U.S. patent number 3,829,826 [Application Number 05/282,742] was granted by the patent office on 1974-08-13 for cable fastener for electrocardiograph electrodes.
This patent grant is currently assigned to Hewlett-Packard Company. Invention is credited to Donald M. Brown, Roger E. Dennison.
United States Patent |
3,829,826 |
Brown , et al. |
August 13, 1974 |
CABLE FASTENER FOR ELECTROCARDIOGRAPH ELECTRODES
Abstract
A cable fastener provides an electrically conducting mechanical
connection between a standard male snap fastener commonly used as
an electrocardiograph electrode and a cable. The male snap fastener
is positively held in contact with the cable fastener by a
spring.
Inventors: |
Brown; Donald M. (Bedford,
MA), Dennison; Roger E. (Waltham, MA) |
Assignee: |
Hewlett-Packard Company (Palo
Alto, CA)
|
Family
ID: |
23082925 |
Appl.
No.: |
05/282,742 |
Filed: |
August 22, 1972 |
Current U.S.
Class: |
439/835; 24/667;
600/372 |
Current CPC
Class: |
H01R
11/22 (20130101); A61B 5/274 (20210101); Y10T
24/45801 (20150115) |
Current International
Class: |
A61B
5/0408 (20060101); A61B 5/0416 (20060101); H01R
11/11 (20060101); H01R 11/22 (20060101); H01r
011/22 () |
Field of
Search: |
;24/110,115G,216,218,257
;339/228,252R,252F,252S,252T,255,260-262 ;128/2.1E,2.6E,406,DIG.4
;339/18R,18TP,110,152 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gilliam; Paul R.
Assistant Examiner: Staab; Lawrence J.
Attorney, Agent or Firm: Fox; Stephen P.
Claims
We claim:
1. A cable fastener for coupling a cable to an electrode for
attachment to a patient comprising:
a bracket having a generally planar handle region, a generally
planar coupling region and a generally planar connective
region;
the coupling region including a clearance slot having a first
portion which is wider than a second portion;
the connective region being of predetermined length and having two
ends, connected at one end to the coupling region and at another
end to the handle region, said handle and coupling regions being
essentially parallel and separated by said predetermined length;
and
spring wire means comprising:
a. a base portion connected to the handle region,
b. a coil portion connected to the base portion for providing bias
force,
c. a straight portion connected to the coil portion and situated
entirely between planes defined by the handle region and the
coupling region, the straight portion intersecting and disposed
across said clearance slot in close proximity to the surface of the
coupling region,
d. a partial loop portion connected to the straight portion, the
plane of the loop portion being approximately perpendicular to the
plane of the coupling region, and
e. a terminating portion, one end of which is connected to the
partial loop portion, the other end of which is disposed between
the handle region and the coupling region, and on the opposite side
of the connective region from the clearance slot.
2. A cable fastener as in claim 1 wherein the bracket includes two
bendable tabs for coupling a cable to the cable fastener.
3. A cable fastener as in claim 1 wherein the clearance slot is of
a pyriform shape.
Description
BACKGROUND OF THE INVENTION
In patient monitoring applications, several different types of
cable fasteners have been used to couple electrical impulses from
an electrode on a patient's body to a cable connected to an
electrocardiograph or other monitoring device. Many of these
electrodes, either glued or taped to the patient's body, use a
standard male snap fastener. Traditionally the female portion of
the snap fastener was intended to mechanically couple to the male
portion. The resulting electrical connection, however, is not
noise-free and fatigues easily, causing loose connections.
Additionally, since it is connected by pressing downward on the
patient, a painfully hard push is often necessary to make a good
connection. This type of snap fastener though simple and
inexpensive to produce is difficult to repair.
Some departures have been made from the above described snap. One
example is a hairpin and turn-cam fastener. This type of fastener
makes a good electrical connection when new and allows simple
application without pressing upon sensitive areas of the patient.
The joint between cable and fastener is by a tubular solderless
connector which is crimped on the fastener and the cable, and then
covered with shrink tubing. Unfortunately the fastener is expensive
to make. It offers very little strain relief, and physically
fatigues early in life thereby causing loose connections. The
electrical contact surface is only four pin point surfaces, which
wear away very quickly. The length of the connector provides
leverage which, when lifting the cable, often pries the connector
off the snap. Because shielded wire cables work best when the
exposed metallic fastenings are as small as possible, the length of
this type of fastener is much too great to enhance the benefits of
shielded cable. Also, whenever a patient rolls upon this type of
fastener, he will likely receive a discomforting jab from its end,
or cause the fastener to come off the electrode.
SUMMARY OF THE INVENTION
Accordingly it is an objective of this invention to provide a cable
fastener which engages male snap fasteners of several manufacturers
and slight size variations. The illustrated embodiment of the cable
fastener of this invention includes a metal bracket and a spring
wire joined together. The metal bracket has a clearance hole which
fits over all of the male snaps which are expected to be
encountered and has an offset to allow connections to cup-mounted
snaps. The spring wire provides mechanical retention, and by
holding the bracket in contact with the snap, a durable electrical
connection. A partial loop on the spring wire forms a finger pad
for engaging and disengaging the fastener from the snap.
The cable fastener mates with the male snap of an
electrocardiograph electrode, for example, as it is mounted on a
flat surface or seated in a cup depression. The fastener provides a
good electrical connection throughout its full life and is small to
allow shielding of the cable right up to the skin connection with
the patient. It provides axial strain relief for the wire
connection, and torsional strain relief of the cable jacket from
any molded shell or handle. It is easily applied with one hand
without pressing upon patient, and causes no discomfort when the
patient rolls upon it. When a sharp yank is applied to the cable,
the cable fastener comes off the electrode, rather than the
electrode adhesive parting from the skin. Re-application of the
cable is faster and safer for patient monitoring than
re-application of the electrode. The fastener is able to swivel
about the snap while maintaining good electrical and mechanical
connections. The fastener is also simple and inexpensive to
manufacture.
DESCRIPTION OF THE DRAWING
FIG. 1 is a top view of the preferred embodiment of a cable
fastener for electrocardiograph electrodes.
FIG. 2 is a side view of the preferred embodiment.
FIG. 3 is a perspective view of the preferred embodiment showing a
connection to a male snap.
FIG. 4 is a perspective view of the preferred embodiment showing a
connection to a male snap in a cup shaped depression.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2 there is shown the preferred
embodiment of a cable-to-snap fastener.
The fastener 10 consists of a metal bracket 11 and a spring wire 20
joined together to make one assembly. The metal bracket 11 has a
clearance slot 12 which fits over all of the male snaps expected to
be encountered and has coupling region connected to a connective
region forming a Z-offset 13 to allow connections to cup-mounted
snaps.
Referring to FIG. 1 and the pyriform opening shown, the clearance
slot 12 has two converging sides which fit around the small
diameter of the snap fastener.
Two tabs 14 are provided on the bracket 11 which can be crimped
around the lead to provide axial strain relief. The spring wire 20
provides mechanical retention, and by holding the edge of the
clearance slot 12 against the electrode snap, provides good
electrical connection regardless of cable orientation around snap.
A partial loop 21 on the end of the spring wire form serves as a
finger pad for right index finger operation to engage or disengage
the fastener 10 from the snap. This assembly is intended as both a
unit for field repair, to be covered with only shrink tubing after
crimp and soldering to lead; and as connector to be factory molded
with a plastic handle over the wire-bracket joint. The application
of the entire assembly involves grasping the fastener 10 between
right thumb and right middle finger, while squeezing the spring 20
with the right index finger toward the tabs 14 enough to set the
slot 12 over the snap. The spring 20 is then released to secure the
connection. The fastener is removed in a similar manner. The spring
wire 20 is attached to the bracket 11 on the underside. It passes
above the slot 12 close to the surface of the bracket 11, and is
disposed as a terminating portion beneath the bracket 11 and on the
opposite side of the connective region of the offset 13 from the
clearance slot 12 as shown in FIGS. 1 and 2 so it is protected
against damage.
* * * * *