AU597453B2

AU597453B2 - Electric motor driven linear actuator with electro-magnetic release

Info

Publication number: AU597453B2
Application number: AU82559/87A
Authority: AU
Inventors: Peter Norris Yeatman
Original assignee: Colt International Ltd
Current assignee: Colt International Ltd
Priority date: 1986-12-16
Filing date: 1987-12-15
Publication date: 1990-05-31
Anticipated expiration: 2007-12-15
Also published as: AU8255987A; NZ222941A

Description

1 597453 COMMONWEALTH OF AUSTRALIA FORM PATENTS ACT 1952 COMPLETE SPECIFICATION FOR OFFICE USE: Class Int.Class .Application Number: Lodged: 'Complete Specification Lodged: S• Accepted: 'published: Priority: Related Art: This document contains the amendments made under Section 49 and is correct for Sprintin g.

SName of Applicant: COLT INTERNATIONAL LIMITED Address of Applicant: New Lane, Havant, Hampshire, P09 2LY, England Actual Inventor, Peter Norris Yeatman Address for Service: SHELSTON WATERS, 55 Clarence Street, Sydney Complete Specification for the Invention entitled: "ELECTRIC MOTOR DRIVEN LINEAR ACTUATOR WITH ELECTRO-MAGNETIC RELEASE"

I

The following statement is a full description of this invention, including the best method of performing it known to me/us:- 1 -s

I

t.

w 1A ELECTRIC MOTOR DRIVEN LINEAR ACTUATOR WITH ELECTRO-MAGNETIC RELEASE *4*W 4 4.

4 4 *4 .10 4 44 54 4 44 *4 i Sc c 4* 44 4 4* 4 44 4444 .4i ii r C *.4 This invention relates to ventilators which term is to be taken to include automatic windows and doors which may be used as fire ventilators and/or for smoke control in emergencies, and concerns electro-mechanical controls for opening and closing such ventilators.

It is well known to provide ventilating systems requiring the impartation of a linear movement to a ventilator control member upon the operation of two different control systems to open or close a ventilator or a series of ventilators. Typically a ventilator may be required to be opened or closed under the control both of say a normal, day-to-day ventilation management system and opened or fully opened or closed under the control of say an emergency fire ventilation system.

(B-A-2,167,552 describes a ventilator having an electro'mechanical control nmechanism capable of responding to both normal and emergency systems comprising a linear actuator operable to open and close the ventilator via a force transmitting member formed in two sections whi0 h are normally retained telescoped one with respect to the other by an electro4.magnetic device mounted on one of the sections and ak electromagnetic keeper plate mounted on the other of the lip 00101116'"1 1- y w L

II.

2 sections, energising means being provided tending to extend the force transmitting member, In this prior art arrangement, the linear actuator takes the form of a pneumatic piston and cylinder of which the piston rod constitutes one section of the force transmitting member.

GB-A-2,167,552 also describes a ventilator having a control mechanism comprising an electric motor operable to drive a crank arm connected to the force transmitting member.

9 94 10 There is a need to provide, in a ventilator, an electric motor powered linear actuator capable of responding to two different control systems. Such actuators not only may conveniently be housed in the ventilator frame in direct replacement for a pneumatically operated linear actuator, but *also they may be used as back-up actuators for emergency operation in substituion for failed controls.

According to the present invention, there is provided a ventilator having an elactro-mechanical control mechanism hI t t •et comprising a linear actuator operable to open and close the ventilator via a force transmitting member formed in two sections which are normally retained telescoped one with respect to the other by an electro-magnetic device mounted on one of the sections and an electro-magnetic keeper plate mounted on the other of the sections, energising means being provided tending'to extend the force transmitting member and :c: 2A open the ventilator upon de-energisation of the electromagnetic device, and the linear actuator comprises a reversible electric motor and co-operating screw threaded elements one of which is arranged to be driven by the reversible electric motor thereby to move the other to displace the force -ransmitting member to open or to close 0 o the ventilator or to displace one section of the force transmitting member into its normal telescoped relationship .9 r. with the other section of the force transmitting member to a I 10 enable it to be retained in that relationship by reenergisation of the electro-magnetic device.

Preferably, one section of the force transmitting_ 9 4996s .9.9a 4. 9 Ir(A tt

I-.

3 member is formed as an internally screw threaded element of said linear actuator, said motor driving an externally screw threaded rod element of said actuator, said rod element being received within the other section of the force transmitting member at least when the two sections of the force transmitting member are retained telescoped by the electro-magnetic device.

a *The accompanying drawing illustrates one specific a a .a embodiment of the present invention by way of example.

10 In the drawing:-

S.

FIG. 1 shows a ventilator control comprising a linear actuator; a a* FIG. 2 shows an elevation, in part in crosssection of the actuator; and 0 a* FIG. 3 shows a modification.

With reference now to the accompanying drawing and first to Fig. 1, a linear actuator 19 for controlling the day-to-day opening and closing of a ventilator such as a louvred ventilator or an automatic window or door or again, a ducted fire ventilator, is connected to operate a member 7 of the ventilator which is bodily movable in opposite directions 9 respectively to open and close the ventilator. Spring energising means such as 8, which may be a gas spring, acts on the member 7 tending to displace the member 7 and open the pf l l x r 4 ventilator. The spring means 8 may act directly or indirectly on the member 7 which may move linearly as illustrated in phantom lines in Fig. 1 or with pivoting at its, pivotal connection 12 with the actuator 19.

The actuator 19 comprises a small reversible S24V d.c. elecric motor 1 which is directly coupled t et S. to drive an externally screw threaded rod 2, the rod 2 extending with its longitudinal axis along the axis 10 of rotation of the motor. A force transmitting member formed in two tubular sections 4, 5 is normally retained with its section 5 telescoped within its section 4 by an electro-magnetic device 3 mounted on the section 4 and an electro-magnetic keeper plate 6 mounted on the section 5. De-energisation of the electro-nagnetic device 3, e.g. under e control of an automatic fire or smoke ventilation system releases

I

the keeper plate 6 and allows the ventilator to open under the action of the spring means 8, the plate 6 then moving to the phantom line position shown in Fig.

1 of the drawing.

Subsequent operation of the motor 1 rotates the rod 2 to advance a nut 23 fixed to the section 4 and screw-threadedly engaged with the rod 2 to extend the section 4 of the force transmitting member 10 from /i /e

J,

a tubular casing 25 of the actuator to move the electromagnetic device 3 into contact with the plate 6.

Re-energisation of the electro-magnetic device 3 then re-sets the ventilator for automatic operation.

In normal day-to-day operation of the ventilator the motor 1 is driven to extend and retract the force transmitting member 10 from the casing 25 to open and 9 to close the ventilator, the section 5 of the member S. being retained telescoped within the section 4 of the 99 10 member and over the rod 2 by the electro-magnetic device 3 magnetically holding the keeper plate 6. Thus, the section *5 of the force transmitting member telescopically receives the rod 2 in order to foreshorten the actuator.

S" The actuator 19 is operable to impart a predetermined start and finish for the displacement of the distal end of the force transmitting member S 10. Thus, a pair of spaced apart, electrical limit switches 27, e.g. micro-switches, are each adjustably mounted as to position in a housing 30 on the casing to be operated by a rod 32 fixed to the device 3 and movable lengthwise in the housing By adjusting the bositions of the switches 27, the member 10 may be set for linear movement by the actuator accurately to fully open, and to fully close, 6 the ventilator as well as to reset the ventilator after its automatic operation in which the device 3 is de-energised. The position of the left-hand switch 27 in Fig. 2 determines the closed position of the ventilator and the position of the right-hand switch in Fig. 2 determines the fully open position of the 6 S10 of the meber 10 to allow the keeper plate to align Fig. 3 illustrates a modification in which the itself with the armature of the device 3. Alternatively, Sthe keeper plate 6 may be mounted to the section *by means of a flexible coupling.

In the event of a power failure, the ventilator "fails safe" as a fire ventilator and moves to its fully open position.

0 1htea Ari iselfwit thearmtureof he dvic 3. ltenatiely 1

Claims

1. A ventilator having an electro-mechanical control mechanism comprising a linear actuator operable to open and close the ventilator via a force transmitting member formed in two sections which are normally retained telescoped one with respect to the other by an electro-magnetic device mounted on one of the sections and an electro-magnetic keeper plate mounted on the other of the sections, energising means G being provided tending to extend the force transmitting member and open the ventilator upon de-energisation of the S. i 10 electro-magnetic device, and the linear actuator comprises a reversible electric motor and co-operating screw threaded elements one of which is arranged to be driven by the Sreversible electric motor thereby to move the other to displace the fcres transmitting member to open or to close the ventilator or to displace one section of the force 9*9 transmitting member into its normal telescoped relationship j with the other section of the force transmitting member to i enable it to be retained in that relationship by re- :9 energisation of the electro-magnetic device.

2. A ventilator as claimed in claim 1, wherein one section of the force transmitting member is formed as an internally screw threaded element of ,aid linear actuator, Ssaid motor driving an externally screw threaded rod element of said actuator, said rod element being received within the k other section of the force transmitting member, at least when the two sections of the force transmitting member are retained telescoped by the electro-magnetic device.

3. A ventilator as claimed in claim 2, wherein the electric motor directly drives the screw threaded rod, the rod extending with its longitudinal I ji 1 4 1, 8 axis along the axis of rotation of the motor.

4. A ventilator as claimed in any preceding claim, wherein carried with said one of said sections of said force transmitting member is a switch operating member for operating limit switches carried by a casing of said actuator, said switches being adjustably 9' positionable along the casing to pre-set the start and finish of the displacement of the force transmitting member. o

5. A ventilator as claimed in any preceding claim, wherein the keeper plate is flexibly or loosely mounted to the other of the sections of the force transmitting member.

6. A ventilator having an electro-magnetic control mechanism substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings. DATED this 15th day of December, 1987 COLT INTERNATIONAL LIMITED Attorney: PETER HEATHCOTE Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS