Calculating damping for belts

#Workers making or using flexible web means (e.g., belts used to transmit motion from one shaft to another) have long been concerned about the complications now typically associated with determining damping characteristics (e.g., damping coefficient) of such a web. Typically, this may involve "trial-and-error" testing of the actual belt in the actual mechanism; or it may require a specific sample size, or it may require that the belt be permanently altered in some way; or "over-stressed" in actual use-environment.

#This invention addresses such concerns, and teaches a technique and apparatus for determining such damping coefficients:

#without need of trial-error testing of an actual belt length in an actual use-environment, or any associated belt altering or overstressing;

#The foregoing and other features and advantages of the present invention will be appreciated by workers as they become better understood by reference to the following detailed description of the present preferred embodiments, these being considered in conjunction with the accompanying drawings, wherein like reference symbols denote like elements:

#FIG. 1 is a very schematic, idealized showing of a preferred belt tensioning/shaking arrangement;

#FIG. 2 illustrates a preferred measurement array for measuring belt damping for an arrangement like that of FIG. 1; and

#FIG. 1 shows a frame F which is relatively rigid when compared to the belt B being tested, being secured to a shaker table (not shown) adapted to experience a known sinusoidal motion. Pulleys P-1, P-2 are affixed on the frame F. A length of belt B (endless-loop or not; also includes any belt-like, web material) is stretched over, and between, the pulleys P-1, P-2. The distance L between pulleys is adjustable so that a desired tension may be produced in belt length B. Such tensioning is well known to those practiced in the related arts. Belt B is clamped to the pulleys over a narrow arc, away from the points where the belt segments are tangent to the pulleys. This prevents gross relative motion between the belt and the pulleys.

#A weight 10 of known mass (test mass m), is clamped to belt B at some known distance L1 from the center of one pulley P-2. Various known means of clamping may be used, such as a common C-clamp as known in the art. This clamp, with any needed transducer attached to it, should have its center of gravity near the (width, and thickness) axis of belt B.

#Motion-Detect means MD (e.g., see accelerometer 2a, FIG. 2) is used for measuring the vertical motion-amplitude of mass m, either relative to the shaker table or relative to the same reference as the shaker motion. This may be accomplished by any one of many well known expedients such as: an accelerometer or like transducer (with indicator also used, if desired--see FIG. 2), or a recording pen, or a light beam reflected off the mass m onto a scale, or an electromagnetic voltage generator, etc. For illustration purposes, accelerometers will be preferred here to measure motions of both the mass m and the shaker table. Such accelerometers are well known to artisans familiar with motion transducers. For illustration purposes, these accelerometers are assumed to measure acceleration relative to the earth. Piezo-electric accelerometers are well known examples and preferred. Or, one may equivalently measure velocity or displacement, instead of acceleration, as artisans understand.