Abstract: A vibratory mechanism comprises a motor-driven shaft, a first mass carried by the shaft for rotation therewith, and a variable mass supported for rotation relative to the shaft whereby the angular relationship between the first mass and the variable mass can be selectively adjusted to vary the amplitude of vibration. A drive member is rotatable with the shaft. The variable mass carries a plurality of longitudinally and circumferentially spaced abutment surfaces. The drive member carries a contact face. Engagement between the contact face and the abutment surfaces occurs at different angular relationships between the first mass and the variable mass to vary the amplitude of vibration.

Abstract: A vibratory compacting roller includes a rotatable compacting roll, and a motor driven vibrator. The vibrator includes a shaft, a movable mass rotatable with the shaft and adjustable transversely thereof, and a position regulator for regulating the position of the mass to provide for a variable amplitude of vibration, the amplitude of vibration of the vibrator being lowest when the center of gravity of the mass is nearest the shaft and greatest when the center of gravity of the mass is farthest from the shaft. The position regulator comprises a spring which automatically positions the eccentric mass to the low amplitude position when the shaft is at rest, whereby minimal start-up torque is imposed upon the motor. A releaseable locking mechanism locks the mass in the low-amplitude position.

Abstract: An oscillator producing vibrations at an operating frequency near, but different from, the resonant frequency of a resonant system is coupled to its input and the resonant system is supported a predetermined distance from its free ringing node(s) at position(s) corresponding to the effective node(s) for the operating frequency. The oscillator is controlled to maintain the operating frequency at a predetermined constant value, which keeps the effective nodes at the same position as the load driven by the output of the resonant system varies.

Abstract: An oscillation system, having a vibrator, a resonant bridge and a low resistance, oscillates at desirable frequencies by receiving an excitation signal amplified to a predetermined value by an amplifier. A detection feedback signal containing the resonant frequency of the vibrator is input to a phase shift circuit. The phase shift circuit adjusts the phase of the detection feedback signal and the excitation signal to satisfy the oscillation condition. The output signal from the phase shift circuit is input to a PLL comprised of a phase comparator, a low pass filter, an amplifier and a voltage controlled oscillator. The frequency of the output signal from the PLL follows the resonant frequency of the vibrator and is locked. Its output signal is applied to the amplifier which feeds the oscillation system. An analog multiplier circuit is fed with signals proportional to the current and voltage from the resonant bridge circuit, and outputs the product of these signals.

Abstract: Two eccentric weights of a vibrator are mounted, respectively, on two coaxial shafts, one of which is a hollow shaft mounted on the other shaft. The two shafts can be connected for rotation in unison, and can be separated for relative rotation to alter the angular relationship between the weights. The mechanism is provided to alter the angular relationship between the weights while both shafts continue to rotate. An electric clutch is connected between the driven shaft and the hollow shaft to connect the two coaxial shafts for rotation in unison, and a brake is provided to slow the rotation of the hollow shaft after the clutch is disengaged. Thus, the angular relationship between the eccentric weights, and hence the stroke of the vibrator, can be changed.

Abstract: A clamp means is provided for holding at least one vessel so that the vessel can be agitated by a drive means with the clamping means permitting the vessel to move with the clamping means defining the null point of the movement. The clamp means may provide a rack for resiliently clamping the vessel. Preferably, the clamping means is for resiliently clamping the vessel at a position remote from the bottom thereof. Drive means are provided for imparting motion, such as orbital motion, to the agitating means whereby fluent contents of the vessel are agitated. The apparatus is adapted for the holding and agitating a single or a plurality of vessels, such as a plurality of test tubes. The drive means also is capable of pulsing the orbital motion.

Abstract: An ultrasonic oscillator device which has automatic gain control and which comprises a phase detector for detecting the phase difference between a load voltage and varying quantities indicating an operational condition of the load. The device further comprises a voltage control oscillator adapted to control an oscillating frequency through a direct current voltage corresponding to the phase difference. Further, the ultrasonic oscillator device is combined with a vibrator driven thereby and a small sized motor having a fan to forcedly cool the vibrator. The vibrator and the fan are accommodated in a housing, the size of which is made small, to produce a compact type machine.

Abstract: An oscillatory mechanism, designed particularly for use in a laboratory shaker, includes a member, or a system of members, arranged to perform oscillatory movements, the transmission of power to that member or system, whereby its oscillation is caused or maintained, being by means of fluid pressure, the mechanism comprising means defining one or more chambers each having an inlet connectible to a source of pressurized fluid and an outlet through which, when open, pressurized fluid supplied to each chamber can escape; the respective chamber being expansible under the action of said pressurized fluid when each said outlet is closed; and wherein the motion of the oscillatory member or system in operation cyclically opens and closes each said chamber outlet, the consequent expansion of the respective chamber upon closure of the outlet delivering an impulse to said member or system whereby the oscillation thereof is caused or maintained.

Abstract: A vibrator is prevented from transmitting its vibratory motion to the vibrator holder, such, for example, as a handle, by interconnecting the vibrator and handle with a spring arranged so that the spring serves as a resilient cantilever. Amplitude of vibrations are enhanced without a corresponding increase in the amount of vibration transmitted to the handle by arranging the resilience of the spring and the mass of the vibrator to be resonant at the frequency of vibrations or at a submultiple of those frequencies.

Abstract: This invention relates to a vibrator which for example can be used to vibrate a tray for the purpose of conveying articles or material along the tray or alternatively can be used for vibrating articles or material where there is no requirement for conveyance in a pre-determined direction. A vibrator according to the invention has an actuator assembly which includes an actuator shaft which can rotate relative to said assembly but which is prevented from longitudinal movement relative to the assembly.