US3183472A - Unitary rigid wire connectors and method of making wire connections - Google Patents

Description

y 1, 1965 w. s. PAWL 3,183,472

UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONS Filed 001;. 2, 1965 4 Sheets-Sheet l m \m\\\\ v 2 IA/I E/VTOR Mafia KW May 11, 1965 w, s, P w 3,183,472

UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONS Filed OCT.- 2, 1963 4 Sheets-Sheet 2 RANGE OF WIRE SIZES LARGEST WIRE INSULATION LARGEST WIRE 8| SMALLEST WIRE INSULATION SMALLEST WIRE RANGE OF WIRE INSULATION FIG. IO H6 5 4 NWENTOR May 11, 1965 w. s. PAWL 3,183,472

UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONS Filed Oct. 2, 1963 4 Sheets-Sheet 3 74 FIG. 6 6 e4 54 //VVE/YTUR FIG. ll im May 11, 1965 w. s. PAWL 7 UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONS Filed Oct. 2, 1963 4 Sheets-Sheet 4 United States Patent 3,183,472 UNITARY RIGID WIRE CONNECTORS AND METHOD OF MAKING WIRE CONNECTIONS Walter S. Paw], 2844 Powder Mill Road, Adelphi, Md. Filed Oct. 2, 1963, Ser. No. 313,282 6 Claims. (Cl. 339-97) This invention relates to improvements in simple wire connector units of the type illustrated in my joint application with Stephen N. Buchanan, Ser. No. 131,958, filed August 8, 1961, for Rigid Unitary Wire Connectors.

The object of this invention is to make a simple onepiece conducting connector element having means for receiving a plurality of wires while breaking through their insulations to provide high pressure contacts between the element and each wire.

A further object is to provide an insulator block around this connector element of simple form having a recess for the exposed ends of the wires.

A further object is to provide a closure cap of insulating material to close said recess and hold said wires in said connector element.

A further object is to provide an inserting tool head inside said cap for pressing said wires into said element, one at a time and to hold said wires in said element.

A further object is to provide a waterproof seal between said block and said closure cap.

Other and more specific objects will become apparent in the following detailed description of some forms of connectors made in accordance with the present invention as illustrated in the accompanying drawings, wherein:

FIG. 1 is an enlarged vertical sectional view of a simple rectangular block form of connector unit with a cap shown in exploded position, the section being taken on the line 11 shown in FIG. 2,

FIG. 2 is a vertical sectional view of the block taken on the line 22 of FIG. 1, with the cap closing the top of the block,

FIG. 3 is a plan view of the block without the cap,

FIG. 4 is an enlarged sectional view of a cylindrical block form of connector unit with a closure cap in exploded position, the section being taken on the line 4l4 of FIG. 5,

FIG. 5 is a vertical sectional view taken on the line 55 of FIG. 4,

FIG. 6 is an enlarged sectional view of still another block form of connector unit with a cylindrical closure cap for completely sealing the connector unit, with a twist lock means for locking it in place,

FIG. 7 is a sectional view taken on the line T -"'7 of FIG. 6,

FIG. 8 is an enlarged side view of a wire inserting tool,

FIG. 9 is a plan view of this tool,

FIG. 10 shows the comparative sizes of wires and their insulations within a range of sizes for which the connector is made,

FIG. 11 is a sectional detail view taken on the line li -11 of FIG. 8, and

FIGS. 12 and 13 illustrate a simple cap type connector with twist lock means for easy assembly of the cap over the ends of the connected wires.

The simple connector element 12 may be identical for all the block forms as shown. The element is primarily circular, having segments cut oil on opposite sides 14 and a vertical radially extending slot 16 between these sides, having smooth parallel walls flaring out at the periphery to pointed ridges 18 spaced approximately a distance equal to the diameter of the insulation or" the smallest size wire in the range of sizes for which the connector is made, the parallel portions of the walls being spaced not more than the smallest size wire. The comparative sizes of wires and their insulations within the range of sizes that may be used in this connector are indicated in FIG. 10. This range may be selected as #12 to #16, #18 to #22, etc., as may be desired, and for which the slot may be suitably designed.

The block form Zil, FIGS. 1 and 2, may be a molded plastic insulator material of suitable electrical characteristics, and has a large rectangular recess 22 in its upper portion, in one side of which the connector element 12 is mounted and extends downwardly into a smaller recess 24 in the lower portion, with a force lit. The bottom of this recess 2 5 is vented by a small bore 26, to facilitate assembly of the element 12 in this block.

The block 26 has -a guide slot 28 coaxial with the slot 16, and open at the top of the block to receive and guide the insulated wire over the slot 16, and to prevent bending strain on the inserted wires at the contact areas when the leads are accidentally pulled to one side or the other of the slot.

For purposes of illustration, three different sizes of wires 3%, 31 and 32 are shown in cross section in the slot 16 of the connector element in FIG. 1, 350 being the smallest size and 32 the largest, for which the connector is designed. The respective terminal ends 33, 34 and 35, of these wires extend into the large recess 22, and may be sealed oil by a closure cap 36 to prevent accidental shorts with external connections in proximity to the connector block.

The closure cap may have a plug portion 33 fitting snugly in the top of the recess 22 and forming a tool head portion ill, which may be used to install the wires as well as hold them against accidental loosening after they are installed.

A tool such as shown in FIGS. 8 and 9 may be used to install the wires in any of these connector units. The tool has a pair of handles 42 and 44, pivoted at one end and normally biased to spreading position by a spring 46. The other ends of the handles are provided with a fiat bearing head 48 on the lower handle 44 to place under the connector block, and an inserter head 50 on the upper handle 42 to place over the Wire in the open end of the guide slot 23, the thicker portions 52 of the inserter head being positioned to straddle the connector element and the thin intermediate portion 54 being held directly over the slot 16. By firmly squeezing the handles of the tool, the Wire is pushed in through the flared end of slot 16, where the pointed ridges break into the insulation on the wire and the flared slot wall-s push it away from the contacts as the bare wire enters the paral lel wall portion of the slot 16, and its circular periphery is somewhat flattened by the convergent Walls of the slot toward the bottom of the flared end thereof. The separated portions of the insulation around these contacts hug the adjacent slot wall portions and seal the contacts against moisture and oxidation. The smooth slot walls prevent scoring of the wire, merely squeezing it, so that it is not weakened but merely deformed in cross section sassy/2 by a slight flattening to provide a high pressure contact area on opposite sides of the wire with the smooth slot walls.

The slot walls being rigidly held parallel, and being smooth, the deformation pressure exerted by the walls against the opposite sides of the wire is not relieved but is substantially retained even after the wire is moved to the bottom of the slot. This high contact pressure eliminates any possibility of introducing undesirable resistance in the connector circuit even at high loads.

The highest pull-out strength is also maintained in this type of connector, because the cross-sectional area, while it is deformed by flattening at the contacts, is not reduced; nor is the wire weakened by brittleness due to vibration or excessive heating as in soldered connections, or where no guide slots are used to dampen vibrations at the contacts in vibrational environments.

In slot type connectors of the prior art, the contact pressure was obtained either by wedging in a rigid tapered slot or resilient pronged slot, neither slot being adapted to receive more than one wire. Some slots with substantially parallel side walls have been used, but no attempt has ever been made to compress the wire into these slots, nor to provide smooth walls for these slots to prevent scoring of the wire, which relieves any deformation compression to which the wire might be subjected before entering such a slot. The present connector element is unique in that it retains a high contact pressure on a plurality of wires of any size within a predetermined size range and does not weaken them by scoring or cutting of any kind, while at the same time it prevents weakening due to vibration.

By using a water tight cap, with a resilient sealing plug 56 over the wire in the upper part of the guide groove 28, the present connector is made highly resistant to extreme vibration and shocks as well as water tight.

A circular block form 6% for the connector element 12 is shown in FIGS. 4 and 5, wherein the same arrangement of large and small recesses 62 and 64 is used for the wire terminal ends 33, 34 and 35 and the lower end of the connector element 12, respectively. The closure cap 66 is similar to cap 36 but is curved to conform with circular periphery of the block 60. A complete seal of the block is attained in the same manner by using a resilient sealing plug 56 to fill the upper part of the guide groove 28 over the wire leads stacked in the lower part of the groove 28, when the cap 66 is plugged into the recess 62 tightly. The closure caps are preferably molded of a somewhat resilient insulator plastic material.

A modified form of the circular block form is shown in FIGS. 6 and 7, wherein the block 67 has segments cut off at opposite sides leaving thin side walls 68 and 7d, the large recess 72 being open at the back as well as at the top. A cylindrical closure cap 74 is used, having segmental portions '76 at its open end to slide over the straight sides 68 and 70 of the block when installing the cap over the block, and when the cap is pushed against the back end of the block, the segmental portions 76 clear the front face of the block so that by turning the cap, it may be locked over the block to completely seal it and at the same time to wedge the inner edge of one of the portions 76 over the upper wire 33 to hold all the wires against any accidental loosening by continuous vibration or otherwise. This turning may be facilitated by providing raised portions '78 and 80 on the face of the block and on the back of the cap respectively. Either of these raised portions may be formed to provide an inserting tool 82, as shown in FIG. 7, for pushing the wire through the entrance to the slot in the connector.

This same type of tool head 32 is shown as Sti at the end of the upper handle in the inserting tool of FIGS. 8 and 9, and in cross section in FIG. 11. Obviously, the tool could be made in many other simple forms, as e.g. both handles 42 and 44 could be made of one continuous curved piece of spring material instead of having a hinge and the biasing spring 46.

In FIG. 10 the inner circle and the intermediate circle show the comparative range of sizes of wire in cross section that may be readily used in the size of slot illustrated, and range of sizes of the insulation cross section area may be between that of the intermediate circle for the smallest wire and the outer circle for the largest wire that it may be feasible to use in this connector slot.

A suitable material for this connector has been found to be a Phosphor bronze of superior hardness and good conductivity and strength. However, any other materials having good electrical conductivity, required strength to maintain rigidity under the operative stresses and other suitable characteristics, may be used. The same is true of the block and cap materials, which may be selected from a large number of insulating materials having the proper electrical and mechanical characters for best results.

Another more simple modification of this connector is shown in FIGS. 12 and 13. In this case the connector element 90 does not have any insulating support block, but is simply insulated after the wires are inserted, by a cap 84 of insulating material, which has an inserting tool head 86 on the outside, and inner segmental locking flanges 88. The cap thus serves as a tool for inserting the wires in the connector element, and then as an insulating cover for the element. These flanges may be provided with bumps 92 near their ends as shown, so that the cap may be locked by turning in either direction until one of these bumps reaches the slot and catches over the side wall of the slot entrance 94. The ends of the wires 33, 34 and 35 will tend to push the cap olf and hold it in locked position, but by pressure on the cap it may be turned to release position and removed. A skirt 96 of suitable length beyond the flanges 88 may be provided to protect the connector element from coming into accidental contact with adjacent conductive materials to produce a short.

It has been found that a substantially sharp ridge 98 at each side of the entrance to flared portion of the slot 1&0 of the connector element 90, where the flaring side walls of the slot meet the periphery of the element 90, is suflicient to start the break into the insulation, after which the break is completed depthwise of the insulation by the squeezing effect between the wire and the slot wall surfaces, as the wire is forced through the flared portion of the slot, and the line contact first made between these convex surfaces completes the break through the insulation, which is then squeezed away from the contact surfaces as they are enlarged from the initial line contacts to flat areas under compression between the parallel sides of the slot. Ridges 98 should be spaced to receive the largest size wire in the range for which the slot is designed, so that the initial line contacts between the wire and flared portions of the slot sides will fall inside the ridges 98 and the wire will not be scored by these ridges. At the same time this spacing of the ridges should close enough that the ridges may break into .the outer edges of the insulation of the smallest size wire in the range for which the slot is designed, as the insulation is squeezed outwardly over these ridges when the wire is pushed into the flared entrance between them.

While only a single slot connection element is illustrated, it is to be understood that more than one slot may be used in the same element, the total length of their parallel sided portions providing the capacity for the number of wires desired to be joined together. On the other hand, for terminals requiring only a single wire connection, only a short single slot is required.

The connector slots illustrated are all of the type that open at an outer edge of the connector element. This makes it diflicult to maintain rigidity at the outer end of a long slot without making the connector element unduly wide. By cutting a small opening in the connector element large enough to freely pass an insulated wire through it, and extending the slot or slots from the inner edge of this opening, the outer ends of sides of these slots are more rigidly supported against spreading by the arch of the material around the opening. Thus, much less overall width of the connector element is required. This may be an important space-saving feature in multi connector or terminal block structures or other places where screw type terminals are too bulky.

The present connector elements are not only space savers but are also cheaper to make because of their simplicity, and save installation time because no stripping or other preparation of the wires is required. They are simply pushed into the slot with a single stroke and the connection is made, the insulation being automatically pierced and removed from the points of contact with the sides of the slot, which flatten the wire at these points, and the joints are sealed by the remaining insulation around them.

Many obvious modifications in the form and details of structure of the connector elements, blocks and cover caps may be made without departing from the spirit and scope of the present invention, as defined in the appended claims.

What is claimed is:

1. A rigid unitary connector element of hard conductive material adapted to connect at least one wire thereto and having at least one slot with smooth flat parallel sides spaced less than the diameter of wire sizes which it is adapted to receive and hold in compression, between its parallel sides, said sides being flared at one end of the slot to receive and smoothly compress the wires as they are forced into the slot,

each slot having a flared entrance formed to receive and flatten the wire as it passes therethrough into said slot and to rupture and remove any insulation on the Wire at the flattened pressure contacts with said parallel sides,

said element being shaped generally like a round disc with a single slot extending diametrically from its edge and with segments cut :oif on opposite sides of the slot parallel thereto,

said slot being long enough to receive at least two wires to provide an electrical connection between them.

2. A rigid unitary connector element as defined in claim 1, and a hollow insulating block having a pocket in the bottom at one side of said hollow in which said element is frictionally mounted, the slot entrance being at the top and below the top of the block, the adjacent side of the block having a guide slot extending from the top of the block to the bottom of the slot in the connector clement adapted to form a guide for the wire leads of any inserted wires extending outwardly of said block and having their ends in said hollow.

3. A rigid unitary connector element of hard conductive material adapted to connect at least one wire thereto and having a slot with smooth flat parallel sides spaced less than the diameter of wire sizes which it is adapted to receive and hold in compression between its parallel sides,

said sides being smoothly flared at one end of the slot to a gap wider than the largest of said wire sizes to receive and smoothly compress the wires as they are pushed into the slot,

said connector element being shaped generally like a round disc with said slot extending diametrically from its edge and with segments cut off on opposite sides of said slot and parallel thereto,

said slot being long enough to receive at least two wires to provide an electrical connection between them,

a hollow insulating block open at the top and having a pocket in the bottom at one side of said hollow in which said element is frictionally mounted,

the slot entrance being at the top and below the top of the block,

the adjoining side of the block having a guide slot extending from the top of the block to the bottom of the slot in the connector element adapted to form a guide for the wire leads of any inserted wires extending through said guide slot outwardly of said block, said hollow being large enough to accommodate the inner ends of said wires, and

a cover cap having a plug portion frictionally fitting into the top of said hollow block and a resilient plug for sealing the guide slot above the wires mounted therein, whereby the connector block may be completely sealed against moisture and oxidation as well as arcing over from the connector element and exposed ends of the wires in the hollow of said block to adjacent conducting materials, especially at high altitudes where flash over would occur through any open cracks in the guide slot seal because of the reduced dielectric strength in the atmosphere which has little or no air.

4. A rigid unitary connector element of hard conductive material adapted to connect at least one wire thereto and having a slot with smooth flat parallel sides spaced less than the diameter of Wire sizes which it is adapted to receive and hold in compression between its parallel sides,

said sides being smoothly flared at one end of the slot to a gap wider than the largest of said wire sizes to receive and smoothly compress the wires as they are pushed into the slot,

said connector element being shaped generally like a round disc with said slot extending diametrically from its edge and with segments cut off on opposite sides of said slot and parallel thereto,

said slot being long enough to receive at least two wires to provide an electrical connection between them,

a hollow insulating block open at the top and back and having a pocket in the bottom at the front of the hollow in which pocket said element is frictionally mounted,

the slot entrance being at the top and below the top of the block,

The adjoining side of the block having a guide slot extending from the top of the block to the bottom of the slot in the connector element adapted to form a guide for the wire leads of any inserted wires extending through said guide slot outwardly of said block,

said hollow being large enough to accommodate the inner ends of said wires,

said block having thin vertical walls extending back from the straight edges of said connector element, the top and bottom of the block conforming to the otherwise circular shape of the connector element, the back of the hollow portion of the block being open as Well as the top, and

a cylindrical cover cap of insulating material adapted to be mounted over the entire block from the back and having inner segmental flanges at its outer end corresponding to the spaces in the cap on the opposite parallel sides of the block, for turning over the front of the block to lock the cap thereon.

5. A rigid unitary connector element of hard conductive material adapted to connect at least one wire thereto and having a slot with smooth flat parallel sides spaced less than the diameter of wire sizes which it is adapted to receive and hold in compression between its parallel sides,

said sides being smoothly flared at one end of the slot to a gap Wider than the largest of said wire sizes to receive and smoothly compress the wires as they are pushed into the slot,

said connector element being shaped generally like a round disc with said slot extending diametrically from its edge and with segments cut off on opposite sides of said slot and parallel thereto,

said slot being long enough to receive at least two wires to provide an electrical connection between them, and

ii a cylindrical insulating cap having inner segmental References Cited by the Examiner flanges corresponding to the segmental cut out por- UNITED STATES PATENTS trons of said connector element, for shpplng over the a back of said element and turning it to lock said 21333266 11/43 33995 flanges over the front of the circular portions of 5 2,501,137 3/50 oorFgllsen 339 95 said element. 3,012,219 12/61 Levin et a1. 33998 A cc1 1nnect0r ellement and cap asddefined in cliaimbS, FOREIGN PATENTS sal cap aving a s irt portion exten ing ontwar y e- 615 737 1/49 Great Britain t yond said flanges to protect the front of sald connector 659316 10/51 Great Britain element against accidental contact with outside conduct- 10 ing materials. JOSEPH D. SEERS, Primary Examiner.

Claims (1)

1. A RIGID UNITARY CONNECTOR ELEMENT OF HARD CONDUCTIVE MATERIAL ADAPTED TO CONNECT AT LEAST ONE WIRE THERETO AND HAVING AT LEAST ONE SLOT WITH SMOOTH FLAT PARALLEL SIDES SPACED LESS THAN THE DIAMETER OF WIRE SIZES WHICH IT IS ADPATED TO RECEIVE AND HOLD IN COMPRESSION, BETWEEN ITS PARALLEL SIDES, SAID SIDES BEING FLARED AT ONE END OF THE SLOT TO RECEIVE AND SMOOTHLY COMPRESS THE WIRES AS THEY ARE FORCED INTO THE SLOT, EACH SLOT HAVING A FLARED ENTRANCE FORMED TO RECEIVE AND FLATTEN THE WIRE AS IT PASSES THERETHROUGH INTO SAID SLOT AND TO RUPTURE AND REMOVE ANY INSULATION ON THE WIRE AT THE FLATTENED PRESSURE CONTACTS WITH SAID PARALLEL SIDES, SAID ELEMENT BEING SHAPED GENERALLY LIKE A ROUND DISC WITH A SINGLE SLOT EXTENDING DIAMETRICALLY FROM ITS EDGE AND WITH SEGMENTS CUT OFF ON OPPOSITE SIDES OF THE SLOT PARALLEL THERETO, SAID SLOT BEING LONG ENOUGH TO RECEIVE AT LEAST TWO WIRES TO PROVIDE AN ELECTRICAL CONNECTION BETWEEN THEM.

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