Patent Application
20230211354
The present invention relates to a wood chipper. More particularly, the present invention relates to a wood chipper with an adjustable feed hopper.
Wood chippers are well known as an apparatus used to process fallen or cut branches and/or similar debris or refuse (vegetative debris), turning this into chips and/or mulch. A typical wood chipper is made up of three main parts: a hopper, a chipper unit, and discharge chute. Debris such as branches, etc is manually loaded into the hopper, which in use is set upright at an angle. The debris feeds through the hopper under gravity, into the chipper unit. A typical chipper unit has a set of blades that rotate in a plane at an angle to the feed direction of the wood, so that as the wood/debris enters the chipper unit the blades chop small pieces off the branch or other item as they rotate and the branch is fed into the blades, so that over a short period of time it is cut into small fragments - that is, chipped. Most chipper units have a rotary blade unit, where the blades are connected to or form part of a blade carrier in the form of a bladed disc or short cylinder. The blade carrier rotates so that the blades connect with the wood at an angle as this is fed into the wood chipper.
The chipped wood fragments pass through the chipper unit and out of the wood chipper via the discharge chute.
Typically, the hopper is aligned upright, at an angle between fully horizontal and fully vertical. Branches and debris placed in the hopper will therefore slide down inside the hopper (gravity feed), and enter the chipper at the bottom of the hopper, at an angle to the blades.
For harder woods, it is preferred to use a chipper with the hopper aligned more upright, or closer to vertical. Hardwood or dry wood often requires a pushing force to be exerted to push the wood into the blades of the cutting block of the chipper. The steeper angle helps to ensure that the wood is ‘self-feeding’ under gravity, and that no or minimal extra force is required form an operator. This steeper angle also means that contact between e.g. a branch and the blades is closer to a right angle (that is, at the point of contact in a chipper having rotating blades, the blades will be travelling near-horizontally at the top part of their route of travel. With the hopper aligned closer to vertical, the wood/blade contact therefore occurs at an angle closer to perpendicular). This arrangement also means that the wood ‘drops’ faster through the hopper, and enters the chipper unit at a faster speed than it would for a shallower hopper angle. A faster feed, and/or an angle closer to perpendicular, is more advantageous when chipping harder woods.
For softer woods it is preferred to use a chipper with the hopper aligned at a shallower angle/less upright/further away from vertical. Soft wood is easier to cut (chip), and therefore it is less crucial to have the blades and wood meet at an angle closer to a right-angle, and at speed. Also, the chips from softer wood can accumulate very rapidly within the chipper unit and cause clogging and potentially stoppages. For operations where softer woods are being chipped, the hopper is normally aligned at an angle further away from vertical (less upright), so that the wood does not feed under gravity as fast, leading to less volume passing into the chipper over any given or set time period.
US5,293,917 describes and shows a disc chipper and feeding method, where the method for feeding long pieces of wood into a disc chipper against a disc equipped with blades is carried out in such a way that the piece of wood encounters the bladed disc at a sharp input angle. The sharp input angle is achieved by combining the sharp inclination of the feeder chute with a sharp level slanting angle. This specification discusses issues and advantages with feeding wood into a chipper at different angles.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is an object of the present invention to provide a wood chipper which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.
The term “comprising” as used in this specification and indicative independent claims means “consisting at least in part of”. When interpreting each statement in this specification and indicative independent claims that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner.
As used herein the term “and/or” means “and” or “or”, or both.
As used herein “(s)” following a noun means the plural and/or singular forms of the noun.
Accordingly, in a first aspect the present invention may broadly be said to consist in a wood chipper, comprising: a hopper, having an inlet end and an outlet end, the hopper configured to receive vegetative debris via the inlet end; a chipper unit having an outer casing and an inlet passing therethrough, the inlet connected to the hopper outlet end to in use receive the vegetative debris within the casing, the chipper unit further comprising a cutting means located within the casing and configured to chip vegetative debris within the chipper unit; the hopper and outer casing configured so that the hopper and outer casing can be moved between a position where the hopper is substantially vertical and a position where the hopper is substantially horizontal.
In an embodiment, the chipper further comprises a discharge chute connected to the chipper unit and configured to receive the chipped vegetative debris and pass this out of the chipper as a stream at a point remote from the chipper unit.
In an embodiment, the chipper further comprises a motor, the motor having an output shaft connected to and driving the cutting means, the hopper and outer casing moving between the position where the hopper is substantially vertical and the position where the hopper is substantially horizontal by rotating around the axis of rotation of the motor output shaft.
In an embodiment, the chipper further comprises a fixed plate connected to the motor and a back plate connected to the chipper unit, the plates adjacent to one another, the back plate in use rotating relative to the fixed plate, apertures formed through the plates and co-incident with each other at the substantially vertical and substantially horizontal positions.
In an embodiment, the apertures comprise three position holes formed through the fixed plate and at least one backplate hole, the backplate hole aligning with each of the three position holes in turn as the hopper and outer casing are rotated between positions.
In an embodiment, the apertures comprise at least one slot formed in one of the plates, co-incident with at least one aperture formed in the other of the plates along the length of the slot as the back plate rotates.
In an embodiment, the slot or slots are formed in the fixed plate.
In an embodiment, the chipper unit is configured so that the inlet is located substantially at the mid-point in use.
In an embodiment, the chipper further comprises a stand, the motor mounted on top of the stand, the hopper and outer casing mounted to the motor adjacent to the motor and adjacent to and above the stand.
In an embodiment, the stand comprises a pair of wheels at one end and a support at the opposite end form the wheels.
With respect to the above description then, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
Further aspects of the invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings which show an embodiment of the device by way of example, and in which:
Embodiments of the invention, and variations thereof, will now be described in detail with reference to the figures.
In an embodiment, the chipper 1 comprises three main parts or subsections: a hopper 2, a chipper unit 3, and discharge chute 4. These three parts are connected to one another to form a single unit, which is located on a base section 5 that comprises a pair of wheels 6 at one end and a support section 7 at the other end, allowing the chipper 1 to be transported in a similar manner to a wheelbarrow, by lifting the support section up so that it pivots around the axis of the wheels 6, and then wheeling it on the wheels. A motor 12 is mounted on the top of the base section 5 to power the chipper unit 3.
The hopper 2 is configured to receive vegetative debris, and comprises a funnel shape, rectangular in cross-section, between one and two metres long, with a wide, open mouth end large enough to allow medium-sized branches and similar debris to be easily fed into the wide end. The lower end is arranged so that branches and debris passing through the hopper 2 feed into the chipper unit 3.
The chipper unit 3 comprises an outer casing 8, and a set of rotating blades (not shown) located within and rotating within the housing 8. The casing 8 has an entry aperture 9 and an exit aperture 10. The entry aperture 9 is sized with and connected to the lower/narrower end of the hopper 2, so that branches and debris passing through the hopper 2 feed into the chipper unit 3, at a point substantially midway up the chipper drum. That is, the entry aperture is midway up the chipper drum. This is best shown in
It has been found that if wood enters towards the bottom of the drum, this can lead to the wood becoming trapped, which can slow down or even stop rotation of the drum. Having an entry aperture at a higher point helps to avoid this. The chipper of the chipper unit is driven by a motor 12, connected to the top of base section 5. The chipper unit 3, along with the hopper 2 and discharge chute 4, is located to one side of the motor 12 and off to one side of the base section 5 - that is, offset from the base section 5.
The blades or cutting block are arranged to rotate within the chipper unit so that as branches and debris feed into the chipper unit 3 via the entry aperture 9, the blades hit these at an angle to the direction of travel, chipping pieces of the branch and turning it into chips. The chips pass through and out of the chipper unit 3 via exit aperture 10, and into the discharge chute 4.
A right-angle or close to right angle contact between wood and the blades can be achieved even with the hopper chute at an angle of approximately 45 degrees. The mid-point connection between the chipper and hopper helps to ensure that even with the hopper at this angle, the cutting block will still contact wood entering the chipper at an angle closer to a right angle. This arrangement also helps with dryer woods, which can also be hard to chip. However, it also helps to ensure that the chipper will not ‘dravd the wood in too fast - the wood will be drawn in at a speed that allows the chipper to process it without becoming clogged and slowing or stopping the machine. This is best shown in
The discharge chute 4 comprises a long thin tube, rectangular in cross section and tapering slightly to its outer end, arranged at approximately a 45-degree angle between horizontal and vertical. Chips enter the discharge chute 4 at the inner end, where it is connected to the exit aperture 10 of the chipper unit 3. The chips and other debris are blown along the discharge chute to and through the outer end. A safety cap 11 is connected to the top part of the outer end of the discharge chute 4, at an angle to the axis of the discharge chute, so that as chips are blown out of the discharge chute 4 in a stream, they are directed downwards. A truck or cart or similar can be positioned under the exit aperture, so that this is filled with the chips.
The hopper 2 and chipper unit 3 are connected to the motor 12 via an angle-adjustable coupling (described in detail below) that allows the hopper 2, chipper unit 3 and discharge chute 4 to be rotated around a substantially horizontally aligned axis of rotation co-incident with the output shaft of the motor 12. That is, the hopper 2 can be rotated between a position close to vertical, and a position close to horizontal, and can be set and locked into position at the two end points (closer to horizontal at one end and closer to vertical at the other), and locked in position at at least one position in between. A combination of a chipper plate or chipper plates 15 and fixing bolts 16 form the outer part of the chipper housing 8, these connected as shown in
This range of adjustment allows a user to choose an angle that particularly suits the type of material they are disposing of. For harder woods, the hopper 2 can be rotated to a more upright/closer to vertical angle, so that the angle at which the material meets the blades is closer to a right angle, and the speed of ‘fall’ down the chute of the hopper 2 is greater. For softer woods, the hopper 2 can be rotated to a shallower angle closer to horizontal, so that the speed is less, and there is less chance of the wood clogging the chipper unit. The hopper 2 can be rotated to whichever angle is the most suitable, depending on the particular job of the moment.
If the hopper is closer to vertical, this is more suitable as well for material such as loose leaves and vegetative matter. If the exit is closer to horizontal, this will help the leaves etc to exit the hopper.
The differences in the angles are shown in
Details of the motor are shown in
Detail of a first embodiment of angle-adjustable coupling are shown in
The output shaft of the motor 12 passes outwards horizontally from the motor 12, through the two plates, 13 and 14, and towards and into the chipper unit 3. The shaft (not shown) is perpendicular to the flat faces of the two plates 13 and 14. The shaft forms an axis of rotation for the back plate 14 (and therefore the greater chipper unit 3, and the connected hopper 2 and discharge chute 4), and provides at least partial support for the chipper unit 3, the hopper 2 and the discharge chute 4, via a connection with the blades inside the chipper unit 3. Further support is provided as outlined below.
The fixed plate 13 has three position holes 15a, 15b, and 15c passing through it, spaced in an arc across the top part of the plate 13, generally following the perimeter of the plate 13. The back plate 14 has at least one hole formed through it, on its top side, the hole or holes in the back plate 14 positioned so as to be co-incident with a hole or holes 15 in the fixed plate 13 at certain points in the rotation of the back plate. That is, as the back plate 14 rotates around the axis of rotation formed by the shaft of the motor 12, the hole or holes in the back plate 14 pass across and match the holes 15. This allows a bolt or similar to be passed through two coincident holes in the plates, so as to lock the back plate 14 in position relative to the fixed plate 13.
As the hopper 2 and discharge chute 4 are rigidly connected to the chipper unit 3, they will rotate as the back plate 14 is rotated, from a position where the hopper is generally vertically aligned (as shown in
An alternative embodiment of connection/rotation mechanism between the motor and the chipper unit is shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008049.5 | May 2020 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/054494 | 5/24/2021 | WO |
