US3392070A

US3392070A - Method and apparatus for sheathing terminals

Info

Publication number: US3392070A
Application number: US349672A
Authority: US
Inventors: Walter E Gropp
Original assignee: Berg Electronics Inc
Current assignee: Berg Electronics Inc
Priority date: 1964-03-05
Filing date: 1964-03-05
Publication date: 1968-07-09
Anticipated expiration: 1985-07-09

Description

July 9, 1968 w. E. GROPP 3,392,070

METHOD AND APPARATUS FOR SHEATHING TERMINALS Filed March 5, 1964 7 Sheets-Sheet 1 w. E. GROPP 3,392,070

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METHOD AND APPARATUS FOR SHEATHING TERMINALS Filed March 5, 1964 '7 Sheets-Sheet 5 INVENTOR. M77 67 1:. 670

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July 9, 1968 w. E. GROPP 3,392,070

METHOD AND APPARATUS FOR SHEATHING TERMINALS Filed March 5, 1964 7 Sheets-Sheet '7 FETE NL I- 6 m 4 Tra /V5945" United States PatentO 3,392,070 METHOD AND APPARATUS FOR SI-IEATHING TERMINALS Walter E. Gropp, New Cumberland, Pa., assignor to Berg Electronics, Inc., New Cumberland, Pa., a corporation of Pennsylvania Filed Mar. 5, 1964, Ser. No. 349,672 9 Claims. (Cl. 156-55) ABSTRACT OF THE DISCLOSURE An apparatus and method for sheathing electric terminals wherein a loop formed of two insulating strips is fed between sealing dies, terminals are inserted between the strips, the dies are closed and the overlapping portions of the strips between the terminals are bonded together.

This invention relates to sheathed electrical terminals and has particular reference to a new and improved technique for efliciently and accurately enclosing a terminal secured on a conductor in a sheath of resilient, flexible electrical insulating material so as to protect the terminal against undesired electrical contact with other current conductors. The invention provides a simple, economical method in which one or more terminals are sandwiched between heat sealable electrical insulating material, heat sealing dies mounted in a reciprocating press clamp and seal the insulating material around each of such terminals, and the insulated terminals are then severed from the strip. The method and apparatus for carrying out the method may be readily adapted to sheathe various types of terminals and to sheathe terminals so as to meet a wide variety of requirements or specifications.

A principal object of the invention is to provide a new and improved method of electrically insulating terminals secured to a conductor.

Another object of the invention is to provide a new and improved apparatus mounted in a reciprocating press for enclosing terminals in a sheath of resilient flexible electrical insulating material. 7

Other and further objects of the invention will be apparent from the following description and claims and may be understood by reference to the accompanying drawings, of which there are seven sheets, which by way of illustration show preferred embodiments of the invention and what I now consider to be the best mode of applying the principles thereof. Other embodiments of the invention may be used without departing from the scope of the present invention as set forth in the appended claims.

In the drawings:

FIG. 1 is a perspective view of part of the apparatus in its open position, with the upper die displaced ninety degrees from its true open position and with the tape feeding mechanism in its retracted position;

FIG. 2 is a plan view of the fixed die of FIG. 1 with the feed mechanism in its advanced position;

FIG. 3 is an exploded view of the feed mechanism;

FIG. 4 is a plan view of the strips of heat sealable insulating material with a series of terminals enclosed between said strips prior to the cutting operation;

FIG. 5 is an enlarged longitudinal sectional view through the upper and lower dies in their open position, with the strips of insulating material in their advanced position ready for the insertion of the electrical terminals between such strips; I

FIG. 6 is a view similar to FIG. 5 but showing the dies in their closed position; 4

FIG. 7 is a fragmentary sectional view taken along the line 77 of FIG. 5;

ice

FIG. 8 is a fragmentary view similar to FIG. 6 and illustrating the severing operation;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 6;

FIG. 10 is a sectional view of a sheathed terminal taken along the line 10-10 of FIG. 4;

FIG. 11 is a section through a series of sheathed terminals taken on the line 11-11 of FIG. 10;

FIG. 12 is a perspective view of a modification with the feed mechanism in its retracted position;

FIG. 13 is a view similar to FIG. 12 but with the feed mechanism in an advanced position;

FIG. 14 is a fragmentary view similar to FIG. 12 of the feed mechanism in its advanced position;

FIG. 15 is a plan view, partly in section, of two sheathed terminals;

FIG. 16 is a sectional view of a flag type sheathed terminal; and

FIG. 17 is a fragmentary view of a strip of flag type terminals prior to severing of the terminals from the strip.

As illustrated in FIG. 1, the apparatus comprises a reciprocable sealing punch and cutter assembly 20 and a fixed die block assembly 22 upon which a strip feed mechanism 24 is mounted. The sealing punch and cutter assembly 20 is fixed to a press ram so as to move therewith, the press being a three-position reciprocating type press having an open position at the top of the stroke, a closed position at the bottom of the stroke, and an intermediate position wherein the sealing punch and cutter assembly 20 is positioned as illustrated in FIG. 6 relative to the die block assembly 22 while heat is generated in the sheathing material so as to bond the clamped portions together. Conventional means are provided for mounting spools or

coils

26 and 28 of heat sealable electrical insulating material so that the

strips

30 and 32 thereof may be fed by the feed mechanism into position between the punch and cutter assembly 20 and the die block assembly 22 when open.

The sealing punch and cutter assembly 20 is mounted on the press ram so as to reciprocate therewith and includes a mounting plate 40 adapted to be fixed to the ram of the press, a series of sealing punches or dies 42, and a series of cutters or blades 44. The apparatus is set up to produce a unit of two sheathed terminals as illustrated in FIG. 15, so the sealing punches or dies are made in units of two with three spaced sealing faces 46, 48 and 50 separated by cavities 52 and 54. Each of the cavities is adapted to freely accommodate the upper part of a terminal and the insulating material during the sealing operation as illustrated in FIG. 6. The sealing faces 46 and 48 are adapted to straddle a terminal and the overlying insulating material. Each of the sealing dies 42 is carried by a series of pins 56 which are reciprocably mounted in suitable bores or guides in the plate 40, the pins 56 being provided with heads 58 which are accommodated in recesses in the upper face of the plate 40. A coil spring 60 is disposed about each of the pins 56 and is confined between the plate 40 and the die 42 whereby the die 42 is biased to its extended position as illustrated in FIG. 5. The cutters or blades 44 are suitably secured against the plate 40 so that the cutting edges of the blades 44 are normally recessed with respect to the faces 46, 48 and 50 of the sealing dies when the latter are in their extended position as shown in FIG. 5. The cutters 44 are positioned so that the sealing dies 42 will clamp the strips of insulating

material

30 and 32 together as illustrated in FIG. 6, with the cutter blades recessed or inoperative.

The die block assembly 22 includes a base or plate 70 adapted to be fixed to the bed of the press below the sealing punch and cutter assembly. A fixed sealing die 72 is secured to the plate 70 and the upper face of the die 72 is provided with a series of

cavities

74 and 76 similar 3 to the cavities 52 and 54, the

cavities

74 and 76 being separated by flat sealing faces 78, 80 and 82 which are cooperable with the flat sealing faces 46, 48 and 50 when the dies are in their closed position for clamping the heat sealable strips of insulating material therebetween during the heating cycle so as to bond such material together .to form a sheath around the terminals.

The assembly 22 further includes a nylon guide 84 provided with a series of slots 86 for accommodating and frictionally holding the insulation-covered conductors to which the terminals are secured, the guide 84 being fixedly secured to the front of the die 72. The guide 84 further includes a series of slots 88 for accommodating the front edges of the cutters 44 as shown in FIG. 9. The cavities 52 and 54 in the movable die 42 and the

cavities

74 and 76 in the fixed die 72 include channels 90 of reduced cross section for accommodating the insulation around the conductor.

As shown in FIG. 10, the electrical terminal 92 includes a socket or receptacle and is crimped at 94 to the hated end of the conductor 96, the conductor insulation 98 having been removed.

The feed mechanism 24 for the tape comprises, as illustrated in FIG. 3, a reciprocating feed bar 100 which is reciprocably mounted in guides 102 and 104 formed in guide blocks 106 and 108 mounted upon the plate 70. A double acting air cylinder 110 is connected at one end to the block 108 and a piston rod 112 which projects from the other end of the cylinder is connected by cross bar 114 to one end of the feed bar 100 for reciprocating the latter. The piston rod 112 is connected on the end thereof inside the cylinder 110 to a double acting piston which is adapted to move in one direction or the other by air under pressure supplied to the cylinder through air pressure lines 116 and 118 under the control of a valve 120, the valve 120 serving to connect one side of the cylinder to the source of air pressure while the other side is vented to atmosphere. The valve 120 is suitably actuated when the press ram is open to energize the air cylinder 110 so as to effect the advance and retraction strokes of the feed mechanism so as to feed insulating tape between the sealing dies for sheathing the terminals.

The feed bar 100 carries a pair of posts 122 which provide bearings for a shaft 124 which carries feed finger 126, and a collar 128 is fixed to one end of the shaft 124. A coil spring 130 disposed about the shaft has one end secured to a pin 132 on the shaft 124 and the other end of the spring reacts on one of the posts 122 so as to bias the shaft 124 to position the feed finger 126 as illustrated in FIGS. 1 and 3. Pin 133 carried by one of the posts 122 serves as a stop -for limiting counterclockwise rotation of the shaft 124. The posts 122 are secured in the slots 135 in the bar 100 by a pin 134 which extends through aligned holes in the posts 122 and in the bar 100'.

As the tape is stripped from the

reels

26 and 28 it is fed through guide slots provided between the block 136, the block 106, and the plate 138, the upper face of the block 136 being relieved as shown in FIG. 3 and the lower face being relieved in the same manner so as to provide a slot between 136 and the cover plate 138 and a corresponding slot between the block 136 and the block 106. The upper face of the block 136 is provided with a cross slot 140 in which drag bar 142 is disposed, while a drag bar 144 is disposed in the corresponding slot in the under side of the block 136. The slots through which the

strips

30 and 32 of tape pass are above the bar 142 and below the bar 144. A coil spring 146 biases the bars 142 and 144 apart so that the bar 142 and the under side of the plate 138 provide a frictional drag for the tape 30, while the bar 144 and the upper surface of the block 106 provide a frictional drag for the strip 32. The upper surface of the block is also provided with a slot 148 which receives one leg of a clip 150, the other leg of which is received in a corresponding slot in the under side of the block 136. The clip 150 abuts the thickest part of the block 136 and forms one side of the slots for the tape. By substituting clips 150 of narrower width, the slots provided by the

blocks

106, 136 and 138 may be widened to accommodate a wider strip of tape.

As illustrated in FIG. 1, the lead ends of the

tapes

30 and 32 are joined together to form a loop 152 into which the feed finger 126 projects. Thus as the feed finger 126 is advanced by the air cylinder 110, two flexible strips of heat scalable insulating material will be fed between the upper and lower sealing dies 42 and 72. As illustrated in FIG. 2, the tape is fed above the

cavities

74, 76 in the lower sealing die 72 upon the advancing of the feed bar 100, and engagement of the pin 154 on the shaft 124 with the abutment 156 causes the shaft 124 to rotate so as to turn the feed finger 126 to a vertical position as illustrated in FIG. 5, thereby separating the upper and lower strips of tape 30 and 32'and providing space therebetween whereby the terminals may be inserted between the

strips

30 and 32 as illustrated in FIG. 7. When the air cylinder retracts the feed bar 100, the spring will return the feed finger 126 to its horizontal position.

A series of locating pins 158 are carried by bars 160, which in turn are carried by a plate 162 which is slidably mounted for movement toward and away from die 72 on a series of pins 164 carried by the die 72, and as illustrated in FIG. 7, a series of springs 166 react on the plate 162 and on the lower die 72 for biasing the plate 162 away from the die 72. The latch 168 is released by the pins 170 carried by the upper die assembly 20. The spaces between bars are in line with slots 88 and accommodate the rear edges of cutters 44. A bar 172 is pivoted by links 176 and pins 178 to the guide bar 100 and is movable therewith as the guide bar advances and retracts. The links 176 are accommodated in recesses in the upper face of feed bar 100. A keeper 180 cooperates with the upper face of the guide bar 100 to provide a slot for the bar 172. As the bar 172 advances with the feed bar, a cam surface182 on the lead end of bar 172 engages a fixed cam surface 184 on the plate 70, and the resulting action shifts the bar 172 against the plate 162 as illustrated in FIG. 7 so as to move the plate 162 and the locating pins 158 carried thereby into position to provide fixed stops for the terminals 92. This serves to accurately lo cate the ends of the sockets or receptacles of the terminals 92 with respect to the edges 186 of the

strips

30 and 32 prior to the sealing operation. A spring loaded pin 173 functions to retract bar 172.

As the plate 162 is moved toward the die 72, the latches 168 engage the plate 162 and serve to lock it in the position as illustrated in FIG. 7. After retraction of the feed bar 100 and the feed finger 126, the press ram closes the sealing dies to the position as illustrated in FIG. 6 so as to cause the sealing faces of the dies to clamp spaced areas of the

strips

30 and 32 together around the terminal and in areas corresponding with the areas provided by the sealing faces 46, 48 and 50 and the corresponding opposed faces 78, 80 and 82 of the lower sealing die 72. However, prior to the closing of the sealing dies the pins release latches 168 as the press ram descends to permit return of plate 162 and locating pins 158 to the position as shown in FIG. 9. The cavities 52 and 54 in the upper sealing die and the corresponding cavities in the lower sealing die are aligned to freely accommodate the erminals and the insulating material when the dies are closed as shown in FIG. 6 during the heating cycle. While the areas of the sealing material are clamped together, the dies function as electrodes to pass a timed radio frequency current through such areas to heat the material at the interface suflicient to bond the material together at such areas without significant heating of other portions of the tape-particularly the portions of the tape in contact with the terminals. Such current may be generated in accordance with conventional techniques. After such current is cut off, the material is allowed to cool and set for a short time (a second or more, depending on the mass of the heated material) before the severing operation is carried out.

After the heating cycle, the press is actuated to move the ram to its closed position so as to cause the cutters 44 to sever the sheathed terminals from the strips as shown in FIG. 8. The cutting operation also severs the sheathed terminals into units, in this case units of two, as shown in FIG. 15. It will be evident that by using various arrangements of cutters and sealing dies, the sheathed terminals may be made in units of one or of any desired number within the capacity of the apparatus. For example, FIG. 16 shows a single sheathed flag type terminal which is individually cut from a strip, as shown in FIG. 17.

During the sealing operation the heat sealable insulating material may be bonded to the insulation of the conductor 24 if desired. As appears from FIG. 8, the sealing operation will bond portions of the

strips

30 and 32 upstream relative to the cutters 44 so that after the cutting operation the lead ends of the strips 30 and 32 -will be joined'together to form a loop for engagement by the feed finger 126 as it moves through its feed stroke for feeding another length of heat sealable material between the sealing dies after the previously sheathed terminals have been removed from the dies following the opening thereof. Thus, after the press opens the dies 42 and 72, the sheathed terminals are removed and the valve 120 is actuated to effect the feed stroke of the feed finger 126. At the end of the feed stroke the feed finger 126 turns so as to spread the

strips

30 and 32 as illustrated in FIG. 5, and then the terminals to be sheathed are located on the pins 158. The valve 120 is then actuated to energize the air cylinder 110 so as to retract the feed finger 126. The initial retractile movement of the feed finger 126 permits it to return to its horizontal position, permitting it to pass between the upper strip 30 and the row of terminals located on the pins 158. Upon the return of the feed finger 126 to its retracted position as shown in FIG. 6, the press is actuated to close the dies 42, 72 to the position as shown in FIG. 6 for the heating cycle, and at the end of the heating cycle the press is actuated to move the ram to its closed position, thereby causing the cutters 44 to sever the sheathed terminals from each other and from the strip.

In sheathing terminals in units of two as illustrated in FIG. 15, the cutters cut entirely across the bonded strips and there is no scrap. However, in sheathing some terminals, such for example as the flags illustrated in FIGS. 1-6 and 17, there will necessarily be some scrap, and it may be desirable in such case not to sever the bonded strips but merely to cut the sheathed terminals from the bonded strips along the lines indicated in FIG. 17, leaving a continuous part of the strip along the edge 200 with the scrap portions 202 on the other edge of the strip connected thereto. This leaves the scrap in continuous strip form which may be removed with the apparatus illustrated in FIGS. 12, 13 and 14. Such apparatus comprises scrap feeding or removal mechanism and is in addition to the apparatus'illustrated in FIGS. 1 to 9.

As illustrated in FIG. 12, the base 70 is provided with a laterally extending arm 204 provided with a cam 206 at its end. A clamp indicated generally at 208 is mounted on the end of the feed bar 100. The clamp comprises a fixed clamping member 210 and a pivoted clamping member 212 pivoted upon a pin 214 carried by the guide bar 100. A coil spring 216 disposed about the pin 214 reacts on the pivoted clamping member 212 so as to bias the same to its closed position as illustrated in FIG. 12. The base 70 is provided with a ledge 218 and a V-guide 220 over which the scrap strip 200 is fed.

In the retracted position of the

clamp

210, 212 as shown in FIG. 12, the scrap strip is clamped between the jaws of the clamping members so that as the feed bar 100 moves on its feed stroke as illustrated in FIG. 13, the

scrap strip 200 is pulled out from between the dies 42 and 72. As the feed bar 100 approaches the end of its feed stroke the end 222 of the clamping member 212 engages the cam 206 which shifts the clamping member 212 to the position illustrated in FIG. 14 where it is maintained by a latch 224 carried by the fixed plate 226 which is 'also mounted on the end of the feed bar-.100. The spring 216 permits the clamping member 212 to move axially of the pin 214 and away from'the feed bar 100 so as to ride over the latch 224 as it pivots counterclockwise in response to the engagement of the cam 206 by the portion 222. This serves to lock the

clamp

210, 212 in its open position and to release the scrap strip 200. The

clamp

210, 212 will remain open during the retraction of the feed bar 100 until the member 212 engages the abutment 230 on the platewhich displaces the clamp member 212 against the spring 216 sufficiently to release it from the latch 224 and permit it to return to its closed position as shown in FIG. 12. As the clamping member 212 moves to close, it will catch'the scrap strip 200 held by the V-guide 220' and clamp such scrap strip against the fixed clamping member 210 so that upon the next feed stroke of the feed bar 100 another length of scrap strip will be removed from between the dies 42 and 72. Since the bonded strips are not severed during the cutting operation, this will serve to feed the

strips

30 and 32 between the dies 42 and 72, although this will be done in any event by the reciprocation of the feed finger 126.

The insulating plastic strips 30 and 32 are sealed together around terminals 92 by localized radio frequency heating. When the upper and lower dies 42 and 72 are closed, the

strips

30 and 32 are tightly sandwiched between sealing surfaces 46, 48 and 50 of the upper die 42, and 78, and 82 of the lower die 72. The output taps of a tank circuit radio frequency channel are attached to upper die 42 and lower die 72. The plastic strips secured between the sealing surfaces of the upper and lower dies are sealed together, when the radio frequency generator is in operation, by the di-electric heating induced by the high density radio frequency field generated in the plastic sandwiched between the sealing surfaces. The plastic tape immediately adjacent to the terminals 92 is not heated or melted during the sealing step because it is not subjected to a high density radio frequency field. Thus the contact surface of the terminals 92 does not become coated or insulated during the sealing step.

By attaching the center tap of the output coil of the radio frequency generator to plate 162, the radio frequency current may be kept out of terminals 92 and the wires 98 connected thereto. By grounding the terminals and wires, the operator of the sealing machine cannot he accidentally burned by touching a wire at radio frequency potential.

It has been observed that when the layers of heat sealable material, such as a commercially available vinyl resin tape, are electronically heat sealed, the resulting sealed seam is thinner than the original two layers due 'to the fact that melted material is displaced from the seal to the adjacent space. Preferably the sealing dies are shaped so that such displaced material is forced against the sheathed terminal so as to anchor the sheath in relation to the terminal and accurately locate the open side of the receptacle relative to the edge of the access opening in the sheath. Preferably the heating cycle is timed so as to closely control the heating of the heat scalable material so as to avoid overheating of the tape.

The upper die 42 is preferably made of brass and it and other parts of the radio frequency generating circuit are suitably shielded by grounded sheet metal shrouds to prevent the undesired distribution of radio frequency W aves open switch so that when the operator closes the foot switch the valve 120 will operate to admit air to the cylinder so as to effect the feed stroke of the tape feeding mechanism to position two strips of heat scalable tape between the sealing dies. The operator then loads the terminals 92 between the spaced strips 30 and 32, utilizing the locating pins 158 to accurately and properly position the terminals 92 for the sealing operation and so as to accurately locate the terminal receptacle relative to the edges of the strips which form the edges of the access opening in the sheath.

The control circuit for the apparatus further includes two normally open push button operated switches which when held down, i.e., closed, by the operator, actuate the value 120 to admit air to the cylinder to effect the retraction of the tape feeding mechanism. At the end of the retraction of the feed mechanism the press ram is automatically actuated to close the dies 42 and 72 (FIG. 6). The radio frequency generator is controlled so that when the operator releases the aforesaid push button operated switches the radio frequency generator is energized, this initiating the heating or sealing cycle. During the heating cycle (about 3-4 seconds) a high density radio frequency field is generated in the plastic material sandwiched between the sealing surfaces of the dies, heating such material to about 400 F. so as to unite the areas under the sealing pressure of the dies. After the radio frequency generator is deenergized, the sealing dies are held closed as in FIG. 6 for a short interval (about one second) so as to permit the heated portions of the tape to cool before the press ram continues its closing movement to effect the cutting operation wherein the strip is severed so as to separate the terminals (FIG. 8). The press does not stop in its closed position, however, but opens after the severing operation so as to position the apparatus for the next cycle and to permit the removal of the sheathed terminals.

Instead of utilizing a radio frequency generator to generate heat in the tape for sealing it to form the sheaths, any other conventional or suitable method of heating may be employed, such for example as heating the sealing dies. It is preferred, however, to use the radio frequency method of heating the plastic tape directly as this does not heat the dies, although they do warm up to some extent by conduction. Where the heating cycle is time controlled some adjustment may be desirable to compensate for the warm up of the dies. It will be understood also that some adjustment of the time of the heating cycle is desirable to take care of tapes of different thicknesses so as to heat the sealing areas of the tape adequately without overheating. The method and apparatus herein disclosed with appropriate modification of the dies may be employed to encapsulate other components, such as diodes, coils etc., and reference herein to terminals is intended to include other such components.

While I have illustrated and described preferred embodiments of my invention, it is understood that these are capable of modification, and I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. That method of insulating a series of electric terminals which comprises: feeding two overlapping flexible strips of heat sealable electrical insulating material with their lead ends joined in one direction between opposed cooperative reciprocable heat sealing dies while said dies are open, separating said strips so as to position them in spaced relation, laterally inserting a series of terminals between said separated strips, accurately locating said terminals Withrespect to an edge of one of said strips, closing said sealing dies so as to clamp spaced overlapping areas of said strips together between adjacent terminals and while said strips are so clamped bonding the clamped together portions of said strips together, and cutting through such bonded portions of said strips so as to leave an insulating sheath around each terminal and to sever such sheaths from said strips and to form a new loop.

2. That method of insulating a series of electric terminals which comprises: axially feeding two overlapping flexible strips of heat scalable electrical insulating material between opposed cooperative sealing dies when open, positioning terminal holders between said strips, laterally inserting a series of terminals between said strips and removably mounting the terminals on said holders so as to accurately locate said terminals with respect to an edge of one of said strips, closing said sealing dies so as to clamp spaced overlapping portions of said strips together between adjacent terminals, bonding such portions together to form an insulating sheath around each terminal, cutting through such bonded portions of said strips so as to sever such sheaths from said strips and removing said holders from between the sealing dies.

3. 'That method of insulating a series of electric terminals which comprises positioning longitudinally feeding two adjacent flexible strips of heat scalable insulating material from supply rolls in spaced overlapping relation between opposed cooperative sealing dies when open, laterally inserting and accurately locating a series of terminals in spaced relation between said strips along the length thereof, closing said sealing dies so as tovclamp spaced overlapping areas of said strips together between adjacent terminals and While said strips are so clamped together bonding such clamped portions together to form a sheath around each terminal, and severing the sheathed terminals from said strips and removing the sheathed terminals from between said sealing dies.

4. That method according to claim 3 wherein the severing of said sheathed terminals leaves a continuous strip of scrap material connected to the lead ends of unused strip material, and wherein said method includes the step of pulling the scrap material from between said sealing dies so as to thereby position unused strip material between said sealing dies for the next cycle of operation.

5. That method of insulating a series of electric terminals which comprises unwinding two coils of heat seal.- able strips of electrical insulating material, joining the lead ends of said strips to form a loop, tractively pulling said loop away from the coils so as to unwind the same and position the uncoiled portions of said strips in overlapping parallel relation between two open sealing dies, spreading said portions of said strips apart, laterally inserting and accurately locating a series of terminals in spaced relation between the spaced apart portions of said strips, simultaneously clamping spaced areas of said strips together between adjacent terminals by closing the sealing dies and while said strips are so clamped heating the clamped together areas of said strips so as to bond together the interengaging portions of said strips and thus form an insulating sheath about each terminal and a new loop simultaneously cutting the strips through the bonded portions thereof so as to sever the sheaths from each other and from the new loop, separating the sealing dies so as to free said strips and sheaths, and removing the insulated terminals from between said dies.

6. That method of insulating a series of electric terminals at the same time which comprises forming heat sealable material in strip form to provide a reverse bend loop at the lead end thereof, moving the loop portion of the material axially to extend the strip material and position two strips of said material in overlapping parallelrelation, inserting and accurately locating a series of terminals in spaced relation between the overlapping portions of said strips, clamping spaced areas of said strips together between adjacent terminals with sealing dies and while said strips are so clamped heating the clamped together areas of said strips so as to bond together the interengaging portions of said strips and thus form an insulating sheath about each terminal, and cut-ting the strips through the bonded portions between adjacent sheaths so as to sever the sheaths from said strips.

7. Apparatus for insulating electric terminals with material from insulating heat sealable strips joined together at their lead ends to form a loop, said apparatus comprising opposed sealing dies constructed and arranged to open and close, two coils of heat sealable strips of insulating material joined together at their lead ends to form a loop, a reciprocating feed means including a feed finge engageable with the loop and operable upon the advance stroke of the feed means to position uncoiled portions of the strips in overlapping relation between the sealing dies, means for actuating said finger at the end of the advance stroke to spread the strips so as to enable a series of spaced terminals to be inserted and positioned in spaced relation between the strips, clamping means to hold the strips against displacement during retraction of said feed means and finger, said sealing dies being constructed so as to clamp spaced areas of the strips together between adjacent terminals and bond together the interengaging portions of the strips and thus form insulating sheaths about each of such terminals, and cutters carried by said sealing dies and operable for cutting the strips through the bonded portions thereof so as to sever the sheaths from each other and from the strips.

8. Apparatus for insulating electric terminals comprising opposed sealing dies, one die being mounted on reciprocable die holding means, feed means to position strips of insulating material in overlapping relation between said sealing dies when open, means for locating a series of terminals in spaced relation between said strips, said sealing dies being constructed so as to clamp spaced areas of said strips together simultaneously between adjacent terminals and bond together the interengaging portions of said strips and thus form insulating sheaths about each of such terminals when said dies are closed, and means operable upon bottoming of said die holding means for severing the strips through the bonded portions thereof so as to sever the sheathed terminals from said strips.

9. Apparatus according to claim 8 wherein said feed means removes scrap material from between said sealing dies after the severing operation.

References Cited UNITED STATES PATENTS EARL M. BERGERT, Primary Examiner.

25 T. R. SAVOIE, Assistant Examiner.

Patent No. 3,392,070

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION July 9, 1968 Walter E. Gropp It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, line 20, cancel "positioning"; line 56, after "loop" insert a comma. Column 9, line 9, cancel "a", first occurrence.

Signed and sealed this 16th day of December 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer