Abstract:
A hair ingestion device and dust protector for a vacuum cleaner, and a combination of an end cap and a dowel assembly having a thread cap, wherein a set of arms extends from the thread cap for rotating with the dowel for deflecting threads to avoid contamination of the bearing assembly included in the dowel assembly. The thread cap also includes tapered vanes for cooperating with an end cap to form a dust shield.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to apparatus for a vacuum cleaner and, in particular, to a cap or to structure integral with the dowel for preventing threads and other thin items such as both hair and dust from reaching the bearings of a vacuum cleaner and damaging the bearings and the vacuum cleaner itself, and for preventing threads, hair and fibers from clogging or seizing the rotation of the dowel which rotates in the head of the vacuum cleaner.  
         [0003]     2. Description of the Prior Art  
         [0004]     Various items are known for preventing or at least reducing contaminants from reaching the bearings of a vacuum cleaner, these bearings often being carried by the dowel assembly of a vacuum cleaner, where the dowel assembly includes a dowel which rotates about its longitudinal axis. The bearings can be of many types, such as ball bearings or bushings, and other friction reducing means. In a popular version of a vacuum cleaner, the dowel has radially extending tufts of bristles or the like, and the dowel assembly is rotated by means of a belt which is driven by the vacuum cleaner motor. In another version, the dowel assembly is rotated by a motor-driven gear chain. Some of the persistent contaminants of vacuum cleaner bearings are thread, hair, fibers and the like (hereinafter sometimes referred to as “thread”). One attempt to prevent thread from reaching the bearings is the provision of felt on the ends of the dowel, which acts as a barrier to block some thread from passing to the bearings and/or from clogging the dowel. However, the felt has been found to simply accumulate thread, and some thread either breaks from being held by the felt or passes through the felt and is carried to the bearings and/or may contribute to seizing the dowel. Another attempt to keep thread from moving to the bearings or clogging the dowel is a cylindrical wall which extends from a disk overlapping the end of the dowel assembly and extends toward the center of the dowel assembly for acting as a shield or labyrinth for barring the threads from reaching the bearings or clogging the dowel. However, this type of shield is not effective since potentially damaging threads bypass the cylindrical wall.  
         [0005]     The thread problem is serious in the vacuum cleaner industry, and various companies have established hair ingestion tests in which particular amounts of hair are spread over a prescribed area. In order to pass the test, a vacuum cleaner is required to prevent the operating vacuum cleaner from picking up the hair and transferring it into the bearing assembly and/or clogging the dowel in the end of the dowel assembly. Passing these tests has been a serious problem in the vacuum cleaner industry.  
         [0006]     The problem of dust invading the end of the dowel of a vacuum cleaner and potentially causing damage to the bearings was solved as set forth in Ser. No. 10/375,747 filed Feb. 26, 2003 by the present inventors. In the preferred embodiment of that application, a set of vanes rotating with the dowel cooperate with an appropriately configured end cap to in effect set up an air barrier while expelling dust in the vicinity.  
       SUMMARY OF THE INVENTION  
       [0007]     An object of the present invention is to provide an improved apparatus for protecting a vacuum cleaner from contaminants.  
         [0008]     Another object is to protect a vacuum cleaner from threads.  
         [0009]     Still a further object of the invention is to prevent threads from damaging the bearing assembly of a vacuum cleaner.  
         [0010]     It is a further object to prevent threads from clogging or seizing a dowel in vacuum cleaners.  
         [0011]     It is an additional object to protect the bearing components held in the dowel assembly of a vacuum cleaner from threads.  
         [0012]     Yet still another object is to provide apparatus for substantially preventing threads from contaminating the bearings in the dowel assembly of a vacuum cleaner.  
         [0013]     It is also an object to provide apparatus for preventing threads from impairing the operation of bearing assemblies in vacuum cleaners, which apparatus is economical to fabricate and install, and effective in use.  
         [0014]     Another object is to provide a device for effectively and efficiently preventing hair and dust from contaminating the bearings and/or from clogging the dowel of a vacuum cleaner.  
         [0015]     An additional object is to provide an improved device for both preventing threads from impairing the operation of a vacuum cleaner and for preventing dust from also preventing the proper operation of a vacuum cleaner.  
         [0016]     These and other objects will become apparent from the description to follow and from the appended claims.  
         [0017]     The foregoing objects of the present invention are achieved by the preferred embodiment of the invention. Many vacuum cleaners incorporate a dowel assembly having a dowel with tufts of bristles extending generally radially therefrom for picking up dirt, including dust and thread, as the dowel rotates about its central, longitudinal axis. An axially-extending rod extends from each end of the dowel portion of the dowel assembly, and the dowel rotates with the rod(s). The dowel assembly is rotated by a belt, gear train or the like, which is driven by a motor. The dowel assembly has a dowel which is usually recessed at its opposite ends. A bearing assembly is located in the respective recesses, and the bearing assembly engages both the rod(s) during rotation of the dowel and structure fixed relative to the body of the vacuum cleaner, such as an end cap, for reducing friction between the dowel and the fixed structure. The end cap covers an end of the dowel assembly and has an inner collar configured to fit into the recess and to engage the fixed portion of the bearing assembly. The hair (or thread) ingestion device and dust protector according to the preferred embodiment includes a thread cap. The thread cap is seated inside each recess of the dowel and sits against an end wall of the dowel perpendicular to the longitudinal axis of the dowel. The thread cap has an annular shoulder for locating the bearing assembly which is mounted on the rod. The thread cap has an annular flange from which extend radial arms. The radial arms can lie in a common plane which is perpendicular to the longitudinal central axis of the dowel. The arms may also be referred to as skirts, tangs or deflector paddles. Each arm is defined on its radial sides by a pair of generally radial edges which are referred to herein as ramps. The respective arms are separated by a space having no arms, the spaces being referred to as “slots.” The arms set up a barrier to prevent thread from moving to the bearing assembly. The number of arms is not crucial, but an inventive end cap with eight arms has been found to be very effective.  
         [0018]     The thread cap has a generally frusto-conical wall defining a recess, and generally radial vanes extend from the latter wall into the recess. The outer walls of the collar of the end cap cooperate with the vanes to form a dust protector.  
         [0019]     Alternatively, the foregoing structure could be incorporated as an integral part of the dowel, or as a separate piece or pieces attached to the dowel. Likewise, some components could be integral with the dowel, and others could be part of an insert in the dowel.  
         [0020]     The dowel assembly rotates about its central axis as it is driven by the driving assembly operated by the vacuum cleaner motor. The rotating deflector arms or paddles, accompanied by the slots, deflect threads and prevent the threads from entering the recesses at the end of the dowel assembly and stop the threads from reaching the bearing assembly or from clogging (i.e. seizing) the dowel. The vanes cooperate with the collar of the end cap to establish an air shield transverse to the longitudinal axis of the dowel and to apply centrifugal force to dust particles to drive them from the recess in the dowel and to the ambient atmosphere. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a part perspective view of a dowel assembly for a vacuum cleaner, showing an end cap with a portion cut away to show a portion of the invention.  
         [0022]      FIG. 2  is a side view of the apparatus shown in  FIG. 1 .  
         [0023]      FIG. 3  is a perspective view of a thread cap according to a preferred embodiment of the invention.  
         [0024]      FIG. 4  is an alternate thread cap according to the invention.  
         [0025]      FIG. 5  is a cross-sectional view of a dowel assembly with a thread cap as shown in  FIG. 3 , and an end cap.  
         [0026]      FIG. 6  is a bottom view of a portion of a vacuum cleaner with a dowel assembly and end caps incorporating the present invention. The cover of the vacuum cleaner has been removed to reveal the foregoing parts. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]     Referring first to  FIG. 1 , one end portion of a dowel assembly  10  is shown on which is mounted an end cap  30 . Dowel assembly  10  incorporates a dowel  12 . Dowel  12  is shown as being belt driven and has a pair of annular recesses  14  with radial sidewalls  16 , 18  to collectively form a pulley  19  having a rim  21  for receiving a motor driven drive belt. An annular side end portion  20  of dowel  12  has generally radial tufts of bristles  22  extending therefrom for picking up such dirt as dust and threads coming in their path as dowel  12  is rotated by the vacuum cleaner motor. Tufts of bristles  22  are of a type known in the art. The portion of the dowel assembly is shown in  FIG. 1 , and the opposite end is nearly identical in configuration and components, although usually only one part of the assembly is provided with the structure for rotating the dowel.  
         [0028]     Dowel  12  rotates about a rod or shaft  24  running along the central longitudinal axis of dowel  12 . Rod  24  could extend through the entire length of dowel  12  through a bore  26  extending along the length of dowel  12 , or there could be a pair of rods which is disposed at an axial end of dowel  12 , in which case bore  26  would be closed to properly locate each rod  24 . Dowel  12  and rod(s)  24  are fixed to each other. A thread cap  28  is mounted on the free end of rod  24  extending from a recess in dowel  12  as explained below, and end cap  30  covers the end of dowel assembly  12 . As explained later, end cap  30  functions both as a contributing part of a dust shield and as a bearing assembly holder. A bearing assembly  32  is also mounted on the end portion of rod  24  as also discussed below, and end cap  30  has a cylindrical inner collar  34  which engages bearing assembly  32  to hold one part as discussed later. End cap  30  has an outer cylindrical wall  36  which helps to prevent dust from entering the end portion of dowel assembly  10 . End cap  30  is fixed relative to the body of the vacuum cleaner in which dowel assembly  10  is mounted.  
         [0029]     The side view of  FIG. 1  is shown in  FIG. 2 .  FIG. 2  shows one end part of dowel assembly  10  with dowel  12 , annular recess  14  with sidewalls  16 , 18 , annular side end portion  20  and tufts of bristles  22 . The side of thread cap  28  is shown. End cap  30  covers the end portion of dowel assembly  10 .  
         [0030]     Thread cap  28  is shown in detail in  FIG. 3 . Thread cap  28  comprises a support  29  which is generally frusto-conical in shape, having a frusto-conical wall  39  tapering outwardly from a relatively small in diameter inner hub  40  to the relatively large inside circular portion or inner edge  42  of an annular flange or support  44 . Hub  40  has a hole  43  for fitting over rod  24 . Thread cap  28  has an inside surface or inner end wall  41  being seated in the recess of dowel  12  and a bearing seating surface  45  upon which a bearing assembly can be seated. Thread cap  28  incorporates a set of vanes  46  extending along the inner surface of frusto-conical wall  39  for cooperating with collar  34  of end cap  30  to prevent dust from contaminating bearing assembly  32  (as described in principle in co-pending U.S. Ser. No. 10/375,747 filed Feb. 26, 2003 cited above), although in the latter application the vane structure is on the dowel and not on a thread cap as is presently being discussed. Vanes  46  extend radially inwardly from wall  38  and are inclined outwardly from the outer edge of hub  40  to the inner edge of flange  44  to set up an air movement which both bars dust from moving towards hole  43  and bearing assembly  32 , and for establishing a centrifugal force to eject dust from between thread cap  28  and end cap  30  to the ambient air. Eight vanes  46  have been found to work well, but other numbers may work as well. There may be situations where vanes  46  are not required, and they could be removed; however, arms  46  will function according to the invention. The structure without the vanes is shown in  FIG. 4 .  
         [0031]     Referring to  FIG. 5 , collar  34  has an outer (away from the longitudinal axis of end cap  30 ) wall  47  which is inclined by the same amount as vanes  46 , but collar  34  terminates in the radial direction prior to its entering the space between vanes  46 . Wall  47  defines a volume with the interior of thread cap  28  with vanes  46  for establishing a dust or air shield to prevent dust from flowing to the bearing assembly and for defining a path for the dust to be forced from the dowel assembly and the end cap by centrifugal force.  
         [0032]     However, whereas the flange corresponding to flange  44  in  FIG. 3  in Ser. No. 10/375,747 is relatively narrow, flange  44  is wider and it carries radially-extending angularly (and preferably equiangularly) spaced arms  48 . Each arm  48  is defined on its generally radially oppositely disposed sides by ramps  50 , 52  and at its free end by an outer edge or free end  54 . Ramps  50 , 52  are angled to prevent threads from clogging or seizing the rotation of dowel  12 , or contaminating the bearing assembly. Viewing  FIG. 3 , when thread cap  28  rotates clockwise as shown by arrow A, threads moving between any of ramps  50  and  52  are engaged by ramp  52  and deflected in direction C generally parallel with the axis of rotation of dowel  12  and away from the bearing assembly. Likewise, when thread cap  28  is rotating counterclockwise in Direction B, threads are engaged by a ramp  50  and also deflected in direction C away from the bearing assembly. The angle θ of ramps  50 , 52  should be between 30°-60°, although other angles and configurations are within the scope of the invention. For example, θ could be 0°, the ramps could each have a variety of configurations within each ramp, and each pair of ramps facing each other could have different configurations. The depth of arms  48  depend upon the nature of the dowel assembly, the characteristics of thread cap  28 , the nature of the threads expected to be encountered, and other variations depending on the nature of the vacuum cleaner. Moreover, arms  48  need not extend radially from outer end  53  of thread cap  28 .  
         [0033]     Still considering arms  48 , each arm  48  extends from an outer end  53  of thread cap  28 , outer end  53  being nearest the end of dowel  12  when inner hub  40  at an inner end  55  is inserted into the end portion of dowel  12 . Flange  44  is at outer end  53 . Free ends  54  lie in an imaginary cylindrical surface concentric with the axis of dowel  12 , with each end  54  being partially concentric with that axis. Ramps  50 , 52  are therefore concentric with the axis of dowel  12  and are inclined inwardly from outer end  53  towards inner end  55 . In other words, the projection of ramps  50 , 52  on the respective arms  48  would meet in the direction of the inner end  55  of end cap  28 . Edges  54  are preferably curved and concentric with the longitudinal, central axis of bore  26 . Flange  44  and arms  48  are advantageously planar, and the plane is perpendicular to the axis of bore  26 .  
         [0034]     Inner hub  40  of thread cap  28  includes bearing seating surface  45  for seating bearing assembly  32  in the recess of dowel  12 . Surface  45  is on a relatively thick inner cylindrical part for providing strength to thread cap  28  as well as to provide an increased area of thread cap  28  for the rod in the dowel to engage.  
         [0035]      FIG. 5  shows the invention in a slightly different, but similar, dowel assembly  100  for a vacuum cleaner. The same numerical designators will be used as in  FIGS. 1 and 2 , but a different pulley  60  is used and cutting channels are incorporated as explained below. Pulley  60  is fixed in dowel  12 , which is engaged by a belt driven by the motor for the vacuum cleaner to rotate dowel  12  about rod  24 . The end of dowel  12  as shown includes tapering sidewall  62  and an end wall  64 , for defining a recess in the end of dowel  12  (there are like structures at both ends of dowel  12 ). Bore  26  extends through dowel  12  to accommodate rod  24  which rotates with dowel  12 . Dowel  12  further includes cutting channels  66 , 68  in which scissors or other cutting device can be inserted to cut thread wound about dowel  12  to facilitate removal of the thread.  
         [0036]     Bearing assembly  32  is a ball bearing assembly (although other bearing assemblies such as bushings could be used) and is composed of an inner ring or race  70  having an axial hole with an inner diameter generally equal to the diameter of rod  24  so that ring  70  will rotate with rod  24 , an outer ring or race  72  with an outer diameter, and a set of bearing balls  74 . Inner hub  40  of thread cap  28  has bearing surface  45 , and inner ring  70  sits on surface  45 . As discussed below, outer ring  72  is fixed with respect to end cap  30 .  
         [0037]     Thread cap  28  is shown as being seated in the recess in the end of dowel  12 . Wall  39  of thread cap  28  and tapering sidewall  62  of dowel  12  are configured to nest together. Thread cap  28  has its inner end wall  41  which is seated against end wall  64  of dowel  12 . Thread cap  28  is shown having inwardly extending vanes  46  and outwardly extending flanges  44  with arms  48 .  
         [0038]     End cap  30  is mounted across the end of dowel assembly  100  and has protrusion  76  having an inner recess defined by inner cylindrical wall  78  and inner protrusion end wall  80 . Protrusion  76  receives the end of rod  24 . End cap  30  further has an inner shoulder  82  engaging the end of outer ring  72  of bearing assembly  32 . Collar  34  has an interior bore  84  for engaging outside surface  86  of bearing assembly  32  by means of a press fit. By this arrangement, the rotation of dowel  12 , rod  24 , thread cap  28  and inner ring  70  is effected, and end cap  30  and outer ring  72  of bearing assembly  32  are stationary with respect to the foregoing rotation.  
         [0039]     Dowel  12  is preferably made by injection molding of an appropriate plastic, although wood or metal could also be used. Injection molding is advantageous in that it provides fast, consistent results and yields a product of even density that may not require rotational balancing. Thread cap  28 , end cap  30  and pulley  106  shown in  FIG. 5 , are also preferably made from an appropriate plastic by injection molding, and various pulley designs are possible depending on the driving device. Appropriate plastics include nylon, glass-filled nylon, ABS and the like. Metal pulleys are also possible.  
         [0040]      FIG. 6  shows a dowel assembly  100  with end caps  30  mounted in a vacuum cleaner  102 . Dowel assembly  100  is rotated by a belt  104 . Belt  104  is rotated by a shaft  106  which is rotated by the vacuum cleaner motor. Tufts of bristles  22  perform the cleaning operation. End caps  30  are fixed relative to the body of vacuum cleaner  102  by means of sole plates  108  which fixedly engage protrusions  76  of end caps  30 . While dowel  12  is shown as being rotated by belt  104 , other means for rotating a dowel are known. In addition to a gear train mentioned earlier, the dowel could be rotated by airflow, a motor within the dowel, a worm gear, an electrical device or by a shaft.  
         [0041]     In operation, dowel  12  is rotated about its longitudinal axis by the drive belt  104 , gear drive or the like. Considering first the threads which could damage bearing assembly  32 , thread cap  28  rotates with dowel  12 . Radially-extending arms  48  deflect threads, which might otherwise work their way between end cap  30  and bearing assembly  32 , and prevent them from damaging the bearing assembly. The deflected threads may be wound about dowel  12  or may be deflected entirely away from the vacuum cleaner.  
         [0042]     Turning to the dust, the rotation of thread cap  28  establishes air turbulence in a cavity  86 , around the inner portion of collar  34  to its termination at outer cylindrical wall  36 . This turbulence provides a barrier to dust which otherwise could flow through the cavity and contaminate the bearing assembly. Any dust that happened to be in or around the bearing assembly would be expelled by centrifugal force.  
         [0043]     The invention thus provides a very effective yet inexpensive way to prevent both threads and dust from contaminating the bearing assembly. The invention can be made through injection molding of appropriate plastics using known manufacturing techniques. Plastic has been found to be a preferable material, but other materials such as metal, wood, glass fibers and the like could also be used. Although the preferred embodiment of the invention showed the arms and vanes as being part of the thread cap, the invention also encompasses the arms and/or vanes being integral with the dowel.  
         [0044]     The invention has been described in detail, with particular emphasis on the preferred embodiments thereof, but variations and modifications may occur to those skilled in the art to which the invention pertains from the foregoing specification and drawings, and the appended claims.