Safety device for brush chipper

A brush chipper having a guard (38) which is released to block the inlet (12) to the cutter (10) when an emergency condition is sensed. During normal operation of the chipper, the guard (38) is held out of the path of brush to the cutter (10). When a weight, in excess of a normal brush load, is sensed, as for example when the chipper operator is being drawn into the chipper, the guard (38) is released automatically and moves to block the inlet (12) to the cutter (10). This prevents the operator from being drawn into the cutter (10).

DESCRIPTION 
Technical Field 
The present invention relates, in general, to brush chippers which reduce 
the volume of the branches and similar debris by cutting the brush into 
small chips and, in particular, to brush chippers provided with a safety 
device which prevents an operator of the chipper from being pulled into 
the cutter portion of the chipper. 
Background Art 
As a result of various tree pruning, land clearing and similar operations, 
tree limbs and similar debris referred to as brush are provided and should 
be reduced in volume to facilitate its handling and disposal. At the 
present time, brush chippers are utilized to cut the brush into small 
chips which can be deposited in an easily handled pile and utilized for 
natural recycling as mulch or ground cover or which can be utilized for 
pulp in making paper. One type of brush chipper which has been effectively 
used includes a housing having an inlet opening and an outlet opening in 
communication with a discharge chute. Carried in the housing is a cutter 
bar and a rotor assembly including a plurality of cutting blades which 
cooperate with the cutter bar for cutting brush fed through the inlet 
opening into small chips and for discharging the chips through the outlet 
opening into the discharge chute. A blower is usually associated with the 
discharge chute for facilitating the convevance of chips through the 
chute. U.S. Pat. No. 3,944,147 illustrates a brush chipper of the type 
just described. 
Safety for the operator of a brush chipper is a major concern. Besides the 
hazards which might be attributable to the carelessness of the operator, 
there are some which occur through no real fault on the part of anyone. 
For example, a tree limb having many branches may catch on the belt or 
belt loop of the operator and drag the operator into the cutter portion of 
the chipper. The present invention is directed to protecting the operator 
whether the hazard is caused by his carelessness or by an incident far 
more difficult to anticipate. 
For the most part, efforts in the past to provide safety features in brush 
chippers have involved manually operated brake mechanisms. These units 
have been designed in such a way that an operator, exposed to an emergency 
condition, manually actuates a brake as he is being dragged toward the 
cutter. Generally, these prior attempts have suffered from three 
shortcomings. First, the safety feature is not positive in the sense that 
it requires shut-down of the cutter rather than prevention of the operator 
reaching the cutter. Second, by requiring manual actuation, in a hazard 
situation, there is the possibility that an operator is so preoccupied 
with his safety that he may not actuate the brake mechanism in time. 
Third, because the cutting function requires massive cutter members, the 
inertia of the cutter members either prevents quick enough stopping or 
causes damage or destruction of various components, such as the drive 
shaft of the chipper, when the brake mechanism is actuated. Furthermore, 
operators of brush chippers having manually actuated emergency brakes tend 
to use the emergency shut-down feature by actuating the brake mechanism, 
rather than the normal shut-off switch, because normal shut-down may take 
as long as ten minutes due to the inertia of the cutters members. This 
results in undue exposure of various components of the chipper to damage 
and destruction. 
DISCLOSURE OF INVENTION 
Accordingly, it is an object of the invention to provide a new and improved 
brush chipper. 
It is another object of the present invention to provide a brush chipper 
having a safety device which is effective in preventing an operator of the 
chipper from being dragged into the cutter of the chipper. 
It is yet another object of the present invention to provide a brush 
chipper which is relatively simple in construction. 
It is a further object of the present invention to provide a brush chipper 
which may be fabricated at reasonable cost. 
A brush chipper, constructed in accordance with the present invention, 
includes a cutter housing and cutting means within the housing for cutting 
brush into small chips. Brush to be chipped is supplied to the cutting 
means from feed means which communicate with the cutter housing through an 
inlet opening. Chips are carried away from the cutting means through 
discharge means which communicate with the cutter housing through an 
outlet opening. Also included in the brush chipper are guard means movably 
mounted forward of the cutting means for obstructing the supply of brush 
to the cutting means during an emergency condition. The guard means are 
movable between a normal position at which the supply of brush to the 
cutting means is unobstructed and an emergency position within the path of 
movement of the brush to the cutting means to obstruct the supply of 
brush. The brush chipper further includes control means coupled to the 
guard means for holding the guard means in its normal position and, upon 
actuation, for releasing the guard means to permit movement to the 
emergency position.

BEST MODE OF CARRYING OUT THE INVENTION 
U.S. Pat. No. 3,944,147 is incorporated herein by reference to supplement 
the disclosure of various components of a brush chipper which do not form 
part of the present invention. 
Referring to FIGS. 1 and 3, a brush chipper constructed in accordance with 
the present invention includes a cutter housing 10 having an inlet opening 
12 and an outlet opening 14. Located within cutter housing 10 are cutting 
means for cutting brush, fed through inlet opening 12, into small chips. 
The cutting means may include a rotor 16 carried on a shaft 18 centrally 
located within housing 10 and extending through the end walls thereof. One 
end of shaft 18 fixedly carries a sheave 20 to which drive is imparted to 
turn rotor 16. Secured to the rotor are a plurality of cutting blades 22. 
Additional details about the cutting means and the apparatus for driving 
the cutting means may be obtained from U.S. Pat. No. 3,944,147. 
The brush chipper of the present invention also includes feed means 
communicating with the housing 10 through inlet opening 12 for supplying 
brush to the cutting means. The feed means may include a feed chute 24 and 
a feed table 26 over which brush is supplied. Feed table 26 has side walls 
26a. During normal operation of the brush chipper, feed table 26, in 
effect, is an extension of chute 24 and serves to funnel brush into the 
chute. 
As best seen in FIG. 1, the feed table is mounted for movement between a 
normal position, illustrated in FIG. 1, at which a normal load of brush 
has been deposited on the table and an emergency position at which a 
weight in excess of a normal load of brush has been deposited on the 
table. Feed table 26 is mounted for pivotal movement about a rod 30 which 
is held in place by a pair of brackets 32 secured to the bottom of chute 
24 and near its sidewalls. The feed table is secured to a pair of bushings 
34 which are mounted for rotational movement about rod 30. As weight is 
applied to feed table 26, it tends to rotate clockwise, as viewed in FIG. 
1, about rod 30. 
The brush chipper, constructed in accordance with the present invention, 
further includes discharge means communicating with housing 10 through 
outlet opening 14 for carrying away chips from the cutting means. The 
discharge means may include a discharge chute 36 extending upwardly and 
away from outlet opening 14 for conveying chips, discharged by the cutter, 
to an appropriate storage device. If, as is usual, the brush chipper is 
mounted on a trailer hitched to a truck, the storage device is the 
enclosed bed of the truck. FIGS. 1 and 2 illustrate the brush chipper 
mounted on a trailer. Additional details about the mounting of the chipper 
may be obtained from U.S. Pat. No. 3,994,147. 
The brush chipper of the present invention also includes guard means 
movably mounted forward of the cutting means for obstructing the supply of 
brush to the cutting means during an emergency condition. For the 
embodiment of the invention illustrated, such means include a plate 38 
shaped and sized approximately equal to inlet opening 12. Plate 38 is 
pivotally movable about a rod 40 between a normal position, shown in solid 
lines in FIG. 1 and dotted lines in FIG. 4, at which the plate does not 
obstruct the supply of brush to the cutting means, and an emergency 
position, shown in solid lines in FIG. 2 and dotted lines in FIGS. 1 and 
3, within the path of movement of the brush to the cutting means to 
obstruct the supply of brush to the cutting means. Rod 40, the pivot for 
plate 38, is secured along the top edge of inlet opening 12. In its normal 
position, plate 38 is held adjacent the top surface of chute 24 by means 
which will be described shortly. During an emergency condition, plate 38 
is released to permit movement to the emergency position. This movement, 
clockwise as viewed in FIG. 1, is in the direction of movement of the 
brush from feed table 26 and feed chute 24 to the cutting means. This 
arrangement causes plate 38 to be drawn with the brush toward the cutting 
means as the brush is being drawn by the cutting means and, thereby, close 
off inlet opening 12. The plate moves with the brush until the brush 
becomes wedged between the bottom edge of the plate and the bottom surface 
of chute 24. The final position of plate 38 is determined by the size of 
the brush wedged between the plate and chute 24. By limiting the use of 
the chipper to the brush for which it is intended, plate 38 will drop to 
either the absolute vertical position shown dotted in FIGS. 1 and 3 or to 
a position very close to the vertical. In order to enhance the engagement 
of the bottom edge of plate 38 and the brush, the bottom edge of the plate 
preferably is toothed as shown in FIG. 2. Double-ended arrow 42 indicates 
the bi-directional movement of plate 38 to the emergency position when an 
emergency condition exits and to the normal position when the plate is set 
for normal cutting and chipping. 
The brush chipper, constructed in accordance with the present invention, 
further includes control means coupled to the guard means for holding the 
guard means in the normal position and, upon actuation, for releasing the 
guard means to permit movement of the guard means to the emergency 
position. For the embodiment of the invention illustrated in the drawings, 
the control means include a rod assembly having a rod 44, a plate 46 
carried at one end of rod 44 and a pin 48 carried by plate 46. The rod 
assembly is movable between a first position at which pin 48 engage a lug 
50 which is secured to the back of plate 38 and extends through an opening 
in chute 24 and a second position at which pin 48 is disengaged from lug 
50. Such movement is represented in FIG. 1 by a double-ended arrow 51 and 
showing plate 46 dotted in its second position at which pin 48 is 
disengaged from lug 50 and plate 38 is released and permitted to move into 
its emergency position. 
Rod 44 is movable along its axis through openings in a pair of posts 52 and 
54. A spring 56, in the form of a coil spring, surrounds rod 44 and urges 
the rod to its first position at which pin 48 engages lug 50. 
Specifically, spring 56 is in compression between post 54 and a plate 58 
secured to rod 44. With such a spring bias, rod 44 is urged to its first 
position at which plate 58 abuts post 52. The location of plate 58 
relative to post 52 in FIG. 3 represents the rod assembly in its second 
position. Such movement occurs when a force is applied to rod 44 adequate 
to cause further compression of spring 56. The spring is designed to 
undergo this further compression when a force slightly in excess of the 
weight of a normal load of brush is applied to rod 44. 
The end of rod 44 opposite from the end which carries plate 46 and pin 48 
is pivotally pinned to a bracket 60 which, in turn, is secured to a frame 
member 62. The frame member is pivotally secured at its ends to a pair of 
pivot arms 63 and a pair of brackets 64 at the sidewalls of chute 24. 
Pivot arms 63 pivot about pins 65 and brackets 64 pivot about pins 66 
which are the pins by which pivot arms 63 and brackets 64 are secured to 
frame member 62. Each of the brackets 64 has a return bend 64a into which 
is fitted an extension 68 of feed table 26. 
When a weight, in excess of a normal load of brush, is deposited on feed 
table 26, for example when an operator of the brush chipper becomes 
entangled in the brush and is drawn by the brush onto the feed table, the 
table pivots clockwise about rod 30, in turn, causing extensions 68 to 
move brackets 64 and pivot arms 63 to the positions shown in dotted lines 
in FIG. 1. This moves frame member 62 away from post 54 and moves rod 44, 
against the action of spring 56, to disengage pin 48 from lug 50. Plate 38 
now is free to drop from its normal position adjacent the top surface of 
chute 24 to its emergency position blocking inlet opening 12. 
Although the cutter continues to rotate after plate 38 has dropped to its 
emergency position and the bursh has been wedged between the plate and 
chute 24, the operator is protected in two ways. First, with the brush no 
longer being drawn toward the cutter, the operator is no longer drawn 
toward the cutter. Second, with plate 38 blocking inlet opening 12, the 
plate serves to prevent any part of the operator's body from coming into 
contact with the cutter. 
While in the foregoing there has been described a preferred embodiment of 
the invention, it should be understood to those skilled in the art that 
various modifications and changes can be made without departing from the 
true spirit and scope of the invention as recited in the claims.