Patent Publication Number: US-7723652-B2

Title: Adjusting device for adjusting tension of heating straps on heating assembly

Description:
FIELD OF THE INVENTION 
   The present invention relates to an adjusting device for adjusting tension of heating straps on a frame of a heating assembly so as to prevent contact between the heating straps. 
   BACKGROUND OF THE INVENTION 
   A conventional heating assembly is shown in  FIGS. 1 and 2 , and generally includes a frame  1  with notches  102  defined in two insides of the frame  1  and a plurality of supports  2  each have two insertions  202  on two ends thereof, the insertions  202  are engaged with the notches  102  so as to connect the supports  2  across two sides of the frame  1 . Two positioning bars  3  are connected between two ends of the frame  1  so as to press the supports  2  in position. Each support  2  has a plurality of positioning recesses  204  and a separation portion  206  is located between adjacent positioning recesses  204 . A heating strap  4  is engaged with the positioning recesses  204  back and forth and the sections of the heating strap  4  between the supports  2  are separated by the separation portions  206  to avoid contact. When electric current goes through the heating strap  4 , the heating strap  4  generates heat due to resistance and the heat is spread by a fan to increase the temperature of the interior of a room. 
   However, the heating strap  4  inflates because of the high temperature and the area of cross section of the heating strap  4  increases. The adjacent sections of the heating strap  4  might be in contact with each other to cause short of the circuit. 
   The present invention intends to provide an adjusting device which includes a pull member cooperated with springs and a support is connected to the pull member such that the tension of the heating strap is kept at a certain level so that the area of cross section of the heating strap is maintained. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a heating strap assembly that comprises a frame composed of a first end board a second end board and two sides connected between the first and second end boards. Each of the two sides has a plurality of notches so that a plurality of supports are engaged with the notches. A recessed area is defined in an inner side of each side of the frame thereof and located close to the second end board. Each support each have a plurality of positioning recesses defined there such that a heating strap is engaged with the positioning recesses of the supports. Two positioning bars are connected between the first and second end boards so as to press the supports. 
   An adjusting device includes a U-shaped pull member connected to a driving support which includes two insertions movably engaged with the recessed areas of the two sides. The driving support includes positioning recesses with which the heating strap is engaged. The pulling member includes a transverse portion and two legs perpendicularly connected to two ends of the transverse portion. The two legs movably extend through the second end board and are connected with two nuts. Two springs are mounted to the two legs and biased between the second end board and the two nuts. 
   The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view to show the conventional heating assembly; 
       FIG. 2  is a top view to show the conventional heating assembly; 
       FIG. 3  is a perspective view to show the heating assembly of the present invention; 
       FIG. 4  is an exploded view to show the heating assembly of the present invention; 
       FIG. 5  is a side view to show the pull member connected to the driving support and are biased by two springs, and 
       FIG. 6  is a top view to show the heating assembly of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 2 to 6 , the heating assembly of the present invention comprises a rectangular frame  10  which is composed of a first end board  12 , a second end board  14  and two sides  16  which are connected between the first and second end boards  12 ,  14 . Each of the two sides  16  has a plurality of notches  162  defined in a top thereof and a recessed area  164  defined in an inner side thereof. The recessed areas  164  are located close to the second end board  14 . 
   A plurality of supports  20  are connected between the two sides  16  of the frame  10  by engaging two ends of each support  20  with the notches  162  in the two sides  16 . A plurality of positioning recesses  22  are defined in each support  20  and a separation portion  24  is located between adjacent positioning recesses  22 . Two positioning bars  30  are connected between the first and second end boards  12 ,  14  so as to press the supports  20 . Rivets  32  are used to fix the connection of the positioning bars  30  and the two sides  16 . 
   A heating strap  90  is engaged with the positioning recesses  22  of the supports  20  and the heating strap  90  generates heat when electric current goes through the heating strap  90 . 
   An adjusting device  40  includes a U-shaped pull member  42  which includes a transverse portion  422  and two legs  424  which are perpendicularly connected to two ends of the transverse portion  422 . The two legs  424  extend through a driving support  20 ′ which includes two insertions  26 ′ on two ends thereof and the two insertions  26 ′ are movably engaged with the recessed areas  164  of the two sides  16 . The driving support  20 ′ includes positioning recesses with which the heating strap  90  is engaged. The two legs  424  movably extend through the second end board  14  and are connected with two nuts  46 . Two springs  44  are mounted to the two legs  424  and biased between the second end board  14  and the two nuts  46 . The springs  44  normally pull the pull member  42  toward the second end board  14  and because the heating strap  90  is engaged with the positioning recesses of the driving support  20 ′, so that the driving support  20 ′ is movable within the recessed areas  164  of the two sides  16  to keep the tension of the heating strap  90 . 
   The heating strap  90  is pulled by the pull member  42  and keeps its tension so that the area of the cross section of the heating strap  90  is maintained within a range. In other words, even when the heating strap  90  inflates because of the heat, the area of the cross section is restricted and circuit short due to contact is avoided. Besides, the distance between the positioning recesses  22  of the supports  20  and the driving support  20 ′ can be made to be shorter than the distance of the positioning recesses of the conventional supports. This means that the length of the heating strap  90  is longer than that used for the conventional heating assembly. Lower temperature is needed to be produced from the same length of the heating strap  90  when compared with the heating strap of conventional heating assembly, this means the heating strap  90  of the present invention has longer term of life. 
   While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.