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IDENTIFICATION OF RELATE APPLICATIONS 
   This patent application is related to co-pending U.S. patent application Ser. No. 12/140,893, entitled “Removable And Storable Wings For A Snow Plow Blade And Snow Removal System Used Therewith,” co-pending U.S. patent application Ser. No. 12/140,886, entitled “Snow Plow Blade Including Nut Retaining Plate,” co-pending U.S. patent application Ser. No. 12/140,732, entitled “Plow Quick Connect/Disconnect Hitch Mechanism,” co-pending U.S. patent application Ser. No. 12/140,635, entitled “V-Plow,” and co pending U.S. patent application Ser. No. 12/140,671, entitled “Plow Including Independently Moveable Wings,” all of which patent applications were filed on Jun. 17, 2008, and all of which patent applications are assigned to the assignee of the present application, and all five of which patent applications are hereby incorporated herein by reference in their entirety. 
   BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The present invention relates generally to snow removal systems for medium and light duty trucks, and particularly to a jack stand for safe and easy installation and removal of a snow plow blade on to a snow plow hitch component of the snow removal system. 
   The type of vehicle used in a snow removal system depends on the particular plowing application, and can include medium or light duty trucks, a skid or front-end loaders or commercial/government vehicles. Typically, the snow plowing apparatus is configured to be connected and disconnected from the snow plow vehicle so that the vehicle can be used in other applications, when not needed. 
   In order to provide the detachable plowing apparatus to the snow plow vehicle, a conventional snow removal system includes a hitch frame nose piece mounted at the front of the vehicle under the bumper, a hitch mechanism, removably mounted to the hitch frame nose piece on the vehicle, and a snow plow blade, mounted to the hitch mechanism. When attaching and removing snow plow equipment from the vehicle, the snow plow hitch mechanism must be raised to a vertical position so that it may be substantially aligned with and secured to the hitch on the front bumper of the vehicle. 
   Despite efforts to reduce the overall weight of the snow removal components, together the hitch mechanism and snow plow blade are extremely large and heavy, weighing up to several hundred pounds. In prior art snow removal systems, the plow operator must lift the system with pry bars or a hoist when performing this operation, and many times more than one individual is required. However, this can result in pinched fingers and back injuries to the operator(s). 
   It is accordingly the primary objective of the present invention that it provide an improved snow plow jack stand for a snow removal system and method of operating the same which allows the snow plow to be both connected to and disconnected from a vehicle easily and simply, without requiring tools. It is a related objective of the snow plow jack stand for a snow removal system of the present invention that it require little physical effort to connect or disconnect the snow plow from the vehicle. It is another related objective of the snow plow jack stand for a snow removal system of the present invention that the process of connecting or disconnecting the snow plow to or from the vehicle is so simple and easy to use that it can be done by a single person without requiring assistance. 
   It is a further objective of the snow plow jack stand for a snow removal system of the present invention that it be mechanically simple both in construction and in operation. It is a still further objective of the snow plow jack stand for a snow removal system of the present invention that is durable, long lasting and configured to be securably mounted to the snow plow hitch mechanism for easy availability whenever it is desired to remove the plow from the vehicle. 
   SUMMARY OF THE INVENTION 
   The disadvantages and limitations of the background art discussed above are overcome by the present invention. With this invention, a snow plow jack stand for a snow removal system is provided for safe and efficient removal, installation and storage of a snow plow blade system. 
   The jack stand of the present invention includes a stand base, a vertical shaft pivotally mounted thereto, a mounting bracket for securing the jack stand to a frame component of the hitch mechanism, upper and lower spring components and a locking mechanism for locking the vertical shaft into the desired position. 
   The jack stand has a lowered or operational position such that the jack stand base is positioned on the ground and the hitch mechanism is maintained at the proper vertical height before installation of the hitch mechanism on to the plowing vehicle. In the raised or stored position, the locking mechanism is released and the vertical shaft moves upwardly, lifting the stand base from ground level. The lower spring provides upward pressure on the locking mechanism so that the edges of the locking mechanism contact and grip the side edges of the vertical shaft locking the vertical shaft it into place. 
   When downward pressure is applied to the handle on the vertical shaft, the locking mechanism pivots downwardly releasing contact with the vertical shaft. When the locking mechanism is pivoted in this manner, a space is provided between the locking mechanism and the vertical shaft so that the shaft may slide up and down within the openings thereof. 
   As such, to maintain the plow hitch mechanism at the desired vertical position for installation on to the vehicle, the operator applies downward pressure to the handle of the vertical shaft causing the spring to expand and the stand base to rest on the ground. When the base contacts the ground and the handle is released, the lower spring urges the locking mechanism upwardly so that it engages the vertical shaft, thereby locking the jack in the proper position. 
   When it is desired to store the jack stand for plowing, downward pressure is applied to the release handle of the locking mechanism, releasing contact of the locking mechanism with the vertical shaft. The upper spring then releases from its tensioned or compressed position, causing the jack stand to leave the ground return to its raised, stored position. 
   The snow plow jack stand for a snow removal system of the present invention is of a construction which is both durable and long lasting, and which will require little or no maintenance to be provided by the user throughout its operating lifetime. The snow plow jack stand for a snow removal system of the present invention is also of inexpensive construction to enhance its market appeal and to thereby afford it the broadest possible market. Finally, all of the aforesaid advantages and objectives are achieved without incurring any substantial relative disadvantage. 

   
     DESCRIPTION OF THE DRAWINGS 
     These and other advantages of the present invention are best understood with reference to the drawings, in which: 
       FIG. 1  is a front perspective view of a snow plow jack stand for a snow removal system of the present invention, shown in the installed position on a snow plow hitch mechanism; 
       FIG. 2  is an exploded view the snow plow jack stand illustrated in  FIG. 1 ; 
       FIG. 3  is a perspective view of a mounting bracket for the snow plow jack stand illustrated in  FIGS. 1 and 2 ; 
       FIG. 4  is a perspective view of a locking bracket for the snow plow jack stand illustrated in  FIGS. 1 through 3 ; 
       FIG. 5  is partial, rear view of the snow plow jack stand illustrated in  FIGS. 1 through 4 , taken along the line  5 - 5  in  FIG. 1 ; 
       FIG. 6  is partial side view of the snow plow jack stand illustrated in  FIGS. 1 through 5 , taken along the line  6 - 6  in  FIG. 5 , shown in a lowered, operational position; 
       FIG. 7  is partial side view of the snow plow jack stand illustrated in  FIGS. 1 through 6 , shown in a raised, storage position; 
       FIG. 8  is partial view of the jack stand illustrated in  FIGS. 1 through 7 , taken along the line  8 - 8  in  FIG. 5 , shown in a locked position; and 
       FIG. 9  is partial view of the jack stand illustrated in  FIGS. 1 through 8 , shown in the an unlocked position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A snow plow jack stand  30  for a snow removal system of the present invention is illustrated in  FIGS. 1 through 10 . The snow plow jack stand  30  is illustrated on a conventional snow plow hitch mechanism, indicated generally at  32 , having a rear facing side  34  that will be attached to the front of a snow plow vehicle (not shown), and a front facing side  36 , which including an A-frame component  38  for supporting and connecting components, such as a snow plow blade (not shown) to the snow removal system, as will be known to those skilled in the art. The hitch mechanism  32  is provided as only one example of the type of hitch/lift mechanism design and/or frame assembly that can be utilized with the jack stand of the present invention. It will be appreciated that one or more features of the jack stand  30  of the present invention can be incorporated into any type of hitch mechanism/attachment frame assembly, with little or no modification thereof. 
   Referring first to  FIGS. 1 and 2 , the snow plow jack stand  30  includes a stand base  40  and a substantially vertically oriented shaft  42  pivotally mounted thereto. The jack stand  30  further includes a mounting bracket  44 , support bracket  46 , a plurality of overlapping locking plates  48   a  through  48   d  and upper and lower tensioning members/biasing members such as springs, indicated generally at  50  and  52 . It will be appreciated that each of the components of the jack stand are preferably constructed of a metal material, such as steel, aluminum or another lightweight metal, alloy or composite material capable of withstanding the environmental and wear conditions usually encountered during removal, storage, installation and operation of the snow removal system. 
   Turning to  FIG. 3 , in addition to  FIGS. 1 and 2 , the mounting bracket  44  includes a hitch mounting portion  56 , such as a substantially U-shaped channel member, comprising upper and lower, substantially parallel plates  58  and  60  and a connecting portion  62 . The upper plate  58  and lower plate  60  are spaced apart a distance  62  to provide an area  64  for accommodating a horizontally oriented mounting bar or brace  70  on the hitch mechanism  32 . The upper plate  58  includes at least one, and preferably two apertures  72  and  74  formed therein. Likewise, the lower plate  60  includes preferably two apertures  76  and  78 , configured to axially align with the apertures  72  and  74  in the upper plate  58 . 
   The mounting bracket  44  further includes an extension  80 , such as a square or tubular hollow member, secured at one end  82  to the mounting portion  56  and secured at the other end  84  to a substantially planar support plate  86 . The support plate  86  is substantially vertically oriented presenting a front face  88  configured to mate with the support bracket  46 , as described in more detail below. Preferably, the support plate  86  is substantially rectangular in shape, having mounting apertures  90 ,  92 ,  94  and  96  formed in respective corners thereof. An opening  98  is also formed in the support plate  86  for accommodating the locking plates  48   a - 48   d , as will also be described in more detail below. 
   Turning to  FIG. 4 , in addition to  FIGS. 1 and 2 , the support bracket  46  is preferably formed of a single piece of material and includes a substantially planar, vertically oriented back plate, indicated generally at  100 , having a rear side  102  that will mate with the front face  88  of the support plate  86  and a front side  104 . The back plate  100  includes mounting apertures  106 ,  108 ,  110  and  112  formed therein and positioned within the back plate  100  to axially align with the apertures  90 ,  92 ,  94  and  96  in the support plate. An opening  114  is also formed in the back plate  100  configured to substantially align with the opening  98  in the mounting bracket, which is also for accommodating the locking plates  48   a - 48   d , as will also be described in more detail below. Additional mounting apertures, such as aperture  116  can also be provided in the support bracket, as necessary. 
   Substantially horizontal and parallel upper and lower arms  118  and  120  extend forwardly from the front side  104  of the back plate  100  of the support bracket  44 . It will be appreciated that the arms  118  and  120  are preferably integrally formed with the back plate  100  of the support bracket  46 . The upper arm  118  includes an opening  122  formed therein. The opening  122  has side edges, indicated generally at  124 , an is of a size  126  configured to accommodate the shaft  42 . Likewise, the lower arm  120  includes an opening  128  formed therein. The opening  128  has side edges, indicated generally at  130 , an is of a size  132  configured to accommodate the outside edges  133  of the shaft  42 . The arms  118  and  120  are spaced apart a distance  125  apart so that the spring  52  and the locking plates  48   a  through  48   d  therebetween. 
   As best illustrated in  FIG. 2 , each of the locking plates  48   a  through  48   d  have a substantially flat plate body  134   a ,  134   b ,  134   c  and  134   d  including a small lip or protrusion  136   a ,  136   b ,  136   c  and  136   d , extending rearwardly therefrom. Each of the lips  136   a ,  136   b ,  136   c  and  136   d  are positioned to fit within the opening  114  in the back plate  100  of the support bracket  46  and are long enough to fit at least partially through the opening  98  in the mounting bracket  44 , as illustrated in  FIGS. 8 and 9 . Preferably, each of the lips  136   a ,  136   b ,  136   c  and  136   d  are of a size that permits at least some pivotal movement of the locking plates  48   a ,  48   b ,  48   c  and  48   d , respectively, when they are positioned within the openings  114  and  98 . 
   As illustrated in  FIG. 6 , each of the bottom three locking plates  48   b ,  48   c  and  48   d  includes a tab  138   b ,  138   c  and  138   d , respectively, extending forwardly from the plate body  134   b ,  134   c  and  134   d . Preferably, the top locking plate  48   a  includes an upwardly extending tab  140  that can be used as a jack release handle, as will be described. 
   Each of the locking plates  48   a ,  48   b ,  48   c  and  48   d  have an opening  142   a ,  142   b ,  142   c  and  142   d , respectively, formed within the plate body  134   a ,  134   b ,  134   c  and  134   d  thereof. Each opening  142   a  through  142   d  has perimetral side edges, indicated generally at  144   a ,  144   b ,  144   c  and  144   d , and is of a size configured to accommodate the outside perimetral edges  133  of the shaft  42  so that when the locking plates are positioned in a substantially horizontal manner on the shaft  42 , the shaft  42  may slide up and down within the openings  142   a  through  142   d.    
   The jack stand  30  is assembled by aligning the apertures  90 ,  92 ,  94  and  96  in the mounting bracket  44  with the mounting apertures  106 ,  108 ,  110  and  112  in the support bracket  46  and securing them together using a fastener such as bolts  148  and nuts  150 . Other types of fasteners can be used, as will be well known to those skilled in the art. 
   The locking plates  48   a  through  48   d  are positioned overlying each other so that the plate  48   a  is the top plate. The locking plates  48   a  through  48   d  are positioned so that the substantially overlapping lips  136   a  through  136   d  thereof are positioned through the opening  114  in the support bracket  46  and at least partially through the opening  98  in the mounting bracket. It will be appreciated that although four locking plates are illustrated in the Figs., any number of locking plates can be used, such as three or five locking plates, configured in the manner described herein. 
   The spring  52  is positioned underneath the lowest locking plate  48   d  between the upper and lower arms  118  and  120  of the support bracket  46 . When positioned between the arms  118  and  120 , an end  152  of the spring  52  contacts the bottom locking plate  48   d  and the other end  154  of the spring  52  contacts the lower arm  120  of the support bracket  46 . It will be appreciated that the spring  52  will be at least partially compressed, and under tension when properly positioned between the upper and lower arms of the support bracket  46 . As such, the locking plates  48   a  through  48   d , each having a lip engaging and pivotally fixed within the opening  114  in the support bracket  46  and the opening  98  in the mounting bracket, are disposed at an angle, such that the perimetral edges  144   a - d  of each of the apertures  142   a - d  of the locking plates  48   a - d  contact and grip the perimetral side edges  133  of the shaft  42 , as illustrated in  FIG. 8 . 
   A top end  182  of the shaft  42  includes a handle  184  for lowering the jack so that the stand base rests on the ground, as will be described herein. A bottom end  158  of the shaft  42  is inserted through a central opening  169  of the upper spring  50  and a protective sleeve or jacket  160  can be provided over the spring  52  to protect the user&#39;s fingers during operation of the jack stand  30 . The bottom end  158  of the shaft  52  is then inserted into the opening  122  of the upper arm  118 , through the openings  142   a  through  142   d  in the overlying locking plates  48   a  through  48   d , through a central opening  162  of the spring  52  and through the lower opening  128  in the lower arm  120 . The bottom end  158  of the shaft  42  includes coaxially aligned apertures  172  and  174  is pivotally secured to the stand base  40  by inserting a bolt  166  through the mounting aperture  168 , then through the apertures  172  and  174  and then through the aperture  170  in the stand base  40 . The bolt  166  is secured in place with a nut  180 . 
   The jack stand  30  is then installed on to the mounting brace  70  of the hitch mechanism  32 . The mounting brace  70  is preferably provided with pretapped or drilled apertures  190  on the top and bottom sides of the mounting brace  70 . The mounting brace  70  is positioned inside the area  64  between the upper and lower plates  58  and  60  of the mounting bracket  44 . A bolt  192  is inserted through the aperture  72  in the upper plate  58 , through the axially aligned apertures  190  in the mounting brace  70 , through the aperture  76  in the lower plate  60  of the mounting bracket  44  and secured with a nut  194 . Likewise, a bolt  198  is inserted through the aperture  74  in the upper plate  58 , through the axially aligned apertures  190  in the mounting brace  70 , through the aperture  78  in the lower plate  60  of the mounting bracket  44  and secured with a nut  200 . 
   Turning next to  FIGS. 6 through 9 , in addition to  FIGS. 1 through 5 , operation of the jack stand  30  is described. As illustrated in  FIG. 6 , the stand base  40  of the jack stand  30  is positioned on the ground or surface  210  in the lowered, operational position  220 , maintaining the hitch mechanism at a proper vertical level. It will be appreciated that the shaft  42  pivots with respect to the stand base  40  to account for mounting surfaces  210  that are not level. 
   As illustrated in  FIG. 7 , the jack stand  30  has a raised, storage position  212 , wherein the stand base is spaced apart from the ground, after installation of the hitch mechanism on to the plowing vehicle. The spring  52  provides upward pressure on the locking plates  48   a  through  48   d  and they are disposed at an angle, so that the edges  144   a  through  144   d  of the openings  142   a  through  142   d  contact and grip the side edges  133  of the shaft  42 , locking the vertical shaft  42  in place, as illustrated in  FIG. 8 . 
   It will be appreciated that the jack stand  30  of the present invention is configured to remain in a locked position as a fail safe. More particularly, unless there is downward pressure applied upward pressure applied to the handle  184  or handle  140 , the jack stand is in a locked position, so that the edges  144   a  through  144   d  of the openings  142   a  through  142   d  contact and grip the perimetral side edges  133  of the shaft  42 , locking the vertical shaft  42  in place, as illustrated in  FIG. 8 . 
   When downward pressure is applied to the handle  182  or to the handle  140  on the locking plate  48   a , the locking plates  48   a  through  48   d  pivot downwardly. As illustrated in  FIG. 9 , this action releases the vertical shaft, so that the edges  144   a  through  144   d  of the openings  142   a  through  142   d  no longer contact the side edges  133  of the shaft  42 . When the locking plates are pivoted in this manner, a space  214  is provided between the side edges  144  of the openings  142  in the locking plates and the shaft  42  may slide up and down within the openings thereof. 
   Accordingly, as illustrated in  FIGS. 5 and 6 , to maintain the plow hitch mechanism  32  at the desired vertical position, the operator applies downward pressure to the handle  184 , causing the locking plates  48   a  through  48   d  to pivot downwardly so that the edges  144   a - d  of the openings  144   a - d  are out of contact with the edges  133  of the vertical shaft  42 . The shaft  42  is pressed downwardly until the standbase contacts the ground. As soon as pressure is released from the handle  184 , upward pressure from the spring  52  on the locking plates  48   a - 48   d  pivots the locking plates back into contact with the edges  133  of the shaft  42 , providing the jack stand  30  with its lowered, operational position. 
   When it is desired to release the jack stand  30 , downward pressure is applied to the handle  140  of the top locking plate  42   a , releasing contact of the locking plates  48   a - 48   d  with the vertical shaft  42 . Spring  50  then releases from its tensioned or compressed position, causing the jack stand  30  to return to its raised, storage position  212 . 
   The snow plow jack stand of the present invention are of a construction which is both durable and long lasting, and which will require little or no maintenance to be provided by the user throughout its operating lifetime. The snow plow jack stand is also of inexpensive construction to enhance its market appeal and to thereby afford it the broadest possible market. Finally, all of the aforesaid advantages and objectives of the snow plow blade and wing extensions of the present invention are achieved without incurring any substantial relative disadvantage. 
   Although the foregoing description of the snow plow jack stand of the present invention have been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Summary:
A jack stand for a snow removal system including an easily vertically positionable frame retaining bracket and locking mechanism is provided. The jack stand is configurable between a lowered, operational position and a raised, stored position, wherein the jack stand includes a locking mechanism for retaining the base of the jack stand on the ground. When the jack stand is not needed, the locking mechanism is released, the jack stand is raised from the ground and the stand remains secured to the hitching mechanism and stored for further use thereof.