AU785231B2 - A device for cracking nuts - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE DIVISIONAL SPECIFICATION FOR A STANDARD PATENT Name of Applicant Actual Inventor Address for Service: Invention Title: Bell Cracking Pty Ltd David Jeffrey Dillon Bell CULLEN CO Patent Trade Mark Attorneys, 239 George Street Brisbane QIld 4000 Australian A Device for Cracking Nuts The following statement is a full description of this invention, including the best method of performing it, known to us: The present invention relates to a device for cracking nuts and in particular, relates to a device for cracking round hard nuts such as macadamias and hazelnuts.

The present invention will be described with particular reference to a device for cracking macadamia nuts, however it will be appreciated that the device may be used for cracking other suitable nuts and no limitation is intended thereby.

Devices for cracking nuts are known. Early types of devices included hammer members or crushing plates. A disadvantage of such types of devices was that the crushing action resulted in an unacceptable degree of damage to the kernel. This is undesirable as whole, undamaged kernels attract a premium price. Further, the nut shells were often crushed to small pieces. Removal of crushed shell particles from the kernels is difficult and added to processing costs.

There have been a number of proposals which aim to overcome these disadvantages. One device which has been widely used and has become the industry standard is known as the "Shaw type" cracker. The Shaw cracker has a rotating disc to which are mounted a number of radial cracking blades. The disc rotates about a horizontal shaft. A stationary cracking blade is mounted at an angle to the lower half of the disc so as to define a V shaped chamber. Nuts which are fed into the device are sized within the V. As the disc rotates, the nut is cracked between the rotating and stationary blades by impact and/or shearing forces rather than a crushing action.

Although the Shaw device does not crush the nuts, in practice, nuts cracked using the Shaw type device are still subject to an undesirable degree of kernel damage. Under normal operating conditions, it has been observed that less than half the nuts cracked can be recovered as whole kernels.

It is therefore an object of the present invention to provide a nut cracking device which may at least partially overcome the above disadvantages and provide the public with a useful choice.

According to a broad form of the invention, there is provided a nut cracking device, the device having at least one nut cracking unit, each unit including two opposing blade arms each blade arm having an inwardly facing cracking blade extending along an edge thereof, the blade arms being movable with respect to each other between a nut holding position in which the nut is held between the blade arms and a nut cracking position in which the blades can engage and crack the nut.

A device of the present invention can include any number of nut cracking units.

The blade arms are movable with respect to each other. The unit may include two movable blade arms or a stationary and a movable blade arm. In one embodiment, both blade arms may be mounted for rotation about a central shaft such that they move relative to each other between nut holding and nut cracking positions. Typically a nut cracking unit has a stationary blade arm and a movable blade arm. The movable arm may be mounted for reciprocal pivotal or sliding movement.

Typically, the blade arms are aligned in a substantially vertical manner such that a nut to be cracked can be dropped into the space between the two blade arms. Typically, the arms converge towards each other to define a V shaped holding chamber. In this way, the V shape can receive, hold and size nuts of different diameters when the blade arms are in the nut holding position. In the embodiment in which there is a pivotally mounted movable blade arm, it is preferred that the pivot point is at the lower end of the blade arm. Thus smaller nuts which fall towards the lower section of the V are closer to the pivot point than larger nuts which remain towards the upper section of the V. This means that as the movable blade arm pivots to the nut cracking position the smaller nuts are cracked with smaller movement and smaller speeds than the larger nuts. This should be compared to the Shaw type cracker in which the nuts experience the opposite conditions, i.e.

the smaller nuts are cracked at higher speeds and larger blade movement than the larger nuts.

A cracking blade is located along an edge of each arm. That is each arm has a leading nut holding surface but does not have a trailing surface. This is quite different to the known devices in which movable cracking blades are mounted to a disc. The disc has a leading and trailing surface to each side of a cracking blade. Whilst not wishing to be bound by theory it is believed that the trailing surface may cause a second impact on the kernel after the initial cracking of the nut. This second impact may lead to kernel damage.

In the nut cracking position, the blades can engage and crack the nut by a shearing force. After the nut is cracked, the arms return to the nut holding position to receive a further nut to be cracked Typically, nuts are fed into the unit in a singular and timed manner such that a single nut can only be introduced into the unit when the blade arms are in the nut holding position. In a preferred embodiment of the present invention, the device further includes a feeding unit. Preferably, the unit is operatively associated with a moveable blade arm such that the timing of the entry of a nut into the unit is regulated by the position of the movable blade arm.

Typically, the feeding unit includes a nut storage chamber remote from the unit and a nut transfer means for transferring a single nut to the unit. The feeding unit typically includes a base member having a nut release aperture through which a nut can pass into the cracking unit and a nut is transferred from the chamber to the release aperture. A preferred transfer means Includes a moveable base wall of the storage chamber. The base wall has a nut receiving aperture and the base wall can move between a nut collecting position in which the receiving aperture is located within the chamber and a nut releasing position in which the release and receiving apparatus are aligned.

This feeding unit may be used to feed objects other than nuts in a singular manner and need not be limited to feeding nuts to a cracking unit.

According to a further form of the invention, there is provided a dispensing unit for dispensing an object in a singular manner, the unit having a base member, a dispensing aperture in the base member through which a single object can be dispensed, an object storage chamber, remote from the aperture, the chamber having a bottom wall, an object receiving aperture located in the bottom wall, means for moving the bottom wall between an object collecting position in which the receiving aperture is located within the chamber and an object dispensing position in which the receiving and dispensing apertures are aligned such that an object can pass therethrough.

By way of example only, the present invention will now be described with reference to the following figures in which: Figure 1 is a schematic front view of a preferred device of the present invention; Figure 2 is an end view of the device of Figure 1; Figure 3 is a further view of the device of Figure 1; Figures 4, 5 and 6 are sectional views of the device of Figure 1 through A-A; Figure 7 is a sectional view of a rotary version of the device of the present invention; and Figure 8 is a perspective view of the rotary device shown in Figure 1.

Figure 1 is a schematic front view of a preferred device 11 of the present invention. The device has nut cracking unit 12 having two blade arms 14, 15. The two blade arms 14, 15 are similar in construction and each consists of a length of rectangular or angle section arm bar.

One blade arm 14 is stationary and is mounted to a main frame 13. The other blade arm 15 is moveable and is pivotably mounted at one end thereof to the frame 13 at pivot point 16. The moveable arm 15 is attached at its other end to a crank arm 17. Each arm has an inwardly facing cracking blade 18, 19 mounted along an edge thereof.

Figure 2 illustrates an end view of the device. The stationary arm 14 converges towards the movable arm 15 to define a V shaped nut holding chamber 20. The V shape allows nuts 10 of different sizes to be accommodated.

Figures 1 and 2 illustrate the blade arms 14, 15 in the nut holding position. Figure 3 illustrates the blade arms 14, 15 in the nut cracking position in which the moveable blade arm 15 has moved in an approximately horizontal direction past the stationary arm 14. Figures 4, 5 and 6 illustrate in cross section along line A-A the progressive movement of the blade arm from the nut holding position to the nut cracking position so as to crack nut The direction of movement of blade arm 15 is indicated by arrow B.

Figure 4 illustrates the arms 14, 15 in the nut holding position.

Each blade arm has a nut contacting surface 21, 22 which is approximately equal in length to half of the prescribed movement of the moveable blade arm The blades 18, 19 are attached to an end of each blade arm and face towards each other. The blades are held in place by a clamping member 29.

As the moveable blade arm 15 moves to the nut cracking position as shown in Figure 5, the respective blades 18, 19 contact nut and exert a shearing force on opposite sides of a nominal sector 23. This shearing force typically causes the nut 10 to crack across the sector to produce two shell halves and an undamaged whole kernel 9. The blade arm continues its movement until the blades have completely passed each other as shown in Figure 6. The kernel and cracked shell halves may then fall and be collected.

It can be seen that as the blades 18, 19 are at the edge of each arm, there is little change of a second impact to the kernel or nut. In this way damage to the kernel may be minimized.

The device also includes means (not illustrated) for adjusting the depth that the blade extends from the respective blade arms 14, 15. The blade depth must be sufficient to crack the nut but less than the thickness of the nut shell such that the blade does not contact and damage the kernel.

The blade depth, or cracking depth, is also adjustable along the length of the blade arm such that it can be set as a profile that changes continuously depending on nut size. For example, the depth can be adjusted such that the cracking depth at the upper section of the blades which crack larger nuts is deeper than the cracking depth at the lower sections which crack the smaller nuts. The adjustment may be made by providing a set-screw at the top and bottom of the blades, working opposite the cutting edge. The blocks can be clamped into position by clamping members 29.

The device 11 also includes a feeding unit 30 which can singularly feed nuts to the unit when the arms 14, 15 are in the nut holding position. The feeder 30 has a hopper 31 to hold nuts 10 to be cracked.

The hopper 31 has a moving false floor 33 located above a stationary actual floor 34.

The false floor 33 is of such size and shape that it can be moved horizontally a prescribed distance within the hopper and always completely cover the actual floor 34. The false floor 33 is pivotally attached to crank arm 17. Movement of crank arm 17 controls movement of both blade arm 15 and false floor 33.

The false floor 33 has a hole 35. The thickness of the false floor 33 and the shape and size of hole 35 are selected such that the hole 35 can receive only a single nut (as shown in Figure Typically, the hole 35 will be slightly larger than the largest nut being handled, and the thickness of floor 33 approximately the same as the average nut.

The actual floor 34 is of such size and shape that the hole 35 in the false floor 33 is always within the boundaries of the actual floor 34. The actual floor 34 has a hole 36 of approximately the same size and shape as the hole 35 in the false floor 33. Hole 36 is located outside the boundaries of the hopper container such that at some point in the movement of the false floor 33 the two holes 35, 36 will become aligned. This is illustrated in Figures 1, 2 and 4.

In operation of the feeder 30, the false floor 33 is moved back and forth by the operation of crank arm 17 such that the hole 35 in the false floor 33 moves in and out of the hopper 31 container and beyond this over the hole 36 in the actual floor 34. As the false floor hole 35 moves in to the hopper container 31, a single nut falls into the cavity created by the false floor hole 33 and the actual floor 34 by random chance. As the false floor 33 moves back out of the hopper container 31 the nut 10 is drawn out with it.

Continuing this movement, as the false and actual floor holes become aligned, the nut 10 drops through the actual floor 34. It can be seen that movement of the blade arm 15 and false floor 33 are synchronized via crank arm 17 such that a nut 10 can only fall through holes 35,36 when the blade arms are in the nut holding position.

The hopper has a flexible flap 38 where the nuts exit the hopper 31. This effectively wipes any extra nuts off the false floor hole 33 as it moves out of the hopper 31, ensuring that in most cases only a single nut exits the system in a given cycle. Also the false floor 33 may need to be rough for some products so that there is enough random movement of the product to ensure that a nut is picked up on most cycles.

In order to modify the timing and position of nuts exiting the system and/or make the mechanism appropriate to other products or devices the relative positions on the hopper, false floor can be adjusted; the shape and size of the false floor hole dimensions and false floor thicknesses changed; and the shape and size of the actual floor changed.

By having different size and shaped holes in the false and actual floors, the timing and positioning of a nut to be cracked can be modified according to it's size. For example a circular hole in the false floor operating over a teardrop shaped hole in the actual floor, will release a small nut sooner at a slightly different position, and vice versa.

A trial was conducted to compare the performance of a nut cracker of the present invention and the industry standard Shaw type crackers. The nut cracker of the invention was observed to cause significantly less damage to the macadamia kernels during the cracking operation than the Shaw type crackers.

There was an increase in whole kernels, typically of at least age units, from approx 45-60% to 60-75%, depending on the characteristics of the batch. Whole kernels have a higher market value, are cheaper to separate from the shells in later processing, and have lower kernel losses in later processing.

Half kernels remained more or less the same, approx 25-40%, depending on the characteristics of the batch.

There was a corresponding reduction of piece and chip kernels, of about 10% age units from approx 15% to depending on the characteristics of the batch. Piece and chip kernels have a lower market value, are more expensive to separate from the shell in later processing, and have higher kernel losses in later processing.

Unrecoverable fine kernel powder was typically reduced from about 3% to Fine kernel powder cannot be economically recovered in later processing.

It can be seen that the device of the present invention allows hard, round nuts such as macadamias to be cracked with minimal kernel damage. This reduction in kernel damage may be attributed to the lack of any trailing surface on the blade arms which can damage the kernel by secondary impact. Having a feeding unit operatively associated with the blade arms allows nuts to be singulated, timed and positioned accurately in the cracker movement. This can reduce or even eliminate "pre-cracking".

"Pre-cracking" is known to occur in the conventional Shaw type cracker when nuts grip and are cracked against the chamber wall before meeting the stationary blade, where it is cracked again, causing significant damage. The feeding unit of the present invention also allows a nut to settle before cracking. On the other hand, in the Shaw type cracker, the rotating blades are always moving and nuts must size instantly. Still further the preferred device of the present invention allows parameters such as blade depth and cracking blade speed to vary depending on the size of the nut. It is possible for smaller nuts to be cracked with smaller movements and at lower speeds then larger nuts. This is the opposite in the Shaw type cracker in which smaller nuts are subjected to the faster speed and greatest movement.

Figures 7 and 8 show a cross sectional view of a rotary version of the device for cracking nuts of the present invention. Figure 7 shows a nut cracking device 50 a stationery housing 51. Peripheral blades 52 are mounted about the inner wall of the housing 51. The peripheral blades 52 are attached to the housing by bolts 53. A rotating shaft 60 is driven by a motor (not shown) the rotating shaft 60 is mounted within the housing 51 by bearings 59. A blade support 61 is mounted for rotation on the shaft 60 and blade 62 is bolted to the blade support 61 by bolts 63. The housing 51 has a fixed upper surface 54 that includes an opening 55. A rotating upper surface 64 is attached to the shaft 60 and includes a corresponding aperture 65 such that when the apertures are aligned nuts may fall into the nut cracking device and be opened as the blades move past each other as described with reference to the embodiment shown in Figures 1 to 6.

Shield 56 prevents nuts from entering the nut cracking device in an uncontrolled manner. The shield 56 is disposed above openings and for nuts to enter the nut cracking device 50 they fall into the opening on the rotating upper surface 64 and pass under the shield 56 through a deformable rubber flap 58 whereabouts they are disposed above aperture and may fall into the nut cracking device.

It will be appreciated that various modifications and changes can be made to the invention as described and claimed herein without departing from the spirit and scope thereof.

Claims (11)

1. A nut cracking device, the device having at least one nut cracking unit, each unit including two opposing blade arms, each blade arm having an inwardly facing cracking blade extending along an edge thereof, the blade arms being movable with respect to each other between a nut holding position in which the nut is held between the blade arms and a nut cracking position in which the blades can engage and crack a nut by a shearing force.

2. The device of claim 1, wherein one blade arm is stationary and the other blade arm is movable.

3. The device of claim 2, wherein the movable arm is mounted for pivotal movement.

4. The device of claim 3, wherein the movable blade arm is substantially vertically aligned and is mounted for pivotal movement at its lower end. The device of any of claims 1 to 4, wherein when in the nut holding position a V shape is defined between the blade arms.

6. The device of any one of claims 1 to 5 which further includes adjusting means for adjusting the depth which the blades extend from the blade arms.

7. The device of claim 6, wherein the length can be adjusted to provide a blade depth profile along the edge of the blade arm.

8. The device of any one of claims 1 to 7 which further includes a nut feeding unit for feeding a nut to be cracked to the unit when the blade arms are in the oooo nut holding position. The device of claim 8, wherein the nut feeding unit is operatively associated with the relative movement of the blade arms. The device of claim 9, wherein the feeding unit includes a base member having a nut release aperture located above the cracking unit such that a nut can pass through the aperture into the cracking unit, a nut storage chamber remote from the aperture and transfer means for transferring a single nut from the storage chamber to the aperture.

11. The device of claim 10, wherein the chamber has a bottom wall, the bottom wall having a nut receiving aperture, the bottom wall is movable between a nut collecting position and a nut release position in which the nut receiving aperture is in alignment with the nut release aperture. 12

12. The device of claim 11, wherein movement of the base wall is timed such that when the blade arms are in the nut cracking position, the base wall is in the nut collecting position and when the blade arms are in the nut holding position, the apertures are aligned so as to release a nut into the unit.

13. The device of any one of claims 10 to 11, wherein the nut release aperture is tear shaped.

14. A dispensing unit when used with the nut cracking device of any one of claims 1-7 for dispensing a nut in a singular manner, the unit having a base member, a dispensing aperture in the base member through which a single nut can be dispensed, a nut storage chamber, remote from the aperture, the chamber having a bottom wall, a nut receiving aperture located in the bottom wall, means for moving the bottom wall between a nut collecting position in which the receiving aperture is located within the chamber and a nut dispensing position in which the receiving and dispensing apertures are aligned such that a nut can pass therethrough. Bell Cracking Pty Ltd By their Patent Attorneys CULLEN CO