US4010679A — Piezoelectric transducer sensor for use in a press

Claim 1

Independent Claim 284 words

In a machine having two work members movable with respect to each other and subject to repetitive loading forces for transmission to a work piece between said members, at least one force carrying member carrying and transmitting said loading force to one of said work members, and an electrically responsive strain sensing device positioned on said force carrying member, the improvement in combination therewith wherein said sensing device is a piezoelectric transducer, said piezoelectric transducer comprising a piezoelectric element, a first terminal block positioned against one face of said element, a second terminal block positioned against the opposite side of said element, and means for shielding said piezoelectric element from electric and magnetic noise, a mounting means attached to and extending from the force carrying member, said mounting means comprising a first and a second bracket spaced from each other, one end of each bracket being attached to said force carrying member, the other ends of said brackets having contact means for engagement with said terminal blocks, at least one of said contact means being electrically nonconductive, said piezoelectric transducer being positioned and clamped between the said other ends of the brackets with the contact means of said first bracket engaging said first terminal block and the contact means of said second bracket engaging said second terminal block so that the clamping force of the brackets is substantially parallel to and aligned with a line normal to the interfaces between said element and terminal blocks, and an energized electronic circuit electrically connected to the terminal blocks which circuit is predeterminedly activated by the output signal of the piezoelectric transducers when stressed during a work cycle of the machine to activate a machine monitoring means.

Claim 2

Dependent Claim 284 words

In a machine having two work members movable with respect to each other and subject to repetitive loading forces for transmission to a work piece between said members, at least one force carrying member carrying and transmitting said loading force to one of said work members, and an electrically responsive strain sensing device positioned on said force carrying member, the improvement in combination therewith wherein said sensing device is a piezoelectric transducer, said piezoelectric transducer comprising a piezoelectric element, a first terminal block positioned against one face of said element, a second terminal block positioned against the opposite side of said element, and means for shielding said piezoelectric element from electric and magnetic noise, a mounting means attached to and extending from the force carrying member, said mounting means comprising a first and a second bracket spaced from each other, one end of each bracket being attached to said force carrying member, the other ends of said brackets having contact means for engagement with said terminal blocks, at least one of said contact means being electrically nonconductive, said piezoelectric transducer being positioned and clamped between the said other ends of the brackets with the contact means of said first bracket engaging said first terminal block and the contact means of said second bracket engaging said second terminal block so that the clamping force of the brackets is substantially parallel to and aligned with a line normal to the interfaces between said element and terminal blocks, and an energized electronic circuit electrically connected to the terminal blocks which circuit is predeterminedly activated by the output signal of the piezoelectric transducers when stressed during a work cycle of the machine to activate a machine monitoring means.

Claim 3

Dependent Claim 20 words

In a machine in accordance with claim 1 wherein said shielding means comprises a metal sheath surrounding said piezoelectric element.

Claim 4

Dependent Claim 64 words

In a machine in accordance with claim 1 wherein said element is a ceramic crystal and the said other end of said first bracket contains an adjustably movable means which can be adjustably moved to fixed positions away from and toward the terminal blocks to position the piezoelectric transducer in the mounting means and adjustably set the clamping force upon the mounted piezoelectric transducer.

Claim 5

Dependent Claim 32 words

In a machine in accordance with claim 3 wherein the ends of said brackets constitute ball and socket joints wherein the balls thereof are electrically nonconductive and engage said respective terminal blocks.

Claim 6

Dependent Claim 57 words

In a machine in accordance with claim 4 wherein the socket of one of said brackets is adjustably movable with respect to the bracket for adjustable movement to fixed positions away from and toward the terminal blocks to position the piezoelectric transducer in the mounting means and adjustably set the clamping force upon the mounted piezoelectric transducer.

Claim 7

Dependent Claim 26 words

In a machine in accordance with claim 5 wherein said socket is in the end of a set screw screwed into the end of the bracket.

Claim 8

Dependent Claim 92 words

In a machine in accordance with claim 1 wherein said electronic circuit comprises a voltage actuated controller means, a relay means connected in series with the voltage actuated means and actuated by current flowing therethrough, a source of D.C. power for said circuit, a D.C. voltage source providing a voltage impressed on said voltage actuated controller means to prevent current through said circuit at the compressed voltage, and electrical leads connecting and voltage actuated means with the terminal blocks of said piezoelectric transducer to transmit to said means said voltage output signal.

Claim 9

Dependent Claim 43 words

In a machine in accordance with claim 7, wherein said electronic circuit includes a circuit breaker in series with said voltage actuated means and said relay means for breaking said circuit after the flow of current therethrough after actuation of said relay means.

Claim 10

Dependent Claim 100 words

In a machine in accordance with claim 1 wherein said element is a ceramic crystal and said electronic circuit comprises an electronic vacuum tube having a plate, cathode and at least one grid, a relay switch in series with the plate circuit actuated by current flowing through said circuit, a source of D.C. power for said circuit and a D.C. voltage source providing a bias voltage for said grid, said piezoelectric transducer being connected to said grid across a R-C circuit to convert the output signal of high peak, short duration voltage to a signal of low, longer duration voltage.

Claim 11

Dependent Claim 115 words

In a machine in accordance with claim 9 wherein said relay switch controls a monitoring means to stop the machine when overloaded and to count the number of times the machine is stopped and wherein said bias voltage is selected to be substantially equal to the peak output voltage of the piezoelectric transducer at a predetermined maximum loading during a work cycle, whereupon overloading of the machine the piezoelectric transducer responds to produce a conditioned output voltage signal greater than said bias signal and current flows in the circuit to actuate the relay switch, said switch thereby activating the control to stop the machine and to count the number of times the machine is overloaded.

Claim 12

Dependent Claim 91 words

In a machine in accordance with claim 9 wherein said relay switch controls a monitoring means comprising a production counter and wherein said bias voltage is a delected minimum value less than the peak output voltage of the piezoelectric transducer at a predetermined loading necessary for the machine to do work, whereupon when the machine does its intended work the piezoelectric transducer responds to produce an output voltage greater than said bias voltage and current flows in the circuit to activate the relay switch, said switch thereby activating said production counter.

Claim 13

Dependent Claim 76 words

In a machine in accordance with claim 1 wherein said means for shielding said piezoelectric element includes a metallic sheath surrounding said piezoelectric element and terminal blocks, and the said other end of said first bracket contains an adjustably movable means which can be adjustably moved to fixed positions away from and toward the terminal blocks to position the piezoelectric transducer in the mounting means and adjustably set the clamping force upon the mounted piezoelectric transducer.

Claim 14

Dependent Claim 67 words

In a machine in accordance with claim 1 wherein said first and second brackets each have one threaded end, said force carrying member having a pair of internally threaded apertures, and said threaded bracket ends each are screwed into one of said force carrying member apertures for secure engagement with said member, whereby said brackets rigidly support said transducer in close relation to said force carrying member.

Claim 15

Dependent Claim 196 words

In a machine having two work members movable with respect to each other and subject to repetitive loading forces for transmission to a work piece between said members, at least one force carrying member carrying and transmitting said loading force to one of said work members, and an electrically responsive strain sensing device positioned on said force carrying member, the improvement in combination therewith wherein said sensing device is a piezoelectric transducer, said piezoelectric transducer comprising a piezoelectric element, a first terminal block positioned against one face of said element and a second terminal block positioned against the opposite side of said element, means surrounding said piezoelectric element for shielding said element from electric and magnetic noise, a mounting means attached to and extending from the force carrying member, said mounting means engaging said terminal blocks to create compressive forces in said piezoelectric element and terminal blocks substantially parallel to and aligned with a line normal to the interfaces between said element and terminal blocks, and a monitoring means electrically connected to said terminal blocks and being predeterminedly activated by the output signal of the piezoelectric transducer when stressed during a work cycle of the machine.

Claim 16

Dependent Claim 196 words

In a machine having two work members movable with respect to each other and subject to repetitive loading forces for transmission to a work piece between said members, at least one force carrying member carrying and transmitting said loading force to one of said work members, and an electrically responsive strain sensing device positioned on said force carrying member, the improvement in combination therewith wherein said sensing device is a piezoelectric transducer, said piezoelectric transducer comprising a piezoelectric element, a first terminal block positioned against one face of said element and a second terminal block positioned against the opposite side of said element, means surrounding said piezoelectric element for shielding said element from electric and magnetic noise, a mounting means attached to and extending from the force carrying member, said mounting means engaging said terminal blocks to create compressive forces in said piezoelectric element and terminal blocks substantially parallel to and aligned with a line normal to the interfaces between said element and terminal blocks, and a monitoring means electrically connected to said terminal blocks and being predeterminedly activated by the output signal of the piezoelectric transducer when stressed during a work cycle of the machine.

Claim 17

Dependent Claim 46 words

In a machine in accordance with claim 14 wherein said piezoelectric element is a ceramic crystal, and said shielding means is a metallic sheath surrounding said crystal and terminal blocks, and an insulating plastic layer is interposed between said metallic sheath and said crystal and terminals.

Claim 18

Dependent Claim 101 words

In a machine in accordance with claim 15 wherein said monitoring means is connected to said terminal blocks by electronic circuitry including a voltage actuated controller means, a relay means connected in series with the voltage actuated means and actuated by current flowing therethrough, a source of D.C. power for said circuit, a D.C. voltage source providing a voltage impressed on said voltage actuated controller means to prevent current through said circuit at the compressed voltage, and electrical leads connecting said voltage actuated means with the terminal blocks of said piezoelectric transducer to transmit to said means said voltage output signal.

Claim 19

Dependent Claim 56 words

In a machine in accordance with claim 14 wherein said mounting means comprises a pair of spaced brackets each having one threaded end, said force carrying member having a pair of internally threaded apertures, and said threaded bracket ends each are screwed into one of said force carrying member apertures for secure engagement with said member.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1980-03-07	1980-09-06	1981-03-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1984-03-07	1984-09-06	1985-03-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1988-03-07	1988-09-06	1989-03-08	$7700.00	Window Closed / Lapsed

Piezoelectric transducer sensor for use in a press

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