US 3760332 A
A connector arrangement for an implantable pacer which allows an electrode plug to be inserted into a pacer receptacle without the need for set screws or the use of protective medical adhesives. The connector includes a pair of spring-loaded collets each within its own retainer for making reliable electrical connections to two plug pins. A gasket is provided for each collet to prevent body fluids from gaining access to it.
Description (OCR text may contain errors)
llnited States Patent ['19] Be'rkovits et al.
' 1 Sept. 18, 1973 PACER CONNECTOR  Inventors: Barouh V. Berkovits, Newton Highlands; Pieter J. Denouter, Marlboro; Edward L. Lewis, Sharon, all of Mass.
[ 73] Assignee: American Optical Corporation,
 Filed: Mar. 9, 1972 211 Appl. No.: 233,069
 US. Cl. 339/66 R, 128/418, 128/419 P,
' 339/75 P, 339/94 R  Int. Cl Hfllr 13/62  Field of Search 339/60, 65, 66,.75, 3 39/94; 128/418,419 P [56 v v References Cited UNITED STATES PATENTS 2,567,727 9/1951 Quackenbush ..339/75R 3,059,208 10/1962 Concelman 339/65 3,127,230 3/1964 Marquis'et al 339/65 3,701,084 10/1972 Gomez 339/75 M Primary Examiner-Joseph H. McGlynn Attorney-William C. Nealon et al,
57 ABSTRACT A connector arrangement for an implantable pacer which allows an electrode plug to be inserted into a pacer receptacle without the need for 'set screws or the use of protective medical adhesives. The connector includes a pair of spring-loaded collets each within its own retainer for making reliable electrical connections to two plug pins. A gasket is'provided for each collet to prevent body fluids from gaining access to it.
9 Claims, 4 Drawing Figures 1 PACER CONNECTOR This invention relates to arrangements for connecting electrode plugs to implantable pacers, and more particularly to pacer connectors which do not require the use of set screws or protective adhesives.
An implantable pacer, as supplied to the physician, is a self-contained unit having at least one female receptacle into which a two-pin male plug must be inserted during the implantation procedure. Encapsulated leads are extended from the pins to respective electrodes whichare implanted in the patients heart. For proper pacing, it is essential thatafter implantation the plug remainfirmly in the receptacle'and the pins make good electricalcontactwith the connectors in the receptacle. It is also important that there be an hermetic seal, that is, that body fluids not gain access to the interior of the pacer or even to the connectors.
Prior art connectors have generally included set screws for making positive electrical contact with each pin of the electrode plug. A set screw "is provided for each pin, and the screw head is turned from outside the pacer to make contact with the respective pin. Quite apart from reliability considerations, this procedure is time consuming and therefore objectionable when carried out during the course of an operation. Moreover, the hole for each set screw provides a path from the connector within the pacer to the exterior of the pacer,
. and body fluids might otherwise flow through the hole even when a set screw is within .it. For this reason, it is the general practice tocover the head of each set screw with a protective medical adhesive,-as is known in the art. The application of a medicaladhesive to each set screw in this manner is both time consuming and not perfectly reliable.
It is a generalobject of our invention to provide a pacer connector arrangement which does not require the use of set screws or protective medical adhesives, and which nevertheless insures reliable electrical contacts and provides an hermetic seal.
In' accordance with the principles of our invention, the receptacle for each electrode plug is provided with two connectors each for operating in conjunction with one of the two plug'pins. Each connector includes a four-pronged collet contained within a respective retainer. The four prongs are configured to definea central'bore into which a plug pin is inserted. At the forward end of each prong there is an internal ridge for making contact with an inserted pin. The four ridges define a bore having an internal diameter which is fifteen thousandths of an inch smaller than the outer diameter of a plug pin. Each collet is held within its retainer such that there is clearance between the exterior of each of theeollet prongs and the internal wall of the retainer. This allows an inserted pin to force apart the four collet prongs; it is the natural tendency of the prongs to return to their normal position that ensures reliable electrical contact between the pin and the prongs.
At the forward end of each collet-retainer pair there is a ring which functions to guide the respective plug pin along the axis of the respective collet. Forward of each guide ring is a gasket which makes a water-tight seal with an inserted plug. Each connector assembly thus consists of a retainer with a central collet, a guide ring and a gasket, and two such assemblies are fixed within the pacer receptacle into which a two-pin electrode plug is inserted. As is known in the art, a lockpin is used to securely position the plug within the pacer receptacle. (The connectors function to make electrical contact between the plug pins and the pacer circuitry, and are not designed to mechanically retain the plug in place.)
Further objects, features and advantages of our invention will become apparent upon consideration of the following detailed description in conjunction with the drawing, in which:
FIG. 1 depicts a type of pacer electrode plug and leads in current use together with a mechanical lockpin used to secure the plug in place within a pacer receptacle; FIG. 2 is an exploded view of of our invention;
FIG. 3 is a cross-sectional view of the assembled connector element of our invention together with the guide ring and gasketused with it in a pacer; and
'FIG. 4 is a view similar to that of FIG. 3 but shows the connector and associated elements in a pacer with the plug of FIG. I inserted in it.
Plug and leads 10 of FIG. 1 is of a conventional type and is made of silicone rubber. There are four ridges 24 around plug 16 and a larger ridge 28 toward its rear. From the rear of the plug two encapsulated leads 12 extend to electrodes (not shown) which are connected to the. heart tissue during implantation. The leads extending through plug 16 to pins 20 which are embedded in plug projections 18.
The plug is provided with a through-hole 22, into which a retaining lockpin 26 can be passed. It is conventional practice for a pacer to have abore both above and below the plug receptacle so that after a plug is inserted into it, a pin such as 26 can be passed through the plug and held in the bores in the epoxy material used to pot the pacer circuit. It is the lockpin which mechanicallyholds the plug in place with a tight fit. The top of pin 26 is shown with a ridge so that the pin can be gripped with a lockpin tool as is known in the art for inserting it into or removing it from the pacer. 7
FIG. 2 is an exploded view of the elements which comprise each connector (exclusive of the associated guide ring and gasket). Retainer 30 is simply a block of conductive metal, such as stainless steel, having'a long large-diameter bore 34 and a shorter smaller-diameter bore 36. The retainer is soldered to a nickel ribbon 32. It is the nickel ribbon which is actually mounted onthe pacer circuit board, with the ends of the ribbon being folded over and soldered to the board as is known in the art. The collet 38 has a'central bore (of varying diameters) extending all the way through it as will be described in detail below. Along most of the length of the collet there are four slits which define four forwardly extending prongs. A plug 40 is provided for insertion into the rear of the collet bore to seal it, as will be described below. .The collet and the collet plug are also made of conductive material such as stainless steel. (The vplug is really an integral part of the collet; the connector can be thought of as a two-piece element, namely, a collet and aretainer. The plug is separate from the rest of the collet only because it is easier to manufacture the collet from two separate pieces, as will be described below.)
Referring to FIG. 3, it is apparent that collet 38 can be made from a solid cylindrical section of stainless the connector element steel as follows. First, a hole is drilled through the cylinder with a diameter equal to that defined by the inner dimensions of the four ridges 58. Then a tapered bore 48 is formed in the forward end of the collet, and the bore in the rear of the collet is drilled to have a larger diameter, the final bore wall being shown by the numeral 46. Thereafter, a still larger diameter hole is drilled at the far rear of the collet, this bore being shown by the numeral 56. In the last step, the slots 52 are cut at 90 intervals from the forward edge of the collet along most of its length. The result is a cylindrical section at the rear of the unit from which four prongs extend, with a bore of varying diameters extending through the unit.
Collet plug 40 is cylindrical in shape and has a small diameter section 40a and a large diameter section 40b. The collet plug is inserted into the rear of the collet and is secured by a friction fit. The only reason for providing a small-diameter section 40a is to allow simple initial insertion of the plug into the collet bore since the small end of the plug is easily inserted as a result of the loose fit. It is the rear section 40b which closes off the rear of the collet. Since the entire connector unit, after mounting on a circuit board, is potted in an epoxy compound, it is desirable that none of the liquid epoxy material flow through the rear of the collet into the central bore into which a plug pin must later be inserted. Plug 40 seals off the rear of the collet so that the epoxy material, during the conventional potting process, cannot gain access to the interior of the connector unit.
The collet, with its rear plug, is then inserted into retainer 30. This is accomplished by squeezing the four prongs together and inserting the tips of the prongs into the small-diameter bore end of the retainer. The collet is pushed all the way in until it is in the position shown, with the rear end of the collet being flush with the rear end of the retainer and the forward end of the prongs extending slightly forward of the forward edge of the retainer. Although the rear of the collet and retainer are fixed together, it is apparent that the prongs 54 can be spread slightly outwardly within bore 34 of the retainer. If this is accomplished, for example, by the insertion of a pin whose diameter is slightly larger than the inner diameter defined by ridges 58, then the natural tendency of the prongs will be to spring inwardly, and the prongs will thus tightly grip the pin.
At the forward end of the collet and its retainer there is positioned a guide ring 62 which is preferably made of Teflon. The rear of the guide ring has a large diametcr bore 68 which fits over the forwardly extending prongs 54, with the rear of the guide ring resting against the forward face of the retainer. The central bore 66 of the guide ring has a diameter equal to that of the forward end of conical bore 48. The forward end of the guide ring is provided with an enlarged tapered bore 64. The purpose of the guide ring is to guide a pin to a position which is central to all four of the collet prongs. Even ifthe pin is not inserted into the pacer receptacle in a position which is aligned perfectly with the central axis of the collet, the pin is guided by guide ring 62 until the forward end of the pin is along the central axis of the collet. (The guide ring is properly aligned with the collet and its retainer because, as will be described below, the guide ring is inserted into the pacer receptacle and is retained in the proper position by the walls of the receptacle.)
Forward of the guide ring there is provided an O ring or gasket 80. The gasket has a bore whose inner wall fits over the forward end of guide ring 62. The gasket has a plurality of internal ridges 84 which serve to grip a projection 18 on plug 16. It is into end 86 of the gasket that a pin 20 and a projection 18 are inserted in the final assembly steps to be described below.
FIG. 4 depicts a connector assembly within a pacer and a plug 16 held in place in the pacer receptacle, It is conventional practice to mount a pair of connectors on a circuit board and to then pot the overall pacer circuit (including the batteries) in an epoxy compound. (although not shown, it is also conventional practice to cover the final potted unit with a silicone rubber boot.) It is during the molding process that the plug receptacle is formed. The inner wall 96 of the receptacle has a shape to accept plug 16 of FIG. 1. The molded receptacle includes two large-diameter sections for containing two gaskets 80. After the pacer circuit is potted and the epoxy material has hardened, a guide ring 62 is placed forward of each of gaskets 80, and the two assemblies are then pushed into the receptacle. Each rubber gasket is compressed as it is pushed in and then expands into the respective recess in the receptacle provided to contain it. In this position, as shown in FIG. 4, each guide ring 62 is held centrally disposed around the respective connector element and the guide ring and the gasket are held securely within the receptacle. The gasket cannot slide out of the receptacle by virtue of a wall 98 in the epoxy package; when a gasket is pushed all the way into the receptacle it expands into the recess as shown in the drawing. An even more secure fit can be obtained by placing some adhesive around each receptacle recess prior to insertion of the respective guide ring and the gasket.
During implantation of the pacer, all that is required of the physician to effect a connection of plug 16 to the pacer is to insert the plug as shown in FIG. 4 and, while the plug is pushed in, to insert lockpin 26. During the potting process, a hole 94 is formed above the receptacle and a tapered bore is formed below it. The lockpin is simply forced through the upper hole and the hole 22 in the plug into the bottom tapered bore 92. In this position, the plug is held tightly up against the forward ends of gaskets 80. The plug is held securely, and with a water-tight fit, within bore 96 by virtue of its ridges 24. Each of plug projections 18 is held securely within the internal ridges 84 of a respective one of the two gaskets, and the respective pin 20,-after being guided by guide ring 62 into a respective connector, is held there by virtue of the fact that the four connector prongs are bent outwardly slightly because the diameter of the pin is slightly larger than the diameter defined by ridges 58. There is no need for a set screw for each pin because a perfectly reliable electrical contact is made between the prongs of each collet and the respective pin. An hermetic seal is achieved because of the manner in which each of gaskets makes a water-tight seal around a respective one of plug projections 18. All that v (with two connectors in each) are provided so that two electrode plugs can be coupled to the pacer in order to provide atrial as well as ventricular stimulation. Such a pacer is provided with two female receptacles with a single lockpin being used for insertion through the two receptacles and the two contained electrical plugs. The present invention is applicable to such a pacer, with each receptacle and its contained elements being made as shown in the drawing. Thus it is to be understood that numerous modifications may be made in the illustrative embodiment of the invention and other arrangements may be devised without departing from the spirit and scope of the invention.
What we claim is:
l. A pacer connector arrangement for connecting an electrode plug having two pins extending from projections thereon to a pacer circuit comprising a pair of connector assemblies, each for coupling signals between the pacer circuit and a respective plug pin, each of said connector assemblies having a multi-pronged collet embedded in the pacer, each prong thereof having a ridge projecting toward the central axis of the collet with the radial spacings of the ridges being such that when a pin is inserted therebetween the prongs are forced slightly outwardly, a guide ring disposed around the forward end of said multi-pronged collet for guiding a pin inserted therethrough along the axis of said collet, and a gasket disposed forwardly of said guide ring and having an internal configuration for effecting a watertight seal with a respective one of the pin projections on said plug, both of said collets and their associated guide rings and gaskets being contained at the rear of a receptacle in the pacer into which said plug is insertable, and means for mechanically locking said plug in said receptacle.
2. A pacer in accordance with claim 11 further including a retainer disposed around each of said multipronged collets, the rear of each collet being fixed to the rear of its respective retainer and each of said retainers providing clearance around the retained collet prongs for allowing slight outward movement thereof when a plug pin is inserted therein.
3. A pacer in accordance with claim 2 wherein the rear end of each retainer and its retained collet is closed.
3. A pacer in accordance with claim 3') wherein each of said guide rings includes a tapered bore having its smaller diameter end adjacent to the forward end of the respective collet.
5. A pacer in accordance with claim wherein each of said gaskets includes a plurality of internal ridges for securing a respective one of said plug projections.
6. A pacer in accordance with claim 2 wherein each of said guide rings includes a tapered bore having its smaller diameter end adjacent to the forward end of the respective collet.
'7. A pacer in accordance with claim 6 wherein each of said collets extends slightly forward of its respective retainer and the respective guide ring bears against the forward end of the retainer and encloses the projecting portions of the prongs extending therefrom.
3. A pacer connector arrangement for connecting an electrode plug pin to a pacer circuit comprising a connector assembly for coupling signals between the pacer circuit and the plug pin, said connector assembly having a multi-pronged collet embedded in the pacer, each prong thereof having a ridge projecting toward the central axis of the collet with the radial spacings of the ridges being such that when a pin is inserted therebetween the prongs are forced slightly outwardly, means disposed forward of said multi-pronged collet for guiding a pin inserted therethrough along the axis of said collet and for effecting a water-tight seal with said plug, said collet and said forwardly disposed means being contained at the rear of a receptacle in the pacer into which said plug is insertable, means for mechanically locking said plug in said receptacle, a retainer disposed around said multi-pronged collet, the rear of said collet being fixed to the rear of said retainer, said retainer providing clearance around the retained collet prongs for allowing slight outward movement thereof when a plug pin is inserted therein, and wherein the pin extends from a projection of said plug, and said forwardly disposed means includes a plurality of internal ridges for securing said plug projection and effecting a watertight seal therewith.
d. A pacer connector arrangement for connecting an electrode plug pin to a pacer circuit comprising a connector assembly for coupling signals between the pacer circuit and the plug pin, said connector assembly having a multi-pronged collet embedded in the pacer, each prong thereof having a ridge projecting toward the central axis of the collet with the radial spacings of the ridges being such that when a pin is inserted therebetween the prongs are forced slightly outwardly, means disposed forward of said multi-pronged collet for guiding a pin inserted therethrough along the axis of said collet and for effecting a water-tight seal with said plug, said collet and said forwardly disposed means being contained at the rear of a receptacle in the pacer into which said plug is insertable, means for mechanically locking said plug in said receptacle, a retainer disposed around said multi-pronged collet, the rear of said collet being fixed to the rear of said retainer, said retainer providing clearance. around the retained collet prongs for allowing slight outward movement thereof when a plug pin is inserted therein, and wherein said collet extends slightly forward of said retainer and said forwardly disposed means bears against the forward end of the retainer and encloses the projecting portions of the prongs extending therefrom.
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