| United States Patent | 3,585,543 |
| Taylor | June 15, 1971 |
THREE POSITION SWITCH
Abstract
A three position toggle switch is locked by a deenergized solenoid in a first or "off" position. The switch cannot be moved to a second position until the solenoid is energized, and cannot be moved beyond the second position or to a third position until hand pressure is removed from the toggle to release a mechanical lock, after which the solenoid is manually overridden for movement to the third position.
| Inventors: | Taylor; Andrew R. (Fairlawn, NJ) |
| Assignee: |
The Bendix Corporation
( |
| Appl. No.: | 04/888,691 |
| Filed: | December 29, 1969 |
| Current U.S. Class: | 335/169 ; 74/104 |
| Current International Class: | H01H 3/32 (20060101); H01H 3/50 (20060101); H01h 009/20 () |
| Field of Search: | 335/169,164,167 74/99,102,103,104,105,106,471,479 |
| 818783 | April 1906 | Philippi |
| 3187120 | June 1965 | Akst |
| 3241640 | March 1966 | McCordic |
What I claim is:
1. Toggle mechanism, comprising:
a frame having a fixedly mounted pivot;
a lever having a fixedly mounted pin and mounted on the frame pivot to pivot thereabout;
a handle having an enlarged hole surrounding the lever pin and fixedly mounted pivot, and mounted on the frame pivot to pivot thereabout;
an arm having a slot for engaging the lever pin and a clearance slot for the frame pivot, and mounted on the handle pivot to pivot thereabout; and
a predetermined angular displacement of the handle away from a first position in one sense causing the lever pin to engage the handle hole for pivoting the lever about the frame pivot in the one sense and for causing the arm engaged with the lever through the arm slot and lever pin for pivoting about the handle pivot in the opposite sense.
2. Mechanism as described by claim 1, including:
a clevis mounted to the lever and having a finger member which moves linearly when the lever pivots about the frame pivot;
a pawl mounted to pivot about the frame and actuated by the clevis finger to lock the handle when the handle is in a second position.
3. Mechanism as described by claim 2, including:
a spring for coupling the handle and the lever, and arranged to provide a resisting force when the handle is moved away from the first position;
said spring being effective upon release of pressure on the handle for causing springback of the handle in the opposite sense to the first position and movement of the arm in the one sense; and
the pawl and arm being in cooperative arrangement so that said movement of the arm in the one sense actuates the pawl to unlock the handle.
4. Mechanism as described by claim 3, including:
the pawl having a pair of detents in corresponding relation to the handle locking and unlocking positions of the pawl; and
retaining means mounted to the frame for engaging one of said detents when the pawl is in a corresponding position for retaining the pawl thereat.
5. Mechanism as described by claim 1, including:
a latch mounted to the lever and having a detent therein; and
a solenoid and a cam actuated by the solenoid; and
said cam and latch being cooperatively arranged so that when the solenoid is deenergized the cam engages the latch detent for locking the handle in the first position.
6. Mechanism as described by claim 5, wherein:
the lever has a pair of detents corresponding to second and third switch positions;
energizing of the solenoid disengages the cam from the latch detent for movement of the handle from the first position to the second position and for engagement of the cam in the lever detent corresponding to said second position.
7. Mechanism as described by claim 6, wherein:
the solenoid is manually overpowered to move the switch from the second to third positions, with the cam being disengaged from the second position detent and engaged in the third position detent.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to multiposition toggle switches, and more particularly to switches of the type described which are mechanically locked in the "off" position.
2. Description of the transportation Art
Automatic control systems for aircraft require switching devices for connecting the system in appropriate flight modes. For example, when an aircraft is engaged in autopilot configuration it is necessary to switch to and from the command mode (the mode for controlling the craft in response to autopilot commands) and the control wheel steering or CWS mode (the mode whereby the human pilot manually overrides the autopilot). Moreover, delays or lags are required when switching from one mode to the other in order to allow time for engagement of appropriate circuitry. Prior to the present invention, there has not been a switch for accomplishing these purposes.
SUMMARY OF THE INVENTION
This invention contemplates a three position toggle switch including a handle initially locked by a deenergized solenoid in a first or "off" position, a pivotally mounted lever and an arm. The arrangement is such that when the solenoid is energized the handle may be manually moved from the "off" position to a second position. When moved to the second position the handle moves through a predetermined angular distance before actuating the lever to a detent held position. When the handle is in the second position, it engages a pawl so as to be locked thereby. When hand pressure is removed from the handle, spring action moves the handle back through the angular distance, whereupon the arm actuates the pawl to release the handle lock. The handle is held in the second position by the energized solenoid, and upon overpowering the solenoid the handle is moved to a third position. When the solenoid is deenergized, the handle returns to the "off" position and the pawl is positioned for the next operating cycle.
One object of this invention is to provide a three position toggle switch mechanically locked in the first or "off" position.
Another object of this invention is to provide a three position toggle switch whereupon the switch handle cannot be moved beyond the second position until hand pressure is removed therefrom.
Another object of this invention is to hold the switch in the second position by a solenoid operated detent arrangement.
Another object of this invention is to provide a switch of the type described whereby the switch handle is moved from the second to the third positions by manually overriding the solenoid.
The foregoing and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for illustration purposes only and is not to be construed as defining the limits of the invention.
The single FIGURE in the drawing is a schematic diagram of a switch according to the invention.
The device of the invention as shown in the FIGURE includes a lever C having an integral or fixedly mounted pin 1 and arranged to pivot about a pivot 7 fixedly mounted or integral to a frame 20. A handle A has an enlarged hole 2 therein, and is mounted over lever C so that hole 2 surrounds pin 1 of lever C. Handle A is arranged to pivot on pivot 7 and the handle, in turn, has an integral or fixedly mounted pivot 3 thereon. Handle A and lever C are coupled by a spring G. Spring G is mounted to handle A at a stud 10 and is mounted to lever C at a stud 12.
Handle A has a corner 4 having a purpose as will be hereinafter described, taken lever C has a pair of detents 14 and 16. Detent 14 receives a solenoid cam 17 actuated by a solenoid 17A when the system is engaged in the control wheel steering (CWS) mode and detent 16 receives cam 17 when the system is engaged in the command mode.
An arm B has an open ended elongated slot 9, and is mounted over handle A with slot 9 engaging pin 1. Arm B is arranged to pivot on pivot 3 of handle A and further includes an elongated slot 11 which surrounds pivot 7 of frame 20.
A latch 19 is mounted to lever C at a mounting point 21 and includes a detent 23. When solenoid 17A is deenergized cam 17 is engaged in detent 23 and prevents movement of lever C, thereby locking the switch in "off" position shown in the FIGURE.
Lever C has an arm 30 mounted thereto at a mounting point 32. A clevis 34 is mounted to arm 30 at mounting points 36 and 38, and which clevis 34 includes a finger 40 carrying an integral or fixedly mounted pin 6. Clevis 34 includes a shaft which moves linearly when lever C pivots about pivot 7 for appropriately indexing conductive and nonconductive elements of the switch (not shown) as will now be understood.
A pawl D is arranged to pivot about a configurations of 18, and which pivot 18 may be mounted to frame 20. Pawl D has a finger 22 and detents 24 and 26. A spring K is mounted to frame 20 at points 28 and 30 and retains pawl D in a desired detent position as will hereinafter be seen.
When the aircraft is engaged in autopilot configuration, solenoid 17A is manually or automatically energized so that cam 17 thereof drops from detent 23 to the surface of lever C having detents 14 and 16. Handle A is moved clockwise from its first or "off" position, and travels a predetermined angular distance, for example 8.degree., before pin 1 of lever C engages the lower edge of hole 2 of handle A, causing lever C to move clockwise whereupon detent 14 engages cam 17. At this time spring G is extended. Lever B pivots counterclockwise about pin 3 due to the action of pin 1 pushing on the lower edge of slot 9 before pin 1 engages the lower edge of hole 2. When handle A is in the control wheel steering (CWS) position shown in the FIGURE, corner 4 of handle A engages finger 22 of pawl D, locking handle A in position. Pawl D is retained in the locking position by the action of spring K in detent 24.
When hand pressure is released from handle A it springs back to its original position because of the spring action affected by spring G. This causes arm B to pivot clockwise about pin 3 so that a pin 5 on arm 4 actuates pawl D, thereupon releasing the lock affected by the engagement of finger 22 of pawl D and corner 4 of handle A. Pawl D is held in position by the action of spring K in detent 26 as shown in the FIGURE.
Handle A is held in the CWS position by the engagement of cam 17 in detent 14, and upon manually overpowering the solenoid, handle A can be moved from the CWS to command positions shown in the FIGURE, with cam 17 being thereupon engaged in detent 16 of lever C. When the solenoid is either manually or automatically deenergized, cam 17 overrides the detent position and handle A returns to "off." At this time, pin 6 on clevis 34 restores pawl D to its original position as the clevis moves linearly in preparation for the next switching cycle.
It will now be seen from the foregoing description of the invention that when solenoid 17A is deenergized, the switch is mechanically locked in the "off" position due to the action of cam 17 in detent 23. Handle A cannot be moved to the CWS position until solenoid 17A is energized. Handle A cannot be moved beyond the CWS position or the command position until hand pressure is removed from the handle. When handle A is in the CWS position and hand pressure is removed, the mechanical lock affected by the action of finger 22 in corner 4 is released and the switch is held in the CWS position by the engagement of solenoid cam 17 and CWS detent 14. Handle A can now be moved from the CWS position to the command position by manually applying sufficient force to overpower the solenoid held cam in detent 14. When the solenoid is deenergized, handle A overrides the detents and returns to the "off" position. The ensuing delays affected by the aforegoing mechanical interaction provide sufficient time for associated electronic circuitry to become operative.
Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangements of the parts, which will now appear obvious to those skilled in the art may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a definition of the limits of the invention.
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