US3538318A

US3538318A - Wear weighting function generator for the determination of the proper aiming of a gun

Info

Publication number: US3538318A
Application number: US754441A
Authority: US
Inventors: Roy G Clutterbuck; Roger H Edelson
Original assignee: Hughes Aircraft Co
Current assignee: Raytheon Co
Priority date: 1968-08-21
Filing date: 1968-08-21
Publication date: 1970-11-03
Anticipated expiration: 1987-11-03
Also published as: NL6911117A; FR2016032A1; FR2016032B1; DE1937093A1; DE1937093B2; GB1219062A; NL158288B; SE357254B; JPS4837720B1; BE737686A

Description

R. G. cLuTTERBucK ET AL 3,538,3 WEAR WEIGHTING FUNCTION GENERATOR FOR THE DETERMINATION OF THE PROPERV AIMING OF A GUN 2 Sheets-Sheet 1 Filed Aug. 2l, 1968 VIIJ.

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WEAR WEIGHTING FUN OF THE PROPER AIMING OF A GUN 2 Sheets-Sheet 2 Filed Aug. 21, 196s U.S. Cl. 23S-193 8 Claims ABSTRACT F THE DISCLOSURE In determination of the proper aiming of a gun, the effects of wear in the gun tube caused by previous rounds must be considered. A firing sensor connected to the gun ring mechanism signals gun firing. An ammunition selector multiplies this gun tiring signal by any selected one of a plurality of gun tube wear factors, depending upon the type of ammunition fired, to result in a gun tube wear factor for that particular round. These factors are totalized so that a counter carries the total wear factor accumulated since the gun tube was new. The counted total is stored in a non-volatile memory. The memory is preferably a ferrite core memory or the like, and the counter is a multibit solid-state counter. The counter output signal is connected to a digital-toanalog converter, the signal of which corresponds to gun tube wear since the gun tube was new, and is employed as a correction factor in the gun fire control computer.

BACKGROUND This invention is directed to a Wear weighting function generator which has an output signal which corresponds to the amount of wear in a gun tube, which signal can be employed as a correction factor in a gun tire control computer.

The velocity of a projectile as it leaves the muzzle of a gun is a function not only of the individual characteristics of the projectile and its driving charge, but it is also a function of the condition of the gun barrel. The change in muzzle velocity due to wear has been previously recognized, and previous gun computers have employed inputs corresponding to Wear for the correction of gun direction. In the previous units, the gunner was required to periodically measure the gun bore, preferably both at the chamber end and at the muzzle end. After he compared these measurements with prescribed standards, he manually made an adjustment on the gun computer in accordance with his findings as to the state of wear. Of course, during battle, wear would proceed without giving the gunner the opportunity for these required periodic measurements. As a result, at the time when correct aiming was most needed, the change in muzzle Velocity due to wear was not continuously updated and inserted into the gun computer, with adverse aiming effects. Other more sophisticated methods have also been attempted.

As an additional factor, gun computers are subject to shocks of high orders of acceleration. The gun shock itself, of course, it not permitted to put out of action the gun computer. Furthermore, a direct artillery hit upon the gunsupporting structure, which does not directly strike the gun computer should not put the gun computer out of service. Thus, those items directly damaged can be replaced and the gun will be back in service. Furthermore, if the hit is not of a critical nature, the gun can remain in service. Such resistance to high accelerations is best accomplished by the use of solid-state circuitry.

nite States aten SUMMARY In order to aid in the understanding of this invention, it can be stated in essentially summary form that it is directed to a wear weighting function generator which totalizes the wear in a gun tube resulting from the firing of a plurality of rounds therethrough, even when the rounds are of diiferent wear-poducing nature, for employing the wear function as a correction in a gun tire control computation. The wear weighting function is generated by input signals representing both the number of rounds, and the wear-producing character of each individual round. These individual round wear factors are totalized in a counter, and a parallel non-volatile memory stores the weighted wear function so that a value corresponding to wear is remembered through power cessation. The output of a counter serves as an effective full charge signal for employment in calculation of change of muzzle velocity due to wear, as a correction factor to the gun re control cornputer.

Accordingly, it is an object of this invention to provide a wear Weighting function generator which employs several inputs, and totalizes them to hold a total count corresponding to the amount of wear in a gun tube. It is a further object to provide a non-volatile storage for the counted total Wear function so that upon power failure, or normal system turn off, the number corresponding to total wear is retained. It is a further object to provide a solid state wear Weighting function generator which is resistant to high accelerations, and still retains its count. It is still another object to provide a counter which totalizes a number corresponding to total wear, together with a parallel memory therefor so that the memory can serve to reset the counter as required. It is another object to provide a ferrite memory as the memory unit. Other objects and advantages of this invention will become apparent from a study of the following portion of the specification, the claims and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a block diagram showing the Wear weighting function generator.

FIG. 2 is a more detailed schematic drawing showing the details of the effective full charge multiplier as it is related to the rest of the generator.

DESCRIPTION The wear Weighting function generator of this invention is generally indicated at 402 in FIG. 1. It is associated with gun 404 which has a bore which wears out upon firing thereof. Presuming that the gun 404 is capable of tiring a plurality of different types of arnmunition, and these different types cause different amounts of Wear for each shot, it is necessary to provide signals relating to the type of ammunition, and relating to the number of firings.

Firing switch 406 is mechanically connected to gun 404 so that it momentarily closes upon each gun firing. Preferably, it is actuated by the recoil mechanism of the gun. Thus, a firing signal is transmitted to the effective full charge rate multiplier 40S upon the firing of each round. Another signal delivered to the EFC multiplier is from ammunition selector switch 410.

Assuming four different types of ammunition to be fired through gun 404, exemplary values of wear rates and wear multipliers are given in the table below:

The number of rounds to wearout, for particular ammunition, is found experimentally. Any convenient means to determine wearout of the barrel can be used, including micrometer measurement of the gun bore, or by change in muzzle velocity, as compared to a new barrel. The least common multiple of the number of rounds to wearout is 3,000. The wear multiplier in the table is the least common multiple divided by the number of rounds of a particular ammunition to wearout. Thus, the wear multiplier is a relative value of wear in the gun barrel, which relates the amount of wear caused in the barrel by the different ammunitions.

With input signals from the firing switch 406 and ammunition selector switch 4.10, the effective full charge rate multiplier multiplies the round red by its wear multiplier. This amount of effective full charge by that particular round is delivered to counter 412 which totalizes the effective full charge units received from the EFC rate multiplier. This amount of effective full charge by that particular round is also applied to the read-write control 424 in order to initiate the write operation, thereby allowing the counter 412 to update the memory 420. Output of counter 412 is delivered to digital-to-analog converter 414, which is similar to the digital to analog converter described in U.S. Pat. 2,993,202 issued July 18, 1961, by signal line 416 so that the output of wear weighting function generator 402 appears in signal line 418 as an analog value. It is suitably employed in a gun fire control computer to compensate aiming in accordance with the total wear of the barrel.

In view of the fact that guns to which such aiming equipment is applied are subject to power failure and are subject to being placed in storage with power shutdown for considerable periods, when counter 412 is of solid state, it normally loses count upon power shutdown. Thus, memory 420, which may be similar to the memory described in U.S. Pat. 2,933,720 issued Apr. 19, 1960, is associated with counter 412 in order to provide the correct count to the counter after such a power shutdown. Power condition detector 422 is connected to the electric power source which serves to retain the count in the counter. Power condition detector 422 is connected to read-write control 424, which is in turn connected to memory 420 for the purpose of providing in the memory a count of the total on counter 412 when power is olf, and for the purpose of writing into the counter the count when power is restored. The power condition detector 422 may be similar to the circuitry shown in FIG. 3 of U.S. Pat. 3,321,747 issued May 23, 1967. Furthermore, the read-write control 424 may be similar to that described and shown from page 19-13 to page 19-21 in volume 2 of the Handbook of Automation Computation and Control published by John Wiley & Sons, Inc., New York (1959). Counter 412 can either update memory 4201 with each count of memory 420 can be connected to interrogate counter 412 upon incipient power failure and store the memory in the counter. Memory 420 is preferably a ferrite core memory, although any convenient memory system can be employed.

`Referring to FIG. 2, a schematic diagram in more detail of the effective full charge multiplier is shown therein, in connection with associated equipment. Clock 426 either generates a square wave of appropriate frequency, or squares off an available frequency. In some equipment with which the wear weighting function generator is employed, 400 cycle alternating current is available. In such cases, clock 426 need only square the available freqency. The output from firing switch 406 and clock 426 are inputs to AND gate 428. The output of AND gate 428 goes to OR gate 430. The output of OR gate 430 is connected to counter 432.

In the example illustrated, counter 432 is a four-bit counter capable of counting to 16. The four outputs from the four bits of counter 432 are connected to OR gate 434. The output of OR gate 434 is connected to AND gate 436 which also receives the clock signal as an input thereto. The output of AND gate 436 is the other input to OR gate 430. Counter 432 has at least one high state output whenever the count thereon is other than zero. Thus, as long as the count is other than zero, there is a signal to OR gate 434, which provides energization to AND gate 436 so that the clock pulse passes through OR gate 430 to keep the counter 432 counting. This continues until the full count of 16 is made by the counter, when all of the counter outputs are at zero so that there is no output from OR gate 434 into AND gate 436. Thereupon, the counter stops until the next firing switch energization. This system provides 16 pulses in line 438 each time tiring switch 416 is actuated.

Line 438 is connected to the input of binary sealer 440 which has

sections

442, 444, 446, and 448, which may be bistable multivibrators or flip-flops. Thus, each time counter 432 goes through its 16 counts, it delivers 8 counts to AND gate 452, 4 counts to AND gate 454, 2 counts to AND gate 456, and 1 count to AND gate 458. The ammunition selector switch 410 is connected to each one of AND gates 452 through 458 so that the number of counts desired can be selected by selecting particular ones of the AND gates.

The following table indicates the switch pattern of the ammunition selector switch to obtain the desired number of counts. To accomplish this switch pattern, the ammunition selector switch 410 may comprise four manually operable two-position switches (not shown), each having a "0 output when open and a l output when closed. The switch pattern indicates the high or low state of the lines from the ammunition selector switch to AND gates 452 through 458, reading from top to bottom in FIG. 2.

The outputs of AND gates 452 through 458 are connected to OR gate 460 so that the output is totalized and the signal into line 416 is the effective full charge count for the round just fired, and as previously stated, this is delivered to counter 412 through signal line 462 to add to the count on counter 412 the factor corresponding to wear for the firing of the latest round. As a round having a different wear factor is loaded, the ammunition selector switch 410 is changed to a position corresponding to the new round, so that upon ring thereof the wear factor for that round is totalized in counter 412.

This invention having been described in its preferred embodiment, it is clear that it is susceptible toi numerous modications and embodiments within the ability of those skilled in the art and without the exercise of the inventive faculty. Accordingly, the scope of this invention is defined by the scope of the following claims.

What is claimed is:

1. A wear weighting function generator for totalizing and emitting a signal corresponding to wear caused on a unit by separate acts which each cause a different but predetermined amount of wear on the unit, said wear weighting function generator comprising:

a detector for detecting an act on the unit;

a selector for selecting a value related to the amount of Wear caused by the act on the unit;

a multiplier, said detector and said selector being connected to said multiplier so that the multiplier multiplies the number of acts times the value related to the amount of wear;

a counter, said multiplier being connected to said counter so that said counter totalizes the products received from said multiplier;

a memory connected to said counter, said memory 5 storing the count of said counter so that upon loss of count by said counter said memory can reset said counter, said counter emitting a signal corresponding to the number of acts causing wear on said unit each times its wear factor so that the emitted signal is related to total wear on said unit.

2. The Wear weighting function generator of claim 1 wherein said counter is a solid-state counter which is subject to loss of count upon power failure, and said memory is a non-volatile memory so that said memory holds the count during periods of power cessation and can reset said counter.

3. The wear weighting function generator of claim 2 wherein a power condition detector is connected to the source of power which powers said counter, said power condition detector .being connected to a read-write control, said read-write control being connected to said memory so that upon power cessation, said memory retains the count of said counter, and upon restoration of power, said power condition detector causes said memory to reset said counter to the remembered value.

4. The wear Weighting function generator of claim 3 wherein said unit is a gun capable of tiring different ammunitions which cause diierent amounts of wear, said detector is a firing switch which is connected to said gun and detects each tiring of said gun, and said selector is an ammunition selector switch which is settable to different values in accordance with the relative wear of the different types of ammunition rable by said gun, so that the signal emitted by said counter is related to the total amount of wear in said gun.

5. The wear Weighting function generator of claim 1 wherein said multiplier comprises a counter, said act detector and a clock having an input to said counter, the output of said counter being connected to the input of said counter so that said counter counts to one more than its full count and thereupon stops so that the input to said counter receives as many pulses as the full count of said counter, a binary Scaler connected to the input of said counter, said binary scaler having a plurality of outputs, each emitting a number of counts, said outputs of said scaler being connected to scaler output AND gates, said selector being connected to said Scaler output AND gates to energize particular ones of said scaler output AND gates, the outputs of said Scaler output AND gates being summed together in a summer so that said selector selects the number of counts out of said summer.

6. The wear weighting function generator of claim 5 wherein there are iirst and second AND gates, said clock being connected to said rst and second AND gates, said detector being connected to said rst AND gate and the output of said counter being connected to the input of said second AND gate, the outputs of said rst and second AND gates being connected together to a counter input OR gate, 4with the output of said counter input OR gate being connected to the input of said counter, the output of said counter input OR gate being also connected to the input of said binary scaler.

7. The wear weighting function generator of claim 6 wherein said unit is a gun, and said detector is a ring switch which emits a signal each time said gun is iired so that upon gun tiring said counter is energized through said rst AND gate.

8. The wear weighting function generator of claim 7 wherein said selector is an ammunition selector switch connected to said scaler output AND gates so as to energize appropriate of said Scaler output AND gates in accordance with the relative wear of a particular type of selected ammunition tired in said gun.

References Cited UNITED STATES PATENTS 3,102,451 9/1963 Campbell 89-41 3,136,992 6/1964 French 89-41 X 3,260,107 7/1966 Rosen 73-167 3,313,209 4/1967 Thompson 89-41 3,339,457 9/1967 Pun 235-6l.5 X 3,405,599 10/ 1968 `Barlow et al.

3,443,476 5/ 1969 Heider et al.

MALCOLM A. MORRISON, Primary Examiner I. F. RUGGIERO, Assistant Examiner U.S. Cl. X.R.