AU2013266993A1 - Garden refuse shredding apparatus - Google Patents

Abstract

Apparatus for shredding garden refuse is disclosed. The apparatus comprises a housing defining a chamber comprising first and second housing parts which are closed in operation but which may be opened up to provide access to the chamber for servicing. The apparatus also includes a drive shaft rotatably mounted on the housing and a rotor mounted on the shaft and positioned within the chamber. There are also means, eg in the form of an electric motor, for driving the rotor. The apparatus also includes a friction brake for engaging a brake surface associated with the shaft and rotor and biasing means in the form of a helical coil spring for biasing the friction brake into engagement with the brake surface. The brake which is on the one housing part has a brake handle and there is a latch on the other housing part for latching the brake handle in the disengaged position. The latch is disengaged when the housing pars are opened up causing the brake to slow the shaft and rotor to a stop within a few seconds. cBAR10171filed3December2013

Description

GARDEN REFUSE SHREDDING APPARATUS TECHNICAL FIELD This invention relates to garden refuse shredding apparatus that is suitable for shredding plant matter including leaves, twigs, palm fronds and small branches. This invention relates particularly to the safety features of a garden shredding apparatus. BACKGROUND ART Many types of garden refuse shredders are currently available and typically they include an inlet hopper which can be loaded with garden refuse for shredding as well as a small bore inlet tube for introducing small branches to be shredded. Mostly these machines utilise a flail assembly at the base of the hopper for shredding material fed through the hopper and a separate chipper assembly at the base of the small bore inlet tube for chipping small branches introduced therethrough. Disadvantages associated with these types of shredders stem from their relative complexity often making servicing, such as drive belt and blade sharpening operations, difficult and unreliable. Furthermore the flail assembly is often readily accessible from the underside of the machine making them dangerous for operation around children. In addition the flail assembly shreds green leafy material to a very fine form which may not be the most suitable for garden mulching operations Attempts have also been made to provide garden refuse shredding apparatus based on a simple shredding rotor such as is used in domestic rotary mowers. However because of the nature of materials which are fed to such apparatus such as long fibrous articles including palm fronds, long grass and tree refuse, it is common for the material to become entangled cBAR10171filed3December2013 2 about the drive shaft of the spinning rotor. This entanglement can build up to such extent that it jams the machine and prevents further operation thereof or substantially reduces the efficiency of operation thereof. In some instances such entanglement about a drive shaft can damage seals and the like which extend about that drive shaft. Any build-up of such refuse is also undesirable as it will impede the throughput of refuse and cause fouling about the drive shaft. Garden refuse shredders and other driven garden appliances are often operated by stand-alone petrol engines and electric motors fed by a power cord from the mains. Mains fed electric motors may be switched on and off remotely from the implement without knowledge of the user. This can lead to dangerous operating conditions as when operated many such electrical implements operate relatively silently. Inadvertent contact with a active parts of the implement may result with consequent injury to a user. This is particularly so in the case of garden refuse shredders where operators may wear ear muffs and where the spinning chipper rotor is a heavy object rotating at high velocity. Safety issues are a constant worry with this type of apparatus. Over the years many accidents have occurred with lawn mowers. This shredding apparatus has a similar potential for accidents to occur. There would always be a concern that a person would open the apparatus to gain access to the chamber while the blades are rotating at speed. Accidents will not occur if the power is disconnected before the apparatus is opened up to provide access to the rotor and blades. One way of helping to reduce the likelihood of accidents is to educate users by means of operating instructions and warnings on the packaging and the apparatus. cBAR10171filed3December2013 3 However, experience shows that people still open up the housing without disconnecting the mower. It is a constant challenge to innovators in this field to devise features that reduce the likelihood of this occurring. This application endeavours to at least to ameliorate this problem. SUMMARY OF THE INVENTION According to one aspect of the invention there is provided garden refuse shredding apparatus including: a housing defining a chamber comprising first and second housing parts which are closed in operation and which may be opened up to provide access to the chamber for maintenance and the like; a drive shaft rotatably mounted on the housing; a rotor mounted on the shaft and positioned within the chamber for shredding refuse; drive means for driving the drive shaft and associated rotor; and a brake means for braking the rotor when the housing parts are opened. The brake means may comprise a friction brake for engaging a brake surface associated with the rotating shaft and the rotor; a biasing means for biasing the friction brake into engagement with the brake surface; and holding means for releasably holding the brake in a disengaged position when the apparatus is in operation and the housing parts are closed. The friction brake may include a brake handle or brake lever moveable between engaged and disengaged positions corresponding to engagement and disengagement of the brake, and the holding means may include a latch for latching the handle in the disengaged position. cBAR10171filed3December2013 4 One housing part may be an upper housing part and the brake, shaft and rotor may be mounted to the upper housing part, and the other housing part may be a lower housing part positioned beneath the upper housing part. The brake may include a replaceable friction pad mounted on the upper housing part and a disc or hub mounted on the shaft for engaging the pad. The brake handle may typically and conveniently be mounted on the upper housing part, and the latch may be mounted on the lower housing part. Conveniently the latch may be formed by a locking post projecting up from the lower housing part through an aperture in the upper housing part, and the brake handle may have a complementary latching formation for engaging the latch. This may be in the form of a bracket defining an opening through which the locking post is passed. The locking post may be waisted, and the latching formation on the handle may be keyed to engage the waist, eg such that there is a locking engagement although the post can be released by deliberate movement in a particular direction. The resilient biasing means may be a helical coil spring under tension extending between the brake handle and the upper housing part. The apparatus may also include switch means for switching off power to the drive means when the housing parts are opened. This is a safety feature that stops the engine running when the housing is opened. Typically the switch means may be electrically connected to the drive means and switch off power to the drive means in response to the brake handle being moved to the engaged position. cBAR10171filed3December2013 5 In a preferred form the switch means includes a switch that is mounted on the first housing part adjacent to the brake handle, and an element mounted on the brake handle to which the switch is responsive when the brake handle moves to the engaged or disengaged position. Typically the switch and co-acting or cooperating element closes an electrical circuit when the brake handle is in the disengaged position allowing electrical power to go to the drive means and opening the circuit and shutting off power when the brake handle is in the engaged position. The apparatus may further include fastening means for releasably fastening the housing parts to each other in the closed position. In a preferred form the housing parts are pivotally attached to each other on one side of the housing and releasably attached to each other on an opposed side of the housing, and the releasable attachment is effected by wing nuts or other nuts. Wing nuts can be manually undone and therefore preferred. The apparatus may further include a flag proximate to the locking post that is moveable between an access position where it permits the brake handle to be engaged with the locking post, and a blocking position in which it interferes with and resists engagement of the brake handle with the locking post. This provides another safety feature in addition to the latch. The flag may be positioned in the access position when the two housing parts are properly closed and positioned in the blocking position when the two housing parts are not properly closed. The apparatus may include a biasing means for biasing the flag to the blocking position where it interferes with the brake handle. The flag is moved relative to the upper part by the proper closing of the housing parts to the access position cBAR10171filed3December2013 6 where it permits the brake handle to be latched. In a preferred form the flag moves substantially vertically between a lower position in which it is in the blocking position and an upper position in which it is in the access position, and a leading edge of the flag is tapered or configured such that a part thereof projects outwardly proud of the remainder of the edge to block the brake handle in the lower position but said part is upwardly clear of the brake handle in the upper position to permit access. With the foregoing in view, this invention in another aspect resides broadly in garden refuse shredding apparatus including: a chamber having a refuse inlet and an outlet for shredded material; fan means for creating an outflow of air from said outlet; a shredding rotor supported for rotation in the chamber; at least one elongate chipper blade fixed for rotation with the rotor and extending inward from adjacent the outer periphery of the rotor; a respective aperture through the rotor in front of the or each chipper blade through which material shredded by the chipper blade may pass; a feed hopper for directing refuse through the refuse inlet into the chamber in the path of the chipper blade or blades, and drive means for rotating the rotor. Suitably the fan means are supported on the rotor and induce an air flow through the feed hopper so as to assist in induction of material introduced to the feed hopper into the housing and each elongate chipper blade extends inward from adjacent the outer periphery of the rotor substantially to or eBAR10171filed3December2O13 7 beyond the half radius position of the rotor. Alternatively an air flow may be induced by an exhaust fan associated with the outlet from the chamber and air may be introduced either through the hopper or elsewhere. The induction may be such as to cause the feed of refuse from a storage into the chamber or the feed hopper may feed gravitionally into the chamber and the air flow may be used to assist induction of the refuse into the chamber. The shredder may include a pipe inlet through which branches and the like are fed to the shredding rotor which is suitably in the form of a heavy rotor having one or more relatively long chipper blades mounted thereon adjacent a complementary aperture through the rotor. The or each chipper blade suitably has an outer portion which passes across the pipe inlet and the outer portion of the inlet, while the inner portion of the chipper blades pass only across the inner portion of the inlet. For example the inlet is suitable part-circular and extends across about between one-half and three-quarter of the rotors radial extent, while the pipe inlet extends across one-third of the rotor's radial extent. In one desired form which utilises gravity feed of refuse to the chamber, the feed hopper extends upwardly from an upper end wall of a chamber in which a shredding rotor is supported for rotation about an upstanding axis and fan blades are mounted on the shredding rotor at the side thereof remote from the feed hopper, the fan blades forming the fan means. The shredding rotor may be supported for rotation about a horizontal axis or an inclined axis. It is preferred that the shredding rotor be mounted for direct drive from the output shaft of the drive motor which may be an electric motor or an internal combustion engine. In the case of an internal cBAR10171filed3December2Ol3 8 combustion engine it is preferred that the shredding rotor be fixed to a hub which rotates with the output shaft of the motor. Suitably the hub extends about the output shaft and is supported by a bearing mounted to an end wall of the chamber. The chipper rotor and bearing may be supported on the lower end wall and be connected to the motor such as by a splined or dog connection. Suitably however both the motor and the bearing for the hub are mounted to the upper end wall of the chamber containing the shredding rotor. Preferably the bearing is of the type which isolates end and radial loads applied by the shredding rotor from the engine. In this manner the outer end of the output shaft is supported by the hub bearing against loads imposed by the rotor. Preferably the hub bearing is a self-aligning bearing of the type which may be locked to the hub, such as a self aligning cam-lock sealed ball bearing, which is locked to the hub after adjusting end play of the engine shaft so as to reduce end loads being transferred to the crankshaft of the engine. For this purpose it is preferred that the engine is supported on a bracket above the hub bearing in such manner that access may be gained to the hub bearing for locking purposes after securing of the rotor to the output shaft. This arrangement provided a very simple and cost effective means of achieving reliable operation with direct drive from an internal combustion engine. It is desirable that the shredding rotor be provided with means to prevent stringy material from becoming entangled about the hub of the rotor. In one form this includes the provision of macerator blocks or blades mounted on the end wall of the rotor housing. cBAR10171filed3December2013 9 In a particular embodiment of the invention the shredding rotor is enclosed for rotation within a two part housing and is supported for rotation from a nominally horizontal upper end wall of an upper housing portion which also carries the motor and the hopper and which is hinged to a lower housing portion from which the upper housing portion may be pivoted to an open position to expose the shredding rotor. In this form the lower housing part is suitably supported on skids or wheels. This configuration of the rotor housing also constitutes another aspect of this invention and may be utilised to advantage without being limited to utilising the particular shredding apparatus described above. Similarly the configuration of the motor and rotor mounting utilising a separate bearing to isolate the rotor loads from the direct mounted motor shaft constitutes a further aspect of this invention and may be utilised to advantage without being limited to utilising the particular shredding apparatus or housing described above. It is also preferred that in this form the upper housing parts be provided with suspension means for suspending a catcher across an outlet aperture in a side wall of the housing. Suitably the catcher is mounted remote from the hinging mechanism and preferably the outlet constitutes the end of a volute shaped housing which provides an expanding path to the outlet. It is also preferred in such arrangement that an induced air draught by utilised to assist in feed through the feed hopper and discharge of shredded material through the outlet. In a further aspect this invention resides broadly in a rotary processor such as garden refuse shredder having a driven shaft driving a shredder mounted within a housing, an cBARI1Ol7lfited3December2O13 10 inlet to the housing for refuse to be shredded and an outlet from the housing for discharging shredded refuse, wherein: impeller means are associated with the shredder for inducing an inflow to the housing through the inlet and an outflow from the housing through the outlet. Suitably the housing provides an expanding travel path for material entering through the inlet and passing to the outlet and more suitably this travel path is in the form of a volute or the like. The drive shaft may be driven by an electric motor or by an internal combustion engine, in which case it is preferred that the shredder be mounted on the output shaft but supported by bearing means independent of the internal combustion engine. The drive shaft may be a horizontal shaft or a substantially vertical shaft. The shredder is suitably a relatively heavy disc supporting chipper blades thereon and having apertures therethrough in front of the blades and through which shredded refuse may pass to be discharged. In an electrically driven form of this invention in which the shredding rotor is supported on the output shaft of an electric motor, the shredding rotor suitably includes a friction brake biased to an engaged attitude so as to cause the shredding rotor to slow quickly to a stopped position once electrical power to the driving motor has ceased and a manual on/off control associated with an onboard electrical switch which controls the supply of electricity to the motor such that when the control is moved to the on position for supplying electricity to the motor the brake is maintained in a disengaged position and when the control is moved to the off position the brake is freed for stopping the shredding rotor. Suitably the brake is a single shoe brake carried on a lever for movement to and from its engaged attitude and co operable with a switch in its disengaged position to supply eBAR10171filed3December2013 11 electricity to the motor. The brake is suitably arranged as a leading shoe brake such that the effort to operate the brake effectively is reduced. The shredding rotor may also be supported within a shredder housing which is opened to provide service access to the shredding rotor and suitably a latching arrangement is provided for holding the brake lever or other manual on/off control when in the on position in a blocking position blocking the opening of the shredder housing. The shredding rotor may be supported in a volute shaped housing and be provided with wind vanes for creating an air flow therethrough from the refuse inlet to the outlet from the shredder housing. A barrier wall may be provided about the output shaft of the motor as a guard against elongate fibrous articles becoming entwined about the shaft. Cutters mounted on the rotor of the shredding rotor and arranged to pass across fixed anvils may be provided to disrupt fibrous articles that pass toward the output shaft also with a view to preventing elongate fibrous articles becoming entwined about the shaft and in a further aspect of this invention the cutters are suitably in the form of hardened plates extending upwardly through slots through the rotor to pass close to the fixed anvils. Each plate may be welded to a mounting flange which is bolted to the underside of the rotor and preferably with bolts which trail the plate. BRIEF DESCRIPTION OF DRAWINGS In order that this invention may be more readily understood and put into cBAR10171filed3December2013 12 practical effect, reference will now be made to the accompanying drawings which illustrate a typical embodiment of the invention and wherein: Fig 1 is a side view of the shredding apparatus fitted with a catcher; Fig 2 is corresponding view but shown without a catcher; Fig 3 illustrates the shredding apparatus disposed in a servicing mode; Fig 4 is a part-sectional view of the rotor and its mounting; Fig 5 is a cutaway plan view of the rotor assembly, and Figs 6 and 7 illustrates in plan and side sectional views a further embodiment of the rotor assembly. Figs 8 and 9 illustrate in plan and side sectional views a further embodiment of the rotor assembly and its mounting details; Fig 10 is a cross-sectional view of the rotor and shaft and associated mounting on the upper housing part; Fig 11 is an exploded three dimensional view of the rotor and associated blades; Fig 12 is a three dimensional view of an apparatus in accordance with a second embodiment of the invention; Fig 13 is a three dimensional view of the apparatus of Fig 12 with the housing parts in the open position; Fig 14 is a bottom plan view of the apparatus of Fig 12; Fig 15 is a schematic three dimensional view of a brake for braking the shaft and an associated switch for shutting off power to the motor, for the apparatus of Fig 14; Fig 16 is a three dimensional view of the brake handle of Fig 15 in an on position; Fig 17 is a three dimensional view of the brake handle of Fig 15 in an off position; eBAR0171filed3December2013 13 Fig 18 is a schematic three dimensional view of a 'brake assembly which is a variation on that of Fig 15 in an on position; Fig 19 is a schematic three dimensional view of the brake assembly of Fig 18 in the off position. MODES FOR CARRYING OUT THE INVENTION The garden refuse shredding apparatus 10 illustrated in the drawings has a two-part housing 11 supported on rear wheels 12 and a front stand 13, a feed hopper assembly 14 and a small bore inlet tube 15 extending upwardly from the upper housing part 16 and a catcher 17 suspended from the front of the housing 11. The housing 11 contains a shredding rotor assembly 20, illustrated in Fig. 4, and supports a small petrol motor 21 thereabove for driving the shredding rotor assembly 20. Opposed pin hinges 22 attach the upper housing part 16 to the lower housing part 19 at the rear thereof which enable the upper housing part 16 and the components mounted thereon to fold to an open position, as illustrated in Fig. 3, at which the handle 24 rests on the ground and clear access is provided to the shredding rotor assembly 20 through the open underside of the top housing part 16. The front of the top housing part 16 is retained on the lower housing part 19, in use, by bolts 25. As illustrated in Figs. 4 and 5, the shredding rotor assembly 20 has a disc-like rotor 28 formed with opposed radially extending slots 27 at diametrically opposite positions and a chipper blade 30 bolted to the rotor 28 ) adjacent the trailing side of each slot 27. Macerator blocks 29 are interposed between the blades 30 and are fixed to the rotor 28 with inner ends spaced from the eBAR10171filed3December2013 14 hub 31 to which the rotor 28 is bolted. Pins 32 extends down from the end wall 33 of the upper housing part 16 toward the rotor 28. The pins are positioned between the hub 31 and the macerator blocks 29. The hub 31 is formed at the lower end of a thick-walled sleeve 35 which is bored to accept the output shaft 36 of the motor 21 which is keyed thereto by a key in conventional manner. The lower end of the motor shaft 36 is threaded to receive a retaining bolt 37 which pulls the rotor 28 against the end of the shaft 36. The rotor is also bolted to the hub 31 by bolts 38. The sleeve 35 is supported by a large capacity self aligning cam-lock bearing 40 which is secured to the end wall 33 through a stiffening boss 41. This bearing is locked to the motor shaft 36 so as to support the weight of and end thrust placed upon the rotor 28. The bearing 40 also accommodates the side and impact loads imparted by the operation of the chipper blades 30. This isolates undesirable loads being applied to the crankshaft of the directly mounted motor 21 which is supported on a channel shaped mounting 23 fixed to the end wall 33. The rotor 28 is relatively heavy and acts as a flywheel and in a typical embodiment is formed from 5mm thick steel plate. The underside of the rotor 28 has impeller blades 44 bolted thereto so as to create an air flow through the open front 45.of the housing 11. This induces a downdraught through the feed hopper assembly 14 and the small bore inlet tube 15 which assists in feeding material to be mulched therethrough toward the rotor 28. A closure cap may be provided for the tube 15 to increase the draught through the hopper assembly 14. The induced draught also carries shredded material cBAR10171filed3December2013 15 through the outlet which is normally closed by a flap 47 hinged along its upper edge and pivotable upwardly to permit a conventional grass catcher 50 to be removably clipped to the housing 11 to receive the shredded material It will be seen that the feed hopper assembly 14 has a forwardly convergent transition piece 51 extending from its underside to the inlet aperture 52 formed in the top wall 33, while the inlet tube 15 is angled back to assist feeding of the material introduced therethrough. In use when the rotor 28 is rotated at high speed, air is induced to flow through the feed hopper assembly 14 and inlet tube 15, which may be capped if desired. This air flow assists in the feeding of material to be shredded to the rotor 28. Most of this matter will be shredded by the chipper blades 30 and pass through the apertures 27 for discharge to the catcher. Should refuse move across the top of the rotor 28 toward the hub 31 it will be contacted by the macerator blocks 29 and be pulverised. The air draft induced by the fan blades 44 will assist in discharging the pulverised material. In the event that the chipper blades need servicing, they can be accessed easily be releasing the bolts 25 and pivoting the top housing part to its open position as illustrated in Fig. 3. In this position the rotor 28 is stably supported for safe working conditions. An inlet safety flap 48 is pivotally attached to the upper end of the hopper to close the hopper after the addition of material to be shredded. The flap 48 does not extend fully to the front wall 53 of the hopper 14 so as to provide an ) opening or air flow gap for maintenance of a desirable air flow through the feed hopper 14 to assist with the feeding and/or discharge process. eBAR10171filed3December2013 16 An alternate rotor 58 illustrated in Figs. 6 and 7 carries opposed blades 56 formed with upturned inner ends 57 to provide cutters which co-act with complementary arcuate blade 59 centred on the rotor axis and fixed to the end wall 55 of the upper housing part. The cutters 57 pass close to the blades 59 and cut up long strands of matter which may be fed toward the boss 54. However the rotor arrangements of Figs. 4 to 7 are not particularly suited to coping with various types of refuse such as palm frons for example. These are more efficiently coped with by the shredding rotor assembly illustrated in Figs. 8 to 13 and described below. The preferred form of shredding rotor assembly 60 has opposed blades 61 bolted to the rotor 69 and formed with upturned cutting or disrupting ends 62 which are L-shaped to pass closely about the end face 63 and side face 64 of circular anvils 65 which in this embodiment are constituted by Allen head bolts which bolt the end wall 66 to the robust housing of the cam-lock nearing 67. The bolts 65 are high tensile bolts which have relatively deep serrated cylindrical heads. With this arrangement the close spacing between the L shaped ends 62 with the side and end faces of the bolts 65 will not vary with rotation of the bolts 65. An annular barrier wall 70 extends down from the end wall 66 to terminate closely adjacent the rotor 69. The barrier wall 70 closely accommodates the lower mounting flange 72 of the hub assembly 71 which is carried by the cam-lock bearing 67. This hub is keyed to the driveshaft 73 of the motor 74 and a central retaining bolt extends through the rotor 69 into the driveshaft 73. As can be clearly seen in Fig. 10, when the blades 61 are in line with one of the bolts 65 the only path thereacross to the hub assembly 71 is a circuitous or labyrinth path as cBAR10171filed3December2013 17 indicated by the arrow 75, and being first about the side and end fact of the bolts 65 and then past the barrier wall 70. This will provide an effective barrier against elongate fibrous articles entwining about the shaft. Material which travels inward beyond the chipper blades 76 will be resisted by the barrier wall 70 where it will be cut up or disrupted and then forced outwardly either by the motion of the rotor or the air flow across the rotor 69. The through bolts for the chipper blades 76 also secure the impeller blades 77 to the rotor 69. These figures illustrate the simple and easy to manufacture nature of the shredding apparatus, being formed mostly of folded sheet metal bolted together and punched for bolt on mounting of the components such as the motor and bearing assembly. This arrangement provides a shredder of very simple form which has the bulk of its weight centralised between the wheels 12 and the stand 13 for stable operation. The weight of the hopper is offset by the catcher and the handle 24 provides for simple balanced wheeling of the shredder 10 from location to location and support for the opened housing. The garden refuse shredder assembly 110 illustrated in Figs 12 to 14 of the drawings has a shredding rotor assembly 111, as illustrated in Fig. 20 supported in a housing 112 and driven by an electric motor 113. An inlet chute 114 is provided at the rear of the housing for entry of garden refuse and an outlet chute 115 is provided at the front of the housing through which shredded material is discharged. In this embodiment, the housing 112 is a two part housing having an upper part 120 pivotally connected by pivots 121 to a base part 122 such that the upper part 120 may be opened ah shown in Fig 13 to provide access to the shredding rotor eBAR10171filed3December2013 18 assembly 111. Normally the housing parts are retained in their closed attitude by a pair of wing nuts which bolt the upper part 120 to the base part 122. As shown in Fig 12 the base part 122 is provided with an upstanding pin 130 which passes through a complementary aperture 133 in the upper housing portion 120 when the housing is closed. The upper end 131 of the pin 130 is then exposed above the upper housing 120 as illustrated in Figs 12. The shredding rotor assembly 111 is provided with a mounting hub 135 which received the keyed output shaft of the electric motor 113. The upper portion of the hub 135 extends upwardly above the housing 120 into a cavity formed by an inverted channel shaped motor mounting bracket 136. The motor mounting bracket supports a brake lever 137 which carried a brake pad 138 and tension spring 139 which biases the brake pad 138 into engagement with the upper portion of the hub 135. The brake lever 137 extends forwardly through the front flange 140 of the motor bracket 136 and beyond the exposed upper end 131 of the pin 130 which projects through the housing 120. An on/off switch 141 is also carried on the motor mounting bracket so as to co-operate with the brake lever such that when the brake lever is disengaged from the hub 135 and held in the "ON" position, it will actuate the switch 141 to an on position such that external electrical power supplied to the shredder will be switched to the motor 113. When the lever 137 returns to the engaged position, it releases from the switch 141 which becomes open circuit so as to prevent supply of electricity to the motor 113. This will stop the application of drive to the rotor. Once disengaged from an "ON" position, the biasing of the lever 137 will urge the brake pad 138 into braking contact cBAR10171filed3December2013 19 with the hub 135 to brake the rotor assembly 11 to a standstill in a relatively short space of time, such as a matter of seconds. The end 145 of the lever 137 which is exposed above the housing part 120 forms an on/off control switch for the shredder and it is adapted to be retained in the "ON" position by engaging it with the exposed upper end 131 of the pin 130. For this purpose, the upper end 131 of the pin 130 is waisted at 150 and the end 145 of the lever is provided with a keyhole slot 151 whereby the end portion 145 may be captively engaged with the upper end 131 of the pin 130 and held therein by its spring bias.When so engaged, the switch 141 is maintained closed and power is supplied to the motor 130. Should an operator want to gain access to the rotor assembly 111, the operator may undo the wing nuts 142 with a view to pivoting the upper part 120 of the housing 112 to the open position. This may be achieved provided the on/off lever 137 is not engaged about the upper end of the pin 130. If it is so engaged and the electric motor is powered, then captive engagement of the lever end 145 with the pin end 131 will prevent the upper housing part 120 being pivoted to its open position. thus the housing cannot be opened to gain access to the rotor assembly 11 unless the lever 125 is in the off position. When the lever end 145 is released from the pin end 131, the spring 139 will pull the lever 137 to the braking position stopping power supply to the motor and at the same time braking the rotor to a standstill. The following description will focus on the brake and associated components shown in Figs 15 to 19. It may to some extent repeat the discussion immediately above with respect to Figs 12 to 14 and is to be read bearing this fact in mind. cBAR10171filed3December2013 20 Figures 15 to 19 illustrate the apparatus in the form of a friction brake for braking the rotor and slowing it down to a complete halt within a short space of time. Broadly the brake means comprises a friction brake with a pad 138 for engaging a brake surface in the form of a disc or brake boss 135 associated with the rotating shaft and rotor. A biasing means in the forms of a helical coil spring 139 biases the friction brake into engagement with the disc or boss. A brake handle extends away from the brake pad 138 and is moveable between engaged and disengaged positions corresponding to engagement and disengagement of the brake. The brake handle is pivotally mounted to the upper housing part 122 by means of a pivot arm. These components, and particularly the friction pad 138 and the brake handle 137 are mounted on the upper housing part 120. The apparatus also includes holding means in the form of a latch for latching the handle 137 in the disengaged position notwithstanding the biasing force of the helical spring 139. In the illustrated embodiment the latch is in the form of a locking post 130 extending up from the lower housing part 122 through an opening with some spacing in the upper housing part 120. The brake handle 137 has a bracket towards the end thereof defining a key opening which is passed over the locking post 130. The post 130 may have a waisted portion 150 and the bracket may be keyed so as to received the waisted portion in a releasable locking engagement. A micro switch assembly is also mounted in proximate relation to the brake and brake handle. A micro switch assembly comprises a bracket with a micro switch mounted thereon. The micro switch is positioned to contact a sensor on the brake handle when the brake is in the disengaged position. cBAR10171filed3December2013 21 The assembly also includes a cable for effecting electrical connection to the electric motor. When the switch separates from the sensor the micro switch assembly cuts off power to the electric motor and thus it cannot run. The brake handle 137 may have a knob or control formation 145 towards the free end thereof for use by a user in moving the handle between the engaged and disengaged position. This in effect provides a manual control for the brake. In use the electric motor 113 is used to drive the rotor 111 at high speed in the chamber. This facilitates the shredding and braking up of plant matter such as leaves, branches and palm fronds. The motor 113 is able to drive the rotor 111 because the micro switch 141 is in contact with the sensor on the brake handle and the brake handle 137 is in the disengaged position. If however the brake handle 137 is lifted off the locking post 130, the spring will urge and displace the handle 137 and brake pad 138 into engagement with the brake boss 135. To open the housing up it is necessary to detach the handle 137 from the post 130 and allow the brake handle to the off position. This will therefore have the effect of applying the brake and stopping the rotor 111 as well as shutting off electrical power to the electric motor. The contact of the friction brake 138 with the boss 135 rapidly slows down the drive shaft and rotor bringing it to a complete stop within ten to twenty seconds. In addition the movement of the brake handle 137 when it is disengaged from the post will also detach the micro switch sensor on the brake handle from the micro switch cutting off the power to the electric motor immediately. The motor can only be restarted when the brake handle 137 is manually moved back into the engaged position in which it cBAR10171filed3December2013 22 is in latching engagement with the locking post 130. This requires a quite deliberate action on the part of a user. The housing parts 120, 122 need to be substantially closed before the handle 137 can be engaged with the locking post 130. This to some extent at least confers some safety protection. Figs 18 and 19 illustrate a variation on this embodiment. Unless otherwise indicated the same reference numerals will be used to refer to the same components. The following description will focus on the difference between this embodiment the previous embodiment. This embodiment has a flag 180 with a leading edge 181 of varying profile that engages the brake handle 137. The flag 180 moves vertically between a relatively lower blocking position in which it block the handle 137 from engaging the locking post 130 and a relatively upper access position where it permits the handle 137 to get access to and be mounted over the locking post 130. The flag 180 is biased by means of a spring 184 to the locking position. The flag 180 is only moved to the access position when the housing parts 120, 122 are properly closed. This moves the flag 180 upwardly such that the locking edge 181 is out of alignment with the brake handle 137 permitting it to be mounted over the locking post. In one form the spring 184 may be loaded under compression and acting between the lower housing 122 and the upper housing 120. This feature is useful to further enhance the safety of this apparatus. In the description and also elsewhere in the specification the term brake handle is used interchangeably with the term brake lever used elsewhere in the specification. cBAR10171filed3December2013 23 A brake handle and brake lever are to be construed as one and the same thing. Referring to Fig 14 it will be seen that the brake lever 137 is arranged with the pivot mounting at a leading position relative to the rotation of the hub 135 such that the brake assembly is a leading show brake assembly which provides a self servo effect to assist actuation by the tension spring 139. It will also be seen from the drawings that the rotor assembly 111 operates in the volute shaped housing and is provided with fan blades 161 adjacent the apertures 162 in front of the chipper blades 128. The fan blades induce a draft through the feed chute 114 and through the outlet 115 to assist in through flow and discharge of shredded material. It will be further seen that an annular barrier wall 163 is formed around the output shaft 163 of the motor 113 so as to shroud the hub 135. Fixed circular anvils which are preferably serrated and constituted by the heads of Allen head bolts 165 are mounted adjacent the barrier wall 163 and complementary L-shaped cutting blades 166 extend through slots 167 in the rotor 11. The blades 166 are welded to mounting plates which are bolted to the rotor 11 by trailing bolts 169. The L-shaped cutters 166 pass closely over the outside and lower end of the circular anvils 165 so as to cut up any fibrous material which may pass through the inlet 126 and move inwards above the rotor 11. In the illustrated embodiment the outlet 115 is provided with a deflector 170 which deflects discharged material towards the ground. The deflector however may be pivoted to an inoperative position so as to permit a catcher to be engaged with the outlet to receive shredded material. In operation the upper end of the inlet chute 114 is eBAR10171filed3December2013 24 normally covered by a safety flap which does not prevent flow of air induced by the low pressure created by the fan blade 161. Thus once operating, there is a significant air flow induced in the inlet chute to assist feed of material to the cutter assembly and from the outlet to assist in discharge of shredded material. As the material is fed through the inlet, it is engaged between the anvil 127 and a chipper blades 128 and chipped. It is then flung outwardly and discharged with the aid of the induced draft. This operation can only occur when the lever 145 is engaged about the pin 130 as illustrated in Fig 16. If the operator desires to service the rotor 11, the upper part of the housing 120 cannot be opened until the lever 145 has been freed from the pin 130 for movement to the braking position. Thereafter the wing nuts 142 can be released to enable the housing parts to be opened. A further accessible master switch may be provided is desired to provide an operator with a direct means of switching the power supplied to the shredder assembly 110 or placed elsewhere as desired. It will of course be realised that the above has been given by way of illustrative embodiment of the invention, all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is defined in the appended claims. cBAR10171 filed3December2013

Claims (19)

1. A garden refuse shredding apparatus including: a housing defining a chamber comprising first and second housing parts which are closed in operation and which may be opened up to provide access to the chamber for maintenance and the like. a drive shaft rotatably mounted on the housing; a rotor mounted on the shaft and positioned within the chamber for shredding refuse; drive means for driving the drive shaft and associated rotor; and a brake means for braking the rotor when the housing parts are opened.

2. A garden refuse shredding apparatus according to claim 1, wherein the brake means comprises a friction brake for engaging a brake surface associated with the rotating shaft and the rotor; a biasing means for biasing the friction brake into engagement with the brake surface; and holding means for releasably holding the brake in a disengaged position when the apparatus is in operation and the housing parts are closed.

3. A garden refuse shredding apparatus according to claim 2, wherein the friction brake includes a brake handle moveable between engaged and disengaged positions corresponding to engagement and disengagement of the brake, and the holding means includes a latch for latching the handle in the disengaged position. cBAR10171filed3December2013 26

4. A garden refuse shredding apparatus according to claim 3, wherein one housing part is an upper housing part and the brake, shaft and rotor are mounted to the upper housing part, and the other housing part is a lower housing part positioned beneath the upper housing part.

5. A garden refuse shredding apparatus according to claim 4, wherein the brake handle is mounted on the upper housing part, and the latch is mounted on the lower housing part.

6. A garden refuse shredding apparatus according to claim 5, wherein the brake includes a replaceable friction pad mounted on the upper housing part and a disc or hub mounted on the shaft for engaging the pad.

7. A garden refuse shredding apparatus according to claim 6, wherein the latch comprises a locking post projecting up from the lower housing part through an aperture in the upper housing part, and the brake handle has a complementary latching formation for engaging the latch.

8. A garden refuse shredding apparatus according to claim 7, wherein the locking post is wasted, and the latching formation on the handle is keyed to engage the waist.

9. A garden refuse shredding apparatus according to any one of claims 2 to 8, wherein the resilient biasing means is a helical coil spring under tension extending between the brake handle and the upper housing part. eBAR10171filed3December2013 27

10. A garden refuse shredding apparatus according to claim 3, further including switch means for switching off power to the drive means when the housing parts are opened.

11. A garden refuse shredding apparatus according to claim 10, wherein the switch means is electrically connected to the drive means and switches off power to the drive means in response to the brake handle being moved to the engaged position.

12. A garden refuse shredding apparatus according to claim 11, wherein the switch means includes a switch that is mounted on the first housing part adjacent to the brake handle, and an element mounted on the brake handle to which the switch is responsive when the brake handle moves to the engaged or disengaged position.

13. A garden refuse shredding apparatus according to any of claims 1 to 12, further including fastening means for releasably fastening the housing parts to each other in the closed position.

14. A garden refuse shredding apparatus according to claim 13, wherein the housing parts are pivotally attached to each other on one side of the housing and releasably attached to each other on an opposed side of the housing, the releasable attachment being effected by wing nuts or other nuts. cBAR10171filed3December2O13 28

15. A garden refuse shredding apparatus according to claim 7, further including a flag proximate to the locking post that is moveable between an access position where it permits the brake handle to be engaged with the locking post, and a blocking position in which it interferes with and resists engagement of the brake handle with the locking post.

16. A garden refuse shredding apparatus according to claim 15, wherein the flag is positioned in the access position when the two housing parts are properly closed and is positioned in the blocking position when the two housing parts are not properly closed.

17. A garden refuse shredding apparatus according to claim 16, including a biasing means for biasing the flag to the blocking position where it interferes with the brake handle, but wherein the flag is moved relative to at least one of the housing parts against the bias by the proper closing of the housing parts to the access position where it permits the brake handle to be latched.

18. A garden refuse shredding apparatus according to claim 17, wherein the flag movessubstantially vertically between a lower position in which it is in the blocking position and an upper position in which it is in the access position, and a leading edge of the flag is tapered or configured such that a part thereof projects outwardly proud of the remainder of the edge to block the brake handle in the lower position but said part is upwardly clear of the brake handle in the upper position to permit access. cBAR10171filed3December2O13 29

19. A garden refuse shredding apparatus substantially as herein described in the detailed description of the preferred embodiments with particular reference to the embodiments illustrated in Figures 15 to 19. cBAR10171fled3December2l13