Abstract:
A mechanical control mechanism for the feed of a brush chipper is disclosed. The feed control bar has four positions: (1) forward or feed, (2) neutral, (3) reverse, and (4) stop. The hydraulic control valve has the three usual positions: (1) forward or feed, (2) neutral, (3) reverse. A function of the feed control bar is to provide the three function of the hydraulic control valve, plus the fourth in a fashion amenable to emergency situations. To these ends, the control bar has an extreme rearward position wherein the feed mechanism is stopped. The only permissible change to the stopped condition of the feed mechanism is to reverse the feed. Until a reset lever is manipulated, the hydraulic control valve cannot be put into a forward feed position.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Not applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   REFERENCE TO MICROFICHE APPENDIX 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to feed control for a brush chipper. More particularly, the invention relates to a method and apparatus for providing a stop position to the forward (or feed), neutral, and reverse positions presently associated with brush chipper mechanical feed bar mechanisms. The hydraulic control valve actuated by the feed bar has three positions: forward (or feed), neutral, and reverse. 
   2. Background Art 
   Feed control for a brush chipper presently takes one of two forms: (1) mechanical or (2) electrical. Electrical controls require a functioning source of electrical power such as a generator or battery. Mechanical control systems do not require electrical power, but have proved less versatile than the electrical systems in the past. 
   The feed wheels in a brush chipper are typically hydraulically driven. The flow of hydraulic fluid is controlled by a hydraulic control valve. Hydraulic control valves of the type used for brush chipper feed control have three positions: (1) forward or feed, (2) neutral, and (3) reverse. Mechanical feed control bars, until now, have been configured only to take advantage of these three positions. An implication of this is that, if the feed mechanism becomes plugged or the chipper bogs down due to a greater feed rate than permissible, the operator must carefully find neutral, then reverse. Usually, neutral is centered between forward and reverse, as this is the way the hydraulic control valve is typically arranged. 
   An electrically controlled brush chipper is disclosed in U.S. Patent application No. 2004/0108397 entitled  Improved Brush Chipper and methods of Operating Same  by O&#39;Halloran et al., filed Dec. 1, 2003 and is hereby incorporated by reference. In the disclosed approach, a plurality of operating modes is disclosed using the versatility of electrical/electronic controls. 
   U.S. Pat. No. 5,692,548 by Bouwers et al. and U.S. Pat. No. 5,692,549 by Eggers are hereby incorporated by reference and disclose brush chippers having many components of the brush chippers on which the present invention is used. Some of the pertinent components are: a material inlet, or feed table assembly, a plurality of feed rollers, and a chipping drum. The feed rollers are driven by hydraulic motors. No control system for the feed rollers is disclosed. 
   There is, therefore, a need for a method and apparatus for a mechanical feed control bar providing four positions wherein the extreme positions are stop and reverse. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object of the present invention is to provide a stop position, in addition to the usual forward (or feed), neutral, and reverse positions. 
   Still another object of the present invention is to provide a stop function to the mechanical feed control bar wherein, when the feed control bar is in its stop position, another lever must be manually manipulated in order to return the feed mechanism to a forward feed. This prevents prematurely feeding material into the chipper before the problem has been fully remedied. 
   To accomplish the above objects, the feed control assembly comprises an upper feed control bar, a feed control cam, a feed control linkage, a stop cam and an actuator cam. The feed control assembly provides for four individual, distinct positions for the upper feed control bar. In the forward feed, neutral, and stop positions, the upper feed control bar is held in place by a spring loaded roller and notches in the feed control and stop cams. In the reverse position, the upper feed control bar is not held in place by the feed control assembly. Rather, the operator must provide a continuous force to the upper feed control bar as long as reverse action is desired. Nonetheless, the reverse position is a distinct, individual position for the upper feed control bar. 
   The stop cam has detents for two individual positions, defining the mode of the stop cam: normal or stopped. 
   A first end of the feed control linkage is pivotally attached to the upper feed control bar while a second end is pivotally attached to the feed control cam so that manipulation of the feed control bar directly influences the position of the feed control cam. Additionally, the upper feed control bar connects with the stop cam via a stop linkage through the actuator cam. The positions of the stop cam and the feed control cam define the four distinct positions of the feed control bar. 
   Between the first and second ends of the feed control linkage and attached thereto is a support structure to which the actuator cam is pivotally attached. From a first side of the actuator cam, a first linkage runs to the hydraulic control valve. Approximately opposite the first side, a second linkage runs from the actuator cam to the stop cam. The second linkage engages the actuator cam in such a fashion as to permit the actuator cam to apply a tension force to the second linkage, but not a compressive force. 
   During normal operation, the force applied to the actuator cam by the linkage to the stop cam causes the actuator cam to rotate as the feed control bar is moved from the neutral to the forward feed position. The rotation of the actuator cam is necessary for sufficient actuation of the hydraulic control valve into its forward position. When the feed control bar is pulled beyond the forward feed position, the stop cam is drawn out of the detent position holding it in place, and the second linkage slides back through the aperture in the actuator cam in which it resides. Without the tension force on the second linkage, the actuator cam cannot rotate sufficiently to actuate the hydraulic valve into its forward feed position. However, the actuator cam does not need to rotate to actuate the hydraulic valve into its reverse position. Therefore, even in the stopped mode, the feed mechanism can be reversed. 
   In the stopped mode, the stop cam is in a stop position, holding the second linkage in such a position as to disallow any forces being applied to it by the actuator cam. The stop cam must be returned to its run position before the feed mechanism can be returned to a forward feed mode. To effect the return of the stop cam to its run position, a reset handle is manually manipulated, effectively rotating the stop cam back to its run detent position by a third linkage operatively engaged by the reset handle and pivotally attached to the stop cam. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a brush chipper showing the feed control assembly of the present invention; 
       FIG. 2  is a first perspective view of a rear portion of the brush chipper; 
       FIG. 3  is a second perspective view of a rear portion of the brush chipper; 
       FIG. 4  is a first perspective view of a mechanical feed control assembly for the brush chipper; 
       FIG. 5  is a second perspective view of a mechanical feed control assembly for the brush chipper; 
       FIG. 6   a  is a side elevation view of an upper feed control bar in a plurality of positions; 
       FIG. 6   b  is a side elevation view of the feed control assembly with the upper feed control bar in a forward mode and the stop cam in run mode; 
       FIG. 6   c  is a side elevation view of the feed control assembly with the upper feed control bar in a neutral mode and the stop cam in run mode; 
       FIG. 6   d  is a side elevation view of the feed control assembly with the upper feed control bar in a reverse mode and the stop cam in run mode; 
       FIG. 6   e  is a side elevation view of the feed control assembly with the upper feed control bar in a reverse mode and the stop cam in stop mode; 
       FIG. 6   f  is a side elevation view of the feed control assembly with the upper feed control bar in a neutral mode and the stop cam in stop mode; 
       FIG. 6   g  is a side elevation view of the feed control assembly with the upper feed control bar in a forward mode and the stop cam in stop mode; 
       FIG. 6   h  is a side elevation view of the feed control assembly with the upper feed control bar in a stop mode and the stop cam in stop mode; 
       FIG. 7  is a detail of an actuator cam; 
       FIG. 8  is a perspective view of the rear portion of the chipper with the feed control assembly in reverse; 
       FIG. 9  is a side elevation view of the rear portion of the chipper with the feed control assembly in reverse; 
       FIG. 10  is a perspective view of the rear portion of the chipper with the feed control assembly in neutral; 
       FIG. 11  is a side elevation view of the rear portion of the chipper with the feed control assembly in neutral; 
       FIG. 12  is a perspective view of the rear portion of the chipper with the feed control assembly in forward; 
       FIG. 13  is a side elevation view of the rear portion of the chipper with the feed control assembly in forward; 
       FIG. 14  is a perspective view of the rear portion of the chipper with the feed control assembly in a stop position; and 
       FIG. 15  is a side elevation view of the rear portion of the chipper with the feed control assembly in a stop position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   For the purposes of this document, the term mechanical control is defined as a control system wherein actuation is due to a mechanical linkage from the control bar to the hydraulic control valve. No electrical actuation is incorporated. Of course merely adding electrical components to the mechanical system of the present invention can be done and still be within the scope and spirit of the present invention. 
   A brush chipper  10  is shown in  FIG. 1 . The direction of brush feeding is generally controlled through the manipulation of the feed control assembly  100  via the upper feed control bar  110 . Generally, the brush chipper comprises a feed table assembly  120 , ground engaging wheels  130  (only one seen in  FIG. 1 ), and a conveyance for chipped matter, in this case a chute  140 . Not seen in  FIG. 1  are a plurality of feed rollers driven by hydraulic motors, and at least one cutter drum or cutter disk. 
   The brush chipper  10  of  FIG. 1  has a front, generally toward the tongue  150 , and a rear, generally toward the feed table assembly  120 . In keeping with these definitions, the forward direction is defined as toward the front of the chipper, while the backward or rearward direction is defined as toward the rear of the chipper. These terms are hereby defined and will be used as above throughout this document, including the claims. 
   A rear portion of the brush chipper  10 , including the feed table assembly  120 , is shown in  FIGS. 2 and 3 . The upper feed control bar  110  is clearly seen. A first end of a feed control linkage  205  is pivotally attached to the upper feed control bar  110  while a second end of the feed control linkage  205  is pivotally attached to a feed control cam  215  so that manipulation of the feed control bar  110  directly influences the position of the feed control cam  215 . Combined, the feed control cam  215  and the stop cam  245 , define four individual, distinct positions of the upper feed control bar  110 . 
   Between the first and second ends of the feed control linkage  205  and attached to the feed control linkage  205  is a support structure  220  to which an actuator cam  225 , best seen in  FIG. 4 , is pivotally attached. From a first side of the actuator cam  225 , a valve linkage  230 , best viewed in  FIGS. 3 and 4 , runs to the hydraulic control valve  235  which is a spring-centered hydraulic control valve  235 . Approximately opposite the first side of the actuator cam  225 , a stop linkage  240  runs from the actuator cam  225  to a stop cam  245  (see also  FIG. 5 ). The stop linkage  240  engages the actuator cam  225  in such a fashion as to permit the actuator cam  225  to apply a tension force to the stop linkage  240 , but not a compressive force. This is effected by permitting the stop linkage  240  to slide rearward through an aperture in a bracket  250  integral with, or affixed to, the actuator cam  225  when the feed control assembly  100  is set to its stop position. 
   During normal operation, the force applied to the actuator cam  225  by the stop linkage  240  causes the actuator cam  225  to rotate as the feed control bar  110  is moved from a neutral position to a forward feed position. The rotation of the actuator cam  225  is necessary for sufficient actuation of the hydraulic control valve  235 . When the feed control bar  110  is pulled rearward, beyond the forward feed position, the stop cam  245  is drawn out of its detent position where it was held in place, and the stop linkage  240  slides rearward through the aperture in the bracket  250  of the actuator cam  225  in which it resides. Without the tension force on the stop linkage  240 , the actuator cam  225  does not rotate sufficiently to actuate the hydraulic control valve  235  to its forward feed position. However, the actuator cam  225  does not need to rotate to actuate the hydraulic control valve  235  into its reverse position. Therefore, even in the stopped mode, the brush chipper feed mechanism  100  can be reversed by an operator. 
   In the stopped mode, the stop cam  245  is in a stop position, holding the stop linkage  240  in such a position as to disallow any forces being applied to the stop cam  245  by the actuator cam  225  via the stop linkage  240 . The stop cam  245  must be returned to its run position before the feed mechanism can be returned to a forward feed mode. To effect the return of the stop cam  245  to its run position, a reset handle  160  is manually manipulated, effectively rotating the stop cam back to its run position by a third linkage operatively engaged by the reset handle and pivotally attached to the stop cam. 
   A lower feed control bar  210  is also seen in  FIG. 2 . Manipulation of the lower feed control bar  210  shifts the feed control assembly  100  into the stop mode. When the lower feed control bar  210  is moved forward, pivoting on its axis of rotation  270 , a lower feed bar linkage  275  is drawn rearward tripping the reset handles  160  via a trip lever  280 . 
   The four positions of the upper feed control bar  110  are shown in  FIGS. 8-15 . In  FIG. 6   a , the upper feed control bar is shown alone in its four (4) positions:
         1. Stop   2. Forward   3. Neutral   4. Reverse
 
in order from rearmost to front-most. This order represents the preferred embodiment, but the present invention is not limited thereto. An advantage of the present invention is that the extreme positions of the upper feed control bar  110 , both front and back, are positions that either stop or reverse the feed rollers.
       

     FIGS. 6   b - 6   h  show the seven combinations of the feed control cam  215  and the stop cam  245 . The brush chipper  10  operates in a forward-feed, or normal operating mode when the feed control assembly  100  is as shown in  FIG. 6   b . The stop cam  245  is in its run position, while the feed control cam  215  is in its forward position. The feed control cam  215  is kept from rotating by the spring-loaded cam roller  600  and the shape of the feed control cam  215 . The combination of the feed control cam  215  and stop cam  245  positions results in the hydraulic control valve  235  being positioned in its forward feed position. 
   In  FIG. 6   c , the brush chipper  10  is in its neutral mode. The stop cam  245  is in its run position, while the feed control cam  215  is held in its neutral position by the spring-loaded cam roller  600 . Therefore, the hydraulic control valve  235  is positioned in its neutral position. In the configuration of  FIG. 6   c , the operating mode of the brush chipper  10  may be changed simply by changing the position of the upper feed control bar  110 . 
   The brush chipper  10  operates in a reverse-feed mode when the feed control assembly  100  is as shown in  FIG. 6   d . The stop cam  245  is in its run position, while the feed control cam  215  is held in its reverse position by the spring-loaded cam roller  600 . Therefore, the hydraulic control valve  235  is positioned in its reverse feed position. In this reverse position, the operator must hold the upper feed control bar  110  in place as long as reverse feed is desired. 
   In  FIG. 6   e , the feed control cam  215  is shown in its reverse position while the stop cam  245  is in its stop position. Despite the stop cam  245  being in its stop position, in this configuration, the brush chipper feed mechanism operates in reverse, as indicated by the hydraulic control valve&#39;s  235  position. As above, the feed control cam  215  is held in position by the spring-loaded cam roller  600 . 
   In  FIG. 6   f , the upper feed control bar  110  is shown in its neutral position while the stop cam  245  is in its stop position. No feed is provided to the feed mechanism of the brush chipper  10 . The feed control cam  215  is held in position by the spring-loaded cam roller  600 . 
   In  FIG. 6   g , the upper feed control bar  110  is shown in its forward position while the stop cam  245  is in its stop position. Despite the upper feed control bar  110  being in its forward position in this configuration, no feed is provided to the brush chipper&#39;s feed mechanism, as indicated by the hydraulic control valve&#39;s  235  position. The feed control cam  215  is held in position by the spring-loaded cam roller  600 . 
   In  FIG. 6   h , the upper feed control bar  110  is shown in its stop position while the stop cam  245  is in its stop position. This is the emergency stop mode for the brush chipper  10 , and no feed is provided to the brush chipper&#39;s feed mechanism, as indicated by the hydraulic control valve&#39;s  235  position. The feed control cam  215  is held in position by the spring-loaded cam roller  600 . 
   In the reverse position shown in  FIGS. 8 and 9 , the upper feed control bar  110  is pushed to its front-most position. The compression force on the valve linkage  230  tends to rotate the actuator cam  225  in a counterclockwise direction (from above as seen in  FIG. 8 ) until an end of the arcuate slot  710  shown in  FIG. 7  engages a bolt  810 . The actuator cam  225  is then able to apply an adequate compressive force to the valve linkage  230  to actuate the hydraulic control valve  235 . The stop linkage  240  is free to slide through the bracket  250 . The reset handles  160  are in their rearmost, or operating, position. 
   The position just rearward from the reverse position of the upper feed control bar  110  is the neutral position and is illustrated in  FIGS. 10 and 11 . In this position, there is no significant force on the valve linkage  230 . The bolt  810  needs not bear against nor apply a force to the end of the arcuate slot  710  in the actuator cam  225 . The stop linkage  240  is still slid through the bracket  250 , so it cannot apply a force to the actuator cam  225 . Because the hydraulic control valve  235  is spring-centered, the lack of force on the hydraulic control valve&#39;s lever  1010  results in its return to center, which is the neutral position. The reset handles  160  remain in their rearmost, or operating, position. 
   Immediately rearward from the neutral position, the upper feed control bar  110  is in its forward or feed position as illustrated in  FIGS. 12 and 13 . The stop linkage  240  has now engaged the bracket  250  on the actuator cam  225  and applies a first force to the actuator cam  225  tending to rotate the actuator cam  225  in a counterclockwise direction as viewed from the top. The first force counteracts a second force applied by the valve linkage  230  to the actuator cam  225 . The result is the actuation of the hydraulic control valve&#39;s lever  1010  in a rearward direction, which provides a forward feed to the brush feed mechanism. The reset handles  160  remain in their rearmost, or operating, position. 
   The stop position is the extreme rearward position of the upper feed control bar  110 . In this position, the feed control cam  215  is not held in position by a detent. The valve linkage  230  applies a force to the actuator cam  225  tending to rotate the actuator cam  225  in a clockwise direction as viewed from above. As the upper feed control bar  110  is pulled back, the hydraulic control valve&#39;s lever  1010  reaches its rearmost position, beyond which it cannot travel. Therefore, the force applied to the actuator cam  225  by the valve linkage  230  is significant. This force is somewhat countered by the stop linkage  240 . However, the valve linkage  230  applies the greater force, and the stop cam  245  is rotated out of its detent position, permitting the actuator cam  225  to rotate clockwise (as seen from the top as in  FIG. 14 ) under the force of the valve linkage  230 . The stop cam  245  is rotated such that the stop linkage  240  travels rearward, sliding through the bracket  250  of the actuator cam  225 . With the stop linkage  240  unable to apply a force to the bracket  250 , the actuator cam  225  is free to rotate. The only source of force to the actuator cam  225 , other than friction, is from the valve linkage  230 . However, the actuator cam  225  cannot support a force because it rotates freely. Hence, the hydraulic control valve lever  1010  will return to the center or neutral position because the hydraulic control valve  235  is spring-centered. 
   The reset handles  160  have been tripped into their front-most, or tripped, position in  FIGS. 14 and 15 . Returning to  FIG. 2 , a trip linkage  285  is pivotally connected to the stop cam  245 . In turn, the trip linkage is pivotally attached to a bumper  290  which is connected to an angle member  295  affixed to the two reset handles  160 . When the trip linkage  285  is drawn forward due to the stop cam  245  being rotated out of its detent, the bumper  290  is also drawn forward along with the angle member  295  connected to the reset handles  160 . Manually drawing the reset handles  160  back resets the stop cam  245  and readies the feed control assembly  100  for normal service. 
   Another aspect of the present invention is a safety measure when the brush chipper  10  is readied up for transport. The feed table assembly  120  is folded up from the rear and contacts the bumper  290  which forces the trip linkage  285  forward and rotates the stop cam  245  out of its detent. This puts the feed control assembly  100  into its stop position, disallowing brush or anything else to be fed into the brush chipper&#39;s  10  cutters by the feed rollers. 
   The above embodiment is the preferred embodiment, but this invention is not limited thereto. It is, therefore, apparent that many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.