Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
213 words
An electric actuator comprising an electric motor for determining the output force generated on an output member by a spring means; a drive shaft driven by the electric motor and comprising first and second drive means, a first driven means driven by said first drive means, a non-rotational but axially movable intermediate member which is threadedly engaged with said first driven means; said spring means comprising spring, located between the intermediate member and the output member, for transmitting axial movement of the intermediate member to the output member so long as the output member is free to move and for, when the output member is restrained from movement, generating the output force on the output member upon continued operation of the electric motor; a second driven means driven by said second drive means; a stop means, carried by the intermediate member and adjustable in position with respect thereto in the direction in which the intermediate member is axially movable, for engaging the second driven means to arrest the rotation thereof and to thus arrest rotation of the second drive means and, hence, by thus arresting rotation of the second drive means, to arrest further operation of the electric motor in the direction thereof which increases the output force generated on the output member.
Claim 2
Dependent Claim
213 words
An electric actuator comprising an electric motor for determining the output force generated on an output member by a spring means; a drive shaft driven by the electric motor and comprising first and second drive means, a first driven means driven by said first drive means, a non-rotational but axially movable intermediate member which is threadedly engaged with said first driven means; said spring means comprising spring, located between the intermediate member and the output member, for transmitting axial movement of the intermediate member to the output member so long as the output member is free to move and for, when the output member is restrained from movement, generating the output force on the output member upon continued operation of the electric motor; a second driven means driven by said second drive means; a stop means, carried by the intermediate member and adjustable in position with respect thereto in the direction in which the intermediate member is axially movable, for engaging the second driven means to arrest the rotation thereof and to thus arrest rotation of the second drive means and, hence, by thus arresting rotation of the second drive means, to arrest further operation of the electric motor in the direction thereof which increases the output force generated on the output member.
Claim 3
Dependent Claim
19 words
An electric actuator as claimed in claim 1, further comprising means for measuring the rotation of the drive shaft.
Claim 4
Dependent Claim
18 words
An actuator as claimed in claim 1, further comprising key means for restraining the intermediate member against rotation.
Claim 5
Dependent Claim
36 words
An actuator as claimed in claim 1 wherein said first driven means comprises a gearwheel and the intermediate member has a ball-screw portion which threadedly engaged with said gearwheel so that said gearwheel constitutes a nut.
Claim 6
Dependent Claim
14 words
An actuator as claimed in claim 1, wherein the spring is a compression spring.
Claim 7
Dependent Claim
28 words
An actuator as claimed in claim 1, wherein the stop means comprises a collapsible stop which is collapsible in the direction of axial movement of the intermediate member.
Claim 8
Dependent Claim
43 words
A actuator as claimed in claim 1, wherein the stop means includes a portion which is threadedly engaged with the intermediate member so as to be axially positionally adjustable with respect thereto by relative rotation of the stop means and the intermediate member.
Claim 9
Dependent Claim
20 words
An actuator as claimed in claim 1, wherein said second driven means comprises gearwheel rotationally carried on the output member.
Claim 10
Dependent Claim
22 words
An actuator as claimed in claim 1 wherein the said second driven means includes a clutch face engageable by the stop means.
Claim 11
Dependent Claim
15 words
An actuator as claimed in claim 1 wherein said actuator constitutes a railway brake actuator.