from the origin of the concept

to your business application

  1. Current actuator systems

a.Linear actuator

A linear actuator develops high forces as long as the cylinder axis is perpendicular to the lever. The weight of a linear actuator is of importance: the greater the range of motion to be provided, the longer and heavier the actuator must be. Moreover, the cylinder limits amplitude, as its axis must remain above the point of rotation, otherwise the effect is reversed and in addition, the risk of the rod buckling must be aken into account.






b Rotary engine

A rotary engine has a constant force no matter what the position of the arm or ground base, but its torque is dependent on power input, which thus imposes a proportionate engine weight.

  1. Summary

Both linear actuators and rotary engines are motors that are dedicated to a single base/lever combination. Assistance from successive rotary engines or linear actuators is not possible.

  1. Origin of the concept and initial developments

In his physiotherapy practice, Nicolas de Lussy experimentally observed that the way in which the workings of the muscles had been described in terms of biomechanics was not correct with respect to force. If we consider that a muscle resembles a simple actuator with the tendon located in the centre of the forearm (Dr. Hugh HUXLEY, Dr. Jean HANSON, 1954), force calculations result in values that exceed the maximum tensile strength limits that tendons, collagen and muscle fibres can withstand without damage. Nicolas de Lussy proceeded to make a correlation between muscle function (arm motion) and lozenge deformation following application of transverse thrust forces.

This manner of converting motion can be seen in the animal kingdom (conversion of muscle movement) and in industrial applications in the form of jacks, accordion-type elevators, etc.


The initial objective was therefore to adapt transverse thrust force to conversion of motion. Initial mock-ups were built to illustrate the principle. They were made of wood using off-the-shelf materials and components.

Right from the outset, the results proved the concept.

Nicolas de Lussy then decided to automate and simplify the system. By way of example, the first full version included 24 different actuators. The latest mock-up comprises 10 actuators and it is intended to reduce this number to six.

  1. Theoretical phases

a.Theoretical research was initially physiological and biomechanical, the aim being to extract the different mechanical elements in play and break down their respective actions.

b.During the applied research phase, the identified actions were reproduced to comprehend the mathematical relationships involved. The deduction was that transverse thrust was employed to activate a lever arm requiring peak forces ranging from zero to half of the minimum peak force required by current actuator systems (rotary engines or linear actuators).

Push4M, with its new pioneering approach, is disrupting the physical limits inherent in current actuators.

  1. Industrial targets

Following numerous optimisations, we have produced a compact motor with a selected power output.

Using home-made equipment and armed with both mathematical and physical understanding of the phenomenon, we have proven that it is possible to lift a 20 kg weight positioned at the end of the lever arm with a machine weighing 50 kg; this can already be considered to be high performance, compared to machines currently used in the construction industry sector.

The aim was then to adapt this concept using common components in order to improve reliability and capacity. This challenge has become a reality – the V10 prototype is underway in partnership with Mechanical Engineering department of the National Institute of Applied Sciences (INSA), Lyon.

Our study of the construction industry market has confirmed that the major players (VINCI, BOUYGUES, COLAS, KILOUTOU, EIFFAGE, etc…) are all awaiting a machine weighing less than 200kg that is able to routinely lift 50kg and also do handle up to 300kg. To capture this market, it was essential for use to produce a demonstration prototype.

First adaptation: Push4M anticipated what was possible compared to a Brokk60 demolition machine.

c) Collaboration with major construction groups

An alliance with a major construction industry player enabled us to define the requirement – a co-robot to assist construction site operatives. Push4M then designed a machine for construction industry purposes using the articulated V9 PROTOTYPE as illustrated below, a machine that can accommodate several end tools.

Consultations with a major construction equipment leaser over a period of 8 months enabled us to expand the machine to enable drilling of 300,000 and 700,000 holes of 60 to 300 mm in diameter at 3 metres from the ground in vibrated concrete walls. The result was a light, agile machine 1.50 m high working off standard worksite power sources.

This in-depth study required several machine evolutions to allow for angular displacement, CAD-CAM feasibility and technical integration in the required space .

Unfortunately, neither of these two companies was in a position to industrialise the machine as it did not form part of their core business strategy.

b. The future of PUSH4M – a co-robot to assist on-site operatives

Push4M’s patented design, by liberating factory robots from their stands, paves the way to the market for small machines meeting the needs of the major construction industry players.

Prototype V10 demonstrating the proposed features is currently in the process of finalisation at the Mechanical Engineering Department of INSA, Lyon.

It is scheduled to be presented in June 2018, providing proof of the industrial concept. Our aim is to forge further partnerships with construction machinery manufacturers.

A two-axis travelling prototype is now PUSH4M’s priority.

If you or your partners wish to support innovation that will improve productivity in the construction and agricultural sectors, improve working conditions and reduce the risk of musculoskeletal disorders, you are welcome to contact us!