FIELD OF THE INVENTION

The present invention relates to design of a novel sheet metal chassis and assembling means and more particularly, to an integrated chassis assembly for biomedical instrumentations. Further the present invention relates to a method for assembling biomedical instruments and the like on the said chassis.
BACKGROUND OF THE INVENTION

For decades chassis is extensively used for instrument enclosures for desktop, wall mount, portable and rack mounted electronics equipment. Modern instrument enclosures are manufactured with lightweight aluminum using a combination of die-cast, extruded and fabricated parts for easy assembly and attractive aesthetic design. The enclosures include separate anodized front and rear panels for fast mounting of the controls, displays and connectors. Typical applications include medical and wellness instruments, test and measurement equipment, controllers and monitoring systems.

The present inventors have done exhaustive research to come up with a novel chassis design and in the course of such research following prior art documents were studied:

United States letter Patent no. 4276888 provides an apparatus and means to monitor certain vital signs of a patient under medical care where the device is particularly useful in a transport device, for example, an ambulance transporting the patient (perhaps an infant) to or between hospitals, or in transport devices, for example, transporting the infant from location to location within a hospital where it is useful to maintain continuous regard to the patient heartbeat rate, body temperature and oxygen concentration inspired by the patient in the transport device or respirator.

But this monitor when compared to the present invention is very bulky, enclosed in metal cabinet, does not have flat panel TFT display for physiological waveform monitoring. The invention does not provide a mean to monitor capnography related functions. The invention does not provide proper solutions for long-term use, rechargeable battery packs and optimal placing of sub-assemblies in a confined place. The invention does not disclose how to manage the heat generated inside the enclosure and how to pump it out to maintain a comfortable operating temperature. This transport monitor does not have a embedded thermal printer to record the physiological conditions. The monitor does not have the provision to include wireless modules for the communication with external devices for transmission and monitoring of physiological signals.
Yet another United States letter Patent 5024225, Titled "Personal health monitor enclosure" granted to inventor William Fang, filed during 1990, discloses a new type of enclosure. Here the insulated outer plastic enclosure is not provided. The outer surface of the disclosed metal enclosure is uneven without smooth surface and there is possibility of bacteria and germs accumulating leading to nosocomial infection. The design contains Crevices that can accumulate bodily fluids, dirt or grime. The electrostatic charges carried by caregiver can be discharged through metal enclosure. The monitor does not have capnography, invasive blood pressure, body temperature etc. The present invention when combined with outer smooth plastic enclosure can solve this problem.
This invention 5024225 does not provide battery backup, removable battery pack etc while there is a power failure. The physical lock is provided on the chassis for preventing unauthorized access to the interior.
The lacunae in the prior art apparatus described above suggest that there is a need and scope for the design and manufacturing of new type of chassis for biomedical instrumentation.
In the present invention the inventors have provided a chassis upon which the various modules and components are mounted in a strategic manner.
The chassis frame has a horizontal battery bracket upon which another vertical chassis bracket is mounted. The frame and housing are adapted so that the various sub-assemblies, modules, components, cable harnesses are accessible with relative ease so that they are installed, replaced and repaired easily compared with the prior art devices.

The packaging of biomedical modules in a minimum physical volume remains a challenge to the designers of these systems. As the volume decreases, one encounters increased difficulties and expenses in maintenance and repair due to the limited space and greater concentration of components within such systems. Further the extraction of internally generated heat becomes more difficult, a significant problem in view of the relatively low temperatures that must be maintained for reliable performance of the various sub-units of such biomedical instrumentation system.
The patient monitor also should be operable in places that do not have climate control facilities. Apart from that the patient monitor should be quiet in hospital environment for- which new design is needed.
Often additional holding components for instance angle plates are required to hold the components in the desired position of the device. The invention solves the object to provide a chassis for a patient monitoring device, which permits substantial simplified assembly.
OBJECTS OF THE INVENTION
A basic object of the present invention is to overcome the drawbacks/disadvantages of the prior art. According to one object of the present invention there is provided a metal shield chassis for assembly and integration of various biomedical signal-measuring circuits.
According to another object of the present invention is to design a optimized compact chassis using sheet metal for assembly and integration of various biomedical, electro-mechanical, instrumentation modules.
Another object of the invention is incorporating AC to AC conversion power supply module, DC to DC conversion power supply module, lithium ion battery pack, Battery charging and discharging module, thermal printer to get the paper printouts of physiological signals, ECG module, IBP module, Temperature module, NIBP module, pulse oxymeter module, carrier board and mother board with micro controller, wireless communication module into the said chassis described above.

Yet another object of the invention is to design the chassis such a way that all the above modules and components are placed sufficiently close such a way that a compact biomedical instrumentation device is built yet the components and modules are sufficiently placed apart so that the thermal heat generated by one component is not effected on the other or the electromagnetic interference caused by these components does not have the adverse effects on each other by providing various means for the tortuous path which electromagnetic noise must follow to leave or enter the assembly.
Yet another object of the invention is to design and optimize the said chassis such a way that the thermal heat generated by various components is easily vented out to the ambience with natural circulation without the assistance of fan for the forced air cooling and at the same time The creepage and air clearance on PCBs and cables is also appropriately maintained.
Yet another object of the invention is to design and optimize the said chassis such a way that the slots and serrations are provided for cable routing between the said components and modules and also electromagnetic shielding is provided for all the components from the external devices operating nearby.
Yet another object of the invention is to assemble a chassis from pre-galvanized sheet steel for biomedical instrumentation, which is lightweight, hand carried, less than 4000 grams in weight and can be incorporated in to a patient monitor.
Yet another object of the invention is to use thin lightweight mild steel sheets with zinc yellow or blue passivation and build a rugged chassis which can withstand harsh environmental conditions such as moisture, humidity, salty weather, high altitude, vibrations due to road transport, mechanical shocks due to accidental drops. Another objective of the chassis is to hold all the PWA's in place without any damage or detachment to the PCB and cable harness routings even in vibration caused during transit, movement of the patient monitor etc.
Yet another object of the invention is to design an external /field upgradeable battery pack loading and ejecting mechanism which can retain the pack even under adverse conditions.
One more object of the invention is to design a highly conductive metal chassis which acts like a Faraday shield for electro-static charges , external magnetic fields, leakage current, eddy current thereby grounding all these unwanted electric currents to the equipotential ground thus protecting the components incorporated into the chassis as well as the patient connected to the biomedical instruments.
It is another object of the present invention to provide a method of constructing a sheet metal " housing having precisely positioned mounting references so that the assembly time for the entire chassis is less than 20 minutes.
The biomedical electronic devices used require protection from the electrostatic discharge occurring when a care-giver or doctor accumulates an electrostatic charge and contacts a conducting surface of the electronic device. The resulting electrostatic discharge creates capacitively-coupled voltage transients in the digital circuits within the electronic device. The present invention prevents local charge accumulation on the surfaces of such electronic devices
It is another object of the present invention to provide a sheet metal housing which is extremely rugged and reliable, which is relatively lightweight, and which is relatively inexpensive to produce and assemble as compared to conventional housing structures for patient monitor having separately mounted register able components.
A further object is to provide a cabinet structure which provides ample cooling of various components of the patient monitor even when the PMS is in relatively confined structure like ambulance, O.T, CCU, ICU etc. With this the patient monitor can be used in Hospitals, Physician's office, Clinics, During patient transport, Research centers by specialists, Emergency Rooms, Day Surgery Centers, General Surgical Floors, Physicians Offices, Dental Clinics, Emergency Medical Service, Labor and Delivery and Recovery Rooms.
These and other advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
The present invention accordingly comprises the features of construction combinations of elements, and arrangement of parts, which will be exemplified in the construction hereafter set forth, and the scope of the invention will be indicated in the claims. The object of the present invention is also to provide a sheet metal housing with precisely positioned mounting references for accurately locating components.
According to one aspect of the present invention there is provided an integrated chassis assembly
comprising various metal sheet plates fabricated to form an optimized mounting platform forbiomedical instrumentation systems and the like, said assembly comprising: plural bracket means wherein
a first bracket means which secures battery of the system such that the assembly will not tip over or toggle during normal use and a second bracket means in substantially perpendicular relation with the said first bracket means,
said second bracket means being provided with plural cutout means whereby said cutouts are located so that it provides a means for relief for connectors and shortest travel path for interfacing cables between different modules and components assembled on the said chassis Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.

Figure 1 illustrates Part 100 showing overall view of the invented sheet metal housing used for the patient monitor.

Figure 2 illustrates Part 200 showing the overall assembled perspective view of the said invented sheet metal housing assembled and integrated with various modules.

Figure 3 illustrates Part 300 disclosing the perspective view of the battery bracket, battery pack, ejection and engagement mechanism, the plug-in/sliding/ejection mechanism of battery pack, the battery charger card, battery cover etc.

Figure 4 illustrates the partial cross section with exploded perspective view of an illustrative chassis in accordance with an embodiment of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

By the term "substantially" it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

Sheet metal is metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Sheet metal is available in a variety of thickness and its thickness is called its gauge. The gauge of sheet metal ranges from 30 gauge to about 8 gauge. The higher the gauge, thinner is the sheet metal. The thickness is also measured in millimeter. For example the metal sheets used in this invention are approximately 1.2 millimeter thick.
Many metal materials are available in sheet metal form, such as aluminum, steel, brass, copper, tin, nickel and titanium, high permeability materials such as mu-metal, permalloy used for shielding at low frequency magnetic field.

Sheet metal comes in flat pieces or a coiled strip. Running a continuous sheet of metal through a roll slitter forms the sheet metal coils. Sheet metal can be cut, punched, bent, welded and rolled to form all different structures.

Stamping includes a variety of sheet-metal forming processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining. The stamping process produces sheet metal parts by the quick downward stroke of a ram die that is in the desired shape. The machine is called a punch press. The punch press can "punch" holes of different sizes and shapes, cut metal, or form a variety of shapes.

The sheet metal fabrication utilizes precision laser cutting, CNC press brake forming, CNC punching, shearing and standard welding technologies.

Sheet Metal Fabrication Process disclosed in this invention can be divided into 7 steps.

1. Selection of Sheet Metal Material
2. CNC Machine Programming
3. Shearing Metal Sheets
4. Punching Holes
5. Folding Sheet Metal into Shape
6. Hardware Insertion
7. Product Finish

In order to optimize strength, manufacturing capability and cost, materials for sheet metal enclosure is chosen carefully. The most popular choice of materials for sheet metal enclosure is aluminum and cold rolled steel. Aluminum makes for a lightweight enclosure or chassis, but is expensive.

Cold rolled steel is very strong and inexpensive, but it is heavy. Also since steel rusts, all cold rolled steel enclosures must be finished with plating, traditional painting or powder coating. Another choice of material is galvanized steel (steel coated with zinc for corrosion resistance).

CNC Machine Programming

The major manufacturing steps involved in making sheet metal enclosures is sheet shearing, hole punching and press brake folding. All these steps are done on computer controlled CNC machines. The first step is to convert a sheet metal enclosure design into flat patterns as if the part was unfolded. The next step is to determine bend allowances and offsets for their particular machines.

Punching Holes

Holes in sheet metal are punched in a large computer controlled punching machine. These punches provide a multi-station turret where all the different punch sizes and shapes required for the chassis can be stored.

The sheared-to-size sheet is loaded and indexed to a 0,0 corner and the punch then shifts the sheet rapidly to the different x-y coordinates and punches the appropriate sized hole, including counter sinks and threaded extrusions.

The hardware inserts can be inserted automatically by the punch press. This is computer controlled and good accuracy is easily achievable across the part.

Folding Sheet Metal into Shape

The punched metal is folded to shape in large press brakes, which, like the shear and punch, are computer controlled.

Hardware Insertion

Depending on the material, hardware may be installed now or after the part is finished. For steel parts to be painted or plated, the hardware is pressed in now.

Generally a PEM type insert is used to provide high-strength screw threads, both as internally threaded nuts and as studs. PEM stands for Penn Engineering and Manufacturing Corp.

Product Finish

Sheet metal enclosures are basically finished with four processes: anodizing, plating, painting or powder coating. Silk screening can be done lastly.

Aluminum can be painted, powder coated or anodized. Anodizing converts the aluminum surface to Aluminum Oxide, which is very durable.

Steel rusts and must be protected. There are several types of plating are available with the most common being zinc and nickel.

The working of this invention with a method of assembly (constructional features) can be easily understood by referring to the accompanying drawings Fig 1, Fig2, Fig 3, Fig 4.

The Fig l,Part 100, discloses the new bare chassis constructed with plated / passivated galvanized sheet metal , studs, rivets , welded joints, punched cutouts, self tapping threaded inserts, cast inserts, pressed-in threaded insert, self locking threaded inserts, expansion inserts,

The Chassis Assembly in Fig. 1 contains two Main components: First Bracket i.e. Battery Bracket (118) and Second Bracket i.e. Chassis Bracket (104).

The part 118 is the battery bracket where the center of gravity lies so that it will stand upright on a flat surface. The design is such that the System will not tip over on a 5-degree inclination when in any position of Normal Use. The part 118 is fabricated by taking a pre-cut stairfless steel or any other suitable metal sheet selected from 6061 aluminum, ASTM 316 grade non-corrosive steel, Zinc, copper and magnesium alloys. Electro galvanized cold rolled (SECC) steel is also a desired choice.

Fig. 4 discloses the detailed flowchart of the step-by-step fabrication of the chassis disclosed in Fig.l.
The Battery Bracket (118) is fabricated as follows:

The design of the sheet metal is fed to the Computer numerical controlled (CNC) Machine.

- During the first step 402, a CRCA Sheet stock with thickness 1.6 millimeter preferably with 'D' grade material characteristics is taken and clamped on to the fabricating machine. For the preferred embodiment described in this invention zinc plating with blue passivation of 12 to 15 micron thickness is done.

- During the next step 404, the slots shown in 116 are pierced; these slots are given for dissipating the heat generated by the components (as shown in Fig 2) in the Patient monitor unit and it also serves as a means in reducing the weight of the chassis without compromising on the strength and rigidity. The edges of the slots are bent inwards of the cavity 118. These raised edges will help the battery pack 234 to slide inside the 118. The dimension of typical slot can be 4 mm width, 35 mm length in one case or 10mm width and 44 mm length in another case.

The dimensions of these slots are accurately cut such a way that only heat radiation goes out of the chassis but the electromagnetic waves will not go out or enter inside the chassis. For this, the width of the slots 116 is less than "half wavelength" of the interfering electromagnetic wave.

With these steps the battery-pack receiving compartment 118 is formed. The length of this battery bracket is 208 millimeter, the width is 94 millimeter and the height is 50 millimeter approximately.

During next step 406, all other holes for TSF's( 140) are also pierced one by one. The indexing holes are punched next. The EMI Power inlet cutout 128 is also cut open for the required dimension, which is 20 mm and width is 28 mm approximately.

After this 4 small and 1 larger hole in 130 are punched for Equi-potential Earth, where all the chassis earths are grounded. (The earthnut 248 is threaded to part 130 later on).

- The length of this power inlet plate is 44 mm, height is 60 mm approximately.
- After piercing, the component outer profile is blanked out.
- Once the component is blanked, it is bent (by means of a bending tool) near TSF locations 122 and 140 to form the guide for the battery to enter.

- During next step, it is bent near 108/124 also to align with the back panel cutout for power inlet and Equi-potential earth.

- A Bend at 112 is done as means for accommodating the side connector panel. Later, gussets are provided near 108 for strengthening of chassis.

- During next step 408, the TSF (140 and 122) fixing is done by means of using a TSF fixing tool.

- At 132, one small bracket is indexed and welded for holding the earthnut. The dimensions of this bracket are height -12 mm and the width is 33 mm approximately.

This completes the manufacturing of battery bracket component Chassis Bracket (104):

- As a first step 410-Fig 4, the design of the sheet metal is fed to the Computer numerical
controlled (CNC) Machine.

1.6 mm thick CRCA Sheet stock preferably with 'D' grade material characteristics is taken and clamped on to the fabricating machine

- During next step 412-Fig 4, cutouts 110 are pierced for providing a means of relief for the connectors, which are connected to the carrier board. The interface cables running between modules and components are passed through these cutouts with a shortest distance possible. The metal plates of chassis, surrounding these cables are means for shielding from electromagnetic noise emission

- All the relief holes and holes for TSF (102 ,114 ,134) are also pierced.

- The component is blanked out after all the piercing.

- During next step, the component is bent near 138, for a means of accommodating Power supply, jack able modules and for indexing purpose. With this a side plate 136 is formed. The height of this side plate is 188 mm and width is 79 mm approximately.

- During the next step 414, one more bend near 126 is for strengthening, assembly to battery bracket and accommodating a C02 module. The length of this plate formed is 115 mm and width is 37 mm.

- Two more bends near 106 which are means for fixing it to the rear plastic enclosure /panel of the machine (outer plastic enclosure is not shown for simplicity) and also for holding the connector panel assembly in place. This bracket 106 also can be used as a means to mount miniature Wi-Fi (Part 254 in Fig 2) or any wireless module away from all the components of the chassis. The dimensions of this plate are 22 mm height and 11 mm width.

- Later on 3 gussets are given near 108, 138 as a means for strengthening the respective bent sections.

- The TSF's are fixed near 134,102,114,122,102,140 plate 126 and all other places where required to mount the modules.

This completes the manufacturing of chassis bracket component. The additional cutout sheet 126 is mount with TSF for C02 module 238. The dimensions of this additional plate are 45 mm length and 78 mm width.
Zinc plating with blue passivation of 10-12 Microns is done for the entire assembly.

The part 118 is a cavity formed to receive a battery pack (234 in Fig. 2) with blind mating connectors and springs at 304. The battery pack is inserted and ejected using suitable mechanical release means.

The part 112 is another plate with threaded inserts to receive and hold connector plate 208/ Fig 2. This is substantially perpendicular to the surface of the 118. The part 136 is precisely cut plate used for mounting the communication card 244, AC to DC power conversion module 250. This plate is mounted perpendicular to the plate 118 and plate 104.

This plate 136 can also be used to mount a thermal recorder ( not shown) with paper roll, which gives printout of waveforms and numeric of the patient's vital sign. The part 106 is mounted with right angle to plate 104.

The hatch lines 146 on plate 136 are small copper heat pipes may be with diameter 3 millimeter and vary in length. These are used to carry excess heat generated by power supply 250 to the top surface of the chassis. A small fan also can be mounted on the slot 110 on plate 136 to exhaust the heated air on 250 to the exhaust on the top. This fan ( not shown) mounted on the slot 110 and surrounded by the copper tubes 146 will suck the hot air from the remote location from the power supply 250 and will be exhausted to the top portion of the chassis.
This plate 104 is used for mounting of the non-invasive blood pressure module 240/Fig 2. The dimensions of this plate are 154 mm height and 208 mm width.
The plate 126 is another plate with threaded inserts and mounted substantially parallel and on top surface of the 118. This plate 126 is used as means for mounting the non-invasive respiration and carbon dioxide gas analysis and monitoring module part 238.
This module is also known as "capnography module". This module allows for measurement of inspired/expired carbon dioxide and respiration rate on patients in the Operating Room, ICU, NICU, Transport and Emergency treatment. The method for measuring CO2 is based on non-dispersive IR absorption of the CO2 in the breath sample.

Part 134 is a threaded insert riveted on the plate 136 and having threaded receptacle to receive standard M4/M6/M8 type screws. This is shown by way of an example. Plurality of The similar rivets can be fixed on the chassis precisely for mounting the components. The top of this 134 can be covered with various types of caps and bushes made from resilient /shock absorbing /electrically insulating material like rubber, neoprene to protect the modules mounted from mechanical shock.
The part 120 is a 'U' shaped beryllium copper spring soldered on the sidewall 124 of the chassis. When the entire chassis assembly that is disclosed in Fig. 2 is covered with outer most plastic enclosure, the spring 120 will make contact with the inner conductive surface of the said enclosure. This will ground the outer enclosure and provides shielding effect. For the sake of simplicity this outer enclosure is not shown.
The Engineering product design of chassis in this invention is done is such a way that the modules are jackable on carrier board 204 which enables ease of assembly and service.
The carrier board 204 is fixed to the chassis by means of assembly screws. The modules like
ECG, IBP and Sp02 jacks on to the 204- carrier board. The 202 (SOM- system on motherboard)
are mounted on the carrier board 204.
The connector Panel assembly 208 and connector PCB 226 are jacked into the carrier board 204,
after which it is fixed to the chassis with screws at TSF location 114 of 112. The chassis is also
designed for easy assembly and serviceability. All the modules are independently accessible and
replaceable.
Uniqueness of this chassis is it has only 3 metal sheet sub-components 118,136,104 which are spot welded to each other.
Part 144 are gaskets made from electrically insulating material like silicone rubber, plastic, semi-conductive sponges which can absorb ESD and EMI. These are provided for the slots 110 where the interfacing cable harnesses crisscross through these slots.
Since the plates 104,136 and 118 are at ground potential because of the 248 -earth connector, the cable harness passing through these slots 110 will be touching the harness. Since this chassis is designed for patient monitoring equipment, a high degree of electrical insulation or galvanic

isolation is needed between input and output connectors. When the above-mentioned cable harnesses carry the HV surges or transients there can be insulation breakdown due to the same potential appearing between the earthed chassis and the cable harness. Similar gaskets with multiple properties like thermal conductivity, porous structure for air movement can be deployed for additional benefits.
Although in the preferred embodiment described above, the sheet metal parts 104, 136, 126, 118,112, 106 are fabricated with steel and other metal alloys, the same can be constructed using other innovated substitute material also. By way of an example the plates 104, 136,126, 118,112, 106 can be fabricated using FR-4 grade phenolic printed circuit boards commercially available as "copper clads". The electro-plated copper layers on these printed circuit boards acts as an excellent heat dissipater. With this, the plates 104, 136, 126, 118, 112, 106 can'be used for directly mounting individual electronic components and modules other than using as structural support. These copper claded / un-etched printed circuit boards are lightweight and easy to cut and drill compared to sheet metal.
Fig 2 shows the perspective view of the same chassis with all the components assembled.
(This is also step 416 in Fig 4 part 400)
Part 204 is the carrier board containing most of the electronic components. The SOM mother board 202 containing micro-controller, memory chips with firmware is mounted on the 204.
Part 206 is PCB mounted threaded inserts used for mounting 204 on to the 104.
Part 234 is a battery pack with precise dimensions so that it easily inserted in to the cavity 118 and ejected. This pack contains a status indicating lamp or LED part 232. Part 228 is the battery cover to conceal the pack 234. Part 230 is a transparent window made from clear plastic or glass or epoxy potting. The presence of the battery and the charging status Lamp 232 is clearly visible through 230.
Part 246 is electrical socket for receiving mains power through a suitable chord. This is firmly fitted on the part 128. Part 248 is metal stud connector with high conductivity. All the grounding points of the modules are finally brought to this connector and it is grounded. The electrical resistance measured between the 248 and any metal part of the chassis Part 100 will be less than

200 milli ohm to avoid potential difference on the chassis. An equi-potential earthing cable with a alligator type clip is connected to 248 at one end and buried inside the conductive earth pit on the other side (not shown).
The connector panel 208 is used for connecting various cables like electrocardiograph, nasal cannula/sampling line, temperature probes, invasive blood pressure cable, hose for non-invasive blood pressure measurement etc. The various possible connectors are shown.
Part 210 is yellow colored, round, 12 pin connector for which a pulse oxymeter -finger probe sensor can be connected.
Part 212 is RED colored, round, 12 pin connector for which a invasive blood pressure sensor can be connected.
Part 214 is a round pink colored metal or plastic pneumatic connector for which a blood pressure cuff can be connected.
Part 216 is a white colored pneumatic exhaust port connected through a tube with .Capnograph module 238.
Part 218 is GREEN colored 12-pin connector by means of which a electro cardio graphic cable can be connected and physiological signals related to heart can be acquired.
Part 224 is a pneumatic input sampling connector, which draws exhaled gas from the nose of the patient and supplies to capnography module 238 for breath analysis. The exhausted gas from 238 is vented to ambient by exhaust port connector 214.
Part 220 and 222 are two phono /audio sockets used to connect thermistor based temperature probes to the body of the patient.

Part 226 is a printed circuit board (PCB) mechanically fixed on the back side of part 208 so that all the mentioned connectors 210,212,214,216,218,220,222,224 are seated on this PCB. The electrical connections also run from these connectors through this PCB 226 and distributed to various modules, motherboard assembled on the chassis Part 100.

The PCB 226 is also used for mounting the SP02 (pulse oxymeter) signal acquisition board to which yellow connector 210 is connected.

The part 242 is a blind mating / drawer type panel mountable connector on PCB 244. The battery pack 234 will engage with this for charging/discharging from 244 and providing uninterrupted power to the all modules

The PCB- 244 also contains connectors and associated circuits as below.

a) 4 pin USB-external PC (personal computer) interface connector,"

b) 9pinRS232 for Wired CNS using RS232 protocol

c) 3 pin audio sockets used for ECG and respiration synchronization signals, These signals are used by lithotriptor while breaking kidney stones and for defibrillator for providing synchronized shocks with ECG

d) 3 pin power connector used for providing external DC supply to the patient monitor when the battery backup is not sufficient during prolonged transportation of patient in ambulance.

The various slots 110, are provided in the chassis such a way that the interconnection between various modules disclosed in Fig. 3 is possible with shortest route.

The heat and EMI generating modules like power supply part 250 is kept away from other noise sensitive components and the metal sheet surrounding it will provide a electrical and magnetic shielding.
The various novel features can be included to the chassis described in Fig 1 can be as follows. The chassis can be painted with EMI and Heat absorbing material to maximize the thermal capacity. The chassis surface can be made into matt finish or fine serrations as shown in PART 142, so that effective surface area can be increased similar to heat-sink surface.

The additional mounting plate 252 can also be designed to have the serrated surface like 142 or heat carrying copper tubes 146. Since power supply 250 is the maximum heat generating component the absorption of heat is essential.

The PCB 236 is an external LCD display monitor interface with HDMI type hi-resolution video connector.

The part 254 in Fig. 2 is the wireless communication module interfaced with the carrier board 204 and mother board 202. This is placed in a location where the obstacles due to metal shield and the electromagnetic interference due to nearby modules and components is minimum.

With the above novel design the invention can withstand following tests.

(These are also part of the Step 420, Fig 4)
The shock test with peak acceleration of 50 G, with pulse shape half sine and number of shocks 10 times on the entire three axis. The sinusoidal vibration test with frequency range 10 to 500 Hz and acceleration amplitude 1 G and type and duration of endurance 10 sweep cycles in each of the three axes (2 hours duration for each axes).
The random vibration wide band test with frequency range 20 to 500 Hz and acceleration spatial density being 0.02 g 2/Hz for the duration of 9 minutes. The random vibration broad band test with frequency range of 10 Hz to 2000 Hz and resolution being 10 Hz acceleration.

Acceleration amplitude: 10 hz to 100 hz: 1.0 (m/s2) 2/Hz lOOhz to 200hz: -3db/Octave 200hz to 2000hz:0. 5 (m/s2) 7hz.

Duration: 10 min per each perpendicular axis (3 total) The system will also pass the impact test as per prevailing standards.

With this new invention the operating environment is as follows.

Operating temperature : 0 to 60 °C Operating humidity : 10 to 90% RH(Non condensing) Operating pressure : 500 to 900 mmHg.

Altitude : 3100m (around 10,000ft)

Fig. 3 shows the exploded perspective view with partial cross section of the battery bracket and the battery pack connector.

(This is also part of the step 418, Fig 4)

To insert the fresh battery pack, the pivoted cover 228 is opened. The battery pack 234 with the blind mating / drawer type connector 306 is inserted such a way that the connector 306 is mechanically registered and mated with the PCB mounted connector 242. The spring loaded/retractable cover 228 can be manufactured using semitransparent polycarbonate plastics so that the status Lamp 232 is visible through 230 and at the same time environmental protection to the pack 234 and for the interior of the chassis is provided. The pack 234 to be held firmly in its position while remained in connection with the connector 242. Also the pack should eject quickly when there is need to remove the pack 234.

The pack is also subjected to all types of transport related vibrations caused by trolley, ambulance and physical jerks during hand-carrying etc.

Also, the chassis design is such a way that the connector 306 to be properly mated with 242, without the person seeing it from outside.

This is achieved with the help of two spring-plungers 304 mounted on either side of the 242.

The channels fabricated inside the 118 will guide the pack 234 to travel up to 242 where the flat surface of the battery will touch and push the spring-loaded plungers 304. At the same time the connector 306 will enter inside the connector 242. The mating of the connector pair 306 with terminus receiving cavity inside 242 and the plunger reaching the end of travel will happen simultaneously so that the pack is locked and will remain in that position. When the pack is pushed again, the plunger 304 is released from its position and will uniformly eject the pack 234 out of the cavity. Pressing near the transparent window 230 of the cover 228 can also do the pushing of the pack.

In the prior art products these features were not available and a nylon cord located near 232 was used to manually pull the pack.

The electrical terminus connections between 242 and 306 contain the following

a) Power input from the DCDC power supply 244 for charging the pack 234.

b) Power output from the battery pack to discharge the pack 234 and to provide the uninterrupted power to DCDC 244,carrier board 204,SOM 202,modules 240,238,236 and any other external module or sensor connected through 208 and 244

c) Signal connections comprising battery temperature monitoring, battery usage detection in terms of hours and number of times the battery pack ejected /inserted, over-charge, over-discharge including short circuit detection, battery charge status.

d) Signal connections comprising Pack Type /model/Ampere-hour capacity detection

The DCDC card 244 will communicate with pack 234 and will charge it when mains power is available at 246.

The Assembly of the various components for the disclosed chassis in Fig. 2 Part 200, is as follows,

The assembled chassis as shown in Fig.l, Part 100 is taken for assembly.

The Power socket Part 246 is taken and snapped into the cutout. Next to this, there is a hole 130 where an earthnut 248 is inserted from outside and fastened with a nut from inside. During the next step carrier board 204 is taken and assembled on 104 using 7 pieces of M3x8 Assembly screws. The SOM module 202 is assembled on the 204. During the next step, the ECG analog signal acquisition board is assembled on the motherboard 204(backside) and fastened using a 3nos. of M3x8 Assembly screw.

The optional physiological parameter boards Viz. Invasive blood pressure ( IBP) and SP02 module (backside of 204) are jacked into the carrier board 204 and fastened with M3x8 assembly screws.

The Baseboard is inserted into the connector. The assembled ECG board (optional) is jacked into the motherboard IBP (optional) is jacked and fastened with a. Sp02 is also jacked into the Motherboard PWA and fastened with 3 assembly screws. The connector Panel sub assembly is jacked into the carrier board 204 and fixed to the chassis 104 and 112 with 3 assembly screws. The DCDC PWA (post wave soldered assembly means the PCB soldered, with all the components) 244 is jacked into the carrier board 204 and is retained by 4 assembly screws from the other side. The DCDC plus (optional), which is attached to 244 is also jacked into the carrier board 204 and retained by a M3 assembly screw.

During the next step the NIBP module 240 is taken and fastened to the chassis with 4 Nos. of M3x8 assembly screws. After this the C02 capno graph module 238 is fastened to the chassis using 3 assembly screws. During next step the power supply (ACDC) 250 is fixed to a adaptor plate 252 and the subassembly is fixed to the Chassis 136 using countersunk screws.

The HDMI- external display module 236 is assembled to the chassis by M3 screws. One cable harness from AC-DC module 250, which goes to the carrier board 204 is assembled. One cable harness from power in let 246 to AC/DC converter 250 is assembled. One silicone rubber tube of diameter 4mm will be connected between the NIBP modules 240 to the pneumatic connector 214.

The NIBP module 240 and the C02 module 238 are interfaced with carrier board 204 using flat ribbon cables passing through the slotl 10.

WE CLAIM:

1. An integrated chassis assembly comprising various metal sheet plates fabricated to form an optimized mounting platform for biomedical instrumentation systems and the like, said assembly comprising:

Plural bracket means wherein a first bracket means which secures battery of the system such that the assembly will not tip over or toggle during normal use and a second bracket means in substantially perpendicular relation with the said first bracket means, said second bracket means being provided with plural cutout means whereby said cutouts are located so that it provides a means for relief for connectors and shortest travel path for interfacing cables between different modules and components assembled on the said chassis.

2. The integrated chassis assembly as claimed in claim 1 wherein said first bracket means comprising center of gravity of the assembly such that the assembly will be prevented from toppling during normal use with an inclination of about 5 degrees.

3. The integrated chassis assembly as claimed in claim 1 wherein said first bracket means comprising plural slots or openings and/or heat carrying miniature copper tubes for dissipating any heat produced by the modules and/or components during operation.

4. The integrated chassis assembly as claimed in claim 3 wherein said slots comprising inward bent edges which help to slide the battery pack inside the bracket.

5. The integrated chassis assembly as claimed in claims 3 and 4 wherein said slots having width less than the half the wavelength of interfering electromagnetic waves.

6. The integrated chassis assembly as claimed in claim 4 wherein the said bent edges adapted to protect the electromagnetic waves from going out or entering the chassis.

7. The integrated chassis assembly as claimed in claim 1 fabricated from various preciously cut sheet metal plates to form an assembly.

8. The integrated chassis assembly as claimed in claim 1 wherein said first bracket means is made from a metal sheet selected from a group comprising stainless steel, 6061 aluminum, ASTM 316 grade non-corrosive steel, Zinc, Copper, Magnesium alloys and Electro galvanized cold rolled (SECC) steel or Cold rolled grain oriented (CRGO)

9. The integrated chassis assembly as claimed in claim 1 wherein said first bracket means further comprising a bend to accommodate a side connector panel.

10. The integrated chassis assembly as claimed in claim 1 wherein said second bracket means comprising plural metal plates for securing the cables from electromagnetic noise emission.

11. The integrated chassis assembly as claimed in claim 1 wherein said second bracket means comprising side plate means for accommodating power supplies, jack able modules and for indexing purpose and the like.

12. The integrated chassis assembly as claimed in claim 1 wherein said second bracket means further comprising another bend for strengthening assembly to said first bracket means and accommodating a C02 gas analyzer module.

13. The integrated chassis assembly as claimed in claim 1 wherein said second bracket means further comprising further two bends for fixing the chassis assembly to a rear plastic enclosure or a panel of a machine.

14. The integrated chassis assembly as claimed in claim 13 wherein said two bends form bracket for mounting any wireless module away from other components of the chassis.

15. The integrated chassis assembly as claimed in claim 1 wherein said first bracket means comprising a beryllium copper spring with substantially U shaped.

16. The integrated chassis assembly as claimed in claim 1 wherein said first bracket means comprising a cavity designed to cooperate the charging and discharging of the battery.

17. The integrated chassis assembly as claimed in claim 16 wherein said cavity is mechanical vibration free.

18. The integrated chassis assembly as claimed in any of the preceding claims comprising fabrication so as to selectively mount a battery pack cavity, power supply, capnography module, mother board, blood pressure module, ECG module, Pulse oxymeter module, inter device communication card , connector panel or any combinations thereof.

19. The integrated chassis assembly as claimed in any of the preceding claims for mounting a device comprising a plurality of functionally interconnected biomedical signal acquisition modules, processing, displaying components and modules along with the power supply, thermal recorder, rechargeable battery pack, wireless network communication module, WI-FI connectivity in any combination thereof.

20. The integrated chassis assembly as claimed in any of the preceding claims comprising an integrated patient interface connector plate means selectively comprising yellow colored 12 pin pulse oxymeter sensor connector, Red colored 12 pin invasive blood pressure sensor connector, quick hose release-non invasive blood pressure cuff connector, Green colored 12 pin ECG sensor connector, white colored gas exhaust connector, black colored clinical temperature sensor connectors, Grey colored exhaled respiration gas sampling connector and combinations thereof.

21. The integrated chassis assembly as claimed in any of the preceding claims comprising a plug-in and removal rechargeable battery with capacity 6000 milli-ampere-hour approximately.

22. The integrated chassis assembly as claimed in any of the preceding claims' comprising indications for battery charging.

23. The integrated chassis assembly as claimed in any of the preceding claims wherein user operated connector panel assembly is ergonomically placed on the right side of the chassis, and heat generating power supply is placed on the left side.

24. The integrated chassis assembly as claimed in any of the preceding claims wherein the sheet metal plates further comprising anodized mat finish and/or with fine aberrations to increase the surface area of the plate for heat dissipation.

25. The integrated chassis assembly as claimed in any of the preceding claims wherein the plates are coated with heat absorbing paints and / or electromagnetic absorbing paints.

26. The integrated chassis assembly as claimed in any of the preceding claims comprising a swing able battery cover, which is also semitransparent.

27. The integrated chassis assembly as claimed in any of the preceding claims withstands peak acceleration of 50 G , sinusoidal vibration test with frequency ranging from 10 to 500 Hz and acceleration amplitude 1 G approximately.

28. The integrated chassis assembly as claimed in any of the preceding claims withstands random vibration wide band test with frequency ranging from 20 to 500 Hz, Operating temperature: 0 to 60 °C, Operating pressure: 500 to 900 mmHg and Altitude: 3100 m approximately.

29. The integrated chassis assembly as claimed in any of the preceding claims where the sheet metal plates are substituted by un-etched, copper clad printed circuit boards so that the electronic components and modules can be directly soldered on the chassis

30. The integrated chassis assembly as claimed in any of the preceding claims adapted to be used in patient monitors required to address Emergency Rooms, Day Surgery Centers, General Surgical Floors, Physicians Offices, Dental Clinics, Emergency Medical Service, Labor, Delivery and Recovery Rooms and the like.

31. Method of assembling the said integrated chassis assembly comprising various metal sheet plates fabricated to form an optimized mounting platform for biomedical instrumentation systems and the like as claimed in any of the preceding claims comprising,

Forming a cavity for battery pack, bending and forming the metal sheets to form side plates by means of which various bioinstrumentation modules are carried by said frame to form a substantially simplified assembly.

32. An integrated chassis assembly comprising various metal sheet plates fabricated to form an optimized mounting platform for biomedical instrumentation systems and the like as herein . described and illustrated with reference to the accompanying drawings.

33. Method of assembling the said integrated chassis assembly comprising various metal sheet plates fabricated to form an optimized mounting platform for biomedical instrumentation systems and the like as herein described and illustrated with reference to the accompanying drawings. plates fabricated to form an optimized mounting platform for biomedical instrumentation systems and the like. The assembly comprises a first bracket means (118) which secures battery of the system such that the assembly will not tip over or toggle during normal use and a second