Abstract:
An auxiliary brake system for a motor vehicle including a plurality of suction cups mounted on the chassis of the vehicle which are lowered into contact with a roadway during skids on icy or wet pavement.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an auxiliary vehicle brake, and more particularly, a suction brake for use in an emergency. 
     It is well known that in certain instances, for example, when sliding on icy or slippery roads, a normal vehicle brake is not only ineffective but is even dangerous to apply. Accordingly, this invention provides an auxiliary brake for use in such emergencies. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, one or more hydraulically reciprocable suction cups are mounted on the chassis of a motor vehicle. When a foot switch on the floor of the vehicle is depressed, a relay valve couples a vacuum unit to the engine drive to evacuate the interior of the suction cups through a two-way valve connected to each cup. Simultaneously, a reversible motor is actuated to drive a pump in a hydraulic circuit to cause a hydraulic cylinder to lower the suction cups vertically to the pavement to brake the vehicle. When the foot switch is released the coupling of the engine to the vacuum unit is disengaged enabling a second switch mounted on the dashboard to be closed which energizes a motor to drive a pump to pump air from a pressurized tank to the interior of each suction cup through the two-way valve relieving the suction in the cup. The motor coupled to the hydraulic pump is again actuated simultaneously to reverse the fluid flow in the hydraulic system to raise each of the suction cups to a stored position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Further objects and advantages of the invention will become apparent from the following description and claims and from the accompanying drawing, wherein: 
     FIG. 1 is a schematic bottom plan view of the chassis of a motor vehicle equipped with suction brakes in accordance with the present invention; 
     FIG. 2 is a schematic flow diagram of the vacuum and hydraulic circuits used to activate and release the suction brakes on the motor vehicle of FIG. 1; and 
     FIG. 3 is a side view in elevation, partly in section of one of the suction brakes mounted on the vehicle chassis of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawing in detail, wherein like numerals indicate like elements throughout the several views, one or more hydraulically reciprocable suction cup brakes 10 are mounted on the chassis 12 of a motor vehicle 14. 
     As shown in the flow diagram of FIG. 2, when a foot switch 16 on the floor 18 of vehicle 14 is depressed, a relay or solenoid valve 20 connected in series with vehicle battery 22 couples a vacuum unit 24 to the engine output drive 26 of vehicle 14 to evacuate the interior of each suction cup brake 10 through a two-way quick release vacuum valve 28 connected to the suction cup 30 of each brake 10 through a line 32. Valve 28 is of the quick release type, i.e. it can instantaneously be opened or closed as desired. Vacuum unit 24 can typically be a pump or blower which draws air from the interior of each cup 30. 
     Simultaneously, a reversible electric motor (not shown) is electrically actuated to drive a reversible pump 34, e.g. of the centrifugal type, to deliver hydraulic fluid from a reservior 36 through a two-way valve 38 to the inlet line 40 of a hydraulic cylinder 42 whose piston 43 is connected to suction cup 30 by a pivotal joint 45. Fluid is forced from cylinder 42 through an outlet line 44 and valve 38 and returned to reservoir 36. Evacuated suction cups 30 will contact the pavement to abruptly retard movement of vehicle 14 even on icy or slick roads. 
     When foot switch 16 is released, the coupling of vacuum unit 24 to the engine 26 is disengaged enabling a switch 46 mounted on the dashboard of vehicle 14 to be closed which energizes a motor 48 to drive a pump 50 to pump air from a pressurized tank 52 to the interior of each suction cup 30 through valve 28 in line 32, relieving the suction in each cup 30. The motor coupled to hydraulic pump 34 is again actuated simultaneously to reverse the fluid flow in the hydraulic system so that fluid enters each cylinder 42 through line 44 and egresses through line 42 to raise each suction cup 30 to a stored position. 
     As shown in FIG. 3 the bottom of each cup is threaded at 54 to the main body so it can be replaced due to wear.