Transducers with quick dome connect systems

Methods and apparatus for interconnecting a transducer body with a fluid-receiving transducer dome provide the transducer body with a radial shoulder, where an annular tightening member, rotatable relative to the transducer body, is also provided. An axial bias between the tightening member and the radial shoulder resiliently restrains the tightening member and the transducer body against movement away from each other. A groove for receiving a fastening member projecting either from the tightening member or the dome is provided at the dome or the tightening member. This groove is delimited with a stepped rigid tongue for retaining the fastening member therein. The dome and the transducer body are biased into fluid-tight engagement with the axial bias acting between the radial shoulder and the annular tightening member and acting on the dome through the projecting fastening member and rigid tongue.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The subject invention relates to pressure and other transducers, to 
transducer dome constructions, and to transducer dome quick 
connect/disconnect systems. 
2. Disclosure Statement 
The following disclosure statement is made pursuant to the duty of 
disclosure imposed by law and formulated in 37 CFR 1.56(a). No 
representation is hereby made that information thus disclosed in fact 
constitutes prior art, inasmuch as 37 CFR 1.56(a) relies on a materiality 
concept which depends on uncertain and inevitably subjective elements of 
substantial likelihood and reasonableness and inasmuch as a growing 
attitude appears to require citation of material which might lead to a 
discovery of pertinent material though not necessarily being of itself 
pertinent. Also, the following comments contain conclusions and 
observations which have only been drawn or become apparent after 
conception of the subject invention or which contrast the subject 
invention or its merits against the background of developments which may 
be subsequent in time or priority. 
U.S. Pat. No. 3,587,322, by S. L. Lobdell et al, issued June 28, 1971, 
discloses a pressure transducer mounting having an adapter that may act as 
a fluid-receiving transducer dome. According to that patent, such dome has 
an internal thread for engaging an external thread on the transducer 
mounting body. With such an arrangement, one or more lines would be 
subjected to turning torque, when the transducer dome is threaded onto the 
transducer mounting body, or is removed therefrom, while one or more fluid 
lines are connected to the transducer dome and an electrical line or cable 
is connected to the transducer mounting body. The same comments would 
appear to be applicable to the threaded transducer dome design of U.S. 
Pat. No. 4,252,126, by J. P. Mandl, issued Feb. 24, 1981. 
Threaded domes are also apparent from U.S. Pat. No. 3,499,434, by G. 
Ullrich et al, issued Mar. 10, 1970 and disclosing a sound and pressure 
diagnostic apparatus having several lines connected thereto, and U.S. Pat. 
No. 4,072,056, by A. St. Jacques Lee, issued Feb. 7, 1978, for a fluid 
containment structure for transducer systems. 
In general, such systems tended to impose turning torques on attached fluid 
lines and electrical cables, failed to provide a constant and uniform 
sealing pressure on the transducer diaphragm, were prone to 
over-tightening, and did not enable any quick connect and disconnect 
operation of the dome relative to the transducer body. 
U.S. Pat. No. 4,185,641, by T. G. Minior et al, issued Jan. 29, 1980, 
discloses a spring loading system, with resilient tongues that engage 
corresponding projections in such a manner as to draw the dome and 
transducer together when one is rotated with respect to the other. 
Detent notches for the projection are said to insure that the force between 
the dome and the transducer is always the same. Reference may in this 
respect also be had to the related article by J. F. Dias et al, entitled 
Capacitive Blood Pressure Transducer, ISA Transactions, Vol. 19, No. 3, 
pp. 19 to 23. 
For a disclosure of twist-lock containers, reference may be had to U.S. 
Pat. No. 4,279,355, by E. L. Schwartz et al, issued July 21, 1981. With 
such twist-lock containers, as well as with the pressure dome connecting 
system disclosed as mentioned above by Minior et al and Dias et al, it is, 
of course, still necessary to twist the dome and transducer body relative 
to each other during attachment and detachment which, depending on the 
application, may in practice shift the fluid and electrical lines. 
A few years ago, a cordless vibrating massager was developed with a 
removable cap for the battery casing at the rear thereof, as may be seen 
from the U.S. Pat. No. Des. 210,922, issued Apr. 30, 1968, and U.S. Pat. 
Nos. 3,451,391, issued June 24, 1969, and 3,549,920, issued Dec. 22, 1970, 
and all naming J. H. Tavel as inventor. As apparent from the latter 
patents, the inside of the sidewall of the end cap was provided with a 
pair of diametrically spaced bosses which protrude inwardly a short 
distance. The outside of the lower end of the battery housing was provided 
with a pair of substantially L-shaped slots, which have a short axial leg 
connecting with a substantially longer transverse leg. 
The bosses were dimensioned and adapted to slidably move into the open 
lower end of the short axial legs of the slots and then moved from the 
upper end of the axial leg into the transverse leg. The lower edge of each 
of the transverse legs of the slots was angled slightly downwardly from 
its closed end towards its junction with the axial leg. A short stop was 
disposed at one end of the lower edge of each of the transverse legs, 
directly adjacent to the intersection of the transverse leg with the axial 
leg. The stop acted to engage the boss in its counterclockwise movement 
along the axial leg. The boss could be moved past the stop only by moving 
the end cap inwardly against the pressure of the contact spring of a 
battery terminal. The stop accordingly was supposed to prevent accidental 
removal of the end cap and batteries and to permit such removal only when 
the end cap was moved inwardly and then rotated past the stop. In cordless 
electric vibrators actually built and marketed under these patents, the 
lower edge of each of the transverse legs of the transverse slots has no 
longer been angled downwardly, but rather extends in a plane perpendicular 
to a longitudinal axis of the elongate battery housing or vibrator. 
As another example of an area which had to deal with the task of providing 
quick connect and disconnect of interrelated parts, the connector field 
may be referred to. For instance, U.S. Pat. No. 3,646,495, by R. R. 
Cowmeadow, issued Feb. 29, 1972, shows a connector device having a detent 
lock with a leaf detent spring disposed between facing annular surfaces of 
a pair of rings and engageable in a key slot in one of the rings to lock 
them against relative rotation. 
Another example is seen from U.S. Pat. No. 3,888,559, by R. L. Geib, issued 
June 10, 1975, and showing a quick disconnect connector assembly including 
a plurality of ball bearing locking members in the plug portion of the 
connector, cooperating with a groove in a corresponding receptacle portion 
for locking these two components together. The position of the ball 
bearing locking members was controlled by a spring biased locking spring. 
Pulling the locking ring against the force of its biasing spring released 
the ball bearing locking members for quick separation of the two connector 
portions. 
Another quick connect coupling is apparent from U.S. Pat. No. 3,901,538, by 
S. W. Blakely, issued Aug. 26, 1975, and disclosing a threaded male 
coupling member in which a female coupling member is provided of such 
design that the male member may be inserted and locked without moving or 
rotating the female member. An inwardly sprung, resilient snap spring is 
situated within a tubular shell member and is provided with internal 
threads for engaging and blocking the male member in position. The shell 
is contoured to hold the snap spring in locking engagement with the male 
member in the event that force is applied to the coupling to pull it 
apart. 
Another connector, manufactured by the Cannon Division of ITT under the 
desigantion 7841 MS 3122E 14-5P for the female member and 7729, MS 
3116F14-5S for the male member, has three circumferentially distributed 
pins projecting from a cylindrical outer wall of the female member and 
engaging three slanted slots in an annular tightening member encompassing 
and being retained at the male member and being rotatable relative 
thereto. 
At the end of each of these slanted slots, there is a radial bore for 
receiving one of the projecting pins of the female member; the arrangement 
being such that the projecting pins of the female member click into the 
corresponding radial bores of the tightening member at the end of a 
rotation thereof. 
Reference may also be had to quick connect pipe couplings and fittings. For 
instance, U.S. Pat. No. 3,924,881, by J. V. O'Connor, issued Dec. 9, 1975, 
shows a pipe fitting in which a female member includes shoulder portions 
cooperating with corresponding elements of an annular gasket retaining 
element. 
Despite this wealth of proposals and designs, the need for an improved 
transducer body and dome interconnecting system has persisted. 
SUMMARY OF THE INVENTION 
It is a general object of this invention to overcome the disadvantages and 
meet the needs expressed and implicit in the above disclosure statement 
and in other parts hereof; 
It is a germane object of this invention to provide an improved system for 
interconnecting a transducer body with a transducer dome. 
It is a related object of this invention to provide for constant and 
uniform sealing pressure on a transducer diaphragm or between a transducer 
dome and transducer body. 
It is also a related object of this invention to provide a transducer body 
and dome interconnection that cannot be overtightened. 
It is also a related object of this invention to avoid imposition of a 
turning torque on fluid lines, electrical leads and parts of a transducer 
body and dome assembly, when these parts are connected and disconnected. 
It is a germane object of this invention to provide improved quick connect 
and disconnect coupling systems for selectively attachable and removable 
transducer domes. 
Other objects of the invention will become apparent in the further course 
of this disclosure. 
From a first aspect thereof, the subject invention resides in methods and 
apparatus for interconnecting a transducer body with a fluid-receiving 
transducer dome, comprising, in combination, the steps of, or means for, 
providing the transducer body with a radial shoulder, providing around the 
transducer body at the radial shoulder an annular tightening member, 
rendering the tightening member rotatable relative to the transducer body, 
providing between the tightening member and the radial shoulder an axial 
bias resiliently restraining the tightening member and the transducer body 
against movement away from each other, providing in one of the tightening 
member and the dome a groove for receiving a fastening member projecting 
from the other of the tightening member and the dome, delimiting the 
groove with a stepped rigid tongue for retaining the fastening member in 
the groove, and biasing the dome and the transducer body into fluid-tight 
engagement with the axial bias acting between the radial shoulder and the 
annular tightening member and acting on the dome through the projecting 
fastening member and rigid tongue. 
From another aspect thereof, the subject invention resides in methods and 
apparatus for interconnecting a transducer body, having a longitudinal 
axis, with a fluid-receiving transducer dome, and, more specifically, 
resides in the improvement for enabling the transducer body and the dome 
to move angularly relative to each other, together with any lines attached 
thereto, while preserving an interconnection of the body and dome intact, 
comprising in combination, the steps of, or means for, providing the 
transducer body with a radial shoulder, providing around the transducer 
body at the radial shoulder an annular tightening member, rendering the 
tightening member rotatable relative to the transducer body, providing 
between the tightening member and the radial shoulder an axial bias 
resiliently restraining the tightening member and the transducer body 
against movement away from each other, providing in one of the tightening 
member and the dome a groove for receiving a fastening member projecting 
from the other of the tightening member and the dome, delimiting the 
groove with a rigid tongue having first and second shoulders for retaining 
the fastening member in the groove therebetween, providing the rigid 
tongue with a land extending between the shoulders and lying in a plane 
extending at right angles to the longitudinal axis, providing the 
fastening member with a predetermined width parallel to said plane, 
rendering the fluid-receiving dome and the transducer body angularly 
movable with respect to each other while the fastening member is retained 
in the tongue, by making the land along said plane at least twice as long 
between the shoulders as the predetermined width of the fastening member, 
and biasing the dome and the transducer body into fluid-tight engagement 
with the axial bias acting between the radial shoulder and the annular 
tightening member and acting on the dome through the projecting fastening 
member, the land and the rigid tongue. 
Other aspects of the invention will become apparent in the further course 
of this disclosure, and no limitation whatever is intended by this summary 
of the invention in any respect.

DESCRIPTION OF PREFERRED EMBODIMENTS 
The fluid pressure transducer 10 shown in the drawings has a transducer 
body 12 and a removable dome 13 associated therewith. By way of example, 
the dome 13 may be of a transparent plastic or other conventional 
transparent material. The transducer body 12 houses a pressure transducer 
in an upper portion 14 and such pressure transducer presents a diaphragm 
15 to the fluid chamber 16 of the dome 13. If desired, the transducer or 
diaphragm 15 may be separated from the dome chamber 16 by a disposable or 
other membrane (not shown) in accordance with conventional practice. 
The dome 13 has a first tube 18 and a second tube 19. By way of example, 
the tube 18 may be connected to a source of fluid via a symbolically 
illustrated fluid line 21, and the tube 19 may be connected to a source of 
fluid pressure variations or pulses via a symbolically illustrated second 
fluid line 22. By way of example, the line 22 may be part of a 
conventional catheter connectable to the circulatory system of a living 
organism, while the line 21 may be connected to a source of a compatible 
solution as, for instance, conventional in blood pressure monitoring and 
other hemodynamic pressure sensing systems. The usual Linden, Luer or 
other fittings may be employed for releasably attaching the fluid lines 21 
and 22 to the dome inlets and outlets 18 and 19. Conventional shutoff 
valves (not shown) may also be provided in or at the fluid lines 21 and 
22. 
The transducer in the body 12 or part 14 is connected by an electric cable 
25 to electric measuring, monitoring and other typically conventional 
circuitry or apparatus (not shown) for measuring, monitoring or evaluating 
the fluid variations, fluctuations or pulses sensed by the transducer via 
diaphragm 15 at the dome chamber 16. 
An electrical connector 26, having, for instance, a male plug 27 on an end 
of the cable 25 and a female receptacle 28 integral with the transducer 
body 12, may be employed for conducting electrical currents to and from 
the pressure transducer. A circular nut or threaded annulus 29 may be 
employed for releasably securing the plug 27 to the receptacle 28. 
While there is no objection to such a threaded interconnection 31 at the 
electric cable 25, similar threaded connections between the transducer 
body 12 and dome 13 are proving increasingly disadvantageous and 
inconvenient in practice. 
Disadvantages and inconveniences encountered with threaded dome and 
transducer body interconnections include lack of a constant and uniform 
sealing pressure at the transducer diaphragm 15, danger of and detriment 
from overtightening of the threaded interconnection, imposition of a 
turning torque on at least the dome and the fluid lines connected thereto 
during tightening and release of the threaded interconnection, and the 
slowness imposed by threaded interconnection in the dome attachment and 
removal process. 
These disadvantages and detriments are overcome by the systems and methods 
for interconnecting a transducer body with a fluid-receiving transducer 
dome, a preferred embodiment of which is shown at 33 in the accompanying 
drawings. 
In this respect, the transducer body 12 has or is provided with a radial 
shoulder 34 which, in the illustrated preferred embodiment, extends 
circumferentially about the transducer body. An annular tightening member 
or annulus 36 is provided around the transducer body 12 at the radial or 
circumferential shoulder 34. This tightening member 36 is or is rendered 
rotatable relative to the transducer body 12. An axial bias 37 is provided 
between the tightening member and the radial shoulder 34 for restraining 
such tightening member 36 and the transducer body 12 against axial 
movement away from each other. 
A spring 38, such as a Belleville or other annular spring, may be provided 
between the annular tightening member 36 and the radial shoulder 34 to 
provide the axial bias 37. 
According to the illustrated preferred embodiment, the annular tightening 
member 36 is provided with the spring 38 as a bias spring extension 
engaging the radial shoulder 34 to provide the axial bias 37. This spring 
extension may be annular, like the circumferential shoulder 34. The 
annular spring extension 38 of the tightening member 36 thus preferably 
engages the circumferentially provided shoulder 34 circumferentially to 
provide the axial bias 37. 
The annular spring 38 may be embedded or attached to the tightening member 
36 as a resilient extension thereof or, alternatively, may be formed in 
one piece with the annular tightening member as desired. 
A groove 41 is provided in or at a side of the dome 13 for receiving a 
fastening member 42. In principle, the groove 41 could be provided in the 
annular tightening member 36, while the fastening member 42 would then 
project from the side of the dome 13. However, in the illustrated 
preferred embodiment of the invention, the annular groove 41 is provided 
in the dome 13, while the fastening member 42 projects inwardly from the 
tightening member 36. In more general terms, one of the tightening member 
36 and the dome 13 is provided with a groove 41 for receiving the 
fastening member 42 projecting from the other of the tightening member 36 
and dome 13. 
In either case, the groove 41 is delimited by or with a stepped tongue 43 
for releasably retaining the fastening member 42 in the groove 41. 
Unlike, for instance, the tongues in the pressure dome of the above 
mentioned U.S. Pat. No. 4,185,641, the tongue 43 is rigid to provide a 
most precise and stable locking or abutment surface for the fastening 
member 42, and to avoid any possibility of any operator jamming the 
fastening member into a side of any flexible or resilient tongue. 
Also, rather than biasing the dome onto the transducer body with any 
resilient tongue, the illustrated preferred embodiment of the subject 
invention biases the dome 13 and the transducer body 12 into fluid-tight 
engagement with the axial bias 37 or annular spring extension 38 acting 
between the radial shoulder 34 and the annular tightening member 36 and 
acting on the dome 13 through the projecting fastening member 42 and rigid 
tongue 43, either in that order, as shown in the drawings or in a reverse 
order, if the groove 41 and tongue 43 are provided in the annular 
tightening member 36, while the fastening member 42 projects from a side 
of the dome 13. 
An annular or circular gasket 45 may be provided in and project from a 
corresponding slot 46 in the dome 13, so as to enhance the fluid-tight 
engagement of the dome with the transducer body at the diaphragm 15 and 
fluid chamber 16. 
According to an embodiment of the invention, a further groove 141 is 
provided in one of the tightening member 36 and the dome 13 for receiving 
a further fastening member 142 projecting from the other of that 
tightening member 36 and dome 13. The further groove 141 is delimited by 
or with a stepped rigid further tongue 143 for releasably retaining the 
further fastening member 142 in such further groove. The transducer dome 
13 and transducer body 12 are biased into fluid-tight engagement with the 
axial bias 37 also via the further fastening member 142 and further tongue 
143. 
In terms of the illustrated embodiment of the subject invention, the 
transducer dome 13 is provided with a pair of lateral grooves 41 and 141 
for receiving a pair of fastening members 42 and 142, respectively, 
projecting inwardly from diametrically opposed regions of the annular 
tightening member 36. 
The grooves 41 and 141 are delimited with stepped rigid tongues 43 and 143, 
respectively, for retaining the fastening members 42 and 142 in the 
grooves 41 and 141. 
As best seen from the bottom view of FIG. 3 of the dome 13, that 
illustrated dome also has diametrically opposed axial lateral slots 48 and 
148 for receiving the fastening members 42 and 142 projecting inwardly 
from the tightening annulus 36. The axial slots or grooves 48 and 148 
communicate, respectively, with the radial or peripheral grooves 41 and 
141, so that the tightening projections 42 and 142, after insertion 
through the slots 48 and 148, may readily be positioned past shoulders 49 
and 149 into the grooves 41 and 141 for engagement by the tongues 43 and 
143 under the power of the axial bias 37, upon angular movement of the 
tightening annulus 36. 
A slanted portion 51 at the axial slot 48 ahead of the shoulder 49 
facilitates insertion of the fastening member 42 into the groove 41. A 
similar slanted portion is provided at the beginning of the second tongue 
143, though being covered from view in the drawings. 
The rigid tongue 43 is provided with first and second shoulders 49 and 52 
for retaining the fastening member 42 in the groove 41. The rigid tongue 
43 is also provided with a flat edge or land 54 extending between the 
shoulders 49 and 52 and lying in a plane extending at right angles or 
perpendicular to a longitudinal axis 56 of or through the dome 13 or 
transducer body 12. This land 54 receives the fastening member 42 under 
the influence of the axial bias 37. 
In the illustrated embodiment of the invention, the further or second rigid 
tongue 143 is also provided with first and second shoulders 149 and 152 
for retaining the fastening member 142 in the groove 141. The rigid tongue 
143 is provided with a second land 154 extending between the shoulders 149 
and 152 and lying also in the plane extending perpendicularly to the 
longitudinal axis 56 for receiving the second fastening member 142. 
The flat perpendicular lands 54 and 154 assure a constant and uniform 
sealing pressure at the transducer diaphragm 15. 
Where the fastening member 42 is provided with a predetermined width 58 
parallel to the plane of the land 54, the fluid-receiving dome 13 and the 
transducer body 12 are rendered angularly movable with respect to each 
other while the fastening member 42 is retained at the tongue 43, by 
making the land 54 along the mentioned plane at least twice as long 
between the shoulders 49 and 52 as the predetermined width 58 of the 
fastening member. In other words, the distance 59 between the shoulders 49 
and 52 is at least twice the width 58 of the fastening member 42. The 
second fastening member 142 and tongue 154 may be provided with 
corresponding dimensions. 
By way of background, it may be seen from the pressure dome arrangement 
disclosed in the above mentioned U.S. Pat. No. 4,185,641 that relative 
movement of the fluid lines and electrical cable in that arrangement may 
result in an unintended release of the dome from the transducer body. 
In the illustrated preferred embodiment of the invention, this is avoided 
by making the lands 54 and 154 flat for a distance longer than the width 
of each of the fastening members or tabs 42 and 142. Accordingly, a 
principle which has been employed in the above mentioned cordless 
vibrating massager to provide an on/off electrical switch action at a 
battery casing cap, has through the illustrated preferred embodiment of 
the subject invention become a means or system for permitting angular 
movement between fluid dome and transducer body and the respective lines 
and conduits connected thereto, without in any manner impairing or 
affecting the fluid-tight seal necessary for perfect operation of the 
pressure transducer. Accordingly, in the case of a blood pressure sensing 
or monitoring transducer, the illustrated preferred embodiment of the 
invention provides for a considerable tolerance in patient and equipment 
movement without impairment of the monitoring or sensing function. The 
same applies, of course, to other areas of utility of the pressure 
transducer 10 where movement of attached lines is to be tolerated and is 
not to have any adverse effect on high-precision pressure and other 
measurements. 
The subject extensive disclosure will render apparent or suggest to those 
skilled in the art various modifications and variations within the spirit 
and scope of the subject invention and equivalents thereof.