Abstract:
A stabilizing jack ( 10 ) for securement to the underside of a recreational vehicle. The jack includes a channel frame ( 25 ) formed with longitudinal trunnion flanges. A longitudinal screw ( 50 ) is rotatably mounted in the channel and drives a trunnion ( 38 ) that rides between the trunnion flanges ( 22   a   , 22   b ). A support leg ( 30 ) is rotatably connected to the trunnion. Rotation of the screw drives the trunnion towards an outboard end of the jack and lowers the support leg to its supporting position.

Description:
This application claims priority from U.S. provisional application Ser. No. 60/429,508, filed Nov. 27, 2002. Application Ser. No. 60/429,508 is hereby incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   This invention relates generally to devices for stabilizing stationary recreational vehicles and more particularly to an improved stabilizer device mountable to the underside of such vehicle. 
   Recreational vehicles and trailers typically incorporate spring suspension systems mounted between the chassis frame and the wheels to provide a smooth ride during transit. While such suspension systems enhance passenger comfort and minimize vibration, they often detract from the stability of the passenger compartment when the vehicle is parked. For example, when passengers move about the compartment, the vehicle tends to rock both fore and aft as well as from side to side. Furthermore, this rocking motion is enhanced due to the inherent flexibility of the wheels and slight rolling thereof in response to forward and rearward weight shifting within the vehicle cabin. 
   The industry has addressed such vehicle stability concerns by developing various stabilizer jack devices and systems for use with the vehicles when stationary or parked. For example, such devices are disclosed in U.S. Pat. Nos. 3,565,396, 3,826,470, and 5,205,586. 
   One stabilizer jack device incorporates an elongated downwardly opening mounting channel formed with downwardly turned longitudinal marginal flanges. A cylindrical trunnion is formed with a transverse through a threaded bore for receipt of a drive screw rotatably mounted at one end of the mounting channel. The lateral opposite ends of the cylindrical trunnion pivotally mount a support leg extending longitudinally and downwardly therefrom. One end of a channel shaped strut has laterally spaced apart upwardly turned flanges and is pivotally mounted medially to the support leg and angles upwardly and longitudinally therefrom. A bracket at the opposite end of the mounting channel is formed with outwardly flared axle tabs for pivotally mounting to the opposite end of the strut. Difficulties with this stabilizer jack device were encountered in installed applications where the lateral flanges of the mounting channel and strut would spread laterally outwardly allowing the drive screw and strut to become racked and unbalanced in loading. This spreading of the upwardly turned flanges of the strut resulted in failure as the flanges slipped off of the axle tabs. 
   Another prior art jack device is a recreational vehicle stabilizer device having jack assemblies mounted at the laterally opposite extremities of telescopical jack housing channels for adjusting the stabilizer device to adapt to different width vehicles. While this device has enjoyed substantial commercial success, it is recognized that the stabilizing forces being directed through the jack housing to the vehicle frame allow for some degree of flex and play in the connections of such housing wherein the driving components of the jack assembly may rack or lock as weight is applied thereto from the interior of the vehicle. Furthermore, the jack assemblies resisted fore and aft longitudinal movement of the vehicle to only a minor extent. Thus, it was found that supplemental fore and aft restraint, supplied by for instance wheel blocks or chocks, was required. 
   In an effort to provide additional longitudinal restraint, other stabilizer devices provide a transverse frame member attached to the outer end of the jack housing and include angular extending support members attached between the lateral outer extremities of the transverse frame member and the jack assembly. Although these angular support members increase longitudinal stability, the additional components increase manufacturing costs, assembly time and complexity. 
   The foregoing illustrates limitations known to exist in present devices for stabilizing stationary recreational vehicles. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter. 
   SUMMARY OF THE INVENTION 
   In one aspect of the present invention, this is accomplished by providing a jack for securement to the underside of a recreational vehicle, the jack comprising: a channel; an elongated screw rotatably mounted to the channel; a movable trunnion threadedly attached to the screw and slidably carried by the channel; an elongated support leg pivotally attached to the trunnion, the support leg having two sides connected by a bottom portion, and an open top between the two sides opposite the bottom portion, the support leg having a plurality of elongated strength enhancers therein; struts pivotally attached to the channel and to the support leg; and a foot attached to an end of the support leg. 
   In another aspect of the present invention, this is accomplished by providing a jack for securement to the underside of a recreational vehicle, the jack comprising: a channel, the channel having an upper central portion, downward extending bends extending from opposite sides of the upper central portion, a top trunnion flange extending outward from each downward extending bend, a side extending downward from each top trunnion flange, and a bottom trunnion flange extending inward from each side; an elongated screw rotatably mounted to the channel; a movable trunnion threadedly attached to the screw and slidably carried by the channel, the trunnion fitting between the channel top trunnion flanges and the channel bottom trunnion flanges, there being a clearance space between the trunnion and the channel upper central portion; a support leg pivotally attached to the trunnion, the support leg having two sides connected by a bottom portion, and an open top between the two sides opposite the bottom portion; struts pivotally attached to the channel and to the support leg; and a foot attached to an end of the support leg. 
   In another aspect of the present invention, this is accomplished by providing a jack for securement to the underside of a recreational vehicle, the jack comprising: a channel; an elongated screw rotatably mounted to the channel; a movable trunnion threadedly attached to the screw and slidably carried by the channel; a support leg pivotally attached to the trunnion, the support leg having a slot therein, the slot being proximate a lower end of the support leg; struts pivotally attached to the channel and to the support leg; and a foot having a tab extending therefrom, the tab fitting into the support leg slot and being permanently attached to the support leg. 
   In another aspect of the present invention, this is accomplished by providing a jack for securement to the underside of a recreational vehicle, the jack comprising: a channel; an elongated screw rotatably mounted to the channel; a movable trunnion threadedly attached to the screw and slidably carried by the channel; an elongated support leg pivotally attached to the trunnion, the support leg having two sides connected by a bottom portion, and an open top between the two sides opposite the bottom portion; struts pivotally attached to the channel and to the support leg; an insert positioned within the support leg proximate the attachment of the struts to the support leg; a foot attached to an end of the support leg; and a plurality of welds, the welds being only between the foot and the support leg and between sides of the insert and sides of the support leg. 
   In another aspect of the present invention, this is accomplished by providing a jack for securement to the underside of a recreational vehicle, the jack comprising: a channel; an elongated screw rotatably mounted to the channel; a movable trunnion threadedly attached to the screw and slidably carried by the channel; an elongated support leg pivotally attached to the trunnion, the support leg having two sides connected by a bottom portion, and an open top between the two sides opposite the bottom portion; struts pivotally attached to the channel and to the support leg; an insert positioned within the support leg proximate the attachment of the struts to the support leg; and a foot attached to an end of the support leg, wherein the support leg and the channel each have a thickness no greater than 10 gauge. 
   The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       FIG. 1  is a perspective view of a stabilizer jack in an extended position according to an embodiment of the present invention; 
       FIG. 2  is a perspective view of the stabilizer jack shown in  FIG. 1 , shown in a retracted position; 
       FIG. 3  is an enlarged view of the outboard end of the stabilizer jack shown in  FIG. 1 ; 
       FIG. 4  is a perspective view of the stabilizer jack shown in  FIG. 1 , with portions of the channel cut away to show internal details; 
       FIG. 5  is a perspective view of a stabilizer jack leg; 
       FIG. 6  is a top view of the stabilizer jack leg shown in  FIG. 5 ; 
       FIG. 7  is an end view of the stabilizer jack leg shown in  FIG. 5 ; 
       FIG. 8  is a cross-sectional view of the stabilizer jack showing an insert within the stabilizer jack leg; 
       FIG. 9  is an end view of the stabilizer jack shown in  FIG. 1 ; 
       FIG. 10  is a perspective view of a T-bracket; 
       FIG. 11  is a perspective view of a foot pad; 
       FIG. 12  is a perspective view of the T-bracket shown in  FIG. 10 ; and 
       FIG. 13  is a schematic view of the T-bracket shown in  FIG. 10  illustrating the attachment of the channel and side stays to the T-bracket. 
   

   DETAILED DESCRIPTION 
     FIGS. 1 and 2  show a stabilizer jack  10  according to the present invention.  FIG. 1  shows the jack  10  in an extended or operative position and  FIG. 2  shows the jack  10  is a retracted or stowed position. The stabilizer jack  10  provides against component flexing that can lead to racking of the frame and consequent failure under load. In addition the stabilizer jack  10  is reliable in use and comprises a minimum number of components, which reduces manufacturing costs and assembly time. Furthermore, the jack  10  is configured to minimize weight while providing strength and durability. Preferably, channel  20  and leg or support leg  30  are formed from no thicker than 10 gauge steel, rather than the typical 8 gauge steel. More preferably, channel  20  and leg  30  are formed from 12 or 13 gauge steel. 
   Stabilizer jack  10  includes a channel  20  with attached T-bracket  60  that have a plurality of mounting holes  21  for attaching jack  10  to a frame component of a recreational vehicle or trailer (not shown). Usually, one jack  10  is fastened to the recreational vehicle near each corner of the recreational vehicle. 
   The stabilizer jack  10  generally includes a mounting channel  20  with T-bracket  60  that supports a drive screw  50  and movable trunnion  38 . Trunnion  38  has a threaded drive screw hole  40  extending radially through a mid-portion of the trunnion  38 . Drive screw  50  threadedly engages threaded hole  40 . A movable leg  30  is attached to channel  20  by trunnion  38 . Side stays or struts  44  are pivotally attached to T-bracket  60  and a mid-point of leg  30 . Foot pad  42  is attached to the free end of leg  30  and provides a ground support when the jack  10  is in the extended position. Foot pad  42  is preferably welded to leg  30  and helps prevent leg  30  from deflecting outward when under load. Foot pad  42  consists of a flat portion  80  and a curvilinear portion  81  with a tab  82  extending from the curvilinear portion. Tab  82  fits into a slot  43  in leg  30  and is welded to leg  30  on both sides of the tab  82 . Preferably, this is the only connection between foot pad  42  and leg  30 . 
   Channel  20  is formed as an elongated downwardly facing channel (see  FIGS. 8 and 9 ). Channel  20  includes a central upper mounting surface  25  with at least one mounting hole  21  for use in attaching channel  20  to the recreational vehicle. From the central upper surface  25 , two downward bends  27  are formed. Next, outwardly extending top trunnion flanges  22   b  are formed, followed by downwardly extending sides  23  and then inwardly extending returns, or bottom trunnion flanges  22   a . Flanges  22   a ,  22   b  provide support for and capture trunnion  38 , as shown in  FIG. 9 . The bends  27  between upper surface  25  and flanges  22   b  provide additional strengthening to channel  20 . In addition, these bends position upper surface  25  away from trunnion  38  and a clearance space  24  for the free ends  31  of leg  30  within channel  20 , as shown in  FIG. 8 . 
   Referring to  FIGS. 5 through 7 , leg  30  is generally formed as an elongated upwardly opening U-shaped channel. Leg  30  has a central portion consisting of two side lobes  32  that extend outwardly from a bottom  33  below the side lobes  32  and two sides  39  above the side lobes  32 . An elongated reinforcement lobe or dimple  34  is formed in each leg side  39 . In an upper end of leg  30 , a trunnion hole  37  is formed in each side  39 . As shown in  FIG. 9 , trunnion  38  fits into trunnion holes  37 . The free longitudinal edges of side  39  are flared outward at  36 . Outwardly extending flares  36  extend longitudinally from proximate the lower end of leg  30  to proximate the portion of leg  30  with trunnion holes  37  on both sides of leg  30 . Because side lobes  32  extend outward from sides  39  and bottom  33 , side lobes  32  strengthen leg  30 . Sides  39  are positioned a first distance  41  from one another. Side lobes  32  are positioned a second distance  45  from one another. The second distance  45  is greater than the first distance  41 . In addition, side lobes  32  extend outward from leg  30  a sufficient distance to permit side stays  44  to be attached to the outside of leg  30  without the use of additional spacers or bushings. Dimples  34  and flares  36  provide additional strengthening to leg  30 . A pair of aligned side stay bolt holes  35  are formed in each side lobe  32  for attachment of side stays  44  to leg  30 . Leg  30  can be used with other types of stabilizer jacks in addition to jack  10  of the present invention. 
   A U-shaped reinforcement insert  46  is provided within leg  30  proximate bolt holes  35 . Preferably, insert  46  is positioned as close to bolt holes  35  as possible without interfering with leg bolt  76  when bolt  76  is inserted through bolt holes  35 . Insert  46  preferably has two upwardly extending legs  48  with drive screw support slot  47  formed between legs  48 . Insert  46  is welded to leg  30 , preferably only adjacent the upper ends of legs  48 . Insert  46  is positioned adjacent bolt holes  35  and leg bolt  76  to keep leg  30  from deforming inwardly when leg bolt  76  and leg bolt nut  77  are tightened to attach side stays  44  to leg  30 . In addition to holding insert  46  in its desired position, the welding of insert  46  to leg  30  helps prevent outward bending of leg sides  39  when leg  30  is under compressive load. Preferably, only a single insert  46  is used. 
   The leg side lobes  32 , reinforcement dimples  34 , flares  36  along with the bends connecting the side lobes  32  to sides  39  and bottom  33  and reinforcement insert  46  strengthen leg  30  allowing thinner sheet metal, such as 12 or 13 gauge metal, to be used to form leg  30 . The channel trunnion flanges  22   a ,  22   b  along with bends  27  forming the offset upper surface  25  of channel  20  strengthen channel  20  also allowing thinner sheet metal, such as 12 or 13 gauge metal, to be used to form channel  20 . 
   A T-bracket  60  is attached to the outboard end of channel  20  and provides a fixed support for drive screw  50 . The outboard end of drive screw  50  has a hex head  54  attached thereto or formed thereon. The threaded end of drive screw  50  is threaded into the trunnion threaded hole  40 . Drive screw  50  can be adapted to be driven by a motor (not shown). 
   As, shown in  FIGS. 10 and 12 , T-bracket  60  is formed from a single piece of unwelded sheet metal and has a drive screw hole  63  formed in the center of front  65 . Front  65  is formed with a truncated pyramidal shape to strengthen T-bracket  60 . Top  64  extends from front  65  and has a plurality of mounting holes  21  formed therein. Sides  61  also extend from front  65  and each side  61  has a bolt hole  62  formed therein. A bottom flange  66  extends from front  65 . Bottom flange  66  preferably does not extend as far from front  65  at top  64  or sides  61 . Bottom flange  66  is used to strengthen T-bracket  60 . Referring to  FIGS. 1 and 13 , sides  61  of T-bracket  60  fit between sides  23  of channel  20  and side stays  44 . Two side stay bolts  70  are inserted through bolt holes  62 . Side stays  44 , T-bracket  60  and channel  20  are fastened together only by bolts  70  and side stay nuts  71 . Channel  20  holds the T-bracket  60  in place. 
   As shown in  FIG. 8 , when jack  10  is in the retracted position, drive screw  50  fits within drive screw support slot  47  in insert  46  with about a 1/16 inch clearance. Drive screw support slot  47  supports drive screw  50  when jack  10  is retracted to reduce flexing of drive screw  50  when the recreational vehicle is transported. 
   Preferably, the only welds used to form jack  10  are the three welds used to attach foot pad  42  to leg  30  and insert  46  to leg  30 , one between tab  82  and leg  30 , and one between each side of insert  46  and leg  30 . 
   In use, when stabilizer jack  10  is in the retracted position, shown in  FIG. 2 , a tool with a hex socket (not shown) is attached to hex head  54  and drive screw  50  is rotated in a first direction. As drive screw  50  rotates, trunnion  38 , which is threadedly engaged with drive screw  50 , moves towards T-bracket  60 , or outboard direction. As trunnion  38  moves outboard, the upper end of leg  30  also moves in the outboard direction. Because leg  30  is pivotally attached to channel  20  by both trunnion  38  and side stays  44 , outboard movement of the upper end of leg  30  causes pivotally movement of side stays  44  and extension of the lower end of leg  30  to the extended position as shown in  FIG. 1 . Rotation of drive screw  50  in the other direction causes movement of trunnion  38  towards the inboard end of channel  20  and corresponding retraction of leg  30  to the retracted or stowed position shown in  FIG. 2 . 
   An alternate embodiment of stabilizer jack  10  (not shown) is a telescopic jack, similar to the multi-purpose stabilizer assembly shown in U.S. Pat. No. 5,205,586, hereby incorporated by reference. Telescopic jack consists of two jacks  10  wherein the channels  20  are telescopically connected and extend across the width of a recreational vehicle. One channel  20  fits telescopically within the other channel  20 .