Abstract:
A hydraulic spool lock with a hydraulic spool housing, first and second hydraulic spools mounted within the hydraulic spool housing for independent selective movement with respect to the hydraulic spool housing, and a lock plunger movable mounted to the hydraulic spool housing. The present invention allows independent movement of the spools with respect to the hydraulic spool housing when the hydraulic spool lock is in the unlocked position. The present inventions prevents movement of the spools with respect to the hydraulic spool housing when the hydraulic spool lock is in a locked position.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates generally to a spool-locking device and specifically to a hydraulic spool lock for a two-spool directional control valve. The two-spool directional control valve is typically used to control a bucket and boom of a front-end loader. These valves typically have a single joystick handle used to control the two spools. These valves if accidentally moved can cause an unintended movement of a bucket and boom of a front-end loader and cause uncontrolled and unsafe movement of the bucket and boom of a front-end loader. 
   The invention specifically improves upon the spool locking devices typically used for a two-spool directional control valve. Although other devices in use may prevent the movement of the spools in a directional control valve, there have been several problems not addressed in current hydraulic spool locking devices. Specifically, it is a objective of our hydraulic spool lock to provide a device that is integral to the handle mounting housing or spool housing. 
   A further objective of the present invention is to create a device that is integral to a hydraulic spool housing or boot housing. 
   A further objective of the present invention is to provide a device which locks both spools and prevents movement of either spool. 
   A further objective of the present device is to provide for a locking between the plunger and the spools with direct contact between the plunger and the spools when the plunger is in the locked position. 
   A still further objective of the present device is to provide a locking device that is close-coupled to the two-spool directional control valve. 
   The means and method of accomplishing these and other objectives will become apparent from the following description of the invention. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is a hydraulic spool lock with a hydraulic spool housing, at least first and second hydraulic spools mounted within the hydraulic spool housing for independent selective movement with respect to the hydraulic spool housing, and a lock plunger movable mounted to the hydraulic spool housing for movement from an unlocked position permitting movement of the at least first and second hydraulic spools with respect to the hydraulic spool housing to a locked position preventing movement of the at least first and second spools with respect to the hydraulic housing. 
   The present invention hydraulic spool lock is also summarized as a plunger, a handle mounting housing, the plunger being slidingly mounted to the handle mounting housing for movement from an unlocked position to a locked position, a first and second lock member attached to the plunger, an end attached to the first and second lock member adapted for engaging a first spool and a second spool while in the locked position, and a boot housing supporting the handle mounting housing, and orifices in the boot housing adapted for sliding movement of the lock plunger, the first lock member, and the second lock member. 
   The present invention may also be summarized as a method for locking at least one spool mounted for movement within a hydraulic spool housing. The method comprising moving a plunger movably mounted to the hydraulic spool housing from an unlocked position free from engagement with the one spool to a locked position retentively engaging the one spool to prevent movement of the one spool relative to the hydraulic spool housing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a rear perspective view of the hydraulic spool lock attached to and in close proximity with the hydraulic valve body. 
       FIG. 2 . is an exploded perspective view of the hydraulic spool lock. 
       FIG. 3  is an exploded view of the joystick attachment, the pivot mounts, and the lock plunger for illustrating points of connection. 
       FIG. 4  is a front view of the lock plunger. 
       FIG. 5  is a perspective view of the hydraulic spool lock with the lock plunger in an unlocked position. 
       FIG. 6  is a perspective view of the hydraulic spool lock with the lock plunger in a locked position. 
       FIG. 7  is a sectional view taken along line  6 — 6  in  FIG. 5  and shows the lock plunger in an unlocked position. 
       FIG. 8  is a sectional view taken along line  7 — 7  in  FIG. 6  and shows the lock plunger in a locked position. 
       FIG. 9  is sectional view taken along line  8 — 8  in  FIG. 5  and shows the lock plunger in the unlocked position. 
       FIG. 10  is a sectional view taken along line  9 — 9  in  FIG. 6  and shows the lock plunger in a locked position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings, numeral  10  generally refers to the hydraulic spool lock. The hydraulic spool lock  10 , as seen in  FIG. 2 , has a hydraulic spool lock housing  12 . 
   The hydraulic spool housing, joystick housing, or boot housing  12  is generally in the shape of a rectangular box. The hydraulic spool housing  12  has a first housing side  14 , a second housing side  16 , a third housing side  18 , and a fourth housing side  20 . All four housing sides  14 ,  16 ,  18 ,  20  are joined in unitary assembly to form the rectangular box. Alternatively, the hydraulic spool housing  12  may be shaped in other fashions well known in the art. 
   The sides  14 ,  16 ,  18 ,  20  of the hydraulic spool housing  12  along with the joystick assembly  70  provide mounting surfaces for flexible protective boots commonly used in the art. 
   The hydraulic spool housing  12  has a back plate  22  that is attached to the hydraulic spool housing  12 . The back plate  22  has a first hydraulic spool orifice  32  and a second hydraulic spool orifice  34 . The third housing side  18  has first and second lock member orifices, respectively  172 ,  174 . A plunger orifice  176  is between the first and second lock member orifices  172 ,  174 . 
   The hydraulic spool housing  12  is held in place by screws  26  being put into screw holes  28 . The screw holes  28  extend through the hydraulic spool housing  12  and the spool assembly  40 . Alternatively, the hydraulic spool housing  12  may be attached to the spool assembly  40  by other means well known in the art. Alternatively, the hydraulic spool housing  12  may be integrated with the spool assembly  40 . 
   As seen in  FIG. 2  a fixed mount  36  is attached to the fourth housing side  20  and the back plate  22 . Alternatively, the fixed mount  36  may be attached to the fourth housing side  20 . Alternatively, the fixed mount  36  may be attached at other points known in the art. The fixed mount  36  has a fixed pivot mount  38  for attachment of universal ball joint  84 . 
   A spool assembly  40  is positioned adjacent to the hydraulic spool housing  12  at a position adjacent to the back plate  22 . The spool assembly  40  has a spool housing or spool assembly member  42  shaped as a rectangular box having a rectangular front face  44 . Alternatively, the spool assembly  40  may have a spool housing  42  shaped as other shapes well known in the art. 
   The spool assembly  40  is integrally attached to the hydraulic valve body  180 . Alternatively, the spool assembly  40  may be attached to the hydraulic valve body  180  by other means known in the art. 
   The rectangular front face  44  of the spool assembly  40  is configured to adjoin to the the back plate  22  of the hydraulic spool housing  12 . 
   Positioned upon the front face  44  of the spool housing  42  is a first spool  50  and a second spool  52 . The first spool  50  is moveably mounted in the spool assembly  40 . The second spool  52  is moveably mounted in the spool assembly  40 . 
   The first spool  50  has a first locking groove  58 , and a first pivot mount or first spool end  62 . The second spool  52  has a second spool mount  56  a second spool locking groove  60  and a second spool pivot mount or second spool end  64 . The spool mounts  54 ,  56  and pivot mounts or spool ends  62 ,  64  are separate pieces and joined together by screwing the pivot mounts into the spool bodies  54  and  56 . Alternatively, the pivot mounts may joined to the spool bodies by other means well known in the art. Alternatively, the pivot mounts may be integrally formed with the spool bodies  54  and  56  as one piece. 
   The first and second hydraulic spools  50 ,  52  are rotatable within the spool housing  42 . 
   A joystick assembly  70  is positioned on the hydraulic spool housing  12 . 
   Positioned adjacent the ball joint face  76  of the joystick assembly  70  is a first universal ball joint  80 , a second universal ball joint  82 , and a third universal ball joint  84 . Alternatively, the joystick assembly  70  may consist of other forms of universal joints well know in the art. 
   These universal ball joints  80 ,  82 ,  84  are attached to the joystick assembly  70  by a ball joint mount  86 . The ball joint mount  86  has a mount angular ring  88  that interfaces with the ball joints  80 ,  82 ,  84 . The ball joint mount  86  also has a mount stem  90  that is attached to the mount angular ring  88  and is attached to the ball joint face  76  by screw  92 . Alternatively, the mount stem  90  is attached to the ball joint face  76  using other means known in the art. 
   A joystick attachment orifice  94  is approximately centered on the joystick face  74  of the joystick assembly  70 . The joystick attachment orifice  94  is threaded for attachment to joystick rod  96 . The joystick rod  96  has a first end  98  and a second end  100 . The second joystick end  100  is adapted for attachment to joystick control interface  102 . 
   Joystick control interface  102  is spherical in shape for convenient manipulation in both the first axis  104  and second axis  106  as indicated in  FIG. 3 . The joystick also allows manipulation in the quadrants between axis  104  and  106 . 
   As seen in  FIG. 2 , the universal ball joints  82 ,  84  are attached to pivot mounts  64 , and  38 , respectively, each by bolt  108  and nut  110 . Universal ball joint  80  is connected to pivot mount  62  by a sliding stud  170 . As seen in  FIG. 2 , a dashed line indicates how bolt  108  and sliding stud  170  are placed through the universal ball joints  80 ,  82 ,  84 , the bolts  108  and sliding stud  170  are placed through a pivot mounts  62 ,  64 ,  38 , and nuts  110  placed upon the bolts  108  and sliding stud  170 . Alternatively, other fastening means known in the art may be used to attach the universal ball joints  80 ,  82 ,  84  to the pivot mounts  62 ,  64 ,  38 . Alternatively, as known in the art, different orientations of the pivot mount  38  and ball joints  80 ,  82 ,  84  may be used to vary the spool  50 ,  52  travel associated with movement of control interface  102  along an axis  104 ,  106 . 
     FIG. 3  illustrates the attachment of the universal ball joints  80 ,  82 ,  84  to the pivot mounts  62 ,  64 ,  38 . First pivot mount  62  is attached to first universal ball joint  80 . Second pivot mount  64  is attached to second universal ball joint  82 . Second hydraulic fixed pivot mount  38  is attached to third universal ball joint  84 . In assembly, the first spool  50  and the second spool  52  are fitted through first hydraulic spool orifice  32  and second hydraulic spool orifice  34 , respectively. The pivot mounts  62 ,  64 ,  38  are then joined to the universal ball joints  80 ,  82 ,  84 , respectively. 
   Referring to  FIG. 4 , a lock plunger  120  includes a plunger  122  having a first end  124  and a second end  126 . A knob  128  is located adjacent the plunger first end  124  and is attached to the plunger first end  124 . The lock plunger  120  includes a roll pin  132  that extends through the plunger  122  to rest upon the hold member  156 ; specifically, the roll pin  132  rests upon the front holdmember  158  and the back holdmember  160  in the roll pin cavity  164 . Alternatively, the roll pin  132  rests upon the front holdmember  158 . Alternatively, the roll pin  132  rests upon the back holdmember  160 . 
   The stop member  150  and the holdmember  156  may be referred to generally as the handle mounting housing  166 . 
   The lock plunger  120  has a bias member  134  extending the length of the plunger  122  from a point just below the roll pin  132  and just above a yoke  138 . In this embodiment, the bias member is a spring. Alternatively, the bias member  134  may be a compressible cylinder. Alternatively, the bias member  134  may be other devices that store potential energy well known in the art. 
   A fastener  136  holds the yoke  138  in assembly with plunger  122 . The lock plunger  120  has on the yoke  138  a first lock member  140  and a second lock member  142 . The first lock member  140  has a first arcuate bottom end  144  and a second arcuate bottom end  148 . The ends  144 ,  148  are designed to engage first locking groove  58  and second locking groove  60 , respectively. 
   Stop member  150  has a first end  152  and a second end  154 . The stop member first end  152  has affixed to it holdmember  156 . The stop member second end  154  is attached to the hydraulic spool housing  12 . As seen in  FIG. 9  and  FIG. 10  a spring cavity  162  exists within the stop member  150 . 
   The lock plunger  120  is assembled by inserting the plunger  122  through the stop member  150 . A spring  134  is then placed upon the plunger  122  and compressed against the stop member  150  such that the spring  134  lies in the spring cavity  162 . The yoke  138  with first lock member  140  and second lock member  142  attached is then slid into lock plunger orifices  172 ,  174  and upon the plunger  122  compressing the spring  134 . A fastener  136  is then placed upon the plunger  122 , as seen in  FIG. 4 . 
   While the hydraulic spool housing  12  and the handle mounting housing  166  have been referred to individually, they are formed in unitary assembly in close proximity. Alternatively, the hydraulic spool housing  12  and the handle mounting housing  166  may be separate pieces. 
   The hydraulic spool housing  12  possesses multiple features. The hydraulic spool housing  12  houses the first spool  50 , second spool  52 , joystick assembly  70 , and lock plunger  120 . The hydraulic spool housing may also serve as a boot mount. As seen in  FIG. 1 , the combination of features within one hydraulic spool housing allows for close proximity of the hydraulic spool housing  12  to the hydraulic valve body  180 . 
   In operation, as seen in  FIG. 5 ,  FIG. 7 , and  FIG. 9 , the plunger  122  is in an unlocked position when the spring  134  is compressed due to the roll pin  132  resting in the roll pin cavity  164 . The roll pin  132  can be moved to its locked position, resting upon the stop member  150 , by pulling the knob  128  and rotating the plunger  122  approximately 90 degrees such that the roll pin may travel through an index in the hold member  156 . This disengages the lock plunger  120  from the unlocked position permits the lock plunger  120  under force provided by the bias member  134  to move downwardly and cause the arcuate portions  144 ,  148  to engage the first locking groove and second locking groove  58 ,  60 . 
   The downward movement of the plunger  122  is stopped at the locked position when the roll pin  132  contacts the stop member  150 . Alternatively, downward movement of the plunger  122  is stopped at the locked position when the yoke  138  contacts the third housing side  18 . Alternatively, downward movement of the plunger  122  is stopped at the locked position when the fastener  136  contacts the third housing side  18 . Alternatively, the downward movement of the plunger  122  is stopped at the locked position when the first and second lock member arcuate bottom ends  144 ,  148  contacts the first and second spools, respectively  50 ,  52 . 
   As seen in  FIG. 6 ,  FIG. 8 , and  FIG. 10 , the spools  50 ,  52  are locked against movement. If the spools  50 ,  52  are not in their neutral position, the plunger  122  will ride on the large diameter of the first and second spools  50 ,  52  until the spool bodies  54 ,  56  move to their neutral positions at which time the lock plunger  120  will move downwardly and lock the spools  50 ,  52  against movement. 
   In reverse operation, the knob  128  can be pulled upwardly from the locked position, twisted approximately 90 degrees so that the roll pin  132  is in parallel alignment with the roll pin cavity  164  and released such that the spring  134  holds the roll pin  132  in the roll pin cavity  164 . This manipulation moves the hydraulic spool lock  10  from the locked to the unlocked position. 
   In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims.