Patent Publication Number: US-6215956-B1

Title: Reciprocating radiant electric heater

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electric heater generally used for heating a space in a building, and more particularly, to an improvement to the electric heater of the Korean Utility Model Application No. 1997-5769 of the same inventor as that of the present invention. 
     2. Description of the Prior Art 
     An electric heater disclosed in the Korean Utility Model Appln. No. 97-5769 is designed to radiate heat generated from an electric heating wire a long way off by using a spherical reflector (for example, a parabolic type), thereby obtaining an optimal energy efficiency. 
     The reflector of the electric heater, however, is permanently fastened at a post on a stand and thus a user must reach or get to the heater and manually change the direction to which the reflector faces, whenever the user wants to change the direction of the heat radiation. 
     Moreover, the heater could hardly warn a room or space uniformly in a short period of time, if it were left to radiate heat only in one direction. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide an electric heater which can warm a space uniformly in a relatively short period of time. 
     Another object of this invention is to provide an electric heater which is very convenient and simple to use. 
     The above objects can be accomplished by providing an electric heater which can alternately change the lateral direction of the heat radiation from left to right and then from right to left by means of a reflector rotating device. 
     The present invention provides an electric heater with a post and a heating member; which comprises an orientation device comprising a pole or spindle fixed on the post; a movable plate formed with front and rear holes and rotatably mounted on the pole or spindle through the front hole, carrying the heating member; a geared motor with a shaft extending downwardly through the rear hole of the movable plate; a transmission plate formed with mating teeth on the upper surface and rotatably fixed to the lower end of the motor shaft; a driving plate carrying a guide pin on or near its lower edge and formed with mating teeth in a groove on its bottom surface to be engaged with the counter part of the transmission plate; a spring mounted around the motor shaft under the movable plate for elastically pressing the driving plate downwardly; and an elongate guide path formed on the post for receiving the guide pin obliquely relative to the pole or spindle and allowing it to reciprocate straightly therein. 
     Therefore, when a user turns on a switch of the rotating device, the reflector performs a continuous reciprocating motion in an adequate speed within the range of the predetermined angle, thereby radiating heat generated from the heating wire uniformly within a room or space to be heated or warmed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a perspective view of an electric heater to which the present invention is applied; 
     FIG. 2 is a perspective view, partly disassembled, of an electric heater with a rotating device according to a preferred embodiment of the present invention; 
     FIG. 3 is an exploded perspective view of a driving plate and a transmission plate of the orientation device of FIG. 2; 
     FIGS. 4 a  and  4   b  are side views partly taken in section showing the operation of the orientation device of FIG. 2; 
     FIGS. 5 a  through  5   c  are plan views, partly taken in section, showing the operation of the parts of the orientation device; and 
     FIG. 6 is a plan view, partly taken in section, showing the lateral movement of the reflector. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will be described in detail hereinafter with reference to the accompanying drawings, wherein the same reference numerals designate the same parts. It is to be understood that these drawings depict only a typical embodiment of the invention and are, therefore, not to be considered limiting its scope. 
     A heating element, which is indicated generally by the reference numeral  10 , includes a ceramic tube  11  and an electric heating wire  12  wound on the ceramic tube  11 . 
     The heating element  10  is mounted on the front central portion of a spherical reflector  20 . The reflector  20  is arranged on the upper end portion of a post  40  so that the inclination of the reflector  20  may be adjusted by a head  30  mounted at the rear part of the reflector plate  20 . 
     The post  40  is mounted on a stand  50 , which generally includes an on-off switch  51  for the heating wire  12 , a reciprocating switch  52  for the reflector  20  and a timer  53  for setting heating time. 
     The head  30  includes a body case  31  pivotally mounted on the upper end portion of the post  40  by a usual inclination adjuster of the reflector  20  and a over  32 , which is coupled to the upper portion of the body case  31 . The head  30  further includes a orientation device  60  inside the head  30  for enabling lateral reciprocating rotation of the reflector  20  within an angle of a predetermined range. 
     The orientation device  60  includes an L-shaped movable plate  61 , a vertical portion of which is fastened at the rear central portion of the reflector  20 ; a pole or spindle  62  for allowing a front portion of the horizontal portion of the movable plate  61  to be pivotally mounted on the body case  31 ; a geared motor  63  fixed on the rear upper surface of the horizontal portion of the movable plate  61 ; a transmission plate  64  fixed to the lower end of a motor shaft  631  which pierces through the horizontal portion of the movable plate  61  and is exposed downward; a driving plate  65  carrying a guide pin  652  at its edge and formed with a circular concave  651  at the center of its bottom side for receiving the transmission plate by therein; a elastic spring  66  mounted around the motor shaft  631  between the horizontal portion of the movable plate  61  and the plate  65  and for allowing the driving plate  65  to rotate with the transmission plate  64  by elastically pressing the driving plate  65  toward the transmission plate  64 ; and an elongate guide path  67  obliquely formed inside the upper portion of the body case  31  for receiving the guide pin  652  and allowing the pin  652  to reciprocate straightly therein. 
     A plurality of mating teeth  641  and  653  are formed on the upper surface of the transmission plate  64  and the surface of the circular concave of the driving plate  65  respectively to be engaged with each other. 
     The driving plate  65  engages the transmission plate  64  at the influence of the downward elasticity of the spring  66  and by the engagement of the teeth  641  and  653  and thus rotates simultaneously with the transmission plate  64 . 
     However, if the downward elastic power of the spring  66  is prevented to work the engagement of the driving plate  65  with the transmission pate  64  becomes loose, resulting in an idle rotation of the transmission plate  64  without making the driving plate  65  to rotate. 
     The electric heater according to the preferred embodiment of the present invention operates as follows: 
     First, when a user turns on a switch  51  to operate the heating element  10 , the electric heater is supplied with power and the heating wire  12  generates heat. 
     The user may limit the heating time by manipulating a timer  53 . If the user bends the reflector  20  or the head  30  upward or downward, the direction of the heat radiation of the reflector  20  is adjusted by the operation of the inclination adjuster  41 . 
     Furthermore, when the user turns on the reciprocating switch  52 , the reflector  20  continuously performs the lateral reciprocating movement. 
     When the geared motor  63  is supplied with power, the motor shaft  631  is rotated by the operation of the motor so that the transmission plate  64  mounted on the lower end of the motor shaft  631  may be rotated. 
     As shown in FIG. 3, since the transmission plate  64  is received in the circular concave  651  of the driving plate  65  lowered by the elasticity of the spring  66 , the rotating power of the motor  63  is transmitted to the driving plate  65  by the elasticity of the spring and the engagement of the teeth  641  and  653 , resulting in rotation of the driving plate  65 . 
     When the driving plate  65  is rotated, the guide pin  652  protruded downward from the lower surface and inserted into the guide path  67  obliquely formed on the body case  31 , is not moved in the rotational direction of the driving plate  65 , but moved in the oblique direction along the guide path  67 . 
     Therefore, the rotating motion of the motor  63  is converted into a rectilinear movement of the guide pin  652  through the guide path  67 , and thereby the guide pin  652  is reciprocated along the guide path  67  on a same cycle as the driving plate  65  rotates. The guide pin  652  can manage to move smoothly by virtue of a ring  654  mounted thereon. 
     Because the guide pin  652  moves rectilinearly while the driving plate  65  rotates, the motor shaft  631  revolves around the axis of the guide pin  652 , thereby the rear part of the horizontal portion of the movable plate  61  on which the motor shaft  631  is arranged rotates in the same direction as the revolution of the motor shaft  631 . Thus, as shown in FIG. 5 c  and the FIG. 6, the reflector  20  mounted on the vertical portion of the movable plate  61  reciprocates between the extreme points in the right and left. The motor shaft  631  and the pole  62  are aligned on the center line(q) and thus the reflector  20  faces the front, when the guide pin  652  is located in the rear part of the guide path  67 . 
     In this state, as the guide pin  652  is moved to the central part of the guide path  67  by the rotation of the driving plate  65 , the motor shaft  631  is moved to the left of the pole  62 . The vertical portion of the movable plate  61  is rotated clockwise on the axis of the pole  62  in the right direction, thereby the reflector  20  is pivoted to the right. 
     After that, as the guide pin  652  is moved from the central portion to the front portion of the guide path  67  by the continuous rotation of the driving plate  65 , the motor shaft  631  is moved and located on the central line(q) to be aligned with the pole  62  as shown in FIG. 5 b  and FIG. 6, thereby the reflector  20  is pivoted to the front. 
     When the guide pin  652  returns from the front portion to the central portion of the guide path  67  by the continuous rotation of the driving plate  65 , the motor shaft  631  is moved counterclockwise as shown in FIG. 5 c.  As the front portion of the movable plate  61  is rotated counterclockwise, the reflector  20  is pivoted to the left. 
     When the guide pin  652  is moved from the central portion to the rear portion of the guide path  67  by the continuous rotation of the driving plate  65 , the motor shaft  631  is moved and aligned with the center line(q) and the pole  62  so that the reflector  20  may be moved clockwise and face the front, whereby returning to the position as shown in FIG. 5 a.    
     By the above operation, the reflector  20  reciprocates once between the extreme positions in the right and left, as the driving plate  65  is rotated once by the motor  63 , thereby resulting in automatic reversing of the heat radiating direction. 
     Meanwhile, if the user holds the reflector with the hand during its lateral rotation or rotation of the reflector is blocked by some other means, the movable plate  61  carrying the reflector  20  cannot rotate, but the transmission plate  64  is forced to keep rotating by the motor  63 , whereby the driving plate  65  can not rotate and thus the guide pin  652  cannot move inside the guide path  67 . 
     As the transmission plate  64  is forced to keep rotating by the motor  63 , the rotating power of the motor  63  acts to break the mating engagement of the clutch teeth  641  and  653  of the transmission plate  64  and the driving plate  65 . As the rotating power of the motor  63  exceeds or overpowers the elasticity of the spring  66 , the teeth  641  and  653  are forced to be disengaged as shown in FIG. 3 b.  The driving plate is thus pushed up in proportion to the height or depth of the teeth  641  or  653 , making the spring  66  compressed and thus the transmission pin  64  keep rotating with the teeth  641  and  653  alternating between being engaged and disengaged. Therefore, the reciprocating device  60  including the motor is protected from being damaged. The reflector can also be manually pivoted on the pole  62 , even when the motor  63  is operating. 
     As described above, the user can automatically and easily convert the direction of heat reflection of the reflector, thereby achieving the objects of the invention. 
     Those skilled in the art will readily recognize that various revisions, modifications and changes may be made to the present invention which has been described by way of example without departing from the spirit and scope of the present invention. The scope of the protection of the invention may be limited only by the appended claims.