You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority of Korean Patent Application Number 10-2012-0098188 filed Sep. 5, 2012, the entire contents of which application is incorporated herein for all purposes by this reference. 
       BACKGROUND OF INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a two step link hood latch apparatus for vehicle, which opens a hood only with indoor manipulation. 
         [0004]    2. Description of Related Art 
         [0005]    Vehicles have been recognized and developed as a mere transportation means or conveying equipments. However, due to the diverse consumer preferences, technological competition among vehicle manufacturers has been intensified to meet the various requirements. 
         [0006]    Recently, vehicles have been evolving by putting more emphasis on the conveniences and services of a vehicle than on its appearance and design by developing control and convenience devices to provide more convenience for drivers. 
         [0007]    A two step link hood latch apparatus has been developed to have more superior product competitiveness than other companies&#39; products in the world market as well as the domestic market. 
         [0008]    In general, since a hood has a two step locking structure using a safety hood, when a release lever is operated inside a vehicle in order to release a locked hood, a first step restraint is released with a cable operation, and then, a second step safety device for hood operation is prepared in order to open the hood with a safety lever&#39;s release after a user puts the hand in an engine room, standing in front of the vehicle. 
         [0009]    This is provided for satisfying vehicle safety standard regulations. Accordingly, a firm hood latch apparatus needs to be installed at the hood of a vehicle, and also, the vehicle with a hood structure, in which the hood is opened/closed at the front direction and interferes with driver&#39;s visibility when the hood is opened during driving, is regulated with a two step locking or two spot locking structure. 
         [0010]      FIG. 1  is an operational state view of a method of releasing a typical hood latch device. As shown in the first drawing, a hood striker  5  is double-locked by a claw  1  and a hook  2  in the initial state. 
         [0011]    Then, as shown in the second drawing, when a driver operates a release lever disposed at the indoor driver&#39;s seat, a pawl  4  is pulled out in the arrow direction (→) of  FIG. 1B  and rotates, so that the restraint force applied to the claw  1  is released. 
         [0012]    Then, as shown in the third drawing, as the claw  1  rotates, the striker  5  comes out from an insertion groove  1   a  of the claw  1  and thus the hood is slightly raised because a first lock state changes into a first open state. 
         [0013]    Then, as shown in the drawing, when a driver steps out of a vehicle and then puts the hand inside the first opened hood and pushes the safety lever  3  toward the arrow direction of  FIG. 1D , the hook  2  connected to the safety lever  3  rotates and the restraint force that holds the hood striker  5  is released, so that the hood changes from a secondary lock state into a secondary open state. 
         [0014]    However, when a driver tries to open the hood, it is cumbersome and inconvenient for the driver to operate the release lever inside the vehicle in order to release the first lock, and then, step out of the vehicle in order to put the hand inside the hood and operate the safety lever  3 . 
         [0015]    Moreover, when a driver operates the release lever, the motion of the pawl  4  is directly passed to the driver through a cable, so that operability becomes poor. 
         [0016]    The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       SUMMARY OF INVENTION 
       [0017]    The present invention provides a two step link hood latch apparatus for vehicle, in which a first stop end and a second stop end of a claw are configured to be stopped by a stop protrusion of a pawl, operability (i.e., pulling force) occurring at a release handle is passed from wire to the pawl through a pivot and link, the stroke of the link is adjusted through a “U” shaped first and second step slots formed at the pawl, and the rotation of the claw is adjusted in two steps through a two step operation of the release handle. Accordingly, the hood is opened only with indoor manipulation, a predetermined operability is implemented, and inconveniently putting the hand in an engine room to open an existing hood is improved. 
         [0018]    Various aspects of the present invention provide for a two step link hood latch apparatus for a vehicle, which allows a hood to be opened only with an operation of a release handle inside a vehicle, the apparatus including: a claw disposed at a base plate to be rotatable, restraining a hood striker through a stop groove, and restrained to a pawl through first and second stop ends in first step and second step lock states; the pawl disposed at the base plate to be rotatable and restraining the rotation of the claw in steps by using the stop protrusion; a pivot disposed at the base plate to be rotatable in a hinge structure and transmitting a pulling force generated from the release handle; and a link connecting the pivot and the pawl and rotating the pawl in linkage with the pivot. 
         [0019]    The pawl may be connected to the link by using an operation axis as a medium, and may include first step and second stop slots formed being vertically spaced a predetermined distance apart from each other for the connection of the operation axis and a connection slot connecting the first step and second step slots; and when the hood changes from a first step lock state into a second step lock state or from a first step open state to a second step open state, the operation axis may move from the first step slot to the second step slot or from the second step slot to the first step slot, through the connection slot. 
         [0020]    The pawl may include a first step slot and a second step slot at the connection part with the link. The rotation of the pawl may be adjusted by adjusting the stroke of the link through the lengths of the first step and second step slots. 
         [0021]    The link may be connected to the pivot by using a third rotation axis as a medium, and may convert the rotary motion of the pivot into the horizontal linear motion to operate the pawl. 
         [0022]    The link may have a link groove formed concavely on the upper surface with a smooth curvature. The claw may have a circular link restraint member. The link restraint member may contact the link groove to restrain the link. 
         [0023]    The link may have a third spring disposed at the connection part with the pivot, and may move the operation axis of the link from the first step slot to the second step slot by using the third spring. 
         [0024]    The present methods and apparatuses have other features and advantages apparent from the accompanying drawings, incorporated herein, and below Detailed Description, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a view illustrating a method of releasing a typical hood latch device. 
           [0026]      FIG. 2  is a view illustrating a configuration of an exemplary two step link hood latch apparatus according to the present invention. 
           [0027]      FIG. 3  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0028]      FIG. 4  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0029]      FIG. 5  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0030]      FIG. 6  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0031]      FIG. 7  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0032]      FIG. 8  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0033]      FIG. 9  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0034]      FIG. 10  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0035]      FIG. 11  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0036]      FIG. 12  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0037]      FIG. 13  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0038]      FIG. 14  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0039]      FIG. 15  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
           [0040]      FIG. 16  is a view illustrating an operational state of an exemplary two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
       
    
    
       [0041]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. Certain design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0042]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawings. 
       DETAILED DESCRIPTION 
       [0043]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0044]    It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
         [0045]      FIG. 2  is a view illustrating a configuration of a two step link hood latch apparatus according to various embodiments of the present invention. 
         [0046]    The present invention relates to a two step link hood latch apparatus, which performs a two step locking function on a hood latch itself so as to improve marketability. 
         [0047]    The two step link hood latch apparatus may operate a release handle twice inside a vehicle so as to open the hood in two steps, so that when a driver opens the hood, cumbersomeness in operating a safety lever outside the vehicle may be improved. 
         [0048]    For this, the two step link hood latch apparatus according to various embodiments of the present invention may include a base plate  10 , a pawl  16 , a claw  13 , a link  20 , and a pivot  19 . 
         [0049]    The base plate  10  may be vertically installed at the body front part, and an insertion groove  11  may be formed directly below the upper center of the base plate  10 . When the hood is closed, a hood striker  12  may be inserted into the insertion groove  11 , and when the hood is opened, the hood striker  12  may come out from the insertion groove  11 . 
         [0050]    The claw  13  may be hinge-coupled to a first rotation axis  14  installed at the right side of the base plate  10  and thus may be mounted on the base plate  10  to be rotatable. The claw  13  may be elastically supported by a first spring  15  installed at the first rotation axis  14 , so that it may return to the initial position. 
         [0051]    In this case, one end part of the first spring  15  may be fixed to a fixing protrusion  13 a formed at one side of the upper part of the claw  13 , and the other end part of the first spring  15  may be fixed to the base plate  10 . Accordingly, when the hood is closed, the claw  13  may rotate downwardly as receiving the force from the hood striker  12 , and when the hood is opened, the claw  13  may rotate upwardly due to elastic restoring force as the restraint force of the pawl  16  is released, and thus, the hood striker  12  may move upwardly. 
         [0052]    In relation to the claw  13 , a stop groove  13   b  may be formed at the right side of the upper left end part on the base plate  10 . When the hood striker  12  is inserted into the stop groove  13   b,  the closed state of the hood may be maintained, and when the hood striker  12  comes out of the stop groove  13   b,  the hood may be opened. 
         [0053]    The claw  13  may include a first stop end  13   c  protruding from the left middle and a second stop end  13   d  protruding therebelow. When the hood is opened, the first stop end  13   c  and the second stop end  13   d  may be sequentially stopped by the stop protrusion  16   a,  so that the rotation of the claw  13  is restrained in two steps. 
         [0054]    The pawl  16  may include a stop protrusion  16   a  protruding at the right middle. Thus, the first stop end  13   c  and the second stop end  13   d  may be stopped by the stop protrusion  16   a,  thereby restraining the rotation of the claw  13 . 
         [0055]    Additionally, the upper part of the pawl  16  may be hinge-coupled to a second rotation axis  17  installed at the left side of the base plate  10  and thus its lower part may be rotatable at the base plate  10 . The pawl  16  may be elastically supported by a second spring  18  installed at the second rotation axis  17 , so that it may return to the initial position. 
         [0056]    In this case, one end part of the second spring  18  may be fixed to a fixing protrusion  16   b  formed at the upper part of the pawl  16 , and the other end part of the second spring  18  may be fixed to the base plate  10 . Accordingly, when the hood is opened, the lower part of the pawl  16  may rotate to the left as the pawl  16  receives the force from the link  20 , and when the pawl  16  is released from the force of the link  20 , it may return to the original position. 
         [0057]    Here, the present invention may further include a pivot  19  and a link  20  installed at the base plate  10  in order to open the hood by operating the release handle twice inside a vehicle. 
         [0058]    The pivot  19  may have a rod shape having the greater height than the width, may have a connection aperture  19   a  at the lower part of the rod, and may be connected to a wire through the connection aperture  19   a.  The wire may be connected to the release handle inside a vehicle in order to connect the pivot  19  and the release handle. 
         [0059]    The center part of the pivot  19  may be hinge-coupled to a pivot axis  19   b  installed at the base plate  10 , and its upper part and lower part may be rotatable to the left and right on the basis of the center of the pivot axis  19   b.    
         [0060]    The link  20  may connect the pivot  10  and the pawl  16  horizontally, and thus, may pass the force from the release handle through the pivot  19  to the pawl  16 . 
         [0061]    The right end part of the link  20  may be connected to a third rotation axis  21  at the upper part of the pivot  19 , and the left end part of the link  20  may be connected to an operation axis  20   b  at the lower part of the pawl  16 , thereby rotating and moving the pawl  16  through the force passed through the pivot  19 . 
         [0062]    A third spring  22  may be installed at the third rotation axis  21  connected to the link  20  and the pivot  19 . One end part of the third spring  22  may be fixed at the link  20 , and the other end part of the third spring  22  may be fixed at the pivot  19 . When the link  20  receives the force through the pivot  19  and horizontally moves to the left during hood opening, it may rotate the pawl  16 . Also, when the release handle is released, the link  20  and the pivot  19  may return to the original positions and the link  20  may move upwardly due to the elastic restoring force of the third spring  22 . That is, by doing so, a first step lock state may change into a second step lock state. 
         [0063]    The pawl  16  may have a guide slot  23  formed at the lower part, and may be connected to the operation axis  20   b  of the link  20  through the guide slot  23  in order to guide the moving path of the operation axis  20   b.    
         [0064]    The guide slot  23  may include a first step slot  23   a  formed in the left and right horizontal direction, a second step slot  23   b  formed in the left and right horizontal direction, being spaced above the first step slot  23   a,  and a connection slot  23   c  for vertically connecting the first step slot  23   a  and the right end part of the second step slot  23   b  in order to change the lock state of the hood from the first step into the next second step. 
         [0065]    The claw  13  may include a circle-shaped protruding link restraint member  24  in order to restrain the upward rotation of the link  20 , and the link restraint member  24  may be coupled to the claw  13  through a pin. The claw  13 , the first stop end  13   c,  and the second stop end  13   d  may form the vertices of a triangle. 
         [0066]    Additionally, the link  20  may have a link groove  20   a  concavely formed at the upper surface with a smooth downward curvature, and the link groove  20   a  may convert the rotary motion of the pivot  20  into the horizontal linear motion of the link  20  through the contact with the outer circumference of the link restraint member  24 . 
         [0067]    An operational state of a two step link hood latch apparatus for vehicle having the above configuration according to the present invention will be described as follows. 
         [0068]      FIG. 3  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0069]      FIG. 4  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0070]      FIG. 5  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0071]      FIG. 6  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0072]      FIG. 7  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0073]      FIG. 8  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0074]      FIG. 9  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0075]      FIG. 10  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0076]      FIG. 11  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0077]      FIG. 12  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0078]      FIG. 13  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0079]      FIG. 14  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0080]      FIG. 15  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0081]      FIG. 16  is a view illustrating an operational state of a two step link hood latch apparatus when the hood is opened in  FIG. 2 . 
         [0082]    First, in order to open the hood, when a driver pulls out the release handle installed at the driver&#39;s seat inside the vehicle, its force may be applied to the lower part of the pivot  19  connected through the cable in the right direction and then may pull the lower part of the pivot  19 . 
         [0083]    When the lower part of the pivot  19  is pulled to the right through the force generated from the release handle, the upper part of the pivot  19  may rotate to the left on the basis of the pivot axis  19   b  at the center of the pivot  19 , and thus, may move the link  20  to the left. 
         [0084]    In this case, since the link groove  20   a,  which is concavely formed at the upper surface of the link  20  with a smooth downward curvature, contacts the outer circumference of the link restraint member  24 , it may restrain the upward rotation of the link  20  and may convert the rotary motion of the pivot  19  into the linear motion of the link  20 . 
         [0085]    Then, when the link  20  contacts the left end at the middle of the first step slot of the pawl  16  to push the pawl  16  to the left due to the force delivered through the pivot  19 , the lower part of the pawl  16  may rotate to the left, and thus, as the stop protrusion  16   a  of the pawl  16  rotates to the left, the first stop end  13   c  of the claw  13  previously stopped by the stop protrusion  16   a  may be released from the first step lock. 
         [0086]    Then, the claw  13  may rotate upwardly due to the elastic restoring force of the first spring  15 , and thus, the second stop end  13   d  of the claw  13  may be stopped by the stop protrusion  16   a.  Accordingly, the claw  13  may become a second step lock state. 
         [0087]    In this case, while the claw  13  rotates upwardly, the link restraint member  24  attached to the claw  13  may rotate upwardly, so that the link groove  20   a  at the upper part of the link  20  may be released from the link restraint member  24 . 
         [0088]    Next, when the release handle is released in the second stop lock state, as the force passed from the release handle to the pivot  19  is released, the lower part of the pivot  19  may rotate in a counterclockwise direction due to the elastic restoring force of the third spring  22 , and the upper part of the pivot  19  may rotate in a clockwise direction. As a result, as the link  20  connected to the upper part of the pivot  19  horizontally moves to the right, the operation axis  20   b  at the left end part of the link  20  may move from the left end part of the first step slot  23   a  of the pawl  16  to its middle again, and may pass through the middle of the first step slot  23   a.  By doing so, the operation axis  20   b  may rise from the first step slot  23   a  to the second step slot  23   b  through the connection slot  23   c  of the pawl  16 , due to the elastic restoring force of the third spring  22 . 
         [0089]    Thereafter, when a driver pulls the release handle for the second time, due to the force passed through the wire, as the lower part of the pivot  19  is pulled to the right again and the upper part of the pivot  19  rotates to the left, the link  20  may horizontally move to the left. 
         [0090]    Then, the operation axis  20   b  at the left end part of the link  20  may move to the left along the second slot  23   b  so as to contact the left end part of the second step slot  23   b,  thereby rotating the pawl  16  to the left. 
         [0091]    Thus, as the stop protrusion  16 a of the pawl  16  rotates to the left, the second stop end  13   d  of the claw  13  may be released from the stop protrusion  16   a,  and thus, the claw  13  may further rotate to the right. Accordingly, the insertion groove  11  of the claw  13  may be opened upwardly, and also the hood striker  12  may be completely released from the insertion groove  11  of the claw  13 . Finally, the hood may be opened upwardly. 
         [0092]    As described above, the operational state of the two step link hood latch apparatus is described when the hood is opened. An operating order when the hood is closed is the reverse order of the hood opening. However, when the hood is closed, since an operation of the release handle is not required, as the pawl  16  rotates due to the downward pressing force generated from the hood striker  12 , the link  20  and the pivot  19  may operate. 
         [0093]    Accordingly, according to the present invention, a safety lever of an existing hood may be removed, and a two step locking function may be performed on the hood latch itself through the guide slot  23  and the link  20  of the pawl  16  and the link restraint member  24  and the pivot  19  of the claw  13  in order to open the hood through the two step operation of the release handle inside a vehicle. Accordingly, existing inconvenience in putting the hand in an engine room to operate the safety lever in order to open the hood may be removed and merchantability may be improved. 
         [0094]    Additionally, first step and second step strokes may be adjusted through the first step slot  23   a  and the second step slot  23   b  of the pawl  16 , and the pivot  19  and the link  20  may be connected to a wire connected to the release handle in order to deliver the force occurring at the release handle to the pawl  16  through the pivot  19  and the link  20 , so that operability of the release handle may be constantly implemented. 
         [0095]    A two step link hood latch apparatus for vehicle according to the present invention has the following advantages. 
         [0096]    First, a safety lever of an existing hood is removed, and a two step locking function is performed on a hood latch itself through a slot and a link of a pawl, and a link restraint member and a pivot of a claw, in order to open the hood through the two step operation of a release handle inside a vehicle. Accordingly, existing inconvenience in putting the hand in an engine room to operate the safety lever in order to open the hood is removed and merchantability may be improved. 
         [0097]    Second, first step and second step strokes are adjusted through a first step slot and a second step slot of a pawl, and a pivot and a link are connected to a wire connected to a release handle in order to pass the force occurring at the release handle to the pawl through the pivot and link, so that operability of the release handle may be constantly implemented. 
         [0098]    Third, pedestrian protection performance may be improved by removing an existing safety lever. 
         [0099]    For convenience in explanation and accurate definition in the appended claims, the terms upper or lower, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0100]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.

Summary:
A two step link hood latch apparatus for a vehicle allows a hood to be opened only with an operation of a release handle inside a vehicle. The apparatus includes a claw, the pawl, a pivot, and a link. The claw is disposed at a base plate to be rotatable, restrains a hood striker through a stop groove, and is restrained to a pawl through first and second stop ends in first step and second step lock states. The pawl is disposed at the base plate to be rotatable, and restrains the rotation of the claw in steps by using the stop protrusion. The pivot is disposed at the base plate to be rotatable in a hinge structure, and transmits a pulling force generated from the release handle. The link connects the pivot and the pawl and rotates the pawl in linkage with the pivot.