Abstract:
An improved adjustable jack stand combines a ratchet and pawl height maintenance mechanism with a pin and hole mechanism wherein the holes in the post coordinate with the teeth in the post so that any engagement between the pawl and a tooth ensures that a pair of holes in the base and the post are aligned to receive a pin. Additionally, the pin defines a circular cylindrical shape, and each of the pin support sections likewise defines a corresponding bottom half of a circle, thereby exposing the targeted hole in the ratchet bar for easy viewing by the mechanic. An elongated tether is provided and has one section connected to the body and another section connected to the pin.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a jack stand and more particularly to a jack stand with a ratchet mechanism for controlling adjustment of the elevation of the saddle. 
     In the typical adjustable jack stand, there is a base that rests against the floor. A post extends out of and above the base and has a saddle on the exposed end. The load rests against the upper surface of the saddle. The elevation of the saddle can be changed by adjusting the length of the post that extends above the base. The desired elevation of the saddle, and of the load supported by the jack stand, is maintained typically in one of two ways. 
     In one embodiment, a plurality of holes are drilled through the post and spaced along the length thereof, and a pin is inserted through a hole in the post and a hole through the base to maintain the post at a predetermined elevation above the base. In another embodiment, a plurality of teeth formed on one edge of the post forms a ratchet that engages a pawl that is pivotally mounted on the base and attached to a lifting handle. 
     In the pin embodiment, it is typical for the pin to have a stay across both ends to prevent inadvertent withdrawal of the pin from the holes that would cause a sudden change in elevation and a commensurate shift in the load. However, this type of height adjustment mechanism also presents certain undesirable limitations. For example, removing one of the stays before removing the pin can be cumbersome, and mechanics tend to overlook replacing the stay or intentionally omitting the stay in order to avoid the inconvenience of dealing with the stay. Moreover, both the removed stay and the pin itself are easily misplaced in the work environment, rendering the jack stand inoperative until at least the pin is found. Additionally, it can be cumbersome to try to align the hole in the base with one of the holes in the post, and the weight of the post can cause it to slip out of alignment before the pin can be inserted through the aligned hole in the post. Such slippage can cause injury to the mechanic. 
     The ratchet and pawl mechanism does not require the mechanic to take any action to engage the pawl to the teeth on the post in the manner that holds the saddle at the desired elevation. However, the lifting handle can be moved in a manner that causes the pawl to disengage from the teeth on the post. It is possible that someone or something might inadvertently jostle the lifting handle while the jack stand is under load. If the pawl disengages from the post, then the saddle will undergo a sudden change of elevation that may cause the load to shift suddenly. Such sudden movements of the load can damage the load and/or the persons and property in the vicinity of the shifting load. 
     Moreover, there are a number of other ways for the pawl to be come disengaged from the tooth on the post. The pawl and the teeth on the post typically are cast iron that can break unexpectedly. The pivot pin that carries the pawl also can bend or break. When the height of the post is initially set by the operator of the jack stand, the pawl may not be properly engaged with a tooth, and operator may fail to check for or otherwise detect the improper engagement. 
     Thus, a need exists for an adjustable jack stand that overcomes these problems. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is a principal object of the present invention to provide an improved adjustable jack stand. 
     It is another principal object of the present invention to provide an improved adjustable jack stand that offers an extra measure of safety in use. 
     It is a further principal object of the present invention to provide an improved adjustable jack stand that offers an extra measure of safety in use without unduly inconveniencing the mechanic. 
     It is a still further principal object of the present invention to provide an improved adjustable jack stand that offers an extra measure of safety in use without unduly inconveniencing the mechanic by combining a pin and hole height maintenance mechanism with a ratchet and pawl mechanism. 
     It is yet another principal object of the present invention to provide an improved adjustable jack stand that offers an extra measure of safety in use without unduly inconveniencing the mechanic by combining a ratchet and pawl height maintenance mechanism with a pin and hole mechanism wherein the holes in the post coordinate with the teeth in the post so that any engagement between the pawl and a tooth ensures that a pair of holes in the base and the post are aligned to receive a pin. 
     Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
     To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the adjustable jack stand of the present invention comprises a ratchet and pawl height adjustment mechanism and a pin and hole height adjustment mechanism that are coordinated with each other. More particularly, the adjustable jack stand comprises a body that defines a hollow interior and defines at least one foot member configured to rest against the surface of the floor. The jack stand body also defines a slide opening that permits access into the interior of the jack stand body. 
     The jack stand includes an elongated ratchet bar that defines a plurality of teeth disposed side-by-side along most of the length of a first portion of one elongated side edge of the ratchet bar. The first portion of the ratchet bar is slidably received within the slide opening of the jack stand body in a manner that orients the elongated ratchet bar with its axis of elongation parallel to the vertical direction when the foot member is resting on the floor surface. The ratchet bar also defines a plurality of holes disposed transversely therethrough and spaced at predetermined distances along the length of the ratchet bar. Each hole in the ratchet bar has an entrance and an exit disposed opposite the entrance. Desirably, the entrance and exit of each hole of the ratchet bar is recessed. 
     The jack stand includes a pawl that is pivotally connected to the jack stand body and configured and disposed for selectively engaging at least one of the teeth of the ratchet bar so as to prevent the ratchet bar from movement toward the foot member. A lifting handle is connected in communication with the pawl and is configured and disposed to be selectively positionable so as to release the pawl from engaging the teeth of the ratchet bar. Desirably, the lifting handle is non-rotatably connected to the pawl. 
     The jack stand includes a safety pin that is removably disposed within one of the plurality of holes of the ratchet bar. The pin is configured to be removably received within each of the plurality of holes of the ratchet bar. The pin is configured to be selectively positionable to protrude beyond each entrance and exit of each hole of the ratchet bar when removably received therein. 
     The jack stand body defines at least one pair of pin support sections. A first pin support section is disposed on one side of the slide opening, and a second pin support section is disposed on the opposite side of the slide opening and aligned with the first pin support section. Each pin support section is configured to receive and support the safety pin when the safety pin is positioned to protrude beyond each entrance and exit of each hole of the ratchet bar. The locations of the holes of the ratchet bar and the locations of the teeth of the ratchet bar are coordinated with one another and with the pawl in a particular spatial relationship so that any engagement between the pawl and one of the teeth of the ratchet bar ensures that one of the holes in the ratchet bar is aligned with the pair of pin support sections in the jack stand body. 
     Desirably, the pin defines a circular cylindrical shape, and each of the pin support sections likewise defines a corresponding semi-circular shape. An elongated tether is provided and has one section connected to the body and another section connected to the pin. 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevated perspective view of a presently preferred embodiment of the jack stand of the present invention; 
     FIG. 2 is an elevated perspective view taken of the opposite side of the jack stand of FIG. 1; 
     FIG. 3 is an elevated perspective view of the jack stand of FIG. 1 with the saddle elevated and showing in phantom (dashed line) the safety pin removed from the safety position; 
     FIG. 4 is a side plan view with structure shown in phantom to illustrate operation of the pawl in relation to the lifting handle and the teeth of the ratchet bar; 
     FIG. 5A is an enlarged view of a partial section of the perspective view shown in FIG. 2; and 
     FIG. 5B is an enlarged partial section of the perspective view of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference now will be made in detail to the presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. The same numerals are assigned to the same components throughout the drawings and description. 
     A presently preferred embodiment of the jack stand of the present invention is shown in FIGS. 1-4. As shown in FIGS. 1-3 for example, the stand as a whole is designated generally by the numeral  10 . 
     As shown in FIG. 1 for example, jack stand  10  includes a jack stand body  12  which defines generally a base member  14  and a neck member  16  connected to base member  14 . As shown in FIG. 2 for example, the uppermost portion of base member  14  can be permanently attached (as by welding) to the lowermost portion or edge of neck member  16 . As shown in FIG. 1, base member  14  is desirably formed by 20-gauge steel that has been bent to form a hollow hexahedron that is open at the top and the bottom, and wherein each solid planar face is shaped as a trapezoid. As shown in FIGS. 1 and 2 for example, this four-sided shape which is hollow on the inside can be accomplished by bending a pair of 20 gauge stainless steel sheets to form two halves of the base member  14  and permanently joining (as by welding) the opposite side edges along a seam  17  to form the four facades of the four-sided base member. Thus, two of the four facades can include a seam  17 , and a generally trapezoidal-shaped window  15  can be defined in the other two facades. The lowermost edges of the base member can be formed to define at least one foot member  18 . As shown in FIGS. 1-3, the base member  14  is desirably configured to define four foot members  18 , and each foot member  18  is configured to rest against a floor surface (not shown). 
     As shown in FIGS. 1-3 for example, neck member  16  of jack stand body  12  is desirably defined by a hollow tubular member that has an hollow interior, is open at opposite ends and has a generally rectangular transverse cross-sectional profile. As shown in FIG. 4 for example, the upper free edge  13  of neck member  16  defines a slide opening  20 . Neck member  16  has a lower edge that can be permanently attached to the uppermost edge of base member  14  as by welding  19 . As shown in FIG. 1 for example, the neck member  16  is defined in part by a pair of opposed side panels  21 ,  23 . As shown in FIGS. 2 and 3 for example, the neck member  16  is also formed by a front panel  22  disposed between the side panels. As shown in FIG. 1 for example, a rear panel  24  is disposed opposite the front panel and between the side panels  21 ,  23 . As shown in FIG. 1 for example, a pair of opposed flanges  25 ,  26  can extend laterally from the side panels  21 ,  23  respectively, and beyond the rear panel  24  of neck member  16 . Desirably, the front panel  22  and the two side panels  21 ,  23  with each of these respective flanges  25 ,  26  is formed from a single bent sheet of 20 gauge steel to which the rear panel  24  formed of the same material is permanently attached as by welding. 
     As shown in FIGS. 2,  3  and  4  for example, the jack stand includes an elongated ratchet bar  28  (a.k.a. ratchet post). The ratchet bar  28  is configured to be slidably received through the slide opening  20  defined by the upper edge  13  of neck member  16  and pass through the hollow interior of neck member  16  and into the hollow interior of base member  14 . For a jack stand rated at 6-tons, the elongated portion of the ratchet bar can be formed from a steel I-bar that is two inches wide by one and one-half inches thick. 
     As shown in FIG. 2 for example, a saddle  30  is defined at one end of the ratchet bar  28 , and at the opposite end of the ratchet bar there is a distal end  29 . The saddle is configured in any known manner to receive and support on its upper face  31  the type of load that is intended to be supported by the jack stand. As shown in FIG. 3 for example, along a portion of one elongated side edge of the ratchet bar  28 , there is defined a plurality of teeth  32  that are disposed side-by-side along this portion, which spans the majority of the length of the ratchet bar. In the embodiment shown, the spacing between the teeth  32  is uniform, as are the size and shape of each of the teeth. For a jack stand rated at 6-tons, the distance between the underside support surface  33  (FIG. 4) of adjacent teeth  32  can be on the order of one and one sixteenth inches. As shown in FIG. 2 for example, at the distal end  29  of the ratchet bar  28 , there is a stop surface  34  that is configured and disposed for engaging a tab (described below). 
     As shown in FIGS. 2-4, the ratchet bar  28  defines a plurality of holes  36  that are disposed transversely therethrough. Each hole  36  has an entrance and an exit disposed opposite the entrance of the hole. The centers of the holes  36  are aligned with each other. Each hole  36  is spaced a predetermined distance from the nearest hole along the length of the ratchet bar  28 . This predetermined distance is determined by the strength of the material forming the ratchet bar as well as the maximum load that is to be supported by the jack stand. For a jack stand rated at 6-tons, the distance between the center points of adjacent holes can be on the order of one and one sixteenth inches, and the diameter of the hole can be on the order of nine-sixteenths of an inch. 
     As shown in FIG. 4 for example, the neck member  16  of the jack stand body  12  defines a slide opening  20  that is configured to slidably receive therethrough, the elongated ratchet bar  28  in a manner that orients the ratchet bar with the axis of elongation of the ratchet bar disposed parallel to the vertical direction when the foot members are resting on the floor surface (not shown). 
     As shown in FIG. 4 in phantom (dashed line and chain-dashed line) a pawl  38  is pivotally connected to the jack stand body  12  and in particular to the flanges  23 ,  25  of the neck member  16  of the jack stand body. As depicted in dashed line in FIG. 4, the pawl  38  is pivotally connected to the jack stand body and configured and disposed in selective engaging with one of the teeth  32  of the ratchet bar  28  so as to prevent the ratchet bar from movement toward the foot members  18 . The pawl  38  is also depicted in FIG. 4 in chain-dashed line to show an alternative orientation of the pawl  38  that does not permit pawl  38  to engage any teeth  32  and therefore does not prevent vertical movement of the ratchet bar  28 . A stop member  40  is also shown in FIG. 4 in dashed line and is configured and disposed to limit movement of the pawl  28  from being rotated past stop member  40 . 
     As shown in FIGS. 1-4, the jack stand includes a lifting handle  42  that is pivotally mounted to the jack stand and in particular to the neck member  16  of the body. As shown in FIG. 4, lifting handle  42  is non-rotatably connected to the pawl  38  so that as the handle moves about its axis of rotation  43  (FIG.  1 ), so too does the pawl  38  move about the same axis of rotation  43 . Moreover, the lifting handle  42  is configured and disposed for biasing the pawl  38  in a manner so that the pawl engages at least one of the teeth  32  of the ratchet bar  28  when the ratchet bar is disposed through the slide opening  20  and extending into the interior of the neck member  16 . When the pawl is so engaged with one of the teeth  32 , this prevents the ratchet bar from movement toward the foot member  18 . This orientation of the lifting handle  42  is biased by the gravitational force acting on the handle and is shown partly in solid line and partly in dashed line in FIG.  4 . As shown in dashed line in FIG. 4, the pawl  38  is oriented so as to engage the support surface  33  of one of the teeth shown in dashed line in FIG.  4 . 
     The chain-dashed line depiction of the lifting handle  42  in FIG. 4 shows the lifting handle being configured and disposed to be selectively positionable so as to release the pawl  38  from engaging the teeth  32  of the ratchet bar  28 . This release position of the pawl  38  relative to the teeth  32  is also shown in chain-dashed line in FIG.  4 . The mechanic would lift the handle  42  in opposition to the force of gravity in order to disengage the pawl from the teeth of the ratchet post  28 . 
     As shown in FIGS. 2 and 3 for example, a safety pin  44  is configured to be removably received within each of the plurality of holes  36  of the ratchet bar  28 . When the holes  36  are circular, then as shown in FIG. 2, the pin  44  defines a circular cylindrical shape. The pin  44  is configured to be positionable so as to protrude beyond each entrance and exit of each hole  36  of the ratchet bar  28  when the pin is removably received in the hole. The pin  44  is shown in dashed line in FIG. 3 when it is removed from insertion through one of the holes  36  and in solid line when it is inserted through one of the holes in the ratchet bar  28 . As shown in FIGS. 2 and 4, one end of pin  44  has a collar  45  that is larger than the entrance (and exit) of the hole  36  of the ratchet bar  28  and prevents insertion of the pin into the hole beyond the collar. In order to avoid misplacing the pin  44  when it is not inserted into a hole  36  in the ratchet post  28 , the pin is attached to the neck member  16  via an elongated tether  46  such as a metal chain or a piece of cord or elastic membrane. 
     As shown in FIGS. 1 and 2 for example, the body  12  defines at least one pair of pin support sections  48 ,  49 . Each pin support section  48  or  49  defines a semi-circular cut out formed in the upper edge  13  of one of the side panels  21 ,  23  of the neck member  16  of the body  12 . Thus, for the configuration of the safety pin shown, each pin support section  48 ,  49  is configured to receive and support the safety pin  44  when the safety pin is positioned to protrude beyond each entrance and exit of each hole  36  defined in the ratchet bar  28 . A first pin support section  49  is disposed on the side panel  21  of the neck member  16  defining one side of the slide opening as shown in FIG.  2 . As shown in FIG. 1, a second pin support section  48  is disposed on the opposite side panel  23  of the neck member  16  of the body  12  and is aligned with the first pin support section  49 . Thus, together the pair of pin support sections  48 ,  49  straddle the slide opening formed by the neck member  16  of the jack stand body  12 . Moreover, considering the typically elevated perspective of the mechanic, because the support section  48 ,  49  is defined as a bottom half of a circle, there is no upper half of the support section to obscure the hole  36  in the ratchet bar  28  from the mechanic&#39;s view. Thus, the mechanic can easily see when the support sections  48 ,  49  are aligned with the hole  36  in the ratchet bar  28  that is targeted for purposes of insertion of the pin  44  into the hole. 
     As shown in FIGS. 2-4 for example, the locations of the holes  36  in the ratchet post  28  and the locations of the teeth  32  along one elongated edge of the ratchet post are coordinated with one another and with the pawl  38  that is pivotally mounted in the neck member  16  in a particular spatial relationship so that any engagement between the pawl  38  and a tooth  32  on the post  28  ensures that a hole  36  in the post is precisely aligned with the pair of pin support sections  48 ,  49  in the body  12  of the jack stand  10 . In this way, the mechanic is assured that when the pawl  38  is engaged, then the pin support sections  48 ,  49  in the neck member  16  of the jack stand are going to be sufficiently aligned with one of the holes  36  in the ratchet post  28  for purposes of insertion of the pin  44  into the hole  36  so as to be supported by the pin support sections  48 ,  49 . 
     As shown in FIGS. 2 and 5A for example, a U-shaped slot  50  is defined through one of the side panels  21  forming the neck member  16 . This slot  50  isolates and defines a tab  52 . The purpose of this tab  52  is to permit the assembler of the jack stand to punch the tab inwardly to project into the interior space defined within the neck member  16 . 
     As shown in FIGS. 2 and 5B, the distal end  29  of the ratchet bar  28  defines a horizontally disposed stop flange  35 . The jack stand can be shipped with the ratchet bar  28  disassociated from the body  12  of the jack stand in order to reduce the size of the shipping carton and facilitate packing the jack stand inside the carton. Once the jack stand arrives at the destination where it is to be used, the assembler of the jack stand inserts the ratchet bar  28  into the slide opening  20  of the neck member  16  and allows the underside of the saddle  30  to rest against the upper edge  13  of the neck member  16 . As shown in FIG. 5A, the assembler can use a hammer  54  (with or without a punch) to force the tab  52  into the interior of the neck member  16 . As shown in FIG. 5B, with the tab  52  so oriented to project into the interior  55  of the jack body, the stop flange  35  at the distal end  29  of the ratchet bar  28  cannot bypass the inwardly projecting tab  52  as the saddle  30  of the ratchet bar  28  is lifted toward its maximum elevation. Moreover, because the central portions  27  of the ratchet bar  28  are recessed from the side edges  37  (FIG.  4 ), the tab  52  does not interfere with any of the holes  36 . 
     As an alternative to tab  52 , it is contemplated that a removable screw or a roll-pin or the like can be used to secure the ratchet bar  28  in the body  12 . 
     While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.