WO1991006221A1

WO1991006221A1 - Ice-cream machine with rotating mixing member

Info

Publication number: WO1991006221A1
Application number: PCT/DK1990/000268
Authority: WO
Inventors: Torben Peter Petersen
Original assignee: Swen Nielsen Consult Aps
Priority date: 1989-10-26
Filing date: 1990-10-18
Publication date: 1991-05-16
Also published as: YU200790A; AU6547490A; JPH05505517A; CA2071884A1; DK533789D0; EP0497804A1

Abstract

In an ice-cream machine of the kind, in which a mixing cone (21) may be moved upwards and downwards from a position, in which it cooperates with a mixing auger, the new feature is that the means for moving the mixing cone upwards and downwards consist of an electric motor (2) lifting and lowering the mixing cone by means of a chain (4), one end of which is secured high up in the machine framework, its other end being secured to the carriage (20) carrying the mixing cone (21) and extending about a sprocket on the moveable part of the linear motor and another sprocket in the machine framework. In another embodiment (not shown), the sliding carriage is moved up and down by means of a screw shaft, the upper end of which is driven by the electric motor through suitable gearing. With this arrangement it is possible to replace the previously used pneumatic cylinder by electrically driven means without safety risks, as the motor (2) is placed at a safe distance from the mixing cone (21) and high up in the machine framework.

Description

ICE-CREAM MACHINE WITH ROTATING MIXING MEMBER

TECHNICAL FIELD

The present invention relates to an ice-cream machine of the kind set forth in the preamble of claim 1.

BACKGROUND ART

A number of ice-cream machines of the kind referred to initially are known, and as an example, the machine disclosed in US patent publication No. 4,755,060, may be referred to. In this known ice-cream machine, the means with which the mixing bowl can be moved in its own axial direction towards and away from the operating position or positions comprise a pneumatic cylinder, the movement of which is controlled by valves adapted for the purpose, said cylinder, of course, having to be supplied with energy in the form of compressed air from a compressor or a compressed-air plant.

The disadvantages associated with the use of a pneumatic cylinder may, of course, be remedied by replacing this cylinder with suitable electrical manoeuvering means, but in that case problems relat¬ ing to safety may arise, since ice-cream machines of the kind referred to here may in many cases be in¬ stalled in spaces, where the risk of electrical leakage to earth may be high, e.g. due to the moisture caused by the requisite cleaning of the spaces or rooms concerned. The cleaning of the machine itself may also comprise an element of risk, and apart from the purely safety-related aspect, the electrical equipment can easily be damaged, if it comes into contact with ice-cream mass of the kind being processed in these machines.

DISCLOSURE OF THE INVENTION

It is on this background the object of the present invention to provide an ice-cream machine of the kind referred to initially, in which the means for moving the mixing bowl are driven by electricity, without the measures necessary for this purpose causing a disproportionally high safety risk, and this object is achieved with an ice-cream machine, according to the present invention additionally exhibiting the features set forth in the characterising clause of claim 1. In this manner it is achieved that the electrically driven drive means is placed at a safe distance from the operating region of the mixing bowl and the mixing auger and at a level where the risk of entry of moisture is a minimum.

Advantageous embodiments of the ice-cream machine according to the present invention, the effects of which are explained in more detail in the following detailed portion of the present specification, are set forth in claims 2-6.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed specification, the present invention will be explained in more detail with reference to the drawings, in which

Figure 1 shows an embodiment of the ice-cream machine in side elevation and with the machine covers removed, Figure 2 shows the machine in front elevation and with the machine covers in place,

Figures 3-5 show the mixing auger and the mixing cone with the latter in three different height positions,

Figure 6 is a sectional view on a larger scale through the lowermost end of the mixing cone, the letter's bottom plate and the securing means for the bottom plate,

Figure 7 shows the bottom plate of the mixing cone, seen from above and in two different vertical sectional views.

Figure 8 shows the mixing auger on an enlarged scale, seen in elevation,

Figure 9 on the same scale as Figure 8 shows the knife belonging to the mixing auger and adapted for comminuting hard particles, seen in elevation, and

Figure 10 in a view similar to Figure 1 shows an embodiment of the machine, in which different means are used for raising and lowering the mixing done.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The exemplary embodiments of an ice-cream machine according to the present invention shown in the drawing comprise the following active working members: - a funnel-shaped mixing cone 21, the bottom of which, cf. especially Figures 6 and 7, is constituted by an upwardly plane bottom plate 21a, in which is formed an aperture 21b, through which the material having been processed can flow, a mixing auger 17, adapted to rotate when in operation, the external contour of which fits with the inside of the cone 21, and which at its lower end carries a knife 18 that may move axially but not rotationally relative to the auger 17, said knife 18 as shown in the example of Figure 9 comprising four radially protruding knife blades 18a adapted to cooperate with the aperture 21b in the bottom plate 21a, said knife 18 possibly also being spring loaded downwardly, a "cone elevator" or sliding carriage 20, which gliding on vertical columns 19 may be elevated to the operating positions shown in Figures 4 and 5, in which the inside of the cone 21 is close to or contacts the outside of the convolutions on the auger 17 respectively, and various operating means, control means, drive means and motor means, with which the movements of the auger 17 and the cone 21 may be carried out and controlled to achieve the desired operating functions.

The cone 21 may be permantly secured to the carriage 20, but is preferably removably positioned and guided in the carriage in such a manner, that the cone is held precisely coaxially with the auger 17. Likewise, the auger 17 may be permanently secured to its drive shaft 17a, but is preferably secured to the latter by means of a quick-acting coupling 16.

The auger 17 is preferably made of a not quite hard plastic material. In this manner, it is achieved in the operating position shown in Figure 5 that the auger wipes the material from the inside of the cone 21 and hence empties the latter in a more effective manner than has been possible with the previously used metal augers. A similar effect may be achieved by using a mixing cone 21 of plastic material, in which case the auger 17 may consist of metal, but in this case there is a greater risk that material will be abraded from the inside of the cone and hence contaminate the material being processed.

The sliding carriage 20 is secured to one end of a long chain 4, the other end of which as shown is anchored to the machine frame at a relatively high point. From the carriage 20, the chain 4 first passes over a sprocket 8 supported rotatably about a stationary axis in the machine frame, and from there below a sprocket 5 being rotatably supported on the movable part of an electrically driven linear motor, e.g. a so-called screw-and-nut motor 2, secured in the machine frame, finally ending in its anchorage point, as mentioned high up in the machine frame. When the linear motor 2 is actuated from the position shown in Figure 1, the sprocket 5 moves downward, causing the carriage 20 with the mixing cone 21 to be elevated with a speed twice as high. During the downward movement, the sprocket 5 or a member connected thereto passes and activates a number of switches 9-12 on a switch panel 13 secured to the machine frame. The switch 9, being placed uppermost, constitutes the uppermost end stop for the sprocket 5, i.e. the lowermost end stop for the carriage 20 with the mixing cone 21, whilst the switch 12 is the lowermost end stop for the sprocket 5 and hence the uppermost end stop for the mixing cone 21.

The intermediate switches 10 and 11 will during the downward movement of the sprocket 5, i.e. the upward movement of the mixing cone 21, firstly cause the auger 17, for this purpose being driven by a main motor 1, to be started, and the upward movement of the mixing cone to be stopped temporarily so as to make it possible for the auger 17 to mix the material having been introduced into the mixing cone, cf. Figure 4, before the mixing cone is moved to the final dispensing position shown in Figure 5.

In the example shown, the movable part of the linear motor 2 is guided by a guide rail 30 secured in the machine frame.

Both the main motor 1 and the various switches 9-12 referred to are preferably connected to a control box

3 containing the requisite connections, relays including any semiconductor means - and fuses, the control box 3 also being adapted to receive control signals from an operating panel 22 situated uppermost on the front side of the machine facing towards the right in Figure 1, said panel 22 inter alia comprising a main switch 23, a starting switch 24, an error alarm lamp 25, an emergency stop 26, and a stop 27. The control box 3 is also adapted to deliver information or alarm signals, e.g. to said error alarm lamp 25 and/or an alarm bell (not shown) or the like.

Apart from the means and functions described, relating to the normal operation of the ice-cream machine, the control box 3 is also adapted to receive signals from a rinsing switch 29 placed lowermost and to the right in Figure 2, and in dependence thereof to execute a rinsing operation comprising that the mixing cone 21 in its highest position, in which it, cf. Figure 5, is in intimate contact with the auger 17, or possibly in the somewhat lower position shown in Figure 4 is closed upwardly by a closure plate 15, after which a rinsing-water stream through a pair of rinsing tubes 14 is directed through the mixing cone, preferably whilst the auger 17 is rotating. If so desired, the rinsing operation may be followed by hot air or steam being blown through the parts in question in order to remove rinsing-water residue and/or to sterilize the active surfaces on the auger 17 and the mixing cone 21.

A quick-acting coupling 6 is adapted to connect the ice-cream machine with a rinsing-liquid source, e.g. the local waterworks - provided, of course, that the public-health regulations are adhered to. A V-belt 7 transmits the driving power from the main motor 1 to the auger 17. The safety shield 28 shown in Figure 2 protects the operating personnel against involuntary contact with the auger 17 and the knife 18, and is in a manner known, but not shown, mechanically connected to a safety switch adapted to interrupt the operation of the machine, when the shield 28 is removed.

As is evident from Figures 6, 7 and 9, the aperture 21b in the bottom plate 21a is shaped like "a star¬ fish with six arms", each arm of which extends all the way out to the transition from the inside of the cone 21 to the upper side of the bottom plate 21a, whilst the knife 18 consists of four radially directed knife blades 18a, the radial length of which generally correspond to the radial extent of each arm in the aperture 21b.

Because each arm in the aperture 21b and each knife blade 18a on the knife 18 extends substantially all the way out to the inside of the mixing cup 21 in the latter's lowermost part, hard particles, such as lumps of frozen fruit, nuts and the like, will be subjected to a shearing action as soon as they hit the bottom plate 21a, in contrast to the situation in previously known machines of this kind, in which the apertures in the bottom plate had a limited radial extent, so that "dead annular zones" were created, in which the knife blades theoretically seen could go on pushing the hard particles around and around on the bottom plate, without the particles coming into engagement with the aperture or apertures in the latter. When considering that the stirring effect caused by the auger 17 and the knife 18 with its knife blades 18a on the mass of ice (not shown) placed in the mixing cup, unavoidably causes heating of the mass of ice, it will be obvious that the period of residence in the mixing cup 21 should be as short as possible. With the special shape of the aperture 21b as provided by the present invention, the "dead annular zones" are avoided, as each and every hard particle hitting the upper side of the bottom plate 21a will immmediately be caught by the next knife blade 18a and carried along to that arm of the aperture 21b nearest in the direction of rotation, in which arm the first shearing of the particle occurs, the particle during the ensuing passage across the remaining arms in the aperture 21b gradually being completely comminuted and accompanying the remainder of the mass of ice downwards through the aperture, forming a profiled extrudate, cf. Figure 5.

As evident from Figures 7 and 9, the knife 18 has a smaller number, viz. four, knife blades 18a than the number, viz. six, of arms in the aperture 21b in the bottom plate 21a. In this manner, it is avoided that all the knife blades 18a at the same time cooperate with a corresponding number of arms in the aperture 21b, which in the worst possible case - hard particles in engagement in front of all knife blades - could lead to a very high load on the knife 18 and at least to strong vibrations, if the number of hard particles in the mass of ice is relatively large. A similar effect would, of course, be achieved by having a greater number of knife blades than arms in the aperture, but with the arrangement shown, better strength relationships are achieved. By having both the number of knife blades 18a and the number of arms in the aperture 21b as even numbers it is achieved that the force of reaction on the knife 18 becomes more symmetrical than would be the case with an odd number of knife blades and aperture arms respectively.

As evident from the sectional view to the right in Figure 7, the side surfaces 21c and 21d in the arms in the aperture 21b may extend at an oblique angle downwardly and away from each other. If the auger 17 and hence the knife 18 with the knife blades 18a in a "normal" manner rotates "with the sun", i.e. clockwise when viewed from above, the knife edges 18b on the knife blades 18a will when the latter rotate cooperate with the uppermost edges of the side surfaces 21c in a similar manner as in a pair of scissors. Here, it has proved advantageous to let at least the side surfaces 21c extend at an oblique angle as shown, as this improves the shearing effect and reduces the production of heat. When the opposite side surfaces 21d also extend obliquely in a similar manner, this is in part due to the production process, in which two oppositely situated arms are shaped simultaneously, such as by a milling process, in part that experience has shown that this divergence of the side surfaces, especially in cooperation with a corresponding divergence of the end surfaces 21e in the arms, and the downwardly convex shape of the lower side 21f of the bottom plate 21a, provide highly advantageous outflow conditions for that "snake" of ice mass being extruded through the aperture 21b.

The bottom plate 21a is preferably releasably secured to the lower side of the mixing cone 21, e.g. as shown in Figure 6 by means of a union nut 21g.

It is not shown in the drawing how the knife 18 is connected to the auger 17 in such a manner, that the knife may move axially, possibly under a spring load, relative to the auger, but not turn relative to the latter. It does however, lie within the normal scope of work for a skilled mechanic to devise a mutual construction and arrangement of the two members, suitable for this purpose. A known possibility has already been indicated in the US patent publication No. 4,755,060 referred to initially.

In the embodiment shown in Figure 10, the chain 4, sprockets 5 and 8, and the linear motor 2 of Figure 1 have been replaced by a screw shaft 31 threaded into the sliding carriage 20 and being driven by a gear motor 33 through a toothed belt 32. The use of a screw shaft instead of a chain has the advantage of giving positive driving force both in the upward and downward directions, so that increased friction between the carriage 20 and the columns 19, caused e.g. by the latter having had ice mass spilled on them, will normally not prevent the carriage 20 from being lowered. An overload switch (not shown) connected to the gear motor 33 could be used, if necessary, to prevent jamming and to give an alarm signal, informing the operator that the columns need cleaning.

In order as far as possible to avoid such spilling on the columns 19, a telescoping apron 34 is placed in front of the columns 19 and the screw shaft 31, always shielding these components from the space between the auger 17 and the mixing cone 21, where spilling is most likely to take place.

Figure 10 also shows a number of switches 9a-12a, adapted to be acted upon by an actuating roller 35 on the sliding carriage 20. These switches 9a-12a play the same role as the switches 9-2 shown in Figure 1, for which reason further explanation should not be required.

As will be apparent, Figure 10 shows the machine with the mixing cone 21 in an intermediate position, i.e. a position between the lowermost filling position shown in Figure 10 and the uppermost operating positions shown in Figures 4 and 5. Components not mentioned in the present description of Figure 10, but having the same reference numbers as components shown in Figure 1, have the same functions as the latter.

Claims

CLAIMS :

1. Ice-cream machine for processing and dispensing ice-cream and of the kind comprising a) a substantially funnel-shaped mixing bowl (21), the bottom of which is constituted by a bottom plate (21a) with at least one aperture (21b) extending therethrough, b) a sliding carriage (20) adapted to carry the bowl (21) and itself being vertically glidingly supported on vertical columns (19) rigidly secured to the machine framework, c) rotatably supported in the machine framework a mixing auger (17), the outer contour of which corresponds to the internal surface of the bowl (21), d) means (2, 4, 5,8; 31-33), with which the bowl (21) may be moved in its own axial direction towards and away from an operating position, in which the outer contour of the auger (17) lies at a short distance from or contacts the internal surface of the bowl (21), and e) means (1, 7, 16) to rotate the auger (17) rela¬ tive to the bowl (21) at least in said operating position or positions, c h a r a c t e r i z e d in f) that the means (2, 4, 5, 8; 31-33), with which the bowl (21) can be moved in its own axial direction, comprise mechanical moving means (4, 5, 8; 31) adapted to be driven by an electric motor (2; 33), said electric motor being placed in the uppermost part of the machine framework and on the side of said columns (19) facing away from said auger (17) and bowl (21).

2. Ice-cream machine according to claim 1, c h a r a c t e r i z e d in that the means (2, 4, 5, 8), with which the bowl (21) can be moved in its own axial direction, comprise a) a flexible tension-transmitting member, such as a chain (4), one end of which is secured to said sliding carriage (20), and b) an electrically driven linear motor (2) functionally connected to said chain (4) in such a manner, that said motor be means of said chain can move said carriage (20) to an extent corresponding to the desired extent of the movement of the bowl (21).

3. Ice-cream machine according to claim 2, c h a r a c t e r i z e d in a) that the other end of said chain (4) is secured to a relatively highly placed point in the machine framework, from which it extends downwardly and makes a turn about a sprocket (5) rotatably sup¬ ported on the moveable part of the linear motor (2) to extent outwardly towards a sprocket (8) rotatably supported in the machine framework, and from there in a downward direction towards a carriage (20), and b) that a series of switches (9-12) are placed in the machine framework, said switches being placed along the path of movement for the moveable path of the linear motor (2) and adapted to the be acted upon by this part in its various height positions, said switches (9-12) being adapted to control the various functions of the machine, the uppermost (9) and lowermost (12) switch preferably being adapted to act as end stops for the linear motor (2).

4. Ice-cream machine according to claim 1, c h a r a c t e r i z e d in that the means (31-33), with which the bowl (21) can be moved in its own axial direction, comprise a) a screw shaft (31) extending between and parallel to said columns (19) and rotatably supported in the machine framework and adapted to cooperate with said sliding carriage (20), and b) an electric motor (33) adapted to drive (32) said screw shaft (31) through the latter's uppermost end, whereas c) a series of switches (9a-12a) are placed in the machine framework, said switches being placed in the path of movement of the sliding carriage (20) or a part (35) secured thereto and adapted to be acted upon by the latter in- its various height positions, said switches (9a-12a) being adapted to control the various functions of the machine, the lowermost (9a) and the uppermost (12a) switch preferably being adapted to act as end stops for the movements of the sliding carriage (20).

5. Ice-cream machine according to claim 3 or 4, c h a r a c t e r i z e d by a control box (3) being at least adapted to receive control signals from said switches (9-12, 9a-12a) and from one of a number of manually operable control means (23, 24, 26, 27) placed in a control panel (22), to control the rotating means (1, 7, 16) for the auger (17) as well as the electric motor (2, 33) and possibly to transmit information signals to one or a number of signalling means (25) situated in the control panel (22) or elsewhere.

6. Ice-cream machine according to any one or any of the claims 1-5, characterized by a set of rinsing means consisting of a) at least one rinsing tube (14) being placed in such a manner, that it debouches in the uppermost part of the bowl (21), when the latter is in its highest position, and b) a closure plate (15) adapted to close the bowl upwardly, when the bowl is in its highest position, whereas c) the arrangement is such, that when a control means (28) designated for this purpose is acted upon manually, cl) the bowl (21) is moved to its said highest position, c2) the closure plate (15) is brought into abutment with the upper edge of the bowl (21), closing the latter upwardly, c3) the auger (17) is made to rotate, and c4) rinsing liquid, e.g. water, is made to flow from the rinsing tube or tubes (14) down into the bowl (21).