Dryer drum vane

A dryer has complex angled surfaces and a plurality of grip elements thereon. The angled surfaces have varying angles of inclination relative to a base of the dryer vane and the characteristics of the grip elements vary in relation to the angle of inclination of the surface portions upon which they are disposed. The grip elements may protrude from the vane surfaces and the height of the grip elements may vary in relation to the varying angle of inclination of the surfaces. Taller grip elements may be provided on the less inclined surfaces and shorter grip elements may be provided on the more inclined surfaces.

TECHNICAL FIELD

This invention relates generally to laundry dryers, and more particularly to elements mounted within a rotatable drum of the dryer for enhancing tumbling action of the laundry load within the dryer.

BACKGROUND

Automatic laundry dryers generally employ a horizontally oriented, front load rotatable dryer drum for tumbling laundry during a drying process in which air, typically heated air, is introduced into the drum. The tumbling allows for the laundry to be sufficiently exposed to the air flow and also reduces wrinkling. Conventional dryer drums contain baffles or vanes on the interior of the drum which aid in tumbling the laundry. During rotation of the dryer drum, the vanes contact the laundry and lift it to help ensure that the laundry is tumbled. Most dryer drums have vanes with straight linear configurations oriented in alignment with the rotation axis of the drum. Dryer drums, having vanes which direct clothes in the axial direction of the dryer drum have also been proposed, such as for improving air flow or to facilitate unloading. See, e.g., U.S. Pat. No. 6,698,107 to Song et al. and U.S. Pat. No. 3,364,588 to Ziegler. Such vanes generally are disposed at an angle skewed relative to the rotational axis of the dryer drum, so that the skewed face of the vane can direct the clothes axially. Mounting the vanes in a skewed manner may be more difficult than mounting the vanes in alignment with the rotation axis. Further, if the drum is installed in the dryer backwards, then the vanes would direct clothes in a direction opposite of the intended direction. Additionally, having a skewed vane configuration differing substantially in appearance from the vanes present in a matching front load washer may be less preferable to a consumer than if the vanes are similarly configured and oriented. Therefore, it would be advantageous to provide a dryer vane that can move the clothes axially without requiring a skewed mount of the vane while still ensuring that the laundry is tumbled efficiently.

SUMMARY

The present disclosure is directed to dryer drum vanes that may be mounted to extend in alignment with axial direction of the drum and yet effectively move the laundry in an axial direction of the drum during tumbling. The vanes may be configured to ensure efficient lifting of the laundry during tumbling by providing differential grip enhancement along the surface of the vane varying in relation to the varying angle of inclination of the surface.

According to one aspect of this disclosure, a dryer vane has complex surfaces and a plurality of grip elements. The complex surface portions may have varying angles of inclination relative to a base of the dryer vane and the grip elements may vary according to the angle of inclination of the complex angled surfaces upon which the grip elements are disposed. For example, the grip elements may protrude from the complex surfaces and the height of the grip elements may vary with respect to the angle of inclination of the complex surface portions from which the grip elements protrude. Taller grip elements may be provided on the less inclined surfaces and shorter grip elements may be provided on the more inclined surfaces.

In a related aspect, one or more dryer vanes are positioned on the inside of a drum of a dryer having a housing, a rotatable drum within the housing, and an air flow system which directs an air flow through the drum. The vanes may be mounted in alignment with the rotation axis of the drum.

Another aspect of this disclosure is directed to a method of increasing the efficiency of an automatic dryer which may include a dryer housing and a rotatable drum with at least one dryer vane positioned inside the drum, by directing articles in an axial direction of the drum towards a moisture sensor therein. Each of the dryer vanes has complex surfaces which have varying angles of inclination relative to a base of the dryer vane. The grip of the complex surfaces on items in the load may be enhanced by a plurality of grip elements which protrude from the complex surfaces such that the heights of the grip elements vary with respect to the angle of inclination of the complex grip surface portions from which the grip elements protrude. The operation of the dryer may be controlled based, at least in part, on information provided from the moisture sensor.

These and additional features and advantages of the invention disclosed herein will be further understood from the following detailed description.

DETAILED DESCRIPTION

An illustrative front-load automatic laundry dryer1is shown inFIGS. 1 and 2. The dryer1includes a generally rectangular housing or cabinet3, an access door5and a user interface (control panel)7. The user interface7allows the user to control the operation of the dryer via such means as buttons, rotatable knobs, and lighted indicators, in a generally known fashion. It may also include a screen for displaying visual operation information to the user in a known manner. In the depicted embodiment, door5is circular and hinged to a front bulkhead and panel of the dryer to allow the user to open and close the door5, to insert laundry into a drum rotatably mounted within the housing.

In a generally conventional manner, an air flow system draws air through a heater section4and into the drum11through a duct provided on the backside of a rear bulkhead9to which a rear side of the drum may be rotatably mounted. Preferably, air is drawn from inside of the housing into heater4to take advantage of heat exchange with the drum11and the heater. The air may be exhausted from the drum11through an outlet duct incorporated into the front drum-supporting bulkhead, which is concealed behind the front panel visible inFIGS. 1 and 2. A single motor13may be used to drive both the rotation of the drum (in forward and reverse directions), and a blower2. Blower2is provided in fluid communication with the drum outlet duct, to create a vacuum causing air to flow through the system and be exhausted outside of the housing through a rearwardly extending exhaust tube6. The drum11is driven by motor13via a belt8.

Referring now toFIG. 3, the dryer drum11may contain a plurality of dryer vanes15which are spaced regularly around the inner surface of the drum11. In the embodiment shown inFIG. 3, three dryer vanes15(only 2 vanes are visible) are positioned approximately equilaterally (120 degrees apart) around the inner circumference of the dryer drum11, in alignment with the rotation axis of the drum. As shown inFIGS. 4A-4I, illustrative dryer vane15is an elongated structure which is generally triangular in cross sectional shape with complex oppositely directed surfaces21and23extending up from a generally rectangular base17to an apex19. Herein, “complex surface” refers to a surface extending in three dimensions and having a curvature that varies in one or more of those dimensions. As seen inFIG. 4B, dryer vane15has a generally linear bottom edge and an arc-shaped upper profile (varying height) extending from one lateral end to the other. As can be seen inFIG. 4A, the dryer vane15has a longitudinal axis and exhibits reverse symmetry about a centerline extending normal to the longitudinal axis, as well as about a longitudinal centerline of the vane.

The illustrated vane shape is just one of a virtually unlimited variety of shapes that could be used in carrying out aspects of the invention. As described herein below, an important aspect of the invention concerns varying the grip characteristics of the contact surfaces of the vane in relation to a varying angle of inclination of those surfaces.

For explanatory purposes, the surface of the vane15which contacts the laundry when the drum is rotated will be referred to as the leading surface, and the surface on the opposite side of the vane will be considered the trailing surface. These surfaces may be either of surfaces21and23, depending on the rotation direction of the drum. The end of the vane closest to the dryer door5(access port) may be considered the proximal end of the vane and the end of the vane farthest from the dryer door5may be considered the distal end of the vane.

As seen inFIGS. 4A-4I, the illustrative vane15has a gentle “twist” imparted to its generally triangular cross-sectional shape. In a general sense, it is as if an elongated vane of generally triangular cross-section was distorted by gripping the vane at its ends and imparting a slight relative rotation to the surfaces above the rectangular base, or by holding the ends of the vane stationary and imparting a slight twist to the surfaces about a center point of the vane. Of course, this is not typically how the vane would be formed. Rather, more typically, the vane would be formed in the desired final shape by injection molding in a correspondingly shaped mold form (die). The opposing surfaces21and23have inclinations that vary along their lengths in a complementary fashion. For example, the inclination(s) of surface21at vane end25is equal and opposite to the inclination(s) of the rear surface23at the opposite vane end27. In general, two points, one on the front surface21and one on the rear surface23, which are equidistantly spaced from the center in opposite axial directions, and at the same height, will have an equal inclination (in opposite directions). Rather than extending linearly, as seen inFIG. 4A, apex19of the vane has a generally S-shaped curve with a center corresponding to the center of the vane and its ends flaring outwardly.

Opposing surfaces21and23also have a curvature along their lengths presenting a lateral angle of incidence that vary with respect to the generally straight edge of the base. By varying the lateral angle of incidence, the “twisted” shape of the vane15can, in addition to tumbling the laundry, serve to convey it in one axial direction or the other (depending on the direction of rotation), without the need to mount the vane15with a skew relative to the drum rotation axis.

As mentioned, the inclination or vertical slope of the facing surfaces of vane15, varies along the length of the vane. This is best seen with reference to the various cross-sections taken along the length of the vane15shown inFIGS. 5A-5H. For example, it is seen that the inclination of surface21is relatively shallow at Section A-A (FIG. 5A) (as it is at Section H-H (FIG. 5H) for opposite surface23.) The angle of inclination of surface21gets progressively larger at Sections B-B (FIG. 5B) through Section H-H (FIG. 5H) where it reaches a maximum—almost vertical—inclination. Correspondingly (and in reverse symmetrical relationship), the angle of inclination of opposite surface23gets progressively larger at Section H-H (FIG. 5H) through Section A-A (FIG. 5A), where it reaches a maximum—almost vertical—inclination. As seen inFIGS. 5A-5I, in the illustrated embodiment, the inclinations of the surfaces at any given section are constant, to thus provide a profile with straight sides. Recessed regions or undercuts that would complicate forming the pieces by molding are avoided in this embodiment. In other possible embodiments, the inclination angle could also vary from top to bottom.

By virtue of the varying inclination angle along the length of the vane, the lateral angles of incidence are also non-uniform. Referring again to the cross-sections ofFIGS. 5A-5I, it can be seen that for any point along surface21above the rectangular base17, the front-to-back spacing of the point from the corresponding edge of the base of the vane will vary in relation to the height of the point and as a function of the inclination angle. Thus, proceeding along the length of the surface along a line spaced a given distance above the base, the front-to-back displacement of the surface portion from the base edge decreases as the angle of inclination increases, effectively resulting in a skewed surface orientation that can convey load items longitudinally, with a mount of the vane in alignment with the rotation axis of the drum11.

Since the opposing complex surfaces21and23themselves are complimentary of each other, the vane15exhibits reverse symmetry about both longitudinal and transverse center lines of the vane15. Therefore, the vane may be mounted in the drum11without regard to the directions of the surfaces. Regardless of the end of the vane positioned to the rear of the drum, an identical arrangement of facing surfaces will be presented. With the illustrative vane embodiment, a clockwise rotation will, in addition to tumbling the laundry load, also tend to convey items of the load toward the rear of the dryer drum11. A counterclockwise rotation will tend to convey the load forwardly within the drum11. The front-to-back orientation neutrality of the illustrative vane simplifies assembly, since the vane can be inserted in either direction.

Axial conveyance of the laundry via the vanes15may serve multiple purposes. For example, as described in detail below, directing the laundry towards the rear of the drum11can provide more effective use of a moisture sensor10as diagrammatically depicted inFIG. 2, which may be provided in the form of conductive strips mounted within the drum on the rear bulk-head. The strips form an open circuit which is closed by contact with wet or damp clothing (an arrangement generally known in the art). In a typical arrangement, a controller ascertains the dryness level of the clothes based upon changes in resistance caused by contact with wet or damp clothing. By urging the pieces of the dryer load rearwardly within the drum11toward the moisture sensor, the accuracy of the dryness determinations can be improved. This can lead to improved efficiency of the dryer in terms of energy expended, and save the user time and expense.

Directing the laundry to the rear of the dryer drum11during tumbling can also serve to reduce noise and improve airflow during the operation of the dryer1. For example, as explained earlier, in a typical arrangement, the air flowing through the dryer1enters through a duct at the rear (near the top rear portion of the drum) and exits though a duct at the front side (near the front lower portion of the drum). Such air flow tends to direct the laundry toward the lower portion of the front of the drum where the outlet duct grill is positioned. Therefore, the outlet duct can become clogged by the laundry. A conventional tumbling action of the drum may unclog the vent as the laundry is lifted by the vanes of the dryer. This periodic clogging and unclogging of the duct can create air flow surges that contribute a periodic noise to the overall noise generated by the operation of the dryer. Such a periodic or intermittent noise can be more objectionable than a continuous monotone noise which can be potentially “tuned out” by the user. An advantage of dryer vanes15according to the invention is that they can be used to direct the laundry load rearwardly away from the outlet air duct to substantially eliminate clogging/unclogging of the duct and the attendant air surge noise.

Although the complex angled vane surfaces21and23can be advantageously used to direct laundry axially and thereby provide the above described benefits, such surfaces may not, by themselves, “grip” the laundry quite as effectively as other vane styles presenting paddle-like or primarily radially directed contact surfaces which are not angled or tapered. For example, consider a vane which extends radially from the inner surface of the drum towards the center of the drum at an angle perpendicular to a tangent line of the cylindrical drum surface. In general, such a vane would be able to easily grip and lift the laundry due to its perpendicular angle.

On the other hand, as has been described, the twisted vane15has complex surfaces21and23including portions with varying degrees of inclination and lateral angles of incidence. Without some further provision, the complex angled surfaces21and23of the twisted vane15with less slope may not grip the laundry as well for tumbling as the parts of the vane with more slope. The difference in the slope along the vane15can affect the overall effectiveness of the vane15in tumbling the load. For example, end portion25of the angled surface21may not grip the laundry as well as the relatively steeper end27portion of the same surface21. See, e.g.,FIG. 4A-4C. The laundry will tend to slip along surface21more readily toward end25where there is less slope and therefore less grip, as compared to a surface portion adjacent end27where there is a greater slope and thus more grip. Further, even if the laundry were initially caught during the rotation of the drum11by the more vertically sloped portions of the vane15, such as near end27, due to the non-zero lateral angle of incidence serving to convey the load axially, the laundry will tend to be conveyed to the less vertically sloped portions of the vane15at the far end25, and therefore become more prone to slipping off the vane15resulting in less effective tumbling.

In accordance with an aspect of the invention, grip enhancing elements31are added to the surface of vane15to alleviate such slippage and thereby improving tumbling efficiency. Preferably, the amount of grip enhancement provided is varied in at least general relation to the degree of inclination of the vane surface at any given point. One method of varying the amount of grip enhancement along the complex surfaces of the different areas of the “twisted” vane15is to provide the differently inclined areas with differently sized or configured gripping elements31. This can be accomplished, for example, by providing protruding grip or traction elements31that vary in height, i.e., degree of protrusion from the respective inclined surface portions. For example, taller (more aggressive) grip elements31may be positioned in the less inclined areas of the “twisted” vane15, while and shorter (less aggressive) grip elements31may be positioned on the more inclined areas of the “twisted” vane15. Hence, in this embodiment, the height of the grip elements31varies in relation to the angle of inclination, or slope, of the complex vane surface upon which the grip element is mounted.

This concept is demonstrated in the illustrative embodiment shown in FIGS.5and5A-H. Relatively taller protruding grip elements31aare provided in the areas of the vane with less inclination or slope while shorter grip elements31bare provided on the surface areas with greater inclination or slope. For example, as seen by comparingFIG. 5AandFIG. 5H, the height of the protrusion31aat complex surface portion21shown inFIG. 5Ais greater than that of protrusions31bon the much steeper portion of surface21shown inFIG. 5H. The taller protrusions31aprovide more friction or gripping capability to the areas of less inclination or slope, while the shorter protrusions31bprovide less friction or gripping capability to the areas of greater inclination or slope. By viewingFIGS. 5A-5Iin sequential order, it is seen that as complex surface21becomes more inclined, the grip elements31become shorter. Likewise, as opposite surface23becomes less inclined, the grip elements31thereon become taller or more pronounced.

As mentioned, where the slope of the vane surface is steeper, there is less need for the additional grip. By varying the heights of the grip elements in at least general relation to the slope of the vane surfaces, the gripping characteristics across the vane may be generally equalized or otherwise optimized. The heights of the grip elements may vary within a suitable range so that optimal grip along the complex surfaces is realized. It should be noted that in the illustrative embodiment shown in the drawings, the grip elements are provided with a relatively subtle variation in height, varying from being essentially flush with the surrounding surface up to a height of 0.030 inches across the length of the vane. The variation is seen more clearly with reference to FIGS.6and6A-C. The enlarged diagrammatic sections (ofFIGS. 6A-C) through grip elements A, B and C plainly show the height of the protrusions decreasing across the length of surface21, as the inclination of surface21increases. The invention contemplates greater variations in height as well. Additional embodiments of the vanes may have grip elements with heights that may range from zero to a height greater than 0.030 inches. In one embodiment, the height is limited so as not to exceed ½ of the minor diameter or width of the element.

Varying the height of the grip elements is not the only possible method of varying the grip at the differently inclined/sloped areas of the vane15. In one embodiment, grip elements31with higher coefficients of friction (which may or may not be flush with the surrounding surface) may be positioned in different areas of the vane15. For example, in one embodiment, the grip elements31may be differential grip elements comprising different materials or surface textures. Also, the grip elements31may be of different shapes which are dictated by desired laundry gripping characteristics and/or aesthetic appearance. For example, as illustrated, the grip elements31have the form of raised circular protrusions, but other shapes may be provided. Further, in lieu of, or in addition to, grip elements of different heights, the grip elements31could be positioned in “clusters” or concentrations at particular areas to achieve differential laundry gripping effects by varying the number or density of the elements. For example, in vane areas of lesser inclination or slope there may be a concentrated “cluster” of protrusions. While at the areas of the greater inclination or slope, there may be merely a few scattered protrusions. Such clustered protrusions may also vary in height.

As can be clearly seen inFIGS. 4A,4B and5, the grip elements31can be arranged in a series of lines. The lines of grip elements may extend substantially across the length of the complex angled surfaces21and23from one end to the other. As shown, two lines extend substantially completely across complex angled surface21of the vane15, while a third line extends across only a portion of the front complex angled surface21of the vane. Aesthetically, a particular arrangement of the grip elements31, such as in a series of lines, can mimic an arrangement of surface features provided in a vane of a matching automatic washing machine. Commonly, washing machines and dryers are sold as a matched set. Consumers may prefer to have the appliances which are aesthetically complimentary or which have a consistent or thematic appearance. By providing grip elements31in a manner similar to the arrangement of holes and/or other surface features in a corresponding washer's vanes, aesthetic consistency can be obtained, in addition to the operational advantages. It will be understood that a series of lines is not required, but rather various other patterns of grip elements may be employed.

The vanes may be integrally molded as a single piece, such as by injection molding, including the grip elements31. Alternatively, the grip elements31may be attached to the vane15after the vane has been formed. In the particular embodiment depicted inFIGS. 5B-5H, the vane15is formed as distinct pieces that are engaged with each other. More specifically, as shown, the vane15may be formed of an inner piece33that nests within, and is secured to, an outer piece35. As shown inFIGS. 5A-5H, the inner piece33may include the grip elements31and be engaged with the outer piece35to form the dryer vane15. In the embodiment depicted inFIG. 5A-Hthe grip elements31extend through apertures in the outer piece35.

In light of the foregoing disclosure and description of various arrangements, those skilled in the art will readily understand that various modifications and adaptations can be made without departing from the scope and spirit of the inventions defined by the following claims.