System and method for testing damping material

Abstract

Systems and methods are disclosed for testing the torque response of damping materials. The system and method include a rotatable arrangement of nested components with damping material disposed therebetween. In other words, a first component is rotatably arranged with a second component for rotation of the first component for a predetermined rotation angle and / or time and / or at a predetermined speed for measurement of a torque response, or resistive torque, during position movement of the first component.

Description

SYSTEM AND METHOD FOR TESTING DAMPING MATERIALFIELD OF THE DISCLOSURE

[0001] The present disclosure relates to methods of testing damping materials and systems for conducting such methods. In particular, the present disclosure relates to systems and methods for testing the torque response of damping materials.BACKGROUND OF THE DISCLOSURE

[0002] Damping materials may be used to mitigate, slow, or eliminate vibration, noise, and / or movement of components in a system or environment during operation. Damping materials may include a wide range of compositions and their phases and may be used in a widely diverse range of environments. Generally, damping materials can be second- phase thixotropic additives in oils (oils being Newtonian). In some damping materials, PDMS (polydimethysiloxane) medical grade silicone oil is used. When thixotropic additives are added to oil, the mix become non-Newtonian, which means the viscosity can be affected by shear rate. The effectiveness of the damping material used for any particular environment or system is unique to the properties of the damping material and the system in which it is used; as such, the testing methods and systems for damping materials must be accurate and precise for the unique intended purpose of the damping material.SUMMARY OF THE DISCLOSURE

[0003] The present disclosure relates to systems and methods for testing the torque response of damping materials. The system and method include a rotatable arrangement of nested components with damping material disposed therebetween. In other words, a first component is rotatably arranged with a second component for rotation of the first component for a predetermined rotation angle and / or time and / or at a predetermined speed for measurement of a torque response, or resistive torque, during position movement of the first component.

[0004] In a first aspect of the disclosure a method for testing mechanical timing of a mechanical device is presented, the method including detecting a first position of a first component in nested arrangement with a second component, the first component communicatively coupled with a load cell, and including a substance positioned between thefirst component and the second component; triggering rotation of the first component relative to the second component; detecting angular position movement of the first component during rotation; detecting resistive torque during position movement of the first component with the load cell; and comparing the detected resistive torque with the detected angular position movement.

[0005] In the second aspect of the disclosure, a system for testing mechanical timing of a mechanical device is presented, the system including a first component and a second component rotatably arranged; a rotational member coupled to the first component; a load cell communicatively coupled to the first component; and a substance disposed between the first component and the second component.

[0006] In various aspects of the disclosure, triggering rotation of the first component relative to the second component may include releasing a loaded torsional spring coupled to the first component.

[0007] In various aspects of the disclosure, triggering rotation of the first component relative to the second component may include operating an actuator configured to rotate the first component.

[0008] In various aspects of the disclosure, rotation of the first component relative to the second component may be speed-controlled at a predetermined speed.

[0009] In various aspects of the disclosure, angular position movement of the first component may include a predetermined degree of angular movement.

[0010] In various aspects of the disclosure, the method may further include arranging the first component and the second component in a stacked arrangement on the load cell.

[0011] In various aspects of the disclosure, the first component and the second component may be formed of plastic.

[0012] In various aspects of the disclosure, the method may further include removably fixing the second component in place to prevent rotation of the second component.

[0013] In various aspects of the disclosure, the first component and the second component may be arranged in a stacked arrangement on the load cell.

[0014] In various aspects of the disclosure, the rotational member may be an actuator arm configured to rotate the first component relative to the second component. A thirdcomponent may be coupled to the first component and configured to interface with the actuator arm to facilitate rotation of the first component. The third component may be coupled to the first component with a tab-in-groove arrangement. The third component may receive at least a portion of the actuator arm.

[0015] In various aspects of the disclosure, the rotation member may be a torsional spring coupled to the first component.

[0016] In various aspects of the disclosure, the first component and the second component may be in a nested arrangement.

[0017] In various aspects of the disclosure, the system may further include a pin configured to be received by the second component to prevent rotation of the second component.

[0018] In various aspects of the disclosure, the substance may be a damping material.

[0019] Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The foregoing aspects and many additional features of the present invention and accompanying methods will become more readily appreciated and become better understood by reference to the following detailed description when taken in conjunction with the accompanying figures. The detailed description of the drawings particularly refers to the accompanying figures in which:

[0011] FIG. 1 illustrates a medication delivery device using a mechanical timer including damping material for timed operation including the delivery of medication;

[0012] FIG. 2 illustrates a cross-sectional view of the medication delivery device of FIG. 1;

[0013] FIG. 3A is a first perspective view of a first component of the mechanical timer of FIG. 1;

[0014] FIG. 3B is a first plan view of the first component of FIG. 3A;

[0015] FIG. 3C is a second perspective view of the first component of FIG. 3A;

[0016] FIG. 3D is a second plan view of the first component of FIG. 3A;

[0017] FIG. 3E is a cross-sectional view of the first component of FIG. 3A;

[0018] FIG. 4A is a perspective view of another component of the mechanical timer of FIG. 1;

[0019] FIG. 4B is a top view of the component of FIG. 4A;

[0020] FIG. 5A is a plan view of an assembly including the first component of FIG.3 A and the component of FIG. 4A;

[0021] FIG. 5B is a perspective view of the assembly of FIG. 5A;

[0022] FIG. 6A illustrates a perspective view of yet another component used for the mechanical timer of the medication delivery device of FIG. 1;

[0023] FIG. 6B is a side view of the component of FIG. 6A;

[0024] FIG. 7A is a partially exploded view of the mechanical timer of the medication delivery device of FIG. 1;

[0025] FIG. 7B is a cross-sectional view of the mechanical timer of the medication delivery device of FIG. 7A;

[0026] FIG. 7C is a close-up view of the mechanical timer of the medication delivery device of FIG. 7A;

[0027] FIG. 8 illustrates a fixture for testing a damping material for use with a mechanical timer of a medication delivery device;

[0028] FIG. 9 illustrates a load cell and base of the fixture of FIG. 8;

[0029] FIG. 10 illustrates the fixture of FIG. 8 including a first component, a second component, and a third component in a stacked configuration for testing the damping material;

[0030] FIG. 11 is a close-up view of the first component, the second component, and the third component in the stacked configuration;

[0031] FIG. 12A illustrates the placement of the damping material within the second component;

[0032] FIG. 12B illustrates a stacked configuration of the first component and the second component;

[0033] FIG. 13 illustrates a perspective view of the stacked configuration of the first component, the second component, and the third component;

[0034] FIG. 14 illustrates a method for testing a torque response of damping material;

[0035] FIG. 15 illustrates an exemplary testing result following use of the fixture ofFIG. 8; and

[0036] FIG. 16 illustrates comparative testing results of differing damping materials following use of the fixture of FIG. 8.

[0037] Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of various features and components according to the present disclosure, the drawings are not necessarily to scale, and certain figures may be exaggerated in order to better illustrate and explain the present disclosure.DETAILED DESCRIPTION OF THE DRAWINGS

[0038] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, which are described herein. The embodiments disclosed herein are not intended to be exhaustive or to limit the invention to the precise form disclosed. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings.Therefore, no limitation of the scope of the claimed invention is thereby intended. The present invention includes any alterations and further modifications of the illustrated devices and described methods and further applications of principles in the invention which would normally occur to one skilled in the art to which the invention relates.

[0039] The terms “couples”, “coupled”, “coupler” and variations thereof are used to include both arrangements wherein the two or more components are in direct physical contact and arrangements wherein the two or more components are not in direct contact with each other (e.g., the components are “coupled” via at least a third component), but yet still cooperate or interact with each other.

[0040] In some instances throughout this disclosure and in the claims, numeric terminology, such as first, second, third, fourth, etc., is used in reference to various components of features. Such use is not intended to denote an ordering of the components orfeatures. Rather, numeric terminology is used to assist the reader in identifying the components or features being referenced and should not be narrowly interpreted as providing a specific order of components or features.

[0041] Damping gels can be used in many applications for an expected beneficial performance. The terms “damping gel” and “damping material” can be used interchangeably. In one application, a medical device’s performance may be characterized using the rheological behavior of the damping gel, in that, the viscosity response to shear is measured using rheology-based equipment resulting in a series of plots after exposure of the damping gel to different environmental conditions such as temperature, time, and shelf life. For example, a damping gel can be used in a medical device to modulate (damp) mechanicaltiming of a moving component, such as assisting injection needle articulation post- injection. Gel dispensing in manufacturing is also a consideration. Manufacturers of damping gels arrive at a satisfactory thixotropic formulation by varying the particle-systems or modifying processing of the formulation for gelation and mitigation of oil migration / particle agglomeration. The formulation is then validated for a time response for a predetermined device operation, such as needle articulation (e.g., needle retraction), using medical device testing. While early formulation testing (rheology testing) is less expensive - and the results obtained are limited in their device-specific functional translation value -final device testing using the gel is expensive and time consuming. The inventors have found a novel method and system that can bridge the gap between early formulation testing and final device testing that take into account the relative motion and flex of medical device components. This could be helpful when evaluating multiple damping gels at once to more quickly down select which damping gels to conduct final device testing which can be costly. Also, as regulations of certain compounds change for a commercial device, the need to quickly evaluate, down select, and test new compounds of damping gels is desirable to avoid delays to the distribution of the commercial device.

[0042] Predictive mechanical timing property of a damping gel is a result of the complex interactions within the gap from relative movement between the first component and the second component - the interacting parameters being tangential velocity, radius, wetted surface area, viscosity, and the gap between components. The gap can allow for relative flex or motion between the components. Stress decay testing provided a rotational response (degrees) for a given time (seconds) using moving components made of steel or rigid materials. The rotational response for a fixed time (design-intent mechanical time, such as,for example, 1.5 seconds) is used as a benchmark, and this test was considered the most sensitive to the flow conditions within the medical device. The limitation of the stress decay testing method may not capture the flex attribute (relative motion of the device components). Furthermore, it may limit the inclusion of damping gels spanning a greater range of viscosities so that the true limits of the acceptable rheological response may be identified. Without device-design context, a damping gel specification developed using stress decay test may be less relevant, especially when not including the flex attribute of the device. The term “flex” used herein is defined as the uneven deflection of plastic contact components due to the stress they experience from relative motion, which can include even and uneven distortion of the size of the components from shrinkage or deflection of the components.

[0043] The novel method described herein a method and system for obtaining a torque response of a device subassembly containing a damping gel, which can provide representative controls to bridge the gap between early formulation stress decay testing and final medical device performance testing to compare to design specification and provide data for clinical trials. There are several advantages of this approach. The method and system can provide evaluative information that incorporate the flex of a component of the device. The method and system can be modified as a universal test to obtain a torque response for a given rotation time. The response can be used to evaluate-and-engineer a response that is representative of device components’ relative movement and flexing. The method and system can be used to more quickly develop, test, and down select new damping gel formulations. The method and system described herein can obtain a response from the damping gels by speed-controlled rotation as input. Controlled rotation as a torque input to a device subassembly of moving components results in a torque-response output that can provide insight into the combined effect of the gel rheology behavior and flex attributes of the device and its components.Exemplary Medication Delivery Device

[0044] The system and method described herein may be beneficial for a medication delivery device having a first component moving relative to a second component, where a damping gel is disposed between the components. One of the first component and the second component may be stationary during device operation, while the other of the components may be moving. Alternatively, both the components may be moving during the deviceoperation. One or both the first component and the second component may be made of a material having capable of a flex. Referring initially to FIGS. 1-2, a medication delivery device 100, e.g., an automatic injection device, is illustrated. Medication delivery device 100 may include a mechanical timer mechanism, so that when medication delivery device 100 is operated, a needle 102 extends beyond a distal end 104 of a housing 106 of the medication delivery device so as to inject a user with a medication contained within the medication delivery device. The mechanical timer mechanism may facilitate the automatic injection of the medication through needle 102 without further action from the user, including retraction of needle 102 into housing 106 once delivery of the medication is complete.

[0045] Referring additionally to FIGS. 3A-7C, medication delivery device 100 may include a mechanical timer 108 including a follower, or first component 110; a collar, or second component 112; and a shuttle portion, or third component 114. Mechanical timer 108 facilitates timing of the injection and retraction of needle 102 for automatic operation of medication delivery device 100 and accurate dosage delivery of the corresponding medication.

[0046] FIGS. 3A-3E illustrate first component 110, or a follower, of mechanical timer 108. First component 110 includes a sidewall 117 defining an opening 118 for receiving third component 114 as discussed further herein. Ridges 120, 122 located at a proximal portion 124 of first component 110 are sized and shaped to interact with third component 114 as discussed further herein for rotation of first component 110 and operation of mechanical timer 108. Sidewall opening 126, along with opening 118, facilitate axial movement of third component 114 relative to first component 110. Sidewall opening 126 may taper to a slot 128 configured to closely receive a projection of a biasing member, illustratively torsional spring 132 (FIG. 7A-7B). An inner surface 134 of sidewall 117 defines an annular ring 136 with a lip 138 for positioning of torsional spring 132.

[0047] A distal portion 140 of first component 110 extends from proximal portion 124. Distal portion 140 defines a smaller diameter than a diameter of proximal portion 124, and distal portion 140 is configured to be received by second component 112 as discussed further herein. A plurality of slots 142 defined within distal portion 140 of sidewall 117 define fins 144, which interact with damping material 116 (FIG. 2) to create delay times during operation of medication delivery device 100. Slots 142 may vary in size and shape for variation of delay times. An arm 146 with upwardly extending protrusion 148 is configuredto lock first component 110 relative to third component 114 when coupled to limit rotation of first component 110 relative to third component 114. Upwardly extending protrusion 148 may include a first surface portion 166 which is generally longitudinal to an axis of first component 110 and a second surface portion 168 which forms a point with first surface portion 166 and curves away from first surface portion 166.

[0048] Now referring to FIGS 4A-4B, third component 114 includes a distal projection 150 including tabs 152, 154 radially projecting therefrom. Tabs 152, 154 latch or hook ridges 120, 122 of first component 110 as described above when third component 114 is coupled to first component 110. In other words, tabs 152, 154 may form a tab-in-groove arrangement with ridges 120, 122. Opening 156 leading to pocket 158 of tab 152 is configured to receive a second projection of torsional spring 132.

[0049] Referring to FIGS. 5A-5B in addition to FIGS. 3A-4B, an assembled configuration of first component 110 and third component 114 is illustrated. Upwardly extending projection 148 of arm 146 of first component 110 may be engaged with a protrusion 162 positioned on an exterior surface 164 of distal projection 150 of third component 114. First surface portion 166 of arm 146 of first component 110 engages with protrusion 162 of third component 114 in a first, locked configuration during operation (i.e., when movement of first component 110 relative to third component 114 is limited); second surface portion 168 may slidingly engaged with an undercut region 170 of third component 114 positioned adjacent protrusion 162 in a second, unlocked configuration during operation (i.e., when movement of first component 110 relative to third component 114 is permitted), while first surface portion 166 is disengaged from protrusion 162.

[0050] Second component 112 is illustrated in FIGS. 6A-6B. Second component 112 is annular in shape to define an opening 172 sized and shaped to receive a syringe barrel of the medication delivery device 100 and includes an inner wall 174 and an outer wall 176 forming a gap 178 therebetween so that a cross-section of second component 112 is generally U-shaped (FIGS. 7B-7C). Referring additionally to FIGS. 7A-7C, at least a portion of distal portion 140 of first component 110 is received by gap 178 of second component 112 so that first component 110 and second component 112 form a nested configuration. A substance, for example, damping material 116, may be disposed in gap 178 formed by second component 112 so that the substance is generally positioned between first component 110 and second component 112.

[0051] In embodiments including damping material, the amount and type of damping material 116 used may depend on the properties of a particular damping material or compound and / or the desired timing effect for operation of medication delivery device 100. For example, referring again to FIGS. 3A-6B, damping material 116 (FIG. 2) may fill or partially fill gap 178 of second component 112. Fins 144 of first component 110 are configured to be received by gap 178 of second component 112 so that damping material 116 may be both radially inward and outward of fins 144 and / or between fins 144 so that damping material 116 causes a damping or delay effect as fins 144 rotate relative to second component 112 as described further herein.

[0052] During operation of the medication delivery device, upwardly extending protrusion 332 of arm 330 of first component 110 is disengaged from protrusion 162 of third component 114 upon deployment of needle 102. When upwardly extending protrusion 332 of arm 330 is disengaged from protrusion 162 of third component 114, first component 110 and third component 114 are in the unlocked configuration in which first component is permitted to rotate relative to third component 114. Torsional spring 132 biases first component 110 to rotate against the damping effect of damping material 116 until tabs 152 154 of third component 114 are cleared from ridges 120, 122 of first component 110, at which point first component 110 and third component 114 and torsional spring 132 is permitted to decompress, retracting needle 102. When spring 132 decompress, the spring torque decays as it unwinds. Additional information regarding medication delivery device 100 and its components may be found in U.S. Publication No. 2021 / 0275745 to Atterbury, et. al, entitled AUTOMATIC INJECTION SYSTEM and published September 9, 2021, the entirety of which is incorporated by reference herein.Testing Assembly and Method for Damping Material

[0053] Referring again to FIGS. 7A-7C, testing of various potential damping materials may include at least some of the components of mechanical timer 108 as described above, including first component 110, second component 112, and third component 114. Combined, these components are referred to herein as a gel containment assembly 180. FIGS. 7A-7C provide various views of gel containment assemblyl80 and the components thereof for use in testing. For example, FIG. 7A provides an isometric view, with second component 112 being removed from first component 110 and third component 114.

[0054] FIG. 7B illustrates a cross-sectional area of the gel containment assembly 180, showing the clearance between distal portion 140, or a plunger 182, of first component 110 and a collective inner surface 184 of inner and outer walls 174, 176, respectively, defining gap 178. FIG. 7C illustrates a close-up cross-sectional view of the interface between first component 110 and second component 112, including gap 178 where damping material 116 (FIG. 12A) is placed. Gap 178 defines a plunge depth corresponding with plunger 182 of first component 110. Collective inner surface 184 may define a surface roughness to facilitate resistive torque of damping material 116, measured as a function of the rotation angle of a testing fixture as described further herein, allowing for the 3D transient behavior of the gel to be measured.

[0055] In some embodiments, the rotation angle and / or the time to reach the rotation angle is predetermined and variable as desired, with responses to such variable changes assessed. In some embodiments, gel containment assembly 180 is a fixed flex container, providing inherent flow fields and deformation rates. Such flow fields and deformations rates facilitate the ability to obtain resistive torque responses for a range of damping materials having varying viscosity. Use of the gel containment assembly 180 and / or the testing fixture as described further herein may facilitate assessment of the 3D transient response of one or more of the variables due to the provided non-homogenous flow fields, deformations rates, and plastic flex, or the combined relative motion of the plastic components. In some embodiments, these variables may be taken as a unified parameter to be evaluated as a single design response.

[0056] Now referring to FIGS. 8-9, testing fixture 200 is illustrated. As shown in FIG. 8, testing fixture 200 includes a lower placement site 202 for positioning of gel containment assembly 180 (FIGS. 7A-7C) and an upper cylindrical protrusion 204 including a rotational member, such as an actuator arm 206, configured to interface with third component 114 of gel testing assembly 180 for rotation of third component 114 and first component 110 relative to second component 112. In other words, actuator arm 206 is configured to couple to first component 110 for rotation of first component 110 relative to second component 112 as described further herein. In some embodiments, upper cylindrical protrusion 204 has an adjustable height, which may be adjusted, for example, using a mechanical lever, a button, a detent mechanism, or other adjustment mechanisms known in the art.

[0057] FIG. 9 illustrates lower placement site 202, including a first positioning protrusion 208 having a radius generally less than a radius of opening 172 (FIG. 6B) ofsecond component 112 so that first positioning protrusion 208 is configured to be received by opening 172 of second component 112. Lower placement site 202 may include a second positioning protrusion 210 configured to interface with a positioning channel 212 on an outer surface 214 of outer wall 176 of second component 112 (FIG. 11) as described further herein, so that first positioning protrusion 208 and second positioning protrusion 210 are spaced apart in a manner that facilitates placement of second component 112 partially therebetween. Lower placement site 202 may include a load cell 216 integrated therein, e.g., lower placement site 202 may be load cell 216. In other embodiments, load cell 216 may be a wholly or partially separate component which is otherwise communicatively coupled to testing fixture 200 for operation of testing fixture 200 and for carrying out of the testing methods described further herein.

[0058] Now referring to FIGS. 10-11, placement of gel containment assembly 180 upon lower placement site 202 is illustrated. As shown, and as described further above, first positioning protrusion 208 (FIG. 9) is received within second component 112 so that first positioning protrusion 208 is not visible from a side view perspective. Second positioning protrusion 210 is received within positioning channel 212 of second component 112 to facilitate proper positioning of second component 112 and gel containment assembly 180, as well as to mitigate or prevent movement of second component 112 relative to lower placement site 202 during testing operations of testing fixture 200. Third component 114 may also include a channel 115 for receiving a portion of actuator arm 206 for rotation of third component 114 as described further herein.

[0059] Referring additionally to FIGS. 12-13, preparation of testing fixture 200 and gel containment assembly 180 for testing is illustrated. As shown in FIG. 12A, damping material 116 is disposed within gap 178 of second component 112. The amount, type, and / or distribution of damping material 116 within gap 178 may vary depending on the particulars of the desired test and / or the parameters of said test. Second component 112 and first component 110 may then be coupled as described above, i.e., with gap 178 of second component 112 receiving plunger 182 or distal portion 140 of first component 110, as shown in FIG. 12B. Second component 112 may then be positioned on lower placement site 202 so that first positioning protrusion 208 (FIG. 9) is received within opening 172 of second component 112 and second positioning protrusion 210 is received within positioning channel 212 of second component 112.

[0060] Referring now to FIG. 14, a method 300 for testing damping gel is illustrated. First, as described above in relation to FIG. 12A, damping material is distributed within the gap defined by the second component as illustrated at box 302 of method 300. The first component and the second component are then coupled in a stacked and / or nested configuration at box 304 of method 300 so that a portion of the first component is received by the second component. At box 306, the first component is rotated relative to the second component with the actuator arm of the testing fixture, either directly or via the third component.

[0061] For example, in some embodiments, such as the embodiments illustrated in FIGS. 7A-13, the third component is coupled to the first component in a stacked and / or nested configuration as described above to facilitate rotation of the first component. The actuator arm may interface with the third component to rotate the third component and, thereby, the first component. For example, in some embodiments, the third component may receive a portion of the actuator arm in a channel as described above to facilitate rotation of the third component. In some embodiments, the first component is rotated directly without the third component. In some embodiments, the actuator arm of the testing fixture replaces function of the torsional spring as described above in relation to medication delivery device 100, and actuator arm manipulates the first component and / or the third component in a manner similar to that described above during operation of medication delivery device 100. In other embodiments, the actuator arm of the testing fixture cooperates with an included torsional spring, included and configured to operate with the first component and the third component as described above in relation to medication delivery device 100, during execution of the testing method.

[0062] During rotation of the first component, the torque response is measured and recorded at box 308. In some embodiments, rotation of the first component is speed- controlled. In some embodiments, rotation of the first component is torque-controlled. In some embodiments, the speed and / or torque of the rotation is programmed to replicate retraction timing of a mechanical time of a medication delivery device as described above. In some embodiments, a predetermined, desired retraction time of a medication delivery device may serve as a nominal control limit for the testing fixture and / or as upper or lower control limits for the testing fixture.

[0063] For example, in some embodiments, the testing fixture is set to a predetermined rotation time, with the torque response, or resistive torque, measured by theload cell and recorded. The torque response may vary according to the 3D transient behavior of the damping material as described above, and accounts for non-homogenous flow fields and non-uniform deformation rates which may be caused by variations in the gap of the second component, the fins of the first component and the fit between the fins and the collective inner surface of the gap walls of the second component, other internal part features of the gel containment assembly, the flex of the plastic parts of the gel containment assembly, manufacturing tolerance variations, and the surface finish or roughness of the first component and the second component contacting the damping material. Furthermore, damping material may be tested after exposure to different environmental conditions, e.g., temperature, time, shelf life, etc., to determine how each tested damping material may perform in real world scenarios.

[0064] In some embodiments, the testing fixture may be provided with a predetermined rotation angle and a predetermined rotation time, with the resistive torque measured and recorded for each testing instance. Different damping materials (e.g., damping materials having varying proportions of thixotropic additives resulting in different shear-rated dependent viscosities) may be tested, with results then compared. In some embodiments, the testing fixture may be provided with a predetermined rotation angle and a predetermined rotation time for the same or similar damping material at different measured amount levels (e.g., grams of damping material), with the resistive torque measured and recorded for each testing instance. The results for each measured amount level may compared. In any of the above embodiments, the provided testing method may be repeated with different predetermined times and / or rotations. For example, the predetermined rotation angle may be 10°, 20°, 30°, 40°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 100°, 150°, 200°, 250°, 300°, 360°, or any rotation angle therebetween. In many embodiments, the predetermined rotation angle may be 70 degrees. In some examples, the predetermined rotation time may be 0.5 s, 0.7 s, 0.85 s, 1 s, etc. The testing methods provided herein may be repeated at one or more variable predetermined rotation angles and / or one or more variable predetermined rotation times, with the resulting resistive torque measured and recorded. The relative rotational rates can also be varied, but can be in the range from 60 degrees / second to 120 degrees / second.

[0065] FIG. 15 illustrates an exemplary results curve for purposes of illustrating characterization of results obtained using the testing methods described above. Graph 400 illustrates a representative curve 402 which plots the measured resistive torque as described above as a function of the rotation angle during rotation of the first component. For example,as the first component rotates, the load cell is constantly measuring the resistive torque, providing representative curve 402. An initial slope, or first region 404, of representative curve 402 illustrates the elastic region or the stiffness of the tested damping gel. In other words, first region 404 is representative of the ability of the damping gel’s ability to return to its original form after being subjected to the force of rotation.

[0066] A yield point peak, or second region 406, of representative curve 402 illustrates the point of the maximum resistive torque of the tested damping gel, representative of the material yield stress of the tested damping gel. In other words, second region 406 is representative of the maximum responsive force the tested damping material can apply to the testing fixture. A decline slope, or third region 408, of representative curve 402 is representative of thixotropic shear-thinning of the testing damping gel, or the change in viscosity of the testing damping gel over time A plateau, or fourth region 410, of representative curve 402 is representative of a steady state of the tested damping gel. The area under the curve 412 is representative of the work required to complete the testing method, i.e., the product of the torque and rotation. The results and demonstration of these properties varies according to the testing damping gel. In other words, the actual curve obtained during the testing method may vary from representative curve 402, and may, in some instances, vary greatly from representative curve 402. As the spring is released, the spring first encounters resistance due to the yield stress of the damping gel. The next stage in the behavior of the damping gel is shear thinning wherein the resistance decreases. As described above, in FIG. 15, the first region 404 represents the stiffness, and the second region 406, collectively with first region 404, is the resistance. The third region 408 is the shear thinning (that is, declining resistance). The fourth region 410 is the constant resistance phase. All these regions can change depending on the viscosity (or non-Newtonian behavior), which the systems and methods described herein can capture. The systems and methods described herein can characterize the “resistive drag” offered by the device (that is, 3-way interaction between the first component (shown as a follower), damping gel, and the second component (shown as the damping collar) for this contribution to the delay time. The resistance drag can be a function of the viscosity, radius of the components, damping compound wetted surface area of the components, and the gap size in between the first and second components.Example

[0067] Graph 500 of FIG. 16 illustrates varying curves representative of materials having varying viscosities. Each of three damping materials were disposed in an amount of0.155 g within a gel containment assembly as described above, which was then coupled to a testing fixture similar to that described above. The testing fixture was preset at an 70° rotation angle, and the first component of the gel containment assembly was rotated relative to the second component of the gel containment assembly at a speed of 80 degrees / second, as discussed above. The resistive torque was measured by a load cell as described above, recorded, and plotted as a function of the rotation angle. The testing method was completed 10 times for each tested material, and the results for each material were averaged and plotted as shown in graph 500.

[0068] For example, curve 502 provides resistive torque by rotational angle results of a material having a viscosity of 664.5 Pa*s, including the representative regions as described above, and demonstrates an area under the curve of 637.2 Nmm*deg. Curve 504 provides resistive torque by rotation angle results of a material having a viscosity of 776.7 Pa*s, including the representative regions as described above, and demonstrates an area under the curve of 720.0 Nmm*deg. Curve 506 provides resistive torque by rotation angle results of a material having a viscosity of 854.5 Pa*s, including the representative regions as described above, and demonstrates an area under the curve of 739.7 Nmm*deg. The results, such as, for example, for a damping gel based on PDMS silicone oil with PTFE or Teflon as the thixotropic additive, demonstrate that resistive torque is a function of viscosity, i.e., the greater the viscosity of the tested material, the higher is the resistive torque.

[0069] While this invention has been described as having exemplary designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

[0070] Various aspects are described in this disclosure, which include, but are not limited to, the following aspects:

[0071] (1) A method for testing mechanical timing of a mechanical device, the method comprising: detecting a first position of a first component in nested arrangement with a second component, the first component communicatively coupled with a load cell, and including a substance positioned between the first component and the second component; triggering rotation of the first component relative to the second component; detecting angularposition movement of the first component during rotation; detecting resistive torque during position movement of the first component with the load cell; and comparing the detected resistive torque with the detected angular position movement.

[0072] (2) The method of aspect 1, wherein triggering rotation of the first component relative to the second component includes releasing a loaded torsional spring coupled to the first component.

[0073] (3) The method of any one of aspects 1 and 2, wherein triggering rotation of the first component relative to the second component includes operating an actuator configured to rotate the first component.

[0074] (4) The method of any one of aspects 1-3, wherein rotation of the first component relative to the second component is speed-controlled at a predetermined speed.

[0075] (5) The method of any one of aspects 1-4, wherein angular position movement of the first component includes a predetermined degree of angular movement.

[0076] (6) The method of any one of aspects 1-5, further comprising arranging the first component and the second component in a stacked arrangement on the load cell.

[0077] (7) The method of any one of aspects 1-6, wherein the first component and the second component are formed of plastic.

[0078] (8) The method of any one of aspects 1-7, wherein the substance is a damping material.

[0079] (9) The method of any one of aspects 1-8, further comprising removably fixing the second component in place to prevent rotation of the second component.

[0080] (10) A system for testing mechanical timing of a mechanical device, the system comprising: a first component and a second component rotatably arranged; a rotational member coupled to the first component; a load cell communicatively coupled to the first component; and a substance disposed between the first component and the second component.

[0081] (11) The system of aspect 10, wherein the first component and the second component are arranged in a stacked arrangement on the load cell.

[0082] (12) The system of any one of aspects 10-12, wherein the rotational member is an actuator arm configured to rotate the first component relative to the second component.

[0083] (13) The system of aspect 12, further comprising a third component coupled to the first component and configured to interface with the actuator arm to facilitate rotation of the first component.

[0084] (14) The system of aspect 13, wherein the third component is coupled to the first component with a tab-in-groove arrangement.

[0085] (15) The system of any one of aspects 13-14, wherein the third component is configured to receive at least a portion of the actuator arm.

[0086] (16) The system of any one of aspects 10-12, wherein the rotation member is a torsional spring coupled to the first component.

[0087] (17) The system of any one of aspects 10-16, wherein the first component and the second component are formed of plastic.

[0088] (18) The system of any one of aspects 10-17, wherein the first component and the second component are in a nested arrangement.

[0089] (19) The system of any one of aspects 10-18, further comprising a pin configured to be received by the second component to prevent rotation of the second component.

[0090] (20) The system of any one of aspects 10-19, wherein the substance is a damping material.

Claims

CLAIMS:

1. A method for testing mechanical timing of a mechanical device, the method comprising: detecting a first position of a first component in nested arrangement with a second component, the first component communicatively coupled with a load cell, and including a substance positioned between the first component and the second component; triggering rotation of the first component relative to the second component; detecting angular position movement of the first component during rotation; detecting resistive torque during position movement of the first component with the load cell; and comparing the detected resistive torque with the detected angular position movement.

2. The method of claim 1 , wherein triggering rotation of the first component relative to the second component includes releasing a loaded torsional spring coupled to the first component .

3. The method of any one claims 1-2, wherein triggering rotation of the first component relative to the second component includes operating an actuator configured to rotate the first component.

4. The method of any one of claims 1-3, wherein rotation of the first component relative to the second component is speed-controlled at a predetermined speed.

5. The method of any one of claims 1-4, wherein angular position movement of the first component includes a predetermined degree of angular movement.

6. The method of any one of claims 1-5, further comprising arranging the first component and the second component in a stacked arrangement on the load cell.

7. The method of any one of claims 1-6, wherein the first component and the second component are formed of plastic.

8. The method of any one claims 1-7, wherein the substance is a damping material.

9. The method of any one of claims 1-8, further comprising removably fixing the second component in place to prevent rotation of the second component.

10. A system for testing mechanical timing of a mechanical device, the system comprising: a first component and a second component rotatably arranged; a rotational member coupled to the first component; a load cell communicatively coupled to the first component; and a substance disposed between the first component and the second component.

11. The system of claim 10, wherein the first component and the second component are arranged in a stacked arrangement on the load cell.

12. The system of any one of claims 10-11, wherein the rotational member is an actuator arm configured to rotate the first component relative to the second component.

13. The system of claim 12, further comprising a third component coupled to the first component and configured to interface with the actuator arm to facilitate rotation of the first component.

14. The system of claim 13, wherein the third component is coupled to the first component with a tab-in-groove arrangement.

15. The system of claim 13, wherein the third component is configured to receive at least a portion of the actuator arm.

16. The system of any one of claims 10-15, wherein the rotation member is a torsional spring coupled to the first component.

17. The system of any one of claims 10-16, wherein the first component and the second component are formed of plastic.

18. The system of any one of claims 10-17, wherein the first component and the second component are in a nested arrangement.

19. The system of any one of claims 10-18, further comprising a pin configured to be received by the second component to prevent rotation of the second component.

20. The system of any one of claims 10-19, wherein the substance is a damping material.

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