Patent Publication Number: US-2013239428-A1

Title: Method to reverse cylinder drive in a direct belt on basket dryer/tumbler

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to laundry dryers, and more particularly, to laundry dryers in which the laundry containing tumbler basket is driven by a reversible motor in alternative rotary directions. 
     BACKGROUND OF THE INVENTION 
     Laundry dryers commonly have a laundry containing tumbler basket driven by a drive belt which surrounds a rear portion of the basket. Since there is no pulley about the basket, only belt tension and idler and drive pulleys maintain proper direction of the belt. While it is desirable to drive the basket in opposite rotary directions to prevent tangling of large items, such as sheets, linens, and the like contained in the basket during drying, reversing the direction of drive can cause the belt to come off centered, resulting in edge wear and shortening of belt life, or complete dislodgement of the belt from the drive or idler pulleys. Moreover, sequential reversing of the rotary direction of the drive motor can create fatigue, cracking, or tearing of the sheet metal panel of the dryer cabinet upon which the drive motor is mounted by virtue of shock forces and vibrations occurring during reversible operation. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a laundry dryer with a belt driven tumbler basket that is adapted for more reliable reversible operation. 
     Another object is to provide a laundry dryer as characterized above in which the drive belt is maintained in stable centered position on the drive and idler pulleys for more reliable operation. 
     A further object is to provide a laundry dryer of the above kind in which the drive motor has a mounting that resists fatigue cracking and tearing of the cabinet wall upon which the motor is mounted during reversible driving movement of the tumbler basket. 
     Still another object is to provide a laundry dryer of the foregoing type with a drive motor mounting arrangement that is relatively simple in design and lends itself to easy manufacture. 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective of an illustrative laundry dryer in accordance with the invention; 
         FIG. 2  is an enlarge perspective of the laundry dryer shown in  FIG. 1  with portions of the cabinet removed in order to depict internal components of the dryer; 
         FIG. 3  is a diagrammatic depiction of the tumbler basket of the illustrated laundry dryer; 
         FIG. 4  is an exploded perspective of a tumbler basket drive motor and its mounting arrangement in the illustrated dryer; 
         FIG. 5  is an enlarged perspective of the drive motor supported within its mounting; 
         FIG. 6  is an enlarged fragmentary perspective showing a biasing mechanism for the drive motor mounting; 
         FIG. 7  is a further perspective of the illustrated drive motor mounting showing drive and idler pulleys in relation to the tumbler basket drive belt; 
         FIG. 8  is a perspective of a stabilizing member of the illustrated drive motor mounting arrangement; and 
         FIG. 9  is a side elevational view of the stabilizing member shown in  FIG. 8 . 
     
    
    
     While the invention is susceptible of various modifications and alternative constructions, a certain illustrative embodiment thereof has been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now more particularly to the drawings, there is shown an illustrative laundry dryer  10  in accordance with the invention. The illustrated dryer  10  includes an outer cabinet  11  comprising a plurality of relatively thin sheet metal panels, including a front panel  12 , top panel  13 , side panels  14 , a rear panel  15 , and a center panel  16  between the front and rear panels  12 , 15 . A front opening tumbler basket  18  is rotatably disposed within the cabinet  11  by a rearwardly extending axial  19  and a pair of rollers  20  supported within the cabinet  11  below a front end of the tumbler basket  18 . 
     A conventional front opening door  21  is mounted in the front panel  12  for enabling access to the tumbler basket  18 . The tumbler basket  18  in this case has a perforated rear axial end through which heated air is introduced into the tumbler basket  18  in a conventional manner, a rearward unperforated cylindrical portion  22  disposed in sealed relation between the rear panel  15  and the center partition  16 , and a forward perforated cylindrical portion  24  disposed between the center partition  16  and the front panel  12 . 
     For heating items within the tumbler basket  18  during a drying operation, a heater  25 , which may be electric or gas powered, is mounted on a rear panel  15  of the dryer and a fan  26  is mounted below the heater  25 . As is known in the art, hot air is drawn from the heater  25  through an air inlet  28  communicating with the perforated rear axial end of the tumbler basket  18 , through the basket  18  and an air outlet  29  communicating with the forward perforated basket portion  22 , through a lint filter  30 , and then from the fan  20  to the outside environment. A protective guard  31  in this case is mounted on a side of the heater  25 . 
     For rotatably driving the tumbler basket  18  during a drying operation, a drive motor  35  is mounted on a rear side of the cabinet panel  15  below the heater  25 . The drive motor  35  has a drive shaft  36 , which carries a drive pulley  38  disposed within the cabinet  11  for driving an endless belt  40  trained about the drive pulley  38  and the rear unperforated end  22  of the tumbler basket  18 . The drive belt  40  preferably is of a poly-V construction having a driving side formed with a plurality of laterally spaced V-grooves for enhanced frictional engagement with corresponding grooves in the drive pulley  38 . A pair of idler pulleys  41 , 42  each rotatably supported on a respective support shaft  44 , 45  ( FIG. 4 ) are provided for guiding the belt  40  into tight frictional engagement about the outer periphery of the tumbler basket  18 . The rear cabinet panel  16  in this case has a cutout opening  47  through which the motor shaft  36  extends and for permitting access to the drive pulley  38 . A cover plate  49  is removably attached to the rear panel  16  closing an upper portion of the cutout opening during operation of the motor for minimizing air flow through the opening. 
     For facilitating drying of large items, such as sheets, lines, coats, and the like without tangling during rotation of the tumbler basket  18 , the drive motor  35  is operable for sequentially reversing the direction of rotary movement of the tumbler basket  18 . The drive motor  18  preferably is an 8-pole motor and is operable without slippage of the drive belt  40  on the drive pulley  38  for sequentially rotating the tumbler basket  11  up to 300 rpm every 30 seconds in opposite rotary direction. Heretofore, as indicated above, such sequential reversing of the drive motor can cause cracking or tearing of the rear panel of the cabinet upon which the drive motor is mounted, which typically is a thin sheet metal panel with a wall thickness of about only 0.033 inches in thickness. Reversing direction of the drive heretofore also can cause the drive belt  40  to become off-centered on drive and idler pulleys  38 , 41 , 42  resulting in edge wear and shortening of belt life, if not complete dislodgement of the belt from the pulleys. 
     In accordance with the invention, an improved mounting is provided for the drive motor and drive belt idler pulleys that prevents damage to the panel of the cabinet upon which the drive motor is mounted during rapid sequential reversal of direction of rotation of the tumbler basket and maintains the drive belt in substantially centered relation to the idler and drive pulleys. In the illustrated embodiment, the motor mounting includes a right angle bracket  45  comprising a first gusset plate  46  affixed to a rear side of the rear cabinet panel  15  transverse to the axis of the drive motor shaft  36  and a second integral right angle gusset plate  48  extending rearwardly from one side of the first gusset plate  46  parallel to the axis of the motor shaft  36 . The drive motor  35  has a mounting bracket  50  affixed on a side that is bolted to a pivot plate  51  supported for pivotal movement on a support shaft  52  extending adjacent an upper side of the gusset plate  46  ( FIG. 4 ). To facilitate pivotal movement of the pivot plate  51 , bushings  54  are interposed between the support shaft  52  and mounting apertures of the pivot plate  51 . A top cover plate  55 , also having a tapered or gusseted configuration, is bolted to the top of the right-angled bracket  46  in overlying relation to the support rod  52 . 
     For biasing the pivot plate  51  and the motor  35  mounted thereon such that the motor shaft  36  and drive pulley  38  are urged in a generally downward belt tightening direction, an elongated carriage bolt  58  and spiral spring  59  are provided. With a head of the carriage bolt  58  retained on an outer side of the gusset plate  46 , the carriage bolt  58  extends through an aperture in the gusset and pivot plates  46 , 51 , with the spiral spring  59  being biased between the pivot plate  51  and a nut  60  affixed to a terminal end of the carriage bolt  58 . A biasing force of the spring  59  urges the pivot plate  51  in a downward direction toward the gusset plate  46 , urging the drive motor  35  and drive pulley  38  in a downward direction for maintaining tension on the drive belt  40  during operation. 
     In carrying out the invention, the motor support shaft  52  and the idler pulley shafts  44  each is affixed to and supported by a stabilizing member  65 , which is affixed to the rear cabinet panel  16  and dimensioned so as to be stronger and more robust than the relatively thin walled rear cabinet panel  16  for stabilizing the axes of the idler pulleys  41 , 42  and motor drive pulley  38  for more reliable operation. The illustrated stabilizing member  65  has an elongated configuration and is mounted on an inner side of the rear cabinet panel  16 . The stabilizing member  65  has a threaded aperture  66  at one end for fixedly receiving and supporting a threaded end of the motor support rod  52  that extends through an aperture in the rear panel  16 . A nut  68  carried by the support rod  52  is tightened against an outer side of the rear cabinet panel  16  for securely affixing the end of the stabilizing member  65  to the cabinet panel  16  ( FIG. 4 ). A threaded fastener  68  engageable with a threaded aperture  69  of the stabilizing member  65  affixes the opposite end of the stabilizing member  65  to the cabinet panel  16 . The shaft  45  of one idler pulley  42  in this case is threadably affixed to a threaded aperture  45   a  adjacent an end of the stabilizing member  65  opposite the end to which the motor support shaft  52  is affixed, and the shaft  44  of the other idler pulley  41  is threadedly supported in an aperture  45   b  in an upstanding integral hub  70  of the stabilizing member  65  in slightly elevated relation to the motor support rod  52  and the idler shaft  45 . A tubular spacer  74  in this instance is interposed between each idler pulleys  42 , 44  and the stabilizing member  65 . A downwardly opening cutout  71  is formed centrally within an underside of the stabilizing member  65  for providing clearance to the motor drive shaft  36  and pulley  38 . 
     The illustrated stabilizing member  65 , which may be made of cold rolled steel, has a transverse thickness “t” substantially greater than the thickness of the rear cabinet panel  16 . Preferably, the stabilizing member has a thickness “t” of between 15 and 25 times the thickness of the rear cabinet panel  16 , and most preferably at least 20 times the thickness of the rear cabinet panel  16 . In the illustrated embodiment, the cabinet panel  16  has a thickness of 0.033 inches and the stabilizing member has a thickness of ⅝″. The stabilizing member  65  preferably has an elongated configuration with a long dimension of at least 8″. 
     While the theory of operation is not entirely understood, it is believed that the robust stabilizing member  65  maintains the axes of the drive and idler pulleys  38 , 41 , 42  in sufficiently parallel relation to each other sufficient to keep the drive belt  40  from straying away from the pulleys when operation of the drive motor is reversed. The stabilizing member  65  also solves the problem of attaching the reversing motor to the relatively thin sheet metal panel  16  of the dryer cabinet that is otherwise subject to fatigue and cracking caused by the shock forces and vibrations associated with reversal in the drive motor. The substantial thickness of the stabilizing member  65  is believed to spread the loads and absorb the shock forces and vibrations occurring by rapid stopping and starting of the motor in opposite direction. 
     From the foregoing, it can be seen that a laundry dryer is provided with a belt driven tumbler that is adapted for more reliable reversible operation. The drive belt is maintained in a stable centered position on the drive and idler pulleys during reversible operation, and the robust nature of the stabilizing member to which the motor support rod and idler pulleys are mounted or prevents fatigue cracking and tearing of the relatively thin rear cabinet panel upon which the motor is mounted.