US3153706A

US3153706A - Pneumatically-timed contact-holder

Info

Publication number: US3153706A
Application number: US152224A
Authority: US
Inventors: Faffart Andre Georges
Original assignee: TELEMCANIQUE ELECTR
Current assignee: LA TELEMCANIQUE ELECTRIQUE; TELEMCANIQUE ELECTR
Priority date: 1960-11-19
Filing date: 1961-11-14
Publication date: 1964-10-20
Anticipated expiration: 1981-10-20
Also published as: BE609131A; LU40725A1; FR1280123A; ES270979A1

Description

Oct. 20, 1964 e. FAFFART 3,153,706

PNEUMATICALLY-TIMED CQNTACT-HOLDER Filed Nov. 14, 1961 4 Sheets-Sheet 1 Oct. 20, 1964' A. G. FAFFART PNEUMATICALLY-TIMED CONTACT-HOLDER 4 Sheets-Sheet 2 Filed Nov. 14, 1961 Oct. 20, 1964 A. G. FAFFART 3,153,706

PNEUMATICALLY-TIMED CONTACT-HOLDER Filed Nov. 14, 1961 4 Sheets-Sheet 3 52A 5285M 10 42mg Oct. 20, 1964 A. G. FAFFART 3,

PNEUMATICALLYTIMED CONTACT-HOLDER Filed Nov. 14, 1961 4 Sheets-Sheet 4 g Ami:

United States Patent 3,153,706 PNEUMATICALLY-TIMED CONTACT-HOLDER Andr Georges Falfart, Nanterre, Seine, France, assignor to La Telemecanique Electrique, Nanterre, France, a

joint-stock company of France Filed Nov. 14, 1961, Ser. No. 152,224 Claims priority, application France, Nov. 19, 1960, 844,446 4 Claims. (Cl. 260-34) There is known to exist electric current switches which are operated by depressing a push-button and which main tain the contact thus established for a certain length of time, thereafter cutting-oil under the effect of a pneumatic timing device.

There are also known to exist pneumatically-timed contact relays which are remotely-operated by an electromagnet.

Both of these types of apparatus require mechanisms and arrangements particular to each manner of operation. Moreover, the time-delay relays are generally bulky and of a complicated construction.

The main object of the present invention is to provide a pneumatic timing device overcoming the drawbacks of the devices presently known in that it can be adapted in a very simple manner for use either with a manual control push-button or with a relay or electromagnetic contactor.

Another object of the invention is to provide a timing device of the above-mentioned type but of little bulk and of a rational form.

Yet another object of the invention is to provide a timing device of the aforementioned type constituted by parts which are very easy to mount merely by placing them on top of one another, which enables the cost price of the apparatus to be lowered.

The pneumatic contact timing device conforming to the invention is essentially characterized by the fact that it comprises the combination of: a casing, in which is mounted a snap action switch whose central actuator can be operated from the outside of the casing; an operating body comprising a fore chamber and a rear chamber; a central channel connecting the fore chamber to the rear face of the operating body; a second channel, provided with an air intake throttling device, connecting the rear chamber to the fore chamber; two flexible membranes disposed on either side of the operating body and defining the volumes of the fore and rear chambers, the membrane located against the rear face of the operating body forming, in addition, a valve between the central channel and the rear chamber; a membrane push-rod adapted to push the fore membrane against the action of a resilient return system located Within the fore chamber and to force the air contained in this latter chamber through the central channel and the valve into the rear chamber, the operating body, the push-rod and the contact casing being disposed with respect to each other in such a way that any action, manually or remotely-controlled, exercised on the control push-rod for the snap action switch causes the displacement of the control push-rod and vice versa, the duration of the displacement being regulated in this latter case by the velocity with which the air contained in the rear chamber can pass through the air intake throttling device to return to the fore chamber.

Between the manually-operated push-button on the one hand and the actuator of the snap action switch together with the push-rod of the membrane on the other hand, there is advantageously provided, more particularly in the case of direct manual control, an intermediate connection system, selective of the order of the operations, which is actuated in such a Way that the push-rod of the membrane terminates its movement before the push-rod of the circuit-breaker can be operated.

In the case of remote control, the assembly is provided with an external lateral strap which is slideable and adapted to act on the control rod for the snap action switch, this strap itself being acted upon by the mobile armature of a contactor or electromagnetic relay, this arrangement enabling the timing to be made either from the closing or from the opening of the relay by simply reversing the unit end-to-end with respect to the mobile armature of the contactor or electromagnetic relay.

In order to ensure that, even in the case of careless assembly, the armature of the relay is completely closed before the actuator of the snap action switch terminates its movement, the external lateral strap acts on this actuator through the intermediary of a leaf spring.

Other features and advantages of the present invention will become clear from the following description with reference to the accompanying drawings, illustrating schematically, and merely by way of example, different possible embodiments of the said invention.

In these drawings:

FIGURE 1 is an axial longitudinal section of the whole of a timing block conforming to the invention adapted for manual control, the different mobile members of this assembly being represented in the respective positions which they occupy immediately after the circuit-breaker has been actuated and following the moment when the pneumatic timing device starts to operate.

FIGURE 2 is a detail to a smaller scale illustrating a plan view of the contact casing within which the snap action switch is mounted.

FIGURE 3 is a detail to the same scale as FIGURE 2 illustrating a plan View of the operating body acting as a pumping chamber and valve seating. I

FIGURE 4 is a cross-section of the operating body, this section being taken along line IVIV of FIGURE 3.

FIGURES 5 and 6 are details to a larger scale than the preceding details, representing the snap action switch in its two extreme operating positions.

FIGURES 7, 8 and 9 are explanatory diagrams of the working principle of the manual control members of the timer block illustrated in FIGURE 1;

FIGURES l0 and 11 are partially-sectioned elevations of two possible assemblies for a timing block conforming to the invention on the base-plate of a control contactor or electromagnetic relay, the timing taking place as from the closing of the relay in the case of FIGURE 10 and as from the opening of the relay in the case of FIGURE 11.

FIGURE 12 is a detail representing, seen from one end, the external lateral strap enabling the central push-rod of the timer to be acted on in the two preceding cases.

The ensemble of a timing block conforming to the invention essentially comprises: an operating body, designated by the general reference 1 and arranged in a known manner between two

flexible membranes

2 and 3, made for instance, of rubber, this operating body acting as a pumping chamber and valve seating as will be seen in detail further on; a rear cover designated by the general reference 4 which serves as a'seating for a discharge valve 5 and as a support for a tapped member 6 in which is lodged an adjusting screw 7 enabling, as will be seen in detail further on, the desired value of timing to be set; a sub-assembly comprising a screen 8, a contact casing 9 and a cover lti, this sub-assembly forming a housing containing a snap action switch of any known type, designated by the general reference 11, as well as the guiding members for membrane 2, designated by the general reference 12.

The dilferent component parts of the ensemble of the timer block which have just been enumerated are mounted simply by stacking them one above the other and attaching them by means of longitudinal assembly rivets such as the rivet 13 shown in dotted lines in FIGURE 1. These rivets, which ensure that the apparatus is not upset in use, are tubular so as to be able to serve, as shall be described in detail further on, both for the securing of said timing block onto a base-plate receiving either a direct manual control device (FIGURES 1, 8 and 9) or an electromagnetic contnol device (FIGURES 10 and 11), and the sliding of the control strap for the circuit-breaker in the case of electromagnetic control.

More particularly, the operating body 1 (see FIGURES 1, 3 and 4) has, on its forward or left-hand side face (see FIGURES 1 and 4), a basin of frusto-conical shape 14- is extended by a cylindrical opening 15. The central part of the body is traversed by a channel 16 whose fore part 16A is cylindrical and whose rear part 16B is frusto-conical, these two parts being connected by a medial restriction 16C, for example of square section. On the rear face of body 1 is formed, concentric with the orifice of channel 16C, 21 small flange 17 of triangular section forming an escape valve joint in combination with the central portion 3A of the membrane 3 which is biased by the spring 5A of the valve 5.

In the rear portion of body 1 there is provided: firstly a chamber 18 whose volume is large with respect to that of the fore chamber delimited by the walls of the basin 1d, and of the membrane 2 when this latter occupies the position illustrated in chain-dotted lines in FIGURE 1; and secondly, the housing 19 for the air intake throttling device in the said fore chamber.

This throttling device is advantageously formed, as shown in FIGURES 1, 3 and 4, by a ball 26) in a soft resilient material, such as rubber for instance, which is pressed resiliently into a basin 21 communicating through a channel 22 with the inside of the basin 14. Preferably the basin 21 is in the form of a hollow decapitated pyramid (see particularly FIGURES 3 and 4), such as a tetra hedron for example, whereby a crushing force on the ball leaves, along the arrises of the tetrahedron, air intake channels whose section is variable with the pressure that the ball exerts on its seating 21.

The desired pressure of the ball on its seating is obtained by screwing in or out the adjusting screw 7 whose base abuts against a member 23 which supports the ball 20 and is adapted to slide in the housing 19. A return spring 24 acts to reduce the pressure exerted by the ball on its seating when the adjusting screw 7 is unscrewed.

In front of the membrane 2 there is provided a membrane push-rod 12 adapted to slide longitudinally in the axis of the apparatus in order to cause the said membrane to pass from the position shown by dotted lines in FIG URE 1 to the position shown in full lines on this same figure and to thereby force the air contained in the

fore chamber

14, 15, through the channel 16 then through valve 17, 5, until it reaches the rear channel 18.

In order to completely empty the said fore chamber, the rear face 12A of the membrane push-rod 12 is of shape complementary to that of the basin 14 in the operating body.

On the other hand this membrane push-rod 12 has a central channel 25 wherein there is lodged as a slightly tight fit the fore extremity of a membrane-guide, constituted by a rod 26 having a cylindrical shoulder-piece 27 capable of adapting itself within the cylindrical portion 15 of the basin of the operating body 1. The rear portion of the rod 26 can slide in the channel 16 of the operating body where it is guided by the restriction 16C. By virtue of the fact that the section of the rod 26 is circular whilst that of the restriction is square, it can be seen that the air forced from the fore chamber towards the outer chamber can infiltrate through the free spaces between the rod 26 and its housing 16. A return spring 28, hearing respectively against the restriction 16C and against the rear face of the shoulder-piece 27, biases, in a constant manner, the assembly comprising the membrane-guide 26, the membrane 2 and the member support 12 from the rear towards the front.

Pressure-balancing bleeds are provided between the external chamber 18 and the chamber constituted by the inner volume of the contact casing 9. These balance bleeds can advantageously be formed by interstices between both the assembly rivets 13 and their respective housing 29 in the operating body 1 (FIGURE 3), and 30 in the contact casing 9 (see FIGURE 2).

In order to allow air to infiltrate under the membrane 2 into the housings 29, flarings 31 are provided. Similarly, small channels 32 are formed in the front face of the casing 9 in order to allow the air which circulates in the housings 3G to reach the inner chamber of the contact casing 9.

Within casing & there is mounted a snap action switch of any known type, diagrammatically illustrated at 11 in FIGURE 1. This snap action switch is controlled by an actuator 33 whose fore extremity 33A passes through an orifice 34 provided in the centre of the cover 10 of the contact casing and whose rear extremity 33B, which bears two lateral shoulders, passes through an orifice of corresponding form 35 provided in the rear part of the contact casing 9. The extremity 33B of the contact push-rod comes to bear either against the extremity of the rod 26 of the membrane guide in the position of operation illustrated in FIGURE 1, or against the membrane support 12 during the timing phase, as will be seen in detail further on.

The actuator 33 controls in its turn a snap action switch constituted, for instance, as illustrated in FIGURES 5 and 6, by an undulated spring 36 adapted to move a mobile frame 37 brusquely from a first extreme position, in which it bears against fixed

contact studs

38A, 38B (FIGURES 1 and 5), to a second extreme position in which it bears against fixed contact studs, 39A, 39B (FIGURE 6). These two series of fixed contact studs are connected respectively and in any known appropriate way to current outputs attached to the outside of the

contact casing

9, 449A, 4013 and 41A, 41B which can b distinguished in FIGURES 10 and 11.

As has been seen previously, the control of the contact timing device can be either manual or through a relay or electromagnetic contactor.

A possible embodiment incorporating manual control will now be described by Way of example with reference to FIGURE 1.

The assembly comprising the operating body 1, the

membranes

2 and 3, the rear cover 4, the screen 8, the contact casing 9 and the cover 10, which is assembled by longitudinal rivets 13, forms a whole which is fixed, in the example chosen, to a base-plate 42 by means of a screw 43 passing through the hollow assembly rivets 13-. A cross-piece 45 is mounted between the base 42 and the cover 16 so as to form a chamber 46 within which different intermediate members are actuated to transmit the movement of a push-button mounted in the axis of the device to the apparatus proper. A flexible sealed membrane 47 enables the desired thrust to be made while ensuring effective protection of the assembly of intermediate control members against dust. These latter are to ensure that the

fore air chamber

14, 15 is completely emptied before the cutting-01f of the snap action switch 11 can take place and so that retraction to the rear with timing can only occur as from this particular moment.

The contact casing 9 as well as its cover 10 are provided with lateral orifices 48A, 438 for the cover and 23A, 593 for the casing, disposed in relationship to each other so as to define two longitudinal passages parallel to the axis of the apparatus in which the two branches SiiA, $01 3 of a forked member provided with a sleeve 51 located in the axis of the apparatus can freely slide. In the sleeve axis an intermediate push-rod 52 can slide, its fore extremity 52A receiving the control thrust and its rear extremity 5213 being able to transmit the said thrust to the extremity 33A of the contact push-rod.

A return spring 53 is provided between the cover 19 and the forked member A, 5813 Whilst another return spring 54, much more powerful than spring 53, is provided between the forked member and the head 52A of the intermediate push-rod 52.

The operation of the manual control contact timing device is as follows.

At the start, the different mobile members are located in the following respective positions:

The manual control members proper are in the position illustrated in FIGURE 7;

The members of the snap action switch are in the position illustrated in FIGURE 6;

The actuator 33, the membrane push-rod 12, the membrane 2 and its guide 26 are located completely over to the left in positions opposite to those which they occupy in FIGURE 1.

If, at this moment, through the push-button mounted in the axis of the device, a pressure is exerted in the direction of the arrow F onto the head 52A of the intermediate push-rod 52, the spring 54 being stronger than the spring 53 it will be seen that the assembly of intermediate push-rod 52 and forked member 50A, StiB will be displaced by one stage in the direction of arrow F.

The extremities of the branches 59A, 50B of the forked member come into contact with the membrane push-rod I2 and force this latter in the direction of the arrow F. The length of the branches of the forked member is determined so that the membrane push-rod I2 is forced completely to the right before the extremity 52B of push-rod 52 comes into contact with the head 33A of the actuator. At this moment the manual control mobile members are located in the respective positions illustrated in FIGURE 8.

During this first phase the membrane push-rod 12 has completely forced the membrane 2 into the bottom of the basin 14 of the operating body 1 and the shoulder 27 has adapted itself into the cylindrical basin 15. The result of this is that the air contained in the fore chamber 14, discharges through channel 16, raises the valve 5 and enters the outer chamber 18.

As from this moment when the fore chamber is completely emptied of air and the forked

member

50A, 50B is blocked against the push-rod 12, it can be seen that if pressure is further exerted on the push-rod 52 in the direction of arrow F, this push-rod will displace with respect to the forked member by sliding in sleeve 51, compressing the return spring 54.

From this moment the intermediate push-rod 52 will depress actuator 33 thus provoking operation of the snap action switch 11 which passes from the position illustrated in FIGURE 6 to that illustrated in FIGURE 5.

The mobile members are then located in the relative positions illustrated in FIGURE 1.

If pressure on the intermediate push-rod 52 is discontinued, the timing device itself then comes into action.

The assembly comprising the forked member 50A, 5R8 and intermediate push-rod 52 returns automatically to its initial position illustrated in FIGURE 7 under the action of the return springs 53 and 54.

The assembly comprising the membrane 2, membrane push-rod 12, and guide 26, urged by the return spring 28, returns slowly to its initial position as and when the air contained in the chamber 18 passes back into the fore chamber 14 through the ball throttling device 2t)- 21, the velocity of flow of air through this device being adjustable, as has previously been seen, by moving the adjusting screw 7 in its support 6.

As the rod 26 moves from the rear to the front, it pushes the actuator 33 in the same direction. For a particular position of this latter the snap action switch II abruptly cuts contact by passing from the position illustrated in FIGURE 5 to that illustrated in FIGURE 6.

The system is again in its initial position and another cycle of operation can now take place.

In accordance with one feature of the present invention which has already been mentioned, the timer-snap action switch device can be controlled by a relay or electromagnetic contactor instead of being manually controlled.

In order to do this, the assembly constituted by the contact casing 9 and its cover 10, the operating body 1, its two

membranes

2 and 3, the screen 8 and the rear cover 4, the whole assembled by hollow longitudinal rivets I3, is attached in this case onto a support piece55 itself mounted on the base-plate of a contactor or electromagnetic relay designated by the general reference 56 in FIGURES 10 and 11. The timing device can easily be fixed onto the support 55 by means of two screws passing through two of the hollow assembly rivets 13.

In order to clarify the drawing, the relay 56 has been diagrammatically illustrated by its winding 57 and its armature having, in the usual manner, a fixed part 58 and a mobile part 59, this latter being constantly biased in the direction F1 by any resilient return system (not illustrated) In the case under discussion, the control of the actuator, whose extremity 33A appears in FIGURES 10 and 11, can advantageously be operated by means of an external lateral forked member 60 which is mounted to slide by means of two

rods

61, 62 passing through two of the hollow assembly rivets 13 and which has an extension 63 acting on the said actuator 33A. A return spring 64 constantly biases the control forked member 60 in the direction of arrow F1.

The said forked member 60 has on its free face at least one projection 65 against which a complementary projection 66 of the mobile armature 59 of the relay bears when the said relay is operated.

It is evident that the relay armature can, indiiferently, have either a rectilinear stroke parallel to that of the membrane push-rod (as is the case for FIGURES 10 and 11), or an angular stroke. In fact, without exceeding the scope of the present invention, it suffices merely to adapt the shape of

projections

65 and 66 to ensure the drive of the forked member 60 by the mobile armature 59.

In the set-up illustrated in FIGURE 10, timing occurs on the actuation of the relay.

It will be seen that when the said relay is not energised the different mobile members are located in respective positions as illustrated in FIGURE 10 and in particular the members of the timing device are located in the respective positions as illustrated in FIGURE 1.

As soon as the relay is energised the mobile armature 59 moves into the direction of arrow F2, driving the lateral forked member 60 in the same direction. The extension 63 frees the extremity 33A of the actuator, whereupon the timing device operates in the manner which has been described with reference to FIGURE 1.

When the relay is tie-energised, the return springs retract the different mobile members to their respective positions illustrated in FIGURE 10, the snap action switch 11 being retracted to the position illustrated in FIG- URE 1.

In accordance with a further feature of the present invention it is only necessary to turn end-for-end the timing device and its lateral control forked member 60 on its support 55 for the timing to take place this time on the cutting-off of the relay.

It will be seen that in this case (FIGURE 11) the mobile armature 59, when the relay is energised, drives the lateral forked member 60 in the direction of arrow F2. This forked member acts on the actuator 33A by the extension 63 and closes the snay action switch 11. When the relay is de-energized the mobile armature 59 returns to its initial position as in FIGURE 11, and it is only then that the timing device comes into action.

In order to be certain that the armature of relay 59 is completely closed before the actuator 33A of the snap action switch arrives at the end of its stroke, even in the case of careless assembly, and in particular with inverted timing following the cut-off of the relay (FIGURE 11), it is to be noted that the lateral forked member 60 acts 011 this actuator 33A through a leaf spring. This result can be obtained, for instance, as is illustrated in FIG- URE 12. The extension 63 has an orifice 67 disposed to face the extremity 33A of the actuator. On the outer surface of said extension 63 there is fixed, by means of one extremity, a leaf spring 68 whose other extremity bears a stud 69 which passes through the orifice 67 and can bear resiliently against actuator 33A when the relay is closed.

It is to be understood that the invention has only been described and illustrated purely by way of explanation and without any intention of limitation, and that any modifications of detail can be made therein conforming to its spirit without exceeding the scope of the said invention.

I claim:

1. A pneumatic timing apparatus comprising:

a first chamber,

a second chamber operatively connected to said first chamber,

membranes delimiting said chambers,

a first channel connecting said two chambers and adapted to enable fluid from said first chamber to be forced rapidly into said second chamber,

a second channel connecting said two chambers,

a throttling means operatively connected to said second channel adapted to enable fluid to return slowly from said second chamber into said first chamber,

a snap action switch assembly having a switch actuator,

a push member adjacent one of said membranes delimiting said first chamber and in a position to force that membrane into said chamber during operation of said push member,

guide means in operative alignment with said switch actuator,

a forked member engageable with said push member and having a slidable central push-rod located in operative alignment with said switch actuator,

('3 i as a first resilient means opposing the movement of said forked member against said push member, and a second resilient means opposing the movement of said central push-rod against said forked member,

said first resilient means possessing less opposing force than said second resilient means to the extent that said forked member conducts said push member to the end of its stroke against the said adjacent membrane before said central push-rod can move against said switch actuator thereby actuating said switch assembly.

2. The pneumatic timing apparatus of claim 1 further characterized by a section of a wall of said first chamber conforming substantially to the surface of application of said push member whereby said adjacent membrane is applied integrally onto its seating constituted by said section of a wall.

3. The pneumatic timing apparatus in accordance with claim 1 further characterized by the volume of said second chamber being larger than the volume of said first chamber, a casing enclosing said push member and said switch actuator, and pressure balancing conduits forming fluid passageways between said second chamber and said casing whereby the pressure within said second chamber and the pressure around said push member are equalized.

4. The pneumatic timing apparatus of claim 1 Where in said guide means engages said switch actuator during the return stroke with delaying eifect.

References Cited in the file of this patent UNITED STATES PATENTS 2,538,038 Ponstingl et al. Jan. 16, 1951 2,629,793 Ponstingl Feb. 24, 1953 2,662,594 Schaefer Dec. 15, 1953 2,855,481 Lindahl Oct. 7, 1958 2,866,862 Bachi Dec. 30, 1958 3,019,317 Gauvreau Jan. 30, 1962 3,037,101 Komatar et a1 May 29, 1962

Claims

1. A PNEUMATIC TIMING APPARATUS COMPRISING: A FIRST CHAMBER, A SECOND CHAMBER OPERATIVELY CONNECTED TO SAID FIRST CHAMBER, MEMBRANES DELIMITING SAID CHAMBERS, A FIRST CHANNEL CONNECTING SAID TWO CHAMBERS AND ADAPTED TO ENABLE FLUID FROM SAID FIRST CHAMBER TO BE FORCED RAPIDLY INTO SAID SECOND CHAMBER, A SECOND CHANNEL CONNECTING SAID TWO CHAMBERS, A THROTTLING MEANS OPERATIVELY CONNECTED TO SAID SECOND CHANNEL ADAPTED TO ENABLE FLUID TO RETURN SLOWLY FROM SAID SECOND CHAMBER INTO SAID FIRST CHAMBER, A SNAP ACTION SWITCH ASSEMBLY HAVING A SWITCH ACTUATOR, A PUSH MEMBER ADJACENT ONE OF SAID MEMBRANES DELIMITING SAID FIRST CHAMBER AND IN A POSITION TO FORCE THAT MEMBRANE INTO SAID CHAMBER DURING OPERATION OF SAID PUSH MEMBER, GUIDE MEANS IN OPERATIVE ALIGNMENT WITH SAID SWITCH ACTUATOR, A FORKED MEMBER ENGAGEABLE WITH SAID PUSH MEMBER AND HAVING A SLIDABLE CENTRAL PUSH-ROD LOCATED IN OPERATIVE ALIGNMENT WITH SAID SWITCH ACTUATOR, A FIRST RESILIENT MEANS OPPOSING THE MOVEMENT OF SAID FORKED MEMBER AGAINST SAID PUSH MEMBER, AND A SECOND RESILIENT MEANS OPPOSING THE MOVEMENT OF SAID CENTRAL PUSH-ROD AGAINST SAID FORKED MEMBER, SAID FIRST RESILIENT MEANS POSSESSING LESS OPPOSING FORCE THAN SAID SECOND RESILIENT MEANS TO THE EXTENT THAT SAID FORKED MEMBER CONDUCTS SAID PUSH MEMBER TO THE END OF ITS STROKE AGAINST THE SAID ADJACENT MEMBRANE BEFORE SAID CENTRAL PUSH-ROD CAN MOVE AGAINST SAID SWITCH ACTUATOR THEREBY ACTUATING SAID SWITCH ASSEMBLY.