WO2012119000A1

WO2012119000A1 - Safety shield and centrifuge assembly having the same

Info

Publication number: WO2012119000A1
Application number: PCT/US2012/027330
Authority: WO
Inventors: Toby BALLEN; Thomas Creazzo; Hiroshi POWELL; Felicia Celaru; Teodora TASTAMAN
Original assignee: Siemens Healthcare Diagnostics Inc.
Priority date: 2011-03-02
Filing date: 2012-03-01
Publication date: 2012-09-07

Abstract

A protective, safety shield for use with a centrifuge to provide a safe, energy-dissipation path when the centrifuge undergoes catastrophic failure. The shield includes a shield portion in combination with door latches and pins, which are adapted to provide a pathway for transferring the inertial crash energy into a frame subsystem in order to protect the operator (s) from the sudden and violent release of energy.

Description

TITLE OF THE INVENTION SAFETY SHIELD AND CENTRIFUGE ASSEMBLY HAVING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR

DEVELOPMENT

Not Applicable BACKGROUND OF THE INVENTION

The present invention concerns a centrifuge assembly and, more particularly, a protective shield that is structured and arranged to contain energy released during a catastrophic failure of a centrifuge that is contained or retained within a centrifuge assembly.

The failure of a centrifuge occurring, for example, at an operating speed of up to 4500 revolutions per minute (RPM) results in the release of a significant amount of energy that can cause catastrophic damage to the centrifuge and, in some instances, injury and/or possible loss of life. In previous, integrated centrifuge systems, energy dissipation from a catastrophic failure could cause components in a destructive path to suddenly and unexpectedly become projectiles that could cause injury or death.

A stand-alone centrifuge typically dissipates crash energy by spinning freely on the floor or other surface within a protected area until the centrifuge comes to a complete stop. Conventional centrifuges that are restrained or constrained within a system, however, are not free to dissipate inertial energy in a similar manner, which is to say by spinning in a protected area. Consequently, it would be desirable to integrate a protective/safety shield into a system for a restrained/constrained centrifuge in order to contain the released energy from a catastrophic failure by directing the energy into the sub-system chassis, thereby protecting the operator (s) from harm or injury.

BRIEF SUMMARY OF THE INVENTION

A protective, safety shield for use with a centrifuge assembly is disclosed. The shield is structured and arranged to provide a safe, energy-dissipation path when the centrifuge undergoes catastrophic failure. More specifically, the shield includes a shield portion in combination with door latches and pins, which are adapted to transfer the inertial crash energy into a frame sub-system in order to protect the operator (s) from the sudden and violent release of energy.

The centrifuge is at least one of constrained and retained in a constraining/retaining system that includes a sub-system frame having a first, slotted block and a second block that are releasably attached to the sub-system frame and a door that is rotatably attached to the sub-system frame. The protective, safety device includes a first latch assembly that is releasably attached to the door at a first end, proximate the first, slotted block; a second latch assembly that is releasably attached to the door at a second end, proximate the second block; a shield portion that is releasably attached to the door and the first latch assembly at the first end and releasably attached to the door and second latch assembly at the second end; and a latch release assembly that is disposed on the door and operatively coupled to the second latch assembly, the release assembly is structured and arranged to open or to close and lock the second latch assembly about the second block.

The first latch assembly includes a plurality of engagement pins that are structured and arranged to interface with corresponding channel portions in the first, slotted block, to fully engage the corresponding channel portions when the door is in a closed state. The second latch assembly includes a latch locking member that is adapted to engage the latch pin of the second block, to lock the door or, alternatively, a plurality of engagement pins that are structured and arranged to interface with corresponding channel portions in the second block to fully engage the corresponding channel portions when the door is in a closed state. A signal device is adapted to interface with a sensing device integrated in the second block.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS Other features and advantages of the invention will be apparent from the following description of the preferred embodiments thereof and from the claims, taken in conjunction with the accompanying drawings, in which: FIG. 1 shows a diagrammatic view of a constraining/retaining system with a closed door in accordance with the present invention;

FIG. 2 shows a diagrammatic view of the constraining/retaining system of FIG. 1 with an open door in accordance with the present invention; FIG. 3 shows a diagrammatic view of a first latch assembly with an upper pin engaged in an upper channel of a slotted block in accordance with the present invention;

FIG. 4 shows a diagrammatic view of the first latch assembly of FIG. 3 in accordance with the present invention;

FIG. 5 shows a diagrammatic view of a second latch block having a latch pin and sensing device in accordance with the present invention;

FIG. 6 shows a diagrammatic view of the second latch block of FIG. 5 and a second latch assembly in accordance with the present invention;

FIG. 7A shows a diagrammatic view of the second latch block of FIG. 5 and a latch release assembly in accordance with the present invention;

FIG. 7B shows a diagrammatic view of the second latch block of FIG. 5 and a latch release assembly in accordance with the present invention; and

FIG. 8 shows a diagrammatic view of the latch release assembly of FIGs. 7A and 7B.

DETAILED DESCRIPTION OF THE INVENTION

Appendix A (below) provides assumptions and estimates of the energy, forces, and displacements associated with a catastrophic crash event of a constrained/retained centrifuge, for example a Hettich Centrifuge manufactured by Andreas Hettich GmbH & Co . of Tuttlingen, Germany, that are necessary for the design of a protective/safety system for a constraining/restraining centrifuge assembly. In order to contain the damage and to prevent injury or loss of life, a protective/safety system for the centrifuge should be integrated into a containing/restraining centrifuge assembly that is capable of withstanding and/or accommodating the energy, forces, and displacements. Although, the actual magnitude of the forces and/or displacements resulting from an incident may not be the same (i.e., may be greater than) those from the calculations, a suitable factor of safety included in the design provides an additional degree of confidence and security against failure. Indeed, the designed constraining/restraining assembly and constrained/ restrained centrifuge can satisfy the IEC/EN 61010-2-10 safety standard for stand-alone centrifuges.

Referring to FIG. 1 and FIG. 2, there is shown a constraining/retaining centrifuge assembly 10 for use with a constrained/retained centrifuge (not shown). The system 10 includes a protective door 12, which is shown closed in FIG. 1 and shown open in FIG. 2, and a structural frame sub-system, i.e., a system chassis 15. The door 12 is structured and arranged to transfer inertial crash energy to the system chassis 15 in order to protect the operator (s) from the sudden and violent release of energy resulting from catastrophic failure of the centrifuge. The system chassis 15 is designed to support and house the centrifuge as well as to carry vertical, horizontal, and transverse forces, moments, and displacements that may result from a catastrophic event occurring in the constrained/retained centrifuge.

The structural portion of the system chassis 15 can include a plurality of supporting pads 18 that are structured and arranged to support the centrifuge and to transfer dead load from the centrifuge to the frame 15. The system chassis 15 further includes a plurality of mounting brackets 11 and 13 that are adapted to releasably attach sliding shelves (not shown) to the system chassis 15. The door 12 is rotatably attached to the system chassis 15 at an upper 17 and a lower 16 hinge device. Additional hinge devices can be added if desired. The door 12 can be made from sheet metal or from a hard plastic. A plurality of openings, i.e., vent holes 67 (denoted in FIG. 6), can be provided in the door 12.

Attached to or integrated into an inner face 12a of the door 12 is a protective shield 20. The shield 20 can be made from a single piece of heavy gage, cold, rolled steel or from multiple pieces of heavy gage, cold, rolled steel. The shield 20 is provided to transfer loads from the centrifuge to the system chassis 15. More specifically, to transfer loads resulting from a catastrophic failure of the centrifuge to the system chassis 15.

FIG. 3 shows an illustrative embodiment for attaching the shield 20 to the inner face 12a of the door 12. Those of ordinary skill in the art can appreciate that there are a myriad of ways to attach the shield 20 to, or to integrate the shield 20 with, the door 12. According to the embodiment shown, the shield 20 can be fixedly attached, e.g., welded, to an L-shaped section 29 that is releasably attached to a first end of a mounting bracket 28, e.g., via a fastening device 21a, e.g., a screw, bolt, rivet, and the like. The second end of the mounting bracket 28 is fixedly attached, e.g., welded, to a peripheral edge of the inner face 12a of the door 12. A nut 66 is shown to secure the L-shaped section 29 to the mounting bracket 28. A pair of openings 27 (denoted in FIG. 4) are provided in the shield 20 to provide access to the fastening devices 21a.

When the door 12 is closed, the protective shield 20 is operatively attached to a pair of, e.g., steel blocks 14a and 14b, which are fixedly attached to the system chassis 15, respectively, via a first latch assembly 30 and a second latch assembly 40. Each of the first 14a and the second blocks 14b are fixedly attached to the system chassis 15, e.g., using a plurality of fastening devices 31 such as screws, bolts, rivets, and the like. The first latch assembly 30 is disposed at and releasably attached to a first (hinge) end of the shield 20 and the second latch assembly 40 is disposed at and releasably attached to the second (opposite) end of the shield 20.

Referring to FIG. 3 and to FIG. 4, a first latch assembly 30 will be described. In pertinent part, the first latch assembly 30 includes a pair of, i.e., upper 25a and lower 25b, engagement pins 25 that are adapted to engage a pair of, e.g., upper 26a and lower 26b, channels 26 in a first, slotted block 14a. Preferably, each of the channels 26a and 26b includes a block portion 23 that is structured and arranged so as not to hinder the engagement pins 25a and 25b as they travel through the channels 26a and 26b as the door 12 is being closed, but to retard or otherwise minimize any further movement of the engagement pins 25a and 25b after the door is properly closed and in a locked state. The upper engagement pin 25a is fixedly attached, e.g., welded, to an upper, e.g., steel, block 22 and the lower engagement pin 25b is fixedly attached, e.g., welded, to a lower, e.g., steel, block 24, which is partially represented in FIG. 3 for the sake of clarity.

Each of the upper and lower blocks 22 and 24 is releasably attached on a first side to the underside of the shield 20, e.g., using at least one fastening device 21b, e.g. screw, bolt, rivet, and the like. As shown in FIG. 3, the second sides of the upper and lower blocks 22 and 24, which are opposite the first sides that are attached to the shield 20, are free-hanging in the plenum area. Having described a first, slotted block 14a and a first latch assembly 30, a second, latch pin block 14b and a second latch assembly 40 will be described. Referring to FIG. 5, there is shown a second, latch pin block 14b that is fixedly attached to the system chassis 15, e.g., using a plurality of fastening devices 31 such as screws, bolts, rivets, and the like. The second, latch pin block 14b includes a cylindrical latch pin 35 that is fixedly attached to a projecting portion 39 of the second, latch pin block 14b. Preferably, the latch pin 35 includes a cap or knob portion 32 that has an outer, peripheral dimension that is greater than the outer, peripheral dimension of the latch pin 35.

A sensing device 33, e.g., a proximity sensor, can be disposed on the lower surface of the second, latch pin block 14b. More particularly, the sensing device 33, e.g., a magnetic sensing device, is disposed on the lower surface of the second, latch pin block 14b at such an elevation so as to be in registration with a signal device, e.g., a magnetic field-generating device 49, (described hereinbelow with reference to FIGs. 6 to 7B) that is disposed on and integrated into the second latch assembly 40. The sensing device 33 includes a data bus 34 that is adapted to transmit data signals of the state of the door 12, e.g., open or closed and locked, from the sensing device 33 to a dedicated controller (not shown) and/or to the centrifuge controller (not shown). For example, the sensing device 33 can be structured and arranged to generate a "closed and locked" signal when the magnetic field-generating device and/or a special signal device 49 is within a pre-determined distance, e.g., 2 mm, of the sensing device 33.

Referring to FIG. 6 and to FIGs. 7A and 7B, a mounting system for the second latch assembly 40 and for the shield 20 are shown. Those skilled in the art can appreciate that there are a myriad of ways to mount a shield 20 to the inner surface 12a of the door 12; hence, the following description is illustrative and not to be construed as limiting. There are also a variety of latches manufactured that can be used.

The shield 20 can be fixedly attached, e.g., welded, to a first L-shaped mounting bracket 41 that is, in turn, securely and releasably attached, e.g., using a plurality of fastening devices 21c such as screws, nuts, rivets, and the like, to a second L-shaped mounting bracket 42. The first leg 42a of the second L-shaped mounting bracket 42 can be fixedly attached, e.g., welded, to the inner surface 12a of the door 12 and the second leg 42b can be fixedly attached, e.g., welded, to the peripheral edge of the door 12b (denoted in FIG. 7A) . The shield 20 includes a small cut-out section 54 and the second leg 41b of the first L-shaped mounting bracket 41 also includes a cut-out section 44. The cut-out sections 44 and 54 are each structured and arranged to accommodate the latch pin 35 and the knob portion 32 as the door 12 is closed.

Preferably, the second latch assembly 40 is an off-the- shelf rotary-type latch such as the R4 rotary latch or the R4- EM electronic rotary latch manufactured by Southco of Concordville, Pennsylvania. A bracket 43 of the second latch mechanism 40 can be securely and releasably attached to the second leg 41b of the first L-shaped mounting bracket 41, e.g., using a plurality of fastening devices 21d such as screws, nuts, rivets, and the like. The bracket 43 is structured and arranged to include a central portion as well as a first projection 48a and a second projection 48b that are disposed orthogonally or substantially orthogonally at opposite ends of the central portion. The second projection 48b includes a signaling device 49 attached thereto. The central portion of the bracket 43 further includes nesting latch jaws 46 and 47, which are structured and arranged to accommodate a latch pin 35.

Referring to FIGs. 7A, 7B, and 8, there is shown a spring- loaded, latch release mechanism 50. A latch lever 19 of the latch release mechanism 50 can be made from hard rubber or plastic, e.g., a PC/ABS blend plastic. The latch release mechanism 50 is structured and arranged to provide sufficient mechanical advantage, to cause the locking latch 45 to rotate much like the door locking system of an automobile. When the latch lever 19 is depressed, resulting tension on a cable or bar 53 causes the locking latch 45 to rotate outwards to an open position by which the latch pin 35 has unhindered access to the cut-out section 54 in the shield 20, the cut-out section 44 of the second leg 41b of the first mounting bracket 41, and the nesting latch jaws 46 and 47.

Although the invention has been described assuming that the shield portion 20 is attached to the door 12, those of ordinary skill in the art can appreciate that the shield 20 could be attached directly to the sub-system frame 15. Furthermore, although the latch assemblies 30, 40, block assemblies 14a, 14b, and shield portion 20 have been described as being releasably attached to the door 12 and/or the sub^¬ system frame 15, alternatively, the assemblies could be fixedly attached or integrated into the door 12 and/or sub-system frame 15.

Although preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications may be made in the invention and that the appended claims are intended to cover all such modifications which fall within the spirit and scope of the invention. APPENDIX A

1. Centrifuge Energy

Given Data:

Rotor mass with four (4) loaded buckets (m_T) = 12.16 kg

Loaded Rotor Radius (r_R) = 0.132 m

Velocity of Spinning Rotor (ω_κ) = 471 rad/sec

Mass Moment of Inertia of spinning rotor (I_R) = m_T * (r_R)² = 12.16 kg * (0.132 m) ² = 0.212 kg-m²

Energy of Spinning Rotor (E_R) = 0.5 * I_R * (ω_κ)² =

0.5 * 0.212 kg-m^' 2 (471 rad/sec)² = 23.5 kJ

This is the stored energy that is instantly released during the failure of the centrifuge.

Based on video evidence of a centrifuge failure, a catastrophic failure event lasts for about 1050 ms, which includes about 300 ms for the rotor displacement followed by about 750 ms for entire unit displacement and will cause a free-standing, 170 kg (375 pound) Hettich Centrifuge unit to rotate approximately 270° .

2. Crash Event Forces and Displacements

Given Data: Crash Event Angular Displacement of Centrifuge (cp_c) = 270° = 4.7 rad

Duration of Centrifuge unit displacement (t_c) = 0.75 sec

Centrifuge mass (m_c) = 170 kg

Centrifuge mass with friction factor of 60% from rubber feet on floor (m_cf) = 272 kg

Outer radius of centrifuge relative to spinning center of rotor (r_c) = 0.492 m

Angular Acceleration of Centrifuge ( _c) = (2 * cp_c)/(t_c)² assuming a triangular kinematic profile in which one-half of the total time and distance occurs during acceleration and one-half of the total time and distance occurs during deceleration, cp_c = 1/2 * 4.7 rads = 2.35 rads and t_c = 1/2 * (0.75 sec) = 0.375 sec. Therefore, c = (2*2.35 rads)/(0.375 sec)² = 33.4 rad/sec²

It is understood that a catastrophic crash event may not react as expected in the calculations, i.e., eccentric rotation or exact displacement of rubber mounting feet, however, the prototype and final design will allow enough safety factor to compensate for these differences.

Mass Moment of Inertia of spinning Centrifuge unit (I_c) = m_cf (r_c)²

272 kg * (0.492 m) ² = 65.8 kg-m²

Torque induced from crash event (T_c) = I_c * _c = 65.8 kg-πΓ * 33.4 rad/sec' = 2,199.1 N-m

3.1. Mounting Feet Analysis

The rubber mounting feet are the first items affected in the load path of the crash event. Accordingly, the following calculations analyze the integrity of the rubber feet in the event of this failure.

Given Data: Maximum Shear Force of each rubber mounting foot [4 total] (F_f) = 370 N

Rubber mounting foot spring rate in shear (k_f) = 47 N/mm Radius of centrifuge feet relative to spinning center of rotor (r_f) = 0.348 m

Shear Force on rubber mounting feet (F_Tf) = T_c/r_f = 2199.1 N-m /0.348 m = 6,319.3 N

Maximum Shear Force allowed on four (4) rubber feet (F_fM) = F_f * 4 = 370 N * 4 = 1480 N < F_Tf

Since F_Tf > F_fM, the rubber mounting feet are at risk of failing . Linear deflection of each rubber mounting feet (S_f) = (F_Tf/4)/ k_f

= (6319.3 N /4)/47 N/mm = 33.6 mm

Assuming the feet do not fail under shear stress:

Resulting Angular deflection of rubber mounting feet (cp_f) = sin^-1 (2S_f/2r_f)

= sin^-1 [(2 * 33.6 mm)/ (2 * 348 mm) ] = 5.5°

Linear deflection of Centrifuge due to compliant rubber feet (S_c) = 2 * r_c * sin(f_f/2)

= 2 * 492 mm * sin(5.5⁰/ 2) = 47.2 mm

The linear deflection (Sc) shows that the centrifuge may displace sufficiently to impact surrounding parts. If the centrifuge were to strike an unbraced door during this event, it could force the door open and possibly cause injury to an operator.

3.2. Forces for Design

Since the rubber feet can fail during a crash event, a shield will need to be designed that is strong enough to handle the Shear Force (F_Tf) and Total Force (F_cT) of the crash event. The Shear and Total Forces are tangential forces induced by the spin reaction of the centrifuge. Calculations from above: T_c = 2199.1 N-m r_c = 0.492 m F_Tf = 6319.3 N Total Force if rubber feet are removed from load path (F_cT) = T_c / r_c =

2199.1 N-m / 0.492 m = 4469.7 N < F_Tf Since F_cT < F_Tf, F_Tf controls design.

4. Locking Pin and Pin Receptacle Design

The impact force is assumed to be distributed equally to all locking pins.

Locking Pin Given Data:

Locking Pin Material = 304 Stainless Steel

304 SST Shear Yield Stress (o_ssM) = 150 MPa

Locking Pin Diameter (d_P) = 0.00953 m

From above calculations, F_Tf = 6319.3 N Shear area of Locking Pin (a_Sp) = (n * d_P ²) / 4 =

(n * (0.00953 m)²) / 4 = 7.13 E^'5 m²

Maximum stress on single pin (o_PM) = (F_Tf / 4)/ o_s = (6319.3 N / 4) / 7.13 E^~5 m² = 22.2 MPa

For a safety factor (Fs) = 4

Maximum stress on single pin (o_PM4x) = o_PM * FS = 22.2 MPa * 4 = 88.8 MPa < 150 MPa

In short, with a factor of safety of 4, the locking pin only shows 60% of the maximum yield stress.

Pin Receptacle Given Data:

Pin Receptacle Material = 6061-T6 aluminum

6061-T6 aluminum Shear Yield Stress (osAM) = 140 MPa

Shear area of Pin Receptacle (a_Sr) = 3.22 E^~4 m² From above: F_Tf = 6319.3 N

Maximum Receptacle Stress induced by pin (o_rM) = (F_Tf /4)/ a_Sr =

(6319.3 N /4)/3.22 E^~4 m² = 4.9 MPa

Maximum shear stress w/ (o_rM4_X) = o_rM * FS =

4.9 MPa * 4 = 19.6 MPa < 140 MPa Hence, the pin receptacle shows less than 14% of the maximum yield stress, thereby proving to be strong enough for the application .

5. Final Shield Design Final shield design includes a latching mechanism (similar to an automobile door) rather than the four locking pins from the above calculations. It was also important to keep equal structural integrity and safety as the prototype (as per DHF- 001848 and IEC/EN 61010-2-020) . New design will keep two (2) fixed pins and pin receptacles on a hinge side of the door and a single latch and latch pin on the opposing side of the door.

Approximate displacement of constrained Hettich centrifuge

Actual linear deflection of rubber foot (S_CA) = 2 * r_c * sin(cp_FA/2) =

2 * 492 mm * sin(6⁰/ 2) = 51.0 mm Actual Shear Force on single rubber mounting foot (F_TfA) = S_CA*k_f

51.0 mm * 47 N/mm = 2397.0 N > F_f Hence, because F_TfA > F_f, the rubber mounting feet are at risk of failing and it is important to design a shield that protects the operator in the event of a failure of the mounting feet during a crash event. Actual Torque induced by crash event (T_cA) = F_TfA * r_f =

2397.0 N * 0.348 m = 834.0 N-m

Actual impact force at corner of Hettich (F_cTA) = T_cA/r_c = 834.0 N-m / 0.492 m = 1695.1 N < F

Latch Pin Given Data:

Latch Pin Material = 1018 CRS

1018 CRS Shear Yield Stress (O_S10I_8M) = 145 MPa

Latch Pin Diameter (d_Lp) = 0.0127 m

F_Tf = 6319.3 N

Shear area of Latch Pin (a_Si_P) = (n * d_Lp ²) / 4 = (n * (0.0127 m)²) / 4 = 1.27 E^'4 m²

Maximum stress of Latch Pin (θι_ρΜ) = (F_Tf / 3)/ a_Si_P = (6319.3 N / 3) / 1.27 E^~4 m² = 16.6 MPa

For a safety factor (f_s) of 4

Maximum stress on single pin w/ f_s (oi_pM4_X) = Oi_pM * f_s = 16.6 MPa * 4 = 66.4 MPa < 145 MPa

The Latch Pin is only showing 46% of the maximum yield stress, thereby proving to be strong enough for the application. Since the pins perform at 46% of their maximum shear stress, the design does not compromise the system safety.

Latch Given Data:

Load strength of Southco R4 latch (F_x) = 15120 N

F_tF = 6319.3 N Nominal Safety Factor of R4 Latch (f_Snom) = Fi / (F_Tf / 3) 15120 N / (6319.3 N / 3) = 7.2

Nominal Safety Factor of R4 Latch with 4x load (fs₄x) ^— I (FTf * 4)

= 15120 N / ((6319.3 N / 3) * 4) = 1.8

With a 4x load factor, the R4 Latch is only at 56.0% of the maximum permissible loading, thereby proving to be strong enough for the application.

New Pin Receptacle Given Data:

Pin Receptacle Material = 1018 CRS

1018 CRS Shear Yield Stress (o_sl0i_8M) = 145 MPa

Shear area of Pin Receptacle (a_Sr) = 2.30 E^~4 m²

F_Tf = 6319.3 N

Maximum Receptacle Stress induced by pin (o_rM) = (F_Tf / 3)/ a_Sr =

(6319.3 N / 3) / 2.30 E^~4 m² = 9.2 MPa

Maximum shear stress w/f_s (o_rM4X) = o_rM * f_s = 9.2 MPa * 4 = 37.0 MPa < 145 MPa

With a 4x load factor, the pin receptacle is only about 25% of the maximum yield stress, thereby proving to be strong enough for the application. Assuming an R4 Latch release lever force and Operator actuation force

R4 Latch Given Data:

Spring Rate of R4 Latch Release Arm (k_R4) = 0.116 N-m

Radial distance or R4 Latch Release Arm (r_R4) = 0.0246 m

R4 Latch Initial Release Force (F_R4) = k_R4 / r_R4 =

0.116 N-m / 0.0246 m = 4.72 N

The Latch Lever has a mechanical advantage of 8:1, so the operator actuation force is:

Latch Lever Mechanical Advantage (m_aLa) = 8

Operator Actuation Force (F_op) = F_R4 / m_aLa =

4.72 N / 8 = 0.59 N

Claims

What we claim is:

1. A protective, safety device for use with a centrifuge that is at least one of constrained and retained in a constraining/retaining system, the system having a sub-system frame having a first, slotted block that is releasably attached to the sub-system frame and a second block, having a latch pin, that is releasably attached to the sub-system frame and a door that is rotatably attached to the sub-system frame, the protective, safety device comprising:

a first latch assembly that is releasably attached to the door at a first end, proximate the first, slotted block;

a second latch assembly that is releasably attached to the door at a second end, proximate the second block;

a shield portion that is releasably attached to the door and the first latch assembly at the first end and releasably attached to the door and second latch assembly at the second end; and

a latch release assembly that is disposed on the door and operatively coupled to the second latch assembly, the release assembly structured and arranged to open or to close and lock the second latch assembly about the second block.

2. The device as recited in claim 1, wherein the first latch assembly includes a plurality of engagement pins that is structured and arranged to interface with corresponding channel portions in the first, slotted block, to fully engage the corresponding channel portions when the door is in a closed and locked state.

3. The device as recited in claim 1, wherein the second latch assembly includes a signal device that is adapted to interface with a sensing device integrated in the second block.

4. The device as recited in claim 1, wherein the second latch assembly includes a latch locking member that is adapted to engage the latch pin of the second block, to lock the door.

5. The device as recited in claim 1, wherein the second latch assembly includes a plurality of engagement pins that is structured and arranged to interface with corresponding channel portions in the second block, to fully engage the corresponding channel portions when the door is in a closed and locked state.

6. A centrifuge assembly comprising:

a constraining/retaining system, the system having a sub- system frame and a door that is rotatably attached to the sub^¬ system frame;

a centrifuge that is at least one of constrained and retained in the constraining/retaining system; and

a protective, safety device further comprising:

a first, slotted block that is releasably attached to the sub-system frame;

a second block that is releasably attached to the sub-system frame;

a first latch assembly that is releasably attached to the door at a first end, proximate the first, slotted block ;

a second latch assembly that is releasably attached to the door at a second end, proximate the second block; a shield portion that is releasably attached to the door and the first latch assembly at the first end and releasably attached to the door and second latch assembly at the second end; and

a latch release assembly that is disposed on the door and operatively coupled to the second latch assembly, the latch release assembly structured and arranged to open or to close and lock the second latch assembly about the second block.

7. The assembly as recited in claim 6, wherein the first latch assembly includes a plurality of engagement pins that is structured and arranged to interface with corresponding channel portions in the first, slotted block, to fully engage the corresponding channel portions when the door is in a closed and locked state.

8. The assembly as recited in claim 6, wherein the second latch assembly includes a signal device that is adapted to interface with a sensing device integrated in the second block.

9. The assembly as recited in claim 6, wherein the second latch assembly includes a latch locking member that is adapted to engage the latch pin of the second block, to lock the door.

10. The assembly as recited in claim 6, wherein the second latch assembly includes a plurality of engagement pins that is structured and arranged to interface with corresponding channel portions in the second block, to fully engage the corresponding channel portions when the door is in a closed can locked state.

11. An improvement to a centrifuge assembly having a centrifuge that is at least one of constrained and retained in a constraining/retaining system, the system having a sub-system frame and a door that is rotatably attached to the sub-system frame, the improvement comprising:

a first, slotted block that is releasably attached to the sub-system frame;

a second block that is releasably attached to the sub^¬ system frame;

12. The improvement as recited in claim 11, wherein the first latch assembly includes a plurality of engagement pins that is structured and arranged to interface with corresponding channel portions in the first, slotted block, to fully engage the corresponding channel portions when the door is in a closed and locked state.

13. The improvement as recited in claim 11, wherein the second latch assembly includes a signal device that is adapted to interface with a sensing device integrated with the second block .

14. The improvement as recited in claim 11, wherein the second block includes a latch pin and the second block includes a latch locking device that is structured and arranged to retain the latch pin so that any load applied to the shield portion is transferred to the sub-system frame via the second block after the door is closed.

15. The improvement as recited in claim 11, wherein the first, slotted block includes a plurality of channel portions that are structured and arranged to retain corresponding engagement pins in the first latch assembly so that any load applied to the shield portion is transferred to the sub-system frame via the first slotted block after the door is closed.

16. The improvement as recited in claim 11, wherein the second block includes a data bus that is electrically coupled to a controller in the centrifuge.

17. The improvement as recited in claim 11, wherein the second block is slotted and includes a plurality of channel portions that is structured and arranged to retain corresponding engagement pins in the second latch assembly so that any load applied to the shield portion is transferred to the sub-system frame via the second, slotted block after the door is closed.