Patent Publication Number: US-6906301-B2

Title: Mounting structures for a high-frequency heating apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a high-frequency heating apparatus capable of rationalizing magnetron-attaching work in a manufacturing process of a high-frequency heating apparatus so that a high-speed manufacturing line of the high-frequency heating apparatus is made possible, and capable of readily performing magnetron-exchanging work at an end user&#39;s home, so that a repairing time is reduced and improvement of service to customers can be performed. 
     2. Description of the Related Art 
     In order to prevent leakage of high-frequency waves from a joint between a magnetron and a magnetron holding plate or a joint between a magnetron and a waveguide, in a high-frequency heating apparatus, the magnetron is attached onto the magnetron holding plate with three or four screws so that the magnetron can stand against vibration and shock produced at the goods conveying time. 
     A general high-frequency heating apparatus is shown in FIG.  6 . 
     In  FIG. 6 , reference numeral  1  indicates a magnetron,  2  indicates a magnetron holding plate,  3  indicates a waveguide,  4  indicates a heating chamber wall, and  5  indicates a screw. The waveguide  3  and the magnetron holding plate  2 , and the waveguide  3  and the heating chamber wall  4  are joined by welding or caulking. An antenna la of the magnetron  1  is inserted into a hole  3   a  of the waveguide  3  horizontally and thereafter four or three screws  5  are tighten to attach the magnetron  1 . 
     However, under the above apparatus, in a manufacturing process of the high-frequency heating apparatus, it is necessary for a worker attaching the magnetron  1  to continuously perform the steps of inserting the antenna  1   a  of the magnetron  1  into the hole  3   a  of the waveguide  3  horizontally and attaching the magnetron  1  with four or three screws  5  while holding the magnetron  1  so that the magnetron  1  does not slip from the magnetron holding plate  2 . This work must be performed by one worker in order to prevent positional slippage of the magnetron  1  and to prevent the slippage between the magnetron  1  and screw holes of the magnetron holding plate  2  when the screws  5  are tightened, so that its work cannot correspond to rationalization and speed-up of a manufacturing process. Further, the work of inserting the antenna  1   a  of the magnetron  1  into the hole  3   a  of the waveguide  3  horizontally requires concentration power of the worker. Further, if the worker erroneously hits the antenna  1   a  of the magnetron  1  on the surroundings of the hole  3   a  of the waveguide  3  when he inserts it, oscillation frequency of the magnetron  1  varies, so that the magnetron  1  becomes bad. 
     When the apparatus breaks down, a service man visits a home of a customer who is an end user to repair the apparatus. However, the number of customers who have limited at-home time such as a worker in double harness and a worker apart from his family is recently increasing. Therefore, though the repair at customer&#39;s home requires the short repairing time, the exchange or repair of the magnetron cannot be performed in the short time. 
     SUMMARY OF THE INVENTION 
     In order to solve the above problems, an object of the invention is to provide a high-frequency heating apparatus which rationalizes an attachment method of a magnetron, performs speed-up of a manufacturing process and reduction of repair and exchange time of the magnetron, and realizes error reduction of the magnetron in the manufacturing process. 
     According to the first aspect of the invention, a high-frequency heating apparatus of the invention includes a high-frequency generating unit, a heating chamber into which food is stored, a waveguide that guides high-frequency waves generating from the high-frequency generating unit to the heating chamber, and a holding plate for fixing the high-frequency generating unit to the waveguide, and further is so constituted that the high-frequency generating unit is attached to the holding plate with at most two screws. Hereby, attachment of the high-frequency generating unit is facilitated, speed-up of the manufacturing process of the high-frequency heating apparatus can be realized, and production efficiency can be improved. Further, in the breakdown repair, working time can be also reduced, so that service can be improved. 
     According to the second aspect of the invention, one side of attachment flanges of the high-frequency generating unit according to the first aspect is inserted into holes provided for the holding plate, and the other side thereof is attached to the holding plate with the at most two screws. Hereby, the relative position between the screws becomes close, and operation of work necessary to tighten the screws becomes small. Therefore, the time is reduced and simultaneously physical load on the worker can be reduced. Further, since the attachment flanges of the high-frequency generating unit are inserted to and held by the holding plate, the high-frequency generating unit can be fixed to the holding plate more strongly than a case where the high-frequency generating unit is attached to the holding plate with four screws. Therefore, there can be allowances of strength in relation to vibration and shock produced at the goods conveying time. In result, packing material including foaming polystyrol and corrugated cardboards can be miniaturized or thinned, and saving of resources and cost-reduction can be attempted. 
     According to the third aspect of the invention, a rotary guide is provided for the holding plate according to the second aspect. When the high-frequency generating unit is turned about the attachment flanges of the high-frequency generating unit inserted into the holding plate along the rotary guide, the high-frequency generating unit can be positioned to the holding plate with a regular locus. Hereby, without fear that the antenna is damaged erroneously, the high-frequency generating unit can be attached, and error reduction of the high-frequency generating unit and stabilization of quality of the high-frequency heating apparatus can be realized. Further, since there is no fear that the antenna is damaged, the speed of the work of positioning the high-frequency generating unit is improved, and the speed-up of the manufacturing process can be realized. 
     According to the fourth aspect of the invention, claws for holding the high-frequency generating unit are provided in the vicinity of the holes of the holding plate into which the attachment flanges of the high-frequency generating unit are inserted, whereby even if a worker releases his hold of the high-frequency generating unit before tightening the screw during the attachment work of the high-frequency generating unit, the high-frequency generating unit does not fall down but is held. Therefore, the worker can perform the screw tightening work with his both hands, so that it is possible to reduce the time necessary to attach the high-frequency generating unit. Further, since the high-frequency generating unit does not fall down if the screw is not tightened, the attachment work of the high-frequency generating unit may be performed by a worker who positions the high-frequency generating unit to the holding plate and a worker who performs the screw-tightening work. Hereby, since the amount of work per person can be reduced, speed-up of the manufacturing process can be realized. 
     According to the fifth aspect of the invention, the holding plate according to the second aspect has a drawn portion larger than the area of the attachment flanges of the high-frequency generating unit inserted into the holding plate, and the depth of the drawn portion is smaller than the thickness of the inserted attachment flange of the high-frequency generating unit. Hereby, a joint between the high-frequency generating unit and the holding plate or a joint between the high-frequency generating unit and the waveguide becomes strong, and leakage of high-frequency waves from the joint can be prevented equivalently to or more than the case of the attachment of the related art by only screw tightening. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an assembly diagram for magnetron attachment in a first embodiment of the invention; 
         FIG. 2  is a perspective view of the magnetron in the first embodiment of the invention; 
         FIG. 3  is a perspective view of a magnetron holding plate in a second embodiment of the invention; 
         FIG. 4  is a locus diagram of a magnetron attaching operation in the second embodiment of the invention; 
         FIG. 5  is a perspective sectional view of a magnetron holding plate in a third embodiment of the invention; and 
         FIG. 6  is an assembly diagram for magnetron attachment in a general high-frequency heating apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments of the invention will be described below with reference to drawings. 
     (Embodiment 1) 
       FIG. 1  is an assembly diagram for attaching a high-frequency generating unit of a high-frequency heating apparatus in a first embodiment of the invention. 
     In  FIG. 1 , reference numeral  4  indicates a heating chamber wall onto which a waveguide  3  indicates attached by welding or caulking, and further a magnetron holding plate  2  indicates attached to the waveguide  3  similarly by welding or caulking. For the magnetron holding plate  2 , holes  2   a  for inserting attachment flanges  1   b  of the magnetron  1  provided as a high-frequency generating unit are provided. 
     Regarding the thus constituted magnetron holding plate, its operation and working will be described below. 
     Firstly, the attachment flanges  1   b  of the magnetron  1  are inserted into the holes  2  of the magnetron holding plate  2 , and the magnetron  1  is turned up and down about the inserted attachment flanges  1   b  to insert an antenna  1   a  of the magnetron  1  into a hole  3   a  of the waveguide  3 . Thereafter, two screws  5  are tightened to the flanges on the opposite side to the inserted attachment flanges  1   b  of the magnetron  1 . 
     As described above, in this embodiment, the number of the screws  5  used for attaching the magnetron  1  is reduced from the conventional three or four screws to two screws, whereby the working time necessary to attach the magnetron  1  is reduced, physical load onto a worker can be reduced by speed-up of a manufacturing process and reduction of the working amount, and service to customers can be improved by reduction of the magnetron exchanging time in the breakdown repair. 
     Further, in the embodiment, two holes  2   a  are provided for the magnetron holding plate  2 . Since the attachment flanges  1   b  of the magnetron  1  are inserted to their holes  2   a , the magnetron can be fixed to the magnetron holding plate more strongly than a case where the magnetron is attached to the magnetron holding plate with four screws. Therefore, there can be allowances of strength in relation to vibration and shock. In result, packing material including foaming polystyrol and corrugated cardboards can be miniaturized or thinned, and saving of resources and cost-reduction can be attempted. 
     Further, positions at which the screws  5  are tightened may be sides of the attachment flanges  1   b  of the magnetron  1  adjoining to each other one by one as shown in  FIG. 2 , not on the opposite side to the inserted side of the attachment flanges  1   b  of the magnetron  1  as shown in FIG.  1 . In this case, the similar effect to that in the foregoing can be obtained. 
     (Embodiment 2) 
       FIG. 3  is a perspective view of a magnetron holding plate  2  in a second embodiment of the invention, and this embodiment is different from the first embodiment in that a rotary guide  2   b  is provided for the magnetron holding plate  2 . Since the same reference numerals as those in the first embodiment have the same structure, their explanation are omitted. 
     Firstly, attachment flanges  1   b  of a magnetron  1  are inserted into holes  2   a  of the magnetron holding plate  2 . Thereafter, when the magnetron  1  is pushed against the rotary guide  2   b  and turned along the shape of the rotary guide  2   b , it is positioned to the magnetron holding plate  2  with a regular locus. 
     As described above, in the embodiment, since the rotary guide  2   b  is provided for the magnetron holding plate  2 , the magnetron  1  draws a regular locus as shown in  FIG. 4  when it is attached. Therefore, without fear that an antenna la of the magnetron  1  is erroneously hit against the waveguide  3  and damaged, error reduction of the magnetron and stabilization of quality of the high-frequency heating apparatus can be realized. Further, in  FIG. 3  showing this embodiment, the number of the rotary guide  2   b  is one. However, even if plural guides are provided, the similar effect can be obtained. 
     (Embodiment 3) 
       FIG. 5  shows a perspective sectional view of a magnetron holding plate  2  in a third embodiment of the invention. 
     In  FIG. 5 , this embodiment is different from the first embodiment in that claws  2   d  holding a magnetron  1  are provided for upper sides of holes  2   a  of the magnetron holding plate  2 . Since the same reference numerals as those in the first embodiment have the same structure, their explanation are omitted. 
     Firstly, attachment flanges  1   b  of the magnetron  1  are inserted into the holes  2   a  of the magnetron holding plate  2 . For the attachment flanges  1   b  of the magnetron  1 , holes  1   c  such as screw holes used for tightening screws in the conventional constitution are provided. Their holes  1   c  are passed through the claws  2   d  of the magnetron holding plate  2 , whereby even if a worker releases his hold of the magnetron  1  before tightening the screws  5  during the magnetron attachment work, the magnetron  1  does not fall down but is held. Therefore, the worker can perform the screw tightening work with his both hands, so that it is possible to reduce the time necessary to attach the magnetron  1 . Further, since the magnetron  1  does not fall down even if the crew is not tightened, the magnetron attachment work may be performed by a worker who positions the magnetron  1  to the magnetron holding plate  2  and a worker who performs the screw tightening work. Hereby, since the amount of work per person can be reduced, speed-up of the manufacturing process can be realized. 
     Further, in this embodiment, there is provided a drawn portion  2   c  larger than the area of the attachment flanges  1   b  of the magnetron  1  inserted into the magnetron holding plate  2 , and the depth of the drawn portion  2   c  is smaller than the thickness of the inserted attachment flange  1   b  of the magnetron  1 . Hereby, a joint between the magnetron  1  and the magnetron holding plate  2  or a joint between the magnetron  1  and the waveguide  3  becomes strong, and leakage of high-frequency waves from the joint can be prevented equivalently to or more than the case of the conventional magnetron attachment by only screw tightening. 
     As described above, according to the invention, by rationalizing the attachment method of the magnetron, speed-up of the manufacturing process and reduction of repair and exchange time of the magnetron can be performed, and further error reduction of the magnetron in the manufacturing process can be realized.