Patent Publication Number: US-2005134140-A1

Title: Motor mounting base

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is a continuation of prior application Ser. No. 10/072,200, filed Feb. 7, 2002. 
    
    
     FIELD OF THE INVENTION  
      The invention involves a motor mounting platform in general, and in particular, a motor mounting platform that utilizes commutator brush holders.  
     BACKGROUND OF THE INVENTION  
      The mounting of the motor within an electrical appliance such as vacuum cleaner requires a manufacture to satisfy various safety requirements. This is because as the power source for the appliance, the motor generates electrical current that must be insulated from other components in order to prevent the risk of fire.  
      Currently, motors are mounted in electrical appliances through the use of mounting platforms that utilize commutator brush holders that are integrally molded with the mounting base. Furthermore, the current carrying parts of the brush holders may be retained to the mounting base through the use of screws or the like. The mounting base and motor are then assembled on top of the fan cavity or, in some designs, inserted and secured with screws on a big center opening of the fan cavity.  
      Since the current carrying components are directly supported on the motor base, in order to comply with international safety requirements, the thermoplastic material used for the base must have a high temperature classification and self-extinguishing properties. Such materials are rather expensive and thus increase the cost of manufacturing a small appliance. This in turn drives up the cost of the final product.  
      Given the safety standards that must be met in order to obtain product certification on a worldwide basis, a motor mounting platform that allows a motor to be mounted in a small appliance while, at the same time, allowing all electrical carrying components to be displaced from the mounting platform, thereby eliminating the need for high cost thermoplastics would be an important improvement in the art.  
     SUMMARY OF THE INVENTION  
      The invention involves a motor mounting platform for use in an appliance, such as a vacuum cleaner. The motor mounting platform is constructed of a first material and at least two brush holders, which are constructed of a second material, are engaged to the motor mounting platform. At least one motor support and at lest two pair of brush holder guides are mounted to the motor mounting platform. Each pair of brush holder guides receivably engages the brush holders and are adapted to permit the brush holders to be removed from the motor mounting platform.  
      The invention also involves a motor mounting platform that is constructed of a first material and at least two brush holders, which are constructed of a second material, are engaged to the motor mounting platform. At least one motor support is integrally molded with the motor mounting platform. 
    
    
     BRIEF DESCRIPTIONS OF THE DRAWINGS  
       FIG. 1  is a top plan view of the motor mounting platform.  
       FIG. 2  is a sectional view taken along line  2 - 2  of the brush holder guides as seen in  FIG. 1 .  
       FIG. 3  is a sectional view taken along line  3 - 3  of the motor mounting platform as seen in  FIG. 1 .  
       FIG. 4  is a bottom plan view of the motor mounting platform.  
       FIG. 5  is a top plan view of the motor mounting platform showing a motor mounted on the platform.  
       FIG. 5A  is a sectional view taken along line  5 A, as seen in  FIG. 5 .  
       FIG. 6  is a sectional view taken along line  6 - 6 , as seen in  FIG. 5 .  
       FIG. 7  is an exploded perspective view showing a commutating brush, brush holder and a partial cut-away of the motor mounting platform showing the brush holder guides, guide slots and stop bar.  
       FIG. 8  is a partial cut-away side elevation of the assembled brush holder as seen in  FIG. 7 .  
       FIG. 9  is a partially assembled perspective view of the brush holder assembly as seen in  FIG. 7 .  
       FIG. 10  is a rear view of a fully assembled brush holder assembly as seen in  FIG. 7 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The invention involves a motor mounting platform  10  for use in a small appliance such as a vacuum cleaner. As shown in  FIGS. 1, 3 ,  5  and  6 , the motor mounting platform  10  is constructed of a first material and comprised of at least two brush holders  20 , constructed of a second material, removably engaged to the platform  10 . The second material is electrically non-conductive. In addition, the first material could have a lower thermal classification than the second material. For example, the first material, the material used to manufacture the mounting platform, may have a thermal classification as low as Underwriters Laboratories&#39; UL-94-HB.  
      The platform  10  includes at least one motor support  16  mounted to the platform  10 , at least two pair of brush holder guides  18  mounted directly to the platform  10  and at least two brush holders  20  constructed of electrically non-conductive material, removably engaged to the platform  10  within the brush holder guides  18 , whereby all electrical carrying components are displaced from the mounting platform  10 .  
      The motor mounting platform  10  has a first side  12  and a second side  21 . The second side  21  includes a cavity  22  surrounded by a wall  24 . The motor support  16  and the brush holder guides  18  are mounted on the first side  12 . Cavity  22  has an involute shape, as shown in  FIG. 4 .  
      The motor support  16  includes a first post  26  and a second post  28 . These first and second posts  26 ,  28  may be mounted opposite of each other around a hole  14  extending through the platform  10 .  
      When in use, as shown in  FIGS. 5 and 6 , a motor  30  is attached to the first and second posts  26 ,  28  in such a manner that the attachment points  32  of the motor  30  to the support posts  26 ,  28  are displaced from the surface  12  of the mounting platform  10 . This means, for example, that the motor  30  could be mounted on the tops of the first and second posts  26 ,  28 . Such an attachment allows the mounting platform  10  to be free of any direct electrical contact with any components carrying electrical current. Motor  30  is attached to the at least one motor support  16  in such a manner that the mounting platform  10  is free of any direct contact with any electrical carrying components.  
      The inventive motor mounting platform  10  may also include an exhaust outlet  34  that extends from the mounting platform  10 . This exhaust outlet  34  may be integrally molded with the mounting platform  10 .  
      The pairs of brush holder guides  18  are mounted on opposite sides of the hole  14  extending through the platform  10 . As shown in  FIG. 2 , the guides  18  may be comprised of a pair of inverted L-shaped guides, with each guide  18  opposing the other so as to form a slot  36  between them. A stop bar  38 , as shown in  FIG. 7 , capable of engaging a brush holder  20  is also mounted on the platform  10  between each guide slot  36  and the hole  14 .  
      The brush holders  20 , as shown in  FIGS. 7-10 , are comprised of a housing  40  having an opening  42  running lengthwise between a first end  44  and a second end  46 , a top side  48  including a first slot  50  in communication with the opening  42  and a second slot  52  in communication with the opening  42  and perpendicular to the first slot  50 , a bottom side  54  opposite the top side  48  and a first side  56  and a second side  58  opposite of each other and perpendicular to both the first and second ends  44 ,  46  and the top and bottom sides  48 ,  54 .  
      Although the housing  40  may have any one of several geometric shapes, in a typical brush holder  20  the housing  40  is rectangular in that the first side  56  and the second side  58  of the housing  40  are of a first length, the first end  44  and the second end  46  are of a second length and the first length is longer than the second length. Such a housing  40  may also have a top side  48  having a first width and a bottom side  54  having a second width with the second width being greater than the first width. The first and second sides  56 ,  58  of the brush holder  20  also include a bottom edge  60  adapted to be positioned within the inverted L-shaped guides  18 . The bottom side  54  also includes a notch  62  capable of engaging the stop bar  38 .  
      The brush holder housing  40  encloses a commutating brush  64  which is positioned within the opening  42  in the housing  40 . One end  66  of the commutating brush  64  extends from the first end  44  of the housing  40  while a wire  68  extends from the second end  70  of the brush  64  to a lead or terminal  72  positioned adjacent to the second end  46  of the brush holder  20 . A spring  74  encircling the wire  68  is positioned between the second end  70  of the commutating brush  64  and the second end  46  of the housing  40 . This spring  74  allows the brush  64 , which may be made of any suitable material including, for example, carbon, to remain in contact with the commutator  76  of the motor  30  throughout the life of the brush  64  (i.e., as the brush  64  wears down).  
      When in operation, the brush holder  20  is slid along the first side  12  of the motor mounting platform  10  in the slot  36  between the guides  18 . The bottom edge  60  of the first and second sides  56 ,  58  of the housing  40  mate with the upper portion of the guides  18  in order to prevent the brush holder  20  from being lifted up out of the slot  36 . The stop bar  38  momentarily interrupts the forward motion of the brush holder  20  sliding in the slot  36 . This interruption is overcome, however, by applying extra pressure to the brush holder  20  thereby causing the holder  20  to pass over the stop bar  36  until the bar  36  engages the notch  62  on the bottom side  54  of the housing  40 . This engagement prevents the brush holder  20  from backing out of the slot  36 .  
      Once the brush holder  20  is in position, the commutating brush  64  located in the brush holder  20  is in contact with the commutator  76  of the motor  30  which is mounted on the motor support  16  that is connected to the mounting platform  10 . As the commutator  76  rotates, an electrical current is transmitted through the commutating brushes  64  and the wire  68  extending from the second end  70  of the brush  64  to the lead  72  located in the brush housing  40 . This electric current is then transmitted through wires  80  connected to the lead  72 .  
      Because the commutating brush  64 , wire  68  and lead  72  are all enclosed in the brush housing  40 , no component carrying electrical current is in direct contact with the motor mounting platform  10 . This arrangement allows the mounting platform  10  to be constructed of less expensive material having a lower thermal classification.  
      The motor support  16  allows the attachment point(s)  32  of the motor  30  to be displaced from the mounting platform  10 . This too allows for the motor  30  to be mounted to the motor mounting platform  10  without having any electrical current carrying components in contact with the mounting platform  10 .  
      The motor support  16  and the guides  18  may be integrally molded with the mounting platform  10 . Furthermore, the motor support  16  may be in contact with the guides  18 .  
      Wire guides  81  may be connected to the platform  10 . These guides hold and retain in position the insulated electrical wires  80  running from the motor  30 .  
      Because no components carrying electrical current are in direct contact with the motor mounting platform  10 , the platform  10  may be made of a less expensive thermoplastic material without the need for special thermal classification. This results in great cost savings when compared to conventional motor mounting platforms that are known to be made of various materials including known thermoplastic materials that have a high temperature classification and self extinguishing properties.  
      The invention also involves a combination of a motor  30  mounted to a motor mounting platform  10  such that all electrical carrying components are displaced from the mounting platform  10 . As discussed above, and shown in  FIG. 5 , the motor  30  has an opening with a shaft  82  extending therethrough and the motor mounting platform  10  is comprised of a platform  10  with a hole  14  extending therethrough, at least one motor support  16  mounted to the platform  10 , at least two pair of brush holder guides  18  mounted directly to the platform  10 , at least two brush holders  20  made of electrically non-conductive material, the at least two brush holders  20  removably engaged to the platform  10  within the brush holder guides  18 .  
      The brush holders  20  are comprised of a commutating brush  64  positioned within an opening  42  in the brush holder  20 , the commutating brush  64  having a first end  66  and a second end  70  with the first end  66  being capable of contacting a commutator  76  of a motor  30 , a wire  68  located within the opening  42 , the wire  68  attached to the second end  70  of the commutating brush  64 , a spring  74  contacting the second end  70  of the commutating brush  64  and positioned between the second end  70  of brush  64  and the second end  46  of brush holder  20 . The spring  74  encircling the wire  68 . Wire  68  connects to terminal  72  located adjacent to the second end  46  of the brush holder  20  opposite the commutating brush  64 .  
      In an embodiment of the invention, the commutating brush  64  is made of carbon.  
      The invention also involves an inventive method for manufacturing a commutator brush assembly  86  having a commutating brush  64  within a commutator brush holder  20 . The method is comprised of the steps of: (a) providing a commutator brush holder  20  having an opening  42  between a first end  44  and a second end  46  in which the opening  42  receives a commutator brush  64  and a top side  48  having a first slot  50  therealong in communication with the opening  42 ; and (b) positioning a lead wire  68  for connecting to the commutator brush  64  through the first slot  50 .  
      The method further comprises the steps of: (1) connecting a first end  90  of a lead wire  68  to a terminal lead  72 ; (2) encircling the lead wire  68  with a spring  74 ; (3) securing a second end  92  of the lead wire  68  to an end of the commutating brush  64 ; (4) placing the commutating brush  64  within the opening  42  at the first end  64  of the commutator brush holder  20  such that the lead wire  68  is aligned within the first slot  50 ; (5) sliding the lead wire  68  along the length of the first slot  50 ; and (6) securing the terminal lead  72  to the brush holder  20 . In addition, a second slot  52  is provided in the top side  48 , the second slot  52  being in communication with the opening  42  and perpendicular to the first slot  50  and the terminal lead  72  is secured within the second slot  52 .  
      The inventive steps of the method could further comprise the step of sliding the lead wire  68  along the length of the first slot  50  until reaching the second slot  52 , where the second slot  52  is adjacent to the second end  46  of the brush holder  20 .  
      While the principles of the invention have been shown and described in connection with various embodiments, it is understood clearly that such embodiments are by way of example and are not limiting.