Patent Application
20110297526
1. Field of the Invention
The present invention relates to a pneumatically actuated switching device in a pneumatic actuator system for a patient call system. More specifically, the present invention relates to an interchangeable snap fit air connector assembly for a pneumatically actuated switching device connected to a pneumatic actuator of a patient call system.
2. Description of the Prior Art
Hospitals, and other patient-care institutions, frequently provide patient call systems wherein a patient may activate a signal to a central station, such as a nurse's station, to summon assistance. The use of conventional electrical switches to generate the signal in such environments is undesirable given the potentially combustible levels of oxygen that will likely be present near the patient.
As an alternative to conventional electrical switches, the use of a pneumatically actuated switch, which utilizes a pulse of pressurized air to actuate a signal circuit, avoided the safety concerns associated with a conventional switch. Such switches are particularly beneficial where combustion concerns may be present, as in oxygen rich environments, because the construction of the pneumatically actuated switch limits the possibility of arcing which is a problem associated with electrical switching.
U.S. Pat. No. 3,823,285 to Dwyer illustrates an example of a pneumatic actuated bulb device for a patient actuated nurse call system. A deformable pneumatic bulb provides a source of pressurized air to operate an electrical switching circuit that is well suited for use in environments where it is undesirable to use a conventional electrical switch as discussed in the preceding paragraph. A pneumatically actuated switching device comprises an electrically conductive sleeve having a bore. An electrically conductive ball is mounted in the bore and is movable in response to the pneumatic pressure. The other end of the bore is in communication with a tube to which is connected a source of pneumatic pressure, such as the deformable pneumatic bulb. Two conductors are adapted to be connected to two sides of an electrical circuit. The first conductor is in electrical communication with the sleeve and the second conductor is mounted in an opening in the sleeve which extends into the bore. The ball is movable between a circuit open position out of electrical communication with the second conductor, and a circuit closed position in electrical communication with the second conductor and the sleeve. A cam surface extends into the bore and into the path of the ball and cams the ball into electrical communication with the second conductor and the sleeve in the circuit closed position. The sleeve normally is oriented generally vertically, although the device operates satisfactorily when the sleeve is oriented almost horizontally because the ball moves in the bore with very little, if any, friction.
A further development of a pressurizing device is disclosed in U.S. Pat. No. 5,155,309 which embodies a pneumatic bulb having an annular ring configuration with a convexly shaped actuator dome resembling a doughnut to provide a distinctive identification to the bulb for distinction from other pneumatic bulbs that may be utilized for different purposes in a patient area. The construction of the pneumatic bulb includes a base plate to provide support for the bulb and support for a peripheral rim and a center post of the doughnut shaped actuator dome. The base plate includes protruding truncated conical members relied upon to maintain the doughnut shaped actuator at a fixed location on a patient's mattress so that the patient can reliably find the bulb to summon help.
These pneumatically actuated patient call systems comprise an air tube for delivering compressed air for activation of the electrical connection of a jack which is inserted into a receptacle of a wall switch unit of a patient call system. The receptacle can be either recessed into or flushed with a wall plate wherein an air tube positioned at a right angle relative to the electrical connection may be better suited for use with a receptacle that is flushed with the wall plate and wherein an air tube positioned in-line (straight jack) relative to the electrical connection may be better suited for use with a receptacle that is recessed into the wall plate of the wall switching unit.
U.S. Pat. No. 5,736,702 to Roberts, et al. discloses a pneumatically actuated switching device with a housing connection which provides for optional assembly orientations, i.e. an in-line assembly configuration for the switch housing and a right angle configuration for the switch housing relative to a jack for electrical connection with the receptacle of a patient call system. The optional assembly orientations are brought about via a connector which is partially enclosed within a cavity formed in an end of the housing. The cavity of the housing includes opposing side walls and a curved surface located between the side walls. The contour of the curved surface is compatible with the surface of the connector such that the two components can be brought into interfacing contact with one another. In order to maintain the interfacing contact between the connector and the housing, pins extend through the connector and through the opposing side walls of the housing thereby locking the two components together in a preselected angular orientation of the connector relative to the housing. The additional openings in the sidewalls provide for the different angular orientation options for the connector during the assembly of the switch. End connectors form the final closure for maintaining the locked assembly orientation by retaining the pins within the openings in the connector and the housing. The connector and the housing of this multi-position switching device is generally glued together once the pins are in the appropriate openings for forming a desired angular orientation of the connector relative to the housing.
There is a need for a pneumatically actuated switching device for delivering pressurized air for an electrical connection that easily provides an air connector assembly for connection to a housing supporting the electrical connection and which air connector assembly may be selected to provide a desired angle, i.e. an in-line air conduit assembly or a right angle air conduit assembly configuration for the switch housing relative to the electrical connection depending on the type of receptacle in the wall switch unit receiving the electrical connection.
The invention has met this need. An aspect of the present invention provides a pneumatically actuated switching device comprising: a housing having an air chamber; a conductive plunger and a contact spring in the air chamber of the housing; an electrical connection having a first portion extending from the housing and comprising a conductive element for insertion into a receptacle of a patient call system, and a second portion extending into the air chamber of the housing; and an interchangeable air connector assembly connectable to the housing and comprising an air conduit connectable to a pneumatic actuator for generating and discharging a quantity of pressurized air to said pneumatically actuated switching device for operation of the switching device.
The air conduit of the interchangeable air connector assembly is in communication with the air chamber of the housing for receiving the pressurized air from the pneumatic actuator, and which pressurized air is directed into the air chamber of the housing to force the conductive plunger against the electrical connection for completing a circuit for generating a signal in the patient call system. In an embodiment of the invention, the interchangeable air connector assembly has a snap fit connection with the housing and is constructed to selectively position the air conduit at a right angle relative to or in line with the electrical connection. That is, the connector assembly is interchangeable and comprises a first snap fit air connector assembly constructed to position the air conduit at a first angle, for example, at a right angle, with the electrical connection and the conductive element, and a second snap fit air connector assembly constructed to position the air conduit at a second angle, such as, at an 180 degree angle, i.e. in alignment with the electrical connection.
In an embodiment of the invention, the first snap fit air connector assembly and the second snap fit air connector assembly comprise a recessed portion and the air conduit comprises a plurality of fins for securing a pneumatic hose to the air conduit and which hose is press fitted onto the fins of the air conduit and wedged into the recessed portion. In a further embodiment, the air conduit of the air connector assemblies comprise a plurality of barbs for securing the pneumatic hose to the air conduit which hose is press fitted onto the barbs. The contact spring is associated with the conductive plunger and repositions the conductive plunger away from the electrical connection for opening the circuit thereby interrupting the signal in the pneumatic patient call system.
A further aspect of the present invention provides a pneumatic actuator system for a patient call system, comprising: a pneumatic actuator; a pneumatically actuated switching device comprising an electrical connection and an air conduit; and a pneumatic hose connectable to the pneumatic actuator and to the air conduit of the pneumatically actuated switching device for delivering pressurized air to the pneumatically actuated switching device upon operation of the pneumatic actuator for generating an electrical signal when the pneumatic actuator is operated; and an interchangeable air connector assembly for the switching device comprising the air conduit and constructed to selectively position the air conduit at an angle relative to the electrical connection. In an embodiment of the invention, the air connector assembly is interchangeable and comprises a first snap fit air connector assembly constructed to present the air conduit at a first angle, for example, at a right angle relative to the electrical connection and a second snap fit air connector assembly constructed to present the air conduit at a second angle different from the first angle, for example, at a 180 degree angle, i.e. in line with the electrical connection. In an embodiment of the invention, the first snap fit air connector and the second snap fit air connector assemblies comprise a recessed portion and an air conduit comprises a plurality of fins for press fitting and securing a pneumatic hose to the air conduit located in the recessed portion of the air connector assembly. In a further embodiment, the air conduit of the air connector assemblies comprises a plurality of barbs for securing the pneumatic hose to the air conduit. The contact spring is associated with the conductive plunger and repositions the conductive plunger away from the electrical connection for opening the circuit thereby interrupting the signal in the pneumatic patient call system.
A still further aspect of the present invention provides a method for constructing a pneumatic actuator system for a patient call system, the switching device comprising a conductive plunger and a spring, which conductive plunger is forced by pressurized air delivered to the switching device by an air conduit against an electrical connection for completing a circuit, comprising: providing an interchangeable air connector assembly comprising a first snap fit air connector assembly constructed to position an air conduit at a first angle with the electrical connection of the pneumatically actuated switching device, for example, at a right angle relative to the electrical connection and a second snap fit air connector assembly constructed to position an air conduit at a second angle, for example, at an 180 degree angle, i.e. in alignment with the electrical connection of the pneumatically actuated switching device; and selectively inserting the first snap fit air connector assembly and the second snap fit connector assembly into the housing of the pneumatically actuated switching device depending on a desired configuration of the pneumatic actuator system.
It is therefore an object of the present invention to provide a pneumatically actuated switching device having an interchangeable snap fit air connector assembly constructed to selectively position the pneumatically actuated switching device at a predetermined angle for receiving pressurized air for actuating a signal in a patient call system.
It is a further object of the present invention to provide a pneumatically actuated switching device comprising an air connector assembly that is interchangeable, and wherein a first snap fit air connector assembly has an air conduit in communication with the housing of the actuated switching device and at a right angle relative to an electrical connection and a pneumatic actuator producing pressurized air for actuating a signal in a patient call system, and wherein a second snap fit air connector assembly has an air conduit in communication with the housing of the actuated switching device and in line with the electrical connection.
It is still a further object of the present invention to provide an interchangeable air connector assembly that comprises means for securing a pneumatic hose to an air conduit thereof.
These and other objects of the invention will be better appreciated and understood when read in light of the accompanying drawings.
The pneumatically actuated switching device of the invention can be used in a variety of systems and environments in which it is desirable to switch an electrical circuit on or off by remote means. The device is particularly well suited for use with conventional nurse call signal systems and since in this context the features of the invention are highlighted, the invention is described herein in combination with such a system. However, it should be understood that the invention is not limited to such use.
The pneumatically actuated switching devices 10 and 50 are connected to a pneumatic actuator (not shown) via air conduit 12 and 52, respectively, of a patient call system. An example of a pneumatic actuator for a patient call system in which the devices 10 and 50 of the present invention may be connected is disclosed in the aforesaid U.S. Pat. No. 5,736,702. That is, in a similar fashion, pneumatically actuated switching device 10 is connected via air conduit 12 and a pneumatic hose 15 (
With particular reference to
Referring particularly to
Air chamber 20 extends through housing 16 which comprises an inner enlarged diameter portion 26, a middle tapered portion 28, and a reduced diameter end portion 30. Conductive plunger 22 has an enlarged diameter portion 22a and a reduced diameter portion 22b which create a ledge for contact with a spring 24. Contact spring 24 acts to maintain separation, in the absence of a pressure pulse, between the conductive plunger 22 and a portion of the electrical connection components, as will be described in greater detail below.
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Still referring to
As stated hereinabove, contact spring 24 provides for the separation of the plunger 22 and the extension 39 of conductive electrical element 38 in the absence of a pressure pulse. Spring 24 is preferably made from a conductive material so that it also provides for an electrical pathway between plunger 22 and the end of the outer body 34 confronting the air chamber 20. Specifically, contact spring 24 has an end section with a reduced diameter spiral for seating of that portion of the spring between the outer body 34 and insulator 32 to ensure good conductive contact between spring 24 and conductive outer body 34.
The electrical connection of the pneumatically actuated switching device 10 is similar to the pneumatic switch of the aforesaid U.S. Pat. No. 5,736,702 which is incorporated hereby by reference in its entirety. Thus, a temporary electrical connection will result in the following manner. A first electrical pathway will exist between the receptacle and the plunger 22 through the outer body 34 and the contact spring 24. A second pathway will extend from the receptacle to the extension 39 of electrical connection 14 through the jack tip 38. The first and second pathways are kept electrically separated from one another by insulator 32 between the core 37 and the outer body 34 and insulator 33 between jack tip 38 and the outer body 34. Upon the entrance of a pressure pulse into air chamber 20, plunger 22 will slide in air chamber 20 resulting in contact between plunger 22 and the extension 39 of electrical connection 14. This contact will unite the two electrical pathways resulting in an electrical signal, which may be monitored at a central location, such as a nurse's station, indicating that the switch has been activated.
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As shown in
For operation of pneumatically actuated switching device 10, pneumatic hose 15 is connected to a pneumatic actuator and electrical connection 14 is plugged into a receptacle of a pneumatic patient call system. The pneumatic actuator or bulb is pressed and pressurized air is forced through pneumatic hose 15 and into air conduit 12, through air chambers 42 and 40 of connector assembly 18 and into air chamber 20 of housing 16. The pressurized air is forced against conductive plunger 22 to slide conductive plunger 22 thereby causing conductive plunger 22 to contact extension 39 to complete the circuit for generating a signal to the patient call system. Since the pressurized air is delivered momentarily, this signal is only activated momentarily. The pressurized air in assembly 18 and/or in housing 16 is released through the bleed pathway 48. Subsequently, contact spring 24 pushes conductive plunger 22 away from extension 39 for opening of the circuit.
The connector assembly 18 of the device 10 of
With particular reference to
Referring particularly to
Housing 56 comprises an enlarged diameter portion 66, a tapered portion 68, and a reduced diameter portion 70 in which air chamber 60 extends there through. As also shown particularly in
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Contact spring 64 provides for the separation of the plunger 62 and extension 80 of conductive electrical element 54 in the absence of a pressure pulse. Spring 64 is preferably made from a conductive material so that it also provides for an electrical pathway between plunger 62 and the end of the outer body 76 confronting the air chamber 60. Specifically, contact spring 64 has an end section with a reduced diameter spiral for seating of that portion of the spring between the outer body 76 and insulator 74 to ensure good conductive contact between spring 64 and outer body 76.
As described herein above, the electrical connection 54 of the pneumatically actuated switching device 50 is similar to the pneumatic switch of the aforesaid U.S. Pat. No. 5,736,702. A first electrical pathway will exist between the receptacle and the plunger 62 through the outer body 76 and the contact spring 64. A second pathway will extend from the receptacle to the extension 80 of electrical connection 54 through the jack tip 78. The first and second pathways are kept electrically separated from one another by insulator 74 between core 77 and the outer body 76 and insulator 73 between jack tip 78 and outer body 76. Upon the entrance of a pressure pulse into air chamber 60, plunger 62 will slide in air chamber 60 resulting in contact between plunger 62 and extension 80 of electrical connection 54. This contact will unite the two electrical pathways resulting in an electrical signal, which may be monitored at a central location, such as a nurse's station, indicating that the switch has been activated.
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As shown in
The operation of pneumatically actuated switching device 50 is similar to that of switching device 10 as explained herein above.
A method for constructing a pneumatically actuated switching device 10, 50, comprising a housing and an electrical connection, for a pneumatic actuator system for a patient call system such as that shown in
Air connector assemblies 18 and 58 and housings 16 and 56 are made of a suitable nonconductive material, such as plastic and these components may be manufactured by an injection molding process; whereas, conductive plungers 22 and 62 are made of an electrical conductive material, such as metal. Even though a conductive plunger and contact spring are shown to be the housings 16 and 56 of
While the present invention has been described in connection with the embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function of the present invention without deviating there from. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.
