US 3875423 A
An electrically driven kneading and mixing machine with different speed ranges, having a guard grille which, when raised, switches off the machine. The machine is equipped with two push button switches and two electrically driven time switches. The switches are interconnected in such a way that one of the timing switches is used for programming the machine operation, whereas the other time switch, on expiration of the timing of the first time switch, actuates an increased speed range.
Description (OCR text may contain errors)
D United States Patent 3,875,423
Kemper Apr. 1, 1975  Emma AND MIXING MACHINE FOREIGN PATENTS OR APPLICATIONS 1 lnvemori e 'i wybqelslrasse 1.|7s,s03 10/1964 Germany 30m l2 Zunch-Zolhkon, Switzerland 22 Fil M 13 1973 Primary ExaminerHerman Hohauser Attorney, Agent, or Firm-Spencer & Kaye [2l] App]. No.: 340,843
 ABSTRACT  Foreign Application Priority Data An electrically driven kneading and mixing machine Mar. 15 I972 Germany 22l2430 ith d ff rent speed rang s. ha ing a guard grille which, when raised, switches off the machine. The ma-  US. Cl..... 307/113, 259/DlG. l9, 259/DlG. 35 chine is equipped with two push button switches and  Int. Cl. H0111 47/00 two l ri y riven ime wi h The s itches re  Field of Search 307/! I2, 92, I13, 115, n r nnected in uch a way hat one of the timing 307/l41.8, l4l.4, 141; 259/DlG. l9, DIG. 35 switches is used for programming the machine operation, whereas the other time switch, on expiration of  References Cited the timing of the first time switch, actuates an in- UNITED STATES PATENTS "eased Speed range- 2,857,533 l0/l958 Miller 259/DIG. l9 8 Claims, 3 Drawing Figures KNEADING AND MIXING MACHINE The invention relates to an electrically driven kneading and mixing machine with different speed ranges, which is provided with a guard grille which on being lifted up switches off the machine in any speed range as well as with a time switch and a pressure switch.
Such a machine is known for example from the German Accepted Pat. Document No: l,l78,803. It is required of this bakery machine that by swinging up the guard grille the drive motor is disconnected and that after lowering the grille the machine again starts with the lowest speed. The machine is provided with two speed stages, in order to obtain the greatest possible torque. If the machine known from the abovementioned Accepted Pat. Document is stopped by opening the guard grille at its smallest speed, it is sufficient for restarting it to close the guard grille.
If the machine, however, is switched off at its highest speed by opening the grille, the grille must be closed for the restarting and in addition a cam operated pole reversing switch must be rotated about a switch position. In this case it is disadvantageous that the position of the cam pole reversing switch first has to be determined and before starting the machine a switching operation has to be effected.
SUMMARY OF THE INVENTION The invention seeks to avoid or reduce these disadvantages.
Further, the invention seeks to make the entire operating cycle pre-programmable in such a manner that the operating procedures, starting at different speeds, can be switched on and off automatically.
To solve this problem it is already known to use mechanically wound timing units. The latter, however, have the decisive disadvantage that the clockwork mechanism. when an operating process is interrupted, for example. by raising the guard grille. carries on running so that the interrupted program cannot be easily continued. Since, in this case, the already expired time of the program carried out is not indicated, because namely the clockwork mechanisms carry on running, there exists the danger that a charge, interrupted in this manner, cannot be finished according to the intended specification. A further disadvantage of this known device consists in that such an automatic unit cannot be lay-passed, at least not during operation, so that, for example in the case of disturbance of one of the clockwork mechanisms, the whole machine breaks down.
The invention also seeks to eliminate or reduce these disadvantages.
According to the invention, in the case of an electrically driven kneading and mixing machine with different speed ranges, which is provided with a guard grille switching off the machine in each speed range when it is raised, as well as with a time switch and a push button switch, a further electrically driven time switch and a further push button switch are located in series with respect to the first time switch and the first pressure switch, the first time switch being constructed in such a manner that on expiration of its programmed operational time, an increased speed range can be switched in, which is controllable by the second time switch.
The second time switch is preferably made programmable in the whole operating time.
In a further development of the invention, there result for a particular problem, two solutions in the case of which the time switches in each case have a program setting indicator and in each case a program expiration indicator. According to the first solution, the program expiration indicators, on actuation of the guard grille, are arrested at the time point of the interruption of operations and controls the rest of the pre-programmed operating time on continuation of the operating program. In accordance with the second solution of this indicated problem, the program expiration indicators, on actuation of the guard grille, fall back into the program set position so that, on restarting the machine by actuation of the first or second pressure switch, the originally programmed program restarts.
The following further features according to the invention are suitable for both forms of embodiment.
Thus, in a further development of the invention, a toggle switch is in parallel with both time switches so that the automatic unit can be switched off even during operation, the machine operating further without interruption with the speed switched on by the push button switch.
The program set by the time switches can be varied manually in an advantageous manner during operation by actuating the time switches or push button switches.
Telltale lamps are coupled, in an advantageous manner, to the pressure switches, in each case associated with a certain operating speed, so that the operating state prevailing in each case is visually indicated. Such a device indicating the operational state is advantageous, particularly in the case of processing machines of the type present here, since, for example, the set speed of the kneading tool in the operational state cannot be easily recognized directly, since the tool is almost completely immersed in the dough to be processed.
A reversing switch is proposed to control the bowls direction of rotation and the bowls speed. A toggle or inching switch is provided for the short-duration rotation of the bowl with its smallest speed. The actuation elements are arranged on the front side of the machine part constructed as a tool carrier which can be raised.
The invention should preferably fulfil the following requirements:
I. The machine must be capable of being turned off by several elements, such as guard grille and time switch;
2. The machine can start at any set speed after a stoppage by actuating one single pressure switch;
3. The machine should, after it was stopped by opening the guard grille, not carry on running, if the guard grille is closed;
4. Only a single switch should be actuated after adjusting a predetermined program;
5. A manual reconnection of the switching elements should not be necessary;
6. The possibility of interrupting and/or changing the program during the operational course should be given;
7. The automatic switching unit should be capable of being by-passed at all times, i.e., even during operation;
8. The set program should be capable of either automatically starting from the beginning or should be continued from the interruption point, in the case of interruption of the operational process and restarting of the machine;
9. The direction of rotation and speed of the bowl should be adjustable independently of the set program and finally there should exist the possibility, likewise independently of the set program, of rotating the bowl for a short time at its smallest speed.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a side view of an electrically driven kneading and mixing machine,
FIG. 2 shows a circuit diagram for the operation and FIG. 3 shows the circuit diagram of the control in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT According to FIG. I, a rotatable bowl I is secured on a movable gear unit on machine housing 2. Kneading tools 3, which are guided in the turret 4 of the gear unit or machine housing 2, project into the bowl I. A guard grille 5 is tiltably mounted about the pivot 6 and mechanically connected to a switch b4 (FIG. 3) inside the housing. To raise the kneading tool 3 out of the bowl I, the turret 5 can be raised. The actuating elements are on the front side 7 of the turret 4, so that the switches to be actuated are arranged clearly and easily accessible.
The circuit diagrams shown in FIGS. 2 and 3 are provided with symbols according to DIN 40 700 and DIN 40 709 to DIN 40 719 so that these may be understood by a person skilled in the art without the need for a full explanation.
The circuit diagram l shown on the left-hand side of FIG. 2 shows the circuit for the drive motor lml of the bowl, which has generally conventional safety fuses lcl, a reversing switch L I and corresponding contactors lcl and lcZ.
On the right-hand side of FIG. 2 is shown the circuit II for the drive motor 2ml of the kneading tools, from which it is obvious that the motor M can be operated at two different speeds. Polechangeable asynchronous motors, which are operated with three phase current, are appropriately used for the drive. The pole changing of the motors in a forwards and backwards rotation or from one speed stage into another is effected with the help of contactors. The bowl motor Iml has two contactors. namely contactors with the coils lcl and lc2. The kneading spiral motor 2m1 has three contactors, namely contactors with the coils 2cl, 2c2 and 2c3. The coil of the contactor 1c2 has five contacts, whereas all the other contactors each have three contacts on the motor side.
FIG. 3 shows the connection, with regard to circuitry, of the individual actuating elements for actuating the motor control coils, which coils are arranged just above terminal board L. The circuit in this case is located between the phase T and Mp and has a safety fuse e5 in series circuit, as well as thermal cutouts 2e4, leS and le4. This center tap Mp of a delta circuit of a threephase current is connected to the lower terminal board Ll,4 to L2,2 so that all the points 4 to 13 are electrically connected to each other. Beneath the terminal board there is given, using for reference, the terminal points 4 to 14 in each case, information as to the operation of the associated contacts (normally open or make" auxiliary contact S and normally closed or break" auxiliary contact 0). Thus, for example, the data under the terminal point 4 thus means that on energisation of the coil lcl no normally open auxiliary contact is actuated, whereas the normally closed auxiliary contact above the terminal point 9 is opened, which contact is also given the reference numerals lcl and the contact points 11 and I2. The data regarding the terminal point 6 thus means that on energisation of the coils 2cl the normally open auxiliary contact above the terminal point 7 which is also given the reference numeral 2cl, and has the contacts 3i and 32, is closed, whereas the normally closed auxiliary contact above the terminal point point 10 which also carries the reference numeral point 2cl and has the terminal point I] and 12, is opened and so on. The coil d3 belongs to the second time switch and has an electro-magnetic ope rating system with a magnetic starting delay. The normally closed auxiliary contact of the time switch, which has the contact points 5 and 6, is given the reference numeral d1 on the left-hand side of FIG. 3. This normally closed auxiliary contact contact dl is mechanically connected to the normally closed auxiliary contact d1 which has the switching contacts I and 2, the latter being shown in the upper part of FIG. 3, the normally closed auxiliary contacts, in turn, being mechanically coupled to the actual switch mechanism of the time switch. Further another contact, constructed as 21 normally open auxiliary contact or as a closing contact, with the contact point 7,8 as well as a coil, belong to this time switch, which is arranged circuit wise above the contact point 13 on the terminal board L. b3 denotes a push-button switch effectively acting as an inching switch which serves to cause the bowl to rotate for a short time at its lowest speed during the switch actuation, independently of the set program. The push button or inching switch b3 has contacts 3 and 4 and has a hand operation with the symbol for the direction of action. The switch contact b3 is mechanically connected to the opening contact and to the normally closed auxiliary contact with the contacts II and 12; b0 with the contact points I and 2 represent the hand operated main switch with hand operation, which is like wise constructed as a normally closed auxiliary contact and has a device for automatic reset when the actuation force stops. The main switch b0 lies parallel to the toggle switch b3. Connected in series with the main switch are the first time switch (II, and in parallel, the second time switch with its contacts d3. In parallel with the contact d1, which is mechanically actuated by the time switch, is a toggle switch with the make auxiliary contact b5 and the contact points 3] and 32, which is not coupled with any further normally closed auxiliary contact or normally open auxiliary contacts. The break contact b4 which is mechanically connected to the guard grille and has the contact contacts 3 and 4, is in series with the time switch contacts d1. In series therewith follows the push button switch bl in the form of a make contact with the contacts 3 and 4, which has a device for automatic reset in the direction of the arrow when the actuating force is removed. In series with this push button switch is the normally open auxiliary contact b6 which again is constructed as a toggle switch as in the case of b5 and is parallel to the break contact with the contacts 1,2 which in turn is mechanically connected to the contact d3 and the contact points 3,4. The switch b2, constructed as a push button switch with hand actuation, has a break contact with the contacts 1 and 2, which is mechanically coupled to a make contact 3,4.
Furthermore, regarding the make auxiliary contacts b5 and b6 these are a toggle switching arrangement, which assume two different circuit positions, which is indicated by the v in front of the circuit symbol. The auxiliary contactor d2 is energised on actuation of the main contactor 2cl, since the contactor Zcl also actuates contact 2cl above d2.
The first push-button switch bl serves to turn on a slow speed of the kneading tool, whereas the second push-button switch b2 serves to switch on the higher speed of the kneading tool. The motor given the reference M in FIG. 3 serves to drive the time switching unit.
The telltale lamp hl, serves for the visual indication of the switching state of the first push button switch bl, whereas the control lamp h2 visually shows the switching state of the second push button switch b2.
As is obvious from the circuit diagram according to FIG. 3. without any further ado, a first time switch d1, after the expiration of its period, triggers the second time switch d3, which now takes over the control process alone. Since both time switches are driven by one motor, synchronism of the time switches is ensured in accordance with the invention. After expiration of the total operating time programmed into the switch d3, the latter switch (d3) automatically switches off this machine.
At all times manual intervention is possible, independently of the automatic effects caused by the time switches dl and d3, by actuating the switches bl and b2, so that the kneading tool can be driven at all times independently of the automatic units with an operational speed which is associated with the pressure switches bl or b2. Moreover, in accordance with the invention, the automatic unit can also be shortcircuited at all times by actuation of the toggle switch b5, b6, so that the automatic unit is switched off thereby. Two purposes are achieved by these measures, namely, on the one hand, it is ensured that in the case of failure of one or two time switches, the machine can be operated further by manual actuation of the corresponding pressure switches and, on the other hand, there exists the possibility of making the machine operate for a period of time which is not programmable by the time switches.
Thus a fully-automatic kneading time/control is achieved with the present invention, both the mixing time and the pure kneading time being freely selectable independently of each other, namely by corresponding programming of the time switches, an automatic switchover taking place from one operating process to the next one, so that thereby the whole process is automated in a simple manner. As FIG. 3 shows further, the circuit is constructed predominantly by contactors, which represent the best, safest and most durable of switchgear, which are actuated merely by control equipment, i.e., control switches, which in turn only have to switch the current for the magnetic coils. Thus, all the switching elements are designed for a robust reliable operation, a further advantage being seen in that the circuit, in spite of the great diversity of its possibilities, is extraordinarily simply constructed.
What I claim is:
1. An electrically driven kneading and mixing machine operating in different speed ranges, having a lift able guard grille; means connected to the grille for switching off the machine in any speed range when the grille is lifted; a first push-button switch; means connected to said first push-button switch for driving the machine at a relatively low speed upon actuation of the first push-button switch; a first timer connected to the first push-button switch for determining the operating period of the machine at the relatively low speed; comprising in combination:
a. a second push-button switch connected in series with said first push-button switch and said first timer;
b. means connected to said second push-button switch for driving the machine at a relatively high speed upon actuation of said second push-button switch;
c. a second timer connected to said second pushbutton switch for determining the operating period of the machine at the relatively high speed, said second timer being connected in series with said first push-button switch and said first timer, said second timer being programmable with the entire work period;
d. means connected to said first timer for switching, upon expiration of the work period of said first timer, to the relatively high speed by the actuation of said second push-button switch;
e. a first toggle switch connected parallel with said first timer and in series with said first and second push-button switches; and
f. a second toggle switch connected parallel with said second timer and in series with said first and second push-button switches.
2. Machine according to claim 1, wherein the timers each have a program setting indicator and in a program expiration indicator and wherein on actuating the guard grille, the program expiration indicator is arrested at the point in time of the operation interruption and, with the continuance of the operating program, controls the remaining part of the pre-programmed operating time.
3. Machine according to claim 1, wherein the timers each have a program setting indicator and in a program expiration indicator and wherein on actuating the guard grille, the program expiration indicators fall back into the setting position, so that the originally programmed program restarts when the machine is switched on again by actuation of the first or second push button switch.
4. Machine according to claim 1, wherein the program set by the timers can be varied manually during operation, by actuation of the timers or the push button switches.
5. Machine according to claim 1, wherein indicating lamps are coupled with the push button switches, so that the operational state prevalent in each case is indicated visually.
6. Machine according to claim 1, wherein a reversing switch is provided to control the bowl rotation sense and bowl speed.
7. Machine according to claim 1, wherein a toggle or inching switch is provided for rotating the bowl for a short time at its lowest speed.
8. Machine according to claim 1, wherein the actuating elements are arranged on the front side of the turret of the machine part which can be raised and is constructed as a tool carrier.