The Singer Company

Alliedsignal Inc.

Lucas Schaevitz Inc.

Crystal Gage Inc.

United States of America As Represented by the Secretary of the Air Force

William C Albert

Bart J Zoltan

Herbert T Califano

Robert M Hohenstein

A monolithic resonator for a vibrating beam device, either an accelerometer or a pressure transducer, includes an outer structure and an inner structure. The outer structure includes a mounting structure, a proof mass or pressure transfer structure and a plurality of flexure beams parallel for the accelerometer and perpendicular for the pressure transducer, extending between the mounting and either proof mass or pressure transfer structure. The inner structure is connected to the outer structure and contains isolator masses, isolator beams and a vibrating beam. The outer structure has a thickness greater than the intermediate thickness of the isolator masses which is in turn thicker than the inner structure thickness of the isolator beams and vibrating beam. The intermediate thickness is independently selected to achieve the ideal mass requirements of the vibration isolation mechanism.

Monolithic resonator for vibrating beam force sensors

A vibrating beam accelerometer contains an inner structure having a vibrating beam extending between a pair of isolator masses which are connected via isolator beams to a pair of structures, an outer structure having flexure beams extending between a mount structure and a proof mass structure and a peripheral seal structure surrounding said inner structure and said outer structure. Seal plates containing a ring of glass frit material sandwich the above assembly. An electrode pattern termination extends from the above assembly, through the ring of glass frit material, to electronic circuitry containing an oscillator.

Vibrating beam accelerometer

A monolithic resonator structure for a vibrating beam force sensor, comprising an accelerometer and pressure transducer, is provided which comprises an outer structure including a mounting structure, a force transfer structure, a plurality of flexure beams extending between the mounting and force transfer structures; and an inner structure including a vibrating beam extending between the mounting structure and the force transfer structure. The monolithic resonator is non-planar in that the outer structure has a thickness greater than said inner structure.

A monolithic resonator for a vibrating beam accelerometer is provided which comprises an outer structure including a mounting structure, a proof mass structure, a plurality of flexure beams extending between the mounting and proof mass structures; and an inner structure including first and second isolator masses, first and second isolator beams connected to one portion of the isolator masses, respectively, and a vibrating beam extending between other portions of the isolator masses. The monolithic resonator is non-planar in that the outer structure has a thickness greater than said inner structure.

Monolithic resonator for a vibrating beam accelerometer

Apparatus for measuring force, useful in a weighing scale for example, includes a parallelogram-like load cell structure that deflects in response to application of the force to be measured, and a pair of force-sensitive crystal resonators, attached to cantilever sensor beams forming part of the structure for sensing the deflection of the load cell structure. The two resonators are attached to the sensor beams such as to be placed in tension and compression, respectively, upon deflection of the structure and thereby cause their vibration frequency to increase and decrease, respectively, with increases in applied force. The difference between the two frequencies, which varies substantially linearly with changes in applied force and is inherently digital in nature, is used as a measure of the force applied to the load cell structure.

Load cell having digital output

In order to implement a vibrating beam accelerometer, preferably in a dual beam configuration, a monolithic piezoelectric structure which includes at least a first mounting surface, a second mounting surface spaced therefrom and between the mounting surfaces and coupled thereto a vibrating beam, is provided. The two mounting surfaces are connected to each other by flexures so that relative movement between them is possible. This structure results in a closed path from mounting surface to vibrating beam to mounting surface avoiding problems present in prior art devices in which there were joints at three different points within the closed path.

Monolythic resonator vibrating beam accelerometer

A vibrating beam resonator is formed with a unitary isolator mass at each end of the vibratory beam. Isolator springs connected to the unitary masses are joined to mounts. Forces applied to the mounts cause the vibrating beam frequency to vary to enable precise force measurements. With this arrangement, fewer cutting operations are required to produce the vibrating beam resonator than were necessary with known resonators. In a preferred embodiment, a side of the vibratory beam is formed by an edge of the crystal blank from which the resonator is cut to further reduce cutting time. This also permits cuts to be made from only one side of the blank.

Force sensing vibrating beam resonator

A single beam force transducer is provided with integrally affixed isolation springs which are axially compliant and unbalanced in their spring rates so as to induce beam bending due to applied tension and compression. The amount of bending introduced due to applied tension will be of a precise magnitude so as to substantially cancel undesirable non-linear vibration effects.

Linearizing mechanism for a vibrating beam force transducer

A single beam force transducer has a beam characterized by a thickened central portion and tapered outward portions. The support members of the transducer are thickened and are thus stiffer while the isolator masses are shortened. These critical configuration changes raise the undesirable 'tuning fork' resonant frequency of the beam supporting structure far above that of the beam and ensures that the isolating structure behaves as a rigid body.

Non-prismal beam resonator

An improved integrating accelerometer having a plurality of proof masses adapted to move relative to a casing in response to accelerations of the casing, a temperature compensated damping mechanism, and fluid resistors for extending the temperature operating range and for calibrating.

Adjustable fluid resistors for use in an integrating accelerometer

A gyro includes a rotatable hub with a flexing member centrally supporting a rotor. The rotor is further supported by a pair of piezoelectric force transducers angularly separated by 90 degrees. The rotor turns with the hub. Oscillators drive the transducers and, as the gyro undergoes angular displacement, the oscillators 'follow' the instant natural frequency of the transducers. FM signals are generated which may be resolved into two digital signals indicative of angular rate about the gyro case X and Y axes.

Resonator restrained gyro

A vibrating beam accelerometer is provided which includes a quartz vibrating beam resonator as aa force transducer, and which also includes resiliently biased relief arms which release the quartz beam should the acceleration forces become excessive. The relief arms serve to protect the beam against overload forces, and to permit the proof mass of the accelerometer to be sufficiently high as to enable the accelerometer to measure accelerations in a relatively wide range as compared with the range capabilities of prior art vibrating beam accelerometers.

There is disclosed an apparatus for monitoring acceleration of a body which utilizes liquid flow technology thus avoiding the need for electrical power. The apparatus includes steel balls of predetermined mass (hereafter 'proof masses') disposed in annular cavities of a casing, the cavities containing a damping fluid. The cavities are grouped in pairs, each pair aligned with a principal axis of the body. The pairing allows for detection of acceleration in opposite directions along the respective axis. Movement of the proof masses in these respective cavities is proportional to the time integral of acceleration along the corresponding axis. This movement develops a force which opens a check valve arrangement allowing for displacement of the fluid through a temperature compensating mechanism to a first piston-chamber arrangement which registers the total movement of all such proof masses. Fluid is returned to the cavity by a second path connected between the cavity and the chamber. Disposed in a second chamber is another piston like arrangement. The piston or float member is in a neutrally buoyant condition. When the apparatus is made operable, the float member is urged from an initial position to a second one which takes a prespecified amount of time. If during this time, the total movement of the proof masses (as combined by the movement of the piston in the first chamber) reflects a time integral of acceleration above a predetermined amount, the first piston interrupts the movement of the float member. Thus the apparatus is suitable for registering when a 'zero' G condition has existed for a prespecified period of time, in that, under such a condition, the piston in the first chamber will not have moved the distance required to interrupt the movement of the float member.

Apparatus for monitoring acceleration

A damping mechanism suitable for use with a vibrating beam accelerometer comprising a piezoelectric block mounted between the vibrating beam force transducer and the pendulum of the instrument. The proof mass, or pendulum, is mounted for pendulous motion about a pair of hinge means. Vibration of the instrument causes opposite charges to appear on electrodes which are on two opposite faces of the block. These charged electrodes are connected to each other by a resistor and so a current will flow through the resistance to neutralize the charge. The resistor will then dissipate the vibration energy as heat. This energy dissipation is effectively damping.

Piezoelectric damping mechanism

In an accelerometer in which a proof mass is disposed in a damping fluid and acts against said fluid through a flow path controlled by the groove length of a helix disposed on a bellows, a low resistance flow path is provided connecting the areas above and below the helix to prevent movement of the proof mass due to fluid displacement caused by rapid temperature changes.

Growing community of inventors

Boonton, NJ, United States of America

William C Albert