US3362020A

US3362020A - Transfluxor circuit

Info

Publication number: US3362020A
Application number: US329346A
Authority: US
Inventors: Hans Reiner
Original assignee: International Standard Electric Corp
Current assignee: International Standard Electric Corp
Priority date: 1958-06-03
Filing date: 1963-12-05
Publication date: 1968-01-02
Anticipated expiration: 1985-01-02
Also published as: BE584382A; DE1075153B; GB891405A; FR1228579A

Description

Jan. 2, 1968 v H. REINER 3,362,020

TRANSFLUXOR CIRCUIT Original Filed May 29, 1959 3 Sh ets-She t, 1

INVENTOR.

H.REINER myw 3 Sheets-Sheet 2 Original Filed May 29, 1959 INVENTOR.

H. REINER Jan. 2, 1968 H. REINER TRANSF'LUXOR CIRCUIT 3 Sheets-Sheet 5 Original Filed May 29, 1959 INVENTOR.

BY H. REINER ArfwP/vEy United States Patent Ofi ice 3,362,020 Patented Jan. 2, 1968 ABSTRACT OF THE DISCLOSURE In a memory device for the setting of a transfluxor, a

single apertured magnetic core with a rectangular hysteresis loop is provided as a driver core and is connected in such a way that resaturation pulses are capable of being applied to one input winding of the driver core and in that one output winding of this driver core together with one control winding of the transfluxor are connected in a circuit closed in at least one direction of current flux so that a constant voltage versus time integral will be set to the control winding at least during the one resat-uration of the driver core.

Cross reference to related applications This application is a continuation of application Ser. No. 816,788, filed May 29, 1959, and now abandoned, for a Transfiuxor Circuit.

The present invention relates to a transfluxor circuit, particularly suitable for the setting-up of storage circuits, logical networks and the like. The employment of the transfluxor with such types of circuits is already known. It bears the advantage that the informations as stored in the transfluxor are capable of being read without being destroyed. However, the employment of the transfluxor also is entailed by a number of difiiculties which are due to the mode of operation of the transfluxor.

The transfluxor in its most simple form consists, as is shown in FIGURE 1, of a ferrite core 1 having two

borings

2 and 3, by which the yokes I, II, III are constituted. Usually the dimensions are chosen such that the cross-section of the yoke I is equal to the sum of the cross-sections of the yokes II and III. The yoke I carries at least one control winding S via which the transfluxor can be set or blocked respectively. However, there may also be provided separate control windings for Setting and Blocking. T-he yoke IH carries a call-up winding e and a readout winding a. Only in the set, but not in the blocked condition will the transfiuxor supply an output signal. In this case the reading can be effected with the aid of an alternating voltage or by the application of individual pulses of alternating polarity.

The mode of operation of the transfluxor is based on the reciprocal action of the two magnetic circuits surrounding the two

borings

2 and 3. When in the blocked condition the core material in all three of the yokes is at the same point of remanence, by which a resaturation of the circuit around the boring 3 with the yokes II and III is rendered impossible. For effecting the setting of the transfluxor the circuit around the boring 2 is partly resaturated. In the set condition the core material in the yoke I is partly in the one, and partly in the other point of remanence, whereas in the yokes II and HI there exist opposite remanence conditions.

Accordingly, the transfluxor is a flux-sensitive circuit element.

It is obvious that the setting of the transfluxor places high demands on the dosage of the current, which is to be fed to the control winding. This is particularly the case when in the practical applications also the temperature influence has still to be considered, because the temperature dependence of the coercive force has an efiect upon the setting accuracy.

There also exists the possibility of eliecting the flux variation, which is necessary for the setting purpose, by the application of a predetermined voltage versus time integral, as is customary e.g. in the case of the step-by-step setting of counting reactors. Also in this case the temperature has an unfavorable influence.

The present invention is based on the problem of providing an almost temperature-insensitive transfiuxor circuit not requiring a special dimensioning of the currents or pulses respectively, which are necessary for the operation, this transfiuxor circuit especially being suitable for the construction of storages, counting cores and shift registers.

According to the invention this problem is solved in that for the setting of the transfluxor a single-apertured magnetic core with a rectangular hysteresis loop is provided as a driver core and is connected in such a way that resaturation pulses are capable of being applied to one input winding of the driver core, and in that one output winding of this driver core, together with one control winding of the transfluxor are connected in a circuit closed in at least one direction of current flux, so that a constant voltage versus time integral will be fed to the control winding at least during the one resaturation of the driver core. With respect to the temperature compensation it is of advantage to use driver and transfiuxor cores of the same kind of material. In order to effect the setting of the transfluxor by means of only one resaturation of the driver core the dimensions of the core should appropriately be chosen such that the product of cross-section and number of turns is half as big for the driver core as for the transfiuxor. If the setting is supposed to be eliected only after 11 resaturations of the driver core then, however, the circuit arrangement is to be dimensioned in such a way that the products of the cross-section and the number of windings with respect to the transfluxor and the driver core have a relationship such as 1:211.

The circuit arrangements according to the invention are particularly suitable for the construction of shifting registers. Such shift registers, of course, may also be operated as counting devices or connecting-through devices (linkaccess switching devices) for transmission paths, hence for example, as channel switches.

In general, a shifting register which is constructed with the aid of trausfluxor circuits according to the invention, is laid out in such a way that there is provided one singleapertured driver core and one transfluxor for each register stage, and in that an output winding applied to the transfluxor of the one stage is connected with an input winding of the single-apertured driver core of the next successive stages.

In the following various exemplified embodiments and further details of the invention will be described in particular with reference to FIGURES 1 to 7 of the accompanying drawings, in which:

FIGURE 1 shows a transtluxor comprising two borings;

FIGURE 2 shows a circuit arrangement according to the invention in which the single-apertured driver core is set by pulses;

FIGURE 3 shows a circuit arrangement in which the single-apertured driver core is set by direct-current;

FIGURE 4 shows a shifting register comprising transfiuxor circuits according to FIGURE 2;

FIGURE 5 shows a shifting register comprising transfiuxor circuits according to FIGURE 3, in which together with the withdrawal of the useful signal the setting of the single-apertured driver core is effected;

FIGURE 6 shows a shifting register comprising delay circuits or delay line elements and only one stepping line for cases Where the driver core is set by pulses; and

FIGURE 7 shows a shifting register comprising delay line elements and only one stepping line for cases where the driver core is set by direct-current.

According to the present invention the transfluxor is set by a signal having a predetermined voltage versus time integral characteristic. The voltage versus time integral signal is taken from a single-apertured driver core upon the resaturation thereof by a pulse of high energy. To this end an extracting or readout winding of the driver core is connected with a corresponding control winding of the transfluxor. In the course of this, however, care will have to be taken that a backsaturation of the driver core remains without a reaction upon the setting of the transfiuxor. For this reason, as is shown in FIGURE 2, the circuit arrangement can be made in such a way that the resaturation pulses are only capable of being transferred in the one direction from the driver core to the transfluxor, in that the output winding W2 of the driver core is connected via a diode G with the control winding 1 of the transfluxor.

Structure and mode of operation of such an arrangement will be described in the following with reference to FIGURE 2. This circuit arrangement comprises a single-apertured driver core K1 and a transfluxor K2. The driver core K1 is provided with the input windings W1 and W3, as well as with anoutput winding W2, while the transfiuxor K2 is provided with two control windings S1 and S2, and with an output winding 02, all three of which enclose or surround the yoke I. In addition thereto the transfiuxor K2, over the yoke III, carries a call-up winding e and a readout winding a. As already mentioned hereinbefore, the windings W2 and S1 are connected via the diode G with a circuit which is completed or closed in the one direction.

For determining a defined starting point, it is assumed, that at the beginning, strong restoring pulses have been applied to the windings W3 and S2, so that the driver core K1 and the transfiuxer K2 are in the state of a negative remanence, i.e. that the transfluxor is in the unoperated state. Now when applying a resaturation pulse via the winding W1 to the driver core K1, by which the core is completely resaturated and thus transferred to the state of the positive remanence, an output pulse will appear at the winding W2, having a predetermined voltage versus time integral characteristic. This output pulse is transferred via the diode G to the control winding S1 of the transfluxor, for effecting the setting thereof. By the pulse applied to the control winding S1, the transfiuxor is partly resaturated. Since the resaturation progresses from the inside towards the outside, the yoke II is in the state of a positive remanence subsequently to the setting, while the yoke III remains in the state of negative remanence, if, according to the invention, the cross-sectional dimensions of K1 and K2 have been chosen correspondingly or in a suitable way. It has already been mentioned hereinbefore, that these dimensions can be chosen such that only several resaturations of the core K1 will effect the proper setting of the transfluxor, hence just the complete resaturation in the yorke II, to the state of positive remanence. During the setting of the transfluxor via the control winding $1 an output signal of somewhat uncertain voltage versus time integral characteristic may be derived via the additional output winding a2. An output signal with an opposite polarity will be obtained at the output winding a2 whenever the transfluxor, subsequently to the setting by a restoring pulse, is blocked or rendered unoperated by the control Winding $2. This additional output winding a2, however, may also be omitted whenever the aforementioned output signals are not required in the arrangement for any other purposes.

When the transfluxor is in the set condition, then the core material, surrounding the boring 3, can be resaturated. For example, when applying to the input winding e of the transfluxor an alternating voltage, then the output winding a will deliver a relatively big output signal. However, if the transfluxor is in the unoperated state, then in both the yokes II and III the same direction of flux exists, and the resaturation of the material within the surrounding of the boring 3 is rendered impossible.

The application of an alternating voltage to the input winding e will then cause no output signal to appear at the output winding a.

If, subsequently to the blocking of the transfluxor, the transfluxor is to be reset via its control winding S2, then prior thereto the driver core K1 has to be resaturated again to the state of negative remanence, for instance, by the application of a restoring pulse via the winding W3. Upon back saturation of K1 a signal will likewise appear at the output winding W2 corresponding to the change in flux. However, this signal has an opposite polarity and, therefore, cannot be transferred via the diode G to the control winding S1 of the transfluxor.

Instead of restoring the driver core via the winding W3, the restoration may also be etfected via the winding W1 by the application of pulses of an opposite polarity.

With reference to FIGURE 2, first of all the case according to which the driver core K1 is operated in both resaturation directions by impulses has been discussed, so that in the coupling loop between the driver core and the transfiuxor the transmission pulse had been suppressed in the restoring direction by the action of the diode G. According to a further embodiment of the invention, however, the coupling circuit between the driver core and the transfluxor can be completed in both directions of the current flow, when taking care that the restoring of the driver core or its setting is performed so slowly that the change in flux with respect to time in the output winding W2 will only affect an output signal of such a small amplitude that this pulse will remain ineffective with respect to the transfluxor.

One such type of circuit arrangement is shown in FIG- URE 3 of the accompanying drawings. The cores K1 and K2 again are provided with the same windings as in FIG- URE 2, with the exception that in this case the output Winding a2 of the transfluxor has been omitted. In parallel with the input winding W1 of the driver core there is connected a capacitor C, the one plate of which is applied directly and the other plate of which is applied via the diode D to the terminals of the lead-in conductor e1.

Also in this case it is assumed that in the initial condition the driver core K1 and the transfluxor K2 are in the state of negative remanence. Now when applying an alternating current from a source of small internal resistance to the lead-in e1, the capacitor C will be charged. In the course of this charging a direct current will gradually appear in the winding W1, by means of which the core K1 is relatively slowly resaturated. Subsequently to the cutting-off of the source of alternating current from e1, the core K1 will remain in the state of positive remanence. During the resaturation of the core K1 a current proportional to the flux variation do/dt will flow in the coupling circuitconstituted by the winding W2 and S1. This current is so small that the state of remanence of the transfluxor will remain unchanged, i.e. that the transfluxor will remain unoperated. When returning, the driver core to the output or starting condition by a strong pulse via the input winding W3, then an output pulse will be transmitted from W2 and S1 and the transfluxor will be set accordingly. In the case of a new blocking of the transfluxor, care will have to be taken that its restoring to the condition or state of negative remanence will remain without influence upon the driver core K1. For this reason it is of advantage to limit the restoring current, as applied to the control winding S2, in such a way that the change in flux will only beeflfected slowly during the resaturation, and that only correspondingly small currents will be induced in the coupling circuit between K1 and K2. If it is intended to operate the blocking of the transfluxor likewise with the aid of strong pulses, then, by means of a corresponding attenuator or damping element in the coupling circuit between W2 and S1, the reaction of the transfluxor upon the core K1 will have to be limited correspondingly, by taking e.g. from the output of K1 a high voltage versus time integral, and by feeding only a fraction thereof to the setting winding S1 of the transfluxor, so that, in the other way round, the voltage versus time integral as supplied upon blocking of S1, will also only be transferred to a small extent to the winding W2.

In the set condition or state, just like in the circuit arrangement according to FIGURE 2, upon application of an alternating voltage to the call-up winding e, a useful signal may be taken from the transfluxor via the readout winding a.

In FIGURES 4 to 7 various embodiments suitable for the construction of shifting registers consisting of circuit arrangements according to the invention are shown. The shifting register as shown in FIGURE 4- is composed of circuit arrangements according to FIGURE 2. For each register stage there is provided one single apertured driver core and one transfluxor, of which respectively two are shown in FIGURE 4. According to a further embodiment of the invention the output winding a2 of the transfiuxor of the one stage is respectively connected via a diode G1, permitting a passage in the shifting direction, with the input winding W1 of the driver core of the next successive stages. The control winding S2 of the transfluxors and the input windings W3 of the driver cores of all stages are respectively separately connected in series, and are connected with two stepping or transfer lines 121 and 12.

This arrangement is operated in such a way that the stepping or transfer pulses are alternately applied to the stepping or transfer lines p1 and p2. Thus by means of a first stepping or transfer pulse on the line p1, all transfluxors are blocked simultaneously. If one of the transfluxors, prior to the blocking, has been in the set condition, then, via the rectifier G1, an output signal is transmitted from the output winding a2 of this transfiuxor to the input winding W1 of the next successive driver core, so that the information previously stored in the transfluxor is transferred to this core. By the following second stepping or transfer pulse on the line p2, the driver core is then returned to the initial condition again and, in the course of this operation, an output signal is transferred to the next successive transfluxor via the diode G, so that the latter will be set thereby. Therefore, if, for instance, prior to the blocking, the transfluxor Kt had been in the set condition, then K0 will be blocked by the first stepping or transfer pulse and the driver core K1 will be resaturated. By the action of the second stepping or transfer pulse, K1 will be resaturated and the transfluxor K2 will be set. However, if prior to the blocking, K0 had not been set, then the first stepping or transfer pulse, i.e. effecting the blocking of K2, will not effect a change in flux in K0 and, consequently, no resaturation of K1, so that after the second stepping or transfer pulse has been applied to the line p2, K1 is prevented from being resaturated and, in consequence thereof, will also not transmit an output signal for the setting of K2.

By the stepping pulses or transfer pulses on the lines p1 and p2, the stored informations are alternately transmitted from the transfluxors into the driver cores, and from these again to the next successive transfluxors. In the course of this operation the information is tapped at the transfluxor, if the transfluxor is blocked.

However, the arrangement can also be made in such a Way that the tapping of the information at the transfluxor is effected together with the withdrawal or extraction of the useful signal (reading signal). A correspondingly designed shifting register is shown in FIGURE 5. Also in this arrangement one transfiuxor and one single-apertured driver core is provided for each register stage, the circuit arrangement of which corresponds to the circuit according to FIGURE 3. The coupling of the individual stages is carried out in this embodiment according to the invention in such a way that the readout winding a of the transfluxor of the one stage is connected with the leadin el of the driver core of the next successive state, and in that in each case the control windings S2 of the transfluxors and the input windings W2 of the driver cores of all stages are separately connected in series for forming one stepping or transfer line p1 or p2 respectively. For the operation of this circuit arrangement and for each stepping or transfer process, a first stepping or transfer pulse is fed to the one stepping or transfer line p1 serving the blocking of the transfluxors of all stages, and thereupon, a second stepping or transfer pulse is fed to the other stepping or transfer line p2 serving the interrogation or calling-up of the driver cores, and the corresponding setting of the transfluxors.

In order that no information is lost between two successive stepping or transfer processes, it is necessary to feed to the input or call-up windings e of all transfluxors an alternating-current voltage for tapping a useful signal at the output end via the windings a and for effecting the direct current setting of the driver cores via the diodes D and the capacitors C, as well as via the windings W1. Accordingly, this circuit arrangement will be mainly employed in this particular application when a reading cycle follows each stepping or transfer process.

In accordance with the further embodiment of the invention the coupling loops between the driver core and the transfluxtor may also be laid out in such a way that the shifting registers which are constructed of the transfluxor circuit, can be operated with one stepping or transfer line only. To this end it is of advantage to insert into the coupling loop, i.e. between the output winding W2 and the control winding S1, and after the rectifier G, a time-delay circuit LC. In FIGURES 6 and 7 there are shown correspondingly designed shifting registers. In the shifting register according to FIGURE 6, which is laid out for the pulse setting of the driver core, a time delay circuit LC is arranged in the coupling loops after the rectifiers G, and after the rectifiers G1. The control windings S2 of the transfluxors and the input windings W3 of the driver cores are alternately connected in series, thus forming a common stepping or transfer line p. By the application of stepping or transfer pulses, all of the transfluxors will be simultaneously blocked, and all of the driver cores will be interrogated. If one transfluxor prior to the blocking had been in the set condition, then an output signal is fed via the rectifier to the subsequently arranged timedelay element LC, and subsequently to the decay of the stepping pulse, this output signal is stored in the subsequently arranged driver core. If, on the other hand, in one of the driver cores an information had been stored, then an output signal will be produced by the stepping pulse, which is fed, via a diode G, to the subsequent time-delay circuit LC, for effecting the setting of the subsequently following transfiuxor via the control winding S1 subequently to the decaying of the stepping pulse.

Such a shifting register according to the invention may be fundamentally operated in two different ways. The first mode of operation requires two stepping pulses for each stepping or transfer process, which are successively applied to the stepping or transfer line p. In the course of this operation the driver cores merely serve as auxiliary cores or intermediate storage devices, while the actual signal or useful information is only stored in the transfluxors. By the action of the first stepping pulse the total useful signal is transferred from the transfluxors to the driver cores, and in the course of a second stepping cycle, again from the driver cores back to the transfluxors. In the course of this operation, and after the first stepping pulse, and subsequently to the restoring process which is delayed by the time-delay elements, the information contents of all transfluxors is zero, and after the second stepping pulse, the information contents of all driver cores is zero. In this manner of operation, the shifting register operates with respectively one driver core and one transfluxor per hit.

However, in a second manner of operation, this shifting register may also be operated in such a way that one bit is stored per driver core and one per transfluxor. In this case, with respect to a shifting register, according to FIGURE 6, only every second bit is capable of being read in a non-destructive manner. Fundamentally, such a shifting register corresponds to a shifting register employing normal types of cores, in which likewise one core per bit is provided. In many cases, the requirement that each stage of the register is capable of being read does not even exist. In many cases, the read-out of the last stage of the register is all that is required. In other cases, for instance the binary multiplication of dual numbers with the factor 10, represented in a serial notation, it is only necessary to said the n and the (n--2) register stage. However, in this case Only these two stages will employ transfluxors instead of normal types of cores. In this form the circuit arrangement according to the invention may be employed with all cases of practical application where the reading points are not lying in directly adjacent register stages.

A further embodiment with only one stepping line is shown in FIGURE 7. In this shifting register likewise, a time-delay circuit LC is inserted into the couplng loop between the core and the transfluxor and after the diode G, while the direct-current setting of the single-apertured driver core is eifected via the output winding of the transfluxor of the preceding stage in the same manner as with the shifting register according to FIGURE 5. Also in this case one driver and one transfluxor are provided for each register stage, i.e., for each bit. Between two successive stepping pulses a call-up signal has to be fed to the transfluxor via the input winding 2, in order that no information goes astray, because otherwise the transfluxors are merely blocked by the stepping pulses, and the information is called up from the driver cores, but not the information as previously stored in the transfiuxor, i.e. this information is then not transferred to the driver core. Shifting registers of this kind are particularly suitable for employment Whenever each stepping pulse is followed by a reading cycle.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

I claim:

1. A transfluxor circuit, for use in storage devices, counting chains and shifting registers, comprising a transfluxor core having a control winding and an output winding, means for saturating said transfluxor core in one direction of its remanence, a single-apertured magnetic driver core having a rectangular hysteresis loop and having an input winding and an output winding, means for saturating said driver core in one direction of its remanence, means for applying resaturation pulses to said input Winding of said driver core of sufficient amplitude to saturate said core in the opposite direction, means for connecting said output winding of said driver core and said control winding of said transfluxor core in a circuit closed at least in one direction of current flux, so that a signal having a. predetermined voltage versus time integral characteristic will be fed to said control Winding of said transfiuxor at least during the one resaturation of said driver core by virtue of the non-critical saturation and resaturation action of said driver core.

2. A circuit arrangement, as claimed in claim 1, in which both the driver and transfluxor cores consist of the same kind of material.

3. A circuit arrangement, as claimed in claim '1, in which the circuit arrangement is so dimensioned that the product of the cross-section of the driver core at the out- 8 put winding and the number of turns thereof has the relationship to the product of the cross-section of the transfluxor core at the control winding thereof and the number of turns of said control Winding as 12211, wherein n denotes the number of resaturations which are necessary for effecting the setting of said transfiuxor core.

4. A circuit arrangement, as claimed in claim 1, in which the product of the cross-section of the driver core at the output winding thereof and the number of turns of said output winding is half as big as the product of the cross-section of the transfluxor core at the control winding and the number of turns of said control winding, so that said transfiuxor is capable of being set by only one resaturation of the driver core.

5. A circuit arrangement, as claimed in claim 4, in which the input winding of the driver core is used for feeding-in the resaturation pulses of the other direction, the means for saturating said driver core in the one direction comprising a second input winding for feeding-in saturation pulses, and in which the control winding of the transfluxor core is for receiving the setting pulses of the other resaturation direction, and the means for saturating said transfiuxor core in the one direction comprising a second control winding for feeding-in the saturation pulses.

6. A shifting register, as claimed in claim 5, further comprising a diode in each stage in the connecting means between the driver core and the transfluxor, and a timedelay circuit connected between, each diode and the associated transfluxor core, and in which the means for connecting the control windings and the input windings of all stages are connected in series for forming one common transfer or stepping line circuit.

7. A circuit arrangement, as claimed in claim 5, in which the means for applying the resaturation pulse to the input winding of the driver core comprises a diode connected in series with said input and a capacitor connected in parallel across said input winding at the juncture of said winding and said capacitor, whereby alternating current may be applied to said input winding.

8. A shifting register comprising circuit arrangements, as claimed in claim 7, in which there are a plurality of register stages, there being one transfiuxor core and one single-apertured driver core for each stage, means for connecting the output winding of the transfiuxor of each stage with the input winding of the driver core of the next successive stage, means for connecting the second control windings of the transfluxors in series to form one stepping line, means for connecting the second input windings of the driver cores of all stages in series to form one transfer line, the means for saturating the transfiuxors and the driving cores comprising means for feeding a first step ping pulse to the one stepping line for effecting the saturation of the transfiuxors of all stages and means for thereupon feeding a second stepping pulse to the transfer line for effecting the interrogation of the driver cores and for the corresponding setting of the transfluxors.

9. A circuit arrangement as claimed in claim 5, further comprising a diode connected in the circuit connecting the output winding of the driver core and the control winding of the transfiuxor core to permit transfer of the setting pulses in the forward direction.

10. A circuit arrangement, as claimed in claim 9, in which the transfiuxor core is provided With an additional output winding, surrounding the smallest cross-section of said core which is used for the setting purpose, so that at this winding output pulses may be tapped when the transfiuxor is resaturated.

11. A shifting register comprising circuit arrangements, as claimed in claim 10, in which there are a plurality of register stages, there being one single-apertured driver core and one transfluxor core for each register stage, means including a diode, conductive in the shifting direction, for connecting the output winding of the transfluxor core of each stage with the input winding of the driver core of the next successive stage, means for connecting the second control windings of said transfluxors in series to form one stepping line, and means for connecting the second input windings of said driver cores in series to form one transfer line, the means for saturating the transfluxors and the driving cores comprising means for feeding pulses alternately to said stepping and transfer lines.

12. A shifting register, as claimed in claim 10, further comprising a time delay circuit included in the connecting means between the transfluxors and the driver cores, and between the driver cores and the transfluxors, after the diode and in which the means for connecting the control winding of the transfiuxor core and the input winding of the driving core of all stages connects the Winding in series, so that they will form one common stopping or transfer line.

References Cited UNITED STATES PATENTS 3,068,462 12/1962 Medofi 340-174 BERNARD KONICK, Primary Examiner.

I. W. MOFFITT, Examiner.