Unequal stiffness spring device for CPR test equipment

Abstract

The utility model relates to the technical field of medical equipment, and discloses an unequal-rigidity spring device for CPR test equipment, which comprises two sections of linear compression springs with different rigidities, and the two sections of linear compression springs are mounted on the CPR test equipment. The linear compression springs are nested and connected into a whole; the rigidity of each section of linear compression spring is increased or decreased progressively; the coarse rigidity K'of each section of the linear compression spring is obtained according to the load F and the pressing depth X of each section of the spring; the accurate rigidity K of each section of the linear compression spring is obtained according to the effective coil number, the spring pitch diameter, the spring wire diameter and the spring coefficient of each section of the spring. The rigidity of the linear compression spring is designed, so that multiple sections of linear compression springs with different rigidities are connected into a whole, and the assembly space is reduced.

Description

Technical Field

[0001] This application relates to the field of medical instrument technology, and in particular to an unequal stiffness spring device for CPR testing equipment. Background Technology

[0002] The spring compression device used in CPR testing equipment requires a load of 471N when the spring is compressed by 40mm and 1108N when compressed by 60mm. Using the formula F=KX, the spring stiffness K value differs at these two positions. Existing technologies often design two springs in parallel, but this is cumbersome to install, requiring more installation space and a complex installation structure. Summary of the Invention

[0003] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0004] This utility model provides an unequal stiffness spring device for CPR testing equipment, which solves the problem that the existing unequal stiffness springs, which are designed with two springs connected in parallel, are relatively troublesome to install, require more installation space and have a complicated installation structure.

[0005] This utility model provides an unequal stiffness spring device for CPR testing equipment, comprising two linear compression springs with different stiffnesses, which are nested and connected as a whole and installed on the CPR testing equipment; the stiffness of each linear compression spring increases progressively; the coarse stiffness K' of each linear compression spring is obtained based on the load F and the compression depth X of each spring; the accurate stiffness K of each linear compression spring is obtained based on the effective number of coils, spring mean diameter, spring wire diameter, and spring constant of each spring.

[0006] The present invention, which adopts the above technical solution, designs the stiffness of the linear compression spring so that multiple linear compression springs with unequal stiffness are connected into one piece, thereby reducing the assembly space.

[0007] Preferably, the rough stiffness is K' = F / X.

[0008] Preferably, K1 = (G*d^4) / (8*n1*D^3), K2 = (G*d^4) / (8*n2*D^3); where K1 is the accurate spring stiffness of the first spring section, K2 is the accurate spring stiffness of the second spring section, n1 is the effective number of turns of the entire spring, n2 is the effective number of turns of the large pitch, D is the mean diameter of the spring, d is the spring wire diameter, and G is the spring constant.

[0009] Preferably, Z = (sd)*n; the second compression load = K1*Z + K2(XZ); where Z is the inflection point value, which is the inflection point position of the linear compression spring K1 to K2, s is the small pitch, which is the distance between each small spring of the first section, d is the spring wire diameter, and n is the total effective number of coils of the linear compression spring.

[0010] Preferably, the linear compression spring has a wire diameter of 6mm and a spring mean diameter of 41.8mm.

[0011] Preferably, the linear compression spring has one coil at each end and the ends are ground flat.

[0012] Preferably, the maximum pitch of each linear compression spring is equal.

[0013] Preferably, the free length of the small pitch = small pitch * effective number of small pitch coils + 1.5 times the spring wire diameter; the length of the large pitch = total free length - small pitch length - turning length = large pitch * effective number of large pitch coils + 1.5 times the spring wire diameter.

[0014] The beneficial effect of this utility model is that by designing the stiffness of the linear compression spring, multiple linear compression springs with unequal stiffness can be connected into one piece, thus reducing the assembly space.

[0015] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0017] Figure 1 This is a schematic diagram of the unequal stiffness spring device used in CPR testing equipment. Detailed Implementation

[0018] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments; however, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0019] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] The specific implementation method is described below with reference to the accompanying drawings.

[0021] For example, see Figure 1 As shown, the structure of an unequal stiffness spring device for CPR testing equipment includes two linear compression springs with different stiffnesses, which are nested and connected as a whole; the stiffness of each linear compression spring increases progressively; the coarse stiffness K' of each linear compression spring is obtained based on the load F and the pressing depth X of each spring; the accurate stiffness K of each linear compression spring is obtained based on the effective number of coils, spring mean diameter, spring wire diameter, and spring constant of each spring.

[0022] Preferably, the rough stiffness is K' = F / X.

[0023] In some embodiments, the assembly space for the spring is less than 48 mm in diameter and less than 250 mm in height. When compressed to a depth of 40 mm, the load is 471 N; when compressed to 60 mm, the load is 1108 N. According to F = KX, the rough stiffness K1' = 471 N / 40 mm = 17.8 N / mm when compressed to 40 mm, and the rough stiffness K2' = 1108 N / 60 mm = 18.47 N / mm when compressed to 60 mm. Therefore, the spring stiffness is increasing. Designing it as a combination of two springs with equal pitch greatly reduces the assembly space.

[0024] Preferably, K1 = (G*d^4) / (8*n1*D^3), K2 = (G*d^4) / (8*n2*D^3); where K1 is the accurate spring stiffness of the first spring section, K2 is the accurate spring stiffness of the second spring section, n1 is the effective number of turns of the entire spring, n2 is the effective number of turns of the large pitch, D is the mean diameter of the spring, d is the spring wire diameter, and G is the spring constant.

[0025] Preferably, Z = (sd)*n; the second compression load = K1*Z + K2(XZ); where Z is the inflection point value, which is the inflection point position of the linear compression spring K1 to K2, s is the small pitch, which is the distance between each small spring of the first section, d is the spring wire diameter, and n is the total effective number of coils of the linear compression spring.

[0026] Preferably, the linear compression spring has a wire diameter of 6mm and a spring mean diameter of 41.8mm.

[0027] In some embodiments, based on the assembly space, the spring wire diameter is 6mm and the mean diameter is 41.8mm. Substituting into the formula: K1=(G*d^4) / (8*n1*D^3), we calculate n1=15. K2 is determined by the number of small pitch coils, but the number of small pitch coils affects the turning point position of the spring from K1 to K2. Therefore, determining the number of small pitch coils requires considering the turning point position of the spring. If the first compression of the spring is 40mm, then the stiffness will definitely start to change after 40mm. If the spring stiffness starts to change at a compression of 45mm, based on the value of the turning point, using the formula: Turning point value=(small pitch - wire diameter)*total effective coils=45mm, substituting the total effective coils as 15 and the wire diameter as 6mm, we obtain a small pitch of 9mm. Therefore, the second compression load=K1*45mm+k2*(60mm-45mm)=1108N, and we calculate K2=38.58. From the formula: K2=(G*d^4) / (8*n2*D^3). n2 is the effective number of revolutions for the large pitch, calculated to be n2=4.6, then the effective number of revolutions for the small pitch is n3=15-4.6=10.4.

[0028] Preferably, the linear compression spring has one turn at each end, and the ends are ground flat. This ensures that the spring is installed smoothly and reliably.

[0029] Preferably, the maximum pitch of each linear compression spring is equal.

[0030] Preferably, the free length of the smaller pitch = smaller pitch * effective number of coils in the smaller pitch + 1.5 times the spring wire diameter; the length of the larger pitch = total free length - smaller pitch length - bend length = larger pitch * effective number of coils in the larger pitch + 1.5 times the spring wire diameter. Further, substituting the number of coils in the larger pitch as 4.6, the calculated larger pitch = 27.9 mm. The smaller pitch is 9 mm with an effective number of coils of 10.4, and the larger pitch is 27.9 mm with an effective number of coils of 4.6.

[0031] The beneficial effect of this utility model is that by designing the stiffness of the linear compression spring, multiple linear compression springs with unequal stiffness can be connected into one piece, thus reducing the assembly space.

[0032] This utility model is not limited to the specific embodiments described above. The basic principles, main features, and advantages of this application have been shown and described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

[0033] The embodiments disclosed herein are merely illustrative. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of the embodiments disclosed herein.

Claims

1. An unequal stiffness spring arrangement for a CPR testing apparatus, characterised in that, The linear compression spring comprises two sections with different stiffness, which are connected as a whole and installed on a CPR testing device; the stiffness of each section of the linear compression spring increases; the rough stiffness K' of each section of the linear compression spring is obtained according to the load F and the pressing depth X of each section of the spring; and the accurate stiffness K of each section of the linear compression spring is obtained according to the effective number of turns, the spring diameter, the spring wire diameter and the spring coefficient of each section of the spring.

2. The unequal stiffness spring arrangement for a CPR testing device of claim 1, wherein, Rough stiffness K' = F / X.

3. The unequal stiffness spring apparatus for a CPR testing device of claim 1, wherein, K1=(G*d^4) / (8*n1*D^3), K2=(G*d^4) / (8*n2*D^3); wherein K1 is the accurate spring stiffness of the first section of spring, K2 is the accurate spring stiffness of the second section of spring, n1 is the effective number of turns of the whole spring, n2 is the effective number of turns of the large pitch, D is the spring diameter, d is the spring wire diameter, and G is the spring coefficient.

4. The unequal stiffness spring arrangement for a CPR testing device of claim 3, wherein, Z=(s-d)*n; second compression load = K1*Z + K2(X-Z); wherein Z is the turning point value, which is the turning point position of the linear compression spring K1 to K2, s is the small pitch, which is the interval between each small section of spring of the first section of spring, d is the spring wire diameter, and n is the total effective number of turns of the linear compression spring.

5. The unequal stiffness spring arrangement for a CPR testing device of claim 4, wherein, The linear compression spring has a wire diameter of 6 mm and a spring diameter of 41.8 mm.

6. The unequal stiffness spring apparatus for a CPR testing device of claim 1, wherein, Each end of the linear compression spring is wound with one turn, and the end is ground flat.

7. The unequal stiffness spring apparatus for a CPR testing device of claim 1, wherein, The large pitches of each linear compression spring are equal.

8. The unequal stiffness spring apparatus for a CPR testing device of claim 1, wherein, Small pitch free length = small pitch * small pitch effective number of turns + 1.5 times spring wire diameter; large pitch length = total free length - small pitch length - turning length = large pitch * large pitch effective number of turns + 1.5 times spring wire diameter.

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