US2864920A - High speed switch mechanism - Google Patents

Description

W. HOTINE HIGH SPEED SWITCH MECHANISM Dec. 16, 1958 2 Sheets-Sheet 2 Filed Oct. 20, 1954 w R n mi Y m r, .T w w W United States Patent HIGH SPEED SWITCH MECHANISM William Hotine, Bayville, N. Y., assignor of one-third to George Trad, Asbury Park, N.

Application October 20, 1954, Serial No. 463,356

12 Claims. (Cl. 200-152) This invention relates to high speed switching mechanisms and, more particularly to switches employing liquid mercury as the electrical make and break element.

Presently known high speed switch mechanisms -employ a spring loaded member to effect the make and break of an electrical contact. Such mechanical switches are relatively large, lack long operative life, and are subject to frequent failures. Another disadvantage of present switch mechanisms of this type, is the tendency of chatter or bounce at the contacts. These characteristics are particularly undesirable in the type of high speed switch,

commonly called a chopper, used to convert direct current to alternating current.

In a chopper it is most desirable that the output wave pattern be symmetrical and free of spikes, which are caused by contact chatter.

Accordingly, it is one of the objects of this invention to provide a high speed switching mechanism wherein electrical contact is made without chatter of the contact elements.

An object of the present invention is to provide a switch mechanism that can be initially adjusted to produce an unvarying duty cycle and which adjustment will be maintained for the operative life of the switch.

Another object of this invention is to provide a high speed switch capable of operating at higher frequencies than presently known switches.

A further object of this invention is to provide a switch which, when used as a chopper, will produce a symmetrical square wave alternating current free of spikes.

A still further object of the present invention is to provide a switch free from mechanical failure thus insuring a long operative life.

A feature of the present invention is the simple compact construction of the switch.

Another feature of this invention is the absence of movable mechanical parts within the switch.

A further feature of the present invention is its adaptability for use as a high speed relay without modification.

A still further feature of the invention is the use of a mercury globule as the electrical make and break element within the switch.

Another feature of the present invention is the structure of the constrictive cavity in which the mercury is confined.

The invention consists of the construction, combination and arrangement of parts, as herein illustrated, described and claimed.

In the accompanying drawings, forming a part hereof are illustrated four forms of embodiment of the invention, in which drawings similar reference characters designate corresponding parts, and in which:

Figure l is an end elevational view of a complete embodiment of a high speed switch mechanism according to this invention.

Figure 2 is a view in section taken on line 2-2 of Figure 1 looking in the direction of the arrows.

2,864,920 Patented Dec. 16, 1958 Figure- 3 is a longitudinal central section of a second embodiment of the present invention.

Figure 4 is a fragmentary section similar to Figures 2 and 3 showing a third embodiment of this invention.

Figure 5 is a greatly enlarged vertical section, taken through a fourth embodiment of the present invention.

Figure 6 is a vertical section greatly enlarged, taken through one set of contact members of the switch shown in Figure 5, before the casting of the dielectric block the'rearound.

Referring to the drawings, and specifically to Figures 1 and 2, 10 designates a preferred switch actuating mechanism which comprises a modified dynamic loud speaker.

The usual cone is removed from the diaphragm 12 which is secured over the end of the speaker housing 11. Within a central opening 12*? in the diaphragm 12 is fastened a cylinder 13 which extends rearwardly into the speaker housing 11. A permanent magnet 14, mounted to the rear wall 15 of the speaker housing 11, projects a short distance into the cylinder 13. Around the cylinder 13 and between the pole members 16 is a coil 17. The input and out-put electrical leads of the coil 17 are indicated at 18 and 19.

The switch actuating mechanism, above described, is one form of switch actuator which may be employed to operate the switch hereinafter described. It is not essential that the specific actuating mechanism shown he used since it is within the purview of this invention that any other suitable motor means be employed.

Referring again to Figures 1 and 2, two support brackets cure the block 23 to support brackets 20 are received in two spaced holes 64 transverse of the block 23.

The block 23 is provided with two large tapped holes 24 and24 normally disposed with respect to the face ofthe diaphragm 12. Axially communicating with each of the holes 24 and 24 are two smaller diameter tapped holes 25 and 25 which are adapted to receive therein: contact screws 29 and 29 Into each of the large holes.

24 and 24 are threaded contact screws 26 and 26. Each of the screws 26 and 26 are provided at their inner ends with a depression or well 28. The purpose of these.

wells 28 will be hereinafter more fully explained.

Within each of the two cavities 30 formed between the contact screws 26 and 29, 26 and 29*, there is placed a globule of mercury 31. The drops of mercury 31 are of a size which will not fill completely the cavities 30.

As the wells 28 pro-vide a socket into which part of the globule of mercury 31 is received, the ends of each pair of contact screws 26 and 29, 26 and 29 may be brought closer together. reduction to be made in the size of the cavity 30. An other advantage of the constricted cavity is the elimnation of contact bounce or chatter. In the operation of the switch 22, the mercury globules 31 never fully leave the wells 28. The contacts between the globules of mercury 31 and the contact screws 26 and 26 is maintained by the wells 28, thereby eliminating the possibility of.

contact break between the screws 26 and 26 and the globule of mercury 31.

Contact plates or lugs 32, are slipped upon each of the contact screws 26, 26 29, and 29 Each of the contact screws 26, 26 29 and 29 is provided with -a The wells 28 thus permit a ts thecontact lugs'. 32 against ,the block 23. Each of the contact lugs 32 is adapted, to have secured thereto an electrical lead indicated at 34, 34 34 and 34, in Figure 2.

.tln'operatingjt-he above .described switch mechanism, alternating or intermittent-currentis supplied to the coil 17. through leads 18 and-19. The magnetic field created aroundttheecoil '17, by the passage of the current reacts with themagnetiofieldofithe permanent magnet 14 to alternatelyattract. and repelcylinder 13. The switch 22 whichisymounted upon the cylinder 13 is thus caused to .move axially '10. and from the actuator 10. The amplitude and frieqllency of the vibration of the switch 22 by the action of the actuator is a funct on of the amplitude and-frequency of the applied'voltage through the-coil 17.

The, ,drops, of mercury-31, are small enough to main taint-a globularzshapeiat all timesdue to their surface tension. 'When.,'the switch .is at rest, surface tension of thezitmercury'will keep the mercury drops 31 substantiallywithin .the. wells 28 and out of contact with the endszof the contact . screws 29 and 29 The surface tension .ofthe mercury is sufficient to prevent the flow of,..mer.cury, into the restricted openings formed by the junctureof holes v24 and 25, 24 and 25*. This surface tension is great-enough to resist the pull of gravity regardless of the axial position of the switch assembly and insuresathat-the mercury will not flow into the holes 25 and-.25. Therefore, the switch will operate without beingsteffected by. the gravitational pull thereon. With the switch 22 at rest or in a neutral position, the two circuits through leads 34, 34 34 and 34, are open.

Upon a sudden motion of the switch 22 in the directionof the coil 17, the center of mass of the mercury drops 31 remain stationary due to their inertia of rest. Themercury' drops 31, in the cavity between contacts'n26 andv 29 is forced into the constrictive opening of the hole 25 and contacts the end of the screw 29. This contact completes the circuit through leads 34 and-34 At the same time the mercury globule 31, in the cavity between screws 26 and 29 tends to fiatten against the contact screw 26. The flittening action insuresthat the circuit through lea-ds 34 and 34 is cpen. When the switch 22 is thrust away from the actuator 10' {to the left in Figure 2) the previously flattened drop of mercury 31 is forced into contact with screw 29 and closes the circuit through leads 34 and 34*. At the same moment the mercury globule 31, which previously closed the circuit through leads 34 and 34 i forced against screw 29 thereby breaking the circuit.

'As the mercury globules 31 substantially fill the cavities 30,- no contact chatter or bounce results when the mercury drops make contact with the screws 29 and 29*. This feature,'when the switch is employed as a chopper, produces a square wave alternating current wh'ch is free of -spikes.

"The use of two adjustable elements in switch 22 results in a device which can be exactly adjusted to 100% to produce a duty cycle with exactly equal dwell in each circuit. This adjustment is made by turning either one,

two, three or all of the contact screws 26, 26 29 or 29 in or out of the block 23. In this manner the opening time ofone c rcuit may be adjusted to coincide with the closing time of the other circuit. Once the adjustments have been made, the contact screws 26, 26 29 and 29 arelocked in position by the lock nuts 33.

In' Figure 3 there is shown a second embodiment of this invention employing a single globule of mercury 31. "The same motor or actuating means 10 may be used as shown in the first embodiment, with the exception that the means for mounting the switch 46 to the actuator 10 has been modified slightly, as will hereinafter be-apparent.

The switch 35 comprises a dielectric housing 36 which hasa body portion 38 and integral therewith two opvided in the body portion 38 adapted to receive a globule of mercury 31. Two bores and 40* are provided in the extended portions 37. The bores 40 and 40 are in an axial alignment and each communicates with the cavity 39. Receivable within each of the bores 40 and 40 is a contact pin 41, and 41 respect'vely. A third contact pin 43 is inserted into the cavity 39 by means of a bore 42.

In assembling the switch 35, the pins 41, 41 and 43 are inserted within their respective bores 40, 40 and 42. A globule of mercury 31 is then placed within the cavity 39. The open end of the cavity .39 is sealed by a plug 44. The shank of the plug 44 extends a sufficient distance into the bore 39 to define the proper cavity size in which the mercury is housed.

The cavity 39, bores 40, 40 and 42 are chamfered slightly at their outer ends so as to provide a receiving surface for an adhesive material, such as the cement indicated at 45. The pins 41 and 41 and the plug 44 are inserted and sealed at the housing 36, by the cement at 45.

.As the contact pin 43 extends into the globule of mercury'31, adjustment of the pin within the cavity 42-will change the volumetric displacement of the mercury-31. By movement of the pin 43, the switch 35 may be adjusted to provide a 1.00% duty cycle with exactly equal dwell in each circuit. When the switch is finally adjusted the-pin 43is sealed at the housing 36.

The cylinder 13 of the actuator 10 has been adapted to connect with the housing 36 of the switch 35. The cylinder 13 for example, may be necked down to the size of the switch body. The switch 35 is mounted to the cylinder by inserting one of the extended portions 37 into the narrow neck 47 of the cylinder 13. The switch-35 may be fastened to the neck portion 47 by cement or by any other suitable means.

The ends of the contact pins 41, 41 and '43 are providzd with terminals 48 to which are connected electrical leads 49, 49 and 49 Theswitch 35 in Figure 3, is shown in an operative position at the moment of its outward thrust from coil 17. In this phase of operation, the circuit through leads 49 and49 is closed. Upon a movement back toward the actuator lit, the contact is broken at pin 41 and the mercury globule 31 contacts pin 41thereby completing the circuit through leads 49 and 49. Due to the inertia of rest of the mercury 'blobule 31, the cavity in which it is located moves relative to the globule 31 to make and break the circuits.

The second embodiment of the presentinvention shown in Figure 3 has all of the desirable characteristics of the first embodiment; namely, freedom from contact bounce or chatter, ease of adjustment, long operativeflifeand uniform operation. This switch 35 is less expensive to manufacture and has the further advantage of only three contacts instead of the four shown in the first embodiment.

In Figure 4 there is shown a third embodiment of the present invention. The switch Sll illustratedin Figure 4 is shown in an operative position thrust outward of the actuator mechanism (not shown). The switch 50 comprises a substantially T-shaped dielectric block .51 having a longitudinally tapped bore 52. Contact screws 53 and 53 are inserted from each end of the hole 52. A bore 54 is provided in the leg of the block 51, which bore communicates with the tapped bore 52. The bore 54 is threaded to a point short of the bore 52, at which point, it is constricted as shown at'55. A contact screw 56 is threadably receivable within the bore 54. The contactscrew 56 has a reduced end portion 57 adapted to extend through the constricted portion -.of the bore 54 and into the globule of mercury 31. v

The switch 50 is secured directly to the actuator-diaphragm 12 by cement or other suitable means, as indicated at 58.

Electrical contact leads 59, 59 and 59 are connected to the contact plates or lugs 32 which are passed over the screws 53, 53 and 56. The lugs 32 are held in place against the switch housing 51 by lock nuts 33. The lock nuts 33 also serve to hold the adjusted position of the contact screws 53, 53 and 56.

As in the other embodiments of this invention, the

mercury drop 31 is positioned in the restrictive cavity formed by'the end of the screws 53, 53 and no contact chatter is present. This switch is similar to the switch 46 shown in Figure 2, but is capable of a variety of precise settings through the adjustment of the three contacts 53, 53 and 56.

The use of mercury globules 31, in the forms of the invention herein disclosed, produces a switch having a long operative life. The mercury globules 31 being liquid spheres form resilient cushions and contact is made without wear to the contact screws or pins. tion may be eliminated in the switch mechanism by filling the cavities with an inert gas.

Referring to Figure 5, there is shown a fourth embodiment of the present invention, employing any preferred activating mechanism, such as the modified dynamic loud speaker previously described. The switch members of this embodiment comprise a dielectric block 61 which is molded about opposed contact members 62, 63.

The manner in which the molding is accomplished may best be understood by reference to Figure 6. The contact member 63 is vertically disposed within a jig (not shown) with its central cavity 64 located at the top thereof. A globule of mercury 31 is then placed in the opening 65 of the contact member 63. The surface tension of the mercury 31 is such that it retains its spherical shape due to the minute size of the opening 65 in the cavity 64.

The contact member 62 is then placed in the jig and the end thereof brought into contact with the globule of mercury 31. A suitable dielectric material 61, such as has been previously described is then molded around the contacts 62, 63 and the globule of mercury 31, so as to seal the entire assembly therein.

The interior of the switch is thus hermetically sealed and becomes shielded from the efiects of outside air, moisture, and the like. After the dielectric material 61, hardens, the structure has the appearance of the switch members 60 shown in Figure 5. The contacts 62, 63, extend from the dielectric blocks 60, so as to receive the ends of electrical leads 66, 67 and 68 thereon.

. The dielectric block 61 may then be secured to the diaphragm 12 of the dynamic loud speaker assembly, or other actuating means by any suitable device such as cement.

In the embodiment shown in Figures 5 and 6, the cavity 64 is provided with a bottom recess 69 which enables the mercury 31 to invade the cavity 64 and lose electrical contact with the contact member 62 when the switch is thrust in the direction of said contact 62.

In Figure 5 the switch mechanism has been thrust to the left. As a result, the globule of mercury 31, which remains stationary due to its high mass, is contacted by the contact element 62 in the upper switch member, while the contact member 62 in the lower switch member is withdrawn from the mercury 31. When the switch assembly is thrust to the right, the upper globule of mercury 31 will be forced into the cavity 64, and the lower globule of mercury will come in contact with the lower contact member 62*.

The electrodes or contacts 62 in the block 61 may be suitably adjusted as shown in Figure 5 by sliding them out' a desired distance while the dielectric material is still soft or by employing a threaded contact as shown Oxidain Figures 2 and 4 and backing out the contacts a clesired number of turns.

The advantage of molding the dielectric block 60 about the globule of mercury 31 and the contact members 62, 63, is that in addition to hermetically sealing the interior of the switch element, the cavity about the mercury is formed with an absolutely smooth surface free from burrs, scratches or other obstructions, which would interfere with the smooth operation of the switch.

The switches as herein described may be employed as high speed relays, by supplying the coil 17 of the actuator 10 with pulsating direct current to impart intermittent kicks or thrusts to the switch. This relay action would deflect the switch causing one circuit to close and a reversal of the pulse would close another circuit.

It is readily apparent from the foregoing disclosure that a high speed switch has been produced which can be operated at higher frequencies than presently known switches. These switches are subject to little or no wear and have a long operational life. When the switch is employed as a chopper it produces a wave output pattern free of spikes, perfectly symmetrical and unvarying over an indefinite period of operation. Further, the switch disclosed may be used as a high speed relay without modification.

Having thus fully described the invention, what is claimed as new and desired to be secured by Letters Patent of the United States, is:

l. A high speed switch mechanism comprising, a dielectric block having a cavity therein, a globule of mercury received in said cavity, a plurality of electrical contact members having one end thereof within said cavity and the opposite end extending outside of the said block at least one of said contacts forming with the blocks a mercury retaining well therein, a switch actuating means secured to said block to induce a high speed reciprocal motion of the block and contacts, with reference to the globule of mercury, to alternately make and break the electrical contact between certain of the said contact members.

2. A high speed switch mechanism comprising, a di electric block having a cavity therein, a globule of mercury received in said cavity, a plurality of adjustable electrical'contact members having one end thereof Within said cavity and the opposite end extending outside of the said block at least one of said contacts forming with the blocks a mercury retaining well therein, means for locking said contact members in their adjusted positions, a switch actuating means secured to said block to induce a high speed reciprocal motion of the block and contacts, with reference to the globule of mercury, to alternately make and break the electrical contact between certain of the said contact members.

3. A high speed switch mechanism comprising, a dielectric block having a cavity therein, a globule of mercury received in said cavity, a plurality of threadably adjustable electrical contact screws having one end thereof within said cavity and the opposite end extending outside of the said block at least one of said contacts forming with the blocks a mercury retaining well therein, means for locking said contact members in their adjusted positions, a switch actuating means secured to said block to induce a high speed reciprocal motion of the block and contacts, with reference to the globule of mercury, to alternately make and break the electrical contact between certain of the said contact members.

4. A high speed switch mechanism comprising, a dielectric block having a plurality of opposed longitudinal bores, said bores being in'communication with each other to provide spaced paths through the block, a contact member adjustably receivable in each of the bores one of said contacts being recessed within the bore to form a mercury retaining well therein, a globule of mercury received in the bores between each opposed pair of contact members, a means for locking said contact members in their adjusted, positions, electrical leads-secured to eachof said contact members, a switch actuating means. secured' to: sardblock toainduce a high speed reciprocal motion'of thelblock. and contacts with reference to theglobule of mercury, to alternately make and break electrical con tact between each pair ofsaid contact members.

5. Ahigh. speed switch, mechanism comprising, a dielectric block having .a plurality of opposed longitudinal tapped bores, said bores being in communication with each other to provide spaced paths through the' block, a contact member adjustably threaded in each of the bores one of, said contacts being recessed within the bore to form a mercury retaining well therein, a globule of mercury received in the bores between each opposed pair of contact members, a means for locking said contact members in their adjusted positions, electrical leads secured to eachofsaidcontact members, a'switch actuating means secured to saidblock to induce ahigh speed reciprocal motion, ofthe block and contacts with reference to the globule of'mercury, to alternately make and break electrical contact between each pair of said contact members.

6..A high speed switchmechanism comprising, a dielectric block having a plurality of opposed longitudinal bores, said bores being in communication with each other to provide spaced paths through the block, a contact member adjustably receivable in each of the bores, a globule of .rnercury received in the bores between each opposed pair of contact members, one of each pair of contact members being provided at the inner end with a well, adapted to receive therein a portion of the globule of mercury, a means for locking said contact members in their adjusted positions, electrical leads secured to each ofsaid contact members, a switch actuating means secured to said block to induce a high speed reciprocal motion of the block and contacts with reference to the globule of mercury, to alternately make and break electrical contact between each pair of said contact members.

7. A high speed switch mechanism comprising, a dielectric block having a plurality of opposed longitudinal bores, said bores being in communication with each other to provide spaced paths through the block, one of each pair of bores being substantially larger than the other a contact member adjustably received in each of the bores, a globule of mercury received in the bores between each opposed pair of contact members, each large contact member having a well vdisposed in the end thereof adapted to receive therein a portion of the globule of mercury, a means for locking said contact members in their adjusted positions, electrical leads secured to each of said contact members, aswitch actuating means secured to said block to induce a high speed reciprocal motion of the block and contacts with reference to the globule of mercury, to alternately make and break electrical contact between each pair of said contact members.

8. Ahigh speed switch mechanism comprising, a dielectric block having a plurality of opposed longitudinal tapped bores, said bores being in communication with each other to provide spaced paths through the block, one of each pair of bores being substantially larger than the other, a contact member adjustably threaded in each of the bores, a globule of mercury receievd in the bores between each opposed pair of contact members, each large contact member having a well disposed in the end thereof adapted to receive therein a portion of the globule of mercury, means for locking said contact members in their adjusted positions, electrical leads secured to each of said contact members, a switch actuating means secured to said block to induce a high speed reciprocal globule of mercury, to alternately make and break eIe'c trical contact betweeneachi pair of said contact members.

9.: A high speed. switch mechanism comprising, a dielectric block having a bore therein, a globule of mercury received in said bore, a plug adapted to seal the'open end of said bore to form a cavity in said block, opposed bores in said block communicating with the said cavity, a bottom bore opposite the plug in said block angularly disposed with'respect to the opposed bores and communicating with the cavity, a contact pin receivable within each of said opposed bores and bottom bore, said oppose-d pins having their inner ends spaced from the cavity end ofsaid bores, said bottom contact pin being movable axially within its bore and into the globule ofmercury to vary the volumetric displacement of the globule of mercury and adjust the switch, an electrical lead connected to each of the pins and a switch actuating means secured to said block and contact to induce a reciprocal motion thereto with reference to the globule of mercury, to alternately make and break electrical contact between certain of the said contact members.

10. A high speed switch mechanism comprising, a dielectric block having a bore therein, a globule of mercury received in said bore, a plug adapted to seal the open end of said bore to form a cavity in said block, opposed bores in longitudinal alignment in said block communicating with the said cavity, a bottom bore oppositethe plug insaid block normally disposed with respect to the opposed bores and communicating with the cavity, a contactpin receivable within each of said opposed bores and bottom bore, said opposed pins having their inner ends spaced from the cavity end of said bores, said bottom contact pin being movable axially within its bore and into the globule of mercury to vary the volumetric displacement of the globule of mercury and adjust the switch, an electrical lead connected to each of the pins and a switch actuating means secured to said block and contact to induce a reciprocal motion thereto with reference to the globule of mercury, to alternately make and break electrical contact between certain of said contact members.

11. A high speed switch mechanism comprising, a dielectric block, first and second spaced electrical contact members molded within said block and extending exteriorly of the block, said second contact being provided with a cavity in the innermost end thereof, a globule of mercury within the block adjacent the inner ends of the spaced contact members and switch actuating means for reciprocating the block to make and break the said electrical contact.

12. A high speed switch mechanism comprising, a dielectric block, first and second spaced contact members molded within said block and extending exteriorly of the block, said second contact being provided with a cavity in the innermost end thereof consisting of a cup-shaped bore in said contact, a globuleof mercury within the block in electrical contact with thetinner ends of the spaced contact members and switch actuating means for reciprocating the block to make and break the said electrical contact.

References Cited in the file of this patent UNITED STATES PATENTS Geneslay Sept. 28, 1954

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