Patient ambulation motion detector with multiple switch motion detection

• US 5,146,206 A
• Filed: 04/12/1991
• Issued: 09/08/1992
• Est. Priority Date: 11/07/1989
• Status: Expired due to Fees

• Current Assignee: Callaway, James J.
• Original Assignee: Callaway, James J.
• Inventors: Callaway, James J.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Oda, Christine K.
• Application Number:
  US07/683,958
• Time in Patent Office: 515 Days
• Field of Search: 340/573, 340/689, 340/686, 340/575, 340/568, 200/188, 200/220, 200/221, 200/61.52, 200/61.45 R, 200/DIG. 2, 128/782
• US Class Current: 340/573.7
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 2562/166 the sensor is mounted on a specially adapted printed circuit board
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/6828 Leg
• CPC Class Codes: G08B 21/22 responsive to presence or absence of persons
• CPC Class Codes: Y10S 200/02 Body attached switches

Abstract

A patient ambulation motion detector intended for attachment to a patient'"'"'s body. The detector includes a motion sensor switch and a detachment detector switch which are mounted on a circuit board, the circuit board being in turn enclosed within an attachment casing which is attachable to a lateral surface of the patient'"'"'s body. The motion sensor comprises three SPST mercury switches mounted to the circuit board and oriented so as to be responsive to declination of that portion of the patient'"'"'s body to which the detector is attached and which declination is indicative of impending ambulation, but non-responsive to positions in which the posture of the patient is not indicative of impending ambulation. The detachment detector switch is a spring contact switch which is openable and closable by a plunger acting thereon and sensitive to detachment of the detector from the patient'"'"'s body. The detector may be wired to a conventional switched nurse call system. When multiple mercury switches are employed, the switches are connected in series so as to prevent false alarms.

Claims

1. A motion detector to be attached to a portion of a patient'"'"'s body so as to signal impending ambulation of the patient, the motion detector comprising:

motion sensor circuit means including at least first, second and third switch means;

each switch means comprising portions defining an elongated chamber having first and second spaced ends and a longitudinal axis extending therebetween, a mercury ball contained within said chamber for gravitational movement between said first and second ends, and spaced electrical contacts disposed at said first end of said chamber, each switch means being closed when said first end of said chamber is below said second end such that said mercury ball conductively connects said contacts, and otherwise being open;

said first, second and third switch means being electrically connected in series whereby said motion sensor circuit means is completed to provide a signal of impending ambulation only when all of said first, second and third switch means are closed;

support means defining a first reference plane, and having a proximal end and a distal end, a first reference line on said first reference plane extending between said proximal and distal ends, and side portions laterally spaced from said first reference line;

attachment means for securing the motion detector to a portion of a patient'"'"'s body with said proximal end of said support means proximal the patient'"'"'s head relative to said distal end;

said first, second and third switch means being carried by said support means in a fixed three-dimensional configuration with respect to each other and with respect to said first reference plane;

said first switch means being fixedly carried by said support means with its longitudinal axis aligned with said first reference line and inclined with respect to said first reference plane, said second end of said first switch means being lower than said first end when said motion detector is in a first position wherein said first reference plane is generally horizontal, whereby said first switch means is open in said first position, and closed only when the motion detector is pivoted about said distal end of said support means from said generally horizontal first position to a second position wherein said proximal end of said support means is raised above said distal end past a predetermined threshold indicative of impending ambulation of the patient;

said second and third switch means being fixedly carried by said support means on opposite sides of said first reference line with their longitudinal axes inclined toward said first reference line, each of said second and third switch means having its first end lower than its second end when the motion detector is in said second position, one or the other of said second and third switch means having its second end lower than its first end when the motion detector is rotated about said first reference line to raise one side of said support means substantially above the other.

2. The motion detector of claim 1, and further comprising:

an insulated cord containing two electrical conductors connected to said support means in parallel with the series connected first, second and third switch means; and

a plug member attached at one end of said insulated cord for connecting the motion detector to a patient monitoring system.

3. The motion detector of claim 1, wherein each of said second and third switch means have its first end lower than its second end when the motion detector is in both said first and second positions.

4. The motion detector of claim 1, and further comprising housing means for housing said motion sensor circuit means and said support means, said attachment means being connected to a surface of said housing means.

5. The motion detector of claim 1, wherein said support means includes a substantially rigid support member having an upper and lower surface, said lower surface being juxtaposed to the portion of the patient'"'"'s body in use, said first, second and third switch means being fixedly secured to the upper surface of said support member in said fixed three-dimensional configuration.

6. The motion detector of claim 5, wherein said first switch means is carried by said support member with its longitudinal axis inclined at approximately 100°

relative the upper surface of the support member and the proximal end thereof.

7. The motion detector of claim 5, wherein said second and third switch means are carried by said support member with their longitudinal axes inclined at an angle of approximately 30°

relative to the upper surface of the support member.

8. The motion detector of claim 7, wherein the axes of said second and third switch means are offset at an angle of approximately 15°

with respect to a second reference line which extends substantially perpendicularly with respect to said first reference line on said first reference plane.