US2555139A

US2555139A - Sealing device

Info

Publication number: US2555139A
Application number: US61319A
Authority: US
Inventors: George F Knowles
Original assignee: SPECTRUM Manufacturing Co
Current assignee: SPECTRUM Manufacturing Co
Priority date: 1948-11-22
Filing date: 1948-11-22
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

May 29, 1951 G. F. KNowLEs 2,555,139

- sEALING DEVICE Filed Nov. 22. 194e 2 sheets-sheet 1 F/cii lll 6 49 Z756 42,58 40 48 gg/ 65 G. F. KNOWLES SEALING DEVICE May 29, 1951 2 Sheets-Sheet 2 Filed Nov. 22. 1948 mi? 57 Z0 Patented May 29, 1951 TED `'STA'l"iili`..S PAT ENT k(iF-.FSI CE -SEALING DEVICE .George ISinewl-es,'Hzwertewlrtv` Pa., .assigner .te

Spectrum Manufacturing Company, vPhiladellphia, Ba.,-a,corporation of Pennsylvania ApplicationNovem'ber 22, 1948, Serial-No.61,'319

5 Claims. .1 :This invention relates to machines` or devices for .sealing the Jedges .of .envelopes formed of thermoplastic..materialwhich is capable. of fusion orweldingby theapplication of heat. Moreparticularly, the invention relatesgto devicesforsealing the f edges. of such :envelopes bythe .application .of heat through two .jaw-like. electrodesbe tween which .the envelopes .are placed, This method ofsealingfsuch envelopes is Particularly applicable where .the lthermoplastic material lendsitselfto dielectricheating through .the application ofoa` highfrequencyvoltageto the two jaw-like electrodes.

`Transparent .thermoplastic sheets, such as sheets formed of eelluloseacetatahave come into use in the ;formati.on.of...sealed protective envelopes for such. objects. as social security cards and photographs which .the owner desires` .to` preserve, particularly .when it..is desired .to carry suchobjectsabout.andthey are subject to Wear.

Transparent yenvelopes thus .formed are durable and;attractve,..and they .will preserve the enclosedobject indefinitely.

The principalobject. of .the present invention is` to y provide a simple...device:f.or sealing.such envelopes with,afminimum-ofeeffortfon the partpf theoperator. "The device provided by the. inventioniis-.g especially adapted. for the; sealing. of e11- velQpes `about .smallcards or the like, such. as social security cards.

vThe invention-may `be fullyunderstood from thev followingdetailed description of a; preferred embodimentasrshown :in the accompanying .drawings., #wherein Fig. y1 is `a .side elevational @view .of a device constructed according to the present invention;

Fig. v2 is a plan view of i the same;

Fig. 3 is an elevational end view of the device taken from the right hand side of Fig. 1;

Fig. 4 is an enlarged sectional view taken .along line 4 4 of Fig. 1;

Fig. 5 is an enlarged sectionalview taken along line 5-5 of Fig. `v2, withy the jaws of the device Open;

Fig.y 6 is asimilar sectional view with the jaws closed;

Fig. '7 is an enlarged fragmentary sectional View showing the edge sealing of the envelope; and

Fig. 8is a perspective view of an envelope- Aenclosed social security card.

Referring more vparticularly `to lthe drawings, .there is provided -a stationarygsupporting frame designated generally by reference .character II). Mounted on an upright member I l `of said frame `:ifsjastationary .metalziawvlike electrode l2 which may be secured vvto said member by means of screws I3. This electrode is generally ofrectangular shape, and it has a forwardly VIVJrOJecting ange 4I4 (which` extends along `the v bottom and the twoverticall side edges A,of the electrode, said flange constituting the sealing portion of the electrode, as-hereinafter described. 4Secured to the face of the electrodelZ, Withintheabovementioned `flange, is .a resilient cushion member I5 (Fig. 5) .which preferablyforrned of Spenge rubber- An Outerfaeins 1.6.1..prefereb1y formed of .a .plasticniateriahis providedonthe cushion member .125. rlfhe cushion member I5 may be secured toelectrode I2 bymeans of suitable adhesive material, kand Athe facing I6 kmay be .similarlysecured tov thek cushionmember.

Amovable metallic jaw-lilgerelectrode l1, similar 4to .the electrode |52 .and in opposed relation thereto, .is arranged for cooperation with the electrode` I 24 toperforrn `the sealingunction The electrode Il alsohasa projecting ange I8extending along-arbe; bottom .endsde edges :thereof .and adaptedto cooperate with `theilange il 4 to eifeet the..see;1.ns .action- A .resilient cushion member |.9..an.d y.anassociated'.facing membeliz vare..IIL011I111-6C1 v0.11 thefaceof electrode I'I, these elementsbeingsimilar to elements I5 and I6 respectively. The lectrode Il issecured to an insulating plate-2l .by meensef screws 22 (Fig-.5), and plate 2I is in turn secured` toria metalplate .23,by means of bolts 24 (Fig. 2). It will be seen that theelectrode I lis insulated` fromthe supporting plate 23. The platev 23 is secured to a s lidable carriage 25 by means of `screws 26.

The carriage 25 is slidablyesnpported by the frame. I 0, and its outerend is pivotally connected et. 21 to e; lnkfnffwhieh v11n turn. isrivetelly connectedat 2-9;to a lever,30. The-upper portion ,of lever ..30 isbifurcated (Fig. 3) andthe extending .arms 3| thereof ...are vpivotally yconnected ;to a bracket r32.1 by means of a pivot .pin .3,31 The bracket 32 is -v mounted on :the frame I0, above .the sliding carriage 2,5, by means of yscrews v34.

The lower portion ofl lever 3D is formed so .as .to provide a pair of spaced bosses 35 and v:356 (Fig. .3) and a third boss 31. Thebosvses 35.and 36 .accommodate rods 38 and39 (Fig. 2) respectively,

' .whichy areprovided with shoulders against which rest -washersf38a and 39a. .'Ihebosses 35- andA 36 .are held .agaiilstsed Washers by-.helieel-.Springs 42 andf43 Whichsurro-iind thefouterreduced-portions.off.rods .38.-a1id 3S- .The @merende eisaid rods credere. .edite accommodate thumb nuts .40 and 4l.. .against .whehithev'springs :42 and A4.3 act. SpringsAL-.andff.are arranged :onathe two 3 rods between the washers 38a, 39a and the stationary frame I0. The springs normally maintain the operating parts in the positions shown.

The third boss 31 on lever 3|] is threaded to receive an adjustable thumb screw 46 which serves as a stop, as hereinafter described. The boss 31 is split and carries an associated bolt 41, by means of which the screw 46 may be held securely in an adjusted position.

The

rods

38 and 39 are slidably supported by the stationary frame, and the rods carry

collars

48, 49 and 59, 5I (Figs. 1 and 2) which are secured to the rods and move therewith. A shaft 52 extends transversely below the

rods

38 and 39 and is rotatably supported by the frame I0. This shaft has keyed thereto a pair of

sleeves

53 and 54 which carry extending arms 55 and 56. The ends of said arms extend between the collars 48 and 49 and between the collars 56 and 5l respectively, so that rotary movement of said arms effects sliding movement of the

rods

38 and 39. A sleeve or collar 51 is keyed to one end of shaft 52, .and carries a crank arm 58, to the outer end of which an actuating rod 59 is pivotally connected at 6I). The rod 59 extends downward to a treadle 6I and is pivotally secured thereto at 62. The treadle 6I is pivotally mounted at 63 on a stationary support 64.

The device is adapted to seal three edges of a small envelope, such as shown at 65 in Fig. 8, for enclosing a small flat object such as the social security card 66 shown in the illustration. The envelope is formed of a single sheet which is folded at the top edge 61, the other three edges being sealed by the sealing device. The sealing operation is effected by dielectric heating, and to this end a high frequency voltage is applied between the metal electrodes I2 and I1. The stationary electrode I2 is electrically connected to the metal frame I by virtue of its attachment thereto, and an insulated conductor 68 (see Fig. 1) is connected to the frame and extends to one terminal of a suitable voltage supply source (not shown). The latter may be a conventional high frequency voltage generator and requires no illustration. A coaxial tuner 69 may be connected to the other terminal of said source. The coaxial tuner is stationary and is provided with a contact nger 10 which is in wiping engagement with the movable electrode I1.

The high frequency voltage generator is normally maintained in inoperative condition by a micro-switch 1I biased to open position. The micro-switch is supported by `a bracket 12 mounted on an upright member 13 of the frame I0. A collar 14 on rod 38 engages the micro-switch arm 15 to close the switch at a certain point in the operating cycle, as hereinafter described.

Normally the two electrodes are open as shown in Fig. 5, forming a slot-like space in which the folded envelope member and the associated card may be placed. An important feature of the invention is the arrangement for supporting the envelope member and the associated card, as now to be described. A pair of rotatable Iarms 16 and 11 (Fig. 4) are rotatably supported on rod 38 and are urged into engagement with the electrodes by a spring 18. These arms have

fiat nger portions

19 and 80 which normally span the open electrodes. The arms are prevented from moving longitudinally on rod 38 by Ia pair of collars 8| and 82 (Fig. 1). Similarly, a pair of arms 83 and 84 (Fig. 4), having linger

portions

85 and 86, are rotatably supported on rod 38 and are urged into engagement with the electrodes by a spring 81. Collars 88 and 89 (Fig. 5) serve to prevent the latter arms from moving longitudinally on rod 39. By virtue of this supporting arrangement, it is necessary merely to drop the folded envelope member and the associated card into the space between the electrodes as shown in Fig, 5. When the electrodes are open as shown in Fig. 5, the envelope-supporting elements span the electrodes but at that time the switch 1I is open so that there is no voltage applied across the electrodes and no short circuiting action through the envelope-supporting elements.

When the device is actuated by depressing the treadle 6I, the movable electrode I1 is moved to closed position, as shown in Fig. 6, and the resilient elements carried by the electrodes grip the envelope member firmly while leaving free the three edges to be sealed. At the same time, the above-described supporting elements are moved out of engagement with the electrode Il, as may be seen in Fig. 6. However, the envelope member is gripped by the resilient elements on the electrodes before the supporting elements are moved to non-supporting position. The switch 1| is closed after the supporting

fingers

19, 86, 85, 86 have been moved out of engagement with the electrode I1. This operating sequence is necessary in order that the said fingers will not form a short circuit between'the electrodes.

When the treadle 6I is released, the reverse sequence takes place. First the switch 1I opens, then the supporting fingers i 9, 8D, 85, 86 move to supporting position, and finally the j aw-like electrodes release the envelope.

The detailed operation of the device to give the desired operating sequence may be understood by considering Figs. 1 and 2. As the treadle 6I is depressed, the springs 42, 43 cause lever 30 to move as though the latter were rigidly connected to

rods

38, 39. As the

rods

38, 39 and the lever 30 move toward the left the

springs

44, 45 are compressed. When electrode I1 reaches the closed position, lever 3IJ is stopped but the

rods

38, 39 are able to continue their movement against the resilience of springs 42, 43. During the continued movement of

rods

38, 39, the envelope-supporting fingers move out of engagement with electrode I1 and then the switch 1I is closed.

When the treadle is released, the springs 42, 43 move the

rods

38, 39 toward the right, causing the switch 1I to open and moving the envelope-supporting fingers to supporting position. Meanwhile the

springs

44, 45 urge lever 30 toward the right and nally cause the electrode I1 to release the envelope.

It will be apparent that the device is designed to give the above-described operating sequence. To this end springs 42, 43 are somewhat heavier or stiffer than

springs

44, 45.

When the movable electrode I 1 moves to closed position as above described, the flanges I4 and I8 of the two electrodes exert pressure on the edges of the envelope member to be sealed. When the high frequency voltage is applied, the said edges are subjected to simultaneous pressure and heat, the heating of the thermoplastic material being effected dielectrically as will be well understood.- As a result of the heat and pressure, the edges are fused or sealed as shown at 90 in Fig. 7. This requires only a few seconds during which the Ioperator holds the treadle 6I in depressed position. During the sealing operation, there is a tendency toward slight enlargement of the envelope as the softened thermoplastic material flows slightly outward under the exerted pressure. However, the construction of the envelope-supporting elements, as shown in Fig. 4, permit the

ngers

19, 80, 85, 86 to return even though the edges oi the envelope may be extended by the sealing operation.

Mention was made previously -oi the adjustable stop screw 46. This stop element does not normally become effective, but in the event that the device is actuated without placing an envelope member and associated card between the electrodes, the end of screw 16 engages the adjacent portion of the frame l0 and prevents sufficient movement of electrode l1 to cause engagement of the electrode flanges I 4 and I8. This prevents short circuiting of the high frequency source which would otherwise be caused by direct engagement of the electrodes.

Normally, the operating mechanism will be housed within a casing, a portion of which is shown at 9|. Such casing may be provided with a slot opening 92 into which a folded envelope member and an associated card may be dropped.

It will be apparent from the foregoing description that the device provided by the invention is simple in construction and operation and is easy to operate. The operator simply drops a folded envel-ope member and associated card into the slot opening, depresses the treadle 6l for a few seconds, and then removes the sealed envelope. Thus it is possible for a single operator to seal envelopes at a rapid rate.

While a preferred embodiment of the device has been illustrated and described, it will be apparent that the invention is not limited to the structural details thereof since it is obvious that the various modications could be made with-out departing from the essential structure and mode of operation.

I claim:

1. In a device for sealing the edges of envelopes formed of thermoplastic material, a stationary vertical electrode, a movable vertical electrode arranged in cooperative relation with said stationary electrode, metallic means normally engaging said electrodes for supporting an envelope between said electrodes when the latter are open, a normally-open switch adapted to control application of a voltage to said electrodes, a manually-operable member, and means operable by said member to actuate said movable electrode to closed position, to move said envelope supporting means out of engagement with said movable electrode, and to close said switch, in the recited sequence.

2. In a device for sealing the edges of envelopes formed of thermoplastic material, a, stationary vertical electrode, a movable vertical electrode arranged in cooperative relation with said stationary electrode, metallic means comprising spring-biased lingers normally engaging said electrodes for supporting an envelope between said electrodes when the latter are open, a normally-open switch adapted to control application of a voltage to said electrodes, a manually-operable member, and means operable by said member to actuate said movable electrode to closed position, to move said envelope supporting means out of engagement with said movable electrode, and to close said switch, in the recited sequence.

3. In a device for sealing the edges of envelopes formed of thermoplastic material, a supporting frame, a stationary jaw-like electrode mounted on said frame, a movable jaw-like electrode arranged in cooperative association with said stationary electrode, movable carriage means for said movable electrode supported by said frame, metallic means normally engaging said electrodes for supporting an envelope between said elec trodes when the latter are open, and means for moving said carriage means to effect closure of said electrodes, and for moving said envelopesupporting means out of engagement with one electrode.

4. In a device for sealing the edges of envelopes formed of thermoplastic material, a supporting frame, a stationary jaw-like electrode mounted on said frame, a movable jaw-like electrode arranged in cooperative association with said stationary electrode, movable carriage means for said movable electrode supported by said frame, metallic means normally engaging said electrodes for supporting an envelope between said electrodes when the latter are open, a norw mally-open switch carried by said frame and adapted to control application of a voltage to said electrodes, a manually-operable member, means operable by said member to move said carriage means to effect closure of said electrodes, other means operable by said member to move said envelope-supporting means out of engagement with one electrode, and still other means operable by said member to effect closure of said switch.

5. In a device of the character described, a pair of relatively movable electrodes arranged to receive therebetween an object for treatment by said electrodes. metallic means normally engaging said electrodes for supporting said object between said electrodes when the latter are open, a normally-open switch adapted to control application of a voltage to said electrodes, a manually-operable member, and means operable by said member to elect closure of said electrodes, to move said supporting means out of engagement with one of said electrodes, and to close said switch, in the recited sequence.

GEORGE F. KNOWLES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,079,708 Hart May 11, 1937 2,376,360 Irmscher May 22, 1945 2,401,991 Walton et al June 11, 1946 2,402,298 Salfisberg June 18, 1946 2,434,325 Vesconte Jan. 13, 1948 2,477,214 Story July 26, 1949 2,512,751 Proctor et al June 27, 1950