Abstract:
A mechanically applied spring release brake ( 50 ) having a single small diameter dynamic seal ( 46 ) is integrated into a wheel and tire to provide for a small package utilized in forklifts, wheel trucks and other industrial vehicles.

Description:
This application is a national filing of PCT Patent Application Ser. No. PCT/US2003/035081 filed on Nov. 4, 2003, which claimed the benefit of Provisional Patent Application No. 60/423,568 filed Nov. 4, 2002. 
   FIELD TO WHICH THE INVENTION RELATES 
   This invention relates to an integrated brake and wheel package. 
   BACKGROUND OF THE INVENTION 
   Brakes have been used for stopping the movement of rotary objects such as scissorlifts or tow motor wheels, chain lift pulleys and others. These brakes come with drums, disks, increasing ramps, and other type of energizing devices. Typically, these energizing devices are large (necessitating a sizable diameter package), or require a separate mounting adjacent to the effected rotary device (necessitating a longer package). An example of such energizing devices are the Ausco series of brakes as typified in both the radial and axial versions (the former being inside a separate wheel and the latter being displaced laterally off of the end of a separate wheel axle). Other applications use large diameter external brake disks or internal brake drums (as for example used in present day separate wheel rim automobiles). Attempts to integrate the brake and wheel frequently have resulted in large sized devices (R. W. Brown U.S. Pat. No. 2,381,393, for example) or have produced complex mechanisms (Lemaire U.S. Pat. No. 5,333,705, Hydraulic Motor and Brake, for example). 
   The cost, complexity and/or size of these units have not produced a suitable integration of wheel and brake. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to integrate a disk brake inside a supported rotary member. 
   It is an object of this invention to reduce the cost of providing a braked wheel. 
   It is another object of this invention to reduce the stress on a wheel system when a hydraulically released brake is actuated. 
   It is a further object of this invention to provide for a compact mechanical brake application. 
   It is another object of this invention to provide for a more adaptable wheel brake. 
   It is a further object of this invention to reduce the physical and hydraulic complexity of the device associated with a brake. 
   It is another object of this invention to provide for a high torque mechanical brake in a small diameter unit. 
   It is yet another object of this invention to reduce the number of dynamic seals on rotary members in a brake. 
   It is still a further object of this invention to increase the speed of, and to simplify, the manufacturing integration of a braking rotary component into an associated vehicle. 
   Other objects and a more complete understanding of the invention may be had by referring to the drawing in which: 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a lateral cross-sectional view of an integrated wheel/brake/spindle combination. This FIG was taken substantially along lines  1 - 1  in  FIG. 3 ; 
       FIG. 2  is a further lateral cross-sectional view of the integrated wheel/brake/spindle of the present invention. This FIG was taken substantially along lines  2 - 2  in  FIG. 3 ; 
       FIG. 3  is a view of the left hand side of the unit of  FIG. 1 ; 
       FIG. 4  is a view of the right hand side of the unit of  FIG. 1 ; 
       FIG. 5  is a perspective view of the completed unit of  FIG. 1 ; and, 
       FIG. 6  is a hydraulically applied multiple coil spring released brake incorporating the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The invention of this application relates to a spindle mounted rotary member including an engagement mechanism. 
   The example brake assembly shown includes a braking mechanism  50  located between a spindle  20  and a tire  100 . 
   The spindle  20  serves to rotatively mount the tire  100  and contained braking mechanism  50  to an associated part. An example of this associated part would be the vehicle frame of a scissorlift. The particular embodiment would be bolted onto such frame (shown in dotted lines  200  in  FIG. 1 ) from the backside by bolts  201 . This would tightly retain the mounting plate  21  of the spindle to the frame  200  against the weight and dynamic loading to and from the vehicle or device (such as a scissorlift) and the tire  100 . Note that the particular mechanism  10  disclosed is spring applied and pressure released braking mechanism. Therefore, a hole  202  would be provided in the frame in order to allow a suitable selective pressurization hydraulic line  205  to be interconnected to the brake assembly  10 . (This hole  202  also aids in localizing and weight transfer between the spindle and the frame  200  due to flange  23  engaging the sides of the hole  202 .) 
   In addition to the mounting plate  21 , the spindle  20  has an enlarged primary bearing area  30 , a relatively reduced secondary bearing area  40  and a reduced oil passage extension  45 . 
   The enlarged main bearing section  30  serves to carry the primary weight of the vehicle by forming the primary interconnection for the main bearing  31  and the primary torque by the attachment of the reaction disks  33  thereto. It is preferred that the main weight loading of the wheel be through this ball bearing (being of large size and of proximity to the enlarged diameter plate  21  and frame, it can dissipate heat more efficiently). In addition, the preferred main bearing  31  as shown is a ball bearing located between the spindle mounting plate  21  and two separate snap rings  35 . One snap ring is internal to the spindle  20  and the other is external to plate  63 . Plate  63  has a small inner lip  65  adjacent to the outer inside edge of bearing  31 . This allows the bearing at this location to take the forces inwardly and outwardly between the wheel  100  to the frame  200  (i.e., separate thrust bearings are not necessary). 
   The secondary bearing area  40  aids in the support of the weight loading of the wheel. Incorporating a needle bearing  41  at this location also allows room and physical placement for the parts of the braking mechanism  50  radially outward therefrom. This lowers the necessary diameter of the housing  60  in respect to alternative bearings. It also allows the bearing outward of most of the braking mechanism  50 , thus aiding in reducing wobble and in localizing the later described dynamic seal  46 . 
   Located off the end of the secondary bearing area  40  is a reduced oil passage extension  45 . This reduced oil passage section is surrounded by the main dynamic seal  46  for the actuation mechanism. By being reduced in diameter, this has the effect of reducing the axial thrust of the “piston area” between the braking mechanism  50  and the spindle  20  during pressurization from line  205  (compare the area of the reduced oil passage extension  45  which would be necessary if a dynamic high pressure seal was located about the larger diameter  30  of the spindle with that of the main bearing  30 , for example). This reduces any axial shifting of the wheel  100  in respect to the spindle  20  upon the pressurization of the brake assembly  50 . This lengthens the service life of the package. 
   This dynamic seal  46  is also the only high pressure seal in the entire device which will routinely be subject to rotary movement between adjoining parts (all of the other parts of the brake assembly  10  are either located between two relatively immovable parts—the unitary housing  60  for example—or are located between a part which will be subject to rotative forces only during engagement and disengagement—the piston  57  for example. This design minimizes the necessity of complex manufacturing processes on adjoining parts (for example grinding) while also lowering the cost of parts (larger diameters of seals are of significant cost). 
   The brake mechanism  50  sits surrounding the spindle so as to mechanically rotatively interconnect the tire  100  to the spindle  20  as well as providing for a compact engagement mechanism. 
   The particular braking mechanism  50  includes a reaction support member  51 , a housing  60 , and a spinner nut locking member  80 . 
   The reaction support member  51  serves to interconnect the housing  60  with the outer needle bearing  41  thus to pass any radial forces therebetween. In addition the reaction support member  51  has an oil passage  52  which extends from the reduced oil passage extension  45  to the main activation cavity  54  adjacent piston  57 . As the activation cavity  54  is located between first and second piston seals  55 ,  56  the pressurization of the passage  26  in the spindle will cause movement of the piston  57  against the force of the disk spring  59  so as to deactivate the braking engagement mechanism. Upon the cessation of pressurization of the passage in the spindle, the piston  57  will move the other way due to the force of the disk spring  59 , this in turn will engage the braking plates  58  which are connected to the housing  60  with reaction plates  33  which are interconnected to the spindle  20 , thus to apply a braking action for the device. 
   Note that the areas of piston seals  55 ,  56  are the only location where significant axial movement of two adjoining parts is maintained. As the swept area in the preferred device has both locations on the outer circumferential of a single part, manufacturing can occur at a single grinding location. This reduces the cost of the device. (Since the piston seals  55 ,  56  are reset into grooves in the piston  57 , the piston can be turned.) Note also that it is possible to assemble the piston  57  and reaction support member  51  together for later incorporation as an integral unit into the remainder of the device  10 . This allows the premanufacture of this unit in one location (preferably along with seal  46 ) with integration to the remainder of the device occurring in another less precise location; all important seals  65 ,  66  (and  46 ) are physically protected. The locations can be very remote or even across the country from each other. This is aided by the fact that except for these parts the other dimension that should be held is the outer surface of the reduced oil passage section  45  of the spindle  20 . 
   The spinner nut locking member  80  serves a dual purpose of assisting in the weight loading from the wheel  100  and the housing  60  to the exterior surface of the reaction support member  51  (which then passes along to the spindle  20  through bearing  41 ). The spinner member  80  thus functions as an integral weight transfer process. The spinner member  80  in addition also axially pressure preloads the inner edge of the disk spring  59 . This provides the engagement forces for the braking mechanism  50 . Note that it is preferred that the spinner nut  80  in contact with the adjacent shoulder  53  of the reaction member  51  to provide for a reliable braking force across individual units within any series of devices  10 . Note that it is preferred to assemble the entire device before adding the spinner nut. Assembly can thus occur with hand tools without regard for the loading of the spring  59 . The spinner nut can then be included with a spanner wrench. (The screw threads outside the nut would provide the leverage to compress the spring  59 .) 
   The housing  60  serves to contain the spindle  20  and braking mechanism  50  in addition to providing an integral weight transferring hub for the tire  100 . 
   In respect to containing the braking mechanism  50 , the wheel  100  is substantially the same inner and outer diameter and width as it would be without such mechanism. This allows a given manufacturer to produce both braked and unbraked designs with a single frame. This would include other parts associated with the frame as the main addition to unbraked units is the addition of pressure line  205 . 
   In respect to the transfer of weight, the housing  60  shown is primarily made of two cylindrical plates  62 ,  63  and a surrounding hub  64 . In the embodiment shown, all of these pieces are integrally interconnected together via a series of hex screw bolts  70  that extend circumferentially about the device from both ends. 
   The inner cylindrical plate  63  of the housing is interconnected to the spindle  20  directly through the main bearing  31 . The fact that all pieces are radially aligned facilitates the weight transfer between the parts, enabling them to function as a single unitary piece. Due to this bearing and the existence of snap rings  35  (one internal, one external), this cylindrical plate  63  of the housing is not able to shift axially of the device. As the other housing parts  62 ,  64  are integrally connected to this plate  63 , the plate  63  thus serves as the primary retention mechanism between the spindle and the remainder of the brake assembly  50 . 
   The outer cylindrical piece  63  passes its forces through the spinner nut locking member  80  which is itself securely interconnected through the reaction support member  51  to the inner bearing  41 . This allows forces on the outer end of the assembly to pass through the needle bearing  41  into the secondary bearing area  40  of the fixed spindle  20 . 
   The tire  100  completes the assembly  10 . This tire  100  is directly interconnected to the housing  60  so that this housing serves as a hub for the tire. This allows the assembly  10  to have a smaller diameter and less complicated construction than with the alternative of a separate wheel hub. 
   Note that the load of the tire  100  surrounds the two bearings  31 ,  41 . The radial transfer of forces between the two is thus readily accomplished. Further, since virtually all of the brake mechanism  50  rotates at the same time and at the same speed of the tire  100  there is no need for complicated fluid passages or seals: the dynamic seal  46  provides for substantially all of the rotational movement between adjoining parts in the device. The remaining seals are static seals (mostly relative to the housing  60 , reaction support member  51 ), or subject to small movements under limited condition (the piston seals  55 ,  56  during a transition between the two operating states of the brake—on or off). 
   The particular preferred embodiment has a tire  100  substantially 12″ in diameter and 4.3″ in width. The total unit is 5″ wide including spindle plate  21 . The tire has a depth of 1+¾″ to the outer diameter of the housing  60 . The support piston  57  has a hydraulic cavity  54  with an outer diameter of 5+⅜″ and an inner diameter of 3+⅛″. The reduced oil passage extension  45  of the piston has a diameter of 0.5″. The disk spring  59  is 6″ in diameter with an initial depth of 0.38″. It develops substantially 500000 pounds of force at 0.09″ deflection. 
   The preferred embodiment of the invention discloses a method of manufacture including preassembly of the reaction member and piston, the loading of the spring by the spindle nut, the multi-piece housing, and the modifications of the spindle mounting plate to accomplish differing frames. The use of a novel seals (only three seals between moveable parts) and the reduced sized oil passage extension simplify and lengthen the service life of the assembly. The availability of room about the outer end of the spindle for the brake and the use of the intermediate reaction support member shorten the unit to substantially the width of the surrounding tire. The oil passage is simple through the spindle, with a double back path to the brake piston cavity. The total unit can be used without the brake package without structural modification. A single ball bearing serves as a main bearing as well as the thrust bearings. It is further possible to remanufacture the device from one end. 
   Note that due to the simplicity of the structure of the brake assembly, alternate applications can be readily handled by a single design. For example, the spindle mounting plate  20  serves to integrate the brake assembly  10  with its associated device. It is a fairly easy matter to design and make differing spindle mounting plate  21  to provide for a wide number of differing applications with a basic single device. Further, maintenance of the device is facilitated: by removing the spinner nut locking member  80  and the outer hex screw bolts  70  it is possible to entirely disassemble the braking mechanism to replace any pressure components or disk components therein without significant compromise to the overall structural strength of the device once reassembled. Additional example, the moving parts of the brake (disks  33 ,  58 ; piston  57 ; disk spring  59 ; and, seal  46 ) can be entirely omitted without structural compromise to the tire/spindle weight supportive rotary interconnection. Therefore, although the invention has been described in its preferred form with a certain degree of particularity, it is to be understood that modifications can also be made without deviating from the invention as hereinafter claimed.