Feed rollers for chipper

A chipper for chipping wood material has first and second feed rollers at an inlet. The first and second feed rollers are secured to a frame of the chipper with the axes of the feed rollers being parallel and spaced apart. The first and second feed rollers are free to move in a direction generally transverse to the axes. The feed rollers are biased toward one another. A motor drives at least one of the feed rollers to rotate the feed roller about its axis of rotation.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention pertains to wood chippers, and more particularly to wood 
chippers having rollers for feeding wood material to a chipper member. 
2. Description of the Prior Art 
Wood chippers are well known to reduce trees, limbs, branches, bushes and 
the like, to wood chips. Chippers come in a wide variety of sizes and 
power ratings to handle wood material of varying sizes. 
In so-called "drum-type" chippers, the chipper includes a cylindrical drum 
which carries knives or blades on a circumferential wall of the drum. The 
drum is driven to rotate about a cylindrical axis at high velocities. As 
wood material is urged toward the cylindrical drum, the knives chip away 
at the wood material. An example of a drum chipper is shown in U.S. Pat. 
No. 5,005,620 to Morey, dated Apr. 9, 1991. 
An additional type of wood chipper is a so-called "disc-type" chipper where 
cutting knives are carried radially on the face of a spinning disc. An 
example of a disc chipper is illustrated in U.S. Pat. No. 3,861,602 to 
Smith, dated Jan. 21, 1975. 
In both drum-type and disc-type chippers, the chipper will include an inlet 
and an outlet. At the inlet, rollers are commonly provided to feed a log 
or wood material toward the knives. The outlet typically includes a 
discharge chute to receive chips and direct the chips in a controlled 
direction so that the chips may be accumulated for subsequent disposal. 
Where a chipper includes an inlet having rollers or the like for advancing 
wood material towards the chipper, commonly two rollers are used. Each 
roller is mounted with cylindrical axes of the rollers being parallel. One 
roller is commonly fixed in location and the other roller may be fixed or 
may be movable toward the fixed roller. With such designs, it has been 
found that wood material (such as a log) can be admitted into the inlet of 
the chipper with the longitudinal axis of the log being out of alignment 
with a path of travel from the rollers to the chipper member. As a 
consequence of this misalignment, wood material may not be fed towards the 
chipper member in the most efficient direction. More seriously, when the 
misaligned wood material engages the chipper member, the dynamics of the 
chipper member may cause the misaligned wood member to be moved into a 
more direct line of travel. This realignment of the wood material can 
cause a free end of the wood material which is exterior of the inlet to 
the chipper to be moved to the side. If an operator were to be in the 
vicinity, the wood material (which may be a log of substantial diameter) 
may knock into the operator. 
It is an object of the present invention to provide a chipper where the 
feed rollers may float to accommodate possible misalignment of material 
being fed into the chipper. 
SUMMARY OF THE INVENTION 
According to a preferred embodiment of the present invention, a chipper for 
chipping wood material has a frame with a chipping member (such as a drum) 
carried on the frame. The frame has a material inlet for feeding material 
to be chipped to the chipping member. The material inlet includes two feed 
rollers. The feed rollers are secured to the frame with the axes of the 
feed rollers in generally parallel alignment. Each of the feed rollers is 
movable toward and away from each other along a path of travel which is 
generally transverse to the axes. A biasing spring urges the first and 
second feed rollers to move toward each other along the path of travel. At 
least one of the rollers is provided with a motor to rotate the roller 
about its axis of rotation.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the several drawing figures in which identical elements 
are numbered identically throughout, a description of the preferred 
embodiment to the present invention will now be provided. 
With initial reference to FIG. 1, a chipper 10 is shown including a frame 
12 having an inlet end 14 and a discharge chute 16. Positioned between the 
inlet end 14 and the discharge chute 16 is a rotating drum 18 mounted to 
rotate about a cylindrical axis X--X. The drum 18 is provided with blades 
20 on its circumferential wall. 
An engine 21 is mounted on the frame 12 and is coupled to the drum 18 by a 
belt 22. The engine 21 rotates the drum 18 about its axis X--X. 
In a preferred embodiment, the chipper 10 is shown as being a drum-type 
chipper containing a cylindrical drum 18 with blades 20 on its 
circumferential wall. This example is given for purposes of illustration. 
It will be appreciated that the present invention is applicable to other 
types of chipper members including so-called disc-type chippers. 
In operation, wood material is admitted by an operator into the inlet end 
14 and fed toward the rotating drum 18. The blades 20 chip away at the 
wood material with produced chips being discharged through the discharge 
chute 16 for subsequent disposal. 
With reference now to FIG. 2, the inlet end 14 of the chipper 12 is shown 
and includes two feed rollers 24, 26. Roller 26 is mounted to the frame 12 
for the roller 26 to rotate about its cylindrical axis Y--Y. Similarly, 
roller 24 is mounted to the frame 12 to rotate about its cylindrical axis 
Z--Z. 
Each of the rollers 24, 26 is provided with axially extending ribs 28 on 
the circumferential face of the rollers 24, 26. The ribs 28 will engage 
wood material to grip the wood material and advance it toward the drum 18. 
The entrance 14 may be provided with a curtain 30 to restrict admission of 
material towards the rollers 24, 26 when the chipper is not in use and to 
prevent an operator from inadvertently contacting the rollers 24, 26. The 
curtain 30 also blocks chips that might be deflected out the rear of the 
apparatus 10. Each of the rollers 24, 26 is provided with a hydraulic 
motor 30, 32 for rotating the rollers 24, 26 about their axes. 
As will be described, the rollers 24, 26 are free floating in that the 
rollers 24, 26 can be moved toward and away from each other along a path 
of travel (A) which is transverse to the axes Y--Y and Z--Z. 
With reference to FIG. 4, the assembly of roller 26 is illustrated. It will 
be appreciated that the assembly of roller 24 is identical. 
As illustrated in FIG. 4, motor 32 is connected to a shaft 38 by a key 40. 
The shaft 38 extends through a sleeve 42 with the motor 32 being secured 
to the sleeve 42 by means of bolts 44 received in bolt holes 46. The shaft 
38 is freely rotating within sleeve 42 and is supported therein by a 
bearing 46 contained within sleeve 42. The sleeve 42 carries a snap ring 
48 to retain bearing 46. 
The roller 26 includes a top plate 26a and a bottom plate 26b. The top 
plate 26a includes an axially centered hub 50 for passing the shaft 38. 
Further, the bottom 26b includes an axially aligned hub 52 which also 
passes the shaft 38. A tapered hub 54 is provided to be received within 
hub 52 and to be secured to the shaft 38 for rotation therewith by means 
of a key 56. The tapered hub 54 is secured to hub 52 by means of bolts 58 
received within bolt holes 60. Accordingly, when assembled as described, 
the drum 26 rotates by means of the motor 32 rotating shaft 38 which, in 
turn rotates tapered hub 54 which is secured to the roller 26. 
The inlet 14 is provided with a floor 62. The floor 62 may, again a 
preferred embodiment, have an access opening permitting a mechanic to have 
access to bolts 58. The access opening may be covered by a plate 64 
secured to the floor 62 by means of nuts 66 received on threaded studs 68. 
Referring back FIG. 2, the inlet 14 is provided with a top wall 70 which is 
generally parallel to the bottom wall 62. The top wall 70 is provided with 
a slot 72 (FIG. 3) extending transversely across the width of the chipper 
inlet 14. 
Shown in FIG. 4, sleeve 42 is provided with a plate 74 wider than slot 72 
such that the plate 74 may rest on top wall 70 and not pass through slot 
72. Accordingly, the plates 74 support the rollers 26, 24 and keep the 
rollers from contacting the floor 62 of the inlet. 
Side edges of the plate 74 are provided with low friction slide blocks 76, 
which slide on plate 70 on opposite sides of slot 72. Top plates 80 are 
secured to the top wall 70 by bolts 82 received within spacer blocks 84. 
The spacer blocks 84 maintain the top plates 80 in parallel-spaced apart 
alignment to the top wall 70 and spaced from top wall 70 by a distance 
slightly greater than the thickness of the slide blocks 76. Accordingly, 
the slide blocks 76 are captured between the top plates 80 and the top 
wall 70 with the slide blocks 76 permitting sliding movement of the sleeve 
42 in the direction A illustrated in FIGS. 2 and 3. 
The sleeves 42 are provided with upwardly extending plates 88. Springs 90 
are connected to the plates 88 on opposite sides of the motors 30, 32 with 
the springs 90, urging the slides 42 toward one another in the direction 
A. 
In a preferred embodiment, the motors 30, 32 are hydraulic motors. 
Hydraulic fluid is admitted to a manifold 100 (FIG. 3) via inlet and 
exhaust lines 102, 104. The manifold 100 distributes the hydraulic fluid 
into secondary inlet and exhaust lines 106, 108 which feed the motors 30, 
32. 
With the construction thus described, it will be appreciated that the feed 
rollers 24, 26 are rotated by motors 30, 32 to advance wood material 
towards the chipper member 18. The rollers 24, 26 may be spread apart to 
accommodate large or small diameter logs or other volumes of wood material 
to be chipped. Furthermore, both rollers may float to either the right or 
the left (in the view of FIG. 2) to accommodate a log or other material to 
be chipped which is fed out of alignment with the direction of the path to 
the chipper member. This operation is illustrated in FIGS. 5 through 8. 
In FIG. 5, a large diameter log 200 is shown being longitudinally aligned 
with the center C of the chipper member and with the rollers 24, 26 spread 
apart to accommodate the size of the large log 200 in equal distance from 
the center C. The spring 90 urges the rollers 24, 26 against the log 200. 
In FIG. 6, a smaller diameter log 202 is shown with log 202 also being 
directly aligned with the center C of the chipper member. The spring 90, 
maintains the rollers 24, 26 snugly against the log 202. 
In the event a log is fed into the inlet 14 at an angle such that it is not 
already properly aligned with the center C of the inlet, instead of 
forcing the log into alignment, the novel roller system realigns the 
positioning of the rollers 24, 26. This is shown in FIG. 7 where a large 
diameter log 200' has been fed such that it is out of alignment with the 
center C of the inlet. Rather than forcing the log 200' into alignment 
with this center C, the rollers 24, 26 float to the left (in the view of 
FIG. 7) and are urged against the log 200' by the spring 90. FIG. 8 shows 
a similarly misaligned small diameter log 202' with the rollers 24, 26 
urged against the log 202' by the spring 90. 
From the foregoing detailed description of the preferred embodiment, it has 
been shown how the present invention has been attained. Modifications and 
equivalents of the disclosed concepts are intended to be included within 
the scope of the claims which are impended hereto.