Measuring and testing – Speed – velocity – or acceleration – Acceleration determination utilizing inertial element
Reexamination Certificate
1998-09-18
2001-06-19
Kwok, Helen (Department: 2856)
Measuring and testing
Speed, velocity, or acceleration
Acceleration determination utilizing inertial element
Reexamination Certificate
active
06247364
ABSTRACT:
TECHNICAL FIELD
The present invention relates to acceleration transducers and, more particularly, to acceleration transducers for measuring acceleration resulting from impact loading such as can occur in pile driving, impact forming or explosion. The invention is useful in a variety of applications, from slow vibratory applications to impact response applications. An exemplary embodiment of the invention is particularly useful for measuring steel-on-steel impact.
BACKGROUND OF THE INVENTION
Accelerometers for measuring impact behavior must exhibit a high capacity for measuring magnitude and a wide frequency range to capture the full range of signal.
It is desirable that the accelerometer have a first resonant frequency in excess of 20 kilohertz (KHz), thereby allowing it to capture the important components of the stress-wave signal. Consequently, the accelerometer needs to be very rigid and small in size to possess the desired resonant frequency.
There is a strong need in the art for a means for evaluating acceleration resulting from impact loading. In particular, there is a strong need in the art for an accelerometer which is better able to withstand the high impact forces involved in acceleration such as impact forming or blanking and which measures the acceleration and velocity of the tool while still providing a low noise output. This is in contrast to larger strain gage devices and accelerometers used in the prior art which have been found to encounter substantial resonance and other signal degrading conditions making it difficult to measure the acceleration characteristics of a machine under the high impact conditions to which it is exposed.
SUMMARY OF THE INVENTION
According to the present invention, a high strength, high frequency acceleration transducer is used for measuring the acceleration of an impacted machine or structure. The acceleration transducer includes a diaphragm, the diaphragm including one or more strain gages for producing an output signal indicative of the diaphragm flexure. The diaphragm is securely clamped or held over part of its surface, and is free to deflect over other parts, for example, the remainder of its surface—the diaphragm can be clamped or held along its circumference with its middle free to flex, or alternatively the diaphragm can be clamped or held along its center with the outside portion of the diaphragm free to flex. The diaphragm preferably includes a strain concentration mechanism to concentrate the strains locally within the diaphragm towards the strain gages. Due to the small size, profile, shape, and configuration, the acceleration transducer is able to withstand high impact forces and reliably to measure acceleration without being damaged and while avoiding resonance or the like which would degrade the output signal from the strain gages.
In accordance with one aspect of the invention, an acceleration transducer includes a diaphragm responsive to inertially-induced deformations so as to exhibit stress, strain, and deflection; a support attached to a part of the diaphragm; and at least one detector for producing an output in response to the deformations.
In accordance with another aspect, an acceleration transducer includes a diaphragm responsive to inertially-induced deformations so as to exhibit stress, strain, and deflection; a support for holding the diaphragm; and at least one detector for producing an output in response to the strain.
In accordance with yet another aspect, an acceleration transducer includes a housing, a diaphragm disposed within the housing such that the circumference of the diaphragm is rigidly secured or held within the housing and a central portion of the diaphragm is sufficiently free to deflect in response to acceleration of the housing, and at least one strain gage secured to the diaphragm for producing an output representative of the acceleration, the at least one strain gage being located towards an outer radial portion or circumferential portion of the diaphragm, or in any event in the region of measurable strain.
In accordance with still another aspect, an acceleration transducer includes a housing, a diaphragm disposed within the housing such that a central portion of the diaphragm is rigidly secured or held within the housing and the circumference of the diaphragm is sufficiently free to deflect in response to acceleration of the housing, and at least one strain gage secured to the diaphragm for producing an output representative of the acceleration, the at least one strain gage being located towards the central portion of the diaphragm, or in any event in the region of measurable strain.
In accordance with a further aspect, a method of evaluating the integrity of a bar or other object includes the steps of securing a mounting block to the bar to be impacted, securing an acceleration transducer to the mounting block, and monitoring an output of the acceleration transducer in response to impacting the bar.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.
REFERENCES:
patent: 3415116 (1968-12-01), Knechtel
patent: 3492864 (1970-02-01), Kraeling et al.
patent: 3693425 (1972-09-01), Starita et al.
patent: 3695096 (1972-10-01), Kutsay
patent: 3817091 (1974-06-01), Frederick
patent: 3931729 (1976-01-01), Frederick
patent: 3946598 (1976-03-01), Towne et al.
patent: 4052884 (1977-10-01), Milberger et al.
patent: 4064763 (1977-12-01), Srinivasan
patent: 4065971 (1978-01-01), Shimazoe et al.
patent: 4102210 (1978-07-01), Couston et al.
patent: 4332160 (1982-06-01), Baragar et al.
patent: 4348142 (1982-09-01), Figour
patent: 4364259 (1982-12-01), Muranaka et al.
patent: 4399705 (1983-08-01), Weiger et al.
patent: 4400970 (1983-08-01), Ali
patent: 4448083 (1984-05-01), Hayashi
patent: 4483203 (1984-11-01), Capper
patent: 4503351 (1985-03-01), Sonderegger et al.
patent: 4574616 (1986-03-01), Miura et al.
patent: 4586366 (1986-05-01), Milberger
patent: 4671118 (1987-06-01), Hatamura
patent: 4672839 (1987-06-01), Takeuchi et al.
patent: 4704894 (1987-11-01), Inuzuka et al.
patent: 4841783 (1989-06-01), Marshek et al.
patent: 4938065 (1990-07-01), Kobayashi
patent: 4959993 (1990-10-01), Komurasaki
patent: 4984467 (1991-01-01), Haefner
patent: 5125266 (1992-06-01), Ingram et al.
patent: 5150606 (1992-09-01), Komurasaki
patent: 5212421 (1993-05-01), Hatton et al.
patent: 5226325 (1993-07-01), Komurasaki et al.
patent: 5259240 (1993-11-01), Raines et al.
patent: 5295389 (1994-03-01), Nagata et al.
patent: 5295399 (1994-03-01), Grant et al.
patent: 5297430 (1994-03-01), Sonderegger et al.
patent: 5329819 (1994-07-01), Park et al.
patent: 5351542 (1994-10-01), Ichimura et al.
patent: 5377551 (1995-01-01), Vacquer
patent: 5412986 (1995-05-01), Beringhause et al.
patent: 5811910 (1998-09-01), Cameron et al.
patent: 5822173 (1998-10-01), Dague et al.
Kicher Paul T.
Kicher Thomas P.
Kwok Helen
Renner , Otto, Boisselle & Sklar, LLP
Thomas P. Kicher & Co.
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