US3440032A - Method and apparatus for making dimpled reed capsules - Google Patents

Description

A ril 22, 1969 B. c. COOK, JR.. ET AL 3,440,032

METHOD AND APPARATUS FOR MAKING DIMPLED REED CAPSULES Filed Aug. 16, 1955 Sheet .of 5

INVENTOR BATES C. COOK JR.

/ Rick- AZ M. ROZNYAK ATTY.

A ril 22, 1969 B. C.'COOK, JR; ET AL 3,440,032

METHOD AND APPARATUS FOR MAKING DIMPLED REED CAPSULES Sheet Filed Aug. 16, 1965 AMP-l SOLA SOLB

-FIG.3

INVENTOR BATES c. cooK JR.

R BY HARHD M ROV NYAK CAP-3 ERM-l D L3'F@ I I RM-Z I I ERM'3 A ril 22, 1969 B. c. COOK, JR.. A 3,

METHOD AND APPARATUS FOR MAKING DIMPLED REED CAPSULES Filed Aug. 16, 1965 Sheet 2 of 5 o O v CAP-I A AB-3L'- AB- 4 l AB- LAQ-IO I ll FIG.'4

. INVENTOR BATES C. COOK JR.

' B. c. COOK, JR..-

ME'IHOD AND APPARATUS FOR MAKING DIMPLED REED CAPSULES medm'. 1 .1965

ET AL- I 'April 22, '1969 Sheet 4 015 Einjomvniw Cum m INVENTOR BATES C. COOK JR. RICHAR .ROVNYAK ATTY.

Sum

A ril 22, 1969 B. c. COOK, JR., ET AL 3, 0,0

METHOD AND APFARATLS FOR MAKING DIMPLED REED CAPSULES Filed Aug. 16. 1965 Sheet 5 of 5 FIG.? FIGJO OP RP OP RP OP RP OP I for! [21 (c) FIG.8 F|G.|l

INVENTOR H6 5 BATES c. COOK JR'. FIG.3 FIG.4 VNYAK United States Patent 3,440,032 METHOD AND APPARATUS FOR MAKING DIMPLED REED CAPSULES Bates C. Cook, Jr., Chicago, and Richard M. Rovnyak,

Hanover Park, Ill., assignors to Automatic Electric Laboratories, Inc., Northlake, Ill., a corporation of Delaware Filed Aug. 16, 1965, Ser. No. 479,736 Int. Cl. C03b 23/12, 23/18 US. Cl. 65160 2 Claims ABSTRACT OF THE DISCLOSURE A dimple is placed in the glass envelope of a reed switch adjacent each reed contact to prevent stray magnetic fields from closing reed contacts which vibrate upon release. The process for forming the dimples is controlled by apparatus which simulates operation under stray magnetic field conditions and which continuously monitors the progress of dimple formation. The control apparatus includes circuits for operating a reed switch under adverse stray field conditions, control circuits for operating gas fueled torches heat the envelope and CRT displays for visually monitoring dimple formation.

This invention relates to glass encapsulated reed switches and more particularly to techniques for preventing malfunction of such switches due to vibrations of the reeds.

It has been observed that reed switches have a tendency to operate even at times when the magnetic field acting upon them is less than the prescribed just-operate field.

This occurs, for example, where stray magnetic fields which are normally not sufficient to effect closure of the reeds, are yet strong enough to reclose the reeds if they are vibrating on release. An instance of this kind has been found to exist in reed relay assemblies comprising both make and break contacts, where a permanent magnet or bias winding is used to keep the break contacts in 21 normally closed condition. However, regardless of the existence of such stray fields, vibration or chattering of the reeds is highly undesirable as it interferes with the proper control of the output circuits. It has been found that a dimple or dimples formed in the glass envelope in close proximity to the reed blades will dampen these vibrations so that they have no harmful effects.

Accordingly, it is an object of this invention to provide an improved reed switch which is substantially free of harmful vibrations; and, more particularly, one that will not operate falsely due to the action of stray magnetic fields or the like on its reed members.

Another object of this invention is to provide a new and improved process to manufacture substantially vibration free reed switches.

Still another object of this invention is to provide apparatus to control the creation of dimples or indents placed in the envelopes of reed switches which dampen vibrations occurring in their reed members.

In the embodiment of the invention described below, the dimples are formed in the glass envelope in a position such that a fiat portion of the reed contact blades opposite the contact surfaces will rest against them during the time the contacts are unoperated. When the reed contacts are in a closed position and then released, the dimples prevent the reed blades fro-m swinging past What would normally be their equilibrium position in a conventional undimpled reed capsule. Thus, the reed is dampened or stopped before beginning the first oscillation of its normal vibration cycle.

A feature of the process and apparatus according to the present embodiment is the application of a high tempera- 3,440,032 Patented Apr. 22, 1969 F ice ture source to a capsule at the points desired for location of a dimple, and the utilization of the difference in the atmospheric or surrounding pressure and the pressure existing in a standard reed capsule, which is usually less than atmospheric, to push in and balloon the softened glass against the reed blades to create symmetrical indents or dimples. Any external pressure which is greater than the internal pressure of the envelope is meant to be included within the scope of the aforementioned term atmospheric.

An important feature of the invention consists in that the production of the dimple or dimples is controlled, and preferably automatically controlled by electrically detecting, in a simulated operation of the reed switch, the vibrations of the reed or reeds as the dimple or dimples are formed.

Another feature of this invention is the detection of the dampening effect on a vibrating reed member of a dimple being formed in an envelope of a reed switch, by supplying alternate operate and reclosure pulses to a coil surrounding the reed switch as the dimple is being formed, and observing the cessation of the reclosure of the reeds due to the reclosure pulse as the dimple reaches its correct depth.

Still another feature of this invention is the detection of the dampening effect on a vibrating reed member of a dimple being formed in an envelope of a reed switch by supplying operate pulses periodically to a coil surrounding the reed switch as the dimple is being formed, and during the time no pulse is supplied, observing the voltage induced in the coil due to the vibrating reed until this vibration ceases and a predetermined amount of induced voltage is present.

Another feautre of this invention is apparatus which automatically controls the dimple depth by removing the source of heat creating the dimple when it has been found, through analysis by the detection methods mentioned above, that dampening of the vibrations of the reeds has occurred.

Other objects and features of the invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a diagram illustrating the apparatus used to form indentations or dimples in reed switch envelopes FIGS. 6-l1 are graphical illustrations to aid the reader in the understanding of the invention; and

FIG. 12 is a diagram showing the manner in which FIGS. 3, 4 and 5 are oriented.

Looking at FIG. 1, carriage 11 is a movable device which is part of the mechanical apparatus disclosed in application Reed Switch Dimpling Machine, W. E. Neese filed on even date, Ser. No. 479,911, filed Aug. 16, 1965, assigned to the same assignee as the present invention, to position reed switch within split coil 314 and 317. Control 13 is for supervising the operation of torches TOA and TOB which heat portions of the envelope of reed switch 10 to form the dimples by the pressure dilference within and outside of the envelope. Electromagnets 312 and 313 are for locking carriage 11 into position X or Y before the dimple forming operation begins.

FIG. 2 shows a dimpled reed switch 22 comprising envelope 23, reed members and 21, and dimples 24 and 25 conforming to the fiat surfaces of the reeds 20 and 21 to dampen vibrations thereof.

FIGS. 3, 4 and 5 show the apparatus used to control the formation of a dimple in the envelope. Generally, contacts 309, 310, or 308, 311, electromagnets 312 or 313, and relays ERM, D, LR, ST and S begin the process. Oscillator 320 and relays P and G are used to pulse split coil 314, 317. In a preferred embodiment of the invention, a Hewlett Packard Type 200 J audio oscillator is used with its frequency set at 33 c.p.s. Relay AB in conjunction with relays A and B regulates the formation of the dimples by controlling both solenoids SOLA and SOLB to move the torches TOA and TOB, shown in FIG. 1, into position to heat the reed switch envelope, and the pulsing means mentioned above.

The torches used in the above mentioned embodiment are #23 hypodermic needles having their tips ground, and are fueled by two Henes Model S gas generators supplying a mixture of H and O and booster units which entrain alcohol vapor in the gas to increase the Btu. output of the torches. One gas supply is set at about 0.7 p.s.i. and the other at about 0.6 p.s.i.

The solenoids, SOLA and SOLB used to drive the torches TOA and TOB into position, include solenoid controlled tour- way air valves 14 and 15.

Oscilloscopes 316, the drive scope, 315, the monitor scope, and limiter circuit LIM comprise a detecting means which determines When the dimples being formed have reached a depth to sufiiciently dampen the vibrations set up in the reeds by means of the pulsating coil. Scope 316 is connected to relay C which sustains the process until the detecting means finds that the dimple has reached a correct depth.

The Oscilloscopes preferred for usein the above mentioned embodiment are a Tektronix Type 535 with a Type Z pre-amplifier for the monitor scope 315 because of its high dynamic scale, and a Type 532-37 Tektronix oscilloscope with a Type O operational amplifier having three functional circuits; a conventional output to the CRT vertical and two independent operational amplifiers for the drive scope 316.

The scopes 315, 316 are interconnected by a limiter circuit LIM including a pair of oppositely conducting diodes D3, D4, used in a Zener capacity to limit the voltage across the pair to less than one volt maximum in either direction.

A circuit shown in FIG. 5, comprising relay TR and its contacts, TR-S and TR-6, transistor (unijunction) 510, and various resistances, is energized at the start of each dimple making process to see that the process does not continue longer than a predetermined length of time. Another circuit comprising peg-count meter 511, the TR relay and its contacts TR-l TR-4 counts the number of reed switches which have had their envelopes dimpled. Still another circuit comprising relay R and its contacts R-1R-9, operated peg-count meter 512 which counts the reed switches that have been rejected during the process and buzzer 513 which sounds when a rejection occurs. If a rejection does occur, due to the process taking an abnormally long time or for some other reason, the cycle is ended by relay R and the circuit must be manually reset at switch SW-2 to begin the cycle again.

FIG. 6 shows a wave form appearing on scope 316, the drive scope, which displays normal reed contact reclosure while making the first dimple in the reed switch envelope.

FIG. 7 shows a wave form appearing on scope 315, the monitor scope, While the second dimple is being formed which shows the normal voltage induced in the coil by vibration of a reed member, located in an undimpled envelope if the other reed member has been dampened by a well seated first dimple.

FIG. 8 displays a gated signal from monitor scopes 315 vertical output into drive scope 316.

FIG. 9, shows monitor scope 315 trace of an abnormal voltage induced in the split coil 314, 317.

FIG. 10 illustrates a trace on monitor scope 315 showing normal coil voltage of an adequately dimpled capsule.

FIG. 11 shows the pulsing supplied to the coil 314, 317, and to gated amplifier AMP-2. Trace A shows the operate pulses OP and reclosure pulses RP supplied to split coil 314, 317 during the formation of the first dimple.

Time T denotes that the reeds separate 0.15 ms. after the operate pulse OP ends. Time T denotes that the reclosure RP pulse starts about 0.5 ms. after the operate pulse OP ends, although it is not necessary time T indicates that the reclosure pulse RP ends 0.5 ms. before the beginning of the next operate pulse OP.

Traces B and C show tht the gating pulse DP occurs an interval T after the ending of operate pulse OP during the formation of the second dimple.

A more detailed description of the dimple making process can be illustrated by looking at FIG. 1. The dimple operation begins by placing a reed switch 10 on carriage 11.

The carriage is moved to position X or Y, where reed switch 10 is placed within coil 314 and 317 and either electromagnet 1 or 2 is energized as contacts 4 and 5 or 6 and 7 at position X or Y, respectively, are closed by portion 3 or 8 on carriage 11, to lock the carriage into position, At this time, control 13 energizes solenoid SOLA to operate piston PIA to move torch TOA into position to heat a portion of the reed switch envelope, beginning the first dimple cycle. The principle used to form and control the first dimple is to apply the torch TOA and at the same time supply alternate operate and reclosure pulses to coil 314, 317. The reclosure pulse is of less magnitude than the operate pulse, but is of a sufficient strength to cause a reclosure of the reed contacts when applied immediately after the operate pulse. This is due to the natural vibration of the reeds following their release after the operate pulse. As torch TOA begins to soften a portion of the envelope of reed switch 10, the atmospheric or surrounding pressure, which is greater than the pressure within the envelope R i.e. approximately 0.6 atmospheres, begins to form the first dimple. As the dimple forms the heated portion of the envelope moves inward until it touches and conforms to the flat surface of the pertinent reed blade 17 with sufficient force to dampen its natural vibration. As soon as the dimple dampens the normal vibration, blade 17 no longer swings close enough to the other blade 16 to allow the reclosure during the application of a reclosure pulse and automatically withdraws torch TOA.

After the first dimple is completed, control 13 immediately and automatically applies torch TOB, in the same manner as torch TOA, to begin forming the second dimple. Since the reclosure pulse used on the first dimple will not operate the reed contacts because the blade 17 associated with the first dimple has been dampened, a different sensing of the completion of the second dimple is used. This time an operate pulse is applied to coil 314, 317 and then immediately thereafter the voltage induced by the remanent magnetism of the single vibrating reed blade 16 within coil 314, 317 is detected. As the second dimple moves inward and begins to dampen the vibration of reed blade 16, the magnitude of the induced voltage begins to drop oil. When the dimple dampens the vibration sufliciently, and the induced voltage drops to a predetermined level, control B withdraws torch TOB. When both dimples have been placed into the envelope of reed switch 10, carriage 11 is moved out of its position X or Y and the reed switch is manually removed. Then the process can begin again with another undimpled, reed switch being placed into the carriage.

A detailed description of FIGS. 3, 4 and 5 (control 13 of FIG. 1) will make it clear just how the control apparatus used to supervise the formation of the dimples, operates.

For the circuit 13 to be utilized poweris supplied from the DC. source DCS to power bus PB by way of normally closed switch SW-Z, relay contacts R-G, R-7 and switch SW-l. Tracing the bus PB further (through FIG. 4) lamp L3 is lighted to indicate that power is available to the control circuitry. In a similar fashion power is supplied to light lamp L4 to indicate that solenoid power is available to the control circuitry. Solenoid power is fed to contact LR-1 via SW-3, SW-1 and solenoid power bus SPB.

As carriage 11, FIG. 1, is positioned in position X or Y, spring contacts 309, 310 or 308, 311 are closed. When either of those sets of contacts are closed, a ground is supplied by way of the winding of electrical magnet 312 'or 313, 'to operate relay ERM. Contacts ERM-1 and ERM-Z or ERM-2 and ERM-3, in turn supply a ground to pulse stretching relay D to operate it, and contacts ERM-4 and ERM-5 or ERM5 and ERM-6 operate relay LR. As relay -D operates, it sends a ground pulse to momentarily operate relay ST via contacts D1 and D-2. Relay ST in turn sends battery via contacts ST-3 and ST-4 to operate relay S. The operation of relay S supplies battery via contacts S5 and S-6 to operate relay TR to start the timing circuit. Relay AB operates by means of battery and ground supplied by relay ST by contacts ST-3 and ST-4 and ST-S and ST-6, respectively, and locks up by its contacts AB-10, AB-11 and contacts 8-7, 8-8 and C-1, C-2 before relay S releases. At this time, relay AB supplies the power necessary, via contacts AB-12 and AB-13 to operate solenoid SOLA to in turn bring torch TOA close to the reed switch envelope to heat a portion thereof and to begin to form the first dimple.

Simultaneously, oscillator 320, pulses relay P which in turn supplies alternate operate OP and reclosure pulses RP (FIG. 11, trace A) to split coil 314, 317 (e.g. operate pulse via contacts P2 and P-3, RES-1, FC, winding 314, 317 to ground, reclosure pulse via contacts P-1 and P2, AB-8 and AB9, diode D1, RES2 and connection FC). As previously explained, the reclosure pulses cause contacts 16 and 17 of the reed switch to close as long as the vibrations caused by the operate pulse have not been dampened by the oncoming dimple. Due to the closing of the reed contacts 16 and -17 upon impression of the reclosure pulse, relay C is held operated by CAP-3 to sustain the cycle. Relay C is operated via power from PB through contacts P1 and P-2, AB8 and AB9, RES-3 GC, reed contacts 16 and 17, BC, AB-15 and AB-16 and AMP-1 of drive scope 316 (see normal reed contact reclosure trace, FIG. 6).

Relay C in turn keeps holding power on relay S via contacts C-1 and C-2 and S-7 and 8-8. When reed contacts 16 and 17 no longer reclose due to the dampening effect of the dimple, the aforementioned path opens, the C relay drops out and the S relay is released, ending the cycle for the formation of the first dimple. When the S relay releases, contacts S-9 and 8-10 open and remove power to the torch TOA, moving it away from the envelope. Relay LR is released via contacts S-1 and S2, and relay AB is released by the opening of contacts S-7 and S8.

Relay S is now operated again via relay C because of relay P, which is still being pulsed by oscillator 320 as will be explained below. Upon operating relay S, relay LR is again operated over a previously mentioned circuit. However, relay AB remains unoperated.

Torch TOB is now brought near to the envelope of the reed switch getting power supplied to solenoid SOLB via contacts S9 and S- and AB-13 and AB-14. To form the second dimple, as mentioned previously, a different technique is employed.

This time as relay P is pulsed, it in turn pulses coil 314, 317 with operating pulses OP (FIG. 11, trace B) via path contacts P2 and P-3, RES-1, and FC, and the undampened reed blade begins to vibrate. The vibrating reed induces a voltage (FIG. 7) in the split coil between the pulses via the aforementioned path. This -voltage, due to the vibrating reed within coil 314, 317, is detected by AMP-4 in monitor scope 315, and the output 6 of 315 is fed through limiter circuit LIM into drive scope 316.

Simultaneously relay P sends a pulse via contacts P-1 and P-2 and AB-7 and AB-8 to pulse relay G, which provides delayed pulse DP, FIG. 11, trace C, via its contacts G1 and G2 and RES4, to gate the limiter LIM output through AMP2. This in turn is fed through AMP-3 (see FIG. 8), and by way of AB-16 and AB-17 is inverted to AMP-1, to operate relay C. When the dimple being formed sufiiciently dampens the vibrating reed, so the induced voltage attains a predetermined level, relay C is no longer pulsed. It once again drops out, opening the circuit to relay S, withdrawing torch TOB.

Since the output from drive scope 315, in forming both dimples, may not be immediately effective to pulse relay C, capacitor CAPI is connected to contacts AB1 and AB-Z, and is charged upon operating switch SW-l, via PB. If relay C does not operate to close its contacts C1 and C-2 to hold relay S operate, CAP-1 discharges upon operation of relay AB, via contacts AB-2 and AB-3 to operate relay A which sends, via contacts A-1 and A-2, battery to relay S to operate it, until relay C is operated. Likewise, CAP2 has a similar function as CAPI in operating, relay S during the time between forming the 1st and second dimple, via contacts AB-4 and AB-S to operate relay B which sends battery to relay S via contacts B1 and B2.

As mentioned previously, when the TR relay was 0P- erated, a timing circuit began to see that the process of forming both dimples did not take longer than a prede termined length of time. During the interim when relay S was released, its contacts S5 and 8-6, which keep relay TR operated, were opened, but since relay TR has across it a slugging diode D-2, it is held operated.

When relay TR was first operated, it supplied battery by contacts TR-1 and TRZ to operate counter 511. Ground is also supplied by way of contacts TR-3 and TR-4 to light lamp L1. Battery is supplied via contacts TR-S and TR6, RES5, RES6, for charging CAP-4. If the formation of the dimples is sufiiciently long to allow CAP-4 to charge to a predetermined value, transistor 510 will operate and supply an enabling pulse to the gate of silicon controlled rectifier 520.

When silicon controlled rectifier 520 conducts, ground is supplied therethrough to operate relay R which has power connected to its other side via contacts S-3 and S4 and SW-Z. When relay R operates, contacts R1 and R2, supply power to operate buzzer 513, contacts R3 and R4 supply holding power for relay R, contacts R5 and R6 close, placing power on reject counter contacts R8 and R9, light lamp L2, and contacts R6 and R7 open, removing power from PB, immediately ending the cycle at this point.

Manual operation of SW-2, resets relay R to an unoperated condition so that the dimpling cycle may begin' anew.

Although automatic operation is preferred in the formation of the dimples, the process may be performed with detection being made by observing the monitor scope as the torch heats the envelope and then by manually removing the torch when the scope trace indicates that the dimple has damped the vibrations in the reeds. The detection could also be made visually through a microscope focused on the portion of the envelope being heated by the torch, and removal of the torch effected when the dimple was observed to be of a proper depth.

It will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broadest aspects and therefore, the aim in the appended claims is to cover all such changes and modifications as in the true spirit and scope of this invention.

What is claimed is:

1. Apparatus for forming an indentation in an evacuated envelope having a plurality of spring contacts therein said apparatus comprising: coil means; means to position said envelope adjacent said coil means; a source of heat; switch means operated by said envelope positioning means; means operated by said switch means and including means for energizing said coil means to cause at least one of said spring contacts to vibrate and means to position said heat source adjacent an area of said envelope near said one contact for heating said area to a plastic state allowing the pressure difference due to the evacuated condition of said envelope to form an indentation therein, the vibrations being dampened by said indentation; and vibration detecting means coupled to said one contact and effective after said vibrations have been dampened to a predetermined level to operate said heat source positioning means to remove said heat source from said envelope.

2. Apparatus for forming a dimple in an evacuated envelope having a pair of reed contacts therein, said apparatus comprising: a heating means to heat a portion of said envelope to a plastic state so that the difference in air pressure will form a dimple thereat; means to vibrate at least one of said reed contacts; vibration detecting means coupled to said contact; and means operated by said detecting means after said vibrations have been reduced to a predetermined level due to the dampening effect of said dimple to remove the heat from said portion when the vibrations are dampened to said predetermined level.

References Cited DONALL H. SYLVESTER, Primary Examiner.

JOHN H. HARMAN, Assistant Examiner.

US. Cl. X.R.

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