Abstract:
An assembly ( 72 ) including a brake ( 70 ), or a brake with guide wheel ( 69 ) combination centrally integrated within a levitating fluid caster. Assembly ( 72 ) levitates heavy loads upon a near frictionless pressurized fluid, and also controls stopping or guiding movement of loads.

Description:
BACKGROUND 
     1. Field of Invention 
     This invention applies to the industry concerned with guidance and propulsion of heavy loads from place to place about a floor in an industry where loads levitate upon a pressurized fluid caster during transport. More particularly, this invention integrates within the caster plenum cavity a brake or a brake with guide wheel combination 
     A different industry disclosed inventions with a discrete brake assembly or a discrete brake with guide wheel combination assembly within a ground effect trunk. A represintative invention in this art includes that disclosed in U.S. patent Ser. No. 3,592,285 granted to Noble Jul. 13, 1971. This industry is different from the fluid caster industry of this invention. These ground effect vehicles such as amphibious boats or airplanes do not levitate upon fluid casters. They levitate instead by an air foil trunk formed an enormous flexible skirt surrounding the periphery of the vehicle. 
     2. Description of Prior Art 
     In the fluid caster industry of my invention, a load, not a vehicle, levitates near frictionless upon multiple fluid casters attached beneath the load. It often takes surprisingly low forces to move the levitated load. On flat floors, relatively smaller loads move by an operator pushing or pulling the load by band. Heavier loads often propel by a motorized transporter. A problem is not so much in getting load to move, but to stop its inertia safely and quickly once it gets moving, especially down a slight grade. Prior fluid caster art inventions have somewhat solved the stopping problem by attaching a brake assembly to the bottom of load separate from the fluid caster. Such invention is similar to that disclosed in U.S. patent Ser. No. 3,752,331 granted to Colburn Aug. 14, 1973. Also, it is most difficult to guide load in a direction of motion desired by the operator. Even the slightest uneven floor condition can cause the load to swing or drift laterally. Prior art inventions have somewhat solved the guiding problem by attaching a guide wheel assembly to the bottom of load separate from the fluid caster. Such invention is similar to that disclosed in U.S. Pat. No. 3,829,116 granted to Burdick Aug. 13, 1974. Another prior art invention has combined the fluid levitated caster with a guide wheel attached within the caster plenum. This invention integrating fluid caster with guide wheel was disclosed in U.S. Pat. No. 3,390,736 granted to Thomas Jun. 28, 1966. Another novel load guiding and stopping invention is disclosed in the copending U.S. Pat. application of Jason L. Smith, Ser. No. 09/528,652, filed Mar. 20, 2000, entitled ‘Guide Wheel Integrated with Ground Rubbing Brake Controls Fluid Levitated Loads’. It is assigned to the same assignee as the present application. This invention somewhat solves the stopping and guiding problems simultaneously by attaching an assembly to load bottom that integrates both the brake and guide wheel functions together in one assembly. 
     Both the brake separate assembly and sate brake with guide wheel combination assembly are expensive. Both assemblies take significant effort to attach to load often including drilling and tapping of holes and bolt and nut fastening. Both assemblies may be impossible to attach directly under load as often there is minimal available space that is unoccupied either by fluid caster devices or some other load structural feature. 
     My invention has the advantages over systems using conventional fluid casters with separate brake assembly, and/or with separate guide wheel assembly of: 
     i. lowering the cost of adding a brake function or adding a guide wheel with brake function to a fluid caster levitated system 
     ii. decreasing the weight of added brake function or added guide wheel with brake function to a fluid caster levitated system 
     iii. reducing set up time and attachment complexity of adding brake function or added guide wheel with brake function to a fluid caster levitated system 
     iv. decreasing attachment footprint area of adding brake function or added guide wheel with brake function to a fluid caster levitated system. 
     SUMMARY OF THE INVENTION 
     My invention integrates a fluid caster and a brake or a fluid caster and a brake with guide wheel combination into a single assembly. This invention results in a unique device that not only levitates a heavy load for transporting, but can also stop or guide load. Many unexpected advantages result from the combined invention of fluid caster and brake, or fluid caster and brake with guide wheel combination. 
     Prior art total transport systems typically use separate fluid casters, and separate brake. My invention is not larger in physical size than that of prior art fluid casters alone performing similar levitation. Therefore, the total transport system attachment area using my invention is much less than prior art transport systems. 
     The weight of my invention is far less than a comparable prior art caster, plus a separate brake assembly. 
     My invention has an advantage of requiring many fewer parts than a comparable prior art caster, plus a separate brake assembly. 
     My invention has an advantage of costing far less than a prior art comparable caster, plus a separate brake assembly. An unexpected advantage of my invention is that it can be attached to transported load far easier. It requires a much reduced size footprint area. It requires many fewer holes and bolt connections than prior art casters, with separate brake assemblies, or with separate brake with guide wheel combination assemblies. 
    
    
     By way of example, my invention is illustrated herein by the accompanying drawing, wherein: 
     DRAWING FIGURES 
     FIG. 1 is perspective view of a several fluid casters with integrated brake and wheel shown interconnected to a load base including symbolically represented fluid power controls. 
     FIG. 2 is a perspective exploded view of fluid caster with integrated brake and wheel alone showing more detail. 
     FIG. 3 shows a fragmentary sectional elevation view taken as suggested by lines  3 — 3  of FIG. 2 as load is levitated, guide wheel is and brake is raised. 
     FIG. 4 shows a fragmentary sectional elevation view taken as suggested by lines  3 — 3  of FIG. 2 as load is levitated, brake is raised, and guide wheel is forced to floor. 
     FIG. 5 shows a fragmentary sectional elevation view taken as suggested by lines  3 — 3  of FIG. 2 as load is levitated, and brake is forced to floor. 
     FIG. 6 shows a bottom plan view of the assembly of FIGS. 2-5. 
     FIG. 7 shows a bottom plan view of a square shaped alternative embodiment of the assembly of FIG.  6 . 
     FIG. 8 shows an air bag alternative embodiment fragmentary sectional elevation view of the assembly of FIG.  4 . 
     FIG. 9 shows an air bag alternative embodiment of the assembly of FIGS. 3,  4 , or  5  with brake only. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     1. The Invention Preferred Piston Actuator Embodiment in General 
     The view of FIG. 1 shows three assemblies of my invention ‘fluid levitated caster integrating brake or brake with guide wheel combination’ referred to as numeral  72 . Assemblies  72  attach to a heavy load  76  that moves upon a load base  66  structure. Load base  66  levitates just above a floor via pressurized fluid plenums created beneath assemblies  72 . Assemblies  72  have affixed a tube  20  that conveys pressurized fluid to the plenum cavity. A facility pressurized fluid source  40 , such as an air compressor or pressurized tank, plumbs to a levitation pressure regulator  54 . Regulator  54  output plumbs to a levitation valve  56 . The output from valve  56  conveys using flexible hose to levitation tube  20 . Assembly  72  would typically boll to the bottom of load base  66  via bolts extending though mounting holes  26 . Beneath one of the assemblies  72 , is shown an exploded view details of a brake  70  and a guide wheel  69 . Assembly  72  has affixed another tube  18  that conveys pressurized fluid during actuation of either the braking function or the wheel guiding function. The view of FIG. 6 shows a bottom planar view of assembly  72 . A center subassembly, referred to as numeral  46 , includes both the brake and the guide wheel functions integrated together. 
     2. Pressurized Modes of Operation 
     Assembly  72 , shown in FIG. 1 view, includes several modes of operation depending upon pressures applied to tubes  18  and/or  20 . One mode occurs when load base  66  levitates off the floor as p fluid flows into tube  20 . The fluid bearing levitation principles and details are well known to those skilled in the art In this levitation only mode, shown best in FIG. 3, while levitated, brake  70  and guide wheel  69  are both raised off a floor. Floor is identified in FIG. 3 as a line, and is referenced as numeral  68 . This mode occurs when no pressurized fluid enters tube  18 . In another mode, shown in FIG. 4, guide wheel  69  on forces to floor  68  by low pressurization conveyed to tube  18 . At a final mode, shown in FIG. 5 view, brake  70  forces to floor  68  by high pressurization conveyed to tube  18 . 
     The mode of operation shown in FIG. 3 view is useful when neither brake function nor guide wheel function is desired. This mode is selected when load base is being rotated or s to a new direction of motion. The other pressurized modes shown in views of FIGS. 4 and 5 are evoked by operator as they manipulate a wheel valve  58  or a brake valve  60  of FIG. 1 view. These modes of operation are useful when either load guidance or stopping are desirable. Details of the operation of valves  58  and  60  will be presented next. 
     3. Fluid Controls 
     Fluid controls shown in FIG. 1 are not part of my invention  72 . However a description of their functioning would help in understanding assembly  72  operation. Facility pressurized fluid supply  40  plumbs to a wheel regulator  52  and to a brake regulator  50 . Wheel regulator  52  adjusts to a pressure corresponding to downward force desired on wheel  69 . Brake regulator  50  adjusts to a pressure corresponding to downward force desired on brake  70 . Subassembly ‘brake integrated with guide wheel’  46  of FIG. 3 operation necessitates that wheel regulator  52  pressure be set less than the pressure of brake regulator  50 . The reason for its lower pressure setting will become apparent soon. Low pressure applied to tube  18  forces only wheel  69  to floor  68  whereas high pressure forces brake  70  to floor  68 . 
     The output fluid from wheel regulator  52  and brake regulator  50  plumbs to wheel valve  58  and brake valve  60  respectively. Fluid exiting valve  58  plumbs through a check valve  74 . Check valve  74  is oriented to prevent higher brake regulator  50  pressure from ever bleeding through the self relieving feature of wheel regulator  52 . The fluid exiting valves  74  and  60  plumb together and connects with flexible hose to tube  18 . When wheel valve  58  opens, a low pressurization reaches assembly  72  and subassembly  46 , and wheel  69  forces against floor  68 . When one or more guide wheels of a transporter system are in forced contact with a floor, they constrain a load to move in a direction perpendicular to wheel axle. If more than one guide wheel is used in a transporter system, they all orient in the same direction. Referring to the view of FIG. 1, when brake valve  60  opens, a high pressure present via brake regulator  50  conveys to assembly  72  and subassembly  46 . The high pressure forces brake  70  to floor  68  stopping load base  66 . 
     4. Invention Construction Detail 
     More details of my invention  72  operation and construction show in the view of FIG. 2. A ring shaped cylinder  15  attaches without leakage to a disk shaped flange  12  defining a cavity within cylinder  15 . An array of mounting holes  26  extends through flange  12  exterior to cylinder  15 . Holes  26  facilitate bolting assembly  72  to load base  66 . Flange  12  shown in the view of FIG. 2 includes within its thickness a radial fluid passage  22  extending from the periphery to the center point At this center point, a port  24   a  conveys one end of passage  22  to cylinder  15  cavity. The outer end of passage  22  has attached, without leakage, tube  18 . An annular shaped ring  16 , matching cylinder  15  diameters, includes a series of bolt holes  42   c  that match similar tapped holes  42   a  extending partially through cylinder  15  length. A flexible diaphragm  14  element sandwiches between cylinder  15  and ring  16  with bolts  34  forming a leakproof seal. Diaphragm  14  includes a matching series of bolt holes  42   b  accommodating clearance for bolts  34 . Diaphragm  14  is made from thin, medium hardness, polyurethane material which provides gasket sealing, abrasion resistance, and flexibility properties. The center point of diaphragm  14  includes a fluid port  24   b  through which pressurized fluid can pass as it enters subassembly  46 . 
     Internal to cylinder  15  cavity and partially through flange  12  is another array of tapped bolt holes  28 . A matching bolt hole array  32  perforates diaphragm  14 . Brake with integrated guide wheel subassembly  46  includes a matching bolt pattern  38 , and attaches via bolts  62  to tapped holes  28  within flange  12 . Diaphragm  14  sandwiches between flange  12  and subassembly  46  forming a leak proof seal. 
     A radial passage  76  perforates through cylinder  15  wall. Tube  20  attaches to the outside end of passage  76  without lee. Fluid pressure entering tube  20  will pressurize flange  12  side of diaphragm  14  forcing it outward. Flexible diaphragm  14  balloons under pressure tending to form a bulbous shape. 
     FIG. 3 views show a cross section of diaphragm  14  taken by section line  3 — 3  of FIG. 2 at its ballooned or pressurized state. The outside surface of diaphragm  14 , nearest ring  16 , contacts floor  68  over which load base  66  moves. The floor contact area shape with diaphragm  14  is much like a narrow annular ring. The views of FIGS. 3,  4 ,  5  all show assembly  72  as pressurized fluid conveys to tube  20 , through passage  76 , ballooning diaphragm  14 , downward to floor  68 . Pressure within diaphragm  14  inscribed by the floor contact ring, pushes against floor  68 . This pushing force levitates the entire assembly  72  including load base  66  and load off floor  68 . A few orifices  30  shown in the view of FIG. 2 perforate diaphragm  14 . Orifices  30  allow just enough pressurized fluid to escape to “lubricate” the floor contact ring of diaphragm  14 . The lubricating fluid under floor contact ring lifts diaphragm  14  surface off floor  68  a minute distance, in the magnitude of one or two one-thousands of an inch. The escaped fluid lubrication particulars are well known to those skilled in the art and are disclosed in related inventions. 
     Referring again to the view of FIG. 2, subassembly  46  includes an inner fluid port  24   c . Pressurized fluid entering tube  18  flows through passage  22 , through ports  24   a, b, c  and into subassembly  46 ; thereby forcing either guide wheel  69  or brake  70  against floor  68 . Low pressure actuates guide wheel  69  only and high pressure actuates brake  70 . The lowermost surface of brake  70  is offset a distance shown as distance D from the lowermost wheel  69  cylindrical surface in the views of FIGS. 3,  4 . In this manner, wheel  69  can guide load base  66  while brake  70  is not in floor contact. The view of FIG. 4 shows guide wheel  69  forced to floor  68  while brake  70  is offset from floor  68  by distance D. As tube  18  receives a greater pressurization, wheel  69  reaction forces with floor  68  pushes against a compressive spring. As wheel  69  reaction force builds, wheel  69  facts distance D to brake  70  surface. When wheel  69  retracts distance D, brake  70  will contact and push onto floor  68  and stop load base  66 . 
     The view of FIG. 5 shows brake  70  in forced contact with floor  68 , and with guide wheel  69  retracted within brake  70  surface. More details of subassembly  46  operation can be found in the copending U.S. application Ser. No. 09/528,652 described above of Jason L. Smith entitled ‘Guide Wheel Integrated with Ground Rubbing Brake Controls Fluid Levitated Loads’. 
     Referring to the view of FIG. 2, preferred materials for cylinder  15 , ring  16 , flange  12 , tubes  18  and  20 , and basic structure materials for subassembly  46 , are strong rigid materials such as metal, plastic, composite fiber. The preferred material is aluminum or steel because it is strong, easily joined and castable. Permanent joining of tubes  18  and  20 , flange  12 , cylinder  15  can be accomplished with welding, casting, brazing, silver soldering, and adhesives. These suggested materials and design configurations are those that work well with this invention. Other embodiments, however, using different materials and design configurations are included within the scope of this invention. 
     5. Alternate Embodiment 
     Basic Shape 
     Alternate embodiments of my invention can include other basic shapes such as a rectangular caster structural shape as that shown in the view of FIG.  7 . The subassembly  46  of this rectangular embodiment can be the same subassembly  46  of the view of FIG.  6 . 
     6. Alternate Embodiment 
     Brake Only 
     An alternative embodiment of my invention not shown can include a similar subassembly  46  to that shown in FIG. 2 except guide wheel  69  is omitted. This embodiment is useful if the operator wishes to only stop load base  66  being transported and is not concerned with guiding load base  66 . 
     7. Alternate Embodiment 
     Air Bag Actuator 
     Another alternative embodiment of my invention  72   b  shows in FIG.  9  and includes an integrated pressurized fluid bag actuated brake subassembly. With this subassembly, load base  66  stops by a brake  70  that attaches to a pivotal arm  84 . Arm  84  rotatably attaches to pivot  88 . Air bag  82  positions above arm  84  and is brake  70   a  forcing element of this design. As process fluid enters tube  18 , it conveys trough passage  22 , ports  24   a, b, c  and into air bag  82 . As air bag  82  inflates, it forcibly rotates arm  84  about pivot  88  pushing brake  70   a  against floor  68 . As fluid pressure within tube  18  returns toward atmospheric, brake  70   a  and arm  84  lifts off floor  68  by a return spring  92 . Another alternative embodiment of my invention shows in the view of FIG. 8, and is referred to as numeral  72   c . This embodiment includes an integrated fluid bag actuated subassembly disclosed in the U.S. Pat. Application mentioned above by Jason L. Smith. This invention is called ‘Guide Wheel Integrated with Ground Rubbing Brake Controls Fluid Levitated Loads’. In this assembly  72   c , load base  66  stops with a brake  70   b  or guides with a wheel  69   a . Both brake  70   b  and wheel  69   a  attach to a pivotal arm  84   a . Arm  84   a  rotateably attaches to pivot  88 . An air bag  82  positions above arm  84  and is the forcing element of this design. Pressurized fluid conveys to tube  18 , and plumbs through passage  22 , ports  24   a, b, c  and into air bag  82 . As air bag  82  inflates, with low pressure, it forcibly rotates arm  84  about pivot  88  and pushes wheel  69   a  only against floor  68 . As higher pressurized fluid enters tube  18 , air bag  82  inflates with greater force, and pushes harder on arm  84 . As rotating arm  84  forces harder toward floor  68 , wheel  69   a  axle retracts within a slot in arm  84   a . Retracting wheel  69   a  pushes against a compressive spring pad  9 . As wheel  69   a -retracts, brake  70   b  forces contact with floor  68  stopping load base  66 . As fluid pressure within tube  18  returns toward atmospheric, brake  70   b , and wheel  69   b  lifts off floor  68  by a return spring  92 . 
     For purposes of exemplification, particular embodiments of the invention have been shown and described to the best understanding thereof. However, other embodiments can include other brake or brake with guide wheel combination assembly integrations with a fluid caster, irrespective of particular structure, materials, and plumbing without departing from the spirit and scope of the claimed invention.