Blood pressure measuring apparatus

#The invention relates to the field of measuring instruments, and more particularly to a technique and related apparatus for enabling a plurality of blood pressure measurements to be interchangeably performed with various discrete systems, such as within a hospital environment, using a single blood pressure cuff.

#Pressure measuring devices such as sphygmomanometers, that are used to measure the arterial blood pressure of a patent, typically include a pneumatic bulb which inflates a pressure chamber of an attached sleeve that is fitted over a limb (i.e., an arm or a leg) of the patient. A diaphragm or bellows assembly, responsive to changes in fluid pressure of the pneumatic bulb and the sleeve pressure chamber, is positioned in a gage housing which is fluidly connected to the pressure chamber of the sleeve through flexible tubes or hoses. In a mechanical gage housing, a pointer of a dial indicator is interconnected to the bellows assembly through a movement mechanism that is retained within the gage housing, whereby inflation of the bellows causes corresponding circumferential movement of the pointer, enabling a blood pressure measurement procedure to be carried out by a caregiver.

#Typically, the above referred to movement mechanisms are quite intricate and complex, and are akin in terms of their manufacture and precision to Swiss watches. For example, and in one such movement mechanism, a pair of diaphragm springs are attached adjacent opposing ends of a spindle. A bottom end of the spindle is placed in contact with the bellows assembly and a twisted bronze band perpendicularly disposed at the top end of the spindle is connected in parallel by a horizontally disposed spring bent part. As the spindle deflects axially in response to the inflation of the bellows, the bent spring part is also caused to deflect, thereby causing the band to twist. The pointer, attached to the bronze band, therefore is caused to rotate in relation to an adjacent dial face.

#FIG. 1 is a side elevation view, shown in section, of a pressure measuring device according to the present invention;

#FIG. 2 is an enlarged sectional view of the pressure measuring device of FIG. 1, depicting alternate means for attaching a rotatable dial face in relation to the device;

#FIG. 3 is a side elevation view, shown partly in section, of a pressure measuring device having a housing according to a second preferred embodiment;

#The present invention is herein described with reference to several preferred embodiments, each of which specifically relates to blood pressure measuring apparatus. However, it should be evident to one of sufficient skill in the field that certain other variations and modifications could be made utilizing the inventive concepts described herein, as well as alternate applications other than blood pressure measurement, including use in barometers, pressure vessel indicators, pressure sensitive switches, valves, and literally any industrial or medical device requiring a pressure responsive element. Furthermore and throughout the course of the following discussion, terms such as “upwardly,” “downwardly,” “upper,” “lower,” “top,” “bottom,” “vertically,” “horizontally,” and the like are used to provide a frame of reference with regard to the accompanying drawings. These terms, however, should not be treated as limiting with regard to the invention as described herein.

#In addition, a number of terms are used herein which require definitions. “Gearless” as used herein refers to any movement mechanism disposed within a gage housing which does not include a gear or gear-like element. “Hoseless” as used herein refers to a direct connection between a gage housing and an inflatable sleeve of a pressure measuring apparatus without any intermediate hose or hoses therebetween. Several preferred embodiments of hoseless attachments for a blood pressure measuring apparatus are described throughout the course of the following discussion. “Connected” as used herein refers to state of being reversibly (e.g. releasably) or irreversibly joined in direct contact.

#Referring to FIG. 1, there is shown a blood pressure measuring device or apparatus 10 made in accordance with a first embodiment of the invention. The device 10 includes a substantially cylindrical gage housing 12 having an interior cavity 14 defined by a circumferential inner wall 16, an open top end 18, and a bottom end 20. A viewing window or bubble 22, made from glass, plastic, or other suitable transparent material is attached in a known manner to the open top end 18 of the gage housing 12. The bottom end 20 of the gage housing 12 has a diameter which inwardly tapers down to a narrow downwardly extending portion 24 having a bottom opening 26 serving as an inlet port for admitting a fluid. Preferably, the diameter of the narrow extending portion 24 is about one third of the diameter of the major portion of the housing 12, though it will be apparent from the following discussion that this parameter can be suitably varied depending upon the application.