Clothes Dryer With Unitary Bulkhead

The field of the invention generally relates to tumbler clothes dryers, and more particularly relates to clothes dryer bulkheads and a method of manufacturing such bulkheads.

As is well known in the art, tumbler clothes dryers typically have a horizontally disposed tumbler cylinder or drum that is rotated by a belt drive to tumble the clothes inside the drum. In the normal arrangement, the ends of the drum are covered by stationary panels commonly referred to as bulkheads which serve a number of functions. First, the bulkheads serve to retain the clothes within the drum. Second, the bulkheads provide a substantially air tight seal so that hot air can be drawn through the drum. Third, the drum is supported by bearings which are mounted to the bulkheads.

Prior art bulkheads are typically constructed by stamping a metal blank to form a disc or panel that has a raised cylindrical plug portion which is sized to be surrounded by a sealing gasket and then inserted into an end of the drum. Mounting brackets are mounted to peripheral side portions of the disc by a fastening technique such as welding, and a pair of suitable drum support bearings such as rollers or glide pads are attached to lower peripheral regions of the disc. In fabrication, the rear bulkhead is attached to the back panel of the dryer cabinet by inserting screws through the mounting brackets which have stand-off legs to provide a heater box space between the bulkhead and the cabinet back panel. After the drum is properly supported on the rollers and positioned around the gasket of the rear bulkhead plug portion, the plug portion of the front bulkhead is inserted into the front end of the drum, and then the mounting brackets of the front bulkhead are screwed to the front edges of the side panels of the dryer cabinet.

In one typical prior art arrangement, the pair of drums support bearings (e.g. rollers or glide members) are mounted to the disc at respective locations approximately 45.degree. and 30.degree. up from the bottom with the higher mounting location being in the direction of rotation of the drum. The mounting brackets, which are relatively small and have relatively small vertical span to reduce complexity, size, and cost, are attached to respective mid-level portions of the disc at approximately 90.degree. up from bottom with screws that are only slightly above and below the 90.degree. positions.

There are serious drawbacks with the above described bulkhead assembly and method of manufacture. First, with the mounting brackets being welded to the disc or panel, there is the cost of labor involved in the welding process, as well as the cost for additional parts. Further, the welding process increases the dimensional tolerances of the bulkhead assembly thereby sometimes making it difficult to mount the bulkhead to the cabinet panel. For example, the bulkhead or the cabinet panel may have to be flexed or bowed to align the corresponding screw holes, and this dimensional instability detracts from the rigidity of the dryer. Also, because the mounting brackets are made relatively small to minimize cost, the assembly is relatively weak and is susceptible to bending, flexing, or vibrating. Further, there are relatively large moment arms between the rollers or glide pads that support the drum and the mounting locations of the mounting brackets. Thus, the disc may have a tendency to deflect or vibrate.

It is an object of the present invention to provide an improved bulkhead for use with a tumbler clothes dryer.

It is an also object to provide a bulkhead and method of manufacturing the same that reduces the parts, materials, and labor.

It is a further object to provide a bulkhead that is more rigid and has improved dimensional stability to reduce bending, oil canning, and/or vibration.

Another object is to provide a bulkhead that effectively and efficiently absorbs and transmits the rotational forces of the drum to the dryer's cabinet.

It is a further object to provide a bulkhead that minimizes the moment arms between the drum supporting bearings and the mounting brackets to the cabinet panel.

It is a further object to provide a bulkhead that includes surface area for readily and conveniently mounting clothes dryer components.

In accordance with the invention, a method of fabricating a bulkhead for a clothes dryer having a tumbler drum comprises the step of forming a bulkhead panel from a single metal blank wherein the bulkhead panel comprises a circular plug portion adapted for insertion into the drum and a mounting bracket extending from each quadrant of the plug portion. The method may also include the step of attaching drum bearings to the bulkhead panel. It is preferable that the method further include the step of attaching a sealing gasket around the circular plug portion before insertion into the drum. Further, the forming step may preferably comprise a plurality of stamping steps on a progressive die. Each of the mounting brackets may comprise a face portion joined to the circular plug portion, a leg portion joined to a respective one of the face portions and extending substantially perpendicular thereto, and a foot mounting portion joined to the leg portion and extending substantially parallel with the circular plug portion. Each of the drum bearings may comprise a roller attached to a respective one of the face portions. Alternately, each drum bearing may comprise a glide pad.

The invention may also be practiced by a method of fabricating a clothes dryer comprising the steps of forming a tumbler drum, stamping from respective single metal blanks front and rear bulkhead panels each comprising a circular plug portion and a mounting bracket joined to and extending from each of the four quadrants of the plug portion. Each of the mounting brackets comprises a face portion joined to and extending substantially parallel to the circular plug portion, a leg portion joined to a respective one of the face portions and extending substantially orthogonal thereto, and a foot mounting portion connected to a respective one of the leg portions and extending substantially parallel to the plug portion. The method further comprises connecting tumbler drum bearings to lower ones of the face panels on each of the rear and front bulkhead panels, forming a cabinet having a back panel and parallel opposing side panels, and then mounting the rear bulkhead panel to the back panel of the cabinet by connecting the foot mounting portion of each of the mounting brackets to the cabinet back panel. The method further comprises the steps of positioning the tumbler drum around the plug portion of the rear bulkhead panel with the tumbler drum being supported on the drum bearings of the rear bulkhead panel, inserting the plug portion of the front bulkhead panel into the front end of the tumbler drum with the tumbler drum resting on the drum bearings of the front bulkhead panel, and attaching the foot mounting portions of the mounting brackets of the front bulkhead panel to the side panels of the cabinet.

In accordance with another aspect of the invention, a bulkhead for a clothes dryer having a tumbler drum comprises a bulkhead panel formed from a single metal blank, such panel comprising a circular plug portion adapted for insertion into the drum and a mounting bracket extending from each quadrant of the plug portion, and drum bearings attached to the bulkhead panel.

With such arrangement, the mounting brackets are formed as part of the stamping process so the prior art step of attaching the mounting brackets by welding is eliminated. Further, the size of a substantially rectangular metal blank is optimized by forming the mounting brackets from corner regions of the blank such that one mounting bracket is formed in each quadrant of the circular plug portion. One advantage of such arrangement is that there is dimensional stability or consistency between the mounting brackets so that they can be easily and readily aligned with corresponding mounting apertures in the back panel of the cabinet without bending or flexing either part. Also, the moment arms between the drum bearings and mounting brackets are reduced so that the force of the tumbler drum is better absorbed and transferred to the dryer cabinet than with prior art apparatus. Also, with the heretofore described arrangement with a mounting bracket in each quadrant of the plug portion, the bulkhead is more rigid and less likely to flex; therefore, there is less fatigue stress. Further, mounting brackets provide a convenient surface for mounting dryer components such as an electrical terminal block.

The foregoing objects and advantages will be more fully understood by reading the description of the preferred embodiment with reference to the drawings wherein:

FIG. 1 is a front view of a rear bulkhead;

FIG. 2 is a sectioned view taken along line 2--2 of FIG. 1;

FIG. 3 is a rear view of a front bulkhead;

FIG. 4 is a side view of the bulkhead of FIG. 3;

FIG. 5 is a front perspective view of a tumbler clothes dryer partially disassembled; and

FIG. 6 is an expanded view of circle 6--6 of FIG. 5.

Referring to FIGS. 1 and 2, front and sectioned side views respectively show rear bulkhead 10 which includes bulkhead panel 12, drum bearings 14a and b, and sealing gasket 16. In accordance with the invention, bulkhead panel 12 is fabricated as a unitary part by stamp forming from a single metal blank. In particular, a progressive die is used, and the metal blank is sequenced along an eight station die run on a transfer press. Bulkhead panel 12 includes a cylindrical plug portion 18 and four mounting brackets 20a-20d which are connected to the cylindrical plug portion 18 and extend respectively from the four quadrants thereof. Each of the four mounting brackets 20a-d is disposed at an approximate mid-region of its respective quadrant. By such arrangement, the use of the metal blank is optimized thereby minimizing material; also, the four quadrant attachment of bulkhead panel 12 to back panel 74 (FIG. 5) makes bulkhead panel 12 stronger and more rigid. Cylindrical plug portion 18 is sized to insert in the rear end 22 of drum 24 (FIG. 5). As is conventional, cylindrical plug portion 18 has a heater input aperture 26 through which heated air is drawn into drum 24.

Each mounting bracket 20a-d has a face portion 28a-d, a leg portion 30a-d, and a foot mounting portion 32a-d. The face portions 28a-d extends substantially parallel from the cylindrical plug portion 18 in the lateral and up/down directions. The leg portions 30a-d connect to the respective face portions 28a-d and extend in the rearward direction to provide an offset space behind rear bulkhead 10 for the positioning of the heater element (not shown). The foot mounting portions 32a-d connect to the respective leg portions 30a-d and extend in the lateral directions substantially parallel to the face portions 28a-d.

As shown in FIG. 2, leg portions 32a-d here have formed ribs 33 or indentations to provide increased structural rigidity, and face portions 28a-d may also have such reinforcing structure.

After the stamping of bulkhead panel 12 as a unitary part on a progressive die from a single metal blank, bulkhead panel 12 is processed and painted in a conventional manner. Then, sealing gasket 16 is attached around the circumference of cylindrical plug portion 18, and tumbler or drum bearings 14a and b are attached to face portions 28b and c of the bottom two mounting brackets 20b and c. In particular, each drum bearing 14a and b here includes reenforcement housing 34, and a shaft 36a and b connected to a respective roller wheel 38a and b.

In an exemplary embodiment, cylindrical plug portion 12 has a diameter of approximately 24", leg portions 30a-d provide a standoff distance of approximately 2.5", respective screw holes 80c and d are vertically spaced by approximately 19", and respective screw holes 80a and b are vertically spaced by approximately 16". Further, roller wheel 38a is located 45.degree. clockwise from bottom while roller wheel 38b is located 30.degree. counter-clockwise from bottom. Such arrangement is optimized for counter-clockwise rotation of drum 24.

Referring to FIGS. 3 and 4, rear and side views show front bulkhead 40 to include a bulkhead panel 42, drum bearings 44a and b and sealing gasket 46. Like the rear bulkhead panel 12, the front bulkhead panel 42 is fabricated as a unitary part by a progressive die stamping process using a single metal blank. The front bulkhead panel 42 includes a cylindrical plug portion 48 and four mounting brackets 50a-d. As can be seen in FIG. 5, which shows a perspective view of dryer 52 with the front bulkhead 40 at the front, cylindrical plug portion 48 includes a large central access opening 54 which includes a tunnel portion 56 having lint filter aperture 58.

As with the rear bulkhead panel 12, each mounting bracket 50a-d of the front bulkhead panel 42 includes a face portion 60a-d, a leg portion 62a-d, and a foot mounting portion 64a-d. Each face portion 60a-d is connected to the cylindrical plug portion 48 and extends in the lateral and up/down directions substantially parallel to the cylindrical plug portion 48. The mounting brackets 50a-d are arranged at the approximate midpoints of the four respective quadrants so as to reduce the size of the required metal blank, and also to increase the rigidity after mounting to dryer cabinet 76 (FIG. 5). The leg portions 62a-d connect to the respective face portions 60a-d and extend in the forward direction. The foot mounting portions 64a-d connect to the respective leg portions 62a-d and extend in the lateral directions.

After the front bulkhead panel 42 is stamped as a unitary part from a single metal blank as described above, panel 42 is processed and painted or porcelainized in conventional manner. Then, sealing gasket 46 is attached around the circumference of cylindrical plug portion 48 and drum bearings 44a and b are attached to face portions 60b and c of the two bottom mounting brackets 50b and c. Roller wheels identical to roller wheels 38a and b of rear bulkhead 10 could be used for drum bearings 44a and b. Here, however, drum bearings 44a and b are glide assemblies and used as an alternate embodiment to optimize the cost of using roller wheels 38a and b for supporting drum 24 (FIG. 5) at the front. Each front drum bearing 44a and b includes a bracket 70a and b holding a respective glide pad 72a and b which preferably is fabricated of a low-friction wear-resistant material on which drum 24 rotates.

In an exemplary embodiment, screw holes 82a and b and 82c and d are vertically spaced approximately 15", respectively. Furthermore, screw holes may be horizontally spaced approximately 25". Thus, with mounting brackets 50a-d being somewhat uniformly spaced in the four respective quadrants of cylindrical plug portion 48, front bulkhead 40 like rear bulkhead 10, is a relatively rigid and secure structure when mounted to cabinet 76.

Referring to FIG. 5, there is shown a front perspective view of tumbler clothes dryer 52 with the front, top, and one side panel missing. Also missing are the controls and air flow apparatus which are conventional and not needed for an understanding of the present invention. In fabrication, the heater assembly (not shown) is screwed to the rear bulkhead 10, and then rear bulkhead 10 is mounted to the back panel 74 of the dryer cabinet 76. More specifically, locator tabs 78a and b extending from the bottom of foot mounting portions 32a and d as shown in FIG. 1 are inserted into corresponding slots (not shown) on back panel 74. Because bulkhead panel 12 including mounting brackets 20a-d is stamped, the spacing or relative location between locator tabs 78a and b is precisely fixed by the stamping die, and therefore the locator tabs 78a and b precisely align with the corresponding slots in back panel 74 which is also formed by stamping. In other words, if mounting brackets 20a and d were welded onto cylindrical plug portion 18 instead of being part of a unitary stamped part, the tolerance or dimensional spacing between locator tabs 78a and b could vary such that inserting locator tabs 78a and b into the corresponding slots could require bending or flexing either rear bulkhead 10 or back panel 74. Here, however, the dimensional tolerance is substantially eliminated and locator tabs 78a and b readily and easily slip into slots thereby supporting rear bulkhead 10 on back panel 74. Similarly, screw holes 80a-d readily align with corresponding screw holes (not shown) in back panel 74, and rear bulkhead is securely attached to back panel 74.

The rear rim 84 of drum 24 is then disposed around central plug portion 18 with sealing gasket 16 providing a substantially air tight but rotatable seal therebetween. The rear of drum 24 is supported by roller wheels 38a and b which are disposed at an approximately 45.degree. and 30.degree. , respectively up from bottom.

Belt 86 is then positioned around drum 24 an connected to belt drive 88 which is coupled to motor 90 mounted on base 92.

Front bulkhead 40 is then positioned at the front of drum 24 with cylindrical plug portion 48 and sealing gasket 66 inserted into drum 24 to provide a substantially air tight but rotatable seal. Locator tabs 94a and b insert into corresponding slots in the front edge of side panels 96 of cabinet 76. Thus, front bulkhead 40 is held in position for the attachment of screws through screw holes 82a-d into the front edges of side panels 96. Air flow apparatus (not shown) is connected to the underside of lint filter aperture 58 to draw heated air from the heater assembly (not shown) through the heater input aperture 26 and longitudinally to the front of drum 24 and out lint filter aperture 58. As is conventional, a portion of the air may be recirculated through the heat assembly with another portion being exhausted. As the hot air is drawn through drum 24, belt 86 rotates drum 24 and the clothes are lifted by vanes 100 to be tumbled through the hot air.

Referring to FIG. 6, an expanded view of circle 6--6 of FIG. 5 shows an electrical terminal block 102 mounted to the rear of face panel 28a of mounting bracket 20a. In particular, terminal block 102 here includes a dielectric housing 104 to which conductor strips 106a-f are attached and selectively interconnected to electrically connect attached wires (not shown) in conventional manner. The rear side of face portion 28a provides a convenient location for mounting terminal block 102 by inserting a screw 108 through the front of face portion 28a. The area is readily accessible for maintenance and repair, and avoids mounting such block 102 to the cabinet 76. As shown in FIG. 1, mounting bracket 20a and face portion 28a are slightly lower than corresponding mounting bracket 20d to provide more convenient access to terminal block 102.

In accordance with the invention, the stamping of rear and front bulkhead panels 12 and 42 as unitary parts from single metal blanks provides a number of advantages. First, the number of parts and the labor costs of assembling such parts is reduced. For example, the labor costs associated with the prior art method of welding mounting brackets 20a-d and 50a-d to respective cylindrical plug portions 18 and 48 are eliminated. Second, as described above, there is greater dimensional consistency or uniformity (i.e. less tolerance) between mounting brackets 20a-d and 50a-d because such dimensions are fixed by the stamping die rather than being dependent on a subsequent welding step that introduces variances. Thus, rear bulkhead panel 12 can easily and readily be mounted to back panel 74 without flexing either part to attain alignment of locator tabs 78a and b and screw holes 80a-d to corresponding apertures in back panel 74. As a result, there is improved rigidity of rear bulkhead 10. Third, by stamping bulkhead panels 12 and 42, mounting brackets 20a-d and 50a-d can be conveniently positioned at angular locations that are approximately centered in the four quadrants of respective cylindrical plug portions 18 and 48. More specifically, rather than welding a pair of mounting brackets at opposing mid-level regions (i.e. 90.degree. and 180.degree. ) as was done in the prior art to keep the mounting brackets relatively small and simple, it is advantageous to use four mounting brackets 20a-d and 50a-d on each bulkhead 10 and 40, and to locate a mounting bracket in each quadrant (e.g., at approximately 45.degree. , 135.degree. , 225.degree. , and 315.degree. ). With such arrangement, the size of the required metal blank is minimized. With each quadrant of bulkheads 10 and 40 being mounted to supporting structure i.e. back panel 74 and side panels 96, respectively), the bulkheads 10 and 40 are more rigid and less likely flex or bend at the top and bottom. Therefore, there is less fatigue stress. Also, with mounting brackets 20a-d and 50a-d located as described, the moment arms from drum bearings 14a and b and 44a and b to respective mounting brackets 20a-d and 50a-d are reduced. Thus, the mounting brackets 20a-d and 50a-d are better able to absorb and transmit the drum forces to the dryer cabinet 76; this also results in less fatigue stress on the front and rear bulkheads 10 and 40. Furthermore, the precise and fixed locations of mounting brackets 20b and c and 50b and c provides improved alignment for drum bearings 14a and b and 44a and b. Thus, there is less vibration and bouncing of drum 24 as it rotates. Finally, the heretofore described arrangement of mounting brackets 20a-d and 50a-d provides a convenient area for the mounting of electrical components.

The foregoing description of the preferred embodiment will bring to mind many modifications and alterations that do not depart from the spirit and scope of the invention. Accordingly, it is intended that the scope of the invention be limited only by the appended claims.