GB2290695A - Shelling cashew nuts - Google Patents

Abstract

The appts. to shell nuts, and especially cashew nuts, advances the blade assembly (4) in two successive movement phases. A first step gives movement according to the size of the nut to bring the blades (26, 27') against it. The second step is for a fixed length for the cutting action to cut the nut (10) open. During the two movement steps, the blade head (25, 25') adopts the cutting setting and is moved into the separation setting before or at the end of the cutting phase.

Description

2290695 A Device for opening Nuts The invention relates to a device for

opening nuts, and more particularly but not exclusively for opening cashew nuts, comprising a holding means, adapted to detachably hold therein a nut to be opened in a ready to be opened position, a knife arrangement, advancing means on which said knife arrangement is mounted and which is adapted to drive the knife arrangement in an advancing movement toward said holding means in order to cut into the shell of a nut located in the ready to be opened position.

The processing of cashew nuts represents a substantial branch of industry in many countries. This is because practically all components of such nuts find some form of useful application. The kernel of the nut is as a rule consumed and is much appreciated for its taste. Nut oil is extracted from the shell. Furthermore the skin surrounding it is in many cases separately utilized.

So far cashew nuts have been manually cracked by using a knife arrangement to cut into a suture in the nut shell and then using some form of tool to part the shell halves from the nut kernel. This work is very tedious and slow, since normally sorting into different size grades is necessary. Furthermore, the kernel is frequently damaged by the cutting tools and may hence not be put on the market as being oil prime quality.

The present invention consequently has the object of creating a device for opening nuts, more particularly cashew nuts, with which nuts for various different sizes may be opened with a considerably reduced danger of damage for the kernel.

In order to attain this or other objects in accordance with the invention the knife arranaement comprises two knife heads each having at least one arcuate knife and which are adapted to be moved between a cutting position and a parting;position, the knives being in the cutting position essentially in a common cutting plane and at least one knife being arranged 3, 0 clear of the cutting plane in the parting position and furthermore the advancing movement of the knife arrangement is divided nto two consecutive phases including a probing phase with a variable probing advancing stroke, dependent on the size of the nut, as far as engagement of the knives on the nut located in the ready to be opened position, and an incision phase following the prcbing phase, with a predetermined incising advance stroke 1 independent from the probing advance stroke, the knife heads assuming the cutting position during the probing phase and the incision phase and toward the end or after conclusion of the incision phase are moved into the parting position.

This provides for a reliable opening of nuts and more particularly of cashew nuts, without a pre-sorting thereof in accordance with size and form being necessary, since there is an automatic adaptation to the particular circumstances. The essential reason for this is the two-stage advance motion of the knife arrangement. In a first phase of motion termed the probing phase, the knife heads loc-ated in the incising position are advanced so far that their knives arranged 'in a common plane engage the respective nut which is in the ready to be opened position. The distance then moved through, referred to herein as the probing advance stroke, is dependent on the configuration and size of the respective nut. in the case of a large nut the probing advance stroke will be smaller than in the case of' a relatively small nut. In any case the in the course of the probing phase the knives will be always set against the nut shell so that the nut is practically "explored" by probing it. It is only when the probing phase is concluded that the actual opening operation is commenced. For this purpose the knives are caused to cut or bite into the nut a predetermined amount, hereinafter rez-erred to as the incision advance stroke. This phase oil motion is termed the incision phase. The incision advance stroke is as a rule made dependent on the mean shell thickness typical for the nuts in question, in the case of cashew nuts an incision advance stroke in the order of approximately 2.5 mm having been found accepta'kj"ie. This represents an amount of cut, which falls short of incision through the full thickness of the nutshell so that the kernel of the nut or the skin surrounding it is not damaged. Once the incision phase is completed, the knife heads are moved out from the cutting position into the parting position, something which for example may be caused by a spreading apart -zthwai--L the direction of the advance, so that the shell halves are parted and the kerne] is uncovered. After this the knife arrangement is moved backed into the starting position in order to repeat the opening operation on the: nex-1 nut moved into the ready to be opened position.

c,::ut-L,hz-r advantageous developments c-,;: the invention are defined in the claims.

it -;:'c, the advance means to csnpr-;--e a pneumatically is convenjent, 1 ' A- operated po-wer cylinder, which in a comparatively simple fashion renders possible Vhe detection the and ci: the probing phase. It i S sufficient to detect. pressure in the doqns-.rea,,n cylinder chamber using a con,jent-ion-;].:ressure sensor, a sharp drop in pressure being 2 an indication that the advance motion has been interrupted by the engagement between the knife and the nut.

During the final part of the probing phase then it is convenient to reduce the advancing force acting on the knife arrangement so that on engagement with the nut the knives either do not, or only hardly, cut into the nut. It is only when the contact with the nut is established and the probing phase is completed that the advancing force is increased in order to permit easy cutting into the nut shell the desired amount. The use of a power cylinder renders it possible for the advance force to be set without any problems by varying the supply pressure.

In order to optimize the adaptation of the knife arrangement to suit the respective nut to be opened, it is an advantage for each knife head with a knife arranged thereon to be able to be pivoted about an axis extending perpendicularly to the plane of cutting and to be preferably spring biased into a basic position. The arcuate knives may then suitably align themselves in the course of engagement with the nut in accordance with the curvature of the nutshell.

It is furthermore an advantage if knives of the two knife heads, as seen in the cutting position, are arranged essentially on a common arc in sequence so that they do not mutually flank each other. Accordingly it is possible to prevent' clogging of the space between the knives. The knives may return into the original position after each opening operation in which they are in the cutting plane so that each nut is reliably cut at the desired point.

For optimum arrangement of a respective nut in the ready to be opened position, it is to be recommended to provide the holding device with respectively two pairs of long holding springs like strip springs and short centering springs like strip springs, it being convenient if one respective pair of centering springs is arranged within a pair of holding springs. The inserted nut may be so seated on the centering springs and held by the holding springs. Even for the initial engagement of the knives with the nut a suitable configuration of the springs will facilitate attaining the desired alignment.

It is furthermore convenient to arrange an additional stationary knife at the holding means, which is opposite to the knives located in the cutting Dosition. It is in this manner that the nut is cut as the movable knives bite on the other side as well, something which facilitates the operation of parting the halves of the nut shell.

In what follows the invention will be described with reference to the accompanying drawings.

3 Figure 1 shows a first constructional form of the apparatus in accordance with the invention taking as an example a design for opening cashew nuts.

Figure 2 is a view of part c-IF the apparatus in accordance with figure 1 looking in the direction of the arrow II, the continuous lines indicating the cutting position and the chained lines denoting the parting position of the knife heads.

Figure 3 is a view of a holding means on an enlarged scale as seen from the front looking in the direction of the arrow 111 in figure 1.

Figure 4 is a lateral elevation of the holding means of figure 3 locking in the direction of the arrow IV.

Figure 5 is view of part of the arrangement of figure 1 on a larger scale adjacent to the setting means for the starting point. of the cutting phase.

The apparatus illustrated by way of example comprises an advancing means 2 secured to a holder 1 and having a linearly moving output drive part 2 5 3 on which a knife holder arrangement 4 is mounted. Furthermore, in the present example, a positioning means 5 is provided, constituted by a turret plate, and on which a plurality of holding means 6 is mounted, which may be shifted one after the other into a working position 8 as indicated by the arrow 7. The shifting action is performed for example by rotation of the turret plate.

There is furthermore a control means 9, which control the movement cycles of the apparatus in a manner yet to be described.

The advancing means 2 includes, in the present working embodiment, a double acting pneumatic power cylinder 12, which possesses a housing 13, in 3 5 which a piston 14 is arranged so that it can run ",n the axial direction. A continuous piston rod 15 is attached to the piston 14, and -; it extends through the housing 13 in the axial direction, its two ends extending out from the housing 13. The piston rod 15 belongs to the output drive part 3, which in the working embodiment furthermore possesses a suroort pl-ate 16, which is so secured at the end to the right, in term.s of figure 1, of the piston rod 15 4 that the plane of its plate is at a right angle to the longitudinal axis of the piston rod 15. To prevent twisting and for support two guide rods 17 and 17', which extend in parallelism to the piston rod 15, are provided, which extend to the side of the housing 13 and run in a guide means 18, secured to the housing, for axial sliding motion. The housing 13 is secured with the aid of guide means 18 on the holder 1. For this purpose the guide means 18 may have a U-like con-Figuration and may be secured on the end near the support plate 16, of the housing 3, the one guide limb 22 being secured to the holder 1.

Two spaced, further support plates 23 and 23' (of the output drive part 3) extend axially from the support plate 16 in a direction away from the housing 13 and a knife arrangement 4 is arranged on them.

The knife arrangement 4 comprises two knife heads 25 and 25' which in terms of the position of use of the apparatus are superposed. On each knife head 25 and 25' an arcuate knife 26 and 26 is attached in such a manner that such two knives 26 and 26' are in a common plane, to be named the cutting plane 28 in the cutting position, indicated in continuous lines in figure 2, of the two knives 26 and 26'. The two knives 26 and 26' are in this respect not arranged to flank each other but rather lie one after the other in the direction of the extent on a common arcuate line 32 as shown in chained lines in figure 1. 7he longitudinal extent in the example of the two knives 26 and 25' amounts in each case to approximately one quarter of the circular arc so that, in the indicated cutting position the knives complement' each other to represent about half a circle.

it will be clear that the two knives 26 and 26' are not necessarily designed in the fashion depicted consisting of a single knife element and in fact they may well be composed of a plurality of individual knives.

The cutting edges 33 of the knives 26 and 26' are located on the concave sides thereof, that is to say on the side directed toward the center 3 t point of the radius, the knives 26 and 26' being so arranged that the cuLting edges 35 point axially away from the power cylinder 12 and face The holding device 6 which is respectively in the working position 8 and are opposite thereto in the direction opposite to the direction 34 of advance of the knife arrangement 4.

The advancing direction 34 defines the direct-Ion, in which the knife arrangement 4 is able to be moved by the advancing device 2 in order to be shifted from a basic position, which is further removed from t-he holding device 6, into a working position nearer to the holding device 6. The advancing direction 35 coincides with the longitudinal direction of the power +0 cylinder 12.

The two knife heads 25 and 25' are respectively arranged on a support arm 35 and 35', which is pivoted on the above mentioned further support plates 23 and 23'. The two support arms 35 and 55' are, as seen in plan view in accordance with figure 2, arranged to the side of each other. A part of the length thereof is located in the intermediate space 36 between the two further support plates 23 and 23', whereas the other part projects on the side, opposite to the support plate 16, from the intermediate space 36 toward the holding device 6, which is in the working position 8. The knife heads 25 and 25' are arranged on the projecting terminal parts of the support arms 35 and 35'.

The pivot axes for the two pivotally mounted support arms 35 and 35' extend in parallelism to the plane 28 of cutting and simultaneously more particularly at a right angle to the direction.34 of advance.

Each support arm 35 and 35' is engaged by a servo member 38 and 38' which is arranged on the output drive part 3 in order to be able to cause a pivotal motion, as indicated by the double arrows 42 and 42', of the support arms 35 and 35' around the pivotal axes 37 and 37'. The points 43 and 43' of engagement between the servo members 38 and 38' on the one hand and the support arms 35 and 35' on the other hand are preferably located on those sections of the support arms, which, with reference to the, pivot axes 37 and 37', are on the side facing the power cylinder 12. In the working embodiment of the invention the servo members 38 and 38' are constituted by pneumatic power cylinders of the short stroke type, which together with theirs housings are pivotally mounted on the two further support plates 23 and 23', the pivot axes of the corresponding pivot points 40 and 40' being parallel to the pivot axes 37 and 37' of the pivot points for the support arms 35 and 35'. By actuation of the servo members 38 and G8' it is accordingly possible to shift 't.lie knife heads 25 and 25' as indicated by the double arrows 42 and 40' out from the illustrated cutting position 27 into a cutting or parting position 41 shown in chained lines and back again. In the parting position the knives 26 and 26' of the two knife heads 25 and 25' are clear of the above mentioned cutting plane 28 and are so pivoted out of the cutting plane 28 that they assume posit-ions on opposite sides of the cutting plane 28 (see figure 2).

In order to open a nut, firstly a holding device 6 with the nut therein is moved into the working position 8. The position then assumed by the nut 10 is termed the ready to be opened position. The knife arrangement 4 is as yet in the basic position, in which it is withdrawn back opposite to the direction 34 of advance and is arranged at a fair distance from the said holding device 5. The support arms -35 and 35' are not yet pivoted so that the knives H and 26' have their cutting edges 33 in the cutting plane 28.

6 By the supply of driving fluid into the cylinder chamber 44 on the feed side and nearer to the rear piston rod section 24, of the power cylinder 12 via an associated fluid line 44' the output drive part 'i is shifted in the advancing direction 34 so that the knives 26 and 26' moved toward the nut 10 located in the ready to be opened position. The phase of the stroke between the basic position and the engagement of tine knives 26 and 26' with the nut 10 is to be termed the probing phase. The probing advance stroke covered by the knives 26 and 26' during the probing phase is not permanently set and will be dependent on the size and/or configuration of the nut 10 located in the ready to be opened position. In the case of a nut with a fair size tine probing advancing stroke is naturally less than in the case of a small nut.

The probing phase practically serves to set the zero point or initial point for the nut opening operation as such, in which the knives 26 and 26' are caused to bite or cut into the nut shell a certain extent. This biting or cutting action takes place following the probing phase and will be termed the incision phase, the stroke movement of the knives 26 and 26' being termed the incision advancing movement. Whereas the probing advancing movement may vary from nut to nut so that it is automatically adapted to the particular circumstances of the case in hand, the size of the incision advancing movement is predetermined by external factors and remains the same during opening process. It is a matter of empirical testing and can be set as a preliminary prior to putting apparatus into se in accordance with the type of nut in question in a manner yet to be explained.

As an indicator that 'Line end of the probing phase has be-en reached in tine present working embodiment use is made of the drop in pressure taking Place at -Line end of the advancing motion of the piston 14 in the downstream output or downstream cylinder chamber 45. For this purpose the output cylinder chamber 45 or the pressure line 45' connected with it, is connected with a pressure sensor, not illustrated in detail, which belongs to the control device 9.

In order to avoid any spurious values being produced -For the initial position for the incision phase, 'Line knives 26 and 26' are thrust in the probing phase with mereqy a relatively low force against the shell of the nut 10. This takes place by reducing the working pressure, normally obtaining -,.5 -in the upstream cylinder chamber 44 - of for instance 5 bar - to - 1or example 1.5 bar, at least during the terminal part of the probing phase. This reduction in pressure can be predetermined using the control device 9 to be dependent on displacement and/or time. Preferably a higher pressure, and consequently a higher velocity of displacement, will be selected at the start D of the probing phase than at the estimated end of the probing phase so that 7 at the end of the probing phase the knives will at the most only have cut a slight extent into the nut shell.

When, the ncision phase is terminated, this implying that the knives 26 and 26' have been moved back by -he predetermined incision advance distance or movement and have bitten or cut into the nutshell, the control device 9 is responsible 1For the switching over of the knife heads 25 and 25' out from the cutting position '27 into the parting position 41, the knives, which have penetrated into the nut shell, prying open the shell. This prying action is facilitated if those nuts whose shells have a suture 26 extending at least substantially completely about them, are aligned so that the suture 46 is in -Che plane 28 c-ic cutting in the ready to be opened position. The knives 26 and 26' are then able to bite into the nut adjacent to the suture 46 and open the nut with a comparatively small application of force.

in order to aid the opening operation, it may be an advantage to provide a stationary knife 47 on a respective holding device 6 in addition to the moving knives 26 and 26' of the knife arrangement. The alignment thereof is preferably such, as illustrated, that it. or, respectively, its cutting edge is in the cutting plane 28 and consequently in the same plane as the moving knives 26 and 26'.

The configuration of the stationary knife 47 is preferably adapted to the profile of the type of nut to be opened. For the opening of cashew nuts it is to be recommended to adopt a contour of the cutting edge depicted in figure 4, which has a similarity to a letter W, since nuts possessing this kidneyshap.ed configuration are most expediently so arranged in the holding device 6 that the grooved part thereof faces the direction 34 of advance and the floor of the holding device 6, adjacent to which the stationary knife 47 is secured The nuts 10 to be opened can be mechanically or manually placed in the holding devices 6. Whereas;the utilizaton of a positioning device 5 with 3 0 a multi,nl-:icty of holding devices will - in the present context - permit the processing cf larger numbers of nuts, it would be feasible as well to provide but a single holding device 6, which however would then certainly be able to be pivo-Lm-d between the depicted working position 8 and a nut insertion position in order to facilitate the of the nut, which is to be 3 5 opened, -herein.

For -r-ne Preliminary setting ciF --heincision advance movement or distance, the user is best guided by mean thickness of the type of nut Lo be c:=-n=-d. The Setting should in -.r"Is respect be so selected that the depth of penetration or, respectively, of incision is less than the 0 'hick-.necs of ne shell. E',,en i.;7 the shell is not completely cut through by the knives, it can be readily pried open by the knives Moving into the parting position.

Once the moving knives 26 and 26' are in their parting position so that the nutshell has been pried or torn open, the knife arrangement s retracted in the basic position by movement opposite to the advance direction 34. Even during the withdrawing movement it is possible for the knife heads 25 and 25' to be moved back into the cutting position.

For an even greater improvement in the ability of the knives 26 and 25' to adapt themselves, more particularly to the configuration of the respective nut to be opened, the knife heads 25 and 25' of the present working embodiment mounted on the respective support arm 35 and 35' so that they can be pivoted as indicated by the double arrows 49 and 49', the pivot axes 48 and 48' extending at a right angle to the plane 28 of cutting as seen in the cutting position. Owing to contact wich the external surface of the nut !5 shell the knives are consequently able to move into an optimum position in relation to a shell by pivoting independently of each other. Preferably the knife heads 25 and 25' are resiliently urged into a basic position as indicated in figure 1, in which the intermediate space between the two knives 26 and '2116 has a maximum value. The knife heads 25 and 25' are more particularly held by springs 52, which engage the knife on the one hand and on the other hand the associated support arm 315 or 35'. The basic position is set by an abutment 53 secured to the support arm. On contacting the nut the knives 26 and 216' can be shifted in relation to one another in such a manner th-at the intermediate space located between them and consequently the arc radius defined by them will be reduced in si-7e.

in the working embodiment of the Invention each knife head 25 and 25' comprises a knife 26 and 26' and a knife carrier 54 and 54' bearing the same and more particularly of a platle-like configuration, such carrier being pivoted on the associated support arms 35 and 35' and engaged by the return spring 52 for it urging the same into the basic setting.

Within the rear piston rod section 24, which is outside the housing 3, an adjus-Lment device is provided, which renders possible a reliable setting of the initial pcs-'jtioh, which is relevant for the start of the incision phase of the knife arrangement 4. The structure illustrated by way of ::5 e->.ampe nl,-.zsesses a step 55 on the rear piston rod section 24, which 'Is adjoined '-y a terminal section 56, which runs out toward the end, of 'he piston rod 15 whose diameter is reduced to be less than the adjo-;lnna section. A substantially sleeve-like abutment part 57 is mounted coaxialy on --=-,-minal sect-;,on 5, and it is able to be moved axialy in relation "0 to the -errinal or end section 5P.. The abutment part 57 is biased by means L- 9 of a spring arrangement 58 axially in the advance direction 34 and hence in the direction of the step 55. Should the output drive part 3 be located in:-he basic position depicted in figure 1, then the abutment part 57 will contact the step 55. The position of contact will in the following be referred to as the initial postirn as it appears in figure 1.

Furthermore a stroke delimiting part 552 is mounted on the terminal section 56, which bears against a setting nut 63 screwed on a thread on the terminal section 55 so that it is prevented from moving opposite to the advance direction 34. The spring arrangement.58 bears axially against the abutment part 57 and the stroike delimiting part 62, the latter having a belllike form in the present example and overlapping the abutment part 57 radially outward for a certain axial extent.

The abutment part 57 is able to be pivoted out of position by the application of -&Force, the return force of the spring arrangement 58 being overcome, against the advance direction 34 until it assumes a terminal position as shown in chained lines in figure 5 abutting against the stroke delimiting part 62. The end position is indicated in figure 5.

The adjustment device 21 furtherniore comprises a locking part 64, which in the working embodiment is wedge-like. The locking part 64 is located in the portion which is axially between the housing 13 of the power cylinder 12 and the abutment part 57, it assuming the non-ac.1king position indicated in figure in the basic position of the output drive part 3, in which position it is arranged c]=-ar c-&;-' the position axia stroke of the abutment part 57. The non-acting position is as shown in chained lines in figure 5. A servo member 65 engages the locking part 64, such servo member being in the present example a pneumatic power cylinder designed to provide a short stroke and being secured on the housing 13. The locking part, 64 is borne by the piston rod of the servo member 65. Ey operation of the servo member 65 it is possible to shift the ocking part 64 out from the illustrated inactive position into a locking position depic-ed in figure 5, in which it is within the axial pat-in of the abutment-, part 67. The setting direction of the locking part 64 is preferably at a right angle to the advance direction 34. The locking part 64 is so arranged zhat its one wedge surface faces the abutment part 57 and may bear against cppcsit.Ia rear wedge surface 61 on the end surface of the housing 13.

if now the advance deviCe 2 is in basic position, the locking part 9,4 will assj.-ne its non-acli-.ing in the following probing phase the cutPut di-i,;e Plart- 3 will rnove In the -ndvance direction 34, the abutment part 57 and the stroke delimiting Dart 52 being shifted as well. The axial distance the P-r-rt -.'7 and the locking part 64 assuming the i3 non-acting position is greater than the maximum possible probing advancing stroke so that short of the end of the probing phase there can be no contact between the abutment part 57 and the locking part 64.

After the end of the probing phase, which is sensed by the reduction in the pressure in the downstream cylinder chamber 45, the servo member 65 is operated so that the locking part 64 is moved at a rigliT- angle to the advance direction -,4 and arrives in the locking position. The locking position is reached when the wedge surface 66 bears against an abutment surface 67, directed in the direction 34 of advance, of the abutment part 57.

Since the locking part 64 is held stationary by the engagement of its rear surface 61, the abutment part 57 is hindered from moving farther in the advance direction 34. The setting force of the locking part 64 is less than the return force of the spring arrangement 58 so that the locking part 64 itself is not in a position to deflect the abutment part 57 out from the initial position.

Once the locking part 64 is in the locking position, the incision phase is commenced. This is done, as above mentioned, with a higher setting force than in the probing phase, the setting force being so great that the return lorce of the spring arrangement 58 can be overridden. As aconsequence it is possible For the piston rod 58 and accordingly the output drive part 3 to be shifted in the advance direction 34 until the stroke delimiting part 62 runs up against the abutment part 57 (as shown in chained lines in figure 5). in this case there will be a relative displacement between the piston rod 15 and the abutment part 57, in the case of the abutment part 57 will shift from the initial position into the terminal position.

As will be apparent the movement or path marked a in the figure between the initial position and the terminal position of the abutment part 57 is the same the size of the incision advance stroke. By changing the preset for the movement a, it is therefore possible to affect the preset for the incision advance path.

in the present example an adjustable preset for the movement a is possible by modifying the relative movement between the stroke delimiting parz 62 and the piston 'rod 15. It is merely necessary to screw the setting nut 64, which acts on the stroke delimiting part 62, to a greater or lesser 215 ex-Lent onto the piston rod 15. The stroke delimiting part 62 itself is hed by the force of the spring arrangement 58 in the abutment position on the seiting nut 63.

After the end of 'lie incision phase the knife heads 25 and 25' are switched over into the parting position as above mentioned. The signal For this to be done is provided, in the illustrated working embodiment, by a 11 sensor 68 mounted on the adjustment device and which preferably is constituted by a back pressure nozZle 69. The back pressure nozzle 69 is switched into the active state at the start of an incision phase so that it blows compressed air. At the end of the incision phase the back pressure nozzle 69, which in the illustrated embodiment is provided on the stroke del Imiting part 62, is covered over by the surface of the opposite part, in the present case of the abutment part 57. The resulting increase in pressure constitutes the switching signal for causing the parting operation to take place at the knife arrangement 4.

Simultaneously with the prying open of the nut by the lever mechanism operating in the opposite direction, it is convenient for air to be blown at the site of action of the knives 26 and 26' through a nozzle 72, such air protecting the moving parts from being fouled up.

Since the locking part 64 is able to steplessly set each end point of the probing phase, there 'Is a high degree o-IF certainty that the depth of the penetration of the knives 26 and 26' will be within the permissible range and that the nut kernel will not be damaged.

All relevant devices and sensors of the apparatus given by way of example are connected with the control device 9, which is only indicated diagrammatically and which coordinates and controls the sequential performance of the individual working phases.

in order to ensure a reliable alignment of a given nut 10 in the ready to be opened position, the holding device 6 is in the example provided with an arrangement of strip-like springs, which center the inserted nut 10 and fix the same. As regards details it is a question of two pairs of holding -spring 73 and 73', which are spaced apart opposite one ancther. Each holding spring 73 and 73' has its one end 74 secured to the floor 75 of the holding device 6, which also bears the stationary knife 47. The opposite spring ends 76, which in the working position 8, face the knife arrangement 4, are free.

The two holding springs 73 and 73' of each pair of spring assume positions on opposite sides of the zutIiig plane 28, the h:)1d-i,ng spring 703 and 73' respectively on the same side preferably being at least substantially in a cc mm on p 1 --- n e. Starting at the f toor 75 the holding springs 73 and 73' -Firstly ossess a more or less stralgint but- slightly outwardly curved -5 section, is followed by a hurnpliP-.e ble-nd, each sPring firstly extending outward and then back inward again, this bsing followed by an Outwardly bent terminal section.

7he intermediate space 77 Present, between a resPective pai r 73 and 73 of holding springs accordingly firstly becomes wider from the floor 75 and has it wic:T-h in the hijrip-l 1 P,e bend sect-;1c.n, whence it becomes narrower again toward the curved end section in order to then to become wider again and therefore to favor the yielding insertion of the nut 10 in position.

In each of the two intermediate spaces 77 between spring there is a 5 further pair of springs constituted by two centering springs 78 and 78'. They are, like the holding spring 73 and 73', secured at one end on the floor 75 and free at the other end. They are however shorter than the holding springs 73 and 73', their free ends 82 extending generally as far as the part where the width of the intermediate space is minimum. The configuration in the longitudinal direction is also curved and/or bent, there being a bend in an inward direction near the floor, this being adjoined by an outwardly and upwardly extent support part 83. When inserted a nut 10 is below borne on the support parts 83 and at the top is partly overlapped by the terminal sections of the holding springs 73 and 73'. Since all springs can be resiliently bent independently from each other, a respective nut 10 will be automatically centered and aligned on being inserted. On breaking open a nut 10 the holding springs 73 and 73' are spread apart so that the shell halves are able to drop out.

13

Claims (27)

Claims

1. A device for opening nuts, and more particularly but not exclusively for opening cashew nuts, comprising a holding means, adapted to releasably hold therein a nut to be opened in a ready to be opened position, a knife arrangement, advancing means on which said knife arrangement is mounted and which is adapted to drive the knife arrangement in an advancing movement toward said holding means in order to cut into the shell of a nut located in the ready to be opened position, the knife arrangement comprising two knife heads each having at least one arcuate knife and which are adapted to be moved between a cutting position and a parting position, the knives being in the cutting position essentially in a common cutting plane and at least one knife being arranged clear of the cutting plane in the parting position, the advancing movement of the knife arrangement being divided into two consecutive phases including a probing phase with a variable probing advancing stroke, dependent on the size of the nut, as far as engagement of the knives on the nut located in the ready to be opened position, and an incision phase following the probing phase, with a predetermined incising advance stroke independent from the probing advance stroke, the knife heads assuming the cutting position during the probing phase and the incision phase and toward the end or after conclusion of the incision phase are moved into the parting position.

2. The device as claimed in claim 1, characterized in that the advance device comprises a fluid power and more particularly pneumatic power cylinder.

3. The device as claimed in claim 2, characterized in that as an indicator for reaching the engagement, predetermining the end of the probing phase, between the knives and the nut, the pressure reduction taking place 14 in the downstream side cylinder chamber of the power cylinder is utilized.

4. The device as claimed in any one of the claims 1 through 3, characterized in that the advancing force exerted by the advancing device on the knife arrangement is less, at least during the terminal phase of the 5 probing phase, than the following incision phase.

5. The device as claimed in any one of the claims 2 through 4, characterized in that the respective advancing force is preset by the pressure in the power cylinder.

6. The device as claimed in any one of the claims 1 through 5, characterized in that the advancing device comprises a linearly moving liquid drive part connected with the knife arrangement and on which an abutment part is so arranged that it is able to be moved in relation to the output drive part between a starting position and a terminal position, the abutment part being biased in the advancing direction toward the starting position and is able to be set, while overcoming a return force, against the advancing direction as far as reaching the terminal position, in which it engages a stroke delimiting part connected with the output drive part for movement therewith, the preset between the starting position and the terminal position corresponding to the desired incision advance stroke and in a locking part is provided on the side of the abutment facing in the advance direction, into the path thereof in order to prevent the abutment part form moving further in the advancing direction after the end of the probing phase.

7. The device as claimed in claim 6, characterized in that the stroke delimiting part is connected with the output drive part in a linearly adjustable manner for variably predetermining the terminal position of the abutment part.

8. The device as claimed in claim 6 or claim 7, characterized in that the locking part is a wedge-like part extending transversely in relation to zhe advance direction and which after the termination of the probing phase 31 0 is adapted to move so far into the path of motion of the abutment part that 'Its wedge surface engages the abutment part.

9. The device as claimed in any one of the claims 6 through 8, characterized in that a sensor is present, which, when the terminal position of the abutment part is reached, provides a switching signal, on the basis of which the knife heads are moved from the cutting position into the parting position.

10. The device as claimed in claim 9, characterized in that the sensor is a back pressure nozzle mounted on the abutment part or on the stroke delimiting part and which is arranged to be covered over in the terminal position by the part opposite to it.

11. The device as claimed in any one of the claims 1 through 10, characterized in that each knife head is connected with the output drive part of the advancing device for pivoting about an axis at a right angle to the plane of cutting, it being preferably biased resiliently into a basic position.

12. The device as claimed in any one of Che claims 1 through 11, characterized in that the knives of the two knife heads, as seen in the cutting position, are on a common arc and one after the other.

is

13. The device as claimed in claim 12, characterized in that the two knives respectively possess an arcuate length approximately equal to a quarter of a circle and in the cutting position complement each other to give an arcuate length approximately equal to a semicircle.

14. The device as claimed in any one of the claims 1 through 13, characterized in that each knife head is arranged on a support arm, which is able to be pivoted around a pivot axis extending in parallelism to the plane of cutting and is connected with the output drive part of the advance device.

15. The device as claimed in claim 14, characterized in that each support arm is engaged by a servo member, which is mounted on the output drive part, and is able to be pivoted with the support arm in order to shift the knife heads between the cutting position and the parting position.

16. The device as claimed in claim 14 or in claim 15, characterized in that knives of -khe two knife heads are arranced on either side of the plane of cutting in the parting position.

17. The device as c7a.:1r,-,ed in any one of the claims 1 through 16, characterized by a stationary knife arranged on the holding device and extending 'in the cutting plane, such kni-Fe being opposite the knives of the is knife heads, when such knives assume the cutting position.

18. The device as claimed in claim 17, characterized in that the stationary knife has a W-like cutting edge shape for the opening of cashew nuts.

19. The device as claimed in any one of the claims 1 through 18, characterized by two pairs of mutually opposite and more particularly strip like holding springs on the holding device, between which the nut in the ready to be opened position is resiliently held and which are secured at one end and at the other end are free, such springs having a curved and/or bent form in the longitudinal direction.

20. The device as claimed in claim 19, characterized by a pair of striplike centering springs arranged in the intermediate space between each pair of holding springs, such springs being held at one end and free at the other end thereof and being shorter than the holding springs and being curved and/or bent in the longitudinal direction for the nut to be opened to be supported thereon in the ready to be opened position thereof.

21. The device as claimed in any one of the claims 1 through 20, characterized by a plurality of holding devices, more particularly arranged on a turret plate and which may be moved consecutively into a working position, in which the respectively held nut assumes said ready to be opened position thereof.

22. The device as claimed in any one of the claims 1 through 21, characterized in that nuts whose shell has an encircling suture are so aligned in the ready to be opened position that the suture extends at least substantially in the plane of cutting.

23. The device as claimed in any one of the claims 1 through 22, characterized in that the incision advance path is directed in accordance with the mean thickness of the type of nut to be opened.

24. The device as claimed in any one of the claims 1 through 23, Do characterized in that the incision advance path is smaller than the shell thickness normally occurring with the type of nut to be opened.

The device as claimed in any one of the claims 1 through 24, 17 characterized by a nozzle, which when the knife heads are in the parting position, is adapted to blow into the intermediate space between the same and the against associated holding device.

26. A device for opening nuts substantially as hereinbefore described with reference to the accompanying drawings.

27. Any novel subject matter or combination including novel subject matter disclosed in the foregoing specification or claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.