WO1994020342A1

WO1994020342A1 - Unit for energy regeneration from vehicle braking

Info

Publication number: WO1994020342A1
Application number: PCT/IT1994/000019
Authority: WO
Inventors: Angelo Savelli
Original assignee: Angelo Savelli
Priority date: 1993-03-11
Filing date: 1994-03-03
Publication date: 1994-09-15
Also published as: DE688279T1; EP0688279A1; ITBO930085A0; IT1266290B1; AU6290494A; ITBO930085A1

Abstract

The Device presented enables energy lost by a braking vehicle to be stored and returned to the same vehicle to assist acceleration. Energy is stored in a spiral spring (M) that is made to rotate on its axis when a disk (dc2) unit connected to it is moved by an electromagnet (EMC) against another disk (dc1) connected to the engine. The stored energy is released when the disk (ds1) unit is moved in the opposite direction against another disk (ds2) mechanism that transmits the rotational motion to the wheels. The device is actuated by electrical circuits that are opened or closed by engaging and releasing the brake and clutch pedals.

Description

Unit for Energy Regeneration from Vehicle Braking

Technical Field

It is well known that considerable energy can be accumulated and stored in a spiral spring. The amount of energy is a function of spring height, thickness and the number of coils. It is equally 'well known that much of the energy produced to propel road and rail vehicles is absorbed by the brakes when the vehicle is slowed or brought to a halt. There is considerable economic interest therefore for a system which recovers the energy dispersed during braking, storing it in a suitably designed spiral spring and subsequently returning it to the vehicle on acceleration. Background Art

To my knowledge there are no devices currently available on the market that allow the energy generated, for instance, by an internal combustion engine and dispersed during braking to be stored and subsequently returned to the vehicle on acceleration. A survey of patents granted in Italy over the last twenty years failed to disclose any electromechanical or other devices designed for this specific purpose. Disclosure of the Invention

The device described below comprises readily available components such as wheelworks, friction drive disks to transmit rotary motion, electromagnets, various types of springs, shoe brakes, electrical conductors, switches, metal bars, plates and blocking lugs. The device is original both in the combination of these well-known parts and its application as an energy saving appliance. The appliance, hereinafter called < the Device > may be mounted, with the necessary adjustments, to all road and rail travelling vehicles. However, as the economic gains are directly proportional to the frequency of braking and acceleration, the category of vehicle for which the Device would be most indicated is easily identified. In the case of an urban passenger bus, driven^' by an internal combustion engine and operating on flat or only slight gradients, I have assumed that one third of the energy generated during acceleration could be recovered and stored during braking and then made available for the subsequent acceleration phase.

One third of the energy thus returned would be once again recovered during the following braking moment and so on.

The recovery or saving of the energy originally produced during the first acceleration phase would be:

Va + VaxVa+VaxVaxVa .... or almost one half of the energy generated. Account must be taken, however, of the additional energy requirement to propel a vehicle fitted with the Device. In the case of the above mentioned passenger bus carrying an average load, this would perhaps mean a 20% increase in overall mass.

If the acceleration energy requirement of the vehicle without the Device is 100, this will become 120 with the Device. Since the Device allows almost 50% energy saving, real energy consumption will be slightly more than 60, with a final saving of

40% on initial consumption.

If daily fuel consumption amounts to 100,000 Italian lire for a bus without the

Device, its use would allow savings of 40,000 lire a day, or more than 40 million in

3 years. As the efficiency of the Device depends largely, however, on driver competence and care, monetary incentives may be advisable. The following is a detailed description of the Device and how it works and is intended to be read with reference to the figures attached. They are not to scale nor are the various mechanisms indicated in the proportions suitable for greatest efficiency. The same parts are often depicted from different angles with the aim, not of providing accuracy to the millimetre, but rather of indicating the characteristics of the system proposed. In the event of practical application, all drawings will require refining accprding to the specific features of the vehicle.

The Device comprises spiral spring (M) (Figs. 17,18,22,23) placed in a fixed housing that can be provided with reinforcements (R) as shown in Figs. 1 and 2. The innermost end of Spring (M) is placed in an aperture in tube (T) which in turn is held against the outer housing by ball or roller bearings (Figs. 13 and 14) so as to allow rotational movement alone.

In its Resting Position (Figs. 1,2,3), tube (T) is prevented from rotating by bars (b) (Figs. 12,13,14) which slide into specially cut grooves in the tube, holding it fast. These bars protrude from the disk unit comprising disks (dc2), (ds2) amd inner tube (t). In the Resting Position, the disk unit is prevented from rotating since bars (bb), which protrude from it, become blocked by toothed stops (od) which in turn are fixed to the rigid spring housing (Figs. 6,7,8,9,11,12). Unless specific controls are actuated, the Device will remain locked in this Resting Position by <trap-like> blocking system (bt), shown in Figs. 6,7,8,9,10,11,12,13 and 14, even in the event of external shocks and jolts. In this position the vehicle is propelled by the power from the internal combustion engine alone. The Device may be actuated by closing an electrical circuit by means of the brake pedal. This energizes the unlocking electromagnets (em) which attract plates (pi), causing them to move and thus close contact with loading electromagnets (EMC), and release the < trap-like > blocking device retaining disk unit (dc2, ds2 and inner tube t) allowing the disk unit to move upward. Shoe brakes (fg) shown in Fig. 15 around tube (T) are also released, making rotation of tube T possible. The Device thus goes from the Resting Position (Figs. 1,2,3), in which spring (M) is neither loaded or unloaded and will preserve any energy it has, to the Loading Position, illustrated in Fig. 4.

Here disk unit (dc2, ds2 and t) has been pulled upward by bars (Be), themselves attracted by electromagnets (EMC), until it impinges upon disk (del) which rotates, being connected to the engine shaft. This rotational moment is transmitted by bars (b) which, as already described, engage with grooves in tube (T), sliding up and down depending on the position of the disk unit (Fig.13). Contact friction is reduced by roller bearings.

Tube (T) rotates in a pre-determined direction, transmitting its moment to spring (M) which becomes loaded to its maximum or until the dashboard control is actuated. Concomitantly the vehicle is slowed.

When spring (M) is fully loaded or the control actuated, electromagnets (EMC) and (em) are de-energized and the disk block, guided by springs (m) wound around the upper and lower extremity of tube (t), returns to the Resting Position. Bars (bb) on the disk unit travel downward and its four protruding lugs become blocked by toothed stops (od) which are part of < trap-like > blocking systems (bt). The (bt)'s have been released by springs (mm) and have moved back into the Resting Position as shown in Figs. 6 and 7. This is achieved fairly smoothly thanks to shoe brakes (fg) which grip tube (T) as soon as contact is opened. (Fig. 15 shows the shoe brakes in the disengaged position.)

Unloading Position. Here the spiral spring regenerates the stored energy, returning it to the vehicle on acceleration. The example given refers to a front- wheel-drive, front-engine passenger bus.

The depressed clutch pedal is released until it closes an electrical contact, allowing current tp go to the 4 (em)'s controlling the disk unit locking system. Disk unit (dc2, ds2 and tube t) now travels downward since electromagnets (EMS) and not (EMC) are energized. Fig. 5 shows the Unloading Position. The disk unit has been shifted downward by bars (Bs) until disk (ds2) rests against disk (dsl), transmitting rotational movement to it. A series of wheel gears will conduct this rotational moment to the rear wheels. In this way the energy stored in spiral spring (M) is reutilized for vehicle propulsion and acceleration. When spring (M) is completely unloaded or the dashboard control actuated, electrical contact is interrupted and, as will be described later in greater detail, the Device moves back to the Resting Position accompanied by springs (m).

Figs. 6 through 14 illustrate the < trap-like > blocking system (bt). In Fig. 14 metallic strips (bt) located on spiral spring (M) housing are shown when the Device is in the Loading Position. Electromagnet (em) has been energized thereby attracting plates (pi) and so retracting the metallic strips away from stops (od).In this way the unimpeded disk unit has moved upward until it rests against rotating disk (del) and so itself rotates as described above. As also described, motion will also be transmitted to tube (T) by bars (b) and hence to spring (M). The electrical circuit will be broken either when the spring is fully loaded or if the driver actuates a special command, at which electromagnets (em) and (EMC) will de- energize: disk unit (dc2, ds2 and t) will return to the Resting Position by means of springs (m) and, locking systems (bt) will move towards stops (od) and align with them. If, as illustrated in the view from above of Fig. 12, this inward movement is slightly out of phase with the < descent > of the protruding lug, the metal strips, which are mounted on hinge springs (mtn), will momentarily deflect on being struck by the lug (Fig.6). Once the lug has reached the centre of the toothed stop (od), the strip will spring back into its horizontal position on account of the greater force exerted by springs (mtn) compared to springs (mm) (Fig. 7).

This obviates friction contact between the curved edge of the metallic strip on blocking system (bt) and the lug.

The upper broken-line diagrams in Fig. 14 illustrate the position of bars (bb) in the Resting Position. The whole disk unit is prevented from rotating when the lug protruding from bar (bb) comes up against toothed stop (od). Also shown is the position of bars (b) in the grooves of tube (T).

The lower broken-line diagrams in Fig. 14 show the position of the locking system in the Unloading Position: blocking system (bt) has been withdrawn by plates (pi) thus allowing the lug to travel below the toothed projection of stop (od); disk unit (dc2, ds2 and t) makes contact with (dsl) and imparts the rotational moment in turn derived from the unloading spring (Fig. 5). As described above, the Device returns to the Resting Position once spring (M) is completely unloaded or a control actuated. Here too, should the (bt)'s slide back into the blocking position before the disk unit has < risen > , the lower metal strip will deflect upwards on being struck by the lug protruding from bar (bb) as shown in Fig. 8, thanks to hinge springs (mtn), returning, as described above, to the horizontal position once the lug is lodged in the centre of the toothed stop (Fig. 9). Fig. 10 presents the < trap-like > blocking system as seen from the (em) while Fig.11 gives the view from the opposite side (bar (bb) in the foreground). The descriptions given of the moving parts located above the housing of spring (M) also apply to the moving parts located below it (Fig. 2,3,4,5).

Although elementary, the electrical circuits controlling the working of the Device are somewhat complex to describe. Firstly there must be a push-button or lever switch on the dashboard of the vehicle (not illustrated) to enable the driver to energize the Device from the battery. Conversely, if the switch is not actuated the Device will remain in the Resting Position and the vehicle will run only on the power received from the engine. Secondly, for the Device to function, a forward gear must be engaged. As illustrated in Fig.32, an electrical wire connects the battery, the dashboard switch, the gear lever and conductor elements (ec) fixed to the lever. Engaging the gear lever closes contact between one of the (ec)'s and one of the other conductor elements (ecm), thereby allowing current flow to the brake and clutch pedals. The Device will not engage unless either the brake or clutch pedal is depressed and the vehicle will yet be propelled, but by the power from the explosion engine alone. Figs. 26,27 and 28 illustrate this Resting Position. Current flows from the battery through the dashboard switch and through the contact set up when any forward gear is engaged to two circuit segments: to conductor (pi), fixed to the mobile brake rod and to conductor (ql), fixed to the mobile clutch control rod. In this position, (pi) is in contact with fixed conductor (p2) which in turn connects to another fixed conductor element (ecil). Here the circuit stops since (ecil) is not mechanically connected to mobile conductor elements (eci2) and (eci3). Similarly current passes from (ql) to fixed conductor element (q2) and thence to fixed element (ecel) but here stops since (ecel) is not in contact with the moving conductor (ece2) and (ece3).

In this position, electrical current cannot reach electromagnets (em), (EMC) or (EMS).

By the same token, when both brake and clutch pedals are depressed fully the Device stays in the Resting Position B (Fig. 29) since the current reaching (pi) and (ql) does not close contact because in this position there is no mechanical connection with (p2) and (q2) respectively. Nor can current flow to electromagnets (em), (EMC) or (EMS).

Depressing the clutch pedal only and not the brake pedal will give Resting Position C, illustrated in Fig. 30. In this position (pi) and (p2) are in contact and current flows from them to (ecil) where it stops, (ecil) not being in contact with (eci2) and (eci3). Similarly, current arriving at (ql) can proceed no further, (ql) and (q2) not being in mechanical connection. Consequently, no electromagnet is energized.

Depressing the brake pedal only and not the clutch pedal will give Resting Position

D illustrated in Fig. 31. Current flowing to (pi) is arrested since (pi) and (p2) are not connected. Similarly, current flows from conductors (ql) and (q2), which are connected in this position, to (ecel) but is prevented from going further as (ecel) is not in contact with (ece2) or (ece3). Once again the electromagnets cannot be energized.

Loading Position. Depressing the brake pedal moves the brake control rod and hence conductors (ece2) and (ece3) so that they make contact with (ecel). The driver is aware when this connection has been set up by the slight resistance he feels on trying to exert greater pressure on the pedal.

Fig. 21 illustrates the situation: current from the battery flows through the dashboard switch and through one of the contacts on any of the forward gears to moving conductor (pi), but no further since this is disconnected from (p2). It also flows to moving conductor (ql) on the clutch contrόl^rod and so to fixed conductor (q2) and to (ecel), which in this position is in contact with (ece2) and (ece3). Current_;fthen passes from (ece2) to switch (int-c) located on spring (M) housing and indicated in Figs. 22 and 23 and in greater detail in Figs. 24 and 25. Here Spring (M) is fully, loaded causing insulating plate (spi) to project from an aperture in the housing and so deflect strip (1-c) and break the electrical circuit carrying current to the (em)'s.

Electrical contact is maintained as long as the spring is partially loaded and current will pass to all 4 (em)'s. Contact will also be closed to allow current to reach the (EMC)'s or loading electromagnets. In this case, however, current flows not from (ece2) but from (ece3) - the two conductors although part of one unit are joined by insulating bars. In fact (ece3) sends current only to the (EMC) or loading electromagnets and - as will be described below - current from (eci3) goes only to the (EMS) or unloading electromagnets. When (em) and (EMC) become energized, disk unit (dc2,ds2,t) moves upward, (dc2) makes contact with (del) which in turn transmits rotational motion coming from the engine through tube (T) to spring (M). (M) is loaded and the resistance set up to this rotational motion itself has a braking effect (cf. Fig. 4).

Braking continues as long as the driver actuates the pedal control, maintaining contact between (ecel), (ece2) and (ece3) either until the spring is fully loaded or until the vehicle has slowed to a stop.

If the brake pedal is fully depressed, mechanical contact between (ecel), (ece2) and (ece3) is lost. On releasing the brake pedal, curved insulating plate (eise) (Fig. 21 and the view from above in Fig. 27) is displaced with (ece2) and (ece3) on account of its rough surface, thereby ensuring the continued insulation of (ecel) during the pedal's upward travel.

Only once the pedal is fully released will -plate (eise) return to its original position and allow mechanical connection with (ecel) when the pedal is once more depressed.

Figs. 5 and 16 illustrate how the Unloading Position is achieved.

Here the clutch pedal, from being fully depressed, is slightly released until contact is made between moving conductor elements (eci2) and (eci3) on the pedal rod and fixed conductor (ecil). Again the driver is made aware that mechanical contact has been set up by the resistance encountered. At this point, the current coming from the battery flows through the dashboard switch and through the contact on any engaged forward gear to: (ql) where it is arrested, there being no contact with (q2), and (pi) on the brake rod, now in contact with (p2) and proceeds to (ecil) which, as described above, is mechanically connected to (eci2) and (eci3). From (eci2) current flows to switch (int-sc) located like (int-c) on the housing of spring (M) and indicated in Figs. 17,18 and in greater detail in Figs. 19 and 20. Here spring (M) is fully unloaded and insulating plate (spi) deflects strip (1-sc) breaking the circuit to the (em)'s. The circuit will remain intact if (M) is not fully unloaded, in which case the (em)'s will remain energized and current will also flow to unloading electromagnets (EMS). Here too the current does not derive from (eci2) but (eci3) - these two conductors being joined by insulating plates. In fact current passing through (eci3) will only go to the unloading electromagnets (EMS) while current from (ece3) passes exclusively to the loading electromagnets (EMC).

Once the (em)'s and (EMS) are energized, disk unit (dc2-t-ds2) moves downward until (ds2) makes contact with (dsl) and transmits the rotational motion from spring (M) through tube (T) to the (dsl) group and thence, by means of gear drive mechanisms, to the rear wheels.

This siti-vation will last either as long as the driver keeps the pedal in the same position, so maintaining contact between (ecil), (eci2) and (eci3) or until the spring is completely, unloaded, at which strip (1-sc) will be deflected by insulating plate (spi) and so break the circuit (Figs. 19 and 20). At this, disk unit (dc2-t-ds2) will return to the Resting Position and be blocked there by the small springs as described above. If the clutch pedal is further released contact between (ecil), (eci2) and (eci3) is interrupted and the Device returns to the Resting Position. Further release of the pedal will cause the explosion engine to reach its friction point with inevitable effects on vehicle motion.

If the released clutch pedal is once again depressed, conductors (eci2) and (eci3) will be displaced taking with them curved insulating plate (eisi) on account of the latter' s rough surface, thereby preventing contact with (ecil). Further depressing the pedal activates a spring and releases plate (eisi) which will return to its original position. At this point, if the pedal is released to a certain point, contact can once again be established between (eci2-eci3) and (ecil).

The various electromagnets can be equipped with controllers to avoid excessive wear. Electricity consumption to engage and disengage the Device is considerable. It may, therefore, be advisable that the standard battery charged from the engine's dynamo be modified to ensure an adequate potential difference.

As already noted, the above description and accompanying drawings are intended to provide only a general overview of the Device. At the prototype phase the various components will be designed in proportion to vehicle specifications. Similarly the gearing up and gearing down ratios between engine and spring (M) as well as between spring (M) and rear wheels will depend on the particular application..

The following is an approximate calculation of the travel distance necessary to fully load spring (M) - and subsequently unload it, assuming the housing to have a diameter of 140 cm.

The length of spring (M), whose thickness is 1/2 cm and with a distance between each coil in the < semi-loaded > state of 1/2 cm, will be equal to the average length of a coil x 70 coils (140/2). Average length is given by the circumference of a circle whose surface area is half the total S or s = ^ ^ = ^ 2^*0 = - J-SOO which is the S of a circle whose 0 is approximately 100. In fact 50 x 3.14 = 2500 x 3.14 -=-~7500. Average length is thus expressed as T100 =~300 cm. And 3 mt x 70 coils =~200 meters. When fully loaded the spring occupies half the total S, In other words, the spring completely occupies the above-mentioned circle whose diameter is approx. 100 cm. and radius approx. 50 cm with 100 coils.

When completely unloaded, spring (M) occupies the other half of the total S with a distance between the two circumferences of 70 - 50 = 20 cm. and hence with 40 coils. 100 - 40 = 60 turns are necessary to fully load the spring. In operating conditions of direct drive and with a wheel circumference of 2 metres, this signifies a travel distance of 120 m. With a ratio of 4 : 1, travel will be 30 m and with a ratio of 3 : 1, 40 m.

The same calculations apply, of course, to the unloading phase.

NB. A 10 cm high spring with a specific weight of 8 will weigh 0.4 kg/dm or 4 kg. per meter. Total weight will be around 800 kg.

As already mentioned, the description and drawings are indicative and do not give details of attendant components such as roller or ball bearings etc. which will be detailed in a subsequent application phase.

Brief Description of Drawings.

Sheet 1 - Fig. 1 Resting Position View from above

Sheet 2 t Fig. 2 Resting Position Front-rear view

Sheet 3 - Fig. 3 Resting Position

Side view

Sheet 4 - Fig. 4 Loading Position Side view

Sheet 5 - Fig. 5 Unloading Position Side view

Sheet 6 - Trap-like blocking systems

Fig. 6 Passage to the Resting Position (from the Loading Position)

Fig. 7 Attaining the Resting Position (from the Loading Position)

Fig. 8 Passage to the Resting Position (from the Unloading Position)

Fig. 9 Attaining the Resting Position (from the Unloading Position)

Fig. 10 (bt) blocking system - external view

Fig. 11 (bt) blocking system - inner view

Sheet 7 - Trap-like locking systems, toothed stops and shoe brakes

Fig. 12 Passage from Loading to Resting Position

Fig. 13 Loading Position - detail

Sheet 8 - Fig. 14 Loading Position and (virtually)

Resting and Unloading Position - detail

Fig. 15 Shoe brakes (view from above)

Sheet 9 Fig. 16 Unloading Position - side view (controls)

Sheet 10 - Complete Unloaded Position

Fig. 17 Side view Fig. 18 Horizontal section

Sheet 11 - Complete Unloaded Position - detail of switches Fig. 19 Side view Fig. 20 View from above

/. Sheet 12 Fig. 21 Loading Position , Controls - side view

Sheet 13 - Complete Load Position

Fig. 22 Side view

Fig. 23 Horizontal section

Sheet 14 - Complete Loaded Position - detail of switches Fig. 24 Side view Fig. 25 View from above

Sheet 15 Fig. 26 Resting Position A - Side view (controls)

Sheet 16 Fig. 27 Resting Position A - View from above (controls)

Sheet 17 Fig- 28 Resting Position A - Horizontal sections (controls)

Sheet 18 Fig. 29 Resting Position B - Side view (controls)

Sheet 19 Fig. 30 Resting Position C - Side view (controls)

Sheet 20 Fig. 31 Resting Position D - Side view (controls)

Sheet 21 Fig. 32 Gears (electrical contacts)

Sheet 22 Fig. 33 Main body of the Device Full side view

Best Mode for Carrying Out the Invention

One must first identify the type of road or rail vehicle best suited for the application of the Device. Since frequent braking and acceleration is essential for optimal exploitation of the invention, in my view^fhe ideal vehicle would be the urban passenger transport bus.

Subsequently, a detailed design would have to be drawn up and the size, mass and efficiency of the Device calibrated to the vehicle characteristics. Careful calculation will have to be made of the spacing and interaction times between me various parts to ensure smooth, efficient working.

Choice of materials is also important to ensure excellent cost-benefit ratios.

Industrial Applicability

Since the component parts of the Device - various types of springs, friction drive disk mechanisms, electromagnets, switches, wheel works etc. - are all readily available, the Device being original in the way these components are interconnected, industrial production should present no problems.

If the application of choice were to be for urban passenger buses, it should not be difficult to convince a competent manufacturer to produce several buses fitted with the Device. Costs would, of course, fall in proportion to the size of productipn.

Claims

1. A spiral spring fitted to a road or rail motor vehicle to accumulate and regenerate the kinetic energy dispersed during vehicle braking; said spring, being connected to a rotating part of the engine and hence theτ$ad wheels, becomes loaded by rotating on its own axis during vehicle braking. Energy regeneration is achieved by actuating a command causing the spiral spring to rotate in the opposite direction and so off¬ load the accumulated energy to the vehicle wheels during acceleration. The innovative feature of the spring is its application as an energy saving device as illustrated in Figs. 2,3,4,5,17,18,19,20,22,23,24,25 and 33, the latter being the <main drawing > .

2. The use of a single disk unit comprising two disks connected by an axial tube (or bar) and whose function is to enable loading and unloading of the spiral spring of Claim 1; in the spring-loading phase, said group is moved by electromagnets and curved bars until one of the two component disks impinges upon a third disk connected to the rotating part of the engine and so to the vehicle's road wheels; rotational motion thus passes from the disk unit by means of sliding bars to a larger

- diameter coaxial tube and so to the spiral spring whose innermost part is attached to said tube. Similarly, to regenerate energy and provide power for acceleration, the disk unit is shifted in the opposite direction by means of electromagnets and curved bars until the second of the two component disks impinges on a fourth disk connected to the vehicle road wheels: rotational motion passes from the spiral spring to the above-mentioned larger diameter coaxial tube, thence to the disk unit and so to the vehicle wheels, causing them to start turning or turn faster. Said disk unit is illustrated in Figs. 1.2.3.4.5.12.13.14.15.17.22 and 33, which is given as the <main drawing > . 3. The method of employing the < trap-like > locking system - indicated in the Figures as (bt) - in order to retain the disk unit of Claim 2 in the Resting Position and so preserve the energy accumulated in the spiral spring of Claim 1 until unloading (or inversely loading) is required. Said locking system comprises, among other elements: toothed stops (od) illustrated in Figs. 6,7,8,9,13,14 and 12, a view from above, and which impede bars (bb) attached to the disk unit of Claim 2 and so prevent the whole unit from rotating; upper and lower metallic strips that also hold the disk unit of Claim 2 in the Resting Position and which are retracted by means of electromagnets (em) to allow the upward or downward movement (to the loading or unloading position) of the disk unit. The same electromagnets (em) will cause contemporaneous opening of the shoe brake (cf. Fig. 15) and charging of other electromagnets (EMC or EMS) controlling spring loading or unloading respectively. Springs (mm) mounted on the support of the metal strips will cause these to return to their original position, and so hold the disk unit in the Resting Position, when the circuit to electromagnets (em) is broken. The relevant Figures are 1.

3.4.5.10.11.14 and Fig. 33, termed the <main drawing > .

4. The mode of employ of the electrical circuits and their relevant contacts, switches - a n d c o nt r o l s a s i l l u s tr a t e d s c h e m a t i c a l l y i n F i g s . 21,16,19,20,22,23,26,27,28,29,30,31,32. Said electrical circuits allow the Device comprising the spiral spring of Claim 1 and the disk unit of Claim 2 to pass to either the Loading or the Unloading Position or to be locked in the Resting Position, in which latter case the Device in no way intervenes with vehicle propulsion. Said electrical circuits comprise conductor elements, denoted on the drawings as (pi), (p2), (ecel), (ece2),(ece3),(ql),(q2), (ecil), (eci2),(eci3) which are located and connected in such a manner that the spiral spring of Claim 1 can only be loaded as shown in Fig.21, in other words, when the clutch pedal is fully released and the brake pedal partially depressed so as to allow conductors (ece2) and (ece3) to maintain contact with (ecel). Likewise, spring unloading can only take place as illustrated in Fig. 16, when the brake pedal is fully released and after the clutch pedal has been completely depressed and then released sufficiently to allow conductors (eci2) and (eci3) to maintain contact with conductor (ecil).

All other pedal positions break the electrical circuit, with the result that the Device comprising the spring of Claim 1 and the disk unit of Claim 2 is blocked in the Resting Position and any energy accumulated in the spring of Claim 1 is preserved. As shown in Figs. 27 and 28, conductor elements (ece2) and (ece3) and similarly, (eci2) and (eci3), are insulated from each other to avoid negative interference.