US 3515388 A
Description (OCR text may contain errors)
June 2; A. A. ZACYH'MEIEVR 35315388 TARGET RAISING MECHANISM Filed May a, 1968 :5 Sheets-She et 1 INVENTOR.
June 2, 1970 iAHMEIER 3,515,388
TARGET RAISING MECHANISM Filed May 8, 1968 3 Sheets-Sheet 2 Aajas/ 4. Zdcfime/r IN VENTOR.
Z-hk A'meq June 2, 1970 ZACHMEIER' 3,515,388
TARGET RAISING MECHANISM v I Filed May 8, 1968 3 Sheets$heet 3 Aayaaf 4. Zmhzre/er I N VEN TOR.
United States Patent 3,515,388 TARGET RAISING MECHANISM August A. Zachmeier, Joppa, Md., assignor, by mesne assignments, to the United States of America Filed May 8, 1968, Ser. No. 727,539 Int. Cl. F137j 7/00 U.S. CI. 273105.6 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION In the field of target raising mechanisms for silhouette targets simultating an enemy, previous methods included mechanisms which raised and lowered the target with the target in fixed attitude in relation to the drive axis for movement. This method has been found unsatisfactory because of power requirements to raise the target with the required time frame (usually one second) under variable wind conditions imposing surface pressure loading of the target. Thus, for example, the target might at one time be raised broadside into the wind and another time an edge of the target might be directed into the wind. Variable wind loading also has a direct variable effect on target motion. In addition to the above, the moment of inertia of target and counterweight in present targets has been an appreciable factor in creating added power requirement. Also in the prior art type mechanisms the target is driven from lowered to raised position through an arc of 90 and reversal of the drive axis has been required for each raise and lower movement, thereby requiring additional power for additional inertial forces.
In contrast to the above, mechanism incorporating the subject invention reduces power requirements by providing an omni-planal motion to the target which is continuously variable with respect to wind direction. At the same time power requirements are further reduced by minimizing the inertial forces required to rotate the target and counterweight about the drive axis, by eliminating the need to reverse the drive axis and by providing 180 rotation of the drive axis between each raised and lowered target position. Inherent also in subject invention mechanism is a reduction in the overall silhouette or height of the down position of the target and associated mechanism.
SUMMARY OF THE INVENTION The invention comprises a target raising mechanism in which a target and counterweight are fixed to a drive shaft in an attitude of 45 to the drive shaft axis and the drive shaft is mounted in a support housing for rotation on an axis 45 to the ground when the housing is ground supported such that in operation the target is rotated simultaneously about the drive axes and the centroidal axes of the target upon rotation of the drive shaft, together with indexing means and clutch means rotating the drive shaft in increments of 180 rotation.
3,515,388 Patented June 2, 1970 "ice BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a target raising mechanism showing rotation of the target as it is raised.
FIG. 2 is a side elevation partially in section showing details of the drive and drive supporting housing of the mechanism of FIG. 1,
FIG. 3 is a side elevational view showing the mechanism of FIG. 1 and FIG. 2 with a modified form of mounting the target and counterweight to the drive shaft, and also incorporating theinvention, and
FIG. 4 is a single line side elevation diagrammatic representation of the target and drive axes relationship of the mechanism of FIG. 1.
DESCRIPTION THE PREFERRED EMBODIMENT Referring to the drawings and initially to FIGS. 1 and 2, the numeral 10 in FIG. 1 indicates generally a target raising mechanismincorporating the invention. Mechanism 10 includes a positioning arm 12 having opposite ends to which are mounted a target 14 and counterweight 16. Arm 12 is connected, as will be described hereinafter, to a drive shaft 18 mounted at a 45 angle to ground level in a ground supported housing 20 which is shielded from projectiles by a U-shaped shield 22.
Referring to FIG. 2, the shaft 18 is journaled in a shaft housing 24 welded or otherwise suitably fixed to a motor plate 26 forming part of the housing 20. The shaft 18 is rotated by a drive motor 28 and drive belt 30 through a clutch 32, the rotation being limited to 180 increments by suitable mechanism including an indexing cam 34 which is connected by suitable actuator means 35 to engage and release the clutch 32. Suitable bearing means, for example bearing 36, and shaft seal means as indicated at seal 38 are provided for the shaft 18.
To provide for rotation of the target 14 and counterweight 16 about the centroidal axis of each as well as about the axis of drive shaft 18 while providing a 45 angular relationship of the drive shaft axis to said centroidal axes, a collet 40 is keyed as at 50 to the shaft 18 and the positioning arm 12 is shaped as indicated in FIG. 2 to attach the counterweight 16 to one end thereof through fastenings 52 and the target 14 to the opposite end thereof through a curved target apron fastener 54. Suitable fastenings 56 are employed to secure the central portion of the arm 12 to the collet 40.
In a modified form of the invention as shown in FIG. 3, a straight positioning arm 58 is employed and a collet 60 having a 45 angular face 60a is employed to provide the necessary 45 relationship of centroidal and drive axes mentioned above.
In each of the arrangements described above, rotation of the drive shaft 18 from an indexed down target position to a raised target position rotates the target 14 in an omni-planal fashion as indicated in FIG. 1 and shown diagrammatically in FIG. 4. FIG. 4 indicates the lowered and raise positions of the target 14 in relation to a vertical centerline shown at 62 and the angular relationship of the target centroidal axis 64 and counterweight centroidal axis 66 in reference to the drive shaft 14 axis. The target rotation effected continuously varies the attitude of the target in relation to a prevailing wind direction and effects a elevation of the target with rotation of the drive shaft 18, each function contributing to a reduction in required power capacity of the drive motor 28. At the same time the 45 relationship maintained between the centroidal axes of the target and counterweight to the drive axis of the drive shaft 18 reduces inertial load, thereby reducing power requirements and also contributes to a minimum height of target raising mechanism silhouette. In addition, since the drive shaft 18 may be rotated in the same direction from both raising and lowering of the target, the drive motor 28 may be continuously run and the kinetic energy of the rotating motor is applied through the clutch 32 in moving the target 14. Inertia of the motor itself is eliminated since the motor need not be reversed.
It will be understood that various changes in the details, materials, and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.
1. An improved target raising mechanism comprising,
(a) a drive shaft having a drive axis,
(b) housing means for supporting said shaft with its drive axis at an angle of 45 to the ground when said housing means is ground supported,
(c) drive means for rotating said shaft in 180 increments,
(d) a target,
(e) a counterweight means for counterweighting the mass of said target,
(f) mounting means shaped and disposed to hold said target and said counterweight means with respective centroidal axes thereof at a 45 angle to said drive axis to rotate said target and counterweight means about said drive axis and also about said respective centroidal axes responsive to rotation of said drive shaft.
2. A target raising mechanism according to claim 1,
(a) said drive means including a drive motor, a clutch and an indexing cam and clutch actuator means for controllably rotating said shaft in 180 increments to raise and lower the said target.
3. A target raising mechanism according to claim 1,
(a) said mounting means including a positioning arm having means at opposite ends for securing said target and said counterweight to said arm and an adapter having an inclined face for connecting said arm to said shaft at a angle.
4. A target raising mechanism according to claim 3,
(a) said drive means including a drive motor, a clutch and an indexing cam and clutch actuator means for controllably rotating said shaft in increments to raise and lower said target.
5. A target raising mechanism according to claim 1,
(a) said mounting means including a positioning arm having means at opposite ends for securing said target and said counterweight to said arm and a central portion for securing said arm to said shaft, the ends of said arm being bent to position said centroidal axes of said target and counterweight at 45 to said drive axis.
6. A target raising mechanism according to claim 3,
(a) said drive means including a drive motor, a clutch and an indexing cam and clutch actuator means for controllably rotating said shaft in 180 increments to raise and lower said target.
References Cited UNITED STATES PATENTS 2,232,743 2/1941 Swenson 273-1052 3,034,788 5/1962 Cauble 273----105.6
FOREIGN PATENTS 271,866 3/1914 Germany.
35 ANTON O. OECHSLE, Primary Examiner M. R. PAGE, Assistant Examiner