US2750553A

US2750553A - Electric control system for supervising relatively movable members

Info

Publication number: US2750553A
Application number: US221786A
Authority: US
Inventors: Andersson Karl Nial
Original assignee: Bofors AB
Current assignee: Saab Bofors AB
Priority date: 1950-04-28
Filing date: 1951-04-19
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12

Description

June 12, 1956 K. N. ANDERSSON ELECTRIC CONTROL SYSTEM FOR SUPERVISING RELATIVELY MOVABLE MEMBERS Filed April 19, 1951 2 Sheets-Sheet l Fmg. E

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ELECTRIC CONTROL SYSTEM ECE suPERvTsTNC RELATIVELY MOVABLE MEMBERS Filed April 19, 1951 2 Sheets-Sheet 2 Fmg. E

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KARL N I AL AN DERSSON [gy/ETAM? ATTORN EY ELECTRIC CONTROL SYSTEM FOR SUPERVIS- ING RELATIVELY MOVABLE MEMBERS Karl Nial Andersson, Grondal, Sweden, assignor to Akgiebolaget Bofors, Bofors, Sweden, a corporation of weden Application April 19, 1951, Serial No. 221,786

Claims priority, application Sweden April 28, 1950 7 claims. (ci. sis- 468) This invention relates to electric control systems for supervising the movements of two members movable relative to each other and disposed in close proximity. More particularly, the invention relates to electric control systems for supervising the relative movements of elongated members, such as gun barrels, which are so mounted that there is a danger of physical contact or collision between the elongated members.

A control system of the general type, above referred to, is useful in many iields of application. A particularly useful though not exclusive eld of application is the supervision of the aiming movements of guns or gun batteries on naval craft. The available space on warships is often so limited that the guns must be mounted so closely together that the gun barrels can collide in certain relative positions which is of course highly undesirable, or that the discharge from one gun will strike the barrel of another gun which is equally undesirable. To avoid accidents of this nature, a member of a gun crew is frequently detailed to watch the movements of the gunbarrels and to stop the barrel movements by a suitable control device when there is a dangerous approach between the barrels. Such reliance upon a person is not very satisfactory since it involves human reaction, subjective judgment, and the danger that the detailedl crew member becomes incapacitated during an engagement just at a critical moment. l.

Accordingly, one of the principal objects of the present invention is to provide a control system which continuously and automatically supervises the relative positions of the gun barrels or other elongated members.

Another object of the present invention is to provide a novel and improved control system which is continuously controlled by the movements of the gun barrels or other elongated members and which automatically initiates corrective measures if there is a danger of collision or, more generally, a dangerous approach between the gun barrels.

Other objects, features and advantages will be pointed out hereinafter and set forth in the appended claims forming part of the application.

In the accompanying drawing a now preferred embodiment of the invention is shown by way of illustration and not by way of limitation.

in the drawing:

Fig. 1 shows diagrammatically two elongated members movably relative to each other in one plane.

Fig. 2 is a diagram illustrating the range of the relative positions within which a collision between the two members is feasible.

Fig. 3 is a typical circuit diagram of an electric control system according to the invention.

Fig. 4 is a graph showing the function of the system according to Fig. 3, and

Fig. 5 is a modification of the circuit diagram of Fig. 3.

Referring first to Fig. 1 in detail, this ligure shows two gun barrels or other elongated members indicated by the two solid lines 1 and 2. These lines (or barrels) should nited States atent be visualized as being movable in the plane of the drawing and pivotal about the points A and B respectively. The curves which the free ends of the lines 1 and 2 describe when the barrels are pivoted, are indicated by OA and OB. The line which connects the intersecting points of the two curves OA and OB is designated by DE. Let it now be assumed that the two lines are in the positions shown on Fig. 1 in full lines. Then, they will intersect with each other at the point C on the connecting line DE. Let it be further assumed that the two members represented by lines 1 and 2 are for practical purposes very nearly in the same plane. The angles of the lines relative to the horizontal line AB are designated a and If, now, one of the lines, for instance line 1, remains stationary while the other line 2 is moved within the same plane as the line 1, it will be found that line 2 will collide with line 1 when the line 2 approaches the line 1 from below and reaches the position indicated by the dashed lines 6. Similarly, line 2 will collide with line 1 when line 2 approaches line 1 from above and reaches the position indicated by dashed line 5. It can geometrically be shown that the angles Ai and Az, which lines 5 and 6 form with line 2 when this latter line intersects with point C, have the same value and are identical with the angles Aon and Aam between line 1 and dashed

lines

3 and 4 when line 2 remains stationary and line 1 is movable in the same plane as line 2. If the two lines 1 and 2 are moving at the same time in the curve as drawn following the variations of angles Aa and a, it will be found that such curve assumes the form of a double loop 7.

Fig. 2 shows loop 7, the angles a being entered on the ordinate and the angles on the abscissa. The loop 7 indicates that a collision between the two barrels represented by lines 1 and 2 can occur Within the area defined by loop 7.

A similar loop is obtained when it is assumed that the barrels represented by lines 1 and 2 are movable in a plane perpendicular to the plane of the drawing instead of in this plane. For high values of the angles a and ,8 in the last mentioned plane, a curve following the variations of Aa and A in the first mentioned plane would take the form of a small double loop 8. Consequently, a collision between the two barrels movable in two planes perpendicular relative to each other can be avoided by means of a device for each plane which is so designed that it indicates when either of the barrels or lines 1 and 2 reaches an angular position within the area dened by the double loop. However, it has been found in practice that indicating devices with a sensitivity characteristic which represents a double loop, are unnecessarily complicated.

According to the present invention, two tangents are drawn parallel to each other corresponding to the maximal width of a double loop as is shown in Fig. 2 for double loop 7. As will be noted, the parallel tangents are tangential with the two loops of the double loop. lf, now, a device be designed which indicates or otherwise reacts when one of the two barrels or lines 1 and 2 reaches an angular position within the area defined by two tangents, such a device will satisfy all practical requirements for avoiding a collision between the two barrels.

A device ofthis type can be simply and reliably manufactured and in Fig. 3 is shown a now preferred embodiment of such a device or control system.

The control system according to Fig. 3 comprises two potentiometers having resistors 12 and i4 respectively, and movable or

slidable contacts

13 and 15 respectively. The two potentiometers are preferably of identical resistance value. The two

resistors

12 and 14 are connected at both ends to the

terminals

16 and 17 of a source of D. C. current; The position of contact 13 is controlled by the elevational position of the barrel of a gun 35. The gun is mounted on a platform 36 and elevated or depressed in a conventional manner by the rotation of a shaft 37 extending through the platform and rotated by electric drive means 33. The rotation of shaft 37 is linearly transmitted to slidable contact 13 by suitable conventional transmission means shown as a pinion 39 and a rack 40. The position of slider contact 15 is similarly controlled by the elevational position of the barrel of a gun 35 and the mechanism is designated by the same reference numerals though primed. lt is assumed that the barrels of the guns are moved relative to each other in the plane of the drawing.

As is apparent that the voltage which is tapped by

contacts

13 and 15 from the

resistors

12 and 14 respectively, is directly proportional to the angle between barrels 1 and 2 respectively and the horizontal reference line AB. As a result, the two angles are measured from the right side of the two points A and B or from the left side of these two points. if the two potentiometcrs are identical, the same position of

contacts

13 and 15 will represent the same angle of the barrels of

guns

35 and 35. It will be obvious from the previous explanation that the two potcntiometers are in eiect angle detecting means and that it' is also quite possible and in some instances preferable, to use other types of detecting means such as variable transformers.

Contact 13 is connected to a point 21 which forms the junction point between the two inner ends of two

resistors

18 and 19 connected in series. The two outer ends of the resistors are connected to a D. Cv. source 2t) and also to one side of two

rectifiers

22 and 23 connected in opposition in series.

It will be apparent that the rectiliers can be replaced by polarized relays as is shown in Fig. 5 more fully explained hereinafter.

The junction point 24 between the two rectiiiers 22 and 23 is connected to slidable contact 15. This connection includes a coil 25 of a polarized relay which has two xed contacts 27 and controls a movable contact 26 normally biased into a neutral position. The contacts 27 are connected to a terminal 29, Contact 26 to a terminal 28.

Terminals

23 and 29 are connected through a source of power 41 to the coil of a relay 42 the armature 43 of which controls switch

contacts

44 and 44 respectively. These switch contacts are included in the circuit connections of drive means 35 and 33 respectively with a common power line 45.

The control system according to Fig. 3 further includes indicating means for indicating the angular positions of the gun barrels. These indicating means which may be a conventional design are not shown in detail. but they should be visualized as being connected to terminals 33 and 34. For the purpose of controlling the indicating means a second polarized relay is provided which includes a coil 30 connected to

slidable contacts

13 and 15. Coil 30 controls a movable contact 32 which coacts with a xed contact 31 and is normally biased into a disengaged position.

The` operation of the control system, as hereinbeforc described, is as follows: Let it be rst assumed that the two

slidable contacts

13 and 15 are in the same position on the

respective resistors

12 and 14. This means that the two contacts indicate the salme angle of the barrels of

guns

35 and 35 and that, hence, these barrels are parallel one with the other and point into the same direction. As a result of these equal positions of the contacts, no current will ow between the two contacts as they tap the same voltage. Let it now be assumed that the angular position of the barrel of gun 35 is slightly changed and that as a result contact 13 is moved a little toward the right. Then, there will be a voltage difference between the two contacts. However, no current can tlow between the two contacts as yet due to the voltage drop over resistor 18 and also due to the blocking effect of rectifier. P'

CII

23. When, now, the movement of the barrel of gun 35 is continued and contact 13 is further moved to the right, current will begin to tlow between the two contacts as soon as the voltage difference between the two contacts exceeds the voltage drop.

Similarly, if contact 15 had been moved to the right, no current between the two contacts can How duc to the voltage drop over resistor 19 and the blocking effect of rectifier' 22 until the voltage diiference exceeds the voltage drop over resistor 19.

,lt will also be apparent that when both slidable contacts are moved, the flow of current will begin when the two contacts reach a relative position in which the voltage dierence between them exceeds the voltage drop over

resistors

18 and 19 respectively.

The resistance values of resistors 1S and 19 arc prei-V erably so selected so that the voltage drops across the resistors are equal. As a result, the tlow of current will begin and the relay coil 25 will be energized when the absolute value of the difference between the an gul ai' positions of the two barrels exceeds a certain value which is determined by the voltage drops across thc resistors 15) and 19.

As previously described,

contacts

26 and 27 which are controlled by coil 25, control the operating mechanisms of the gun barrels through relay 42,

switch contacts

44, 44 and drive means 33, 38. These operating mechanisms can be so designed in a manner well understood in the art that as soon as the flow of current begins and the relay coil 25 is energized, the moving mechanisms impart to the barrels such movements that the barrels are moved into a parallel position or into any other position in which a collision between the barrels is avoided. It is also possible to arrange the moving mechanisms so that a further movement of one barrel is stopped and that the other barrel is so moved that it is turned away from the first barrel. Of course, various other arrangements of the moving mechanisms are possible. lt is believed that it is not essential to the understanding of the invention to explore all possible arrangements. lt sufces to say that the arrangement should be so that the moving mechanisms prevent a dangerous approach of the two barrels when relay coil 25 is energized.

The graph according to Fig. 4 shows the current tlow over the control system as a function of the difference in the angular positions of the gun barrels.

The width of the control zone in Fig. l can be varied by varying the voltage drops across the

resistors

18 and 19. Generally, the zone is given the relative width as shown in Fig. 1. However, if the elongated members are gun barrels it is preferable to make the zone wider to prevent also that a discharge from one gun barrel may strike or come close to the other gun barrel.

The second polarized relay which controls the indicating means connected to the terminals 33 and 34, is controlled by the direction of the flow of current between the

slidable contacts

13 and 15.

The circuit diagram of Fig. 5 is generally evident from the previous description. As is apparent rccticrs 22 and 23 of Fig. 3 are replaced by

coils

22 and 23 of two polarized relays. One or the other of the relay coiis will actuate the respective switch contacts 26' and 29', dependent upon the direction of flow of current through the control circuit. In other words, the polarized relays of Fig. 5 perform the function of the polarized relay 25 of Fig. 3.

For the purpose of supervising the movements of the gun barrels or other elongated members in the plane vertically to the drawing, that is, the azimuth movements of the gun barrels, a second control system identical with the described one is provided, the slidable contacts of which are controlled by the azimuth turning of the gun barrels.

Whilethe invention has been described in detail with respect to a certain now preferred example and embodiment of the invention it will be understood by those skilled in the art after understanding the invention, that various changes and modiiications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an installation of the cl-ass comprising two elongated members each pivotally mounted for angular movements relative to a common reference plane and to each other, the said members being disposed in a spacial relationship in which the two members are capable of approaching each other beyond a predetermined limit of approach, the combination with a safety control system comprising two sources of a variable potential, each of said sources being connected with one of said members for control of the respective potential by the angular position of the respective member relative to the said reference plane, control circuit means including two series connected sources of a liXed potential and two unidirectionally conducting electric means series connected in opposition, one of said sources of a variable potential being connected to the connection point between the sources of a iiXed potential of the control circuit means and the other of said sources of a variable potential being connected to a connection point between the two uni-directionally conducting electric means, the respective one of the said electric means becoming conductive in response to a tlow of potential between the two variable sources of potential and through said control circuit means in one or the other direction, the direction of the said flow being controlled by the relative angular position of the two members, and electric controlled circuit means for controlling the relative movements of said members and controlled by the conducting one of the two uni-directionally conducting electric means.

2. In an installation of the class comprising two elongated members each pivotally mounted for angular movements relative to a common reference plane and to each other and a moving mechanism for moving the two members relative to each other, the said members being disposed in a spacial relationship in which the two members are capable of approaching each other beyond a predetermined limit of approach, the combination with a safety control system comprising two sources of a variable potential, each of said sources being connected with one of said members for control of the respective potential by the angular position of the respective member relative to the said reference plane, control circuit means including two series connected sources of a fixed potential and two uni-directionally conducting electric means series connected in opposition, one of said sources of a variable potential being connected to the connection point between the sources of a fixed potential of the control circuit means and the other of said sources of a variable potential being connected to a connection point between the two uni-directionally conducting electric means, the respective one of the said electric means becoming conductive in response to a ow of potential between the two variable sources of potential and through said control circuit means in one or the other direction, the direction of the said ow being controlled by the relative angular position of the two members, the said uni-directionally conducting electric means being arranged to become conductive in response to a difference in potential above a 6 predetermined minimum value, and electric controlled circuit means for controlling the relative movements of said members and controlled by the conducting one of the two uni-directionally conducting electric means.

3. A control system as delined in claim 2, wherein the said two sources of a variable potential each comprise potentiometer means connected in circuit with a source of current, the variable contacts of the said potentiometer means being operatively coupled with the said members for movement of the same and electrically connected to the connection point between the two sources of a fixed potential and the two uni-directionally conducting means respectively.

4. A control system as dened in claim 2, wherein the said two sources of a Xed potential comprise two resistance means connected in series with a source of current.

5. A control system as dened in claim 2, wherein the said two uni-directionally conducting electric means comprise two rectifying means connected in series opposition, and wherein the said electric control means comprise polarized relay means, the said relay means including coil means included in the circuit connection between the connection point of the two rectifying means and the respective source of a variable potential and two switch means each connected in circuit with said controlled circuit means for controlling the relative position of said members, the said coil means causing actuation of one or the other of said switch means for control of the said controlled circuit means when one or the other of the rectifying means becomes conductive.

6. A control system as deiined in claim 5, in combination with additional polarized relay means connected between the two sources of a variable potential and responsive to the direction of a ilow of potential between the said two sources, the said additional relay means being connected in circuit with said controlled circuit means for controlling the relative position of said members.

7. A control system as defined in claim 2, wherein each of the said unidirectionally conducting electric means comprises a polarized relay means including a coil means and a switch means controlled by the energization of the coil means, the said relay coil means being connected in series with each other and the said two sources of a xed potential, the said two switch means being connected in circuit with said controlled circuit means for control of the latter for the puropse aforesaid by actuation of either of the switch means as controlled by the direction of iiow of a potential through the control circuit means.

References Cited in the le of this patent UNITED STATES PATENTS 625,647 Crehore et al. May 23, 1899 1,299,509 Rey Apr. 8, 1919 2,373,208 Trucksess Apr. 10, 1945 2,439,198 Bedford Apr. 6, 1948 2,498,103 Nojciechowski Feb. 21, 1950 2,525,038 Kutzler Oct. 10, 1950 2,583,058 Libman Ian. 22, 1952 OTHER REFERENCES Electrical Engineering, November 1948, p. 1059.