DE1149503B - Device for actuating the ladle of centrifugal casting machines - Google Patents

Description

The invention relates to a device for actuating the by a hydraulic pressure cylinder tiltable ladle of centrifugal casting machines, the capacity of which is the successive Allows casting multiple tubes. The invention is based on the object of actuation to make the ladle so that with a single charge of the ladle with molten Metal, d. H. Several pipes are poured in succession until they are completely emptied can.

It is known that the tilting speed of a ladle of this type, from which the amount of in the rotating mold introduced metal depends, is regulated so that within narrow tolerances Pipes or other elements of uniform wall thickness and the like within narrow tolerances given weight.

From this it follows that on the one hand the beginning and the end of the tilting and pouring of the metal in the mold must be released with great precision and on the other hand, a fabrication in large series to be poured into the mold from the beginning to the end of each pour The amount of metal must be constant and precisely reproducible.

It has already been proposed to satisfy the first condition that the ladle before and after each of the successive casts a forward impulse is given through which the Pouring is initiated immediately, which is caused by a backward impulse or a "falling back" of the pan follows, in order to interrupt the pouring immediately, as well as to provide appropriate means, by which, depending on the time, the tilting movement of the ladle at the end of the movement initiated by the impulse and the simultaneous start of pouring, d. H. of the beginning of pouring is regulated on. These funds make it possible to achieve the desired results achieve if the conditions of a completely constant initial filling of the ladle and the also constant distance of the level of the molten metal in the ladle from theirs Ground are always fulfilled at the end of each pulse.

In order to also meet the second condition, i. H. keeping it constant from the beginning to the end of the casting To meet the amount of metal poured out, it would of course be desirable that the capacity and In particular, the cross section of the ladle is completely constant from one casting process to the other is because only then can that be achieved at

Device for operating the ladle of centrifugal casting machines

Applicant:

Compagnie de Pont-a-Mousson,

Societe anonyme,
Nancy, Meurthe-et-Moselle (France)

Representative: Dipl.-Ing. R. H. Bahr

and Dipl.-Ph.ys. E. Betzier, patent attorneys,

Herne, Freiligrathstr. 19th

Claimed priority:
France of March 25, 1960 (No. 822 516 Seine)

The same amount of molten metal is poured out at the same tilting speed.

However, this condition can be due to the more or less uneven wear of the refractory lining of the ladle as well as the heels of slag on the lining practical impossible to be fulfilled. These also have irregularities in the surface of the liner also means that the level difference of the melt in the ladle from its bottom at the end each impulse is slightly different.

The invention relates to a device for actuating tiltable ladles of the above basically described type that after each filling of the pan the implementation of a Cycle allows a certain number of successive casts. The new actuator automatically provides a constant delivery in a constant amount of the poured into the centrifugal mold molten metal with exact repeatability from one casting to the next, regardless of irregularities in the inner surface

so the ladle, sure.

The new actuator is characterized by an electric pump for the pressure medium to

309 598/249

Tilting or pouring and a further electric pump connected in parallel to turn on the Ladle, which are supplied with power by two independent feed circuits, furthermore several rheostats in the circuit of the tilt pump, one of which was attached to the socket pin Disc are switched on one after the other, finally a photoelectric cell, which responds to the appearance of the molten metal on the dump edge of the ladle and which in turn controls devices, which at this point in time, the pitch pump is ineffective set.

This combination makes it possible on the one hand that at the beginning of each individual casting process, the two electric pumps work in parallel on the tilting cylinder, so that, because of the large amount of hydraulic fluid supplied, the tilting process proceeds more quickly to its loading. 6 is a view corresponding to FIG. 4 of the pouring ladle in an intermediate tilting position according to a modified embodiment.

The embodiment shown in Figs. 1 to 4 shows the application of the invention to a ladle 1, approximately in the shape of a cylinder sector, of large capacity, which contains the amount of molten cast iron or other liquid metal m required for the successive pouring of a certain number of pipes, e.g. B. of six pipes, is required, these six casts form a "casting circuit".

This ladle has a cylindrical wall 2 (Fig. 1 and 2) with the axis XX, two lateral circular, plane-parallel sectors 3 and a flat wall 4, which forms a pouring spout S in the upper part between the two circular sectors 3.

The ladle carries on the outside on its sides

number of pipes involves checking the results obtained in each cast pipe Section of the tipping process of the ladle were achieved and each weight error of the pipe

of the remedy, the setting of this rheostat according to the result of the casting of a Rohres in the first cycle guarantees this

Beginning results, but this as soon as the pan 20 walls 3 in the vicinity of the pouring spout 5 a contained molten metal has reached the pouring edge of the pair of pivot pins 6, which lie in the axis XX pan, because then the peeling and in from the parallel posts 7, which the supporting photocell comes into effect. On the other hand, the scaffolding of the ladle form, supported bearings it is possible from this point on to rotate in the course of a. At the end of one of the pins 6 is wedged on this first casting circuit, the casting of a multiple 25 a circular disc 8 (Fig. 1, 2 and 4), which has two notches 9.9 a on its circumference, whose task continues will be explained below.

Under the pouring spout 5 of the pouring ladle is up or down by an individual control 30 a spout 10, which protrudes into a on a the channel 11 mounted on this section associated with the regulating resistor frame opens. About this

Channel 11, the mold 13 of the centrifugal casting machine rotating about an approximately horizontal axis YY is supplied with liquid cast iron. The shape offers that the casting in the same casting section in 35 13 j _st rotatably inside the movable part M runs properly in all subsequent circuits. Of course, the new device and 13 forms a jacket 14 around the mold and, via rollers 15, its pouring ladle for pouring a number of pipes on a rolling track 16 parallel to the channel 11, which are equal to or smaller than the number of runs. Together with the mold, the jacket can execute a control resistance, ie a back-and-forth movement that is suitable for tilting sections. In the first case, a single resistor controls the casting of all pipes of the same rank, for example by means of a hydraulic pressure cylinder
within each casting cycle, in the second case
becomes the pipe of a given rank within
each casting circuit by adjusting several 45
Resistances affected.

The invention also relates to a system for centrifugal casting of pipes and similar elements with rotating mold and ladle, which with the new, basically described above Device is equipped.

The details and further features of the invention will become apparent from the following description of exemplary embodiments thereof with reference to the drawings:

Fig. 1 schematically illustrates the overall arrangement of an actuator for the ladle according to the invention before casting;

Figure 2 is a view of the ladle in direction
of the arrow F of Fig. 1, partially away- 60 forms approximately a tangent to the cylinder surface 2,

17 with piston 18 via a piston rod 19, which is connected to the overall arrangement 14 by a boom 20 connected, is effected.

The pouring ladle 1 is pivoted by the hydraulic-electric actuating device with hydraulic cylinder V, which has been perfected according to the invention.

In the lower region of the cylinder surface 2 of the pouring ladle 1, a fork bracket 21 is attached to it which is the end of the piston rod 22 of the piston

23 of the single-acting hydraulic cylinder V is articulated. The lower end of the cylinder body

24 of the hydraulic cylinder is pivoted about an axis 25 on a fork body 25 a, which is attached to the floor in such a position that the printing cylinder is slightly opposite the vertical in a direction that is when the ladle is in the fill position prior to pouring,

Broken;

Figure 3 is a schematic diagram of the electrical circuitry for the ladle actuator;

Figure 4 is an enlarged plan view of a detail of the ladle in the lower position;

5 graphically illustrates the change in the pivoting angle of the pouring ladle as a function from the time;

is inclined.

In the lower part of the body of the hydraulic cylinder 24 opens a line 26. This line is connected to a first slide selector S ₁ , the slide 27 can assume three positions and z. B. is operated by hand depending on the longitudinal movements of the movable part M of the centrifugal casting machine. With this voter are

5 6

On the one hand, a line 28 for the supply of cylinder V. Accordingly, the piston 23 lifts this pressure oil, which _{is fed by an electric pump F 1} , which is used as an on-pressure cylinder, the ladle 1, through a line, liquid iron into the pouring spout 5 appears. This 29 is sucked out of a container B , and the starting phase is on.

on the other hand, an emptying line 30, which in this 5 In the schematic representation of FIG. 5, in

Container opens, connected. which the pivot angle χ of the casting

By a two-wire electric mainstream pan as ordinates and the time t as abscissa aufkreis 47 (Fig. 1) which are supported on a direct current source U, the Anstellphase is is by the Segangeschlossen, is a two-wire circuit 48 ment a _x b _x illustrated .

for the supply of the electromagnet E ₁ when the melt appears in the casting branch. This circuit 48 is closed by a contactor C ₁ beak 5, the thereby excited photoelectrical cell 49 closes the contactor C ₁ , so that the electromagnet corresponding closing is excited by one of magnet E ₁ and the slide 32 of the the in front of the pouring spout 5 of the pouring ladle 1 an- Hahnes J to the right into the _{photoelectric cell 49, which is shut down in the pump P 2 and} brings the infra to the set position against the action of a spring 36 from the molten cast iron. The liquid red rays conveyed by this pump responds as soon as the molten iron speed is passed from now on to the discharge line 39 to the pouring spout 5 at the level of the outlet, and the pump P ₁ works only on the Leipunktes is visible, given impulse takes place. To tion 26. The pouring ladle 1 continues to tip, but for this purpose the photoelectric cell 49 is slower at 20. As a result, after the pulse has been given in series at y and ζ to a, which has the effect that the melt micro-relay 50, which flows into the overflow 10 in an electrical weak circuit via the pouring spout 5, is connected . This microrelay closes the melt through this overflow and the channel, a contactor C ₁₁ in a circuit with 11 in the mold 13 with a predetermined, of the greater amperage, through which a relay 51 with 25 supply of the pump P ₁ supplied speed current will, in turn, on the contactor C ₁ speed. The movable part M of the centrifugal casting acts. machine moves to its extreme left position, so-

The electromagnet E ₂ receives current through a soon the melt is at the right end of the casting two-wire circuit 52, which is located from the main current channel 11, and starts from this eye circle 47 is branched off and through the part C _{2 of} a 30 look at move back right. This is double contactor C ₂ -C ₃ , which is controlled, for example, by hand, which is shown in FIG. 5 by segment O ₁ C _1. "Light phase. The difference between the ordinates

The mode of operation of the single points b ₁ and C ₁ according to the invention corresponds to the tilting around

direction is as follows: the angle x, (Fig. 4), d. H. the first casting process.

It is assumed that the liquid 35 during the translational movement of the

Iron-filled ladle is in the rest position of part M of the centrifugal casting machine to the right

(Fig. 1) is located. First of all, the simplest case is the melt over the entire length of the mold 13

considered in which the number of poured to be poured. A short time before the end of the path

Pipes equal to that of the rheostats ^ ₁ ... R ₆ (Fig. 3), the machine to the right becomes the slide 27

ie tilting sections of the ladle according to the 40 and 27 a of the selectors S ₁ and S ₂ by hand up to the

The example chosen is six such sections. moved to the right end position and thereby the cylinder

In the idle state, the slide 27 of the V are switched to relief. The ladle 1 selector S ₁ and 27 a of the selector 5th, in the middle, then tilts back quickly, so that the level of the in the standstill position of the ladle, which is shown in Fig. 1 her melt down below the casting, corresponding Position and which lowers with 45 beak 5 and the pouring stops, and two shafts 33 and 35 and a collar 34 - although until the sliders 27 and 27a of the voters ^ equipped slider 32 of the tap / in the left, and S ₂ in the middle , shutdown position back to the operation of the pump P ₂ corresponding position. have been moved. This is the tilting back phase illustrated in FIG. 5 by the slide 41 of valve K is in segment C ₁ d _x. The right position in which he closes the line 40. 50 with the casting of a pipe is finished.
The moving part of the centrifugal casting machine M is during the demolding of the pipe, ie it is in the extreme right position. When the machine is at a standstill, the pouring ladle is

The printing cylinder 17 is stopped for the purpose of the process if. This standstill phase is due to the centrifugal casting machine to the left in the direction of the horizontal segment ά _± α. ₂ of FIG. It is to be pointed out to the pouring channel 11 in a known manner with 55 that when the level of the pressure medium is applied. At this point in time, melt in the ladle begins to tilt back, as soon as the machine is started, the movement below the pouring spout 5 drops, the slide 27 and 27 a of the selector S ₁ and the selector photcelectric cell 49 is no longer excited. The lers 5th, moved by hand to the left, and contactor C ₁ opens, and the slide 32 of the valve by closing the main switch 62, the electrons J will automatically pump under the action of the spring P ₁ , P., started, namely the electrical 36 moves in the left direction into the operating position of the circuit 61 of the pitch pump P ₂ and the power pitch pump P _2.

circuit 53 of the electric _{pump P 1} for pouring. Nevertheless, the pump P _{2 is} still ineffective because it is automatically closed, the latter because in the idle state the slide 27 a of the selector * "^ the pressure oil is closed, the contactor C _{3 is} closed, on the other hand the Zwil - 65 blocks before it enters the line 31a lingsschütz C _2. The pumps P ₁ and P ₂ can, by first connecting the delivery line 37 of the then simultaneously and parallel pressure fluid pump P ₂ with the relief line 30a through the lines 26 and 31 in the pressure and then the line 37 closes.

As soon as the centrifugal casting machine is put back into operation, the cycle for casting the second tube begins again, corresponding to a ₂ b. ₂ c ₂ d ₂ a ₃ (Fig. 5) and further. It should be noted that the ordinate corresponds to point b, a somewhat larger ordinate than point C ₁ , which represents the end of pouring in the previous pour, namely because the segment O ₂ Z) ₂ illustrates

Actuators of the switches I ₁ and J ₁ from the notches 9 and 9 a free, while the switches / ₂ and / ₂ fall into these notches. The same work process now takes place again up to the end of the sixth casting section X ₆ .

When the ladle 1 is empty at the end of the tilting movement, the contactor C _{2 is} closed by hand, whereby the backward movement of the casting

by the difference between the ordinates of b _± and C _{1 is} greater than the pivoting angle of the pouring ladle in the _{opposite direction to that of the arrow Z 1} for the purpose of interrupting the pouring process.

At the end of the last tilting section x _{G of} the ladle 1, ie after its backward movement phase, the slider 27 and 27 a of the selector S ₁ and S ₂ in the middle standstill position

light impulse has the clear purpose, the pan 1 and the opening of the contactor C ₃ causes the level of the melt compared to that at the end of the io. As a result, all rheostats and the tilting or pouring located at C _{1 are} very quickly switched off for the pouring electric pump P _1. As soon as the pouring ladle 1 is allowed to rise in order to cause the melt to overflow into its starting position for the new one via the spout 5 and thus the filling has come back, the contactor C _{2 will be} triggered by the pouring process. This pulse acts again opened by hand, whereby the contactor C ₃ in a pivoting of the pouring ladle 15 is brought to its normal closed position and denizuin the direction of the arrow f _L (Fig. 4) by an angle that follows the electric pump P ₁ again to Is brought to run.

In the embodiment described above, in which six tubes are cast with a filling 20 of the ladle, if one of the cast tubes, e.g. B. the third, has a weight slightly outside the allowable tolerances, while the previous tube was good - which is a local irregularity in the shape of the casting, the contactor C _{2 is} manually placed in the previous, X ₃ , of the six completions. The slide 41 of the valve K is then shown sections - the lamp L ₃ is moved to the left by its opening by the electromagnet E ₂ and illuminates that of the rheostat, namely R ₃ , so that the hydraulic cylinder 24 is acted on via the lines must be set to the speeds 40 and 42 on discharge. As a result, the tilting movement of the pouring ladle in that time lowers its piston completely and correcting the pouring ladle 30 point at which the local irregularity in the initial position for the first third section X ₃ affects the accuracy of the poured amount. For the casting of the following pipe (fourth section X ₄ ) takes, because the rheostat R _{3 was} short-circuited,

has reached (Fig. 1), the contactor C _{2 is} opened. 35 the tipping speed of the ladle automatically

Under these prerequisites, the precision returns to the value it had before the correction.

In contrast, the changed setting of the rheostat R ₃ once and for all with each new cycle of casting six pipes for

At the beginning of the pouring of the first pipe of a 40 the third pipe of all subsequent circuits the geGruppe of such the switch C _{1 is} secured by hand, exact weight and this despite the upper actuated and thereby the feed circuit 55 of the surface error of the pouring ladle, which is in the third Ablais V ₁ closed. The relay _{causes the switching section X 3 of} the casting cycle to occur, Z _{1 is} opened and the rheostat R _{1 is} activated.

switches. Since the other switch L ₂ ... i _{6 is} open 45 ie the one in which the number of during one

Casting moved back. This backward movement phase is illustrated in FIG. 5 by the segment d _e e _6. As soon as the ladle returns to its original position

sion control of the swivel speed of the ladle during pouring in the following, from Fig. 3 and 4 evident way:

perfect tilting movement of the ladle no longer _{corresponds to the number of sections X 1} ... X ₈ (Fig. 4), but less

are, the relays r ₂ ... r _e remain unexcited and the rheostats R ₂ ... R ₆ short-circuited via their shunts 54 and therefore out of operation.

At the same time, the only switch Z _{1 will} be examined as this is. In this case, it is determined that its movable member 58 speaks in FIG. 50. Each section only falls to a fraction of the Ge-Rast9a and only switches on _{the lamp L 1.} This lamp indicates the rheostat R ₁ in this way, the rheostat assigned to the section itself only has an influence on this fraction of this weight by means of the assigned handwheel 60. So z. B., (Fig. 1) must be acted on the control panel 59, if only three pipes per casting cycle are to be cast in such a way from the following cycle of six casts 55, each rheostat only to half the weight of the pouring speed in the first casting act on each of the pipes. In the first casting cycle, two lamps L light up one after the other during the casting of the same pipe and indicate the two rheostats that must be acted on in the given case in order to set the weight of the pipe of the same priority for the following casting cycles.

In summary, it can be seen how because of the arrangement of the photoelectric cell 49 before

the path x, ie during the pouring of the pouring spout 5 the appearance of the melt in the tail for pouring the first pipe continues. Pouring spout gives the impulse for the start of the AusWhen the second pouring section x ₂ for the pouring pouring phase. This ensures that the second pipe has come close, the effective start of the casting come exactly at the beginning of the

each cycle and thus also the amount of melt, to change something, if the poured in the first cycle corresponding pipe is a little too heavy or a little too light.

The lamp L ₁ remains switched on and the rheostat R ₁ in operation as long as the actuators of the switches ^ and Z ₁ engage in the notches 9 and 9 a , which occurs during the pivoting of the ladle

Pouring phase in the course of the tilting movement of the ladle is equivalent to.

Thanks to the fractional adjustment of the tipping speed of the ladle also results a constant release of the melt and consequently the certainty that the shape is always the the same amount of melt is fed and tubes of regular thickness and exact weight are obtained will.

In the modified embodiment shown in Fig. 6, the detent 9 a of the first example (Fig. 4) is offset by a detent 9 b, opposite to arrow J ₁ relative to the detent 9 a by half the central angle of a section X to the rear is replaced.

Therefore, the lights L _x ... L ₆ do not light up at the same time as the rheostats R ₁ ... R _{6 are put into operation} , but rather with a delay. This modified embodiment is of interest in the event that the level of the melt at the end of each individual casting does not exactly match one of the theoretical boundaries between the successive sections X ₁ ... x _ti (as shown in dashed lines in FIG ), but on the contrary corresponds to a level shown in dash-dotted lines at XZ ₁ , which lies between two successive theoretical limits. The tilting movement Z ₁ ZZ ₂ corresponds to the volume required for casting a pipe. This occurs when the ladle has such a surface irregularity that, for the same capacity, the level of the melt is higher or lower than the normal level, or finally, if a molten residue of any volume is used, the ladle is not exactly up to the theoretical level fills. The latter case is assumed in the figure. The pouring ladle is therefore at the beginning in the inclined position in which the level of the melt reaches the vicinity of the pouring spout 5. A pulse phase is then sufficient to cause the melt to overflow over the pouring spout and thus initiate the casting.

The signaling takes place in the following way: At the beginning of the casting of the first tube, which takes place on the end of the second section x ₂ , the actuating member of the switch / ₂ falls into the detent 9b . As a result, the lamp L ₂ lights up, which indicates that the second half of the second section has been exceeded and consequently the second section adds very little to the weight of the pipe. The third casting section X ₃ is approaching very quickly. This causes the switch / ₃ to close, the rheostat R _{3 to be switched on} and the rheostat R _{2 to be switched off.} When the first half of the melt of the third section x _{s is} poured out, the actuator of the switch / ₂ comes free from the detent 9 b of the cam 8, while that of the switch J ₃ falls into the detent and the lamp L ₃ lights up.

When the fourth section X ₄ approaches, the rheostat follows i? ₄ the rheostat R ₃ . The lamp L ₃ remains bright until the first half of the amount of melt corresponding to the fourth section has been poured out. At this point in time, the latch 9b causes the lamp L ₄ to light up, while the lamp L ₃ goes out. The lamp L ₄ remains switched on until the end of the casting of the first tube, as this extends to the second half of the fourth section x ₄ , which corresponds to a rotated position of the disk 8, in which the latch 9b is opposite the switch / _4.

The lighting up of the lamps L _{1 and L 4} after the start of casting shows that the third and fourth sections X 3 and X _{4 provide} most of the weight of the first tube and that R _s and R _A act on the rheostasis to change the pouring speed if the first tube is too heavy or too light. The delayed switching on of the lamps in the event of a hook in each section χ compared to switching on the associated rheostats therefore has the advantage that it is possible to distinguish the sections during which more than half of the melt has been poured out from those during which less than half of the melt is poured out, and consequently to regulate the weight of the pipe with greater precision by only taking into account the sections during which more than half of the pipe weight was poured out in the control process.

Of course, the invention is not limited to those described in detail above and in the Examples shown in the drawings, which are only to be regarded as such, are limited.

For example, the above can be applied to a centrifugal casting machine with translationally moved Form of the De Lavaud type described invention also applies to a centrifugal casting machine with solid Arens-type form can be applied.

Furthermore, the pouring ladle can be subdivided into any number of sections concentric to the tilting axis XX , the number of which corresponds to that of the pipes to be poured successively with a single filling of the ladle, and according to the desired precision of the control of the pouring speed depending on the weight tolerances of the pipes .

Furthermore, the slides 27, 27 a of the selectors S ₁ and S ₂ for controlling the movements of the ladle can also be operated automatically as a function of the movements of the centrifugal casting machine M by means known as such.

Finally, the delayed switching on of the signal lamps by others known as such can also be used Means, e.g. B. be done by timing relays.

Claims (10)

Patent claims: 1. Device for actuating the pouring ladle, which can be tilted by a hydraulic pressure cylinder, of centrifugal casting machines, the capacity of which allows the successive pouring of several pipes, characterized by an electric pump (P ₁ ) for the pressure medium for tilting or pouring and a further electric pump (P ₂ ) for adjusting the ladle, which are supplied with power by two independent feed circuits (53, 61), and several rheostats (R ₁ ... R ₆ ) in the circuit of the tilting pump (P ₁ ), which are operated by one on the ladle pin attached disc (8) are switched on one after the other, finally a photoelectric cell (49), which responds to the appearance of the molten metal on the tipping edge of the ladle (1) and which in turn 309 598/249 directions (J) controls which at this point in time put the pitch pump (P ₂ ) out of action. 2. Device according to claim 1, characterized by a first selector (S ₂₎ a valve (J) in the pressure medium line of the Anstellpumpe (P _2), interrupts and by pulse of the photoelectric cell (49) the pressure medium flow of the pump (P ₂₎ , also a second selector (S ₁ ) in the pressure medium line of the pump (P ₁ ), the slides (27, 27 ″) of the two selectors (S ₁ , S ₂ ) being connected to one another and movable between two positions, in one of which the two electric _{pumps (P 1} , P ₂ ) at the same time, namely the pump for the adjustment (P ₂ ) with the tap (J) and the pump (P ₁ ) for the pressure cylinder (V) , while they are in the other slide position are switched to relief. 3. Apparatus according to claim 1 or 2, characterized in that the control rheostats (R ₁ ... R ₆ ) are connected in series with a contactor (C ₃ ) lying in the feed circuit of the tilt pump (P ₁ ) and for each the rheostat a short-circuit switch (Z ₁ .. J ₆ ) controlled by the disk (8) is arranged. 4. Apparatus according to claim 3, characterized by electromagnetic relays between each switch (Z ₁ ... Z ₆ ) and the disc (8). 5. Apparatus according to claim 4, characterized in that the coil circuit of the relay is connected to a general supply circuit (48) in which a switch (Z ₁ ... Z ₆ ) is located, on which the disc (8) acts. 6. Apparatus according to claim 5, characterized in that each rheostat (A ₁ ... R ₆ ) is assigned _{a signal lamp (L 1} ... L ₆ ) connected to the general supply circuit (48). 7. Apparatus according to claim 6, characterized in that the control switches (Z ₁ ... Z ₆ ) of the rheostats (R ₁ ... R ₆ ) and (Z ₁ ... / ₆ ) of the lamps (L ₁ .. . L ₆ ) are arranged around the cam (8) so that each of the lamps (L ₁ ... L ₆ ) with a certain delay compared to the time when the associated rheostat (R ₁ ... R _e ) is switched on receives. 8. The device according to claim 2, characterized by a relief valve (K) in the pressure medium line (26) for completely emptying the pressure cylinder (V). 9. Apparatus according to claim 8, characterized in that the relief valve (K) is an electric valve controlled by a contactor (C _2). 10. Apparatus according to claim 3 and 9, characterized in that the contactor (C ₂ ) is connected to the switch (C ₃ ) in the feed circuit of the electric pump (P ₁ ) for tilting in such a way that each of the two switches when the other is open, is closed. Considered publications: U.S. Patent No. 2489479;
"Excerpts from German patent applications", Vol. 19, 1948, p. 652, file number V 41596 VI a. 1 sheet of drawings © 309 598/249 5.63