US2714548A - Velocimeter - Google Patents

Description

Aug. 2, 1955 R. J. PETERsoN VELOCIMETER Filed OC'C. 6, 1952 L-Y" "25m AGENTS States ice VELOCIll/IETER Robert J. Peterson, National City, Calif. Application October 6, 1952, Serial No. 313,213 4 Claims. (Cl. 346-38) The present invention relates generally to speed recording devices and more particularly to a velocimeter for use in recording the speed of projectiles in fiight.

The primary object of this invention is to provide a velocimeter for recording the speed of projectiles and the like and providing a permanent record of said speed.

Another object of this invention is to provide a Velocimeter of the type described which is portable, compact and economical.

Another object of this invention is to provide a velocimeter of the type described having sufiicient means of adjustment to permit its use with many types of projectiles.

Another object of this invention, ancillary to the preceding objects, is to teach the best known mode of implementing the principles of the invention in carrying the invcntion into actual practice.

Another object of this invention is to provide a Velocimeter which is adapted for fabrication from many different materials, so that the choice of material can be according to the dictates of availability and price considerations, the exact sizes and proportions being matters easily determined to suit particular conditions and needs.

Another object of this invention is to provide a velocimeter which is inexpensive and practicable to manufacture.

Finally, it is an object to provide a velocimeter of the aforementioned character which is simple, safe and convenient to operate, and which will give generally eflicient and durable service.

With these and other objects definitely in view, this invention consists in the novel construction, combination and arrangement of elements and portions, as will be hereinafter fully described in the specification, particularly pointed out in the claims, and illustrated in the drawing which forms a material part of this disclosure and wherein similar characters of reference indicate similar or identical elements and portions throughout the specification and throughout the views of the drawing, and in which:

Fig. 1 is a plan view of the Velocimeter;

Fig. 2 is a side elevation view of the velocimeter to which has been added an electrical wiring diagram;

Fig. 3 is an enlarged fragmentary elevation view of the release mechanism of the recorder arms;

Fig. 4 is an enlarged end elevation view of a recording head;

Fig. 5 is an enlarged side elevation view of a recording head;

Fig. 6 is a fragmentary side elevation view of a modified form of the invention; and

Fig. 7 is a sectional view taken on the line 7-7 of Fig. 6.

Referring now to the drawing in detail, the device comprises a base tl on which is mounted a turntable 12 powered by a motor 14, said turntable being in close spaced relationship with the base and in a common plane With said base. At either end of the base 10 are attached brackets 16 and 18, each being longitudinally adjustable on said base and secured by means of bolts 20 passing through slots 22 in said brackets and through the base 10 where they are locked by means of Wing nuts 24. The brackets 16 and 18 each comprises a base plate 26 and a back plate 28 vertically opposed to said base plate, both portions being integrally formed. Arms 30 and 31 are pivotally mounted to the brackets 16 andl 18 by means of hinges 32, said arms being in longitudinal alignment With said bracket and with the base ltl. The arms 38 and 31 are of non-magnetic material and are each provided with a plate 34 of magnetic material. A pair of similar electro- magnets 36 and 37 are suspended from the back plates 28 by means of support brackets 38 adjustably mounted on said back plates by means of bolts 4G slidably engaged in arcuate slots 42, as best illustrated in Figure 3. The arc of each slot 42 has its center of curvature at the aXis of the corresponding hinge 32 and said bolts are loclted by means of wing nuts 44. The,-

arms 3G and are pre-loaded in a downwardly direction by means of tension Springs 45 the tension of which is adjustable by means of nuts 43 threadably engaged with bolts 59 secured to said tension Springs and passing through said arms, the other ends of the tension Springs being secured to the base li) by means of screws 52. Secured to the free ends of the arms 39 and are stylus asseniblies or recording heads 5d, each comprising a hinge block 56 on which is pivotally mounted, by means of a hinge pin 57, a Stylus block S3 containing a stylus 6D. The recording heads are each provided with a spring 62 secured to the hinge block 56 and to the stylus block 58 by means of screws 64, said spring being tensioncd so that a defiection of the stylus block 58 will cause the spring to pull said block into the folded position as shown in dash line at 65 in Fig. 5. The arms St) and 31 are limited in their travel downwardly by means of stops 68 having resilient pads 70.

The bracket 18 carries an assembly of parts similar to those mounted on the bracket 16, but the parts are arranged in reverse in such a manner that the arm 31 is in parallel spaced relationship with the arm 39 on the bracket lo as illustrated in Fig. l. Further, the electromagnet 37 is mounted on a support bracket 72 similar to the support bracket 38, but of suficiently greater length to align the electro-magnet thereon with the plate 34. The recording head 54- on the arrn 31 is also reversed in position in relation to the recording head on the arm 39 so that both of the stylus blocks SS pivot in the same direction for reasons which will be hereinafter explained.

The device is operated by means of a suitable power supply such as a battery 74 having a power lead connected to the motor 1d opened and closed by means of a switch 76, the speed of said motor being Controlled by means of a rheostat 78. The electromagnets 36 are connected in parallel to said battery through two screens 8% and 81, said screens comprising a pluralty of equally spaced parallel wires connected to form single continuous electrical conductors so that the breakage of any portion of a Wire will cause a break in the electrical circuit. The space between each wire should be less than the diameter of the smallest projectile to be used with the device for reasons which Will be obvious. The electro- magnets 36 and 37 are further Controlled by means of a switch 82 situated in the common lead from both magnets.

To operate the device, a disc 84- of paper or other suitable material, is placed on the turntable 12. The brackets 16 and 18 are then longitudinally adjusted so that the axes of both the styli of? fall on a common line extending radially from the axis of the turntable 14. The two screens 89 and 81 are arranged so that a projectile S5 may pass through both screens in its trajectory, the spacing between said screens being a convenient, pre-determined dstance. The electro-magnetic circuit is now completed and the arms 3d are lifted so that the plates 34 are retained by the electromagnets 36 and 37, the Stylus block 58 being positioned vertically and in spaced rela- 3 tionship with the disc 84. The motor 14 is now started, setting the turntable 12 in motion, a pre-determined speed of rotation being attained by adjustment of the rheostat 78. The switch 82 is now opened, de-energizing the electro- magnets 36 and 37, and allowing the arms and 31 to fall so that the styli will strike the disc 84 forming two marks indicated by the numeral 88 in Fig. 1. The rotation of the disc 84 in contact with the styli 60 will tend to pivot the blocks 58 causing them to be pulled into folded or pivoted positions by the Springs 62. The stylus blocks 58 are prevented from striking the disc 84 vwhen in the folded position by means of the stops 68 beneath the arms 30 and 31. It should be ascertained that the marks 88 are on a common radius of the disc 84, this being essential to the accuracy of the following recordings. Should the two marks 88 not be aligned as required, the falling speed of the arms may be adusted by means of the nuts 48 until the striking of the two styli is synchronized. The device now being correctly adjusted, the electro-magnets are energized, the arms raised and the styli returned to Vertical positions. The turntable is set in motion and the projectile is fired. As the projectile 86 passes through the first screen 80, the Circuit to the electro-magnet 36 will be broken causing the Stylus to produce a mark 90 on the disc 84 in the manner previously described, and as the projectile passes through the second screen 81, the electro-magnet 37 will be de-energized and the second stylus will produce a mark 92 on the disc 84. The two marks 90 and 92 will be spaced according to the angle of rotation as illustrated in Fig. l, and the speed of the projectile may be calculated from said angle of rotation, usually being the measured angle subtended by radii extending through the marks 90 and 92, since only a partial rotation is ordinarily allowed, and two predetermined factors, the known speed of rotation of said disc and the known distance between the two screens. As a very simple example, let us assume that the screens and 81 are 150 feet apart, the speed of rotation of the disc 84 is one revolution per second and the angle of rotation between the two marks and 92 is 36 degrees. Then the time taken by the projectile to pass between the screens was 3%60 or 1A0 of a revolution of the disc. At one revolution per second this would require 1/10 second, so the projectile travelled 160 feet in 1A0 second which would be l50 l0 or 1500 feet per second.

A modification of the device utilizing the same principles as that already described is illustrated in Figs. 6 and 7 in which a bracket 94 carrying a sub-bracket 96 is secured to the base 10. The sub-bracket 96 supports two solenoids 98 positioned so that their axes are on a common radial line from the axis of the turntable 12, said solenoids being electrically connected in a manner similar to the electro- magnets 36 and 37. In each solenoid is slidably fitted a plunger 100 comprising a nonmagnetic stem 102 having a fiange 104 and a stud 106. A hinge block 108 is threadedly engaged in fixed relationship with the stem 102 by means of a threaded portion 110 said hinge block being of magnetizable material. A stylus block 112 having a stylus 114 is pivotally attached to the hinge block 108 by means of a hinge pin 116, said stylus block being actuated by means of a spring 118 retained by screws 119 in a manner similar to that previously described. The plungers 100 are pre-loaded by means of Springs 120 fitted over the studs 106 their travel being limited by the fianges 104 as illustrated in Fig. 7. The tension of the springs is adjusted by means of screws 122 threadedly engaged with the bracket 94, said screws each having a stud 124 and engaging with Washers 126 against said spring. When the solenoids are energized the plungers will be forced down causing the styli to strike the disc 84, the sequence of action and the results being similar to those already described.

The operation of this invention will be clearly comprehended from a consideration of the foregoing description of the mechanical details thereof, taken in connection with the drawing and the above recited objects. It will be obvious that all said objects are amply achieved by this invention.

Further description would appear to be unnecessary.

it is understood that minor Variation from the form of the invention disclosed herein may be made without departure from the spirit and scope of the invention, and that the specification and drawing are to be considered as merely illustrative rather than limiting.

1 claim:

i. A velocimeter for use with projectile-interrupted electric Circuit means spaced apart and individually connected with an electromagnetic means and with a source of energy, having a base, a powered turntable mounted on said base, a recording disc on said turntable, a pair of stylus assemblies, supporting means holding said stylus assemblies above said turntable and spaced along a radius of the turntable, electromagnetic means retaining said Stylus assemblies retracted from said turntable when said ciectromagnetic means are energized, said stylus assemblies having means for biasing the same toward said turntable, each of said stylus assemblies comprising a hinge block, a stylus block pivotally mounted on the hinge block to remain normally in operative position and to move in one direction into inoperative position, a Stylus on said stylus block, spring means to pivot said stylus block on said hinge block when said stylus strikes said turntable in motion, whereby the stylus is allowed to move with said turntable and is withdrawn therefrom after such striking without damage to the turntable and any recording disc thereon, both of said stylus blocks being pivotally removable in the same direction.

2. Apparatus according to claim 1 and wherein said spring means is a coiled spring terminally secured under tension to and between said blocks.

3. A velocimeter according to claim l wherein said supporting means comprises a pair of arms pivoted on said base, said arms being independently actuatable to move said stylus assemblies into operative positions.

4. A velocimeter for projectiles for use with projectile-interrupted electric circuit means spaced apart and individually connected with an electromagnetic means and with a source of energy, said velocimeter comprising a base, a powered turntable operably mounted on said base, arms pivoted on said base and having corresponding portions extending over said turntable, a recording disc on said turntable, electromagnetic means retaining said arms in positions with said portions retracted from said disc when said electromagnetic means are energized, said arms having means for biasing the same to move so that said portions approach said disc when said electromagnetic means are de-energized, and a Stylus assembly operably mounted on each of said portions to strike said disc, each of said Stylus assemblies comprising a hinge block, a stylus block pivotally mounted on the hinge block to remain normally in operative position and to move in one direction into inoperative position, a stylus on said Stylus block, spring means to pivot said stylus block on said hinge block when said stylus strikes said turntable in motion, whereby the stylus is allowed to move with said turntable and is withdrawn therefrom after such striking without damage to the turntable and any recording disc thereon, both of said stylus blocks being pivotally movable in the same direction.

References Cited in the file of this patent UNITED STATES PATENTS

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