Abstract:
There is disclosed herein a device which can function either as a brake or as a clutch and which relies upon the application of fluid which, under sufficient pressure, becomes essentially solid thereby providing substantial friction between a moving disk and a stationery housing. The device includes a stationery housing having therein a rotating disk within a chamber in the housing. A fluid is applied to the chamber, and when the pressure on the fluid is sufficiently increased it becomes substantially a solid thereby essentially locking together the disk and the housing to provide a braking or clutching action.

Description:
BACKGROUND OF THE INVENTION 
     Various forms of brakes and brake systems are well known and have been used for years. For example, brakes have been used on automobiles from the beginning. In the early days of wheeled devices, the first brakes are believed to have been some sort of chock or anchor. In the early days of the bicycle a “spoon” brake involved a lever that pressed a block of wood against the wheel. In the early 1900&#39;s, the internal expanding drum brake was developed. Since then, numerous forms of brakes for automobiles and other devices have been developed. 
     Today, the typical brakes on automobiles are disc brakes, although drum brakes are still used. Disc brakes use a clamping action to produce friction between a rotor and pads mounted in a caliper attached to a suspension and actuation system. Inside the calipers, are pistons which press against the pads as a result of pressure generated in a master cylinder. The pads then rub against the rotor, thereby slowing the vehicle. Drum brakes usually use two semi-circular shoes to press outward against the inner surfaces of a steel drum. Older cars often had drum brakes on two or four wheels, and many new cars now have four wheeled disc brakes. 
     Other forms of brakes have been developed and used in various forms of equipment. Examples are electromagnetic brakes and clutches which usually include two rotors with magnetic particles disbursed in the air gap between both rotors, and an electric current passing through an associate coil creates a magnetic field which aligns the magnetic power into the gap. The higher the current, the more rigid the connection between the two rotors becomes. 
     As is known, the various forms of drum and disc brakes involve a number of moving parts and components. The electromagnetic particle brakes also suffer from several disadvantages, including a number of components, but also they may not be sufficiently effective at low RPM, and there can be problems in keeping the powder homogeneously between the gap between the rotors, and heat dissipation can be a problem. 
     SUMMARY OF THE INVENTION 
     The present invention is characterized by relative simplicity compared to prior brakes and brake systems. In its simplest form, it comprises a stationery housing containing a rotating disk therein with a shaft affixed to the disk and extending from the housing. The disk has a plurality of holes therethrough. Suitable bearings and seals are provided between the housing and disk, and the braking action is provided as a result of applying a pressurized fluid through a fluid port in the housing and into the cavity therein around and through the holes in the rotating disk. The fluid preferably is a polybutene grease which becomes solid through the application of pressure, but which is suitably liquid when the pressure is released. The device can be used either as a brake or a clutch, has no replicable parts, and no required maintenance. 
     Accordingly, it is the principal feature of the present invention to provide a new form of brake or clutch. 
     Another feature of the resent invention is to provide a new form of brake or clutch relying on a pressurizable fluid applied within a housing to controllably restrict the rotation of a rotating disc within the stationery housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and features of the present invention will become better understood through a consideration of the following description taken in conjunction with the drawings in which: 
     FIG. 1 is a cross-sectional view of an exemplary device according to the present invention principally designed as a brake, 
     FIG. 2 is a side elevational view of the device, FIG. 1 being taken along lines  1 — 1  of FIG. 2, 
     FIG. 3 is a detailed sectional view of the area identified as FIG. 3 in FIG. 1, 
     FIG. 4 shows details of an alternative embodiment, 
     FIG. 5 is a further detailed view of the structure in FIG. 3, to better illustrate, a coating at bearing surfaces, and 
     FIG. 6 is a further detailed view of the embodiment in FIG. 4 for a better showing of a coating at bearing surfaces 
    
    
     DETAILED DESCRIPTION 
     Turning now to the drawing, an exemplary brake is illustrated in FIGS. 1 through 3 and  5 . The brake includes a housing  10  comprising first and second, or rear and front, housing rings or sections  12  and  14 , and a rotary disc  16  disposed within an inner cavity  18  in the housing  10 . The disk  16  includes a flange  20  extending outwardly through the front housing  14  and to which a shaft can be attached, such as a shaft onto which an automobile wheel (not shown) would be attached. The rotary disk  16  includes a flat disk section  22  having a plurality of holes  24  therethrough. A fluid inlet port  28  is attached to the rear housing  12  for directing fluid  30  into the housing, and into the cavity  18  and through the holes  24  in the disk  16 . As will be explained further, when this fluid is supplied under suitable pressure, it becomes solid to essentially “lock” the disk  16  within the housing  10 , thereby providing a braking action. 
     Turning to additional details of the structure, the front and rear housings are held together by a plurality of suitable bolts  36 , and the two housing halves are sealed by a sealing O-ring  37  to keep fluid  30  from leaking out between the halves  12  and  14  of the housing  10 . The fluid inlet port  28  preferably is affixed to the rear housing  12  by threading the port into the rear housing  12  in a conventional manner. 
     Of particular importance, are the bearing and sealing arrangements between the disk  16  and the housing  10 , and this is shown in greater detail in FIG. 3 which is an enlarged sectional view of the circled section identified as FIG. 3 in FIG.  1 . As can be seen from FIG. 3, self lubricated plastic bearings  40 ,  41  are provided around the center portion of the disk  16 . The bearing surfaces adjacent the bearings  40 ,  41  can have applied thereto a baked dry film coating  54  to reduce friction. In particular, note the further detailed drawing of FIG. 5 which omits the bearings  40 ,  41  so that the location of the coating  54  is clear. Thus, the entire bearing surfaces adjacent to bearings  40  and  41  are coated at  54 , as are the surfaces adjacent bearings  52  and  53  which are described below. Preferably the coating  54  is a baked dry film coating which is only approximately 25 millionth inch thick. The coating  54  can be, for example, Everlube 620C available from Engineered Coating Solutions. 
     The tapered shape bearings  40 ,  41  are squeezed in place between the dry film surfaces  54  and, thus, each of the bearings  40  and  41  and the film coatings  54  fill up the gap between the disks  16  and respective housing sections  12  and  14 . The bearings,  40 ,  41  typically are 0.005-0.100 inch thick. The angle of the bearings  40 ,  41  as seen in FIG. 3 with respect to the center of the disk  16  preferably is 30°. 
     The fluid cavity  18  is sealed in a manner to prevent the fluid  30  from leaking out past the bearings  40 ,  41 . For this purpose, the disk  16  includes annular grooves  44 ,  45  and the housing sections  14  and  12  include similar annular grooves  48 ,  49 . Circular or ring shaped bearings  52  and  53  are disposed in the annular grooves  44 ,  45  and  48 ,  49 . The bearings  40 ,  41  preferably are Teflon (TFE) or TFE or Poly Urethane, 80D shore durometer based bearings and preferably a TFE based lubricant is also used. 
     As noted earlier, the fluid  30  preferably is a polybutene grease or lubricant which becomes more viscous and can become solid upon the application of sufficient pressure, and which is liquid when the pressure is released. Since this fluid solidifies under pressure and fills the cavity  18  and extends through the holes  24  in the disks  16 , the braking action previously noted is created, thereby stopping rotation of the disk  16  with respect to the housing  10 . An example fluid  30  is a polybutene lubricant sold by Amoco Chemicals Corporation, but other fluids which become sufficiently solid under pressure can be used. 
     The brake device of the present invention can be used for any application requiring a brake, such as for the wheels on cars, airplanes, trailers, and the like and whether the wheels are driven wheels or not. Although the flange  20  is shown as only extending through the front housing  14 , a like flange can be included on the other side of the disk and through the back housing  12  to provide a through shaft which extends through the housing  10  of the present device. Also, the device of the present invention can function as a clutch between the rotary disk  16  and, in this case, a rotatable housing  10 . 
     FIGS. 4 and 6 illustrate an alternative arrangement of a sealed bearing design for a brake system. In this embodiment, the housing sections  12  and  14  of FIG. 1 are in respective sections  12   a ,  12   b  and  14   a ,  14   b  for ease of assembly. The same is true of the disk which is in sections  16   a  and  16   b . Thus, housing sections  12   b  and  14   b  comprise a center section, and the sections  12   a  and  14   a  comprise an outer section, and these pairs of sections are held together by a series of bolts  13  and a series of bolts  15 . Similarly, the disk sections  16   a  and  16   b  are held together by a series of bolts  17 . As will be appreciated, the bolts  13 ,  15  and  17  preferably are evenly spaced around their respective housing members and disk. 
     Other than the sectioned components, the major difference in this embodiment is the bearing system comprising bearings  40   a  and  41   a . These bearings have a facing “V” groove configuration  40   b  and  41   b  as shown in FIG. 4 wherein the included total angle  41   c  preferably is 59 degrees and the lower included angle  41   d  preferably is 29 degrees. The bearings  40   a  and  41   a  are self-lubricated plastic bearing liners, preferably formed from polyurethane. 
     In this embodiment, the baked dry film coating  54  is applied only to outer surfaces of the central section  16   b  of the disk,  16  as seen FIG. 6. A like coating is not required on the housing sections  12   b  and  14   b  inasmuch as the bearings  40   a  and  41   a  are fixed in housings sections  14   a  and  12   a  respectively. No coating  54  is applied to bearings  40   a  and  41   a  because such a coating thereon is not necessary. As with the embodiment of FIGS. 1,  2 ,  3  and  5 , in this embodiment the bearing surfaces and “V” bearings surfaces  40   b  and  41   b  of bearings  40   a  and  41   a  do not touch any metal surfaces, just the coating  54 . 
     While embodiments of the present invention have been shown and described, various modifications may be made without departing from the scope of the present invention, and all such modifications and equivalents are intended to be covered.