Abstract:
A wheel is for use in manually turning a shaft on rolling stock, such as for a handbrake. The wheel has a hub and a rim. The hub is made of a first material and has an opening that is structured and arranged to receive the shaft. The opening has a rotational axis. The hub has an exterior around the rotational axis, with the hub having drive surfaces relative to the rotational axis. The rim is coupled to the hub so as to engage the drive surfaces. The drive surfaces include flat surfaces and corners of a tube portion of the hub, a radially extending plate with holes therethrough and teeth in an outer edge and gussets coupled between the tube portion and the plate. The rim has an outer periphery structured and arranged to be gripped by a human hand for rotating the wheel. The rim is made of a second material that is softer than the first material.

Description:
This application claims the benefit of provisional patent application Ser. No. 60/649,667, filed Feb. 3, 2005. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to handbrake systems for rolling stock, and in particular to the wheels used to set and release the handbrakes. 
     BACKGROUND OF THE INVENTION 
     Rolling stock includes locomotives and freight cars. In general, rolling stock vehicles are equipped with handbrakes, which are brakes that can be set manually. The handbrake of a rolling stock vehicle is set and released by turning a wheel on an end of the stock. The wheel is mounted on a shaft. 
     Handbrakes are used, for example, when one or several vehicles have been uncoupled from a locomotive. The handbrakes are set by crew members to prevent the rolling stock from moving on the tracks. 
     Prior art handbrake wheels are made of metal, a design that has remained unchanged for about a century. The handbrake wheel is made of stamped steel and has a cast iron center, which center has a square opening for receiving the shaft. 
     One problem with the metal wheel is that a crew member can sustain a hand injury if not wearing gloves. The steel on the wheel is unfinished and offers sharp or rough edges, including burrs. 
     Another problem with the metal wheel is the weight. Metal wheels are heavy. As the car moves along the track, the wheel vibrates on the shaft. Because the wheel is mounted at the end of the shaft, bearings that support the shaft are subjected to wear and premature failure. Because of the heavy vibrational load, handbrake wheel manufacturers are unwilling to provide long warranties on the handbrakes. 
     An Australian company developed an all-plastic handbrake wheel. The wheel was monolithic, made of the same plastic throughout. However the wheel exhibited failure, cracking in the center. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a wheel for rolling stock that is lighter in weight than the prior art wheel. 
     It is another object of the present invention to provide a wheel for rolling stock that minimizes the risk of injury to operators. 
     The present invention provides a wheel for use in manually rotating a shaft on rolling stock. The wheel has a hub and a rim. The hub is made of a first material and has an opening that is structured and arranged to receive a shaft. The opening has a rotational axis. The hub has an exterior around the rotational axis. The hub exterior has drive surfaces relative to the rotational axis. The rim is coupled to the hub so as to engage the drive surfaces. The rim has an outer periphery structured and arranged to be gripped by a human hand for rotating the wheel. The rim is made of a second material that is softer than the first material. 
     In accordance with one aspect of the present invention the hub comprises a tube portion incorporating the opening. The tube portion has at least some of the drive surfaces in the form of flat surfaces forming a polygon when viewed in cross-section along the rotational axis. A plate extends radially from the tube portion. The plate has other of the drive surfaces. The tube portion and the plate are encompassed by the rim. 
     In accordance with another aspect of the present invention the plate comprises holes therethrough. The holes comprise the other of the drive surfaces. 
     In accordance with still another aspect of the present invention the wheel further comprises gussets coupled between the tube portion and the plate. The gussets form still others of the drive surfaces. 
     In accordance with still another aspect of the present invention the hub is made of metal and the rim is made of plastic. 
     In accordance with still another aspect of the present invention the hub is made of a first plastic and the rim is made of a second plastic. 
     In accordance with still another aspect of the present invention the rim comprises an outer rim having the outer periphery and a central area. The outer rim is coupled to the central area by spokes. 
     In accordance with still another aspect of the present invention the plate comprises teeth around an outer edge of the plate, the teeth comprise the other of the drive surfaces. 
     In accordance with still another aspect of the present invention the plate comprises holes therethrough, which holes comprise the other of the drive surfaces. Gussets are coupled between the tube portion and the plate, which gussets form still other of the drive surfaces. 
     In accordance with still another aspect of the present invention the plate comprises teeth around an outer edge of the plate, the teeth comprise the other of the drive surfaces. Gussets are coupled between the tube portion and the plate, which gussets form still other of the drive surfaces. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of an end of a rolling stock car, showing a handbrake wheel. 
         FIG. 2  is a side elevational view of the car of  FIG. 1 . 
         FIG. 3  is an isometric view of front side of the handbrake wheel of the present invention, in accordance with a preferred embodiment. 
         FIG. 4  is an isometric view of the back side of the handbrake wheel of the present invention. 
         FIG. 5  is a side elevational view of the handbrake wheel. 
         FIG. 6  is an isometric view showing the back side of the center insert of the wheel. 
         FIG. 7  is another view showing the opposite, or front, side of this center insert that is shown in  FIG. 6 . 
         FIG. 8  is an elevational view of the center insert. 
         FIG. 9  is a plan view of the back side of the center insert. 
         FIG. 10  is a cross-sectional view of the center insert, taken through lines X-X of  FIG. 9 . 
         FIG. 11  is a cross-sectional view of the wheel, taken through lines XI-XI of  FIG. 3 . 
         FIG. 12  is a plan view of the wheel of the present invention, in accordance with another embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The wheel of the present invention can be used on all types of rolling stock  11 . By way of example, the handbrake end (the “B-end”) of a typical rolling stock car assembly to which the present invention is applied is illustrated in  FIGS. 1 and 2 . The car is provided with a conventional semi-automatic coupler  13  and a truck  15 . The truck  15  carries a body bolster  17  between frames  19 , which frames support the center sill  21 . The wheels  23  are rotatably coupled to the frames  19 . 
     The end of the car is provided with a conventional handbrake. The handbrake has a wheel  31  mounted to a shaft  33  which shaft is received in a vertical bracket  35 . The end of the shaft  33  is threaded and protrudes through the wheel  31  to receive a washer and nut (not shown). The nut secures and retains the wheel  31  onto the shaft  33 . 
     An operator grips the outer rim and turns the wheel  31  to set or release the brake. Turning the wheel  31  in one direction sets the brake; turning the wheel in the opposite direction releases the brake. 
     In the description that follows, the terms “front side” and “back side” are used with reference to the orientation of the wheel as seen by an operator who is gripping the wheel to turn it. The front side faces the operator, while the back side faces away from the operator. 
     The handbrake wheel  31  of the present invention is shown in  FIGS. 3-5 . The handbrake wheel  31  is made of plastic, with the exception of a metal center insert, or hub,  37 . The center insert  37  has a square opening  39  for receiving the shaft  33  (shown in  FIGS. 1-2 ). 
     The wheel  31  has a rim  40  which surrounds the center insert  37  and makes up the remainder of the wheel  31 . In one embodiment, the rim  40  has an outer rim  41  and an intermediate rim  43  spaced between the outer rim and a central area  45 . The outer rim  41  and intermediate rim  43  are connected by outer spokes  47 . The intermediate rim  43  is connected to the central area  45  by inner spokes  49 . As shown in  FIGS. 3 and 5 , the outer and intermediate rims  41 ,  43  are coplanar, while the central area  45  is offset from the rim plane. 
     In another embodiment, the openings between the inner spokes are removed so as to form a solid member from the central area  45  to the intermediate rim  43 . This embodiment replaces the spokes  49  with solid plastic. In still another embodiment, the openings between the outer spokes  47  are removed so as to form a solid member from the central area  45  to the outer rim  41 . This embodiment replaces the spokes  47 ,  49  with solid plastic. 
     The center insert  37  is shown in  FIGS. 6-10 . The opening  39  has a rotational axis  50 , which is the axis of rotation of the shaft  33 . The center insert  37  has a polygonal body  51 , when viewed in cross-section along the axis  50 . The body has rounded corners  53 . In the preferred embodiment, the body is rectangular. The opening  39  tapers in longitudinal cross-sectional area (see  FIG. 10 ), becoming larger from the front side to the back side (see  FIG. 11 ). The wall thickness of the body  51  decreases from the front side to the back side. A plate  55  is provided adjacent to the front end of the body  51 . The plane of the plate  55  is transverse to the axis  50 ; thus the plate extends radially out from the body  51 . Gussets  57  are provided to reinforce the coupling of the body  51  to the plate  55 . There is a gusset  57  on each side of the body  51 . The plate  55  is provided with holes  59  therethrough. The holes  59  are spaced between the gussets  57 . The plate  55  has an outer edge  63 . The outer edge  63  of the plate has teeth  61 , which teeth increase the surface area of the edge  63 . The combination of the corners  53 , the gussets  57 , the plate holes  59  and the plate outer edge teeth  61  significantly increase the shear strength between the insert  37  and the rim. 
     The body  51  has an end surface  67 . The center insert has another end surface  69  opposite of the body end surface  67 . The end surface  69  is incorporated into a boss  65  that protrudes from the plate  55 . 
     The center insert  37  is a one-piece cast member. In the preferred embodiment, the center insert is made of aluminum, although other metals can be used. The rim is made of plastic, such as high density polyethylene (HDPE). 
     To make the wheel, the center insert  37  is placed in a mold, such as an injection mold. The plastic rim  40  portions of the wheel (the rims  41 ,  43 , the central area  45  and the spokes  47 ,  49 ) are molded around the center insert. The center insert  37  is entirely contained within the central area  45  of the plastic portion of the wheel, with the exception of the end surfaces  67  and  69  as shown in  FIG. 11 . The plate  55  is set off from the end surface  69  by the boss  65 . 
     The wheel  31  is mounted to the shaft  33 . A washer contacts the end surface  69  and a nut threads onto the shaft to secure the wheel to the shaft. 
     In use, the handbrake wheel  31  is turned only occasionally. The wheel  31  is on the end of the shaft  33 . Because the wheel  31  is non-metal, the wheel is lighter than the prior art metal wheel. In the preferred embodiment, the wheel weighs only 4½ pounds. The prior art wheel weighs 14½ pounds. The lighter wheel presents a lower load on the shaft bearings as the rolling stock is moving, resulting in longer bearing life. 
     When the wheel  31  is turned, the force applied to the rim  40  is transferred to the center insert  37  and the shaft  33 . The center insert  37  is strongly coupled to the plastic central area  45  of the wheel. When the wheel  31  is turned so as to rotate the shaft  33 , shear forces will be applied to the coupling between the center insert and the plastic component of the wheel. The center insert  37  resists the shear forces with the corners  53  on the body  51 , with the gussets  57 , with the holes  59 , which receive plastic during the molding process, and with the edge surfaces  61 ,  63  of the plate outer edge. Thus, the center insert  37  is securely coupled to the central area  45  of the plastic wheel and will exhibit a long life in use. The sides of the body  51  can be etched or grooved to increase the bonding of the body with the rim  40 . 
       FIG. 12  shows another embodiment of the wheel  31 A. The inner spokes  49 A between the central area  45 A and the intermediate rim  43 A are formed by circles  81  and form a strong and sturdy wheel configuration. 
     The wheels  31 ,  31 A are known as “shallow dish” wheels. As shown in  FIG. 11 , the center insert  37  is offset from the outer rim  41 . The offset is longitudinal relative to the shaft longitudinal axis. The offset can be increased to provide a “deep dish” wheel. Such a deep dish wheel is preferred where the wheel is installed subject to an obstruction, such as a ladder or platform. The offset provides clearance for the wheel rims from the obstruction. Either wheel  31 ,  31 A can be provided with a deeper offset. 
     Also, the wheels  31 ,  31 A can have roughened gripping surfaces. The outer rims  41 ,  41 A and outer spokes  47 ,  47 A can be roughened to increase the grip of an operator&#39;s hand and reduce the tendency of the hand to slip on the wheel. As shown in  FIG. 12 , roughening can occur by providing bosses or ribs  83 . The ribs  83  are located on the outer rim  41 A between the spokes  47 A. The ribs are located on both the front side and the back side of the outer rim. An operator&#39;s fingers grip the outer rim  41 A at these locations. The fingers fit between the ribs  83 . Also, a diamond pattern is formed on the outer rim  41 A between the ribs  83  and on the outer spokes  47 A. The other surfaces of the outer rim and outer spokes are roughened with a grit texture, for example such as an  80  grit surface. The roughened surfaces are part of the mold so as to be incorporated into the wheel during the molding process and reduce post-molding processing. Even with the roughened gripping surfaces, the wheel  31 ,  31 A lacks the burrs and sharp edges of the prior art metal wheel, thereby reducing the risk of injury to an operator&#39;s hands. 
     Although the center insert  37  has been described as being made of metal, it could be made of plastic for an all-plastic wheel, or it could be made of some other material. The center insert  37  is made of a harder material than the rim  41 . Because the center insert  37  contacts the shaft  33 , it must be sufficiently hard to engage the shaft and turn the shaft without stripping or wearing. However, hard materials are typically more brittle than softer materials. The remainder of the wheel, namely the rim, is made of a softer material so as to make the wheel less brittle and stronger. 
     Examples of plastic materials for the center insert  57  are reinforced nylon (PA), polyphelene oxide (PPO), polyethermide (PEI), polyphthalamide (PPA), phelene (PPE), liquid crystal polymer (LCP), polyaryletherkeytone (PAEK), polyetherketoneetherketoneketone (PEKEKK), polyetheretherketone (PEEK), and metal injection molding (MIM). The center insert can be made of fiber filled (such as carbon fiber) plastic. 
     Although the present invention has been described in conjunction with handbrake wheels, the wheel can be used in other applications on rolling stock. For example, many railroad cars have plug doors. The plug doors are opened with handles or bars. One problem with opening the plug door using a handle or bar is that when an operator tries to open the door, the handle or bar can snap back and spin, causing injury to the operator. 
     The wheel of the present invention can be retrofitted on to the shaft by removing the handle or bar and replacing it with the wheel. Thus, the wheel can be used to open and close plug doors on rolling stock. 
     The foregoing disclosure and showings made in the drawings are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense.