Fail-Proof Control For Hospital Beds
OwnerHans-Peter Bartheltinventor
Life of this patent
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Abstract
A control system for nursing care beds contains additional current and state (switch-on, switch-off) monitoring of the motors to sense potential thermal overload conditions. In an embodiment of the invention, if the control system detects that a motor has remained switched-on longer than a predetermined time and current is also flowing during this time, the control transitions to a blocking state to prevent thermal overloading of the motors.
Claims24
Control (20) for beds that have several parts (12.17), which move with respect to one another, and electric driving motors ((26, 27) for them;
- with an input device (21), via which the user can give control commands to switch on driving motors (26, 27);
- with a process device (22, 23), to which the input device (21) is connected and which has control outputs (33, 34);
- with at least a polarity-reversing switch (24, 25), which has a control input (35, 36) to which the at least one driving motor (26, 27) is connected, and via which the driving motor (26, 27) can be connected, selectively, with a first or a second polarity to a voltage source (43), wherein its control input (35, 36) is connected to the processor device (22, 23) and wherein the motor current can be switched on and off, either via the polarity-reversing switch or a switch lying in series;
- and
- with a monitoring device (22, 42) to monitor the current flow over time through the pertinent driving motor (26, 27), which is connected to the polarity-reversing switch (24, 25);
- wherein the processor device (22, 23) has a program section (FIG. 4) with a timer that starts with the beginning of the current flow for the driving motor (26, 27) and runs during the continual current flow, wherein the timer is reset each time the current flow disappears;
- and
- wherein the process device (22, 23) forcibly brings the polarity-reversing switch (24, 25) or another switch device (62) to the switch-off state if the timer exceeds a prespecified limiting value.
Control for beds that have several parts (12.17), which move with respect to one another, and electric driving motors (26, 27) for them;
- with an input device (21), via which the user can give control commands to switch on driving motors (26, 27);
- with a processor device (22, 23), to which the input device (21) is connected, and which has control outputs (33, 34);
- with at least one polarity-reversing switch (24, 25);
- which has one control input (35, 36);
- which is connected to the at least one driving motor (26, 27);
- and
- via which the driving motor (26, 27) can be connected to a voltage source (43), selectively, currentless or with a first or a second polarity, wherein the control input (35, 36) is connected to the processor device (22, 23);
- and
- with a monitoring device (42, 22) to monitor the current flow over time through the driving motor (26, 27), which is connected to the polarity-reversing switch (24, 25);
- with a safety switch (62),
- which has two stable switching states, wherein it can be switched at least once in a direction from the conducting state to the nonconducting state by a pulse-like current supply
- which lies in series with the at least one polarity-reversing switch (24, 25);
- which is controlled by the monitoring device (22, 23) in such a way that it is controlled from the conducting state to the nonconducting state if the monitoring device (22, 23) determines that current flows in the monitored current path longer than a prespecified time interval.
Control according to claim 21 [sic;
- 20], characterized in that the mechanical safety switch (62) is formed by a bistable relay.
Dependencies are inferred from the claim text.