Abstract:
Provided is an internal switch-type salt meter in which an impact switching device operable by an impact applied into a main body is built in the main body so that it is unnecessary to separately waterproof the switching device. The salt meter includes a main body having the inside waterproofed against the outside, a sensor part disposed on an end of a side of the main body to detect salinity of an object to be measured, a display part disposed on a surface of a side of the main body to display a result measured by the sensor part, and a switching device built in the main body to generate a contact point by an impact with an external impact object, thereby operating the sensor part and the display part. The switching device may be built in the main body so that a separate waterproof process is not required.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Korean Patent Applications KR 10-2012-0013932 with a filing date of Feb. 10, 2012 and KR 10-2013-0000958 with a filing date of Jan. 4, 2013. Furthermore, aforementioned Korean Patent Applications KR 10-2012-0013932 and KR 10-2013-0000958 are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a salt meter, and more particularly, to an internal switch-type salt meter in which an impact switching device operable by an impact applied into a main body is built in the main body so that it is unnecessary to separately waterproof the switching device. 
     BACKGROUND OF THE INVENTION 
     In general, salt meters measure salinity by using a property in which electrical conductivity is changed according to an ion concentration of sodium chloride (NaCl) contained in foods. That is, a pair of electrodes may contact an object to be measured (hereinafter, referred to as a measurement object), and then a voltage may be applied into the pair of electrodes to measure an amount of flowing current, thereby obtaining salinity of the corresponding object. 
     To measure salinity, a power button may be pushed in a state where a salt meter is put inside a cooking container to contact a food, or a measurement button may be pushed when the power button is turned on to measure the salinity of the food. That is, the salt meter should be immersed into a measurement object for a predetermined time, and also, a separate switch should be manipulated to measure the salinity. In addition, since a switch that is necessarily provided for manipulating is an electrical device, the switch must be waterproofed. 
     For this, a salt meter  10 , as shown in  FIG. 1 , includes a measurement part  12 , a display part  13 , and a manipulation part  14  on a main body  11  defining an outer appearance thereof. The manipulation part  14  according to the related art includes a button type switch  15  which is generally exposed to the outside and is manipulated through a push or touch operation. The switch  15  is mounted on a board  16  on which a predetermined circuit is printed. The switch  15  has one side passing through a hole and exposed to the outside of the main body  11 . Also, a waterproof film  17  surrounds the switch  11  together with the main body  11 . Thus, the salt meter may measure salinity or temperature within the measurement object. 
     The switch operable by the push or touch operation as described above may be easily manipulated. However, as the switch is incalculably and repeatedly touched to wear the waterproof film  17 . As a result, the switch is used for a long time to make a hole in the waterproof film, thereby losing the waterproof function. Also, when a measurement apparatus is manufactured, a process of attaching the separate waterproof film  17  for protecting the switch  15  should be performed. Thus, the manufacturing process may be complicated, and also, manufacturing costs may be increased. Also, to apply a switching device into the measurement apparatus being gradually miniaturized, the switching device should be gradually miniaturized. Thus, the push or touch operation by a user may be trouble to limit the miniaturization. 
     To solve the above-described limitations, a salt or temperature measurement apparatus which is operated by using electrical conductivity without a separate touch operation by the user is being proposed. However, since a basic power source should be continuously supplied into the measurement apparatus using the electrical conductivity to detect a flow of current between electrodes, it may be very disadvantageous in power consumption. 
     Currently, vibration detection apparatuses using elasticity are proposed with the purpose of earthquake sensing or security. However, such a vibration detection apparatus may detect only simple vibration and also not be used as a switching device for ON/OFF operation. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to an automatic salt meter having internal switching device 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 temperature or salinity measurement apparatus in which a switching device is built in a main body so that a separate waterproof process is not required for the switching device to simplify a manufacturing process and reduce manufacturing costs. 
     Another object of the present invention is to provide a temperature or salinity measurement apparatus in which a separate power is not required for a switching operation to reduce power consumption, and which is operated by only an impact to prevent the measurement apparatus from malfunctioning by external vibration. 
     According to an aspect of the present invention, there is provided a salt meter including: a main body having the inside waterproofed against the outside; a sensor part disposed on an end of a side of the main body to detect salinity of an object to be measured; a display part disposed on a surface of a side of the main body to display a result measured by the sensor part; and a switching device built in the main body to generate a contact point by an impact with an external impact object, thereby operating the sensor part and the display part. 
     The switching device may include: a hollow housing; a coil extending inward from a side of the housing; and a support member supporting a side of the coil at a side of the housing, wherein an end of the coil electrically contacts the housing by elasticity of the coil due to the impact with the external impact object to cause a switching operation. 
     The housing may be formed of a conductive metal material. The housing may be partitioned into a plurality of regions in which the end of the coil electrically contacts the housing by an insulation member. 
     The switching device may further include a guide protrusion disposed on an inner wall between the plurality of partitioned regions of the housing. 
     The switching device may include: a hollow housing; a frame having a length greater than a diameter of the housing, the frame being coupled to the housing while being bent to cross an inner space of the housing; and a support member supporting both ends of the frame on both sides of the housing, wherein a central portion of the frame is changed in position according to an impact with an external impact object to electrically contact the housing, thereby causing a switching operation. 
     The housing may be electrically partitioned into both sides with respect to the frame by the insulation member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a salt meter according to a related art. 
         FIG. 2  is a perspective view of a salt meter according to an embodiment of the present invention. 
         FIG. 3  is a cross-sectional view illustrating a schematic structure of a switching device according to an embodiment of the present invention. 
         FIG. 4  is a cross-sectional view illustrating various switching operations in the switching device of  FIG. 3 . 
         FIG. 5  is a cross-sectional view illustrating a modified example of the switching device of  FIG. 3 . 
         FIG. 6  is a cross-sectional view illustrating a switching operation in a switching device according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Technical objectives of the present invention will become evident through the following embodiments. Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. 
       FIG. 2  is a perspective view of a salt meter according to an embodiment of the present invention. Referring to  FIG. 2 , a salt meter  100  according to an embodiment of the present invention includes a main body  110  defining an outer appearance thereof, a measurement part  120  disposed on a side of the main body  110 , a display part  130  disposed on a surface of a side of the main body  110 , and a manipulation part  140  disposed within the main body  110 . 
     Here, the main body  110  may be provided as an injection-molded container having a hollow therein and formed of a plastic material. Also, the main body  110  may have a bar shape on the whole to allow a user to easily grasp the salt meter  100 . The main body  110  includes the measurement part  120 , the display part  130 , and the manipulation part  140 . The salt meter  100  is typically used in a state where the salt meter  100  is immersed into a measurement object such as foods. Thus, the main body  110  may have structure with the inside and outside sealed. 
     The measurement part  120  is configured to measure salinity or temperature of the measurement object. The measurement part  120  is disposed on one end of the main body  110 . The measurement part  120  typically includes a salinity detection sensor  121  for measuring salinity that is a concentration of NaCl contained in the measurement object. In recent, the measurement part  120  includes a temperature detection sensor  122  for measuring a temperature of the measurement object in addition to the salinity of the measurement object. The salinity detection sensor  121  includes a pair of sensor pins formed of plated bronze. The salinity detection sensor  121  measures the salinity by using a potential difference generated in each of the sensor pins. 
     The display part  130  displays an operation state of the salt meter  100  and the salinity and temperature detected by the measurement part  120 . 
     The manipulation part  140  is a switching device for manipulating an operation of the salt meter  100  such as an ON/OFF operation of the salt meter  100  or a measurement mode change of the salinity and temperature. As shown in  FIG. 2 , the manipulation part  140  is disposed within the main body  110 . The manipulation part  140  is mounted on a typical board  141 . Also, the manipulation part  140  is electrically connected to a circuit printed on the board  141  to transmit a switching signal into a control part (not shown) built in an IC chip shape. Here, the main body  110  may be sealed again the outside and completely waterproofed to prevent internal parts from electrically malfunctioning. Particularly, the manipulation part  140  according to an embodiment of the present invention may be switched in a state where the manipulation part  140  is disconnected to the outside. That is, the manipulation part  140  may be switched by an impact of the main body itself, but not by an external push or touch operation. Hereinafter, the manipulation part  140  will be described in detail. 
       FIG. 3  is a cross-sectional view illustrating a schematic structure of a switching device according to an embodiment of the present invention. A switching device  150  according to an embodiment of the present invention includes an impact switch using elasticity of a coil. 
     In detail, the switching device  150  includes a housing  151 , an elastic coil  152  disposed within the housing  151 , a support member  153  supporting the elastic coil  152  within the housing  151 , and a wire  154  connected to each of sides of the housing  151  and the elastic coil  152 . 
     Here, the housing  151  defines an outer appearance of the switching device  150 . The housing  151  has a hollow circular shape or a polygonal cylindrical shape. The hollow housing  151  receives the coil  152  and the support member  153  therein. The housing  151  may be formed of an electrical nonconductor such as plastic for insulating. In this case, a separate electrode should be provided. According to the present invention, the housing  151  is formed of an electrical conductor so that the housing itself serves as an electrode. For example, the housing  151  according to the present invention may be formed of bronze. 
     The coil  152  has an end which is changed in position by an impact. Thus, the coil  152  may be configured to perform a switching operation. The coil  152  has one end fixed to the housing  151  by the support member  153  and the other end disposed in an inner space of the housing  151 . Here, the other end of the coil  152  is disposed at a central portion with respect to an inner wall of the housing  151 . Particularly, the coil  152  according to the present invention may include coil having an elastic modulus and sufficient hardness which is not deformed by external vibration. The coil  152  may be formed of an electrical conductor such as phosphor bronze to apply an electrical signal. 
     The support member  153  supports one end of the coil  152  on a side of the housing  151 . The support member  153  may be formed of plastic that is an electrical nonconductor or an injection-molded resin material to electrically insulate the housing  151  from the coil  152 . 
     The switching device  150  is built in the main body  110  of the salt meter  100  to perform a switching operation even as the salt meter  100  is impacted into an external impact object. 
       FIG. 4  is a cross-sectional view illustrating various switching operations in the switching device of  FIG. 3 .  FIG. 5  is a cross-sectional view illustrating a modified example of the switching device of  FIG. 3 .  FIGS. 4 and 5  illustrate cross-sections in an A-A direction, respectively. 
     A switching operation of the switching device  150  according to an embodiment of the present invention will be described with reference to  FIG. 4 . Referring to  FIG. 4A , when the switching device  150  is impacted onto an impact object  200  while being moved in a left direction, an end of the coil  152  may be instantaneously changed in position in a direction of the impact object  200  by impact inertia to return to its original position. Here, the end of the coil  152  and a left inner wall of the housing  151  may instantaneously contact each other to cause a switching operation. Similarly, referring to  FIG. 4B , when the switching device  150  is impacted onto an impact object  200  while being moved in a right direction, an end of the coil  152  may be instantaneously changed in position in a direction of the impact object  200  by impact inertia to return to its original position. Here, the end of the coil  152  and a right inner wall of the housing  151  may instantaneously contact each other to cause a switching operation. Due to the instantaneous position change of the coil  152 , the housing  151  and the coil  152  may contact each other to cause an electrical switching operation. 
     Here, the coil  152  may have an elastic modulus with sufficient intensity which is not shaken by external vibration. In general, the impact inertia may have greater by about 5 times to about 7 times than vibration inertia. Also, an impact amount may be proportional to the product of an acting force and a time. Thus, even though the coil  152  is designed so that the coil  152  is not shaken by the external vibration, since a strong inertial force instantaneously occurs by the impact, the end of the coil  152  may be sufficiently changed in position by the inertia. Also, although the switching device  150  is directly impacted onto the impact object  200  in the description of the switching operation, since the switching device  150  is disposed within the main body of the salt meter  100 , the salt meter  100  is impacted onto the impact object  200  to cause the same switching operation. Also, a user&#39;s hand may be used as the impact object  200 . 
     Referring to  FIG. 5 , in the switching device  150  according to an embodiment of the present invention, the housing  151  is partitioned into a plurality of regions. Also, a guide protrusion  156  may be further disposed on the inner wall of the housing  151 . 
     According to the present invention, the housing  151  may be formed of bronze so that the housing itself  151  serves as the electrode. Here, the housing (the electrode)  151  may be partitioned into two regions as shown in  FIG. 5A  or four regions as shown in  FIG. 5B  by the insulation member  155 . When the housing  151  is integrally manufactured, the switching device  150  may perform only an ON/OFF operation. However, when the housing  151  is partitioned in the two regions as shown in  FIG. 5A , the two regions may be classified into control signals such as an “increase (+)” and a “decrease (−)”. Also, when the housing  151  is partitioned into the four regions as shown in  FIG. 5B , the four regions may be classified into various control signals such as an “increase (+), a “decrease (−)”, a “left movement”, and a ‘right movement”. The number of regions of the housing  151  partitioned into a plurality of regions may be variously set according to the purpose of use. Here, the wire  154  may be connected to the coil  152  and an end of a side of each housing  151  and thus be electrically connected to the board  141 . Also, the wire  154  may be connected to a control part and a power source part through the circuit printed on the board  141 . 
     Also, the guide protrusion  156  may be disposed inside the insulation member  155 , i.e., on an inner wall between the plurality of regions of the housing  151 . Thus, even if the switching device  150  is exactingly impacted in a specific direction, the end of the coil  152  may be impacted onto a specific region of the housing  151 . That is, since it is difficult to impact the switching device, i.e., the salt meter  100  in an accurate direction, even if the impact direction is somewhat out of a target position, the end of the coil  152  may be guided into the regions of the housing  151  by the guide protrusion  156  in a direction to be impacted. The guide protrusion  156  may have a spherical or aspheric shape and be formed of an insulation material. 
       FIG. 6  is a cross-sectional view illustrating a switching operation in a switching device according to another embodiment of the present invention. A switching device  150  according to another embodiment of the present invention includes an impact switch using elasticity of a frame  151 . 
     Referring to  FIG. 6 , the switching device  150  according to another embodiment of the present invention includes a housing  151  and a frame  157  coupled to the housing  151  while crossing an inner space of the housing  151 . The housing  151  may be formed of bronze to serve as an electrode. The frame  157  may be fixed to the inside of the housing  151  by an insulation member  155  to insulate the housing  151  from the frame  157 . The insulation member  155  may support the frame  157 , and also partition the inside of the housing  151  into both regions with respect to the frame  157  so that the housing  151  includes two electrodes. 
     In the switching device  151  according to another embodiment of the present invention, the housing  151  may have a rectangular shape in section. Also, the frame  157  having a predetermined width and thickness may bisectionally cross the inner space of the housing  151  along a long direction of the housing  151 . Here, the frame  157  may have a length greater than that in the long direction of the inner space of the housing  151 . Also, the frame  157  may be bent as shown in  FIG. 6 . Here, a central portion of the bent frame  157  may contact an inner wall of the housing  151  in a short direction of the inner space. 
     Referring to the switching operation of the switching device  150  according to another embodiment of the present invention, as shown in  FIG. 6A , when the switching device  150  is impacted into an impact object  200  while being moved in a left direction, the central portion of the frame  157  may be changed in contact position on a left inner wall of the housing  151  in a direction of the impact object  200  by impact inertia. Also, in this state, as shown in  FIG. 6B , when the switching device  150  is impacted onto the impact object  200  while being moved in a right direction, the central portion of the frame  157  may be changed in contact position on a right inner wall of the housing  151 . When the above-described processes are repeatedly performed, the frame  157  may perform the switching operation with respect to a left electrode  154  and a right electrode  154 . 
     As described above, the manipulation part according to the embodiments of the present invention may perform the switching operation by simply impacting the main body of the salt meter onto the object such as a palm. Also, the salt meter may be turned on or off through the sample impact operation to reduce power consumption. Also, although the switching device using the impact is applied into the salt meter in the description of the present invention, the switching device may be applied into various measurement devices such as a thermometer in addition to the salt meter. That is, the salt meter according to the present invention may include various measurement devices such as the thermometer. 
     According to the present invention, the switching device may be built in the main body so that a separate waterproof process is not required for the switching device to simplify the manufacturing process and reduce the manufacturing costs. 
     Also, according to the present invention, a separate power may not be required for the switching operation to reduce power consumption, and the salt meter may be operated by only the impact to prevent the salt meter from malfunctioning by the external vibration. 
     Also, the ON/OFF operation due to the impact may be applied into the switching device using the impact. 
     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.