US 20060272097 A1
A vibrating patient support apparatus has a resonant referencing percussion device preferably located internally to a cover of a mattress of the apparatus. The percussion device delivers a percussion or vibration at a controlled operating frequency that is preferably slightly less than a resonant frequency located internal to the mattress of the apparatus. With the various weight distributions of a patient, the device is capable of determining the ever shifting resonant frequency via control signals received by a controller from a pressure sensor or accelerometer of the device. Because the operating frequency is slightly less than the natural resonating frequency, energy of the system is conserved. Because the operating frequency is not the controller calculated resonant frequency, wear on the device and potential damage is minimized.
1. A patient support apparatus for providing therapeutic treatment to a patient, the patient support apparatus comprising:
a loaded state wherein at least a portion of the patient is supported by the patient support apparatus;
an unloaded state wherein the patient is not being supported by the patient support apparatus;
a percussion device for producing a variable oscillating displacement at an operating frequency;
a resonating pad having at least one natural resonant frequency when in the unloaded state and at least one shifted resonant frequency when in the loaded state and wherein each one of the at least one shifted resonant frequency corresponds to a respective one of the natural resonant frequency;
a controller for electrically operating the percussion device; and
a sensor for communicating a control signal that corresponds to an amplitude of vibration processed by the controller.
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12. A patient support apparatus for providing therapeutic treatment to a patient, the patient support apparatus comprising:
a cushioning member;
a percussion device having a plurality of bladders located below the cushioning member and a sensor;
a variable speed pump for flowing a pressurized medium into the plurality of bladders;
a valve system for controlling flow to and from the bladders for inflation and deflation at a controlled operating frequency;
a controller for controlling the valve system and the variable speed pump based in-part on a signal received from the sensor.
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the flow medium of the pump being pressurized air; and
the cushioning member being a main bladder of a firmness setting device that receives controlled pressurized air from the pump.
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This application claims the benefit of U.S. provisional patent application Ser. No. 60/677,728, filed May 4, 2005, the advantages and disclosure of this application is hereby incorporated by reference.
The present invention relates generally to a patient support apparatus and more particularly to a resonant frequency referencing percussion device of a vibrating patient support apparatus.
Patient support systems are well known in the art for providing therapy to a patient. A typical patient support apparatus comprises a mattress having a plurality of air bladders for supporting the patient against the bias of gravitational forces, a percussion device that alternates inflation and deflation of air bladders to provide percussion and vibration therapy to the patient, and a rotation device, usually positioned beneath the mattress, to rotate the patient from side to side. Percussion, vibration, and rotation therapy assist in reducing pulmonary problems and bed sores, respectively.
One example of a rotation device in a mattress is shown in U.S. Pat. No. 5,611,096 to Bartlett et al. and incorporated herein by reference in its entirety. The rotation device of Bartlett et al. has two selectively inflatable and deflatable air bladders lying longitudinally beneath the mattress to provide rotation therapy to the patient for reducing bed sores. A controller including an operator input panel and display is used to control the rotation device. The input panel includes a plurality of raised buttons for advancing through and adjusting parameters associated with rotation functions.
An example of a percussion or vibrating device in a mattress is shown in U.S. Patent Application Publication No. 2004/0193078 A1, to Flick et al. and incorporated herein by reference in its entirety. The percussion device of Flick et al. discloses a vibrating pad having a plurality of bladders that fill and deflate with the flow of air or fluid at a prescribed frequency controlled by a controller causing the above mattress or mattress cushion to vibrate. This vibration therapy is capable of reducing pulmonary problems such as the accumulation of secretions in the lungs.
Unfortunately, controllers of known percussion devices do not sense or process displacement amplitude with displacement frequency of the vibrating media of the bladders. Hence, known percussion devices are not capable of detecting and/or utilizing natural resonant frequencies of the vibrating media. If the operating vibration frequency of known percussion devices is too distant from the natural resonant frequency, energy is wasted. If the operating vibration frequency is unintentionally at the natural resonant frequency, then damage or accelerated wear of the patient support apparatus may occur.
A vibrating patient support apparatus has a resonant referencing percussion device preferably located internally to a cover of a mattress of the apparatus. The percussion device delivers a percussion or vibration at a controlled operating frequency that is preferably slightly less than a resonant frequency located internal to the mattress of the apparatus. With the various weight distributions of a patient, the device is capable of determining the ever shifting resonant frequency via signals received by the controller from a pressure sensor or accelerometer of the device. Because the operating frequency is slightly less than the natural resonating frequency, energy of the system is conserved. Because the operating frequency is not the controller calculated resonant frequency, wear on the device and potential damage is minimized.
Preferably, the patient support apparatus includes a number of other devices for patient comfort and therapeutic treatment substantially located in a manageable and light weight mattress. All the devices are generally light weight with moving parts generally being bladders, thus relatively quiet when operating. For ease of manufacturing and cost, a substantial portion or all of the devices operate off of a common pump for preferably flowing pressurized air to an assortment of bladders. For instance, the percussion device preferably has bladders. Moreover, the apparatus preferably has a bladder operated rotation device for rotating a patient to minimize bed sores, a bladder operated firmness setting device for providing patient comfort, and an air loss control system for flowing air through the mattress to control temperature.
Objects, features and advantages of the present invention include a patient support apparatus that has a relatively lightweight and manageable mattress having numerous devices for therapeutic treatment. Other advantages of the apparatus include a relatively simple and robust design that is inexpensive to manufacture, reduces wear and warranty costs and reduces energy consumption.
Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a vibrating patient support apparatus of the present invention is generally shown at 10.
Still referring to
Preferably, a pendant 28 of the controller 72 is supported by a tower 30 coupled electrically to the mattress 20 and preferably supported structurally by the bed frame 12. The pendant 28 includes user interface 32 of the patient support apparatus 10 used to operate at least a portion of the functions of the mattress 20. The user interface 32 is preferably of a touch-screen display type that is well known to those skilled in the art for operator input, as well as output, based upon the particular software used to configure the user interface or touch-screen display 32. Here, the touch-screen display 32 has input and output capabilities. These features are shown in application Ser. No. 11/260,452, filed Oct. 27, 2005, hereby incorporated by reference.
The percussion-vibration mechanism 38 of the percussion device 86 is positioned below the main air bladder 36, hereinafter referred to as the percussion mechanism 38. The percussion mechanism 38 provides both percussion and vibration therapy to the patient. The particular therapy being employed is dependent on the frequency or the number of beats per second generated by the percussion mechanism 38. For example, and not to be limited to these examples, the percussion therapy usually employs 1-7 beats per second (i.e. 1-7 hertz) and the vibration therapy employs 7 to 25 beats per second (i.e. 7-25 hertz). The percussion mechanism 38 may employ mechanical fingers or rollers to impart the percussion motion, but preferably comprises a pair of inflatable percussion bladders 39, best shown in
Preferably, a rotation mechanism 40 of the rotation device 88 for rotation therapy is positioned below the percussion mechanism 38. The rotation mechanism 40 provides rotation therapy to the patient by rotating the patient from side to side. Along with percussion and percussion-vibration therapy, rotation therapy assists in reducing bed sores and pulmonary problems of the patient. The rotation mechanism 40 is preferably a pair of longitudinally positioned rotation bladders 42, shown in
Referring specifically to
The second control unit 54 of the main control system 70 in the form of a rigid box is shown beneath the cover 24 of the mattress 20 within the perimeter of the frame 34 (see
With further regards to the percussion device 86 and more specific to the present invention,
In operation, and assuming no patient load is placed upon the resonating pad 100 of mechanism 38, (see
For ease of explanation, each bladder 39 has a pressure transducer 102, thus each bladder 39 can react to weight changes of the respective overhead portion of the patient. However, one skilled in the art would now know that a plurality of bladders 39 could be controlled by one pressure transducer 102. If, for instance possibly due to manufacturing cost, only one pressure transducer 102 is utilized, its optimal location would be toward the center of the mattress 22 or under the lungs of the patient since percussion therapy is primarily used for treatment of the lungs.
In operation of the percussion device 86 with the weight of a patient on the mattress 22, the variable speed air pump 50 operates through the percussion control system 60 that preferably includes a double diaphragm valve system 99 for controlled inflation and deflation of the percussion bladders 39. The inflation of the percussion bladders 39 by the pump 50 is oscillated such that the pressure in the percussion bladders 39 is increased and decreased, thereby lifting and dropping the patient. The weight of the patient not only shifts the resonating frequency to curve 110 but also adds a biasing force against the percussion bladders 39 preferably distributed through the pad 100. This force correlates with a pressure increase in the percussion bladders 39. The pressure inside the percussion bladders 39 is continuously monitored by the pressure transducers 102 and communicated to the controller 72. As the speed of the pump 50 is changed, the pressure inside the percussion bladders 39 created by patient's potentially changing weight is monitored by the controller 72 to continually adjust for an optimal operating frequency 114 that correlates to a maximum pressure (pressure correlates to force divided by area, and area correlates to amplitude). The controller 72 then operates the pump 50 to achieve the optimal frequency 114 for percussion therapy for that particular patient.
While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention. For instance, the term mattress as applied to mattress 20 is not meant to be limited to a patient's bed, but may apply to any pad assembly that supports all or any portion of a patient against the bias of gravitational forces and whether or not the patient is intended to actual sleep upon the mattress or pad assembly.
In light of the present invention, one skilled in the art would now realize that the bladder 36 may be a passive cushioning member thus generally eliminating the firmness setting device 84 altogether. Such a the cushioning member 36 could be a soft pad and/or made of a homogeneous material similar to the foam or gel of the frame 34. Moreover, the air pump 50 and associated conduits could be replaced with a temperature controlled fluid pump system or a central pump system capable of handling a plurality of beds.