Abstract:
Jack stands having support arms that automatically rise to meet lifted loads are disclosed herein. According to one embodiment, a jack stand includes a base having a collar, a support arm, a locking mechanism, and a lifting mechanism. The support arm is movable within the collar and has a plurality of teeth defining grooves and ridges. The locking mechanism has a handle and a stopper and is rotatably coupled to the base at an axis of rotation for movement between a first position where the stopper engages at least one of the grooves to restrict the support arm from moving downwardly, and a second position where the support arm is movable upwardly and downwardly. The lifting mechanism is coupled to the base and is in communication with the support arm to automatically raise the support arm relative to the collar when the locking mechanism is moved to the second position.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 61/159,863, filed Mar. 13, 2009, the disclosure of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosed subject mater is related to jack stands used in supporting raised loads after the load has been jacked or lifted. In particular, the present disclosed subject matter is directed to jack stands that automatically raise the support arm, for example, a ratchet bar, into contact with the lifted load. 
       BACKGROUND 
       [0003]    Jack stands typically are employed for supporting a jacked or lifted load, such as a vehicle, safely and securely. For example, after a load has been jacked or lifted, one or more jack stands, typically paired jack stands to evenly support the load, are placed under the load to securely support the load in the lifted position. With the jack stands supporting the load, the lifting jack is removed; the jack stands replace the lifting jack as the support for the lifted load. 
         [0004]    One type of conventional jack stands has a base with a tubular collar for maintaining a column of a support arm. The support arm is formed of the column having an end terminating in a saddle, with a dimension larger than the collar and of a shape to support the lifted load, which it contacts. The column is movable in the collar to adjustable heights, for example, to the height of the contact with the lifted load. A portion of the column remains in the collar of the base, so that the height of the column is fixed by one or more pins that extend through aligned openings in the collar and the column. 
         [0005]    Another type of conventional jack stand  20  is shown in  FIGS. 1A-1C . The jack stand  20  has a base  22  that includes a support  24  and a collar  26 . The collar  26  supports a vertically adjustable support arm  27 , for example a ratchet bar  28  terminating in a saddle  29 . The ratchet bar  28  is movable within the collar  26 , between guide walls of the collar  26 . Teeth  30  extend along one side  28   a  of the ratchet bar  28 , while the opposite side  28   b  of the ratchet bar  28  is flat or smooth. The collar  26  includes an opening  31  defined by edges  31  a through which the ratchet bar  28  extends. The saddle  29  has a larger dimension than the opening  31 . The saddle  29  is shaped to contact and engage a load, such as an automobile, other motor vehicle, or the like. 
         [0006]    A ratchet mechanism in the collar  26  includes a pawl  32  connected to a handle  36  for moving the pawl  32 . The pawl  32  has a single engagement component  32   a  that engages between teeth  30  on the toothed side  28   a  of the ratchet bar  28 . The handle  36  limits the range of movement by the pawl  32  since movement of the handle  36  is limited by its ultimate abutment with the collar  26 . 
         [0007]    When lifting the ratchet bar  28  is desired, the handle  36  is moved, typically upward, so as to move the pawl  32  and its engagement component  32   a  upward and out of engagement with the teeth  30 . The ratchet bar  28  then is moved upward manually. Once the desired height is reached, the pawl  32  is moved back into engagement with the teeth  30  on the ratchet bar  28  by the handle  36  being moved downward, either controlled or in a free fall. 
         [0008]    These conventional jack stands exhibit drawbacks, in that they require the user to be in two-handed contact with them during their placement and locking under the load. As a result, the user is under the load during the entire jack stand placement operation, subjecting him to danger of a collapse while under the load. Additionally, the required two-handed contact requires coordination and skill by the user to attain the proper positioning of the support arm and secure locking thereof in the collar. 
       SUMMARY 
       [0009]    The present disclosed subject matter provides a jack stand including a support arm that automatically rises to the level of the lifted load. The disclosed jack stand is such that it minimizes the time the user must be under the load, and requires only one hand to operate. 
         [0010]    The disclosed jack stand includes a spring-biased handle, movable from an initial position to a disengaged position, where the handle structure is out of contact with the paired ratchet teeth of the support arm. This allows the ratchet bar to be forced upward by a lift mechanism or cylinder (e.g., a pneumatic cylinder) until the saddle of the support arm contacts the lifted load. Once the contact is made, the handle returns to a position, as biasing means (e.g., spring biasing, gravity biasing, etc.) cause it to contact the ratchet bar, where it engages a pair of ratchet teeth. This engagement locks the ratchet bar place, and the load is held securely. 
         [0011]    An embodiment is directed to a jack stand that includes a base with a collar and a support arm movable within the collar. There is a holding mechanism for moving between a first position, where the support arm is held in an engaged position, and a second position, where the holding mechanism is disengaged from the support arm, such that the support arm is movable. There is also a lifting mechanism (e.g., a pneumatic cylinder for driving a ram) that in turn moves the support arm automatically into contact with a load when the holding mechanism is in the second position, disengaged from the support arm. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Attention is now directed to the drawings, where like reference numerals and/or characters indicate corresponding or like components. In the drawings: 
           [0013]      FIGS. 1A and 1B  are perspective views of a conventional jack stand; 
           [0014]      FIG. 1C  is a cross sectional view of the conventional jack stand taken along line  1 C- 1 C of  FIG. 1A ; 
           [0015]      FIG. 2A  is a perspective view of a jack stand in accordance with the present disclosure; 
           [0016]      FIG. 2B  is a cross-sectional view of the jack stand of  FIG. 2A , taken along line  2 - 2 ; 
           [0017]      FIG. 2C  is a cross-sectional view of the handle of the jack stand of  FIG. 2A , taken along line  2 - 2 ; and, 
           [0018]      FIGS. 3A-3D  are cross-sectional views of the jack stand of  FIG. 2  in an exemplary operation, taken along line  2 - 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    In this document, references are made herein to directions such as up, down, upward, downward, upper, lower, inward, outward, all variations thereof, and the like. These references are exemplary only in order to describe the disclosed apparatus in a typical orientation or operation and are not independently limiting. 
         [0020]    Additionally, the term “ratchet” is used herein. A ratchet is a device, structure, mechanism, part of a machine, or the like, which effects movement in at least one direction, as will be appreciated by those skilled in the art. 
         [0021]      FIGS. 2A-2C  show the jack stand  100  of the disclosed subject matter according to an embodiment. The jack stand  100  includes a base or frame  122  that includes a support  123  and a collar  124 . A bore  126  extends through the collar  124 . A support arm  130  is formed of a ratchet bar  132  and a saddle  134 , at the upper end of the ratchet bar  132 . The support arm  130 , and in particular, the ratchet bar  132  is movable or adjustable (e.g., vertically) in the collar  124  (i.e., in the bore  126 ). A lifting mechanism  140 , mounted to the base  122  and connected to the ratchet bar  132 , provides lifting force (e.g., upward movement) to the support arm  130 . A handle mechanism  150 , that includes a movable handle  152 , controls engagement and disengagement of the ratchet bar  132 , allowing for the lifting and retention of the support arm  130 . 
         [0022]    The base or frame  122 , is, for example, shaped as a square or rectangular pyramid, so as to provide maximum stability to the jack stand  100 . The base  122 , collar  124  and support arm  130  are made of metal or any other appropriate material. 
         [0023]    The collar  124  supports the adjustable ratchet bar  132 , as walls  124   a - 124   d  horizontally confine the ratchet bar  132 . The walls  124   a - 124   d  form upper  124   q  and lower  124   r  openings, through which the ratchet bar  132  extends. One wall  124   d  includes a lateral opening  124   x  through which components of the handle mechanism  150  (detailed below) interact with the ratchet bar  132  to control its movement. An extension portion  160  of the collar  124  houses components of the handle mechanism  150 , such as discussed below. 
         [0024]    The ratchet bar  132  includes paired and aligned teeth  172  (also referred to as ratchet teeth) extending along opposite lateral sides  132   b,    132   c  of the ratchet bar  132 . The teeth  172  may be of a variety of shapes, such as sawtooth, and include grooves  174  and ridges  175  that accommodate unidirectional movement, i.e., in the upward (vertical) direction only. The paired teeth  172  protrude from a single side  132   d  of the ratchet bar  132 , while the opposite side  132   a  of the ratchet bar  132  is flat or smooth. The side  132   d  of the ratchet bar  132  also includes non-toothed portions  132   x,    132   x′,  proximate to the upper and lower edges of the ratchet bar  132 . 
         [0025]    The ratchet bar  132  terminates in a saddle  134  at its upper end. The saddle  134  is of at least one dimension, such as a length, greater than the upper opening  124   q  of the collar  124 , to serve as a travel limit for the ratchet bar  132 . The saddle  134  is configured to contact a load. A hollow bore  176  extends through the ratchet bar  132  and is, for example, closed by the saddle  134 . 
         [0026]    The lifting mechanism  140  provides force to lift the support arm  130  without any user interaction with the support arm  130 . In some embodiments, the lifting mechanism  140  includes a base plate  182  that supports a lift unit  183 . The lift unit  183  may include a cylinder body  184 , from which a movable ram  186  extends. The base plate  182  is attached to the base  122  (at the support  123 ) by mechanical fasteners (e.g., screws, bolts, etc.) or any other acceptable fastening technique (e.g., welds, adhesives, etc.). The cylinder body  184  and the ram  186  are positioned to sit within the bore  176  of the ratchet bar  132 , such that the ratchet bar  132  is movable (e.g., vertically). The ram  186  at its end  186   a  may be attached to the saddle  134  (e.g., by mechanical fasteners, welds, adhesives, etc.) if such additional securement is desired. 
         [0027]    Though other embodiments are clearly possible and contemplated herein (e.g., a spring-powered lift unit, an elastomer-powered lift unit, a hydraulic lift unit, a hybrid lift unit, etc.), it may be desirable for the lift unit  183  to be air driven, and to be, for example, an air bar or a pneumatic cylinder. The air bar or pneumatic cylinder may be such that it applies both upward force (i.e., toward the support arm  130 ), and downward force (i.e., toward the base  122 ), to push the support arm  130  and move it upward (e.g., vertically). 
         [0028]    The handle mechanism  150  includes the handle  152 , that is, for example, U-shaped, with an open end  152   a  and a closed end  152   b,  and oppositely disposed head portions  152   c  at the open end  152   a,  as shown in detail in  FIG. 2C . The handle  152  is pivotally mounted to the collar  124  by a pin  190 . A cross bar or stopper  192  extends across the open end  152   a  of the handle  152 . The head portions  152   c  of the handle  152  are mounted on the outer sides  160   x  of the column extension portion  160 , and both head portions  152   c  receive the pin  190  and the cross bar  192 . 
         [0029]    The extension portion  160  includes a front wall  160   a  that is common with the wall  124   d  of the collar  124 , lateral walls and a rear wall  160   d,  that is, for example V-shaped. The lateral walls may include identically shaped and positioned cut outs  194 , which the ends of the crossbar  192  extend through. The cut outs  194 , are, for example, rounded, and serve as tracks for the respective ends of the crossbar  192 , confining the movement of the crossbar  192 , and accordingly limiting the movement of the handle  152 . The cross bar  192  is of a diameter to seat within grooves  174  of the ratchet bar  132 . The cross bar  192  is movable over a range of positions, from within the grooves  174  of the ratchet teeth  172 , to out of contact with the ratchet teeth  172 , and through the opening  124   x  in the wall  124   d/   160   a  to beyond the plane of the wall  124   d/   160   a.    
         [0030]    A spring  196 , coiled around the pin  190 , includes a straight arm  196   a  that presses against the cross-bar  192 , and a bent arm  196   b  that contacts the rear wall  160   d  of the extension portion  160 . In this arrangement, the spring  196  biases the handle  152  and the cross bar  192  inward (i.e., toward the ratchet bar  132 ), such that the cross bar  192  seats in corresponding grooves  174  ( FIGS. 2B and 3D ) or abuts the ratchet bar  132  ( FIG. 3A ) along the non-toothed portions  132   x  or  132   x′.  Alternately, the biasing formed by the spring  196  around the pin  190  may be replaced by gravity or weight biasing mechanisms. The handle  152  is movable with small amounts of manual force, such that once the cross bar  192  moves beyond the ratchet teeth  172 ), the lift unit  183  automatically moves the support arm  130  upward into contact with the lifted load. While the handle  152  is shown as requiring downward movement to separate the cross bar  192  from the ratchet teeth  172 , those skilled in the art will appreciate that the handle  152  may alternately be configured such that upward movement of the handle  152  separates the cross bar  192  from the ratchet teeth  172 . For example, the handle  152  may extend across the collar  124  instead of on one side of the collar  124  as shown. 
         [0031]    Attention is now directed to  FIGS. 3A-3D , in addition to  FIGS. 2A-2C , detailing an example operation of the jack stand  100  with respect to a load  200  that has been lifted to an elevation “d” off of the ground  202 . The load  200  may be, for example, an automobile or the like, having been lifted to the elevation “d” by a jack or the like. 
         [0032]      FIG. 3A  shows the jack stand  100  in a rest, initial, or storage position. In this position, the support arm  130  is at its lowest position and the saddle  134  may contact the opening  124   q  of the collar  124 . The ratchet bar  132  is configured such that in this position of the support arm  130 , the cross bar  192  abuts the non-toothed oppositely positioned straight portion  132   x  along the side  132   d  of the ratchet bar  132 . The spring  196  (via the straight arm  196   a  with leverage from the bent arm  196   b  abutting the rear wall  160   d ) forces the cross bar  192  against the non-toothed oppositely positioned straight portions  132   x,  with a force greater than that of the force from the lift unit  183 , holding the support arm  130  in place. The cross bar  192  is in the cut outs  194 , intermediate the ends. The load  200  is positioned a distance “d” from the ground  202 . 
         [0033]    In  FIG. 3B , the handle  152  is moved downward, as indicated by the arrow  204 , such that the cross bar  192  disengages the ratchet bar  132 , by moving out of contact with the teeth  172  of the ratchet bar  132 . The continued downward movement of the handle  152  (in the direction of the arrow  204 ) moves the cross bar  192  beyond the plane of the wall  124   d/   160   a  until the cross bar  192  contacts the outer ends of the cut outs  194 . The movement of the cross bar  192  compresses the spring  196 . Upon the aforementioned disengagement, the force from the lift unit  183  instantly moves the ram  186 , extending it out of the cylinder  184 . The support arm  130  is forced upward, until the saddle  134  contacts the load  200 , at the elevation “d”, as shown in  FIG. 3C . 
         [0034]    The handle  152  is typically released once brought to the position of  FIG. 3C , and instantly moves upward, in the direction of the arrow  206 , due to the biasing of the spring  196 . As shown in  FIG. 3D , the cross bar  192  then seats in corresponding grooves  174  of corresponding teeth  172  on the ratchet bar  132 , resulting in a locking engagement, sufficient to support the load. In this position, the cross bar  192  abuts the inner ends of the cut outs  194 , and the spring  196  has returned to a relaxed position. This locking engagement is maintained until the handle is moved in the direction of the arrow  204  and the support arm  130  is moved downward, such that the jack stand  100  returns to the initial or storage position of  FIG. 3A . 
         [0035]    Though not specifically shown in the accompanying drawings, those skilled in the art will appreciate that the support arm  130  and the collar  124 , for example, may include corresponding holes, and that a pin may be removably placed through the holes as an additional safety mechanism to keep the support arm  130  from unintentionally raising or lowering. 
         [0036]    While preferred embodiments have been described, so as to enable one of skill in the art to practice the disclosed subject matter, the preceding description is intended to be exemplary only. It should not be used to limit the scope of the disclosed subject matter, which should be determined by reference to the following claims.