Clothes dryer drive and blower system

An automatic clothes dryer having separately driven drum and blower.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to automatic clothes dryers having separately driven drum and blower

2. Description of the Related Art

Automatic clothes dryers are well known, and typically comprise, a cabinet enclosing a horizontally rotating drum for holding items to be dried and accessible through an access door at the front of the cabinet. The drum is rotated by a belt which is driven by a motor. The motor also drives a blower assembly which delivers dry, heated or unheated air to the drum for drying the items, and exhausts humid air from the drum to a discharge location exterior of the cabinet. The motor and blower assembly are typically mounted in a lower portion of the cabinet beneath the drum. The drum has a first diameter which is ideally maximized within the dimensions of the dryer cabinet. The blower assembly typically utilizes a horizontally rotating fan, having a second, smaller diameter, which must fit within the remaining dryer cabinet space not occupied by the drum. This frequently limits either the size of the drum or the size of the fan, or both.

Dryer cabinets are typically dimensioned to occupy a predetermined sized space, height, width, and depth, in a laundry room or basement area. This simplifies the construction of laundry rooms and any cabinetry. However, a preselected dimension necessarily limits the cabinet interior space available for enclosing the drum, the motor, and the blower assembly. This is a disadvantage in that there is a growing demand for larger capacity dryers.

The capacity of a conventional dryer is further limited in that conventional dryers use a single-shaft, dual-drive motor for driving both the drum and the blower. One end of the shaft is provided with a pulley for driving the belt rotating the drum. The other end of the shaft is directly coupled to the shaft of the blower impeller. The combined mounting of the drum drive and the blower limits where the motor can be mounted within the cabinet as the drum drive needs to be located such that the belt can connect to the drum, with the result that the motor is often located in such a position that the diameter of the drum cannot be maximized within the cabinet in order to accommodate the motor, drum drive, and blower housing.

The coupling of the blower impeller directly to the motor shaft while mechanically convenient is disadvantageous in that it requires the air flow path through the dryer to have additional paths or bends, which slow down the air flow and increase the back pressure in the system. Specifically, the longitudinal axis of the blower is oriented either coaxially or in parallel with the longitudinal axis of the motor. This configuration requires a relatively large space for the blower and motor. This also typically results in a blower exhaust opening which is oriented 90° to the dryer exhaust vent, thereby requiring a 90° elbow between the blower exhaust opening and the dryer exhaust vent.

There is an increasing need in the household dryer market for a dryer with a larger drum capacity for drying larger loads, thereby minimizing the number of separate loads that must be dried, and drying heavy, bulky items such as comforters, rugs, and the like. This need continues to increase as washers are able to achieve larger capacities. Conventional dryer configurations have reached their capacity limits. A new dryer configuration is needed.

SUMMARY OF THE INVENTION

In one embodiment, an automatic clothes dryer comprises a cabinet defining an interior space and having an opposing top and bottom and opposing sides extending between the top and bottom to partially define the interior space and to form corners at the junction of the top and bottom with the sides, a cylindrical drum defining a drying chamber and rotatably mounted within the interior space to define subspaces within the interior space between the corners and the drum, a drive motor mounted within one of the subspaces and having an output shaft operably coupled to the drum for rotating the drum, and a blower mounted within the interior space out of the subspaces and between the drum and one of the bottom and top, and fluidly coupled to the drying chamber for moving air through the drying chamber, the blower having a drive shaft separate and remote from the output shaft to permit the independent positioning of the blower and drive motor.

In another embodiment, an automatic clothes dryer comprises a cabinet defining an interior space. A drum is rotatably mounted within the interior space and defines a drying chamber. A drive motor is mounted within the interior space and has an output shaft operably coupled to the drum for rotating the drum. A blower is mounted within the interior space and is fluidly coupled to the drying chamber for moving air through the drying chamber. The blower has a drive shaft rotatable about a blower axis that is separate and orthogonal to the drum axis, and the direction of air flow exhausted from the blower is substantially parallel to the drum axis.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

Referring to the Figures, and in particular toFIGS. 1 and 2, an embodiment of an automatic clothes dryer10according to the invention is illustrated comprising a cabinet12having a control panel14for controlling the operation of the dryer10, a door16hingedly attached to a front wall20, and a chassis22, which supports a top wall18, the front wall20, and a rear wall24. The clothes dryer10described herein shares many features of a well-known clothes dryer, and which will not be described in detail except as necessary for a complete understanding of the invention. In particular, the automatic clothes dryer industry has developed a standardized size for an automatic clothes dryer which enables a residential laundry space to be dimensioned to accommodate a standard sized automatic clothes dryer, thereby eliminating the time and expense of customizing the laundry space to accommodate a selected dryer. The embodiment of the automatic clothes dryer10described herein preferably comprises a cabinet12having standardized dimensions. The standard dimensions may be either a standard height or a standard width. Preferably, the standard height is no more than 38 inches and the standard width is no more than 29 inches.

Referring toFIGS. 2-5, the cabinet12encloses a rotating drum30, a centrifugal blower assembly120, and a motor assembly122. The drum30is rotatably supported between a front drum panel50and a rear drum panel52. The front drum panel50is located intermediate the drum30and the front wall20, and is preferably fabricated of stamped sheet metal. The rear drum panel52is located intermediate the drum30and the rear wall24, and is preferably fabricated of stamped sheet metal.

The front drum panel50is a somewhat irregularly-shaped panel comprising an inner face60and an opposed outer face62. The front drum panel50is provided therethrough with a somewhat conduit-like access wall64terminating at a first end in a D-shaped access lip66defining a D-shaped access opening68, and at a second end in a raised, circular drum flange70extending away from the inner face60. The access lip66is adapted in a well-known manner for sealable closure of the door16over the access opening68. The drum flange70is adapted in a well-known manner for cooperative registry with the drum30and is rotatable mounted on drum rollers82.

Extending along a bottom portion of the access wall64adjacent the access opening68is an air circulation enclosure72having a grille74therethrough. An upper portion of the enclosure72is provided with a suitable slot (not shown) for receipt of a well-known removable lint screen76(FIG. 3). The air circulation enclosure72transitions to an air circulation duct78extending away from the front drum panel50to terminate in an exhaust opening80. The air circulation duct78comprises a well-known hollow duct work fluidly connected with the air circulation enclosure72to direct the flow of air through the grille74and into the air circulation enclosure72, to exit through the exhaust opening80. The air circulation duct78can comprise separate front and rear pieces which are assembled to the front drum panel50, or can be integrally formed with the front drum panel50.

The drum30comprises a generally hollow, cylindrical drum body36, having a diameter, terminating at one end in a circular front sealing flange32and at a second, opposed end in a circular rear sealing flange34, and defining a drying chamber40. The drum body36is provided with a plurality of irregularly-spaced, radially-inwardly directed paddles (also known as “baffles”)38extending into the drying chamber40for agitation of items placed in the dryer10for drying as the drum30is rotated.

The drum30is supported within an upper portion of the cabinet12to rotate about a horizontal axis. Beneath the drum30, the cabinet12defines an interior space comprising a left subspace54and a right subspace56when viewed from the front of the dryer10(FIG. 4).

Referring toFIGS. 3 and 8, the front sealing flange32is adapted for slidable registry with the drum flange70, preferably by insertion of the front sealing flange32coaxially into the drum flange70. A well-known ring-like gasket (not shown) can be retained between the front sealing flange32and the drum flange70to improved air tightness, reduce vibration and noise, and facilitate slidable rotation of the front sealing flange32in the drum flange70.

Referring now toFIGS. 2 and 8, the rear drum panel52is a somewhat irregularly-shaped panel comprising an inner face90and an opposed outer face92. A raised, circular drum flange94extends away from the inner face90and circumscribes an end panel96having a grille98extending therethrough at an upper portion thereof. The drum flange94is adapted for slidable registry with the rear sealing flange34of the drum30, preferably by insertion of the rear sealing flange34coaxially into the drum flange94. A well-known ring-like gasket (not shown) can be retained between the rear sealing flange34and the drum flange94to improve air tightness, reduce vibration and noise, and facilitate slidable rotation of the rear sealing flange34in the drum flange94. As illustrated inFIG. 3, the front drum panel50and the rear drum panel52are positioned relative to each other so that the centers of the drum flanges70,94are in horizontal coaxial alignment for rotation of the drum30about a horizontal axis.

An air inlet port100is provided in the rear drum panel52at a lower portion thereof adjacent the drum flange94. A vertical air conduit116extends along the outer face92for fluid communication of the air inlet port100with the grille98to direct the flow of air through the inlet port100to exit the grille98.

As illustrated inFIGS. 2,3and8, the drum30is supported in an upper portion of the cabinet12above the interior space26comprising the left subspace54and the right subspace56. The interior space is adapted for receipt of a centrifugal blower assembly120, a motor assembly122, and an inlet air conduit114, which are fixedly attached in a well-known manner to the chassis22. The inlet air conduit114comprises an elongated, hollow body mounted in the left subspace54, and terminating at a first end in an air inlet180and at an opposed second end in an air outlet182. The inlet air conduit114can be provided with a well-known heating element115for heating air prior to introduction of the air into the drying chamber40. As illustrated also inFIG. 11, the inlet air conduit114is fluidly connected to the air inlet port100to supply air through the vertical air conduit116and the grille98into the drying chamber40.

The motor assembly122comprises a well-known electric motor128mounted in a suitable bracket for fixedly attaching the motor assembly122to the chassis22. The motor128is adapted in a well-known manner with an output shaft for driving a drum drive belt124at a first end, and for driving a blower drive belt126at a second end. The drum drive belt124encircles the drum30for rotation of the drum30with rotation of the motor128. The blower drive belt126is operably connected to the blower assembly120for operation of the blower assembly120with rotation of the motor128.

Referring now toFIGS. 6,7, and10, the centrifugal blower assembly120comprises a generally well-known rotating impeller enclosed in a housing which is configured to draw in air coaxially and exhaust the air tangentially in a direction orthogonal to the direction of air flow into the impeller. The blower assembly120comprises an upper blower housing130in air-tight registry with a lower blower housing132. The upper housing130comprises a somewhat helical-shaped shell having a helical wall162with a centrally located shaft aperture166therethrough. Depending orthogonally from the helical wall162along the perimeter thereof is a perimeter wall164. The helical wall162and the perimeter wall164transition tangentially into a blower outlet136.

The lower blower housing132comprises an irregularly-shaped shell having a somewhat helical-shaped plate portion154adapted for coextensive registry with the upper blower housing130. Depending orthogonally from the plate portion154is an arcuate wall156transitioning to a housing floor158. The arcuate wall156and the housing floor158extend away from the plate portion154to terminate in a rectilinear edge160.

A guard plate134comprising a helical plate144is located between the upper blower housing130and the lower blower housing132. A rectilinear flange146extends away from the helical plate144, and is adapted for cooperative registry with the arcuate wall156and the rectilinear edge160to define a rectilinear blower inlet172. The center of the helical plate144comprises a depending bowl148terminating in a coaxial rim150defining a coaxial impeller inlet152extending therethrough.

The impeller138comprises a circular wall portion140supporting along a first side a regularly-spaced array of arcuate fins142. The wall portion140can comprise along an opposed second side an annular bearing tube174having a coaxial shaft aperture176and adapted for fixed registry with a drive shaft168. The center of the wall portion140can also be fabricated with a conical surface extending away from the first side to direct air flowing coaxially into the conical surface radially outwardly along the fins142.

The blower assembly120is assembled with the impeller138received in the upper blower housing130and the drive shaft168extending through the shaft aperture166of the upper blower housing130into the shaft aperture176of the bearing tube174. The intermediate plate134is inserted between the upper blower housing130and the lower blower housing132to define a first, upper chamber enclosing the impeller138, and a second, lower chamber defined by the arcuate wall156and the housing floor158. Rotation of the impeller138will draw air through the blower inlet172into the lower chamber, axially through the impeller inlet152into the upper chamber, radially outwardly by the movement of the fins142, and tangentially out the blower outlet136.

The drive shaft168is provided with a pulley170around which the blower drive quarter-turn stretch belt126is looped for rotation of the impeller138with operation of the motor128. As illustrated inFIG. 9, the use of a quarter-turn stretch drive belt126enables the impeller138having a vertical drive shaft168to be operated by the motor128having a horizontal output shaft.

The separating of the blower assembly120from the motor output shaft enables the blower assembly120to be placed remotely from the motor122. The drive shaft168can be oriented at an angle relative to the motor output shaft, and the angle can be 90 degrees. The axis of rotation of the drum30can be orthogonal to the drive shaft168, or parallel to the motor output shaft.

Preferably, the blower assembly120is mounted to the chassis22beneath the drum30. The motor assembly122is preferably mounted to the chassis22in the right subspace56, laterally of the blower assembly120. In this position, the blower assembly does not interfere with the sizing of the drum. In prior configurations, the blower would have been mounted to the motor, and the radial extent of the blower alone or in combination with the surrounding housing would have been great enough to prevent the maximizing of the drum.

Advantageously, the blower assembly120is oriented so that the blower outlet136extends toward the rear of the dryer10. An exhaust air conduit112is fixedly attached to the blower outlet136to exit the air through an exhaust outlet, or air exhaust port110for registry with an external dryer vent hose. The direction of air flow from the blower outlet136to the exhaust outlet is constant. Further, the longitudinal axis along the exhaust air conduit112varies less than 90 degrees. That is, air flows unidirectionally, e.g. no sharp bends, from the blower outlet136through the exhaust air conduit112to the air exhaust port110, thereby minimizing losses due to bends in the exhaust air conduit112downstream of the blower assembly120.

As illustrated inFIG. 8, during operation of the dryer, fresh air is drawn into the inlet air conduit114, represented by the air flow vector identified as “A.” The air can selectively be heated in the inlet air conduit114, and is then drawn into the vertical air conduit116, represented by the air flow vector identified as “B.” The air travels up the vertical air conduit116to enter the drum30through the grille98, represented by the air flow vector identified as “C.” The air is then drawn through the grille74into the air circulation duct78, represented by the air flow vector identified as “D,” and out the exhaust opening80into the blower inlet172, represented by the air flow vector identified as “E.”

Referring toFIG. 7, air represented by the air flow vector “G” travels into the lower blower housing132and upwardly through the impeller inlet152in the intermediate plate134, represented by the air flow vector “H.” Rotation of the impeller138, illustrated inFIG. 7as counterclockwise, draws air radially outwardly to the perimeter of the impeller138, represented by the air flow vector “I,” and along the perimeter of the upper blower housing130to exit the blower outlet136, represented by the air flow vector “J.” Referring again toFIG. 8, air exhausted through the blower outlet136enters the exhaust air conduit112and is exhausted through the air exhaust port110, represented by the air flow vector identified as “F.”

The use of a centrifugal blower oriented to rotate about a vertical axis enables the blower to be mounted in the automatic clothes dryer below the drum30. The centrifugal blower has a much smaller vertical profile than the prior art blowers alone and in combination with the surrounding air duct housing. As a consequence of not directly mounting the blower to the motor output shaft, the blower assembly can be located remotely of the motor resulting in more space is available for the drum, thereby enabling the size of the drum to be maximized for a given cabinet configuration.

The ability to locate the blower separately from the motor also enables the blower to be mounted in a horizontal orientation for rotation about a vertical axis, instead of a vertical orientation for rotation about a horizontal axis. The change in orientation further aids in the blower assembly being positioned such that the drum diameter can be maximized.

Furthermore, the motor can be remotely located relative to the blower, providing further flexibility in minimizing the space occupied by the blower and motor, and maximizing the space available for the drum. The separation and repositioning of the blower relative to the motor also enables the use of a larger diameter blower, thereby increasing air flow through the drum to accommodate any increased drum size and increased dryer load.

The repositioned blower is further advantageous in that is also be oriented so that the exhaust opening from the blower can be connected in-line with the exhaust opening through the dryer cabinet, thereby eliminating a 90° bend typically required with a conventional, vertically oriented blower. The elimination of one bend greatly reduces the backpressure in the air flow system and improves the air flow rate for a given blower. In fact, it is possible to reduce the blower capacity from a traditional blower, resulting in a cost improvement.

It should be noted that while the blower as illustrated is shown as being driven by a belt connected to the drum motor, the blower could be a self-powered blower having its own motor. Additionally, the blower rotational speed can be selected as desired (either by selection of pulley ratios or by selection of its own blower motor) and is not limited to operating at the same speed as the drum drive motor shaft as is the case where a blower is directly coupled to the drum drive motor shaft.