Electric-pneumatic Junction

Abstract

A junction is described facilitating connection and disconnection of a first pneumatic line carrying within it one or more electrical conductors to and from a second pneumatic line carrying within it corresponding conductors by means of a connecting plug insertable therein, the junction having contacts mating with corresponding contacts on the connector, an air passage communicating with the first line and a releasable seal engaging the connector which in turn has not only the contacting surfaces electrically connected to the conductors of the second line but also an air passage communicating with the second line.

Description

This invention relates to electric-pneumatic systems. A patient's intracranial pressure may be monitored using a pressure-actuated switch implanted inside the patient's skull, with attached external pressure-measuring and current-measuring devices. To use this method to monitor intracranial pressure, air and electrical connections must be made to the implanted switch. The lines to be connected are typically in the form of fine wires carried within small plastic tubing (for example, 0.028 inch inner diameter and wall thickness of 0.009 inch). In clinical practice, such connections must be made immediately after the switch has been implanted, while the patient is still in the operating room. When the patient is moved from room to room during the postoperative period, it may be necessary for different persons to disconnect and connect the switch several times.

In a system to monitor intracranial pressure by the method described, an implantable pressure-actuated switch (such as the Numoto switch) is known; the ohmeter and manometer are well known in various forms; and suitable connectors are known. However, the novel junction described herein for use with such switch, ohmeter, manometer, and connector, greatly facilitates connecting and disconnecting the elements in simpler and more reliable fashion.

It is therefore an object of this invention to provide a junction that makes possible rapid and secure connections between an implantable pressure-actuated switch and the necessary air and electrical lines without directly handling the individual wires and tubing.

It is another object of the invention to provide a junction that may be conveniently operated by persons wearing surgical gloves.

It is also an object of this invention to provide a junction that may be easily and conveniently operated by persons without special skill or experience, thereby contributing to the patient's safety.

In general, the invention features a junction for use as part of an electric-pneumatic system in connecting and disconnecting a first pneumatic line carrying within it one or more electrical conductors to and from a second pneumatic line carrying within it corresponding conductors and having a terminal connector operatively connected thereto provided with a protruding portion having a passage communicating with its pneumatic line and electrical contact surfaces connected with its corresponding conductors. The junction comprises a hollow body defining an internal chamber and having a connecting portion at one end adapted for sealing connection to the first line, such connecting portion having a duct establishing communication between the chamber and the first line and accommodating leads from the conductors carried within said line. The chamber has an entrance at the other end for receiving the protruding portion of the connector, contains electrical contacts, corresponding in number to the number of electrical conductors of the system, the contacts being adapted for attachment to the leads. These contacts are resiliently mounted within the chamber and arranged to engage the contact surfaces of the connector when the latter is inserted into said junction. The junction also includes sealing means for creating a releasable airtight connection between the chamber and the inserted portion of said connector, the sealing means preferably comprising an apertured cap threaded to the hollow body and a resilient seal which is compressed against the protruding portion of the connector when the cap is tightened.

In preferred embodiments, the junction and connector are adapted to be axially aligned when they are joined, the air lines and chamber being located centrally within the connector and junction, and the several contacts of the junction have contacting portions which are axially spaced from each other and correspond with similarly spaced contact surfaces of the connector. The contacts of the junction are resilient, and are biased inwardly through the wall of the chamber. The electric terminals and the air lines of connector and junction are automatically joined when the two parts are joined, independently of the relative angular position of the two parts, and without the necessity of handling the individual lines or terminals.

Other objects, features and advantages will appear from the following description of a preferred embodiment of the invention, taken together with the annexed drawings, in which:

FIG. 1 shows the junction in use, the junction and associated tubing being greatly enlarged in scale and the indicating equipment being shown somewhat diagrammatically;

FIGS. 2 and 3 are longitudinal sectional and plan views, respectively, of the switch;

FIG. 4 is a plan view of the connector;

FIG. 5 is a cross section on an enlarged scale of the connector, taken along the line 5--5 of FIG. 4;

FIG. 6 is a plan view of the junction;

FIG. 7 is a longitudinal cross section of the junction, taken along line 7--7 of FIG. 6;

FIG. 8 shows on a somewhat smaller scale the assembled connector and junction, the junction being shown in longitudinal section.

Referring now to FIGS. 1, 2, and 3, a pressure-actuated switch 10 (such as a "Numoto" switch) is shown implanted within the skull 12 of a patient through a burr hole 14. The switch 10 includes a thin, flat silicone envelope 16; cemented to the inside of flat surface 18 of envelope 16 is a gold electrode 20, forming one pole of a simple on/off switch, the other pole being a similar electrode 22 cemented to the inside of flat surface 24. Electrodes 20 and 22 are connected to leads 26 and 28, which are contained in a vinyl air tube 30.

The intracranial pressure keeps the two gold electrodes 20 and 22 in contact so long as that pressure exceeds the air pressure within switch 10, and an ohmeter 32 will show switch 10 to be closed. To measure the intracranial pressure, the air pressure within switch 10 is raised by the slow injection of antiseptic fluid into the reservoir 34 of manometer 36. When the pressure inside the switch envelope just exceeds the intracranial pressure, sides 18 and 24 of envelope 16 are forced apart, carrying with them the electrodes 20 and 22, and ohmeter 32 shows that the electrical contact has been broken. Small amounts of solution are alternately withdrawn and injected into reservoir 34, causing the electrical contact to close and open. The pressure at which this occurs is read on the manometer 36.

The vinyl air tube 30 from switch 10, containing electrical leads 26 and 28, terminates in a connector 40 (FIGS. 4 and 5), providing a first contact surface 42, a teflon insulator 44, a second contact surface 58, and a steel air tube 50. Connector 40 is symmetric about its axis. Within connector 40, vinyl air tube 30 overlaps and is sealed to the inner end of tube 50. Electrical leads 26 and 28 are led out of tube 50 through a hole 52; lead 28 is wrapped several turns around the outside of tube 50 and soldered thereto. Epoxy cement 54 surrounds the junction of vinyl tube 30 and steel tube 50, and hermetically seals hole 52. Lead 26 is soldered to generally annular steel contact 47, which has a first contact surface 42 which is cylindrical and somewhat reduced in outer diameter, a surface of larger diameter 45 covered by a layer 48 of insulation, and a tapered seating surface 46 between surfaces 45 and 42. Teflon insulator 44 separates contact 47 from contact 57, which carries contact surface 58 and which is in electrical contact with steel air tube 50 and thereby with lead 28. Contact 57 provides a tapered leading surface 59.

The portion of connector 40 extending from seating surface 46 to the exposed end of steel air tube 50 is defined as the protruding portion, and is that part of the connector that is received within the junction. The protruding portion includes a forward portion, defined as the exposed part of air tube 50 extending beyond contact 57, and an after portion of somewhat larger diameter, defined as the portion of connector 40 extending from seating surface 46 through contact 57.

Junction 60 (FIGS. 6-8) has a sealing cap 62, a body 64, and a connecting vinyl air line 66 which leads to the pressure measuring equipment. Cap 62 has a hole 68 in outer end 69 to admit the forwardly protruding portion of connector 40, and is threaded on inner surface 70. The outer surface 71 of body 64 is threaded adjacent the outer end 65 to permit the cap 62 to be attached to body 64. Between end 65 of body 64 and end 69 of cap 62 is an O-ring 72. Body 64 is generally annular. It has a cylindrical inner surface 78 adapted to enclose contact surface 42 of connector, and another cylindrical inner surface 80 adapted to enclose steel air tube 50. Cylindrical inner surfaces 78 and 80 are joined by conical stop surface 92. Resilient contacts 74 and 76, lying axially in spaces 84 and 86, project inwardly through surface 78, and are biased inwardly toward the axis of junction 60. Leads 88 and 90, attached to contacts 74 and 76, respectively, pass through air space 79 and are carried away from junction 60 through air line 66.

In use, to connect junction 60 and connector 40, cap 62 is partially unscrewed to release O-ring 72, whereupon connector 40 is inserted into junction 60, until leading surface 59 of the connector seats against conical surface 92 of the junction. Cap 62 is now tightened to compress O-ring 72 to provide an air seal around connector 40. First contact surface 42 of connector 40 engages terminal 76, while second contact surface 58 engages terminal 74, providing electrical connections, and air tube 50 opens into air space 79, providing an air connection to tube 66. The reverse procedure is followed to disconnect the connector from the junction.

Claims

What is claimed is:

1. A junction for use in connecting and disconnecting a first pneumatic line carrying within it one or more electrical conductors to and from a second pneumatic line carrying within it corresponding conductors and having a terminal connector operatively connected thereto provided with a protruding portion having a passage communicating with its pneumatic line and electrical contact surfaces connected with its corresponding conductors, comprising

a hollow body defining an internal chamber and having

a connecting portion at one end adapted for sealing connection to said first line,

said portion having a duct establishing communication between said chamber and said first line and accommodating leads from the conductors carried within said line

an entrance to said chamber at the other end for receiving the protruding portion of said connector

electrical contacts, corresponding in number to the number of electrical conductors carried in said lines, and being adapted for attachment to said leads, resiliently mounted within said chamber and arranged to engage the contact surfaces of said connector when the latter is inserted into said junction, and

sealing means for creating a releasable airtight connection between said chamber and the inserted portion of said connector.

2. The junction of claim 1 wherein said sealing means comprises

an apertured sealing cap engaging said body and surrounding said entrance, and

a resilient seal between said cap and said body,

said cap being adapted to compress said seal and for creating a releasable airtight connection between said chamber and the inserted portion of said connector.

3. The junction of claim 2 wherein said hollow body defines both an internal chamber and outer chambers corresponding in number to the number of said electrical contacts, and each said electrical contact lies within a said outer chamber with a portion of said contact extending into said inner chamber, said contact being biased inwardly, for engaging a corresponding contact surface of the connector.

4. The combination of the junction of claim 2 with an electric-pneumatic terminal connector operatively connected to said second pneumatic line, and provided with a protruding portion, having

a tube communicating with said second pneumatic line and adapted to communicate with said internal chamber of said junction,

and a plurality of electrical contact surfaces, connnected with corresponding conductors of said second pneumatic line, positioned sequentially externally of said protruding portion, and separated by insulating elements, each said contact surface and each said insulating element extending entirely around the perimeter of said protruding portion.

5. The combination of the junction of claim 3 with an electric-pneumatic terminal connector, operatively connected to said second pneumatic line, and provided with a protruding portion, having

a tube communicating with said second pneumatic line and adapted to communicate with said internal chamber of said junction,

and a plurality of electrical contact surfaces, connected with corresponding conductors of said second pneumatic line, positioned sequentially externally of said protruding portion, and separated by insulating elements, each said contact surface and each said insulating element extending entirely around the perimeter of said protruding portion.

6. The combination of claim 5 wherein

said protruding portion of said connector is generally annular and comprises a forward portion and an after portion of greater outer diameter than said forward portion,

said tube lies centrally within said connector and extends axially within both said after and said forward portions, and

said connector has two electric contact surfaces spaced axially externally of said after portion, said two contact surfaces being separated by an insulator, each said contact surface and said insulator extending entirely around the circumference of said after portion,

said internal chamber of said junction comprises a forward chamber adapted to receive said forward portion of said protruding portion and an after chamber of greater inner diameter than said forward chamber, adapted to receive said after portion of said protruding portion;

said junction has two said outer chambers, and two said resilient electrical contacts each lying within a said outer chamber, the said portions of said two contacts that extend into said internal chamber being positioned sequentially along the axis of said after chamber for contact with said two contact surfaces of said connector.