Abstract:
A quick closing of a friction clutch for motor vehicles is provided by an arrangement where means acting in the same direction required for maintaining the clutch in the disengaged position are used to further close the clutch.

Description:
This is a continuation of application Ser. No. 458,121, filed Apr. 5, 1974, and now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to an arrangement for operating a friction clutch for motor vehicles, whereby hydraulic or mechanical means by action on a control lever a pressure disk is removed from engagement with a clutch plate. 
     Arrangements for disconnecting clutches for different motor vehicles are known, in which the clutch is disconnected by pressure of a lever operated by hand or foot and closed by return movement of this lever. The control lever is connected with the clutch by different hydraulic or mechanical devices. 
     Control arrangements are also known, where auxiliary power is supplied from the engine in order to reduce the force required for disengagement of the clutch. 
     A drawback of all mentioned systems, particularly when applied for special sport motor cycles is the impossibility of an instantaneous closing of the clutch, resulting in slower starting from rest. In a race, for instance, the driver holding the control lever waits for the signal for starting and releases the lever at this moment; he, of course, has to change the direction of action of the force being applied by his hand or foot by the lever. His reaction is therefore slower. 
     Automatic systems which would eliminate this drawback offer no favorable results for a quick start. 
     Summary of the Invention 
     It is an object of this invention to provide an arrangement for the control of the clutch of a motor vehicle which would enable virtually instantaneous starting, whereby the driver, to close the clutch, would apply a force on the control means of the clutch in the same direction as he uses for maintaining the clutch disengaged. For this purpose, the control means of the clutch are provided with additional means which are operated either independently from the control lever or which are operated by applying additional pressure on the already pressed down control lever. 
     The improvement achieved thereby consists in that the driver has the possibility of adjusting the control lever when starting to a suitable position and to close at the starting moment instantaneously the clutch either by pressing a control button or by a further movement of the control lever. This arrangement is particularly advantageous for special motor cycles adapted for races on dirt tracks, where a quick start is rather decisive for the result. 
    
    
     Description of Drawings 
     Examplary embodiments of arrangements according to this invention are shown in the attached drawings, where FIG. 1 is a schematic cross sectional view of an arrangement with a disconnected clutch; FIG. 2 shows the arrangement of FIG. 1 with a clutch closed by means of an auxiliary control button; FIG. 3 the arrangement of FIG. 1 with a closed clutch and returned control lever; FIG. 4 an alternative arrangement adapted for closing the clutch by further pressing the control lever; and FIG. 5 a still further alternative of an arrangement with a return valve. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to FIG. 1, a control lever 2 is arranged pivotably on the frame 1 and connected via a connecting rod 3 and a piston rod 4 with a main piston 5. The main piston 5 slides in the main cylinder 6, connected by the conduit 7 with the clutch cylinder 8. A clutch piston 9 contacting by its lifter 10 a pressure disk 11 is slidingly arranged in the clutch cylinder 8. The pressure disk 11 normally urges the clutch plate 12 against a base plate 13 to close the clutch springs (not shown). A valve 14, mechanically connected with an auxiliary control button 15, terminates into this main cylinder 6. The valve 14 permits the entrance of pressure liquid 16 into the auxiliary cylinder 17, where an auxiliary piston 18 is slidingly arranged. The auxiliary control button 15 is returned to its original position by a spring 19, the control lever 2 by a return spring 20. 
     The arrangement is shown in FIG. 1 in the disengaged position. In this case the driver acts with hand pressure on the control lever 2 and must overcome the resistance of clutch springs (not shown) and of the return spring 20. In this position the main piston 5 forces the pressure liquid 16 from the main cylinder 6 via the conduit 7 into the clutch cylinder 8. The clutch piston 9 presses via the lifter 10 against the pressure disk 11 and disengages the clutch. The valve 14 is closed due to the force of the spring 19 and due to the presence of the pressure liquid 16 which urges the valve 14 into its closed position. The driver controls the movement of the pressure disk 11 by action on the control lever 2. 
     In FIG. 2 the arrangement is shown with a clutch closed by means of the control button 15. If the driver wants to close the clutch instantaneously, he presses the auxiliary control button 15, opening thus the valve 14 and enabling admission of pressure liquid 16 to the auxiliary cylinder 17. The pressure liquid 16 shifts the piston 18 and fills the whole space of the auxiliary cylinder 17. Due to escape of pressure liquid 16 from the main cylinder 6 the clutch is closed, without need of changing the position of the control lever 2. 
     After a quick start of the vehicle, the driver releases the control lever 2, which has no further influence on the performance of the clutch. The whole arrangement comes thereby into the position indicated in FIG. 3. The return spring 20 returns after release of the control lever 2 into its original position. The main piston 5 sucks thereby pressure liquid 16 from the auxiliary cylinder 17, as the valve 14 is opened due to the pressure drop in front of the piston 5 in main cylinder 6, thereby overcoming the force of the spring 19. Thus the control arrangement is prepared for a further disengagement of the clutch and for its repeated closing either by the control lever 2 or by the auxiliary control button 15. 
     According to FIG. 4, the valve 14 is elongated so that its extension 21 reaches the control lever 2 in the pressed down position of the control lever which corresponds to a disconnected clutch. In the case of a further pressing down of the control lever 2, the extension 21 is simultaneously pressed down and the valve 14 opened, closing the clutch virtually instantaneously. After release of the control lever 2, the return spring 20 returns the control lever 2 to its original position, whereby the pressure liquid 16 is displaced from the auxiliary cylinder 17 into the main cylinder 6. 
     In all of the embodiments described above, the clutch can be quickly disconnected by applying pressure to close the clutch in the same direction as pressure is being applied to keep the clutch open. In contrast to the prior art, the direction of force application by the driver need not be reversed, thereby permitting the clutch to engage in a much shorter time than would otherwise be the case. 
     FIG. 5 shows an alternative of the disconnecting arrangement with a return valve, where a control lever 2, pivotably supported on the frame 1 is connected via a connecting rod 3 and a piston rod 4 with the main piston 5. The main piston 5 slides in the main cylinder 6, connected by the conduit 7 with the clutch cylinder 8. A clutch piston 9 contacting by means of a lifter 10 the pressure disk 11 is slidably mounted in the clutch cylinder 8. The pressure disk 11 presses the clutch plate 12 against the base plate 13 for a closed clutch by springs (not shown). 
     The arrangement comprises a return valve 22 fixedly connected to a control button 15, which in turn is provided with a return spring 19. When disconnecting the clutch by pressing down the control lever 2, the pressure liquid 16 opens the return valve 22 and the clutch is disconnected. As soon as the movement of the control lever 2 ceases, the return valve 22 closes due to the pressure of the spring 19 and the clutch remains in the adjusted disconnected position without need of pressing down the control lever 2. The clutch is closed by pressing the button 15, whereby springs (not shown) of the clutch exert pressure on the clutch piston 9. As a result, the pressure liquid 16 flows past the opened return valve 22 into the main cylinder 6. When conventional and normal operation of the arrangement for disconnecting the clutch is desired, the button 15 has to be maintained pressed down or secured in the pressed down position by an arresting pawl (not shown) so that the clutch may engage upon release of control lever 2. Quick closing of the clutch is obtained since the direction of force application on lever 2 to keep the clutch disengaged need not be reversed in order to close the clutch. 
     Modifications of the above-described embodiments may be made by those skilled in the art. It is intended to cover all such modifications which do not constitute departures from the spirit and scope of the invention as defined in the claims appended hereto.