Patent Abstract:
A drum for use in a dryer is provided. The drum includes a plurality of segments joined axially to form the drum&#39;s cylindrical shape. The drum has a simple structure enabling the use of standardized segments to facilitate dryer manufacture by reducing production costs, increasing productivity, and reducing failure rates. The drum, which has a cylindrical shape, is composed of a plurality of segments, preferably, three, each arranged axially with respect to the axis of the drum. The drum includes a coupling mechanism, provided on each side edge of each segment, for joining the segments to form the cylindrical shape of the drum.

Full Description:
This application claims the benefit of Korean Application No. P2003-090093, filed on Dec. 11, 2003, which is hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to dryers, and more particularly, to a drum for use in a dryer, which is composed of a plurality of segments joined axially to form the drum&#39;s cylindrical shape. 
   2. Discussion of the Related Art 
   Generally, a dryer uses hot air to dry laundry that has been washed. The dryer basically includes a drum for processing the laundry, a heating unit for supplying the drum with heated air, and an air discharging unit for expelling the hot air from the drum. 
     FIG. 1  illustrates a drum for use in a general dryer. The drum  10 , provided with a drying chamber  5  to accommodate laundry, is installed within an outer case (not shown) of the dryer, to be slowly rotated by a belt (not shown) wound in a belt groove  2  formed in the drum&#39;s outer surface. At least one lifter  12 , installed lengthwise on the inner surface of the drum  10 , is provided to raise the laundry in the drying chamber  5  to a predetermined height as the drum rotates, at which point the laundry falls in a tumbling action, to thereby evenly expose the laundry to hot air and assist in drying. 
   To fabricate the above drum, a thin plate of metal such as stainless steel is rolled into a cylindrical shape, or drum, and is welded at the edges to create a seam. To reinforce the strength of the drum, a die is used to press the welded drum and thus expand predetermined portions of the drum&#39;s periphery. The lifters, which are typically made of plastic and are separately fabricated, are then coupled to the drum&#39;s inner surface. 
   Fabricating such a drum, however, requires very large machinery, e.g., a press, which necessitates an expensive facility and high capital equipment investment. A complicated process inherently lowers productivity and increases failure rates. Also, since the drum is made of steel, unpleasant levels of noise are generated by the tumbling laundry, which tends to have metallic accessories and hard buttons that collide with the inner surface of the rotating drum. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to a dryer that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
   An object of the present invention is to provide a drum for use in a dryer, in which the drum has a simple structure enabling the use of standardized segments to facilitate dryer manufacture. 
   An object of the present invention is to provide a drum for use in a dryer, which enables reduced production costs and facilitates mass production. 
   Another object of the present invention is to provide a drum for use in a dryer, which increases productivity while reducing failure rates. 
   A further object of the present invention is to provide a drum for use in a dryer, which reduces noise levels generated during drying. 
   Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
   To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a drum for use in a dryer for drying laundry, wherein the drum has a cylindrical shape and is comprised of a plurality of segments. Herein, the segments are each arranged axially with respect to an axis of the drum. Preferably, the drum includes three segments. 
   The drum further includes coupling means, provided on each side edge of each segment, for joining the plurality of segments to form the cylindrical shape of the drum. The coupling means includes a pair of overlapping extensions respectively formed at mating side edges of each segment. 
   Each segment has the same size and shape and thus can be standardized, with each segment having a predetermined curvature based on a diameter of the drum. Each segment comprises at least one lifter for lifting laundry, which is integrally formed with the segment thereby being positioned the same on each segment, preferably, along one side edge of each segment. Preferably, the segments are made of a reinforced plastic material and are formed by injection molding. 
   In another aspect of the present invention, there is provided a dryer having a cylindrical drum, wherein the drum includes a plurality of segments, each segment having an arc shape for forming the drum, and coupling means for joining the plurality of segments to form the drum. 
   Herein, the drum further includes a plurality of lifters corresponding to the plurality of segments, each lifter being integrally formed with a corresponding segment. 
   In a further aspect of the present invention, a dryer includes a rotatable drum, composed of a plurality of segments, for drying laundry, a heating unit for generating hot air and supplying the rotatable drum with the hot air to dry the laundry, and an air discharging unit for expelling the hot air from the rotatable drum. 
   It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
       FIG. 1  is a perspective view of a drum of a general dryer; 
       FIG. 2  is a perspective breakaway view of a dryer adopting a drum according to the present invention; 
       FIG. 3  is a sectional breakaway view of a drum according to one embodiment of the present invention; 
       FIG. 4  is a sectional view of the drum of  FIG. 2 ; and 
       FIG. 5  is a sectional view of a drum according to another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
   Referring to  FIG. 2 , illustrating a dryer adopting a segmented drum according to the present invention, a drum  100 , provided with a drying chamber  50  to accommodate laundry, is installed within an outer case (not shown) of the dryer, to be slowly rotated by a belt (not shown) wound in a belt groove  20  formed in the drum&#39;s outer surface. A plurality of lifters  120 , formed lengthwise on the inner surface of the drum  100 , is provided to raise the laundry in the drying chamber  50  to a predetermined height as the drum rotates, at which point the laundry falls in a tumbling action, to thereby evenly expose the laundry to hot air and assist in drying. 
   A front head  7  and a rear head  9 , respectively installed at each end of the drum  100 , provide support for the ends of the rotating drum. Here, the drum  100  may have open ends, but the rearward end may be a closed end per product specification. Sealing members  8  for preventing leakage are respectively installed between the drum  100  and the front and rear heads  7  and  9 . 
   An air discharging unit, for expelling heated air for drying the laundry, is installed at a lower end of the inlet port  8  of the front head  7  to discharge air from the drying chamber  50 . The air discharging unit includes an outlet port assembly  13 , a lint filter  14 , a lint duct  15 , a blower  17 , and a discharging pipe  19 . The lint filter  14  is installed at the outlet port assembly  13  and filter foreign material from the air exiting the drying chamber  50 . The lint duct  15  is installed to communicate with the outlet port assembly  15 . The lint filter  14  is disposed over the intake of the lint duct  15  and the outlet port assembly  13 . The blower  17  is connected with the lint duct  15 , thereby sucking internal air of the drying chamber  50  through the lint duct  15 . The blower  17  is installed within a blower housing  18 . The blower housing  18  has one end communicating with the lint duct  15  and the other end connecting with the discharge pipe  19 . Accordingly, the blower  17  discharges air, which passes through the lint duct  15  from the drying chamber  50 , through the discharge pipe  19 . 
   A heating unit is installed at the rear head  9  to heat and supply air to the chamber  50  of the drum  100 . For the heating unit, an air supplying duct  12  is installed at the rear head  9 . The air supplying duct  12  functions as a passage through which the heated air is supplied to the drying chamber  50 . A hot air duct  25  is connected with the air supplying duct  12 . The hot air duct  25  induces hot air to be used inside the drying chamber  50 . For this, a gas nozzle  22  comprised of a gas burner  21  is installed at an inlet port of the hot air duct  25 . The gas nozzle  22  sprays the supplied gas. The gas nozzle  22  includes a valve for controlling the supply of the gas via a gas pipe  23 . A mixing unit  24  is extending from the inlet port to the intake of the hot air duct  25  to aerate the gas sprayed from the gas nozzle  22  by mixing the gas with external air introduced through an inlet port. A spark plug  26  is installed at a front end of the mixing unit  24  to generate an ignition spark. 
   Referring to  FIG. 3 , illustrating a drum for use in a dryer according to one embodiment of the present invention, the drum  100  includes a plurality of segments  110 , to be coupled to one another (or linked) as shown in  FIG. 4 . The segments  110  are arranged lengthwise (or axially) with respect to the drum  100  and are coupled using a plurality of coupling means, which are also arranged axially. 
   Each segment  110  is comprised of a plate member having a predetermined curvature (or arc) based on the diameter of the drum, such that, when assembled, the segments substantially form a circle, i.e., a cross-section of a cylinder, corresponding to the cylindrical shape of the drum  100 . Though fabricated as separate components, the plate members are roughly equivalent to pieces that would result from axially splitting a single-bodied cylindrical drum into a number of equal-sized pieces. According to the present invention, the segments  110  all have the same size and shape, so that a specification of the segments can be standardized, which facilitates mass production of the segments through a simple and repeatable process. 
   Furthermore, due to the segmentation of the drum  100 , the lifters  120  may be integrally formed with the segments  110 , and each lifter  120  may be formed at the same position of a corresponding segment, preferably, to be disposed along one side of the segment. Thus, the number of lifters preferably corresponds to the number of segments  110 . Such an integrated formation of the segments is in contrast to a conventional drum having a unified structure necessitating separately fabricated and subsequently installed lifters, which are coupled to the drum using a plurality of coupling members. In manufacturing a dryer adopting a drum according to the present invention, the present invention obviates the need for a separate coupling step for each lifter. Accordingly, the plurality of lifters  120  can be provided while maintaining the same, standardized size and shape of the segments  110 . 
   Though the segments  110  can be fabricated by any one of various methods, a standardized specification of the segments enables their fabrication through casting, which requires relatively little production equipment, as known in the art, and is suitable for mass production. In other words, the segments  110  can be molded in a single mold for integrally forming the lifters  120 . No large machine tools are required. 
   The drum  100  is preferably formed of a reinforced plastic material, which is lightweight and still exhibits high strength and is therefore more advantageous than steel. Furthermore, no excessive noise is generated when laundry collides with the inner of surface a plastic drum. In cases where the reinforced plastic material is applied, the segments are preferably manufactured using injection molding, which is more effective than plastic casting. 
   The number of segments  110  is preferably three. If the drum  100  is composed of just two segments  110 , each segment has a relatively large curvature, which encumbers the molding or casting and reduces the precision of the resulting segment, while a drum having more than three segments unduly encumbers the assembly of the drum and slows production accordingly. 
   To assemble the drum  100 , the segments  110  are coupled using a coupling means. The drum  100  is provided with a plurality of such coupling means along the axial length of the drum. 
   In the embodiment shown in  FIGS. 3 and 4 , the coupling means comprises a pair of overlapping extensions  130   a  and  130   b  provided at the mating side edges of the segments, which are respectively provided with coupling holes  131   a  and  131   b,  for receiving a coupling member  132 , such as a screw or bolt. When the segments  110  are combined to form the cylindrical shape of the drum  100 , the coupling holes  131   a  and  131   b  are aligned, and accordingly, one of the coupling holes is threaded, preferably, that ( 131   a ) of the inner extension  130   a.    
   In the embodiment shown in  FIG. 5 , the segments  110  are directly coupled, i.e., without a coupling member, by overlapping a pair of extensions  134   a  and  134   b,  which are respectively provided with a pair of opposing hooks  133   a  and  133   b.  Thus, the segments  110  are coupled at the mating side edges by engaging the hooks  133   a  and  133   b,  e.g., with a snap fit, or by fusing the mating surfaces using a heat source such as a laser. 
   As described above, a drum according to the present invention is composed of a plurality of segments, which are standardized to have the same size and shape, that is, the same specification, thus reducing the production costs of such a drum and facilitating its mass production. Owing to the production of standardized segments using casting techniques, no large machine tools are required, which reduces capital equipment costs and simplifies the overall manufacture process. Therefore, improved productivity and reduced defective rates can be anticipated, which further reduces production costs. 
   It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Technology Classification (CPC): 3