The wing lock is a safety mechanism for a snow plow blade and is engaged when the plow blade is not in use. The safety mechanism is primarily a pin and tongue assembly which is actuated by an air, electric, or hydraulic cylinder tied to the truck on which the plow is mounted. The pin is protected by a collar and sleeve which are disposed below the actuator cylinder. The tongue is affixed on the support arm of the plow wing so that when the support arm is raised the tongue slides into a receiving position for the pin. The pin drops through the tongue to lock the blade. For use, the safety mechanism is activated or deactivated from the truck cabin by a lighted, electrical switch which sends a signal to the actuator to deploy or retract the pin so that the plow may be locked or unlocked.

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority under 35 U.S.C. §119(e) to U.S. Patent Application Ser. No. 61/475,964, entitled “Wing Lock for Side-Mounted Snow Plow,” and filed on Apr. 15, 2011, which application is now pending. The entire disclosure of that provisional patent application is hereby incorporated by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A “SEQUENTIAL LISTING,” A TABLE, OR COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISC 
     Not applicable. 
     BACKGROUND 
     1. Field of the Invention 
     This invention relates to plows for vehicles, trucks and snow plows, and more particularly to such a safety device which may be selectively engaged to lock and unlock a snow plow wing from a remote location such as the vehicle cabin. 
     2. Description of the Related Art 
     Snow removal has been a problem for as long as motorized vehicles have used public roadways for transportation. In response to the task of removing significant quantities of snow away from roadways, driveways and parking lots, many different types of snow plowing arrangements have been invented. For example, snow plow blades may be mounted either to the front of the plow vehicle, to the side of the vehicle, or both. Side-mounted snow plow blades are frequently called wings. 
     Side-mounted snow plow wings are deployed to the vehicle side for use and retracted to an upright position when not in use or when the vehicle is traveling between uses. A joystick in the cabin of the truck is typically used by the driver to move the wing between deployed and retracted positions. However, the only current means to safely lock a retracted wing and prevent it from dropping down into a deployed position is by manually attaching safety chains. Safety chains are located on the exterior side of a truck where the wing is located and the chains are fastened between the vehicle and the wing. A wing can only be deployed when a safety chain is detached. Thus, when wings are needed to be deployed the driver must exit the vehicle cabin in order to manually latch or detach the safety chains. Exiting the cabin presents a number of hazards to the driver. Oncoming and passing traffic may not see the driver in adverse weather conditions where visibility can be very low. Bad roads can make it difficult for oncoming traffic to avoid a collision with an exposed driver. During implementation or removal of the safety chain, the chain may break and cause the wing to drop unexpectedly, injuring the driver. For these and other safety reasons, there is a need in the industry to reliably lock a snow plow blade into a predictable and secure position. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention for a wing lock for side-mounted snow plow wings generally comprises a pin assembly with actuating means and a pin receiving means. The pin assembly comprises a pin disposed and protected inside of a sealed sleeve or tube which is joined with an actuator cylinder via a collar. In the preferred embodiment, the pin assembly is affixed to the plow or truck frame by a support tower and base. All aspects of the base and support tower structures will necessarily vary between models of trucks and snow removal vehicles. The pin receiving means first comprises a tongue which may be affixed to the support arm of the snow plow wing. The pin receiving means also comprises one or two holes a portion of the base. The two pin receiving means cooperate to receive the pin and thereby lock the wing. The snow plow operator uses an electrical control switch or other trigger with an indicator light to trigger or signal the actuator cylinder to either unlock or release and lock the wing of the snow plow with the pin. 
     For use, the switch is engaged, the pin retracts, the light illuminates, and the wing is ready for operation. Upon engagement of the switch an electrical signal is transferred to the actuator which may be an air actuator or an electrical or hydraulic actuator. After the pin has retracted and cleared the tongue receiving means, the wing is unlocked and the driver may control the wing by joystick or other known method. Previously, the joystick could only control the support arms or mechanisms supporting the wings of the snow plow after the manual removal of safety chains. The present invention will dispose of any such need and also provide the ability to safely engage, disengage, and re-engage the snow plow wing from the safe, remote confines of the cabin of the plow vehicle. 
     In other terms, the present invention can be understood to be a latch for securing a snow plow wing in an upright, stowed position by incorporating a locking member, a cooperating member to receive the locking member, a holding member whereby the holding member selectively stores or releases the locking member to move to the cooperating member, and then a signaling means which activates the holding member to optionally hold or release the locking member. 
     By using the present invention, the operator enters the cabin of the truck once and remains in the cabin throughout his plow route. No safety chain is needed or used during the plowing operation. If a chain is still used for long-term storage of the truck and side-mounted plow the chain would be detached only once before operation and in the shelter of the garage or shop. The chain would then remain detached until the vehicle is returned to the garage or shop. At any time during a plowing route, the operator may retract and lock the wing into an upright position without exiting the vehicle cabin. With the present invention, the wing remains safely pinned in the upright position, but ready for immediate deployment and then use. With the use of the present wing lock, the accidental lowering of the snow plow wing because of hydraulic or other component failures is prevented. For use, the operator merely engages the deployment electrical switch pre-installed or integrated into the dash of the truck cabin. Such implementation will be particularly useful in areas where the snow plow wings are frequently moved up and down, such as when plowing and maneuvering in urban settings. 
     The foregoing has outlined, in general, the physical aspects of the invention and is to serve as an aid to better understanding the more complete detailed description which is to follow. In reference to such, there is to be a clear understanding that the present invention is not limited to the method or detail of construction, fabrication, material, or application of use described and illustrated herein. Any other variation of fabrication, use, or application should be considered apparent as an alternative embodiment of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings further describe by illustration, the advantages and objects of the present invention. Each drawing is referenced by corresponding figure reference characters within the “DETAILED DESCRIPTION OF THE INVENTION” section to follow. 
         FIG. 1  is a partial, side elevation view of a common truck having a known, side-mounted snow plow in a stowed position. 
         FIG. 2  is a partial, side elevation view of a common truck having a known, side-mounted snow plow in a position for plowing. 
         FIG. 3  is a partial rear, perspective view of a truck with a plow wing deployed for plowing and also demonstrating the present invention in use on the plow wing frame. 
         FIG. 4  is a partial, front plan view of a plow wing deployed for use and also showing the present invention mounted on the plow wing frame  22 . 
         FIG. 5  is a partial, front plan view of the plow wing in a retracted position and locked by the present invention. 
         FIG. 6  is a front plan view of the present invention mounted on a wing frame  22  and a partial view of a deployed wing support arm  23 . 
         FIG. 7  is a front plan view of the present invention mounted on a wing frame  22  and a partial view of a locked wing support arm  23 . 
         FIG. 8  is a partial, rear perspective view of the present invention mounted on a wing frame  22  and a partial view of a deployed wing support arm  23 . 
         FIG. 9  is a partial, rear perspective view of the present invention mounted on a wing frame  22  and a partial view of a locked wing support arm  23 . 
         FIG. 10  is a front, plan view of a hydraulic actuated wing lock  3  as from the front of the truck  1 . The wing lock  3  is demonstrated with the pin  12  in the locked position. 
         FIG. 11  is a schematic, cross-sectional view of an air actuated wing lock as from the front of the truck. The pin  12  of the wing lock is demonstrated in a retracted or unlocked position. 
         FIG. 12  is a schematic, cross-sectional view of the wing lock as from the front of the truck but with the actuating means removed and the pin  12  shown in phantom inside the sleeve  13  and in a locked position. 
         FIG. 13  is a schematic view of the electrical activation of the actuating means for the movement of the pin. 
         FIG. 14  is a schematic view of one manner in which to implement air actuated movement of the pin. 
         FIG. 15  is a schematic, cross-sectional view of a hydraulic-actuated wing lock as from the front of the truck. The pin  12  of the wing lock is demonstrated in a retracted or unlocked position. 
         FIG. 16  is a schematic, partial view of the wing lock as from the front of the truck but with the actuating means removed and the pin  12  shown in phantom inside the sleeve  13  and in a released and thus, locked position. 
         FIG. 16.1  schematically demonstrates one bolt plate option for affixing the support tower on the base of the wing lock. 
         FIG. 17  is a schematic view of one manner in which to implement hydraulic actuation for movement of the pin. 
         FIG. 18  is a schematic view of the electrical activation of the actuation means for the movement of the pin. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The wing lock  3  including the tongue  17  of the present invention is demonstrated in context, from afar in  FIGS. 1-3 .  FIGS. 1-3  illustrate a common truck  1  used for plowing. This plow vehicle has a snow plow wing  2  mounted on its side, meaning it has a side-mounted snow plow wing. Referring to  FIG. 1 , when the snow plow wing  2  is not in plowing use, the plow wing  2  is raised into a stowage position wherein the blade is folded, much like a wing, along the side of the truck  1 . The snow plow wing  2  must be deployed, or lowered for plowing use. See  FIGS. 2-3 . Portions of the drawing in  FIG. 1  are torn away to show the attachment points for the snow plow wing  2  to the truck  1  (or vehicle). In  FIGS. 1-3 , the location of the wing lock  3  embodiment and its tongue  17  are shown in relation to the truck  1 , the cabin  24 , the raised or lowered plow wing  2 , and the wing support arm  23 . 
     The front plan views of  FIGS. 4-5  further demonstrate the location of the wing lock  3  and tongue  17  relative to the plow wing  2 , the plow wing frame  22 , and the truck frame  21 . Referring to  FIG. 4 , the plow wing  2  is ready for plowing use because the wing lock  3  is unlocked and the pin is retracted into its sealed sleeve. In  FIG. 5 , the plow wing  2  is locked in its upright, safety position because the pin is released from its sleeve  13  and cleaves the holes of the tongue  17  and the base  14  and clevis  15  of the wing lock  3 . The tongue  17  is attached to the wing support arm  23 . The base is attached to the wing frame  22  that is affixed to the truck frame  21 . The plow wing  2  may again be prepared for deployment and plowing use by the driver of the truck who triggers the retraction of the pin  12  by the flip of a two-way switch in the truck cabin  24 . The movement of the pin  12  retraction is shown by an illustrated arrow in  FIG. 6 . With the retraction of the pin  12  into the sleeve  13 , the tongue  17  is again free from the pin  12  and the base  14  and may pivot with the wing support arm  23  and the plow wing  2  into a plowing position. 
     The components first shown in  FIGS. 3-5 , are set out, according to one embodiment of the wing lock  3 , in  FIGS. 6 and 7 . The clevis  15  and base  14  are substantially integrated and mounted on the wing frame  22  which is affixed to the truck frame  21 , or on the truck  1  directly. This demonstrates one embodiment, but the frame structures of the wing lock including the base configuration must be customized to the existing structures of various plow vehicles. According to the illustrated embodiment of the invention, the clevis  15  portion of the base support may be simply a plating of metal with a hole  153  therein to receive the elongated shaft, or pin  12 . See additional detail of the clevis hole in  FIG. 8 . 
     The clevis  15 , which is part of the lock assembly will be raised up away from the base of the frame a few inches in order to align with the tongue  17  on the plow wing  2 . The lock assembly, particularly the tongue  17  and clevis  15  must be manufactured on a bench in order to align them and their respective, first and second pin receiving holes or openings shown from the front in  FIGS. 6-7  and in perspective in  FIGS. 8-9 . During the manufacturing process the base  14  and the tongue  17  are properly tacked or welded to the truck frame  21  or wing frame  22  and the support arm  23 . In one embodiment such as that shown in  FIG. 5 , the support tower  19 , welded to the base  14 , is additionally supported by a gusset  141 . A series of gaps and corresponding spacers must be formed into the base  14  to allow clevis  15  and tongue  17  coordination. In one embodiment, the spacers may be 1 inch by 4 inches and then differ in heights. These gaps and spacers  151  and  152  are indicated in  FIGS. 6-9 . 
     The following materials and sizing are known to be preferred for a particularly common truck model. The clevis  15  will be fabricated from ½ inch plate metal having a hole  153  therein. The clevis  15  will be welded to the base  14 , but in the preferred embodiment may have a small gap with a first spacer  152  (around 1.5 inches) and a larger gap with a second spacer  151  (about 3 inches). See  FIGS. 6-9 . In the preferred embodiment, the support tower  19  is a 3 inch channel. The support tower  19  will be welded to the base  14 , but it may alternatively or additionally be bolted with our without a gusset.  FIG. 16.1  demonstrates one option for a bolt plate  811  and related bolt pattern of holes  812  for affixing the support tower  19  to the base  14  of the wing lock  3 . In this optional bolt plate pattern, the bottom of the plate is 4 inches by 9 inches and the bolt holes are ½ inch wide and 1 inch from the edge of the plate and 1 inch apart on all sides. A gusset  141 , if used, may be 3 inches by 3.5 inches thick. The tongue  17  is ½ inch by 4 inches by 9 inches with a 2 inch by 1.5 inch elongated hole  171  shown in  FIGS. 8 and 9 . The clevis  15  may be plating 9 inches by 4 inches by ½ inch and the upper two plates have a 1.25 inch hole  153  below and centered below the sleeve which houses the elongated shaft of the pin in a partially or wholly sealed manner. 
     Referring to  FIGS. 6 and 7 , the pin assembly is joined with the top of the support tower  19  by a tower arm plate  191 , fastening means  192 , a tower arm  193 , and a tower arm pin  194 . The tower arm plate  191  may be 5 inches in height. The fastening means  192  holding the tower arm  193  and tower arm pin  194  in place comprise bolts such as bracket bolts ⅜ inch by 1½ inches. Also, in the preferred embodiment, the tower arm pin  194  is measured and cut in conjunction with the throw of the cylinder, but is formed to be minimally longer so it will not reach the end of the throw of the cylinder and prevent any up and down play. The tower pin arm  194  should have its hole center half way between the widest dimension of the tower plate  191 . Regardless of the details of attachment for the vehicle's needs, the pin assembly is attached to the frame mounting components by an attachment means formed to hold the cylinder actuator  10  above or in a vertical position from the sleeve  13  and locking pin  12 . A more compact cylinder may result in a more compact pin assembly. In such case, the support tower  19 , pin and sleeve may also be shorter. 
     One manner in which to join the air actuating means with the locking pin  12  is by drilling a hole in the side of the air cylinder  10 . In another embodiment, the pin is drilled and tapped  36  (See  FIGS. 11 and 15 ) to ⅝ inch national fine (nf) thread (female) to receive the air cylinder  10  shaft and then a jam nut or lock nut  34  is used to keep the pin and cylinder in place. The pin  12  may be 1⅛ inch by 11 inches of cold roll tapered at one end  121  and drilled and tapped to ⅝ of at the upper end. The top end of the pin  12  receives the bottom of the cylinder's shaft. The collar  131  is installed on to the cylinder with a coupling means such as 5/16 inch coupling nuts  33  or any other bolting system that will coordinate with the four inch by four inch plate  103  of the cylinder's structure in order to hold the necessary configuration. The collar  131  over the sleeve  13  helps prevent corrosion because no moisture can penetrate the sleeve  13  itself. In the preferred embodiment, the sleeve  13  is split under the collar  131 . The split or seam  32  in the collar  131  allows the grease to fill the collar  131  and the grease further prevents corrosion. Cross-referencing  FIG. 11  with schematic views of  FIGS. 12 and 16 , one will appreciate the location of the 360 degree sealing weld  123  which is made around the point of joinder between the clevis  15  and the sleeve  13 . In the preferred embodiment, the sleeve  13  is approximately 11 inches long and 1.5 inch inside diameter (ID) by 2½ inches outside diameter (OD). In this embodiment, the other end of the sleeve  13  is welded to a 4 inch by 4 inch plate  103  which is then bolted through the bolt sleeve  35  to the cylinder  10  with bolts such as 5/16 inch by 1 inch bolts. Moisture and corrosion are non-factors because of the sealing effects of the combination of the collar  131  and grease with the sleeve  13 . Three grease zerts  132  ( 5/16 inch in the preferred case) are demonstrated in  FIGS. 11 ,  15 , and  6 - 7 . Any number or combination of grease zerts  132  may be used in order to accomplish the objectives of the invention. Any variation in specific hardware components may be used so long as the objectives of the invention are met. 
     As demonstrated in  FIGS. 6 ,  10 ,  12 , and  16 , the cylinder  10  and pin  12  have enough clearance so that the assembly can float or hang suspended in the sleeve  13 . The shaft of the locking pin  12  should be 1⅛ inches or lathed or machined or otherwise formed to reduce its circumference to allow sufficient welding and grease cavity clearance. The clearance of the pin  12  in the sleeve  13  coupled with the use of grease should prevent any issue with the pin  12  locking in the sleeve  13 . Also, the pin  12  will travel through the tongue  17  and clevis  15  holes more freely. The holes in the clevis  15  and the tongue  17  are drilled with clearance over the pin. In the preferred embodiment, ⅛ inch is sufficient overage. The tongue hole  171  is elongated for easier alignment and this feature is best appreciated from the partially exploded top perspective view of the pin locking mechanism in  FIGS. 8 and 9 . 
     The default, locked, pin-released position of the wing lock as actuated by the air cylinder is shown in  FIG. 7 . With the plow driver's trigger, the control valve  111  begins the release of air from the air supply  117  which activates the air cylinder  10 . See additional discussion of the air actuation schematic in  FIG. 14  below. In this embodiment, the air cylinder  10  is the actuating means to retract the pin  12  into the sleeve  13  and hold in it second, unlocked position, away from the tongue  17  as shown in  FIG. 6 . The tongue  17 , which is welded to the existing snow plow wing support arm  23 , is then free to pivot with the plow wing as the driver operator moves the wing  2  into plowing position. Air is supplied by any available means, but in one embodiment, an air supply  117  is tied to the air supply for the vehicle tailgate latch (not shown). From the control valve  111 , pressurized air travels to the cylinder  10  by the air lines  62 . After use in the air cylinder  10 , air is released out of the air exhaust  118  and through the exhaust filter  119 . The exhaust system is supported by and may be mounted to the support tower  19 . In this embodiment, one protection valve services two cylinders. 
       FIG. 13  presents a schematic representation of the supply of electricity to the air actuator of the present invention. Electricity must be supplied to the switch  31 . One embodiment uses an auxiliary switch already installed in the truck dashboard. The preferred lighted control switch  31  will have an amber light incorporated into the switch, but any known switch with light or other visual indicator and in any combination will suffice. It is preferred that any employed trigger or switch be remotely located away from the plow wing. he visual indication should be on the dashboard of the truck or in another location immediately around the driver. In the preferred embodiment, when the lock is disengaged the light of the lighted control switch  31  illuminates indicating to the driver that the wing is unlocked. When there is loss of power, such as when the switch is turned off or when the key is turned off, the cylinder  10  returns the pin  12  to the locked position. Electric over air control valve  111  is powered by a power source such as DC Voltage  54 . The surrounding components may have a weather pack connection  51  and have an in-cabin ground  52 . In one embodiment, 25 feet of 14 gauge 2 strand wire is implemented. A fuse holder and fuse (not shown) are provided to meet the needs of the provided actuator. The rating of the fuse will depend on the demands of the actuator. One known selection for the switch will be a lighted rocker switch or toggle  31 . The switch may have its own switch ground  53  also in the vehicle cabin  24 . Again, wiring should desirably be coordinated so that when the light is ‘on’, the wing lock is in the unlocked or useable position. This is one selection for the indicator light illumination. Of course, the opposite principle could be implemented and convey the same information. When the key to the vehicle is in the ‘off’ position, the wing lock will automatically return to the locked position for safety reasons. In the locked position, the wing may not be employed. 
       FIG. 14  demonstrates, in schematic, one known air actuation system as may be used in the present invention. The air supply line  117  receives an air supply. As stated in one embodiment, this will be from the tailgate supply line, but it may be taken from any other supply that has a tractor protection valve  61 . In one embodiment, the tractor protection valve is designed to shut off around 70 psi so that the truck will not lose all of its air pressure in the event of a catastrophe to the air to the wing lock. The supply imposes pressure on the air actuator. Through the air supply components, the electric over air control valve  111  applies pressure through air lines  62  and activates the air actuator or cylinder  10 . The exhaust filter  119  may be of a style like the Napa  3031  fuel filter. The exhaust line  118  may be a conduit such as a ⅜ inch fuel line hose (⅜ inch brass tee npt ⅜ barbed) for the exhaust side of the air supply components. In approximation, the air supply line  117  may be about ten inches of line while the exhaust line  118  may be about five feet of line. 
     As shown in the schematic, cross section in  FIG. 15 , the air supply and exhaust lines may be replaced with hydraulic lines  71  in the case that a hydraulic  72  is being used as the cylinder actuator (Part  10  in earlier drawings) moving the pin  12 . A comparison of  FIG. 10  with  FIG. 15  and then  FIG. 12  with  FIG. 16  illustrates that the remaining components of the wing lock will remain substantially as they were regardless of the mechanism driving the actuator. 
       FIG. 17  demonstrates a schematic representation of how a hydraulic actuator  72  may be coupled with the pin assembly. The hydraulic valve  91  may vary from truck to truck depending on the hydraulic system used by the truck. Hydraulic lines  71  will connect the hydraulic valve control  91  to the hydraulic actuator cylinder  72 . The hydraulic cylinder  72  will be similar to that demonstrated at Part  10  in  FIGS. 6 and 7 , but more similar to the cylinders shown in  FIGS. 10 and 15 . 
       FIG. 18  is a schematic representation of the supply of electricity to the hydraulic actuation of the present invention. While hydraulics have been used on snow plows to assist with application of resistance to the forces of snow and friction experienced during plowing, the use of hydraulics has not been contemplated for uses such as that presented by the wing lock  3  for the side-mounted snow plow. Again, the hydraulic valve  91  is initiated by the electrical switch  31  and is powered by a power source such as DC Voltage  54 . Again, the switch may have its own switch ground  53  also in the vehicle cabin  24 . Depending on the truck, an auxiliary circuit in the Hydraulic System may be available for use. The controls and valve may vary depending on the available circuitry. A fuse must be provided to a rating suited to the coil. The surrounding components may have a weather pack connection  51 . The electrical for the hydraulic actuator will be grounded by an in-cabin ground  52 . In one embodiment, 25 feet of 14 gauge 2 strand wire is implemented to connect with the valve control  91 . All switch options and lighting options will be available for the hydraulic actuator as well as the air actuator. See discussion above. Among the preferred hydraulic cylinders which may be implemented to meet the objectives of the present invention is the Prince™ Royal Plate 2-inch Bore Cylinder 6 Stroke cylinder. 
     During non-use, the wing  2  will be upright and the wing lock switch indicator light is off. The pin  12  returns to the down position through the clevis hole  153  and tongue  17  welded to the wing support arm  23  (existing). The wing  2  is securely locked until the operator drive activates the switch to the ‘on’ position. The light will then be illuminated. operated from a remote location such as the dashboard in the cabin  24  of the truck (see  FIG. 1 ) with a two-way, lighted control switch  31 . A switched wire (demonstrated in schematic of  FIG. 11 ) or other means communicates between the control valve  111  and the light control switch  31  on the dash. The mechanical use of the pin mounted to an actuator allows safe and predictable implementation or storage of a snow plow wing  2 . 
     In order to remove the preferred embodiment of the present invention from the truck, the tower arm pin  194  and  2  bracket bolts are removed. Once removed, the cylinder  10  and pin assembly may be pulled up and out of the sleeve  13 . Mud flaps should be provided on the box and wing to protect against damage by the wheels. 
     The preferred use of the present invention will be for a side-mounted snow plow, but the novel and useful aspects of the present invention will easily be applied to dump trucks, or any other piece of equipment or machinery requiring a locking point between one or more transitions in use. 
     While an air, electric, or hydraulic actuator may be employed without a significant change in operation, the hydraulic actuator is preferred. The alternative air actuator may be offered as a replacement or an option and may function better or worse depending on the desired applications and climate and conditions of operation. Snow plows are frequently used in extreme weather conditions and extreme cold is known to adversely effect the reliability of some actuators. Advancements in hydraulics make them preferred in implementing the use and objectives of the present invention. 
     It is further intended that any other embodiments of the present invention which result from any changes in application or method of use or operation, method of manufacture, shape, size, or material which are not specified within the detailed written description or illustrations contained herein yet are considered apparent or obvious to one skilled in the art are within the scope of the present invention.