Abstract:
A small or mini loader is operated by a platform standing on the ground or other surface supporting the loader, and at the rear of the machine. Hydraulic control levers operate drives on opposite sides of the machine, and the control levers are pulled rearwardly from a stopped position to effect the rearward drive. A pivoting panel is mounted on the rear of the frame and has a wall portion that protrudes outwardly from the rear of the machine. When the lower end of the pivoting panel engages an obstruction or other item that provides a force tending to move the lower end of the panel forwardly relative to the frame, an actuator arm will move to cause control levers that are in a rearward drive position to be moved to the stopped position.

Description:
[0001]    The present application is based on and claims the benefit of priority on U.S. provisional patent application Ser. No. 60/335,197, filed Nov. 1, 2001, the content of which is hereby incorporated by reference in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a pivoting panel on a work vehicle that is positioned so that if the work vehicle is being propelled and the panel engages an object that is either stationary or moving at lower velocity, the panel will pivot to mechanically disengage the drive control. In the form shown, a small loader is designed so that the operator is standing or walking on the ground at the rear of the loader when the loader moves. The hydraulic drive motors are operated through control valves that are movable to a position for providing reverse drive. When the pivoting panel is pivoted from engaging the operator while traveling in reverse the panel also operates to move the valve or valves to a neutral position to stop the rearward movement of the loader.  
           [0003]    Small or “mini” loaders, as well as other powered equipment, such as trenchers or garden equipment are made so the operator stands and walks at the rear of the machine. The equipment is power driven, and usually is operated from controls at the rear. The typical machine has hydraulic drive motors that are operated by valves mounted to be accessible to the operator at the rear of the machine. An internal combustion engine is used for powering a pump that provides the hydraulic fluid under pressure. When the machines are being driven in reverse, if the operator is standing still, it is desirable to have the drive disengaged if the operator is contacted. Also, if the unit is moving rearwardly and encounters a fixed object, it is desirable to have the drive disengage as well.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention relates to an apparatus that will move to disengage drive controls on a self propelled machine or vehicle using a mechanical linkage when a movable actuator panel is engaged by an object that is either stationary or is overtaken. The vehicle travel is stopped after the actuator panel moves a selected amount.  
           [0005]    The actuator panel as disclosed, is pivotally mounted on the machine frame, and is positioned to have a portion that extends out beyond a surface of the machine, so that the panel will be the first surface that is engaged by an object, toward which the machine may be moving. In the form shown, a pivoting wall portion or panel is mounted to extend from the rear of the machine, and is adjacent to the control levers for the hydraulic motors that are used for driving the machine in either forward or reverse direction.  
           [0006]    Specifically, the control levers operate hydraulic valves, one for each of two drive motors on opposite sides of the machine or vehicle. These motors are reversible and the individual valves permit skid steering of the machine or vehicle. Each of the controls is independently operable, and the panel includes an arm member that will engage a portion of the control lever and will move either one or both of the control levers to a neutral position when the actuator panel is moved in a direction opposite from the direction of movement of the machine. In other words, the free end of the actuator panel pivots forwardly, relative to the vehicle when the vehicle is in reverse and engages an operator, object or an obstacle. The pivoting movement of the panel before moving the control valves to neutral is sufficient so that momentary encounters do not cause the vehicle to be stopped, but if the vehicle does continue to travel toward the operator or obstacle, the control or controls will be moved to neutral to stop the machine or vehicle from such movement.  
           [0007]    Specifically, the actuator panel extends laterally across the width at the rear of the loader, which is the specific form of the machine shown, and has a lower portion that extends out beyond the rear edges of the frame of the loader. The upper portion of the panel is pivoted to the frame. The actuator panel carries an actuator arm or arms that has a width sufficient to span controls for both of the valves used for driving drive motors. The valve control levers have protruding arms or shafts that are engaged by the actuator arm when the panel is pivoted to its stopping position, and the levers are then moved to neutral. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a rear perspective view of a small skid steer loader including the improvements of the present invention;  
         [0009]    [0009]FIG. 2 is a rear view of the loader shown in FIG. 1;  
         [0010]    [0010]FIG. 3 is a schematic exploded view of a stop panel and mounting illustrating components used with the present invention;  
         [0011]    [0011]FIG. 4 is a sectional view taken generally along line  4 -- 4  in FIG. 2;  
         [0012]    [0012]FIG. 5 is a sectional view taken on the same sight line as FIG. 4 showing the actuator panel in position returning a drive control valve to a neutral position; and  
         [0013]    [0013]FIG. 6 is a sectional view taken along line  6 -- 6  in FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    Referring to FIG. 1, a small or mini loader indicated generally at  10  is a walk behind power loader that has a body or frame  12 . The frame  12  supports a track assembly  14  on each side of the loader propelling the loader  10  in forward and reverse directions through the use of drive hydraulic motors  16 A and  16 B. The drive motors are hydraulic motors operated from a pump  19  and a valve arrangement with a valve block shown generally at  20  at the upper end of a control panel for the loader. The pump  19  is driven by an internal combustion engine  45  mounted on the body or frame in a housing  17 .  
         [0015]    Each track assembly  14  includes a track frame  14 A, a drive sprocket  14 B and a front idler wheel  14 C over which a track  14 D is mounted. Bogie wheels  14 E are also provided on the track frame  14 A for support.  
         [0016]    The loader body or frame  12  has upright supports  22  at the rear of the frame, and these supports  22  extend upwardly a little higher than waist level of an operator standing on the ground. The upright supports in turn pivotally support base or rear ends of a lift arm assembly  24  on pivots  21 .  
         [0017]    The lift arm assembly  24  includes individual lift arms  24 A and  24 B, on opposite sides of the body or frame.  
         [0018]    The lift arm assembly  24  is raised and lowered with extendible and retractable double acting hydraulic cylinders or actuators  26 , operating with hydraulic pressure from the pump  19  and controlled by a valve having a control handle  32 . The valve controlled by handle  32  is part of the valve block  20 .  
         [0019]    The cylinders  26  (there is one on each side, and only one is shown) have base ends pivotally mounted as at  28  to the upright portions of the body or frame  12 , and the cylinders have extendible and retractable rods  29  that have rod ends that are pivotally mounted as at  30  to each lift arm of the lift arm assembly  24 . The lift arm assembly has a bucket  34  at the front controlled by a bucket control hydraulic cylinder  36 . The bucket control cylinder  36  that has its base end connected to an upright strut  38  on the lift arm assembly. The bucket control cylinder is operated with a control lever  40  that operates a valve in the valve block  20 . A further lever  42  operates a valve in valve block  20  used for auxiliary attachments connected with couplers  43  to the loader hydraulic valve block  20  and pump  19 .  
         [0020]    The frame  12 , in addition to the upright portions  22 , has frame side plates  46 A and  46 B that are spaced apart across the width of the machine, and are just to the inside of the lift arms  24 A and  24 B. It can be seen that these side plates  46 A and  46 B terminate along vertical rear edges  48  that define the rear of the machine frame. A lower rear frame panel  50  is fixed to the side plates, and includes a vertical portion  50 A and an inwardly sloped, downwardly extending portion  50 B that has openings for permitting airflow into the engine compartment.  
         [0021]    The operator&#39;s instrument and control station  52  is at the rear of the loader or machine, and this includes a panel  54  that has suitable instrumentation or gages  55  in place. Additionally, the operator station  52  includes the valve control levers  32 ,  40  and  42  for the hydraulic components such as the lift arms, the tilt cylinder, and auxiliary equipment, which are positioned on the right-hand side of the operator&#39;s station  52 .  
         [0022]    The valve control handles are mounted on the valve block  20 , and as can be seen in FIG. 3, the valve block  20  includes the valves attached to the respective control handles. The valve block  20  is mounted onto a generally horizontal support plate  56  that welded to the side plates  46 A and  46 B. In FIG. 3, the side plate  46 B is shown, but the other end of the support plate  56  would be welded or fixed to the side plate  46 A. Plate  56  is a structural member on the frame that supports the valve block  20  in its working position. A cover plate  60  is placed over the top of the support plate  56 . The valve block mounts underneath support plate  56  and openings or slots are provided for the various control handles.  
         [0023]    The motors  16 A and  16 B are for the right and left drive tracks, respectively, these motors are reversible hydraulic motors that are controlled by valves in the valve block. As shown in FIG. 3, the motor  16 A is controlled by a valve  62 A, and the motor  16 B is controlled by a valve  62 B. The valves have internal spools that are linearly slidable along the length of the valve body shown in FIG. 3, and these motor control valves are controlled by levers  64 A and  64 B, respectively. As shown schematically in FIGS. 4, 5 and  6 , each of the spool valves has a hub for pivotally mounting control levers on the valve block.  
         [0024]    The control lever  64 A is illustrated in FIG. 5 and it has a hub  66 A which is pivotally mounted about an axis  68 A to support ears  69 A on the valve block  20 . The hub  66 A has a depending arm  70 A (FIG. 4) that pivotally mounts to an ear on an end of a spool valve  72 A on a pivot axis  70 B. If the top of the valve control handle  64 A is moved in forward or reverse direction, the spool valve  72 A will also be moved, but in the opposite direction.  
         [0025]    The control handles  64 A and  64 B will pivot through an arc as illustrated in FIG. 4, and the center position is an off position where the motor  16 A is not being driven. Moving the control lever forwardly, to the line shown at  74 A will cause the valve spool  72 A to move to drive the motor  16 A in a forward direction, and moving the valve back to the solid line position shown in FIG. 4 will cause the spool  72 A to be moved in a position to drive the motor  16 A in a reverse direction. Thus, the tactile feel for the control levers is correlated with the direction of the drive.  
         [0026]    The control lever  64 B operates in the same way. The control levers are individually operable, but are close enough so that one hand can be used for simultaneously pulling both of the levers back or pushing both of the them forward for driving both motors at once, to drive the loader or other vehicle in a straight line either forwardly or in reverse.  
         [0027]    It can be seen that the hub  66 A, has an actuator shaft  78 A fixed thereto and the lever  64 B has an actuator rod or shaft  78 B (see FIG. 6). The rods or shafts  78 A and  78 B extend rearwardly. When the control levers and hubs move about their pivots the actuator shafts  78 A and  78 B swing in an arc about the same pivots  68 A or  68 B.  
         [0028]    In order to provide for a return of the control valves to a neutral position where the motor  16 A and  16 B would not be driven if the vehicle engages a stationary object, such as an operator standing still while the vehicle moves, or any other stationary object, an actuator panel assembly  80  is utilized.  
         [0029]    Referring to FIG. 3, the support plate  56  has a vertical rear panel portion  82  and this rear panel portion  82  has a pair of forwardly projecting mounting ears  84 A and  84 B thereon. The mounting ears  84 A and  84 B are also welded or fixed to the support plate  56  and are used for pivotally mounting an actuator panel assembly  86 . The actuator panel  86  has pivot brackets  88 A and  88 B, fixed to a formed outer plate  92  that has pivot brackets pivotally mounted on the ears  84 A and  84 B, respectively, with pivot pins shown at  90  in FIG. 3. The pivot pins are mounted so the pivot axis of plate  92  is close in horizontal direction to the levers of the valve and a short distance above the pivot  70 B, to obtain the desired mechanical advantage for releasing the levers when the panel assembly pivots, and to keep the linkages from getting too long.  
         [0030]    As shown in FIGS. 4 and 5, the pivot bracket  88 B is illustrated. The lower portions of the pivot or actuator plate extends through an opening  89  in the panel or wall  82 . The plate  92  is fixed to flanges  94  that provide reinforcing support for an inturned bottom portion  96  of the actuator plate  92 . Additionally, the pivot brackets  88 A and  88 B each have an extension  98 A and  98 B to which a separate spring shown schematically at  100  is attached. There is a spring  100  on each side of the actuator panel assembly  80 , anchored to the respective side walls. The spring load urges the actuator panel assembly to pivot in a clockwise direction as seen in FIGS. 4 and 5, so that normally the panel assembly moves to a position where the bottom of plate  92  extends rearwardly so that it protrudes from the vertical portion SA of the back wall  50 . The plate  92  also extends outwardly beyond the vertical edges  48  of the side panels  46 A and  46 B.  
         [0031]    The plate  92  also mounts an actuator arm bracket  104 , which bolts in position, and which can be adjusted through suitable slots  105  (FIG. 2) in the bracket  104 . The actuator bracket  104  is bent so that it extends forwardly toward the valve block  20  when the actuator panel assembly  80  is mounted on its pivots  90 . The bracket  104  has an upturned lip  106  that aligns with both of the shafts  78 A and  78 B. The lip  106  has edge recesses  108 A and  108 B (see FIGS. 3 and 6) that will cradle or receive the shafts  78 A and  78 B, respectively when the actuator panel assembly  80  is pushed inwardly about the pivots  90  against the spring load of the springs  100 . The pivot axis of pins  90 , the valve block and pivot axis  70 B are positioned close together so the actuator bracket  104  and rods  78 A are kept short. The pivot positions are selected to obtain adequate mechanical advantage for the panel actuation and a relatively short swing or movement of the lower end of plate  92 .  
         [0032]    It can be seen that when the actuator panel  86 , forming a part of the assembly  80  is moved to the position shown in FIG. 4 under the spring load from spring  100  it will be positioned so that the flange  106  of the bracket  104  is below the actuator shaft  74 A when the lever  64 A is in its position to drive the loader rearwardly. Both of the levers  64 A and  64 B are considered to be in the rearward position, in FIG. 4, and if there is a load that tends to pivot the actuator panel assembly  80  inwardly as indicated by the arrow  110 , the actuator panel will pivot about the pivots  90 , and the bracket  104  will move upwardly, so that the flange or lip  106  will engage the shaft  74 A and  74 B and will exert a force to pivot the control levers to their neutral position. This neutral position is shown in FIG. 5, and this will then cause the vehicle to stop so that there will be no further movement toward the operator or the obstacle. The panel assembly  80  also is stopped by engagement of a portion of the pivot brackets  88 A and  88 B with the wall  82 , as shown at  115  in FIG. 5. Other stops can be used.  
         [0033]    When the obstacle is cleared, or in other words when the springs  100  return the actuator panel to the solid line position shown in FIG. 4, the machine, or loader, can then be driven in reverse again. The actuator panel assembly  80  also is mechanically stopped in the position shown in FIG. 4 by the upper lip  93  of plate  92 , engaging the wall  82 . The machine always can be driven forwardly by moving the control levers to the forward dotted line position shown in FIG. 4, indicated by the line  74 A.  
         [0034]    The actuator panel assembly is for stopping the movement of the machine or vehicle is sturdy, and is reliable as well. The springs  100  provide adequate force for keeping the panel assembly  80  in its rearward position except when it encounters the operator or an obstacle. The actuator panel is not moved sufficiently to disengage the control levers on spool valves by casual bumps and very short movements. However, when the actuator panel is moved sufficiently, the lip  106  will engage the actuator shafts to move the control valves to their neutral position.  
         [0035]    The valve block  20  is shown schematically, since it is a standard valve block made by Walvoil, an Italian valve manufacturer. The control handles and the rods or shafts  78 A and  78 B can be replaced by a unitary formed handle of flat metal, where the upright handle portion and the rods that are engaged by the actuator are one piece. A hand rest or grip bracket  120  may also be mounted by the controls.  
         [0036]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.