GB2199731A - Apparatus for slicing fruit, vegetables or the like - Google Patents

Abstract

A fruit-slicing machine (11) has a plurality of rotary slitting blades (42) spaced axially by a distance corresponding to the thickness of the slices of the fruit to be formed; at least one holder (27) for fruit items having a plurality of slots spaced by the same distance as the separation between the rotary slitting blades (42) and conveyor means (10, 24) for conveying the fruit holder (27) beneath the said slitting blades (42) with the said slots in alignment with the blades (42) whereby to slice a fruit item into a plurality of slices upon a single pass through the said rotary blades (42). <IMAGE>

Description

Apparatus for slicing fruit, vegetables or the like The present invention relates to apparatus for slicing fruit, vegetables or the like, by which term is meant any food item containing juice or liquids and being of a relativ#ely soft or pulpy composition such as to make its surrounding environment damp or sticky with juice or other liquid upon rupture of a skin.

The technical problem on which the present invention is based is that of adequately supporting fruit or vegetable items whilst being subjected to the stresses of slicing. Sliced fruit is required in many applications, for decorative and alimentary purposes, and conventionally fruit slicing is effected by hand using hand-held knives, because of the difficulty of retaining the fruit in shape gently, without bruising or damaging it, whilst slicing. Moreover, by slicing fruit manually the problem of juice leaking from the fruit after slicing can be dealt with relatively easily since slicing can be performed on an otherwise flat surface which can be wiped clean periodically.There is also the problem of handling the fruit slices after each fruit item has been sliced, one disadvantage of manual slicing lies in the fact that each individual slice becomes separated from the main body of the fruit and requires separate handling.

Another disadvantage of the known manual slicing techniques lies in the relatively low productivity and high labour content of the work which makes sliced fruit rather an expensive commodity.

The present invention seeks, therefore, to provide fruit slicing apparatus, capable of slicing any item of fruit, vegetable or other food item liable to deformation upon pressure and/or to the leakage of juice or other fluids upon slicing, which is capable of slicing many fruits at a high working rate in an economic manner and with a high degree of technical reliability.

The present invention also seeks to provide such apparatus which, by starting from readily available materials and using known manufacturing techniques, makes it possible to provide a slicing machine economically which, moreover, will offer the highest degree of safety and security in use, even whilst operating at a high speed.

As far as the safety aspect is concerned, not only is it important to take into consideration operator safety during use of the machine, but also safety against contamination entering the fruit and possibly causing food poisoning, botulism etcetera. For this reason the present invention provides apparatus which can easily be maintained in a clean and, if necessary, sterile state whereby to offer a high degree of cleanliness and security.

As used hereinafter, the term "fruit slicing machine" will be understood to relate to a machine capable of slicing any fruit, vegetable or other food item having the characteristics and qualities referred to above.

According to the present invention, therefore, there is provided a fruit slicing machine comprising a plurality of rotary blades spaced axially by a distance corresponding to the thickness of the slices of fruit to be formed thereby, at least one holder for fruit items, having a plurality of slots spaced by the same distance as the separation between the said rotary blades, and conveyor means for conveying the said fruit holder beneath the array of blades with the said slots in alignment with the blades, thereby to slice a fruit item into a plurality of slices upon a single pass through the said rotary blades.

By ensuring that the holder conveys the fruit item beneath the array of blades it is ensured that any juice or other fruit or vegetable fluid escaping from the fruit during slicing will fall away from the blades and the holder, and can be collected in an underlying receptacle which can be periodically emptied and/or wiped clean.

In the preferred embodiment of the invention the fruit holder has a recess in the upper surface thereof and the conveyor carries it past the array of blades in such a way that the blades enter the slots even at the lowermost part of the recess. This ensures that the whole of each fruit item housed in the recess is contacted by a blade during the slicing pass so that each slice is cleanly separated entirely from the others.

The drive for the conveyor is arranged, in relation to that for the rotary blades, such that the fruit is carried towards the edge of the blades which is travelling downwards on the approach side.

That is, the leading edge of the blades is on that part of its circumferential path where it is moving from the uppermost point towards the lowermost point of the blade so that the cutting pressures applied to the fruit tend to press it downwardly into the recess. In order to ensure that the fruit is retained in the recess during the cutting process there may further be provided a comb of guide rods or bars positioned just above the path of the fruit and extending between the slicing blades.These guide rods or bars have a diameter which is slightly less than the separation between the blades and they act to retain the fruit in position during slicing, preventing escape, even of slices, after having passed the blades when the trailing edge of the blade acts on the fruit: it will be appreciated that the trailing edge will be travelling upwards from its lowest point towards it highest point and would therefore exert a lifting force on the fruit slices which, being smaller and of less mass than the fruit as a whole, may tend to become dislodged and/or thrown off the conveyor by such force. The guide rods or bars preferably extend for a sufficient distance on the downstream side of the cutter blades to ensure that the whole of the fruit has moved out of contact with the blades before the fruit is carried out of contact with the guide bars or rods.

The blades themselves may be made from very narrow flat material, typically of a thickness of 18 thousandths of an inch (1/2 mil) and having a diameter in the region of 130 mm. The blades may have entirely continuous knife-edge cutting surfaces around the whole of the circumference thereof or may have serrated, scalloped or saw tooth edges over at least a part of the circumference. It is envisaged, for example, that blades may be used having a certain arc of plain knife-edge interspersed with serrated or scalloped edge portions so that whichever type of cutting edge is most effective for the particular fruit in question will come into contact therewith at least over part of the blade circumference.

Plain knife-edge slitting or parting blades are preferred, however, as these exert the least peripheral force on the fruit during slicing.

In the preferred embodiment of the invention there are two arrays of blades laterally spaced from one another in an axial direction and a plurality of pairs of fruit holders on a continuous loop conveyor such that, in operation, successive pairs of fruit holders are carried under the blades in the same direction. In this way continuous slicing of fruit can be effected by loading the holders upstream of the blades and unloading them downstream. Such loading and unloading may be done manually or automatically as appropriate.

The drive for the rotary blades is preferably a pneumatic motor. This is a particularly tmE^rtEnt safety aspect since electric motors, requiring a supply of electricity to the apparatus, necessarily involve an additional risk in food preparation circumstances where, as mentioned above, fruit juice and other liquids may be present, which may tend to act as an electrolyte and may cause additional insulation problems. Likewise it is preferred that the conveyor is moved incrementally by a pneumatic linear actuator, the stroke of which is sufficiently great to move the or each fruit holder past the cutter blades in one movement. By using a pneumatic motor tor the drive to the blades and a pneumatic linear actuator for the conveyor it becomes necessary only to supply compressed air to the machine in order to obtain all the necessary functions.No electricity is required whatsoever.

Preferably the conveyor is formed as at least one endless loop of chain passing over two drums, one at each end of a supporting framework, for transmitting drive to the or each said fruit holders.

Two embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of a first embodiment; Figure 2 is a schematic perspective view illustrating the embodiment of Figure 1; Figure 3 is a pneumatic circuit diagram illustrating the control elements of the embodiment of Figure 1; and Figure 4 is a pneumatic circuit diagram illustrating the control elements of a second embodiment of the invention.

Referring now to the drawings, in Figure 1 the apparatus shown is formed as a free-standing unit mounted on wheels enabling it to be positioned easily at any point in the working environment. The apparatus comprises a supporting frame generally indicated 11 of rectangular form having upright legs 12 at each corner supported on castors or wheels 13 and spanned by longitudinal and tranverse rails comprising an upper longitudinal rail 14, an intermediate longitudinal rail 15 and a lower longitudinal rail 16, and corresponding upper, intermediate and lower transverse rails 17, 18, 19 respectively at each end of the apparatus. Intermediate support columns 20, 103 reinforce the horizontal longitudinal rails 14, 15, 16 at an intermediate point along their length.

The upper rails 14 and the transverse rail 17 between them define an upper working platform along which a plurality of fruit holders 27 are drawn by endless conveyor chains 25 which are joined together by the fruit holders 27 to form a conveyor generally indicated 24. The chains 25 of the conveyor 24 pass over drums 28, 29 one at each end of the loop, which are both freely rotatable.

The conveyor 24 is caused to advance by a pneumatic linear actuator 23 acting on the fruit holders 27 via a unidirectional linkage 26, such as a pawl and ratchet mechanism, which causes the fruit holders 27 to advance by one position as it is extended, and then retracts to engage the next adjacent holder 27 ready for the next cycle. The drum 29 is supported on side plates 22 fixed between the upper longitudinal rails 14 and the intermediate longitudinal rails 15, whilst the drum 28 at the other end is mounted on longitudinally extending horizontal supports 30 enabling adjustment of its position for tensioning purposes. Each of the fruit holders 27 is fixed at a single point along its lateral edge to the chain 25 at each side of the conveyor 24 to allow relative turning movement at the end of the conveyor loop as can be seen in the left hand end of Figures 1 and 2.

Situated at one end of the upper working surface 21 is a control panel 32 by means of which single strokes of the actuator 23 can be controlled to cause one pair of fruit holders 27 to pass through the cutters, or alternatively repeated reciprocation may be controlled for effectively continuous working as will be described in more detail below. Midway along the upper working surface is a slicing unit 31 which comprises a rectangular frame of upright walls 34 the purpose of which is to avoid any splashes of juice or other fluids escaping from the fruit whilst being sliced. In fact, the casing 33 has two upper covers which have been omitted from Figure 2 in order to show the interior parts exposed.

A shaft 35 is carried on bearings 36 between end walls 37, 38 of the casing 33, and is driven via a gearing arrangement 39 by a pneumatic motor 40. The shaft 35 carries two sets of circular slitting blades 104, 42 which are identical with one another. The slitting blades 104, 42 have a diameter in the region of 130 mm and are preferably made of stainless steel in the region of 18 thousandths of an inch thick (1/2 mil). Indeed, not only the blades 104, 42 but also all metal parts from which the apparatus of the invention is made are preferably formed from stainless steel in order to comply with safety and hygiene requirements. Non-metal components are preferably made of plastics material, particularly food-grade polypropylene or like hard plastics resistent to acids and boiling water and capable of being cleaned.

Between the blades 104, 42 and just under the shaft 35 is a comb 46 of longitudinally extending rods or bars, each of which is slightly smaller in diameter than the spacing between adjacent cutter discs 104, 42, the comb of rods or bars 46 being carried on transverse supports 80, 81 extending parallel to the axis of the shaft 35.

In operation of the machine illustrated, an appropriate source of compressed air is connected to the control panel 32 and, by acting on control switches 49 of the control panel 32 the compressed air is supplied to the pneumatic motor 40 driving the blades 104, 42 and to the pneumatic linear actuator 23. when, by acting on the control switches 49, the machine is set into operation, the pneumatic motor 40 drives the cutter discs 104, 42 to rotate in the direction illustrated by the rotary arrow of Figure 1 and, at the same time, the conveyor 10 is driven to displace the holders 27 in the direction of the arrow A of Figures 1 and 2.By placing fruit items in the recesses in the holders 27 these are then conveyed under the comb 46 which retains them in position as they come into contact with the slitting blades 104, 42 and, moreover, holds the slices in position after having been separated by contact with the blades 104, 42 whilst the holders 27 are carried beyond the blades out from the casing 33.

End covers 50, 51 at each end of the machine are provided for safety purposes. Under the end cover 50 there may be provided appropriate spray washing equipment for spraying a washing liquid over the holders 27 as they pass, and likewise a suitable collection tray may be positioned under the lower branch 58 of the conveyor to collect any juice falling from the cut fruit and/or any washing liquid from the washing apparatus under the cover 50.

Referring now to Figure 3, which shows the pneumatic circuit for control of the apparatus described hereinabove, by means of which the pneumatic linear actuator 23 and the pneumatic motor 40 can be selectively driven in order to operate the machine. The pneumatic circuit has an input 41 which is connected to a source of compressed air (not shown) and this input leaves via a first line 78 to a spring loaded piloted valve 43 the purpose of which will be explained below, and via a second line 44 through two safety valves 45, 46 to a line 47 leading to a safety stop switch 48 and then to the control input 49 of the valve 43 referred to above.The safety valves 45, 46 are connected to the two covers (not shown) over the cutter casing 33 in such a way that if either cover is removed the safety valve automatically moves to a position where the source is isolated and the pressure in the circuit is exhausted. If both covers are in position the safety valves 45, 46 adopt the position illustrated in Figure 3 and compressed air is supplied through the safety stop valve 48 to the piloting input 49 of the input-gate 79.

If, during operation of the machine an emergency occurs which requires immediate cessation of movement depression of the safety stop button 48 will commute it to a position where the incoming compressed air is cut off and the pressure in the circuit is evacuated. By cutting off the pressure passing through the stop valve 48 pressure at the control input 49 of the valve 43 is lost and this, likewise, commutes to a position where the incoming pressure is cut off and any residual pressure in the circuit is evacuated. From the input gate 79 an output line leads to the input 83 of a main control valve 82, whilst a first branch line 65 leads to one input of a NOT gate 63 and another branch line 66 leads to an input of a key control switch 67 operated by a key 68.

With the apparatus connected to a source of compressed air, but the key 68 removed, or turned to its "off" position, compressed air can reach the key control switch 67 and, through the input gate 79 can arrive at the input 83 of the main control valve 82 which, in these conditions, is maintained in the position illustrated in the drawings in which a first output 56 is connected through to an exhaust 55, whilst a second output 57 is connected to an input 60 of the linear actuator 23 which causes the actuator to retract and to a line 62 leading to the second input of the NOT gate 63.

The key switch 67 has an output line 69 leading to an indicator 70 which is sensitive to the pressure on the line 69 to provide an "on" indication when the key 68 is turned to allow compressed air to pass through the key control switch 67, and which automatically commutes to an "off" position if the key 68 is turned to exhaust the line 69. The line 69 is also connected to one input of a second NOT gate 71 which receives a second input on a line 72 connected to the first output 56 of the main control valve 82. The line 72 is also connected to the pneumatic motor 40 via a connector 73 and to the pneumatic linear actuator 23 via a connector 61.The arrival of fluid pressure at the output 56 thus causes the linear actuator 23 to extend and the motor 40 to run driving the cutters 104, 42 to rotate. The cutters 104, 42 are thus driven to rotate only whilst a fruit holder 27 is being passed beneath them by extension of the actuator 23. The output of the NOT gate 71 leads via a line 74 to the inputs of two energisation control valves 75, 76 each of which has a respective output leading to an input of an OR gate 77 the output of which leads to the pilot input 54 of the main control valve 82 opposite the pilot input 52 controlled by the output of the first NOT gate 63.

The control valves 75, 76 differ only in that the valve 75 has a mechanical actuating arrangement which holds it in its commuted position when switched whereas the valve 76 has a single push button which allows a pulse of pressure to pass through the valve only for as long as the push button is depressed, and then commutes to its off position when the push button is released.

Thus, in operation of the machine, when a source of compressed air is connected to the input 41 and the two guards controlling the valves 45, 46 are safely in place compressed air will pass along the line 44 through the two series-connected safety valves 45, 46 to the line 47 where, passing through the safety stop valve 48 it arrives at the pilot input 49 of the input gate 79 which is thus commuted to the position illustrated in Figure 3 where it allows compressed air arriving on the line 78 to pass through to the input 83 of the main control valve 82 which, being in the position illustrated in Figure 3, allows the compressed air to pass to the second outlet 57 and from there, via the connector 84 to cause the actuator 23 to retract and, providing a second input to the NOT gate 63 via the line 62 ensures that fluid pressure is applied via the line 64 to the pilot inlet 52 of the main control valve 82 holding it in the illustrated position. Compressed air also passes from the input gate 79 on the line 66 to the key control switch 67.

when the key 68 is turned the compressed air is allowed through the key control switch 67 to the indicator 70 which thus provides an indication that the machine is ready for service, and also via the NOT gate 71 the compressed air passes on the line 74 to the two inputs of the control valves 75, 76. If the valve 76 is pressed a pulse of cmpressed air passes through to the OR gate 77 and arrives at the pilot input 54 of the main control valve 82 causing this to commute, connecting the first outlet 56 to the input 83 and the second outlet 57 to the exhaust 53. The high pressure in the line 62 thus falls and the pressure at the connection 61 rises causing the linear actuator 23 to start to extend and the motor 40 to rotate.Any air in the actuator 23 on the side of the piston connected to the connector 84 can exhaust through the main control valve 82 and the exhaust 53.

when the actuator 23 has reached the end of its stroke the pressure in the line 62 has fallen to zero and the first NOT gate 63 therefore commutes applying pressure to the pilot inlet 52 of the main control valve 82 commuting this back to the position illustrated and allowing compressed air to escape through the exhaust 55 whilst incoming compressed air passes through the outlet 57 to the connector 84 causing a return stroke of the linear actuator 23. The motor 40 stops running. This continues until the piston reaches the end of its stroke where, the pressure at the connector 61 now being zero, the second NOT gate 71 commutes allowing the pressure fluid again to pass through the line 74 to the gate 76. This, however, is now closed and the circuit will therefore remain in this condition until further actuation of the valves 75 and 76.

If, instead of the valve 76, the valve 75 had been actuated, then the circuit would operate exactly as just described to cause first an extension of the actuator 23 followed, upon completion of this extension, by immediate retraction, with the difference that when retraction is complete and the NOT gate 71 commutes, because the valve 75 remains open it allows fluid under pressure to pass through the OR gate 77 to the pilot inlet 54 theeby causing the main valve 82 to commute again so that a new cycle of operations is commenced. This cycle continues repeating for as long as the valve .75 remains in its "on" position.

Turning now to Figure 4, in the alternative embodiment illustrated those components which are identical with or serve the same function as corresponding components in the embodiment of Figure 3 are identified with the same reference numerals. In particular, the conveyor cylinder 10 which advances the fruit holders 27 is supplied to advance via a connector 61 from a first output 56 of a main control valve 82 whilst retracting movement of this actuator is controlled via a connector 84 supplied with fluid under pressure from a second output 57 of the main control valve 82.

Although the circuit illustrated in Figure 4 has some components in common with that of Figure 3, the circuit configuration is different in the following respects. The fluid pressure outlet line 47 from the guard valves 45, 46 ( which are not shown in Figure 4 but are identical to those illustrated in Figure 3) passes to a safety stop switch 48 identical with the correspondingly referenced safety stop switch in the embodiment of Figure 3, but from here, instead of leading to the piloted inlet valve 43, the pressure lines leads directly to the on/off switch 67 which corresponds to the key control switch 67 of the embodiment of Figure 3. From the on/off switch 67 a line 69 leads to an indicator 70 exactly identical with that of the embodiment of Figure 3.However, instead of leading then to an input of the second NOT gate 71 the pressure line 69 leads to the pilot input 85 of a secondary control gate 86 the pressure input of which is fed directly from a pressure input line P and the output from which leads to the pneumatic motor 40 which controls the rotation of the cutter blades as in the embodiment of Figure 3.

Control pressure on the line 69 is also supplied, via a branch line 87 to the control input 88 of a third NOT gate 89 (the first and second NOT gates 63 and 71 having respective control inputs supplied with pressure from the first and second outputs 56, 57 respectively of the main control gate 59. The input of the third NOT gate 89 is supplied from the main pressure line P and the output is connected to a first pilot input 90 of a third control gate 91 which will be described in more detail below, and to one input 92 of an OR gate 93 a second input 94 of which is supplied from the output of the first NOT gate 63.

The third control gate 91 has a second pilot input 95 supplied from a single stroke control valve 96 which is spring-biased to a closed position and which can be moved by pressure of a control button 97 to an open position allowing communication from an input line 98, which communicates with the incoming control pressure line 87, to an output line 99 which leads to the second pilot input 95 of the third control gate 91. The third control gate 91 has a pressure input connected to the pressure line P and an output connected to the NOT gate 71 piloted by the pressure from the first output 56 of the primary control gate 59.

The primary control gate 59 is piloted by the output from an OR gate 77 corresponding to the OR gate 77 of the embodiment of Figure 3, which receives an input on one line 100 from the output of a 1repeat" control gate 75 and the other input on a line 101 from the output of a "single stroke" control gate 76 both of which are entirely similar to the correspondingly numbered components in the embodiment of Figure 3 with the exception that the input to the "repeat" control gate 75 is supplied on line 102 from the output of the NOT gate 71 as in the embodiment of Figure 3, whereas the input to the single stroke control gate 76 is supplied directly from the pressure line P.

Finally, the primary control gate 59 is connected directly to the pressure line P instead of the piloted inlet control gate 43 of the embodiment of Figure 3 and the first NOT gate 63 is likewise directly connected to the pressure line P.

The pneumatic circuit described above operates as follows.

First, assuming that the circuit is connected to a pressure source (not shown) all those components connected to the pressure line P will receive operating fluid pressure at the respective inputs, namely the input to the primary control gate 59, the input to the secondary control gate 86, the input to the third control gate 91, the input to the first NOT gate 63 and the input to the third NOT gate 89, and finally the input to the "single stroke" control gate 76.If, for the sake of the following description, it is assumed that the covers over the mechanism are open, the guard valves 45, 46 will be closed and therefore no pressure will arrive on the delivery line 47. when these guard valves are closed pressure is transmitted along the line 47 to the on/off switch 67 which, when it is in the "on" position, allows fluid pressure to pass into the line 69, energising the indicator 70 and delivering pressure to the piloting input 85 of the second control gate 86 to allow communication through this from the pressure line P to the pneumatic motor 40 so that this immediately starts to rotate.

Fluid pressure from the line 69 also flows into the branch line 87 and from there to the pilot input 88 of the NOT gate 89 thereby closing this gate, and also feeding on to the input 98 of the "stand by" control gate 96 Here the fluid pressure is interrupted so that operation of either the "single stroke" control gate 76 or the "repeat" control gate 75 will have no effect, and the circuit will remain in stand by mode until the push button 97 of the stand by control gate is depressed. Upon such depression fluid pressure passes from the input line 98 to the output line 99 and arrives at the second pilot input 95 of the third control gate 91 causing this to displace to a condition in which pressure can pass through the third control gate 91 from the pressure line P to the pressure input of the second NOT gate 71.To determine whether pressure is passed through the NOT gate 71 it is necessary to determine the condition of the primary control gate 59. Since the two main cycle control gates 75 and 76 are both assumed to be unoperated then no signal will be supplied from the OR gate 77 and the pilot input 54 of the primary control gate 59 will be at zero pressure. And the primary control gate 59 will thus be in the configuration illustrated in Figure 4 in which the pressure line P is connected through to the second output 57 from which fluid under pressure is supplied through the connector 84 into the linear actuator 23 to cause retraction of this, and also supplied to the control port of the NOT gate 63 thereby ensuring that this is closed and there is therefore no signal on the output line leading to the input 94 to the OR gate 93.In fact, it can be deduced that the last signal from either of the OR gates 77 or 93 will have been from the OR gate 93 since this will have received a signal on the output from the NOT gate 89 by exhaustionof the lines 69 and 87 when the covers were opened thereby closing the guard valves 45, 46 to reach the preliminary assumed configuration.

when the linear actuator 23 reaches the end of its stroke the pressure at the connector 61 will be zero, which pressure is also applied to the control port of the second NOT gate 71 thereby opening this and allowing fluid pressure to pass via the third control gate 91 to the input port of the "repeats control gate 75 (it will be recalled that the depression of the push button 97 applied fluid pressure to the control port 95 of the third control gate 91 thereby commuting this to a configuration in which the pressure inlet port is connected to the pressure outlet port).

If the "repeat" control gate 75 is then actuated it is moved to a position in which the pressure inlet port and pressure outlet port are put into communication and held in that configuration by mechanical means. Pressure is thus applied along line 100 to the OR gate 77 to provide control pressure to the pilot input 54 of the main control gate 59 causing this to commute to a configuration where the pressure inlet port is put into communication with the first pressure outlet port 56 thereby applying pressure to the chamber of the linear actuator 23 causing it to extend and at the same time applying pressure to the control port of the second NOT gate 71 closing off the pressure to the "repeat" gate 75. The primary control gate 59 remains in the commuted configuration, however, whilst the conveyor cylinder 23 continues to extend until the pressure at the connector 84 falls to zero thereby applying a zero pressure to the first NOT gate 63 and, via this, applying a control pressure to the input port 94 of the OR gate 93 the output from which is supplied to the pilot input 52 of the primary control gate 59 thereby causing this to commute back to the configuration illustrated in Figure 4 where the first connector 61 and the "extension" chamber of the linear actuator 23 are connected to the exhaust port 55 as illustrated, whilst the "retraction chambers of the linear actuator 23 is connected to the pressure line P via the connector 3.The actuator 23 thus retracts until it reaches the end of its stroke where the pressure at the connector 61 falls to zero, applying zero pressure to the control port of the second NOT gate 71 and thereby opening this gate to apply pressure through the third control gate 91 to the pressure inlet port of the "repeat" control gate 75 which feeds the OR gate 77 to cause commutation of the primary control gate 59 by application of pressure to the pilot input 54. The cycle thus repeats and continues repeating for as long as the pressure is applied and the "repeat" control gate 75 is held in the on position.

If it is desired to stop the operation of the machine this can be achieved either by switching off the "repeat" control gate 75, in which case the pressure applied via the second NOT gate 71 will not be transmitted through the OR gate 77 to commute the main control gate 59 and the actuator 23 will thus stop at the end of a retracting stroke, or if it is more urgent that the cycle should stop immediately, the emergency "stop" gate 48 may be actuated by depression of the emergency button thereby evacuating pressure from the lines 69 and 87, causing commutation of the third NOT gate 89 to apply pressure from the pressure line P both to the input 92 of the OR gate 93 thereby causing immediate commutation of the primary control gate 59 to the configuration illustrated in Figure 4 and at the same time applying pressure to the pilot input 90 of the third control gate 91 causing this to commute back to the position illustrated in Figure 4 where the pressure line P is blocked and the pressure output port from the third control gate 91 is connected to an exhaust. Again, therefore, the actuator 23 will stop when it reaches the retracting end of its stroke. If the safety guard valves 45 or 46 are commuted by opening a closure cover connected thereto the circuit will stop immediately since the pressure line P is connected downstream of these valves and is therefore immediately exhausted upon opening of the cover.

Subsequent closure of the cover will return the apparatus to the "stand by" condition described at the outset, requiring depression of the push button 97 before either of the "single stroke" or "repeat" control gates 76, 75 respectively will be effective by virtue of the fact that the third control gate 91 will remain in its commuted position as illustrated in Figure 4 until application of pressure to its pilot input 95.

Claims (16)

1. A fruit-slicing machine comprising a plurality of rotary blades spaced axially by a distance corresponding to the thickness of the slices of fruit to be formed thereby, at least one holder for fruit items, having a plurality of slots spaced by the same distance as the separation between the said rotary blades, and conveyor means for conveying the said fruit holder beneath the array of blades with the said slots in alignment with the blades whereby to slice a fruit item into a plurality of slices upon a single pass through the said rotary blades.

2. A fruit-slicing machine as claimed in Claim 1, in which the fruit holder has a recess in the upper surface thereof and the conveyor carries it past the array of blades in such a way that the blades enter the slots even at the lowermost part of the recess.

3. A fruit-slicing machine as claimed in Claim 1 or Claim 2, in which the conveyor is arranged to carry the fruit towards the edge of the blades moving downwardly.

4. A fruit-slicing machine as claimed in any preceding Claim, in which the blades have serrated edges.

5. A fruit-slicing machine as claimed in any of Claims 1 to 3, in which the blades are slitting blades having a continuous knife-edge around the whole of the circumference thereof.

6. A fruit-slicing machine as claimed in any preceding Claim, in which there are two arrays of blades and a plurality of pairs of fruit-holders on a continuous loop conveyor such that in operation successive pairs of fruit holders are carried under the blades in the same direction.

7. A fruit-slicing machine as claimed in any preceding Claim, in which the drive for the rotary blades and for the drive motor for the conveyor are both pneumatic motors.

8. A fruit-slicing machine as claimed in any preceding Claim, in which the conveyor is formed as an endless loop on a supporting framework between two drums, one at each end of the framework, over which pass endless chains for transmitting drive to the said conveyor carrying the said fruit holders.

9. A fruit-slicing machine as claimed in any preceding Claim, in which a control panel for the operation of the machine is positioned at one end of the said framework over the said conveyor.

10. A fruit-slicing machine as claimed in any preceding Claim, in which the cutter blades have associated guide rods or bars traversing spaces between them parallel to the path followed by the fruit, in the form of a comb acting to prevent fruit or fruit slices lifting from the fruit holder during cutting.

11. A fruit-slicing machine as claimed in any of Claims 8 to 10, in which the conveyor is driven by a linearly reciprocatable actuator connected thereto whereby to cause stepwise advance of the conveyor to displace each of a plurality of fruit holders past the cutting blades at each step.

12. A fruit-slicing machine as claimed in Claim 11 in which the cutter blades and the linearly reciprocatable actuator are energised such that the blades are driven only when the actuator is displacing in one direction; drive to the blades being removed when the actuator is displaced in the reverse direction.

13. A fruit-slicing machine as claimed in Claim 11 in which the cutter blades are driven to rotate continuously whilst power is supplied to the machine.

14. A fruit-slicing machine as claimed in any preceding Claim, in which the cutter blades and the linear actuator are energised by a pneumatic circuit which includes safety valves on all removable covers of the machine whereby to cut off supply of the pressure fluid when opened and to reinstate fluid pressure to the pneumatic circuit when the covers are closed.

15. A fruit-slicing machine as claimed in Claim 14, in which the safety valves associated with the removable covers are connected in a pneumatic circuit which acts to reinstate the circuit in a stand by condition upon closure of the valves, requiring operation of a further valve in order to continue operation of the machine.

16. A fruit-slicing machine substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.