion.

The power from both handles must be harnessed simultaneously before the drive to the wheels, without losing the ability to steer.
As one handle pushes forward the other is pulled, this gives a neutral effect on the occupant as one force on the left is counteracted with an equal & opposite force on the right. As power is constantly applied & there is no re-setting of the handles a smoother ride results - even on inclines. When stopped facing up an incline no rollback occurs & the occupant can remove their hands at any time without the levers moving backwards..
No turning force is exerted on the wheelchair as both driving forces are harnessed together before driving the wheels. One-handed propulsion is required without losing the ability to travel in a straight line, either hand can be used.

2. No gearing. 

Even a modest incline significantly increases the amount of power required to push the levers to propel the wheelchair. This leads to occupant fatigue & a decrease in control, resulting in the wheelchair being unable to follow a reasonable straight line. The fixed gear can be set to a low ratio that will help on inclines but will become unreasonably slow under flat conditions. Different levels of occupant fitness, strength & mobility will require different gear ratios. A common ratio will never be ideal as the circumstances are constantly changing - inclines - terrain etc..

Conclusion.

Several different gears are required to suit the occupants circumstances & the conditions.

3. Turning efficiency.

With many of the traditional style wheelchair transmissions various types of turning are possible.

Pushing one lever harder than the other can make slight directional changes. Unfortunately this results in the occupant deliberately not applying their full force to both levers all the time & therefore inefficient.

Pushing one lever only & slightly applying the brake to the opposite side can make a more pronounced change in direction. This is even more inefficient as only half of the available power (one lever) is transmitted to only one wheel.

Pushing one lever & applying the brake fully gives the tightest turning circle. Once again half of the available power is being used.

A combination of these actions has to be used all the time in order to travel in the required direction. To be fully efficient both handles need to be used all the time & no loss of power must be taken up by the brakes.

Most lever transmission systems do not allow the wheelchair to turn on its own axis unless both hand rims are used. Also, most other systems do not allow either wheel to be rotated backwards with the drive engaged without the lever rotating backwards.

Conclusion. 

The Jouleflow system allows both handles to be constantly used regardless of the direction required. There must be no power lost by the brakes when turning unless both brakes are applied for stopping. When attempting the tightest turns the wheelchair must be more responsive typically turning on its axis without having to use both hand rims.

This system with its unique drive mechanism allows the user to have the transmission enaged most of the time when in confined spaces . If facing an obstruction the occupant can simply reverse one wheel via the handrim & the wheelchair will spin on its own axis. This is achieved because the transmission automatically rotates the opposite wheel forwards without the handles moving & can eliminate the need to reverse.

4. Exposure to dirt. 

Some transmission systems have their working parts exposed to the elements, grit, mud, water etc.
This can lead to premature failure, high maintenance & a depreciation in performance.

Conclusion.

The transmission system must be fully enclosed to prevent any ingress of water & dirt.

A WHEELCHAIR TRANSMISSION SYSTEM HAS BEEN DESIGNED & MANUFACTURED THAT ADDRESSES & SOLVES ALL THESE ISSUES.

1. IT HAS PUSH & PULL DRIVE & CAN TURN WITH NO LOSS OF POWER.
2. IT CAN BE DRIVEN IN A STRAIGHT LINE EVEN WITH ONE ARM.ONE HAND.

3. IT HAS 5 GEARS TO SUIT INCLINES & FOR INCREASED SPEED.

New "drive blade" system has a continuously variable transmission with a range of 400% it will tackle even the steepest inclines with ease, automatically selecting the appropriate gear. 

4. THIS WHEELCHAIR CAN TURN UNDER FULL POWER FROM BOTH HANDLES. BRAKE ONE SIDE; PUSH & PULL BOTH HANDLES & ALL THE POWER GOES TO THE UNBRAKED WHEEL. USING ONE BRAKE DOES NOT SLOW THE WHEELCHAIR DOWN, IT SIMPLY DIVERTS THE POWER TO THE OTHER WHEEL.

5. IT WILL TURN ON ITS OWN AXIS USING ONLY ONE HAND RIM. BY ROTATING ONE WHEEL BACKWARDS USING THE HAND RIM THE DRIVE SYSTEM AUTOMATICALLY ROTATES THE OPPOSITE WHEEL FORWARDS. THIS IS A FAR TIGHTER TURNING CIRCLE THAN ROTATING AROUND ONE WHEEL. 

6. THE TRANSMISSION SYSTEM IS FULLY ENCLOSED. JUST HOSE DOWN TO REMOVE DIRT, ALL WORKING PARTS ARE SEALED.

7. SAFETY: THE DISK BRAKES CAN BE USED EVEN WHEN THE TRANSMISSION IS DISENGAGED. NO ROLLBACK ON INCLINES WHEN USING TRANSMISSION - REMOVE HANDS FROM LEVERS NO ROLLBACK OR LEVER MOVEMENT OCCURS.

8. BRAKE DISKS MOUNTED INSIDE FRAME & DOES NOT INCREASE WIDTH OF WHEELCHAIR. BRAKES MOUNTED ON TOP OF DISKS, AWAY FROM THE GROUND FOR PROTECTION WITH WHEELS REMOVED.

9. STANDARD WASHERS CAN BE USED TO VARY THE WHEEL CAMBER ANGLE.

10. ANY WHEEL CAN BE USED BY REPLACING ONE BEARING WITH A PUSH FIT ADAPTOR.

Please see the images below of the alpha prototype with all the above features included. The model performs exceptionally well & a lightweight version will soon be available.

This prototype is available for demonstrations.

Interested parties requiring an independent viewing to help with their design can contact me via the contact page.

Please see video presentation at top of page.

INBOARD DISK BRAKES NO ADDED WIDTH                                               SPLIT  FINAL DRIVE       

                                             

         5 GEARS !!                                                   500mm DRIVE LEVERS FOR INCREASED TORQUE    

      SINGLE DISENGAGING LEVER                              FULLY ENCLOSED TRANSMISSION

Since completing the manufacture of the original prototype Willgo wheelchair transmission, we have a huge range of spares for disposal.

Please call for latest stock.