Patent Publication Number: US-7216566-B2

Title: Screwdriver-and-nut wrench-combined tuning tool for radio frequency filter

Description:
FIELD OF THE INVENTION 
   The present invention relates to a screwdriver-and-nut wrench-combined tuning tool for radio frequency filter; and more particularly, to a tuning tool for radio frequency filter which is capable of enabling a precise tuning and reducing a tuning time by preventing a tuning screw from turning when turning a tuning nut or the tuning nut from turning when turning the tuning screw by means of making a combined body of a screwdriver and a nut wrench used for the tuning of the radio frequency filter and locking them independently. 
   DESCRIPTION OF RELATED ART 
   A radio frequency filter is designed to minutely tune its output using a tuning screw and a tuning nut. The output signal varies depending on how deep the tuning screw is inserted into the inside of the radio frequency filter. When a performance of the radio frequency filter reaches to a desired level by the insertion of the tuning screw, it is locked on the radio frequency filter with the tuning nut and then epoxy is applied on a portion with which the tuning screw, the tuning nut and the filter meet for preventing unfastening of the tuning screw and the tuning nut by vibration. 
     FIG. 1   a  shows a tuning unit arranged in a line and  FIG. 1   b  shows a tuning unit arranged in a circle. The tuning screw  3  is locked by moving to the inside or outside of a filter  1  by its turning and then by turning the tuning nut  2  in the same direction as the tuning screw  3 . 
   In a conventional tuning method as shown in  FIG. 2 , an operator holds a screw driver  20  with a hand and holds a nut wrench handle  11  of a nut wrench  10  with the other hand; and then positions a tuning nut  2  in the inside of a nut locking unit  12 . At first, he or she turns and unfastens the tuning nut  2  with the nut wrench  10  by a certain amount. Then he or she moves the tuning screw  3  to the inside or outside of the filter  1  by means of turning the tuning screw  3  with the screw driver  20 . When a desired performance is attained, the tuning screw  3  is locked on the filter  1  by turning the tuning nut  2  with the nut wrench  10  keeping the screw  3  from turning with the screwdriver  20 . 
   In the conventional tuning method, however, there occurs a movement of the screwdriver  20  when turning the nut wrench  10  with a hand while holding the tuning screw  3  with the other hand to prevent the tuning screw  3  from moving from a desired position, thereby decreasing the tuning preciseness. 
   In addition, the tuning screws  3  are arranged at a narrow interval in case of a small sized filter and in a circle in case of a cylindrical filter; and thus, it is difficult for the screwdriver  20  accessing vertically and the nut wrench  10  accessing horizontally to access simultaneously to the tuning unit. 
   SUMMARY OF THE INVENTION 
   It is, therefore, an object of the present invention to provide a screwdriver-and-nut wrench-combined tuning tool for radio frequency filter which is capable of preventing a movement of a tuning screw occurred when locking it with a tuning nut by making their combined body, preventing a difficulty of tuning resulted due to a separate use of a screwdriver and a nut wrench when a space for access to a tuning unit is not sufficient, and minimizing an interruption of turns of the tuning screw and the tuning nut by locking or turning the screwdriver and the nut wrench independently. 
   In accordance with the present invention, there is provided a screwdriver-and-nut wrench-combined tuning tool for radio frequency filter comprising: a case; a nut wrench positioned to rotate inside the case and independently of the case for holding or turning a tuning nut; a screwdriver positioned to rotate inside the nut wrench independently of both the case and the nut wrench for holding or turning a tuning screw; a nut wrench locking unit that is fitted to the nut wrench or the case for locking the nut wrench; and a screwdriver locking unitthat is fitted to the case for locking the screwdriver. 
   The nut wrench includes a nut-turning unit for holding or turning the tuning nut by holding the outside of the tuning nut; and a turning handle positioned to be exposed onto the upper part of the case and connected to the nut-turning unit. And, the screwdriver includes a screw-turning unit positioned at the inside of the nut wrench and inserted into a groove formed at the tuning screw head for turning or locking the tuning screw. 
   The outside shape of the case may be of any shape but its inside shape is configured to be cylindrical so that the nut wrench can rotate and the screwdriver and a nut wrench locking unit can be installed thereon. 
   The nut wrench is provided with a transversal slot so that a screwdriver locking unit installed on the case is configured to pierce the nut wrench and then contact with the screwdriver, thus preventing the screwdriver locking unit from interrupting the turning of the nut wrench. 
   Other objectives and advantages of the invention will be understood by the following description and will also be appreciated by the embodiments of the invention more clearly. Further, the objectives and advantages of the invention will readily be seen that they can be realized by the means and its combination specified in the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and features of the instant invention will become apparent from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which: 
       FIGS. 1   a  and  1   b  are partial perspective views showing a tuning unit composed of a radio frequency filter, a tuning screw and a tuning nut; 
       FIG. 2  is a lateral view showing a method for tuning a radio frequency filter using a conventional screwdriver and a nut wrench; 
       FIG. 3  is a sectional view of a tuning tool for a radio frequency filter in accordance with a first embodiment of the present invention; 
       FIG. 4  is a sectional view of a tuning tool for a radio frequency filter in accordance with a second embodiment of the present invention; 
       FIG. 5  is a perspective view of a nut wrench in accordance with the present invention; and 
       FIG. 6  is a partial perspective view showing a contact portion of a locking unit in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The above-mentioned objectives, features, and advantages will be more apparent by the following detailed description in association with the accompanying drawings. Hereinafter, a preferred embodiment of the present invention will be set forth in detail with reference to  FIGS. 3 to 6 . 
     FIG. 3  is a sectional view of a tuning tool for a radio frequency filter in accordance with a first embodiment of the present invention and  FIG. 4  is a sectional view of a tuning tool for a radio frequency filter in accordance with a second embodiment of the present invention. And  FIG. 5  is a perspective view of a nut wrench in accordance with the present invention and  FIG. 6  is a partial perspective view showing a contact portion of a locking unit in accordance with the present invention. 
   As shown in  FIGS. 3 and 4 , the present invention comprises a case  100 , a nut wrench  200  positioned to rotate inside the case  100  independently of the case for holding or turning a tuning nut  2 , a screwdriver  300  positioned to rotate inside the nut wrench  200  independently of both the case and the nut wrench for locking or turning a tuning screw  3  and a nut wrench locking unit that is fitted to the nut wrench or the case for locking the nut wrench; and a screwdriver locking unitthat is fitted to the case for locking the screwdriver. 
   Specifically, the case  100  is configured to be shorter than the nut wrench  200  so that a tool with a minimum volume can reach the tuning screw  3  and the tuning nut  2 , thus enabling easier access thereto. 
   The nut wrench  200  is a portion that is installed to rotate inside the case  100  independently of the case  100 , and conducts the same function as a conventional nut wrench. 
   The nut wrench  200  includes a nut-turning unit  220  for turning the tuning nut  2  by holding the outside thereof and a turning handle  210  positioned to be exposed onto an upper part of the case  100  and connected to the nut-turning unit  220  for its turning. 
   The nut-turning unit  220  is formed to correspond to an outer shape of the tuning nut  2  to conduct the same function as a conventional nut locking unit so that the nut-turning unit  220  can unfasten the locked tuning screw  3  by turning the tuning nut  2  and lock the tuning nut  2  to prevent the tuning nut  2  from turning with the tuning screw  3  upon its tuning, and can be detached from the turning handle  210  to be replaceable depending on the size of the tuning nut  2 . 
   The turning handle  210  is exposed onto the outside of the case  100  so that an operator can adjust the tuning nut  2  by turning the nut-turning unit  220  or lock the tuning nut  2  with the nut-turning unit  220 . 
   The outside and inside surfaces of the nut wrench  200  are properly lubricated to enable smooth relative rotational movement with the case  100  and the screwdriver  300 . 
   The screwdriver  300  has a conventional screwdriver shape and can be formed with modified lengths and shapes of a handle when necessary. This screwdriver  300  is inserted to rotate inside the nut wrench  200  and can move up and down axially or be detached completely from the nut wrench  200  so that an operator can easily put the screwdriver  300  in a groove  4  of the tuning screw  3  after confirming an installation angle of the tuning screw  3  prior to inserting the screwdriver  300 . 
   The screwdriver  300  includes a screw-turning unit  320  inserted in the groove  4  formed at the tuning screw  3  for holding or turning the tuning screw  3  and a turning handle  310  positioned to be exposed onto the upper part of the nut wrench  200  and connected to the screw-turning unit  320  for its holding or turning. 
   The screw-turning unit  320  is inserted to rotate inside the nut wrench  200  and inserted into the groove  4  of the tuning screw  3  upon its tuning. With this structure, tuning is made by turning the tuning screw  3  after the tuning nut  2  is unfastened by the nut wrench  200  and change of a tuned position during a fastening operation of the tuning nut  2  after the tuning is completed is prevented. 
   The turning handle  310  is positioned to be exposed onto the upper part of the turning handle  210  of the nut wrench  200  so that an operator can adjust the tuning screw  3  by turning the screw-turning unit  320  or prevent change of a tuned position of the tuning screw  3  by locking the screw-turning unit  320 . 
   The locking unit  400  includes a nut wrench locking unit  410  for preventing turning of the nut wrench  200  and a screwdriver locking unit  420  positioned to pierce the case  100  and the nut wrench  200  for locking the screwdriver  300  by pressing one side thereof. 
   The nut wrench locking unit  410  is configured to pierce the turning handle  210  of the nut wrench  200  and contact with a surface of the case  100  or pierce the case  100  and contact the nut wrench  200  so as to lock the nut wrench  200 . 
   The screwdriver locking unit  420  is configured to pierce the case  100  and the nut wrench  200  sequentially and contact with the screwdriver  300  so as to lock the screwdriver  300 . 
   As shown in  FIG. 5 , the nut wrench  200  is provided with a penetration slot  230  to allow the screwdriver locking unit  420  to pierce, wherein the penetration slot  230  is formed with a predetermined length to prevent the screwdriver locking unit  420  from interrupting a turning of the nut wrench  200 . In this structure, the nut wrench  200  does not need a lot of turning because it is only for a fine tuning of filter. 
   In addition, each of the exposed portions of the nut wrench locking unit  410  and the screwdriver locking unit  420  has a suitable sized handle with a knurled surface to cause no slip and to put a sufficient torque therein. 
   Each of the nut wrench locking unit  410  and the screwdriver locking unit  420  may be provided with a contact portion made of a material with a high coefficient of friction at its edge part to be locked by contact with the nut wrench  200  and the screwdriver  300 . 
   Meanwhile, as shown in  FIG. 6 , the contact portion  430  is configured to correspond to the outside surfaces of the nut wrench  200  and the screwdriver  300  to secure a maximum contact area with the nut wrench  200  and the screwdriver  300 . 
   Now, a method for using the tuning tool of the present invention will be explained hereinafter. 
   First, it is assumed that an operator is a righthanded person. And then, the nut wrench  200  holds the tuning nut  2 , and the screwdriver  300  is inserted in the groove of the tuning screw  3  while inserting the screwdriver  300  in the nut wrench  200 ; and subsequently the tuning screw  3  and the tuning nut  2  are unfastened by turning the nut wrench  200  and the screwdriver  300  by a certain angle. Next, tuning is achieved by using the screwdriver  300  with the right hand while holding the case  100  with the left hand, and then the screwdriver  300  is locked by using the screwdriver locking unit  420  with the right hand. 
   Thereafter, the tuning screw  3  is locked by turning the tuning nut  2  while holding the turning handle  210  of the nut wrench  200  with the right hand. In addition, when needed, it is possible to fasten or unfasten the tuning screw  3  and the tuning nut  2  together under a state that the screwdriver  300  and the nut wrench  200  are locked. And also, it is possible to fasten or unfasten either of the tuning screw  3  and the tuning nut  2 , under a state of holing the screwdriver  300  and the nut wrench  200  with both hands, respectively. 
   The present invention as described early can enable a tuning operation in a small space by forming a screwdriver-and-nut wrench combined tuning tool and also enhance a tuning efficiency by preventing a tuning screw from turning when turning a tuning nut and a tuning nut from turning when turning a tuning screw by means of preventing mutual influence when turning a screwdriver or a nut wrench. 
   The present application contains subject matter related to Korean patent application No. 2005-76157, filed with the Korean Intellectual Property Office on Aug. 19, 2005, the entire contents of which are incorporated herein by reference. 
   While the present invention has been described with respect to the particular embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.