US2754058A - Mechanism for controlling the aiming of ordnance - Google Patents

Description

2 Sheets-Sheet 1 G. A. CROWTHER INVENTOii Geo eAZfred Crowflwr MECHANISM FOR CONTROLLING THE AIMING 0F ORDNANCEI July 10. 1956 Filed May 26, 1957 5Q Z; 2:-,4Jfiw4 H|$ ATTORNEY July 10, 1956 CRQWTHER 2,754,058

MECHANISM FOR CONTROLLING THE AIMING OF ORDNANCE Filed lay 26, 1937 2 Sheets-Sheet 2 SIGHT ANGLE (MINUTES) llllllllllllllllll RANGE (YARDS) TIMEOFFLIGHT(SECONDS) llllllllllllllllllll RANGE (YARDS) CHANGE OF RANGE (YARDS) TIME OF FLIGHT (sacouos) INVENTOR GeorgeALfraZ Crowilwr HIS ATTORNEY United States Patent MECHANISM FOR CONTROLLING THE AIMING OF ORDNAN CE George Alfred Crowther, Manhasset, N. Y., assignor to Sperry Rand Corporation, a corporation of Delaware Application May 26, 1937, Serial No. 144,849

6 Claims. (Cl. 235-615) My invention provides means for continuously generating present range values and for correcting these values to obtain gun ranges and the corresponding sight angles including corrections for such prediction factors as relative movement of the target and the eifect of the apparent wind during the time of flight of the projectile, and which also allow for the effect of ballistic factors due to various particular initial velocities and to an initial velocity loss therefrom.

When a gun of a given calibre is new it causes a projectile to leave its muzzle with a certain initial velocity, and this condition substantially prevails for a prescribed number of rounds the gun is fired. Thereafter, there is a diminution in the initial velocity of the projectile due to gun erosion. There are also other contributory causes such as variances in powder temperature, barometric pressure and projectile characteristics which afiect the initial velocity of the projectile.

The purpose of the herein described initial velocity loss range corrector is to calculate a range correction which will modify the value of a sight angle such that when the deteriorated gun is elevated in accordance with this angle it will have an elevation for a fictitious advance range which will include compensation for the loss in the initial velocity of the projectile.

The novel features include means for converting the evaluations of the time of flight of the projectile for corresponding range values to corresponding range corrections for an arbitrary or unit initial velocity loss, and then proportionally converting the range correction for the unit initial velocity loss to the range correction for the actual initial velocity loss. A further object is to effect the addition of the thus obtained range correction for the actual initial velocity loss to the range prediction due to the change in range during the time of flight. It is a con tinuing purpose to add the sum so efieeted to the present range of the target to secure the gun or advance range and to convert the advance range to a sight angle such that when the deteriorated gun is elevated in accordance with the so determined sight angle the trajectory of the projectile will be compensated for its actual initial velocity loss.

The invention will be understood from the following description in connection with the accompanying drawings in which Fig. l is a diagram of a system embodying my invention;

Figs. 2, 3 and 4 are diagrams showing graphically the function of certain mechanisms in the apparatus.

In using the computing apparatus as a whole, and particularly as shown in Fig. 1, a crank 1 is operated to introduce the initial or observed range obtained from a suitable source, as a range finder. The side 2 of a differential D-9 is connected to the crank 1 and the center 2" of a differential D-9 is thereby positioned in accordance with the existing or initial observed range. This value is generally known as present range. From the center 2" the value of the range is transmitted by a drive 3 to 2,754,058 Patented July 10, 1956 another drive 4, which, in one direction extends to and actuates a present range counter 5. Going also in another direction drive 4 turns a side 6' of a diiferential D-10 proportionately to the value of the present range as indicated by the present range counter 5.

From known calculating means the required values of quantities necessary to certain computations to be performed by the apparatus are available. These calculating means are settable in accordance with the estimated course and speed of the target and the known course and speed of own ship, as well as the direction and velocity of the Wind, both of which are known through'suitable means for measuring them. In consequence of the above referred to settings, the known calculating means determine the values of the component of the range rate due to the targets movement, YT, the component of the range rate due to own ships movement, Y0, and the component of the eifect of the wind in the direction of the range, Yw.

The total range rate, dR, due to the relative movement of the target and own ship, may be ascertained from any of a number of well known means, and may be introduced into the present computing apparatus by a hand crank 7, or automatically from a suitable source of its calculation. In fact, the range rate may, if desired, be obtained from the above referred to known calculating means which determines the values of the quantities YT and Y0, since the range rate, dR=YT+YO.

Operated by the hand crank 7, a drive 8 actuates another drive 9, a pinion 10, which shifts a rack 11 and a ball carriage containing balls 12 in accordance with the range rate, dR, the balls being shifted radially of a disk 13. A constant speed motor 14 operable in accordance with time acts through a drive 15 and a pinion 16 meshing with the toothed periphery of the disk 13 to rotate this disk uniformly according to time. The position of the balls 12 radially of the disk 13 represents the range rate, dR, which is multiplied by the rotation of the disk, the consequent revolution of the balls 12 rotating an output roller 17 in accordance with the change of range AR. The output roller 17 operates a drive 18 and side 2" of difierential D-9 whereby the center 2" of differential D-9 and the drive 3 continuously operate drive 4, present range counter 5 and side 6 of differential D-10 in accordance with the instantaneous or generated value of the present range R.

Consideration of the use of the present range, R, will now be held in abeyance while the calculation of the range prediction that is added to it is discussed.

As previously stated, the range rate, dR equals (Yr-+Yo), and expressed as (Yr+Yo) is transmitted to a side 19' of a differential D-24. Also, the range component due to own ships movement, Yo, and the range component due to the effect of wind in the direction of the range, Yw, are added to give the apparent wind component in range, WR, which is introduced into the present computing apparatus either by the hand crank 20, or automatically, to operate a drive 21. Drive 21 operates gearing 22 which has a-ratio which supplies a constant K1, by which the quantity WR, is multiplied, the product being regarded as K1(Yo+Yw) which is transmitted from gearing 22 to the center 19" of differential D-24. Two needed quantities, RT and Rw may now be obtained, of which Rr=range rate due to the range components of movement of the target and the own ship, multiplied by the time of flight; and

Rw=the total efiect of the wind in the direction of range upon the projectile during the time of flight.

The formulae for these equations are:

RW=-WR(K1TK2) =(Yo-l-YW) (-K1T|-K2) (2) Where Yr-l-Yo: range rate, dR; T=time of flight; WR=total apparent wind in range Yo-l-Yw); and K1 and K2 are constants.

RT and Rw are computed simultaneously in the range predictor, KIWR being subtracted from dR in differential D-24, and their difference constituting a factor which is introduced into the range predictor where it is multiplied by the time of flight, T, to give a product, which, when the quantity KzWn is added thereto becomes the range prediction uncorrected for initial velocity loss, Rrw.

For a more ready comprehension of these mathematical operations the determination of RT and Rw will be undertaken separately, and with range rate, dR, expressed as (YT-I-YQ), and the total effect of the wind in range, WR, as (Yo-I-Yw).

In determining the value of RT, the measure of the range rate (YT+ Yo) is applied, as already stated, to side 19' of differential D-24 to be transmitted through its other side 19", a drive 23 and a pinion 24 to an input sector 25 of the range predictor 26 to angularly displace this sector in accordance with the value of the factor (YT+Yo). Rotatably mounted on sector 25 is a screw shaft 27, which is turned in accordance with the time of flight, T, derived from a source to be subsequently described. A block 28 is slidable in a radial slot 29 in sector 25, the slot being substantially coextensive with the screw shaft. As the screw shaft 27 is threaded through the block 28 and has no longitudinal displacement, the block acts as a traveling nut on which a pin 30 is rigidly mounted. Pin 30 projects through an elongated slot in a cross bar 31 of a link 32 which is pivotally connected at one end to a pivoted arm 33 and at its other end to pivoted output sector 34. This effects a parallel motion of the pivoted arm 33 and the output sector 34 dependent for its magnitude upon the combined displacements of input sector 25 and the block-carried pin 30 as moved in response to the turning of the screw shaft 27. Such displacements produce an approximate multiplication of the range rate (YT-I- Yo) by the time of flight, T. The movement of the output sector 34 resulting from the above described operations corresponds to the product of the above mentioned multiplication, which is RT.

Superimposed upon the multiplication set forth above is another multiplication required in the determination of the value of the quantity Rw, which compensates for the effect of the wind in the direction of the range during the time of flight. Since the hereinbefore described operation of the center 19" of differential D-24 in accordance with the value of -K1(Yo+Yw) is transmitted through the side 19" of the differential and by drive 23 and pinion 24 to the input sector 25, which may now be regarded as being displaced according to the value of -K1(Yo+Yw). This factor is multiplied in the previously described manner by the time of flight, T, which has already been shown to be introduced in the range predictor 26 as another factor. Therefore, in the phase of the operation now under consideration, the output sector 34 is displaced in accordance with K1T(Yo|-Yw), the value of which is transmitted from this output sector by a pinion 35 and a drive 36 to the center 37" of a differential D-26. However, from Formula 2 it is seen that the quantity K2(Yo+YW) must be added to K1T(Yo+YW) in order to determine the value of the quantity Rw. To accomplish this there is a branch drive 38 driven from drive 21 in accordance with (Yo+YW) to gearing 39 which has a ratio that effects a multiplication the product of which gives the quantity K2(Yo+Yw). A continuing drive 40 transmits the quantity K2(Yo+YW) from the gearing 39 to the side 37' of differential D-26 where it is algebraically added to --K1T(Yo+YW) to give The composite effect of the two simultaneous multiplications set forth above causes the output sector 34 of the range predictor 26 to actually be displaceable in accordance with the value of a quantity which is designated Raw, and the algebraic addition thereto in differential D-26 of the quantity K2(Yo+YW) changes the value of R'rw' to that of Raw, which is A range correction for the initial velocity loss of the projectile due to gun erosion and other contributory causes is computed and combined with the range prediction, R'rw, already determined. Inasmuch as the computation of the range correction for the initial velocity loss, Rv, is somewhat involved and requires the determination of the value of the advance range, R2, it will be easier, at first, to recognize that range correction for the initial velocity loss, Rv, is effected by mechanism to be described hereinafter to be available for combination with the range prediction, R'rw, obtained as shown above.

Proceeding along these lines, it is clear from what has gone before that the output side 37 of differential D-26 is operable in accordance with the value of the range prediction, R'rw, and operates a drive 41 and a dial 42 which reads against a fixed index to give a reading of the value of the range prediction, R'rw. Drive 41 displaces a side 43 and the center 43" of a differential D-13 to move the pivoted contact arm 44 into engagement with one or the other of a pair of fixed contacts 45 of a follow-up switch, according to whether the value of the range prediction is increasing or decreasing. Thereupon current flows from one main 46 of a current supply line by conductors 47 and 48 to the contact arm 44, the engaged fixed contact 45, one of a pair of conductors 49 (shown as a single line), through the normally engaged blades of a cut-out switch 50 to a motor 51 designated as the R'rwv motor. The current returns from this motor by conductors 52 and 53, two normally engaged and flexed blades 54 and 55 of a multiple-motor cut-out switch and conductor 56 to the other main 58 of the current supply line.

The R'rwv motor 51 is, therefore, energized and runs to operate a drive 59 which in turn operates another drive 60 that extends in opposite directions. In one direction the drive 60 goes to and actuates the side 61' of a differential D-12 in accordance with the value of the quantity RTWV, which is the sum of the range prediction Raw and the range correction for the initial velocity loss, Rv. The center 61 of differential D-12 is operated in accordance with the quantity Rv, which is subtracted in differential D-12 from R'rwv which is introduced by the side 61. This subtraction prevents the contact arm 44 of the follow-up switch from becoming dissociated with the contact 45 it has engaged until the RTwv motor 51 has run an amount equal to the combined values of the range prediction RTW and the range correction for the initial velocity loss, Rv. The subtraction also takes the quantity Rv from the quantity R'rwv, leaving the quantity RTW, which is the value of the range prediction. The quantity R'rw as obtained from the subtraction is transmitted by a drive 62 from the side 61" of differential D-12 to the other side 43" of differential D-13. Therefore, the operation of side 43" in accordance with R'rw will match the in ut of Raw at side 43' as received from side 37" of differential D-26, when the R'rwv motor 51 has run an amount corresponding to the sum of Raw and Rv, i. e., in accordance with the quanttiy R'rwv.

Now, since the RTWV motor 51 operates drives 59 and 60 in accordance with the quantity R'rwv, the drive 60 duced by the hand crank 64 which turns a drive 65, which sets a dial 66 against a fixed index to indicate the value of the present correction of this nature, drive 65 also operating the side 63 of differential D-11. The result is that the range spot correction, JR, is added to the sum of the range prediction, Raw, and the range correction for the initial velocity loss, Rv. The consequent actuation of the side 63" of differential D-11 gives the total summation of these quantities, which is the complete range prediction, designated as RJTwv. Differential side 63" transmits the complete range prediction, RJTWV, by a drive 67 to the side 6" of differential D- where it is added to the present range, R, that was previously shown to be carried to the side 6' of this differential. Consequently, the center 6" of differential D-10 is operated in accordance with the value of the advance range, R2, and actuates drives 68 and 69 to operate a counter 70 to give a reading of the value of the advance range.

The advance range drive 68 continues to another drive 71 which includes gearing 72 having a ratio that multiplies the advance range, R2, by a constant K3 to get KsRz, which effects the conversion of the advance range, R2, to a straight line approximation of the sight angle, Us. The advance range drive 68 also extends to a worm gear 73 that drives a worm wheel 74 fast on a shaft 75. Also rigidly mounted on shaft 75 is a plurality of sight angle complement cams 76, 77 and 78, each of which furnishes the complement or correction to the straight line approximations of the sight angle Us in accordance with a par ticular force of the powder charge to be used in the gun. For example, cam 76 may be for a powder charge of a given strength that causes the projectile to have a particular initial velocity as it leaves the muzzle of the gun. Cams 77 and 78 are for other individually different powder charges each effecting a particularly different initial velocity of the projectile. Obviously the sight angle, Us, varies for the various initial velocities, and is used in further computation.

Fig. 2 shows three curves plotted against advance range, i. e., the sight angle plotted against advance range, R2, whereby for each curve the difference between the straight line approximation of and the actual sight angle is obtained for different ranges thus determining the contour of each of the three sight angle complement cams. In Fig. 2 a, b and c are the curves for cams 76, 77 and 78, respectively. It will only be necessary to consider the curve a, as curves b and c are utilized in the same Way. The hereinbefore referred to drive 71 continues from the gearing 72 that supplies the constant K3, which converts the advance range R2 to the straight line approximation of the sight angle, Us, toextend to and operate the side 79 of a differential D-101 in accordance with such approximation.

This straight line approximation is indicated in Fig. 2 by the straight line a. The shaded area between the straight line d and the curve 11 represents the complement Use supplied by the contour of the cam 76, which displaces the roller and the follower 80, so turning a square shaft 81 and sector 82 in accordance with the value of the sight angle complement, Usc. Sector 82 thus actuates a pinion 83 and a drive 84 to turn the center 79" of differential D-101 in correspondence with the sight angle complement Use, which is algebraically added to the straight line approximation of the sight angle. Accordingly, the other side 79" of differential D-101 is operated to give the value of the actual sight angle, Us, for the particular advance range, R2, existing at the time.

Side 79" of differential D-101 operates a drive 85 and the side 86' and center 86" of another differential D-100 in accordance with the evaluation of the sight angle, Us, thereby displacing the pivoted contact arm 87 of a follow-up switch to engage one or the other of a pair of fixed contacts 88.

As a result, current will flow from the main 46 of the current supply line by conductors 47 and 89 to the contact arm 87 and the engaged fixed contact 88 and through one of a pair of conductors 90 (shown as a single line) to and through the mutually engaged contact blades of a cut-out switch 91 and therefrom to a sight angle, Us, motor 92. From this motor the current returns by conductors 93, 53, the normally engaged blades 54 and 55 of the multiple-motor cut-out switch, and conductor 56, to the other main 58 of the current supply line. The sight angle, Us, motor 92 will therefore be energized and run.

The Us motor will accordingly operate drives 95 and 96 to actuate a counter 97 to cause it to give a reading of the value of the sight angle, Us. In case of any failure of the Us motor 92, such value may be introduced manually by lifting a spring pressed pin 98 out of the annular groove of a collar 99 into which it is shown in Fig. 1 to be entered, and longitudinally shifting a shaft 99' on which the collar is affixed until a second annular groove is aligned with the pin 98. The manual retracting grip on the pin is then released and the spring pressure on the pin enters the latter into the second annular groove, holding shaft 99 in new axial position. Shaft 99' is so shifted by a manual thrust exerted on a hand crank 100 attached thereto. This shifting operation carries a gear 101 frictionally attached to shaft 99' for rotation therewith into mesh with another gear 102 fast on a shaft 103 that is connected to drive 96 to operate it as the hand crank 100 is turned to manually introduce the value of the sight angle, Us. When the shaft 99 is moved longitudinally in the described manner, its opposite end pushes the longer of the normally engaged blades of cut-out switch 91 out of contact wtih the shorter of these blades, thus opening the circuit through the Us motor 92. Hence, this motor will be deenergized when the sight angle, Us, is introduced manually.

Another drive 104 is connected with drives 95 and 96 so as to be operable by either the Us motor 92 or the Us hand crank 100. Drive 104 operates a further drive 105 which actuates the other side 86" of differential D-100 and the center 86" thereof to return the contact arm 87 to its neutral position, thus opening the circuit through the Us motor 92 when it has run an amount-corresponding to the value of the sight angle, Us, which has been introduced by the side 86 of the differential.

This value of the sight angle, Us, is also transmitted from drive 104 to another drive 106, which operates gearing 107 that has a ratio that multiplies the value of the sight angle, Us, by a constant K4 which is a coefiicient that converts the sight angle, Us, to an approximation T of the time of flight. From the gearing 107 the drive 106 continues to and operates the side 108 of a differ- 'ential D-108 in accordance with the value of the approximation of the time of flight.

To obtain the complement of the time of flight, To, any one of cams 109, 110 and 111 is employed according to the chosen strength of any of a number of powder charges, each of which produces a particular initial velocity of the projectile for a given gun. The time of flight complement cams 109, 110 and 111 are used similarly to the manner in which the sight angle complement camsl 76, 77 and 78 are utilized, and are rigidly mounted on a shaft 112, which also has a worm gear 113 attached thereto and which is in mesh with a worm 114 also operated by the drive 68.

Referring to Fig. 3, the curves 2, f and g represent an pproximation, T', of time of flight plotted against advance range, R2, for the different initial velocities resulting from the use of the different powder charges. Curves, h, i and j represent the actual time of flight, T, plotted against R2. The difference between the ordinates for the approximate time of flight, T, and the actual time of flight, T, represented by the shaded portion, is the time of flight complement, To. To therefore represents the quantity which must be added to the approximation, T, to produce the exact value, 'T.

It will be suflicient to consider merely related curves e and h, and to say that the shaded area between these curves gives the value of the time of flight complement, To, in accordance with which the contour of the time of flight complement cam 109 is shaped. This cam acting on the roller of the follower 115 causes the squared shaft 116 and the sector 117 attached thereto to turn proportionately to the value of the time of flight complement, To, which is transmitted by the pinion 118 and drive 119 to the center 108" of differential D-108. Hence, the time of flight complement, To, is added to the approximation of the time of flight, T, in accordance with which the differential side 108' is actuated whereby the other side 108" of this differential is operable according to the actual time of flight, T.

To adapt the computing mechanisms to either of the other initial velocities, an initial velocity knob 120 is first moved to the right from the position shown in Fig. 1. This effects an axial sliding of a shaft 121 and a cylindrical rack 122 on the opposite end thereof. Cylindrical rack 122, therefore, turns a pinion 123 in mesh with it, a shaft 124 carrying the pinion and another pinion 125 aflixed to the shaft. Pinion 125 consequently displaces a flat rack 126 and a shift bar 127 to which it is attached. Lugs 128 fast on shift bar 127 engage and turn levers 129 secured to the upper ends of the square shafts 81 and 116, so turning these shafts and the followers 80 and 115 carried thereby whereby the followers are angularly displaced to be clear of all of the cams with which the followers are associable.

Shaft 121 in being axially displaced slides through a gear 130 that is journaled in a bifurcated bracket 131 and is provided with a keyway so that the initial velocity knob 120 may be turned, after the followers 810 and 115 have been positioned to clear the cams to which they are related. Knob 120 turns shaft 121, which by virtue of its keyway and a key drives gear 130 and another gear 132 in mesh therewith to operate drives 133, 134 and 135 and flexible driving connections 136 which turn screwshafts 137 that are threaded through the cam followers 80 and 115. These followers are, therefore, moved parallel to the axes of rotation of the sight angle complement and time of flight complement cams into association with such of these cams as are for the particular initial velocity to be conformed to. Knowledge that cam followers have been aligned with the proper cams is had from the reading of an initial velocity dial 138 against a fixed index, this dial being operated from drive 133 by a drive 139.

The initial velocity knob 120, shaft 121 and cylindrical rack 122 are then pushed in the reverse direction, moving the shift bar 127 also in the reverse direction. Shift bear lugs 128 are thus moved out of the way of the levers 129, which are pulled by springs 140 so as to turn reversely the square shafts 81 and 116 thus turning the cam followers cooperatively to engage the perimeters of the cams for the selected initial velocity.

When the shift bar 127 is moved to clear the cam followers of the cams, as described above, another lug 141 is also moved with it allowing the flexed contact blades 54 and 55 to straighten out, under which condition these blades become disengaged. This opens the circuits through the various motors so that they become deenergized during the period when the cam followers are shifted from certain cams to other cams, as will be more fully explained later on.

Also, as the shaft 121 is shifted axially, it is prevented from being subjected to abrupt starting, stopping and other shocks by a hydraulic retarder 142, which is suitably connected by an arm 143 with the shaft 121.

It has been shown that the approximation of the time of flight, T, and the time of flight complement, T0, were combined in dilferential D-108 so that the computed value of the actual time of flight, T, became the output of side 108" of this differential. Side 108" operates a drive 144 and a side 145' and center 145" of a differential D-109, the center turning a pivoted contact arm 146 to engage one or the other of a pair of fixed contacts 147 of a follow-up switch.

Thereupon current will flow from the main 46 of the current supply by conductors 47 and 148 to the contact arm 146, through the engaged fixed contact 147 and one of a pair of conductors 149 (shown as a single line) through normally mutually engaged blades of a motor cut-out switch 150 and therefrom to a time of flight, T, motor 151. Returning from this motor the current goes by conductors 152, 52 and 53, blades 54 and 55 of the multiple-motor cut-out switch, and conductor 56 to the other main 58 of the current supply line. The motor 151 will, therefore, run in accordance with the time of flight, T. In so doing, it operates drives 153, 154 and 155 to operate a counter 156 to give a reading of the time of flight, T. Drive 154 continues to and operates the screw shaft 27 of the multiplier termed the range predictor 26, the driving of which shaft has been earlier referred to.

Furthermore, it has been explained that the center 61' of differential D-12 is operated in correspondence to a range correction, Rv, which is directly proportional to the amount of the initial velocity loss, but with no explanation as to how such correction is obtained. This will now be set forth. A prediction of the range correction for an arbitrary initial velocity loss, designated Rv', is calculated, and this loss may be taken as 200 feet per second initial velocity loss.

When the time of flight motor 151 is running, as explained, it operates drive 153 thereby actuating a portion of drive 154 that extends to and operates another drive 157 which includes gearing 158 that has a ratio which produces a coetncient that constitutes a constant K5. Constant K5 multiplies the time of flight, T, to obtain a straight line approximation of the change of range for the arbitrary initial velocity loss. Continuing from the gearing 158, the drive 157 operates a side 159 of a differential D-102 according to the value of the straight line approximation of the change of range for the arbitrary initial velocity loss.

In Fig. 4 the straight line approximation of the change of range for the unit or arbitrary initial velocity loss is represented by the straight line k, which is plotted against time of flight at appropriate scales. The remainder, Rv'c, of the range correction, Rv', for the arbitrary initial velocity loss is the difference between the straight line approximation denoted by the line k and the actual value indicated by the line I plotted against the two mentioned quantities at the same scale. Therefore, the shaded area between the straight line k and the curve I along the ordinate representing the change of range for the particular value of the time of flight evaluates the remainder, Rv'c, that must be added to the straight line approximation of the range correction, Rv', for the arbitrary initial velocity loss.

To secure the remainder, Rvc, of the range correction Rv', a cam groove 160 is laid out on a rotatable peripherially toothed cam disk 161 in correspondence with the variance of the range correction complement, Rv'c, which varies as a function of the time of flight, T. The drive 157 that is operable proportionately to the time of flight, T, also extends to a pinion 162 which turns the cam disk 161 in accordance with the time of flight, T. As the cam disk so turns it displaces a pin 163 that is entered into the cam groove 160, the pin being a rigid part of a cam follower which further consists of a sector 164 that is pivoted at 165. The toothed arcuate part of the sector 164 operates a pinion 166 and a drive 167 which operates the center 159" of differential D-102 in correspondence with the value of the component Rvc. Thus, the component Rv'c is added to the straight line approximation of the range correction introduced by the differential side 159' whereby the other side 159 is operable proportionately to the range correction for the arbitrary initial velocity loss, Rv'. By the hereinbefore described means, the time of flight is converted to the change of range during the time of flight for an arbitrary initial velocity loss.

Operation of the side 159", as described, actuates a drive 168 and a pinion 169, which angularly displaces a pivoted sector 170 of what may be termed an initial velocity loss corrector 171. Thus, the range correction for the arbitrary initial velocity loss, Rv, is introduced into this corrector where it is multiplied by the actual initial velocity loss, the multiplying mechanism being so designed that the product Rv will bear the same proportion to Rv' that the actual initial velocity loss bears to the arbitrary initial velocity loss. To introduce the actual initial velocity loss a retaining pin 172 urged into a holding position by a spring is raised to remove it from the annular groove in a collar 173 in which it is entered, the collar being fast on an axially shiftable shaft 174. An initial velocity loss knob 175 is then pulled out so axially shifting shaft 174 to mesh a gear 176 thereon with another gear 177. The retaining pin 172 is then released and enters a second groove in collar 173 to hold the gears in mesh. Thereafter the initial velocity loss knob 175 is turned to rotate shaft 174, gears 176 and 177 and a drive 178 which turns a dial 179, causing it to read against a fixed index and it is graduated to show the corresponding initial velocity loss. This value is accordingly transmitted from drive 178 by another drive 180 to a screw shaft 181 that is rotatably mounted on the sector 170 of the initial velocity loss corrector 171. Screw shaft 181 displaces a traveling nut 182 having a rigid pin 183 that extends into a slot in a cross bar 184 of a link 185 which at one end is pivotally connected to a pivoted arm 186. The other end of link 185 is similarly connected to a pivoted output sector 187, which is thus moved in parallelism with the arm 186 with a magnitude dependent upon the combined displacements of input sector 170 and pin 183. These displacements effect the multiplication of the range correction for the arbitrary initial velocity loss, Rv, by the actual initial velocity loss. Hence, the resultant product, as represented by the movement of the output sector 187 is the range correction for the actual initial velocity loss, Rv. It is now apparent that, in addition to the presence of means for converting the time of flight to the change of range during the time of flight for an arbitrary initial velocity loss, there are also means for multiplying such change of range by the proportion between the arbitrary and actual velocity loss.

Displacement of sector 187 in accordance with the range correction for the actual velocity loss, Rv, transmits this quantity by a pinion 188 and a drive 189 to the center 61" of difierential D-12, where it is utilized as hereinbefore set forth to become included in the complete range prediction, RJTWV, and to be subtracted from the quantity Rrwv, forming part of the range prediction, to obtain the output quantity, R'rw, that matches the input quantity, R'rw, whereby the operation of the R'rwv motor 51 is controlled. Drive 189 actuates another drive 190 and a dial 191 so that the latter reads against a fixed index to give a reading of the range correction for the entire initial velocity loss, Rv.

Should the R'rwv and the time of flight motors 51 and 151, respectively, fail for any reason, the mechanism of the former may be operated by a manual control device 192 and the latter by another manual control device 193. Each is in all respects similar to the device 98-102 for manually controlling the sight angle, Us, mechanism and operates in the same way.

It is obvious that various modifications may be made in the construction shown in the drawings and above particularly described within the principle and scope of my invention.

I claim:

1. In mechanism for determining data for use in controlling the aiming of ordnance, means actuated by a range settable member for computing the corresponding time of flight of a projectile for a particular initial velocity, means actuated by the time of flight computing means to determine the corresponding change of range of the projectile due to an arbitrary initial velocity loss from the particular initial velocity, and multiplying means having one input member actuated by the change of range determining means and a second input member actuated in accordance with the actual initial velocity loss for multiplying the said change of range by the proportion between the said arbitrary velocity loss and the actual initial velocity loss.

2. In mechanism for determining data for use in controlling the aiming of ordnance, means positionable in accordance with present range, means for initially positioning said present range means, means settable in accordance with the rate of change of range, integrating means having a rate member positioned by said rate settable means, means actuated by the increments of range obtained from the integrating means to continuously position the present range positionable means, means positionable to represent the time of flight of a projectile, multiplying means actuated by said rate settable means and by the time of flight positionable means to position an output member in accordance with the change of range during the time of flight, means actuated by the time of flight positionable means to position an element in accordance with the corresponding change of range due to an arbitrary initial velocity loss, second multiplying means actuated by the element and in accordance with the proportion between the arbitrary initial velocity loss and an actual initial velocity loss to position an output member in accordance with the change of range for the actual velocity loss, means actuated in accordance with the position of the output of the first mentioned multiplying means and the present range positionable means to position a member in accordance with the advance range, means'for modifying the position of the advance range member in accordance with the position of the output member of the second multiplying means, and means actuated by the advance range member to position the time of flight positionable means.

3. In mechanism for determining data for use in controlling the aiming of ordnance, the combination of means actuated in accordance with the time of flight of a projectile for determining the corresponding range correction due to an arbitrary initial velocity loss, proportional means for converting the said range correction to a range correction for an actual initial velocity loss, mechanism operated in accordance with the time of flight of the projectile for determining a range prediction due to the change of range during the time of flight, means jointly operated by the mechanismand the proportional means for positioning an element in accordance with the range prediction combined with the range correction due to the actual velocity loss, means positionable in accordance with the present range of a target, differential means controlled by the element and the range positionable means to position a member in accordance with the corresponding advance range, and apparatus actuated by said member for determining the sight angle and time of flight corresponding to the advance range.

4. In mechanism for determining data for use in controlling the aiming of ordnance, the combination comprising means actuated in accordance with the time of flight of a projectile for computing a corresponding range correction due to an arbitrary loss of initial velocity, and multiplying means having one input member actuated by said computing means, a second input member actuated in accordance with the actual loss of initial velocity and an output member positioned thereby to represent the range correction corresponding to the actual loss of initial velocity.

5. In mechanism for determinig data for use in controlling the aiming of ordnance, the combination comprising/means positionable in accordance with the range to a target, means actuated thereby for computing a corresponding range correction due to an arbitrary loss of initial velocity, multiplying means having one input member actuated by said computing means, a second input member actuated in accordance with the actual loss of initial velocity and an output member positioned thereby to represent the range correction corresponding to the actual loss of initial velocity, and means actuated by the output member of the multiplying means for 10 modifying the position of the range positionable means.

6. Mechanism for determining data for use in controlling the aiming of ordnance, comprising means settable in accordance with the present range of a target, means for positioning a member in accordance with the correction to be combined with the present range to give the advance range, said positioning means including mechanism for computing the range correction due to relative movement of the target during the time of flight, means for computing the range correction due to the effect of wind on a projectile, and means for computing the range correction due to initial velocity loss, means for determining advance range including differential means actuated in accordance with the positions of the range settable means and the member to position an element to represent the advance range, and means actuated by the element for converting the advance range to the corresponding sight angle.

References Cited in the file of this patent UNITED STATES PATENTS 1,453,104 Gray Apr. 24, 1923 1,811,688 Gray June 23, 1931 1,904,215 Ford Apr. 18, 1933 1,999,368 Myers Apr. 30, 1935

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