US 3261958 A
Description (OCR text may contain errors)
July 19, 1966 c. w. BlTTNER 3,261,958
IMPULSE ACTUATOR Filed April 15, 1965 s Rs &
INVENTOR. (HA/WEI W. E/TTMS? United States Patent 3,261,958 IMPULSE ACTUATOR Charles W. Bittner, Cherry Hill, N .J assignor to Precision Parts Company, Inc., Pennsauken, N.J., a corporation of New Jersey Filed Apr. 13, 1965, Ser. No. 447,685 7 Claims. (Cl. 200-172) This invention relates generally to impulse actuators, and is especially concerned with impulse actuators for switches.
As is well known to those versed in the art, it is often desirable that an electric switch not be tied down for an extended period, say for safety reasons in the opera tion of presses and other machinery. One practice in this regard is to employ a pair of normally open, springpressed switches requiring simultaneous actuation by both the operators hands. However, it has been found that piece-rate operators are tempted to permanently tie down one of the switches in order to increase their output, but at great risk to their safety.
It is in such situations, and in many other applications that switch closure is required for a relatively short period, independent of the length of time an operator a-ctuates the switch.
It is an important object of the present invention to provide an impulse-type switch actuator which insures that an associated switch will be closed, or otherwise operated, for only a relatively short period, regardless of the period of actuation by an operator.
It is another object ofthe present invention to provide an impulse switch actuator of the type described which is extremely simple in construction, foolproof in operation, durable and reliable throughout a long useful life, and which can be economically manufactured for sale at a reasonable price.
Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a material part of this disclosure.
The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter described, and of which the scope will be indicated by the appended claims.
In the drawings:
FIGURE 1 is a longitudinal sectional view showing a switch actuator of the present invention in association with a conventional switch, and illustrating the normal, nonuse condition; and
FIGURE 2 is a sectional view similar to FIGURE 1,
but showing the switch actuator in its actuated condition,
and illustrating in dot-and-dash outline the condition upon continued actuation of the actuator.
Referring now more particularly to the drawings, and specifically to FIGURE 1 thereof, a conventional switch is there generally designated 10, and may include a fixed casing 11, a threaded nipple 12 extending from the cars ing, and a spring-pressed push button 13 extending through and beyond the nipple.
Associated with the switch is an impulse actuator of the present invention, generally designated 15. The actuator 15 includes a generally cylindrical inner member 16 having an axial thru bore 17. The lower end of bore 17 is enlarged and internally threaded, as at 18, for firm threaded securement of the inner cylinder or member 16 to the nipple 12. In this manner, the lower end 19 of the inner cylinder 16 may be secured fast to the switch casing 11.
The switch button 13 may project, in its released condition of FIGURE 1, upward into an intermediate portion 20 of bore 17, terminating in a downwardly facing shoulder 21. A vent hole or opening 22 may extend through the inner cylinder 16 between the medial bore region 20 and the exterior of the cylinder, for a purpose appearing presently.
Slidably mounted in the upper region of bore 17 is a free piston 25, having an O-ring 26 or other suitable sealing means circumposed thereabout and closely fitting with the interior surface of the bore. At the lower end of piston 25 is an annular enlargement of head 27 located in the medial bore portion 20 and limiting upward piston movement by engagement with the downwardly facing shoulder 21. As seen in FIGURE 1, the piston 25 is engageable on its underside with the upper end of switch push button 13, and the piston is movable downward to depress the switch button and operate the switch 10.
Slidably circumposed about the inner member or cylinder 16 is an outer member or cylinder 30. As seen in FIGURE 1, the lower region of outer cylinder 30 is slidably circumposed about the upper region of inner cylinder 16, and the inner cylinder may have an upper region ekternally grooved, as at 31, for receiving an O- ring 32 or other suitable means sealing the sliding connection between the inner and outer cylinders. Further, the inner cylinder may be provided with one or more radially projecting stop members 33 respectively received in longitudinally extending slots 34 of the outer cylinder to constrain the latter to longitudinal sliding movement within the limits imposed by engagement of stops 33 with opposite ends of theirreceiving slots 34.
The upper region of the outer cylinder 30 extends upward beyond the upper end of inner cylinder 16 and may be provided with an enlarged closure plug orhead 35 having a reduced portion 36 force-fit in the upper end of the outer cylinder. Upward beyond the cylinder 30 the closure plug or knob 35 is enlarged to provide a convenient manual push element.
It will now be appreciated that the outer cylinder 30 is closed at its upper end by the knob 35, and at its lower end by the inner cylinder 16, so as to define within the outer cylinder an expansile and contractile chamber 37, expanding upon upward movement of the outer cylinder and contracting upon downward movement thereof. The chamber 37 communicates downwardly through the upper end of inner-cylinder bore 17 with the upper side of piston 25, for a purpose appearing presently.
Suitable resilient means, such as a coil compression spring 38 is located in the chamber 37, having its opposite ends respectively engaging the closure 35 and upper end of inner cylinder 16 to urge the outer cylinder 30 to its uppermost position. This then is the normal, nonuse condition.
In an upper end region of the outer cylinder 30 is located a relatively small or constricted thru hole or vent opening 40, so as to remain unobstructed in all positions of outer-cylinder movement. In addition, a relatively large vent passageway or opening 41 may be provided through the closure 35. Associated with the internal end of passageway 41 is a one-way valve 42 adapted to permit the ingress of air to the chamber 37 and prevent the egress of air therefrom. In particular, the valve 42 may be a flap valve having a flexible flap 43 secured at one end to the inner or under-surface of closure 35 by a suitable fastener 44.
-In the nonuse condition of FIGURE 1, the outer cylinder 30 and its closure knob 35 are raised to their uppermost position, and the piston 25 rests on the push button 13 which is spring-pressed upward to locate the piston at its uppermost position.
Upon actuation or downward movement of the closure knob 35 and outer cylinder 30, as by hand movement in the direction of arrow 45 in FIGURE 2, the chamber 37 is contracted against the force of spring 38, and the internal pressure of the chamber is increased by the reduc tion in volume. This increase in chamber pressure is transmitted through inner-cylinder bore 17 to the upper side of piston to move the latter downward, and the-reby effect depression of push button 13 to operate switch It). Upon initial downward movement of outer cylinder to the position of FIGURE 2, the valve 42 remains closed and the vent opening 40 is too small to permit rapid escape of air. Hence, the pressure in chamber 37 necessarily increases to efiect the above-described piston and switch-button depression.
If the knob is promptly released, the spring 38 moves the cylinder 30 upward to expand the chamber 37. Should vacuum occur upon expansion of the chamber 37, the valve 42 opens to equalize chamber pressure with atmosphere and insure rapid upward return of the cylinder 30 to its upper limiting position. Of course, the piston 25 is pneumatically released to move upward under the restoring force of push button 13 upon upward movement of the cylinder 3%. The vent 22 at alltimes comrnunicates with the atmosphere to prevent the build-up of excess pressure or vacuum in the bore 17 on the underside of piston 25.
Should an operator retain the knob 35 in its lower-most position for an extended period, the increased pressure in contracted chamber 37 is gradually relieved through constricted vent 40. This permits pneumatic release and upward movement of piston 25 and push button 13 by the spring pressed action of the latter. Hence, it is impossible for an operator to obtain operation of the switch 10 for a period longer than that determined by the rate of air escape through vent opening 40.
From the foregoing, it is seen that the present invention provides an impulse switch actuator which fully ac complishes its intended objects and is well adapted to meet practical conditions of manufacture, installation and use.
Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of the invention and scope of the appended claims.
What is claimed is:
1. An impulse actuator for a pushbutton switch or the like, said actuator comprising an inner cylinder adapted to be fixed to a switch casing and movably receiving the switch button, a piston freely movable in said inner cylinder and adapted to be engageable with said switch button to depress and release the latter, an outer cylinder mounted on said inner cylinder for movement between actuating and deactuating positions and combining with said inner cylinder to define a chamber pneumatically communicating with one side of said piston, said chamber contracting and expanding upon outer-cylinder movement to its respective actuating and deactuating positions to move said piston for respective depression and release of said switch button, and resilient means urging said outer cylinder to its deactuating position expanding said chamber and releasing the switch button, said chamber having a constricted vent opening for gradually releasing pneumatic pressure from said chamber when the latter is contracted, whereby movement of said outer cylinder to and continual retention in its actuating position results in only temporary switch-button depression.
2. An impulse actuator according to claim 1, in combination with a onc-way inlet valve in a wall of said outer cylinder for quickly releasing vacuum in said chamber and facilitating rapid outer-cylinder movement to its deactuating position.
3. An impulse actuator according to claim 2, in combination with stop means limiting the movement of said outer cylinder on said inner cylinder to its actuating and deactuating positions.
4. An impulse actuator according to claim 2, said inner cylinder having additional vent means communicating with the other side of said piston to facilitate piston movement depressing said switch button.
5. An impulse actuator for a push button switch or the like, said actuator comprising an inner cylinder adapted to be fixed relative to a switch casing surrounding the switch button, a piston slidable in said inner cylinder having one side adapted to be engageable with the push button for depressing and releasing the latter, an outer cylinder slidably surrounding said inner cylinder and having one end closed to define with said inner cylinder an expansile and contractile chamber in fluid commuication with the other side of said piston, movement of said outer cylinder to contract and expand said chamber effecting movement of said piston to respectively depress and release said push button, and resilient means urging said outer cylinder toward its chamber-expanding position, said chamber having a constricted vent for gradually releasing pneumatic pressure from said chamber when the latter is contracted, whereby movement of said outer cylinder into and retention in its chamber-contracting position effects temporary switch-button depression.
6. An impulse actuator according to claim 5, said constricted vent being located in said outer cylinder adjacent to the closed end thereof, to remain open in all positions of outer-cylinder movement.
7. An impulse actuator according to claim 6, in combination with a one-way inlet valve in a wall of said outer cylinder for quickly releasing vacuum in said chamber and facilitating rapid outer-cylinder movement to expand said chamber, and stop means on said inner and outer cylinders limiting movement of the latter to extreme positions actuating and deactuating the switch button, said inner cylinder having additional vent means communicating with said one side of said piston to facilitate piston movement depressing said switch button.
No references cited.
ROBERT K. SCHAEFER, Primary Examiner.