Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
233 words
In a motor operated valve, having a motor operator including motor drive means, a stem nut coupled to the motor drive means for rotation about an axis and stem nut lock means coupled to the motor drive means for preventing axial movement of the stem nut, the valve including a valve gate, a valve seat and a valve stem coupled to the valve gate, the valve stem threadingly engaging the stem nut for axial movement in a first direction upon rotation of the stem nut in a first direction to move the valve gate toward and into engagement with the valve seat and for axial movement in a second direction upon rotation of the stem nut in a second direction to move the valve gate out of engagement with and away from the valve seat, a thrust actuated control, wherein the improvement comprises: thrust sensor means positioned between the stem nut and the stem nut lock means for sensing axial displacement of the stem nut in the second axial direction resulting from axial compressive thrust on the stem; and switch means operatively coupled with the thrust sensor means and with the motor drive means for actuation to stop the operation of the motor drive means to stop rotation of the stem nut when the axial displacement of the stem nut exceeds a predetermined limit proportional to a predetermined compressive thrust on the stem.
Claim 2
Dependent Claim
233 words
In a motor operated valve, having a motor operator including motor drive means, a stem nut coupled to the motor drive means for rotation about an axis and stem nut lock means coupled to the motor drive means for preventing axial movement of the stem nut, the valve including a valve gate, a valve seat and a valve stem coupled to the valve gate, the valve stem threadingly engaging the stem nut for axial movement in a first direction upon rotation of the stem nut in a first direction to move the valve gate toward and into engagement with the valve seat and for axial movement in a second direction upon rotation of the stem nut in a second direction to move the valve gate out of engagement with and away from the valve seat, a thrust actuated control, wherein the improvement comprises: thrust sensor means positioned between the stem nut and the stem nut lock means for sensing axial displacement of the stem nut in the second axial direction resulting from axial compressive thrust on the stem; and switch means operatively coupled with the thrust sensor means and with the motor drive means for actuation to stop the operation of the motor drive means to stop rotation of the stem nut when the axial displacement of the stem nut exceeds a predetermined limit proportional to a predetermined compressive thrust on the stem.
Claim 3
Dependent Claim
27 words
The control as recited in claim 1 wherein the thrust sensor means comprises a spring assembly installed between the stem nut and the stem nut lock means.
Claim 4
Dependent Claim
37 words
The control as recited in claim 2 wherein the spring assembly includes at least one spring member, the spring member being compressed in proportion to the axial movement of the stem nut in the second axial direction.
Claim 5
Dependent Claim
78 words
The control as recited in claim 3 wherein the spring assembly includes a first spring holder coupled to the stem nut lock means and a second spring holder engaging the stem nut for axial movement therewith and wherein the at least one spring member extends between the first and second spring holders whereby movement of the stem nut in the second axial direction moves the second spring holder toward the first spring holder to compress the spring member.
Claim 6
Dependent Claim
34 words
The control as recited in claim 4 wherein the second spring holder is coupled with the switch means whereby a predetermined movement of the second spring holder results in actuation of the switch means.
Claim 7
Dependent Claim
41 words
The control as recited in claim 5 wherein the switch means is positioned at a location remote from the spring assembly and wherein the spring assembly further includes an extension member for coupling the second spring holder with the switch means.
Claim 8
Dependent Claim
24 words
The control as recited in claim 6 wherein the extension member is generally tubular and surrounds at least a portion of the valve stem.
Claim 9
Dependent Claim
29 words
The control as recited in claim 4 wherein the spring assembly includes a plurality of generally annular, spaced spring members, each spring member being generally V-shaped in cross section.
Claim 10
Dependent Claim
44 words
The control as recited in claim 8 wherein the size, thickness and number of spring members is selected so that displacement of the second spring holder by at least 0.1 inch results from the application of the full rated thrust of the valve operator.