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.
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.
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.
The foregoing summary of the disclosure, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the accompanying drawings, which are included by way of example, and not by way of limitation with regard to the claimed invention.
An illustrative front-load automatic laundry dryer 1 is shown in
In a generally conventional manner, an air flow system draws air through a heater section 4 and into the drum 11 through a duct provided on the backside of a rear bulkhead 9 to which a rear side of the drum may be rotatably mounted. Preferably, air is drawn from inside of the housing into heater 4 to take advantage of heat exchange with the drum 11 and the heater. The air may be exhausted from the drum 11 through an outlet duct incorporated into the front drum-supporting bulkhead, which is concealed behind the front panel visible in
Referring now to
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 vane 15 which 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 surfaces 21 and 23, depending on the rotation direction of the drum. The end of the vane closest to the dryer door 5 (access port) may be considered the proximal end of the vane and the end of the vane farthest from the dryer door 5 may be considered the distal end of the vane.
As seen in
Opposing surfaces 21 and 23 also 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 vane 15 can, 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 vane 15 with a skew relative to the drum rotation axis.
As mentioned, the inclination or vertical slope of the facing surfaces of vane 15, varies along the length of the vane. This is best seen with reference to the various cross-sections taken along the length of the vane 15 shown in
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 of
Since the opposing complex surfaces 21 and 23 themselves are complimentary of each other, the vane 15 exhibits reverse symmetry about both longitudinal and transverse center lines of the vane 15. Therefore, the vane may be mounted in the drum 11 without 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 drum 11. A counterclockwise rotation will tend to convey the load forwardly within the drum 11. 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 vanes 15 may serve multiple purposes. For example, as described in detail below, directing the laundry towards the rear of the drum 11 can provide more effective use of a moisture sensor 10 as diagrammatically depicted in
Directing the laundry to the rear of the dryer drum 11 during tumbling can also serve to reduce noise and improve airflow during the operation of the dryer 1. For example, as explained earlier, in a typical arrangement, the air flowing through the dryer 1 enters 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 vanes 15 according 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 surfaces 21 and 23 can 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 vane 15 has complex surfaces 21 and 23 including portions with varying degrees of inclination and lateral angles of incidence. Without some further provision, the complex angled surfaces 21 and 23 of the twisted vane 15 with 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 vane 15 can affect the overall effectiveness of the vane 15 in tumbling the load. For example, end portion 25 of the angled surface 21 may not grip the laundry as well as the relatively steeper end 27 portion of the same surface 21. See, e.g.,
In accordance with an aspect of the invention, grip enhancing elements 31 are added to the surface of vane 15 to 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” vane 15 is to provide the differently inclined areas with differently sized or configured gripping elements 31. This can be accomplished, for example, by providing protruding grip or traction elements 31 that vary in height, i.e., degree of protrusion from the respective inclined surface portions. For example, taller (more aggressive) grip elements 31 may be positioned in the less inclined areas of the “twisted” vane 15, while and shorter (less aggressive) grip elements 31 may be positioned on the more inclined areas of the “twisted” vane 15. Hence, in this embodiment, the height of the grip elements 31 varies 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. 5 and 5A-H. Relatively taller protruding grip elements 31a are provided in the areas of the vane with less inclination or slope while shorter grip elements 31b are provided on the surface areas with greater inclination or slope. For example, as seen by comparing
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. 6 and 6A-C. The enlarged diagrammatic sections (of
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 vane 15. In one embodiment, grip elements 31 with higher coefficients of friction (which may or may not be flush with the surrounding surface) may be positioned in different areas of the vane 15. For example, in one embodiment, the grip elements 31 may be differential grip elements comprising different materials or surface textures. Also, the grip elements 31 may be of different shapes which are dictated by desired laundry gripping characteristics and/or aesthetic appearance. For example, as illustrated, the grip elements 31 have 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 elements 31 could 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 in
The vanes may be integrally molded as a single piece, such as by injection molding, including the grip elements 31. Alternatively, the grip elements 31 may be attached to the vane 15 after the vane has been formed. In the particular embodiment depicted in
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.